MCL/sf/os/fshell: comparison libraries/spcre/libpcre/pcre/ChangeLog

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--1:000000000000
+:7f656887cf89
+ChangeLog for PCRE
+------------------
+Version 7.8 05-Sep-08
+---------------------
+1.  Replaced UCP searching code with optimized version as implemented for Ad
+Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
+stage table and inline lookup instead of a function, giving speed ups of 2
+to 5 times on some simple patterns that I tested. Permission was given to
+distribute the MultiStage2.py script that generates the tables (it's not in
+the tarball, but is in the Subversion repository).
+2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
+scripts.
+3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
+a group with a zero qualifier. The result of the study could be incorrect,
+or the function might crash, depending on the pattern.
+4.  Caseless matching was not working for non-ASCII characters in back
+references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
+It now works when Unicode Property Support is available.
+5.  In pcretest, an escape such as \x{de} in the data was always generating
+a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
+non-UTF-8 mode. If the value is greater than 255, it gives a warning about
+truncation.
+6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
+7.  Added two (int) casts to pcregrep when printing the difference of two
+pointers, in case they are 64-bit values.
+8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
+test 2 if it fails.
+9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
+and a #define of that name to empty if it is not externally set. This is to
+allow users of MSVC to set it if necessary.
+10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
+the convenience functions in the pcre_get.c source file.
+11. An option change at the start of a pattern that had top-level alternatives
+could cause overwriting and/or a crash. This command provoked a crash in
+some environments:
+printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
+This potential security problem was recorded as CVE-2008-2371.
+12. For a pattern where the match had to start at the beginning or immediately
+after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
+pcre_dfa_exec() could read past the end of the passed subject if there was
+no match. To help with detecting such bugs (e.g. with valgrind), I modified
+pcretest so that it places the subject at the end of its malloc-ed buffer.
+13. The change to pcretest in 12 above threw up a couple more cases when pcre_
+exec() might read past the end of the data buffer in UTF-8 mode.
+14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
+the data contained the byte 0x85 as part of a UTF-8 character within its
+first line. This applied both to normal and DFA matching.
+15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
+/^[^d]*?$/8 failed to match "abc".
+16. Added a missing copyright notice to pcrecpp_internal.h.
+17. Make it more clear in the documentation that values returned from
+pcre_exec() in ovector are byte offsets, not character counts.
+18. Tidied a few places to stop certain compilers from issuing warnings.
+19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
+supplied by Stefan Weber. I made a further small update for 7.8 because
+there is a change of source arrangements: the pcre_searchfuncs.c module is
+replaced by pcre_ucd.c.
+Version 7.7 07-May-08
+---------------------
+1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
+a string to a long long, pretend we don't even have a long long." This is
+done by checking for the strtoq, strtoll, and _strtoi64 functions.
+2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
+pre-7.6 versions, which defined a global no_arg variable instead of putting
+it in the RE class. (See also #8 below.)
+3.  Remove a line of dead code, identified by coverity and reported by Nuno
+Lopes.
+4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
+(1) The include/exclude patterns were being applied to the whole pathnames
+of files, instead of just to the final components.
+(2) If there was more than one level of directory, the subdirectories were
+skipped unless they satisfied the include/exclude conditions. This is
+inconsistent with GNU grep (and could even be seen as contrary to the
+pcregrep specification - which I improved to make it absolutely clear).
+The action now is always to scan all levels of directory, and just
+apply the include/exclude patterns to regular files.
+5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
+--exclude_dir in the tests to avoid scanning .svn directories.
+6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
+NUL character as backslash + 0 rather than backslash + NUL, because PCRE
+doesn't support NULs in patterns.
+7.  Added some missing "const"s to declarations of static tables in
+pcre_compile.c and pcre_dfa_exec.c.
+8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
+caused by fix #2  above. (Subsequently also a second patch to fix the
+first patch. And a third patch - this was a messy problem.)
+9.  Applied Craig's patch to remove the use of push_back().
+10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
+matching function regexec().
+11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
+which, however, unlike Perl's \g{...}, are subroutine calls, not back
+references. PCRE supports relative numbers with this syntax (I don't think
+Oniguruma does).
+12. Previously, a group with a zero repeat such as (...){0} was completely
+omitted from the compiled regex. However, this means that if the group
+was called as a subroutine from elsewhere in the pattern, things went wrong
+(an internal error was given). Such groups are now left in the compiled
+pattern, with a new opcode that causes them to be skipped at execution
+time.
+13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
+to the way PCRE behaves:
+(a) A lone ] character is dis-allowed (Perl treats it as data).
+(b) A back reference to an unmatched subpattern matches an empty string
+(Perl fails the current match path).
+(c) A data ] in a character class must be notated as \] because if the
+first data character in a class is ], it defines an empty class. (In
+Perl it is not possible to have an empty class.) The empty class []
+never matches; it forces failure and is equivalent to (*FAIL) or (?!).
+The negative empty class [^] matches any one character, independently
+of the DOTALL setting.
+14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
+non-existent subpattern following a character class starting with ']' and
+containing () gave an internal compiling error instead of "reference to
+non-existent subpattern". Fortunately, when the pattern did exist, the
+compiled code was correct. (When scanning forwards to check for the
+existencd of the subpattern, it was treating the data ']' as terminating
+the class, so got the count wrong. When actually compiling, the reference
+was subsequently set up correctly.)
+15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
+it was being rejected as not supported by pcre_dfa_exec(), even though
+other assertions are supported. I have made pcre_dfa_exec() support
+(*FAIL).
+16. The implementation of 13c above involved the invention of a new opcode,
+OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
+cannot be changed at match time, I realized I could make a small
+improvement to matching performance by compiling OP_ALLANY instead of
+OP_ANY for "." when DOTALL was set, and then removing the runtime tests
+on the OP_ANY path.
+17. Compiling pcretest on Windows with readline support failed without the
+following two fixes: (1) Make the unistd.h include conditional on
+HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
+18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
+ncurses library to be included for pcretest when ReadLine support is
+requested, but also to allow for it to be overridden. This patch came from
+Daniel Bergström.
+19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
+as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
+any errors with the current Unicode tables. Thanks to Peter Kankowski for
+spotting this.
+Version 7.6 28-Jan-08
+---------------------
+1.  A character class containing a very large number of characters with
+codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
+overflow.
+2.  Patch to cut out the "long long" test in pcrecpp_unittest when
+HAVE_LONG_LONG is not defined.
+3.  Applied Christian Ehrlicher's patch to update the CMake build files to
+bring them up to date and include new features. This patch includes:
+- Fixed PH's badly added libz and libbz2 support.
+- Fixed a problem with static linking.
+- Added pcredemo. [But later removed - see 7 below.]
+- Fixed dftables problem and added an option.
+- Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
+HAVE_LONG_LONG.
+- Added readline support for pcretest.
+- Added an listing of the option settings after cmake has run.
+4.  A user submitted a patch to Makefile that makes it easy to create
+"pcre.dll" under mingw when using Configure/Make. I added stuff to
+Makefile.am that cause it to include this special target, without
+affecting anything else. Note that the same mingw target plus all
+the other distribution libraries and programs are now supported
+when configuring with CMake (see 6 below) instead of with
+Configure/Make.
+5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
+This is an attempt to solve the reported problem "pcrecpp::no_arg is not
+exported in the Windows port". It has not yet been confirmed that the patch
+solves the problem, but it does no harm.
+6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
+NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
+with CMake, and also correct the comment about stack recursion.
+7.  Remove the automatic building of pcredemo from the ./configure system and
+from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
+of a program that users should build themselves after PCRE is installed, so
+building it automatically is not really right. What is more, it gave
+trouble in some build environments.
+8.  Further tidies to CMakeLists.txt from Sheri and Christian.
+Version 7.5 10-Jan-08
+---------------------
+1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
+values in parens when parsing an RE using the C++ wrapper."
+2.  Negative specials like \S did not work in character classes in UTF-8 mode.
+Characters greater than 255 were excluded from the class instead of being
+included.
+3.  The same bug as (2) above applied to negated POSIX classes such as
+[:^space:].
+4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
+defined or documented. It seems to have been a typo for PCRE_STATIC, so
+I have changed it.
+5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
+first named subpattern) and a construct such as (?&a) would reference the
+first named subpattern whose name started with "a" (in other words, the
+length check was missing). Both these problems are fixed. "Subpattern name
+expected" is now given for (?&) (a zero-length name), and this patch also
+makes it give the same error for \k'' (previously it complained that that
+was a reference to a non-existent subpattern).
+6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
+this is right because (?- can be followed by option settings as well as by
+digits. I have, however, made the messages clearer.
+7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
+than the number used in the conditional) now cause a compile-time error.
+This is actually not compatible with Perl, which accepts such patterns, but
+treats the conditional as always being FALSE (as PCRE used to), but it
+seems to me that giving a diagnostic is better.
+8.  Change "alphameric" to the more common word "alphanumeric" in comments
+and messages.
+9.  Fix two occurrences of "backslash" in comments that should have been
+"backspace".
+10. Remove two redundant lines of code that can never be obeyed (their function
+was moved elsewhere).
+11. The program that makes PCRE's Unicode character property table had a bug
+which caused it to generate incorrect table entries for sequences of
+characters that have the same character type, but are in different scripts.
+It amalgamated them into a single range, with the script of the first of
+them. In other words, some characters were in the wrong script. There were
+thirteen such cases, affecting characters in the following ranges:
+U+002b0 - U+002c1
+U+0060c - U+0060d
+U+0061e - U+00612
+U+0064b - U+0065e
+U+0074d - U+0076d
+U+01800 - U+01805
+U+01d00 - U+01d77
+U+01d9b - U+01dbf
+U+0200b - U+0200f
+U+030fc - U+030fe
+U+03260 - U+0327f
+U+0fb46 - U+0fbb1
+U+10450 - U+1049d
+12. The -o option (show only the matching part of a line) for pcregrep was not
+compatible with GNU grep in that, if there was more than one match in a
+line, it showed only the first of them. It now behaves in the same way as
+GNU grep.
+13. If the -o and -v options were combined for pcregrep, it printed a blank
+line for every non-matching line. GNU grep prints nothing, and pcregrep now
+does the same. The return code can be used to tell if there were any
+non-matching lines.
+14. Added --file-offsets and --line-offsets to pcregrep.
+15. The pattern (?=something)(?R) was not being diagnosed as a potentially
+infinitely looping recursion. The bug was that positive lookaheads were not
+being skipped when checking for a possible empty match (negative lookaheads
+and both kinds of lookbehind were skipped).
+16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
+inclusion of <windows.h> to before rather than after the definition of
+INVALID_FILE_ATTRIBUTES (patch from David Byron).
+17. Specifying a possessive quantifier with a specific limit for a Unicode
+character property caused pcre_compile() to compile bad code, which led at
+runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
+are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
+caused the error; without that there was no problem.
+18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
+19. Added --enable-pcretest-libreadline.
+20. In pcrecpp.cc, the variable 'count' was incremented twice in
+RE::GlobalReplace(). As a result, the number of replacements returned was
+double what it should be. I removed one of the increments, but Craig sent a
+later patch that removed the other one (the right fix) and added unit tests
+that check the return values (which was not done before).
+21. Several CMake things:
+(1) Arranged that, when cmake is used on Unix, the libraries end up with
+the names libpcre and libpcreposix, not just pcre and pcreposix.
+(2) The above change means that pcretest and pcregrep are now correctly
+linked with the newly-built libraries, not previously installed ones.
+(3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
+22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
+crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
+UTF-8 newline character). The key issue is that the pattern starts .*;
+this means that the match must be either at the beginning, or after a
+newline. The bug was in the code for advancing after a failed match and
+checking that the new position followed a newline. It was not taking
+account of UTF-8 characters correctly.
+23. PCRE was behaving differently from Perl in the way it recognized POSIX
+character classes. PCRE was not treating the sequence [:...:] as a
+character class unless the ... were all letters. Perl, however, seems to
+allow any characters between [: and :], though of course it rejects as
+unknown any "names" that contain non-letters, because all the known class
+names consist only of letters. Thus, Perl gives an error for [[:1234:]],
+for example, whereas PCRE did not - it did not recognize a POSIX character
+class. This seemed a bit dangerous, so the code has been changed to be
+closer to Perl. The behaviour is not identical to Perl, because PCRE will
+diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
+treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
+Perl does, and where it didn't before.
+24. Rewrite so as to remove the single use of %n from pcregrep because in some
+Windows environments %n is disabled by default.
+Version 7.4 21-Sep-07
+---------------------
+1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
+means that a class such as [\s] counted as "explicit reference to CR or
+LF". That isn't really right - the whole point of the change was to try to
+help when there was an actual mention of one of the two characters. So now
+the change happens only if \r or \n (or a literal CR or LF) character is
+encountered.
+2.  The 32-bit options word was also used for 6 internal flags, but the numbers
+of both had grown to the point where there were only 3 bits left.
+Fortunately, there was spare space in the data structure, and so I have
+moved the internal flags into a new 16-bit field to free up more option
+bits.
+3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
+but did not set the internal JCHANGED flag - either of these is enough to
+control the way the "get" function works - but the PCRE_INFO_JCHANGED
+facility is supposed to tell if (?J) was ever used, so now (?J) at the
+start sets both bits.
+4.  Added options (at build time, compile time, exec time) to change \R from
+matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
+5.  doc/pcresyntax.html was missing from the distribution.
+6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
+compatibility, even though it is no longer used.
+7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
+strtoull to pcrecpp.cc to select the available functions in WIN32 when the
+windows.h file is present (where different names are used). [This was
+reversed later after testing - see 16 below.]
+8.  Changed all #include <config.h> to #include "config.h". There were also
+some further <pcre.h> cases that I changed to "pcre.h".
+9.  When pcregrep was used with the --colour option, it missed the line ending
+sequence off the lines that it output.
+10. It was pointed out to me that arrays of string pointers cause lots of
+relocations when a shared library is dynamically loaded. A technique of
+using a single long string with a table of offsets can drastically reduce
+these. I have refactored PCRE in four places to do this. The result is
+dramatic:
+Originally:                          290
+After changing UCP table:            187
+After changing error message table:   43
+After changing table of "verbs"       36
+After changing table of Posix names   22
+Thanks to the folks working on Gregex for glib for this insight.
+11. --disable-stack-for-recursion caused compiling to fail unless -enable-
+unicode-properties was also set.
+12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
+13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
+checked only for CRLF.
+14. Added casts to pcretest.c to avoid compiler warnings.
+15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
+16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
+and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
+entirely. This removes changes made in 7 above.
+17. The CMake files have been updated, and there is now more information about
+building with CMake in the NON-UNIX-USE document.
+Version 7.3 28-Aug-07
+---------------------
+1. In the rejigging of the build system that eventually resulted in 7.1, the
+line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
+brackets there is not right, since it causes compilers to look for an
+installed pcre.h, not the version that is in the source that is being
+compiled (which of course may be different). I have changed it back to:
+#include "pcre.h"
+I have a vague recollection that the change was concerned with compiling in
+different directories, but in the new build system, that is taken care of
+by the VPATH setting the Makefile.
+2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
+when the subject happened to end in the byte 0x85 (e.g. if the last
+character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
+characters but of course it shouldn't be taken as a newline when it is part
+of another character. The bug was that, for an unlimited repeat of . in
+not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
+characters when looking for a newline.
+3. A small performance improvement in the DOTALL UTF-8 mode .* case.
+4. Debugging: adjusted the names of opcodes for different kinds of parentheses
+in debug output.
+5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
+long printing in the pcrecpp unittest when running under MinGW.
+6. ESC_K was left out of the EBCDIC table.
+7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
+parentheses; I made it 1000, which seemed large enough. Unfortunately, the
+limit also applies to "virtual nesting" when a pattern is recursive, and in
+this case 1000 isn't so big. I have been able to remove this limit at the
+expense of backing off one optimization in certain circumstances. Normally,
+when pcre_exec() would call its internal match() function recursively and
+immediately return the result unconditionally, it uses a "tail recursion"
+feature to save stack. However, when a subpattern that can match an empty
+string has an unlimited repetition quantifier, it no longer makes this
+optimization. That gives it a stack frame in which to save the data for
+checking that an empty string has been matched. Previously this was taken
+from the 1000-entry workspace that had been reserved. So now there is no
+explicit limit, but more stack is used.
+8. Applied Daniel's patches to solve problems with the import/export magic
+syntax that is required for Windows, and which was going wrong for the
+pcreposix and pcrecpp parts of the library. These were overlooked when this
+problem was solved for the main library.
+9. There were some crude static tests to avoid integer overflow when computing
+the size of patterns that contain repeated groups with explicit upper
+limits. As the maximum quantifier is 65535, the maximum group length was
+set at 30,000 so that the product of these two numbers did not overflow a
+32-bit integer. However, it turns out that people want to use groups that
+are longer than 30,000 bytes (though not repeat them that many times).
+Change 7.0/17 (the refactoring of the way the pattern size is computed) has
+made it possible to implement the integer overflow checks in a much more
+dynamic way, which I have now done. The artificial limitation on group
+length has been removed - we now have only the limit on the total length of
+the compiled pattern, which depends on the LINK_SIZE setting.
+10. Fixed a bug in the documentation for get/copy named substring when
+duplicate names are permitted. If none of the named substrings are set, the
+functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
+empty string.
+11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
+instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
+because the ] is interpreted as the first data character and the
+terminating ] is not found. PCRE has been made compatible with Perl in this
+regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
+cause memory overwriting.
+10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
+string has been matched (to stop an infinite loop). It was not recognizing
+a conditional subpattern that could match an empty string if that
+subpattern was within another subpattern. For example, it looped when
+trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
+condition was not nested. This bug has been fixed.
+12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
+past the start of the subject in the presence of bytes with the top bit
+set, for example "\x8aBCD".
+13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
+(*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
+14. Optimized (?!) to (*FAIL).
+15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
+This restricts code points to be within the range 0 to 0x10FFFF, excluding
+the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
+full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
+does: it's just the validity check that is more restrictive.
+16. Inserted checks for integer overflows during escape sequence (backslash)
+processing, and also fixed erroneous offset values for syntax errors during
+backslash processing.
+17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
+for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
+18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
+caused an overrun.
+19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
+something other than just ASCII characters) inside a group that had an
+unlimited repeat caused a loop at compile time (while checking to see
+whether the group could match an empty string).
+20. Debugging a pattern containing \p or \P could cause a crash. For example,
+[\P{Any}] did so. (Error in the code for printing property names.)
+21. An orphan \E inside a character class could cause a crash.
+22. A repeated capturing bracket such as (A)? could cause a wild memory
+reference during compilation.
+23. There are several functions in pcre_compile() that scan along a compiled
+expression for various reasons (e.g. to see if it's fixed length for look
+behind). There were bugs in these functions when a repeated \p or \P was
+present in the pattern. These operators have additional parameters compared
+with \d, etc, and these were not being taken into account when moving along
+the compiled data. Specifically:
+(a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
+length.
+(b) An item such as \pL+ within a repeated group could cause crashes or
+loops.
+(c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
+"reference to non-existent subpattern" error.
+(d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
+24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
+characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
+25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
+26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
+character were causing crashes (broken optimization).
+27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
+\p or \P) caused a compile-time loop.
+28. More problems have arisen in unanchored patterns when CRLF is a valid line
+break. For example, the unstudied pattern [\r\n]A does not match the string
+"\r\nA" because change 7.0/46 below moves the current point on by two
+characters after failing to match at the start. However, the pattern \nA
+*does* match, because it doesn't start till \n, and if [\r\n]A is studied,
+the same is true. There doesn't seem any very clean way out of this, but
+what I have chosen to do makes the common cases work: PCRE now takes note
+of whether there can be an explicit match for \r or \n anywhere in the
+pattern, and if so, 7.0/46 no longer applies. As part of this change,
+there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
+pattern has explicit CR or LF references.
+29. Added (*CR) etc for changing newline setting at start of pattern.
+Version 7.2 19-Jun-07
+---------------------
+1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
+which is apparently normally available under Windows.
+2. Re-jig the pcregrep tests with different newline settings in an attempt
+to make them independent of the local environment's newline setting.
+3. Add code to configure.ac to remove -g from the CFLAGS default settings.
+4. Some of the "internals" tests were previously cut out when the link size
+was not 2, because the output contained actual offsets. The recent new
+"Z" feature of pcretest means that these can be cut out, making the tests
+usable with all link sizes.
+5. Implemented Stan Switzer's goto replacement for longjmp() when not using
+stack recursion. This gives a massive performance boost under BSD, but just
+a small improvement under Linux. However, it saves one field in the frame
+in all cases.
+6. Added more features from the forthcoming Perl 5.10:
+(a) (?-n) (where n is a string of digits) is a relative subroutine or
+recursion call. It refers to the nth most recently opened parentheses.
+(b) (?+n) is also a relative subroutine call; it refers to the nth next
+to be opened parentheses.
+(c) Conditions that refer to capturing parentheses can be specified
+relatively, for example, (?(-2)... or (?(+3)...
+(d) \K resets the start of the current match so that everything before
+is not part of it.
+(e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
+(f) \g{name} is another synonym - part of Perl 5.10's unification of
+reference syntax.
+(g) (?| introduces a group in which the numbering of parentheses in each
+alternative starts with the same number.
+(h) \h, \H, \v, and \V match horizontal and vertical whitespace.
+7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
+PCRE_INFO_JCHANGED.
+8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
+terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
+for detecting groups that can match an empty string.
+9. A pattern with a very large number of alternatives (more than several
+hundred) was running out of internal workspace during the pre-compile
+phase, where pcre_compile() figures out how much memory will be needed. A
+bit of new cunning has reduced the workspace needed for groups with
+alternatives. The 1000-alternative test pattern now uses 12 bytes of
+workspace instead of running out of the 4096 that are available.
+10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
+11. Applied patch from Google to remove an optimization that didn't quite work.
+The report of the bug said:
+pcrecpp::RE("a*").FullMatch("aaa") matches, while
+pcrecpp::RE("a*?").FullMatch("aaa") does not, and
+pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
+12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
+it matched the wrong number of bytes.
+Version 7.1 24-Apr-07
+---------------------
+1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
+that is more "standard", making use of automake and other Autotools. There
+is some re-arrangement of the files and adjustment of comments consequent
+on this.
+2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
+for recursive directory scanning broke on some systems because the files
+are not scanned in any specific order and on different systems the order
+was different. A call to "sort" has been inserted into RunGrepTest for the
+approprate test as a short-term fix. In the longer term there may be an
+alternative.
+3. I had an email from Eric Raymond about problems translating some of PCRE's
+man pages to HTML (despite the fact that I distribute HTML pages, some
+people do their own conversions for various reasons). The problems
+concerned the use of low-level troff macros .br and .in. I have therefore
+removed all such uses from the man pages (some were redundant, some could
+be replaced by .nf/.fi pairs). The 132html script that I use to generate
+HTML has been updated to handle .nf/.fi and to complain if it encounters
+.br or .in.
+4. Updated comments in configure.ac that get placed in config.h.in and also
+arranged for config.h to be included in the distribution, with the name
+config.h.generic, for the benefit of those who have to compile without
+Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
+5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
+Weber: (1) pcre_internal.h was missing some function renames; (2) updated
+makevp.bat for the current PCRE, using the additional files
+makevp_c.txt, makevp_l.txt, and pcregexp.pas.
+6. A Windows user reported a minor discrepancy with test 2, which turned out
+to be caused by a trailing space on an input line that had got lost in his
+copy. The trailing space was an accident, so I've just removed it.
+7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
+that is needed.
+8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
+as "const" (a) because they are and (b) because it helps the PHP
+maintainers who have recently made a script to detect big data structures
+in the php code that should be moved to the .rodata section. I remembered
+to update Builducptable as well, so it won't revert if ucptable.h is ever
+re-created.
+9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
+pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
+order to be able to cut out the UTF-8 tables in the latter when UTF-8
+support is not required. This saves 1.5-2K of code, which is important in
+some applications.
+Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
+so as not to refer to the tables, even though these functions will never be
+called when UTF-8 support is disabled. Otherwise there are problems with a
+shared library.
+10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
+(a) It was defining its arguments as char * instead of void *.
+(b) It was assuming that all moves were upwards in memory; this was true
+a long time ago when I wrote it, but is no longer the case.
+The emulated memove() is provided for those environments that have neither
+memmove() nor bcopy(). I didn't think anyone used it these days, but that
+is clearly not the case, as these two bugs were recently reported.
+11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
+and Detrail to create the HTML documentation, the .txt form of the man
+pages, and it removes trailing spaces from listed files. It also creates
+pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
+case, it wraps all the #defines with #ifndefs. This script should be run
+before "make dist".
+12. Fixed two fairly obscure bugs concerned with quantified caseless matching
+with Unicode property support.
+(a) For a maximizing quantifier, if the two different cases of the
+character were of different lengths in their UTF-8 codings (there are
+some cases like this - I found 11), and the matching function had to
+back up over a mixture of the two cases, it incorrectly assumed they
+were both the same length.
+(b) When PCRE was configured to use the heap rather than the stack for
+recursion during matching, it was not correctly preserving the data for
+the other case of a UTF-8 character when checking ahead for a match
+while processing a minimizing repeat. If the check also involved
+matching a wide character, but failed, corruption could cause an
+erroneous result when trying to check for a repeat of the original
+character.
+13. Some tidying changes to the testing mechanism:
+(a) The RunTest script now detects the internal link size and whether there
+is UTF-8 and UCP support by running ./pcretest -C instead of relying on
+values substituted by "configure". (The RunGrepTest script already did
+this for UTF-8.) The configure.ac script no longer substitutes the
+relevant variables.
+(b) The debugging options /B and /D in pcretest show the compiled bytecode
+with length and offset values. This means that the output is different
+for different internal link sizes. Test 2 is skipped for link sizes
+other than 2 because of this, bypassing the problem. Unfortunately,
+there was also a test in test 3 (the locale tests) that used /B and
+failed for link sizes other than 2. Rather than cut the whole test out,
+I have added a new /Z option to pcretest that replaces the length and
+offset values with spaces. This is now used to make test 3 independent
+of link size. (Test 2 will be tidied up later.)
+14. If erroroffset was passed as NULL to pcre_compile, it provoked a
+segmentation fault instead of returning the appropriate error message.
+15. In multiline mode when the newline sequence was set to "any", the pattern
+^$ would give a match between the \r and \n of a subject such as "A\r\nB".
+This doesn't seem right; it now treats the CRLF combination as the line
+ending, and so does not match in that case. It's only a pattern such as ^$
+that would hit this one: something like ^ABC$ would have failed after \r
+and then tried again after \r\n.
+16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
+in an attempt to make files that differ only in their line terminators
+compare equal. This works on Linux.
+17. Under certain error circumstances pcregrep might try to free random memory
+as it exited. This is now fixed, thanks to valgrind.
+19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
+"abc\r\n\r\n", it found an unwanted second match after the second \r. This
+was because its rules for how to advance for /g after matching an empty
+string at the end of a line did not allow for this case. They now check for
+it specially.
+20. pcretest is supposed to handle patterns and data of any length, by
+extending its buffers when necessary. It was getting this wrong when the
+buffer for a data line had to be extended.
+21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
+CRLF as a newline sequence.
+22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
+out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
+I have nevertheless tidied it up.
+23. Added some casts to kill warnings from HP-UX ia64 compiler.
+24. Added a man page for pcre-config.
+Version 7.0 19-Dec-06
+---------------------
+1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
+moving to gcc 4.1.1.
+2. The -S option for pcretest uses setrlimit(); I had omitted to #include
+sys/time.h, which is documented as needed for this function. It doesn't
+seem to matter on Linux, but it showed up on some releases of OS X.
+3. It seems that there are systems where bytes whose values are greater than
+127 match isprint() in the "C" locale. The "C" locale should be the
+default when a C program starts up. In most systems, only ASCII printing
+characters match isprint(). This difference caused the output from pcretest
+to vary, making some of the tests fail. I have changed pcretest so that:
+(a) When it is outputting text in the compiled version of a pattern, bytes
+other than 32-126 are always shown as hex escapes.
+(b) When it is outputting text that is a matched part of a subject string,
+it does the same, unless a different locale has been set for the match
+(using the /L modifier). In this case, it uses isprint() to decide.
+4. Fixed a major bug that caused incorrect computation of the amount of memory
+required for a compiled pattern when options that changed within the
+pattern affected the logic of the preliminary scan that determines the
+length. The relevant options are -x, and -i in UTF-8 mode. The result was
+that the computed length was too small. The symptoms of this bug were
+either the PCRE error "internal error: code overflow" from pcre_compile(),
+or a glibc crash with a message such as "pcretest: free(): invalid next
+size (fast)". Examples of patterns that provoked this bug (shown in
+pcretest format) are:
+/(?-x: )/x
+/(?x)(?-x: \s*#\s*)/
+/((?i)[\x{c0}])/8
+/(?i:[\x{c0}])/8
+HOWEVER: Change 17 below makes this fix obsolete as the memory computation
+is now done differently.
+5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
+wrapper classes; (b) implement a new function in the C++ scanner that is
+more efficient than the old way of doing things because it avoids levels of
+recursion in the regex matching; (c) add a paragraph to the documentation
+for the FullMatch() function.
+6. The escape sequence \n was being treated as whatever was defined as
+"newline". Not only was this contrary to the documentation, which states
+that \n is character 10 (hex 0A), but it also went horribly wrong when
+"newline" was defined as CRLF. This has been fixed.
+7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
+was being set to -1 for the "end of line" case (supposedly a value that no
+character can have). Though this value is never used (the check for end of
+line is "zero bytes in current character"), it caused compiler complaints.
+I've changed it to 0xffffffff.
+8. In pcre_version.c, the version string was being built by a sequence of
+C macros that, in the event of PCRE_PRERELEASE being defined as an empty
+string (as it is for production releases) called a macro with an empty
+argument. The C standard says the result of this is undefined. The gcc
+compiler treats it as an empty string (which was what was wanted) but it is
+reported that Visual C gives an error. The source has been hacked around to
+avoid this problem.
+9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
+builds of pcretest, and changed the call to _setmode() to use _O_BINARY
+instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
+of them did).
+10. Originally, pcretest opened its input and output without "b"; then I was
+told that "b" was needed in some environments, so it was added for release
+5.0 to both the input and output. (It makes no difference on Unix-like
+systems.) Later I was told that it is wrong for the input on Windows. I've
+now abstracted the modes into two macros, to make it easier to fiddle with
+them, and removed "b" from the input mode under Windows.
+11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
+12. Added -help and --help to pcretest as an official way of being reminded
+of the options.
+13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
+and pcrecpp.cc because they annoy compilers at high warning levels.
+14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
+15. Fixed an occurrence of == in configure.ac that should have been = (shell
+scripts are not C programs :-) and which was not noticed because it works
+on Linux.
+16. pcretest is supposed to handle any length of pattern and data line (as one
+line or as a continued sequence of lines) by extending its input buffer if
+necessary. This feature was broken for very long pattern lines, leading to
+a string of junk being passed to pcre_compile() if the pattern was longer
+than about 50K.
+17. I have done a major re-factoring of the way pcre_compile() computes the
+amount of memory needed for a compiled pattern. Previously, there was code
+that made a preliminary scan of the pattern in order to do this. That was
+OK when PCRE was new, but as the facilities have expanded, it has become
+harder and harder to keep it in step with the real compile phase, and there
+have been a number of bugs (see for example, 4 above). I have now found a
+cunning way of running the real compile function in a "fake" mode that
+enables it to compute how much memory it would need, while actually only
+ever using a few hundred bytes of working memory and without too many
+tests of the mode. This should make future maintenance and development
+easier. A side effect of this work is that the limit of 200 on the nesting
+depth of parentheses has been removed (though this was never a serious
+limitation, I suspect). However, there is a downside: pcre_compile() now
+runs more slowly than before (30% or more, depending on the pattern). I
+hope this isn't a big issue. There is no effect on runtime performance.
+18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
+newline (only possible for the last line of a file) and it was a
+pattern that set a locale (followed by /Lsomething), pcretest crashed.
+19. Added additional timing features to pcretest. (1) The -tm option now times
+matching only, not compiling. (2) Both -t and -tm can be followed, as a
+separate command line item, by a number that specifies the number of
+repeats to use when timing. The default is 50000; this gives better
+precision, but takes uncomfortably long for very large patterns.
+20. Extended pcre_study() to be more clever in cases where a branch of a
+subpattern has no definite first character. For example, (a*|b*)[cd] would
+previously give no result from pcre_study(). Now it recognizes that the
+first character must be a, b, c, or d.
+21. There was an incorrect error "recursive call could loop indefinitely" if
+a subpattern (or the entire pattern) that was being tested for matching an
+empty string contained only one non-empty item after a nested subpattern.
+For example, the pattern (?>\x{100}*)\d(?R) provoked this error
+incorrectly, because the \d was being skipped in the check.
+22. The pcretest program now has a new pattern option /B and a command line
+option -b, which is equivalent to adding /B to every pattern. This causes
+it to show the compiled bytecode, without the additional information that
+-d shows. The effect of -d is now the same as -b with -i (and similarly, /D
+is the same as /B/I).
+23. A new optimization is now able automatically to treat some sequences such
+as a*b as a*+b. More specifically, if something simple (such as a character
+or a simple class like \d) has an unlimited quantifier, and is followed by
+something that cannot possibly match the quantified thing, the quantifier
+is automatically "possessified".
+24. A recursive reference to a subpattern whose number was greater than 39
+went wrong under certain circumstances in UTF-8 mode. This bug could also
+have affected the operation of pcre_study().
+25. Realized that a little bit of performance could be had by replacing
+(c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
+26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
+27. Possessive quantifiers such as a++ were previously implemented by turning
+them into atomic groups such as ($>a+). Now they have their own opcodes,
+which improves performance. This includes the automatically created ones
+from 23 above.
+28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
+lookahead was broken if it was not anchored. PCRE was mistakenly expecting
+the first matched character to be a colon. This applied both to named and
+numbered groups.
+29. The ucpinternal.h header file was missing its idempotency #ifdef.
+30. I was sent a "project" file called libpcre.a.dev which I understand makes
+building PCRE on Windows easier, so I have included it in the distribution.
+31. There is now a check in pcretest against a ridiculously large number being
+returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
+loop, the loop is abandoned.
+32. Forward references to subpatterns in conditions such as (?(2)...) where
+subpattern 2 is defined later cause pcre_compile() to search forwards in
+the pattern for the relevant set of parentheses. This search went wrong
+when there were unescaped parentheses in a character class, parentheses
+escaped with \Q...\E, or parentheses in a #-comment in /x mode.
+33. "Subroutine" calls and backreferences were previously restricted to
+referencing subpatterns earlier in the regex. This restriction has now
+been removed.
+34. Added a number of extra features that are going to be in Perl 5.10. On the
+whole, these are just syntactic alternatives for features that PCRE had
+previously implemented using the Python syntax or my own invention. The
+other formats are all retained for compatibility.
+(a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
+as (?P<name>...). The new forms, as well as being in Perl 5.10, are
+also .NET compatible.
+(b) A recursion or subroutine call to a named group can now be defined as
+(?&name) as well as (?P>name).
+(c) A backreference to a named group can now be defined as \k<name> or
+\k'name' as well as (?P=name). The new forms, as well as being in Perl
+5.10, are also .NET compatible.
+(d) A conditional reference to a named group can now use the syntax
+(?(<name>) or (?('name') as well as (?(name).
+(e) A "conditional group" of the form (?(DEFINE)...) can be used to define
+groups (named and numbered) that are never evaluated inline, but can be
+called as "subroutines" from elsewhere. In effect, the DEFINE condition
+is always false. There may be only one alternative in such a group.
+(f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
+as the simple (?(R). The condition is true only if the most recent
+recursion is that of the given number or name. It does not search out
+through the entire recursion stack.
+(g) The escape \gN or \g{N} has been added, where N is a positive or
+negative number, specifying an absolute or relative reference.
+35. Tidied to get rid of some further signed/unsigned compiler warnings and
+some "unreachable code" warnings.
+36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
+things, this adds five new scripts.
+37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
+There were also incompatibilities regarding the handling of \Q..\E inside
+character classes, for example with patterns like [\Qa\E-\Qz\E] where the
+hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
+38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
+matches an empty string, and forcibly breaks the loop. There were bugs in
+this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
+against  aaaa  the result was just "a" rather than "aaaa", for example. Two
+separate and independent bugs (that affected different cases) have been
+fixed.
+39. Refactored the code to abolish the use of different opcodes for small
+capturing bracket numbers. This is a tidy that I avoided doing when I
+removed the limit on the number of capturing brackets for 3.5 back in 2001.
+The new approach is not only tidier, it makes it possible to reduce the
+memory needed to fix the previous bug (38).
+40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
+sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
+processing dot, circumflex, or dollar metacharacters, or #-comments in /x
+mode.
+41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
+report.
+42. Applied patch, originally from Ari Pollak, modified by Google, to allow
+copy construction and assignment in the C++ wrapper.
+43. Updated pcregrep to support "--newline=any". In the process, I fixed a
+couple of bugs that could have given wrong results in the "--newline=crlf"
+case.
+44. Added a number of casts and did some reorganization of signed/unsigned int
+variables following suggestions from Dair Grant. Also renamed the variable
+"this" as "item" because it is a C++ keyword.
+45. Arranged for dftables to add
+#include "pcre_internal.h"
+to pcre_chartables.c because without it, gcc 4.x may remove the array
+definition from the final binary if PCRE is built into a static library and
+dead code stripping is activated.
+46. For an unanchored pattern, if a match attempt fails at the start of a
+newline sequence, and the newline setting is CRLF or ANY, and the next two
+characters are CRLF, advance by two characters instead of one.
+Version 6.7 04-Jul-06
+---------------------
+1. In order to handle tests when input lines are enormously long, pcretest has
+been re-factored so that it automatically extends its buffers when
+necessary. The code is crude, but this _is_ just a test program. The
+default size has been increased from 32K to 50K.
+2. The code in pcre_study() was using the value of the re argument before
+testing it for NULL. (Of course, in any sensible call of the function, it
+won't be NULL.)
+3. The memmove() emulation function in pcre_internal.h, which is used on
+systems that lack both memmove() and bcopy() - that is, hardly ever -
+was missing a "static" storage class specifier.
+4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
+containing an extended class (one that cannot be represented by a bitmap
+because it contains high-valued characters or Unicode property items, e.g.
+[\pZ]). Almost always one would set UTF-8 mode when processing such a
+pattern, but PCRE should not loop if you do not (it no longer does).
+[Detail: two cases were found: (a) a repeated subpattern containing an
+extended class; (b) a recursive reference to a subpattern that followed a
+previous extended class. It wasn't skipping over the extended class
+correctly when UTF-8 mode was not set.]
+5. A negated single-character class was not being recognized as fixed-length
+in lookbehind assertions such as (?<=[^f]), leading to an incorrect
+compile error "lookbehind assertion is not fixed length".
+6. The RunPerlTest auxiliary script was showing an unexpected difference
+between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
+write a Perl script that can interpret lines of an input file either as
+byte characters or as UTF-8, which is what "perltest" was being required to
+do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
+can't do is switch easily at run time between having the "use utf8;" pragma
+or not. In the end, I fudged it by using the RunPerlTest script to insert
+"use utf8;" explicitly for the UTF-8 tests.
+7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
+the end of the subject string, contrary to the documentation and to what
+Perl does. This was true of both matching functions. Now it matches only at
+the start of the subject and immediately after *internal* newlines.
+8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
+a pointer to an int instead of a pointer to an unsigned long int. This
+caused problems on 64-bit systems.
+9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
+instance of the 'standard' template library not being so standard".
+10. There was no check on the number of named subpatterns nor the maximum
+length of a subpattern name. The product of these values is used to compute
+the size of the memory block for a compiled pattern. By supplying a very
+long subpattern name and a large number of named subpatterns, the size
+computation could be caused to overflow. This is now prevented by limiting
+the length of names to 32 characters, and the number of named subpatterns
+to 10,000.
+11. Subpatterns that are repeated with specific counts have to be replicated in
+the compiled pattern. The size of memory for this was computed from the
+length of the subpattern and the repeat count. The latter is limited to
+65535, but there was no limit on the former, meaning that integer overflow
+could in principle occur. The compiled length of a repeated subpattern is
+now limited to 30,000 bytes in order to prevent this.
+12. Added the optional facility to have named substrings with the same name.
+13. Added the ability to use a named substring as a condition, using the
+Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
+are numbers (not recommended). Forward references are permitted.
+14. Added forward references in named backreferences (if you see what I mean).
+15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
+pattern could run off the end of the subject. For example, the pattern
+"(?s)(.{1,5})"8 did this with the subject "ab".
+16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
+PCRE_CASELESS was set when matching characters that were quantified with ?
+or *.
+17. A character class other than a single negated character that had a minimum
+but no maximum quantifier - for example [ab]{6,} - was not handled
+correctly by pce_dfa_exec(). It would match only one character.
+18. A valid (though odd) pattern that looked like a POSIX character
+class but used an invalid character after [ (for example [[,abc,]]) caused
+pcre_compile() to give the error "Failed: internal error: code overflow" or
+in some cases to crash with a glibc free() error. This could even happen if
+the pattern terminated after [[ but there just happened to be a sequence of
+letters, a binary zero, and a closing ] in the memory that followed.
+19. Perl's treatment of octal escapes in the range \400 to \777 has changed
+over the years. Originally (before any Unicode support), just the bottom 8
+bits were taken. Thus, for example, \500 really meant \100. Nowadays the
+output from "man perlunicode" includes this:
+The regular expression compiler produces polymorphic opcodes.  That
+is, the pattern adapts to the data and automatically switches to
+the Unicode character scheme when presented with Unicode data--or
+instead uses a traditional byte scheme when presented with byte
+data.
+Sadly, a wide octal escape does not cause a switch, and in a string with
+no other multibyte characters, these octal escapes are treated as before.
+Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
+/\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
+Unicode string.
+I have not perpetrated such confusion in PCRE. Up till now, it took just
+the bottom 8 bits, as in old Perl. I have now made octal escapes with
+values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
+translate to the appropriate multibyte character.
+29. Applied some refactoring to reduce the number of warnings from Microsoft
+and Borland compilers. This has included removing the fudge introduced
+seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
+a warning about an unused variable.
+21. PCRE has not included VT (character 0x0b) in the set of whitespace
+characters since release 4.0, because Perl (from release 5.004) does not.
+[Or at least, is documented not to: some releases seem to be in conflict
+with the documentation.] However, when a pattern was studied with
+pcre_study() and all its branches started with \s, PCRE still included VT
+as a possible starting character. Of course, this did no harm; it just
+caused an unnecessary match attempt.
+22. Removed a now-redundant internal flag bit that recorded the fact that case
+dependency changed within the pattern. This was once needed for "required
+byte" processing, but is no longer used. This recovers a now-scarce options
+bit. Also moved the least significant internal flag bit to the most-
+significant bit of the word, which was not previously used (hangover from
+the days when it was an int rather than a uint) to free up another bit for
+the future.
+23. Added support for CRLF line endings as well as CR and LF. As well as the
+default being selectable at build time, it can now be changed at runtime
+via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
+specify that it is scanning data with non-default line endings.
+24. Changed the definition of CXXLINK to make it agree with the definition of
+LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
+25. Applied Ian Taylor's patches to avoid using another stack frame for tail
+recursions. This makes a big different to stack usage for some patterns.
+26. If a subpattern containing a named recursion or subroutine reference such
+as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
+the space required for the compiled pattern went wrong and gave too small a
+value. Depending on the environment, this could lead to "Failed: internal
+error: code overflow at offset 49" or "glibc detected double free or
+corruption" errors.
+27. Applied patches from Google (a) to support the new newline modes and (b) to
+advance over multibyte UTF-8 characters in GlobalReplace.
+28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
+difference for some implementation of PCRE in some Windows version.
+29. Added some extra testing facilities to pcretest:
+\q<number>   in a data line sets the "match limit" value
+\Q<number>   in a data line sets the "match recursion limt" value
+-S <number>  sets the stack size, where <number> is in megabytes
+The -S option isn't available for Windows.
+Version 6.6 06-Feb-06
+---------------------
+1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
+in pcreposix.h. I have copied the definition from pcre.h.
+2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
+because pcre.h is no longer a built file.
+3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
+not normally included in the compiled code.
+Version 6.5 01-Feb-06
+---------------------
+1. When using the partial match feature with pcre_dfa_exec(), it was not
+anchoring the second and subsequent partial matches at the new starting
+point. This could lead to incorrect results. For example, with the pattern
+/1234/, partially matching against "123" and then "a4" gave a match.
+2. Changes to pcregrep:
+(a) All non-match returns from pcre_exec() were being treated as failures
+to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
+error message is output. Some extra information is given for the
+PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
+probably the only errors that are likely to be caused by users (by
+specifying a regex that has nested indefinite repeats, for instance).
+If there are more than 20 of these errors, pcregrep is abandoned.
+(b) A binary zero was treated as data while matching, but terminated the
+output line if it was written out. This has been fixed: binary zeroes
+are now no different to any other data bytes.
+(c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
+used to set a locale for matching. The --locale=xxxx long option has
+been added (no short equivalent) to specify a locale explicitly on the
+pcregrep command, overriding the environment variables.
+(d) When -B was used with -n, some line numbers in the output were one less
+than they should have been.
+(e) Added the -o (--only-matching) option.
+(f) If -A or -C was used with -c (count only), some lines of context were
+accidentally printed for the final match.
+(g) Added the -H (--with-filename) option.
+(h) The combination of options -rh failed to suppress file names for files
+that were found from directory arguments.
+(i) Added the -D (--devices) and -d (--directories) options.
+(j) Added the -F (--fixed-strings) option.
+(k) Allow "-" to be used as a file name for -f as well as for a data file.
+(l) Added the --colo(u)r option.
+(m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
+is not present by default.
+3. A nasty bug was discovered in the handling of recursive patterns, that is,
+items such as (?R) or (?1), when the recursion could match a number of
+alternatives. If it matched one of the alternatives, but subsequently,
+outside the recursion, there was a failure, the code tried to back up into
+the recursion. However, because of the way PCRE is implemented, this is not
+possible, and the result was an incorrect result from the match.
+In order to prevent this happening, the specification of recursion has
+been changed so that all such subpatterns are automatically treated as
+atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
+4. I had overlooked the fact that, in some locales, there are characters for
+which isalpha() is true but neither isupper() nor islower() are true. In
+the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
+and ordfeminine) are like this. This affected the treatment of \w and \W
+when they appeared in character classes, but not when they appeared outside
+a character class. The bit map for "word" characters is now created
+separately from the results of isalnum() instead of just taking it from the
+upper, lower, and digit maps. (Plus the underscore character, of course.)
+5. The above bug also affected the handling of POSIX character classes such as
+[[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
+permanent tables. Instead, the bit maps for such a class were previously
+created as the appropriate unions of the upper, lower, and digit bitmaps.
+Now they are created by subtraction from the [[:word:]] class, which has
+its own bitmap.
+6. The [[:blank:]] character class matches horizontal, but not vertical space.
+It is created by subtracting the vertical space characters (\x09, \x0a,
+\x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
+subtraction was done in the overall bitmap for a character class, meaning
+that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
+be recognized. This bug has been fixed.
+7. Patches from the folks at Google:
+(a) pcrecpp.cc: "to handle a corner case that may or may not happen in
+real life, but is still worth protecting against".
+(b) pcrecpp.cc: "corrects a bug when negative radixes are used with
+regular expressions".
+(c) pcre_scanner.cc: avoid use of std::count() because not all systems
+have it.
+(d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
+"configure" and the latter not, in order to fix a problem somebody had
+with compiling the Arg class on HP-UX.
+(e) Improve the error-handling of the C++ wrapper a little bit.
+(f) New tests for checking recursion limiting.
+8. The pcre_memmove() function, which is used only if the environment does not
+have a standard memmove() function (and is therefore rarely compiled),
+contained two bugs: (a) use of int instead of size_t, and (b) it was not
+returning a result (though PCRE never actually uses the result).
+9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
+large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
+returned instead of calling malloc() with an overflowing number that would
+most likely cause subsequent chaos.
+10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
+11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
+with this option is matched, the nmatch and pmatch options of regexec() are
+ignored.
+12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
+provided in case anyone wants to the the POSIX interface with UTF-8
+strings.
+13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
+C++ linking (needed for some HP-UX environments).
+14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
+(unused parameter) and in the pcre_printint() function (omitted "default"
+switch label when the default is to do nothing).
+15. Added some code to make it possible, when PCRE is compiled as a C++
+library, to replace subject pointers for pcre_exec() with a smart pointer
+class, thus making it possible to process discontinuous strings.
+16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
+much the same function. They were added by different people who were trying
+to make PCRE easy to compile on non-Unix systems. It has been suggested
+that PCRE_EXPORT be abolished now that there is more automatic apparatus
+for compiling on Windows systems. I have therefore replaced it with
+PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
+defaults to "extern" for C or "extern C" for C++, which works fine on
+Unix-like systems. It is now possible to override the value of PCRE_DATA_
+SCOPE with something explicit in config.h. In addition:
+(a) pcreposix.h still had just "extern" instead of either of these macros;
+I have replaced it with PCRE_DATA_SCOPE.
+(b) Functions such as _pcre_xclass(), which are internal to the library,
+but external in the C sense, all had PCRE_EXPORT in their definitions.
+This is apparently wrong for the Windows case, so I have removed it.
+(It makes no difference on Unix-like systems.)
+17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
+of recursive calls to match(). This is different to MATCH_LIMIT because
+that limits the total number of calls to match(), not all of which increase
+the depth of recursion. Limiting the recursion depth limits the amount of
+stack (or heap if NO_RECURSE is set) that is used. The default can be set
+when PCRE is compiled, and changed at run time. A patch from Google adds
+this functionality to the C++ interface.
+18. Changes to the handling of Unicode character properties:
+(a) Updated the table to Unicode 4.1.0.
+(b) Recognize characters that are not in the table as "Cn" (undefined).
+(c) I revised the way the table is implemented to a much improved format
+which includes recognition of ranges. It now supports the ranges that
+are defined in UnicodeData.txt, and it also amalgamates other
+characters into ranges. This has reduced the number of entries in the
+table from around 16,000 to around 3,000, thus reducing its size
+considerably. I realized I did not need to use a tree structure after
+all - a binary chop search is just as efficient. Having reduced the
+number of entries, I extended their size from 6 bytes to 8 bytes to
+allow for more data.
+(d) Added support for Unicode script names via properties such as \p{Han}.
+19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
+matching that character.
+20. When matching a repeated Unicode property with a minimum greater than zero,
+(for example \pL{2,}), PCRE could look past the end of the subject if it
+reached it while seeking the minimum number of characters. This could
+happen only if some of the characters were more than one byte long, because
+there is a check for at least the minimum number of bytes.
+21. Refactored the implementation of \p and \P so as to be more general, to
+allow for more different types of property in future. This has changed the
+compiled form incompatibly. Anybody with saved compiled patterns that use
+\p or \P will have to recompile them.
+22. Added "Any" and "L&" to the supported property types.
+23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
+but give a compile time error if the value is greater than 0xff.
+24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
+accidentally not being installed or uninstalled.
+25. The pcre.h file was built from pcre.h.in, but the only changes that were
+made were to insert the current release number. This seemed silly, because
+it made things harder for people building PCRE on systems that don't run
+"configure". I have turned pcre.h into a distributed file, no longer built
+by "configure", with the version identification directly included. There is
+no longer a pcre.h.in file.
+However, this change necessitated a change to the pcre-config script as
+well. It is built from pcre-config.in, and one of the substitutions was the
+release number. I have updated configure.ac so that ./configure now finds
+the release number by grepping pcre.h.
+26. Added the ability to run the tests under valgrind.
+Version 6.4 05-Sep-05
+---------------------
+1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
+"--" to be printed when multiple files were scanned, even when none of the
+-A, -B, or -C options were used. This is not compatible with Gnu grep, so I
+consider it to be a bug, and have restored the previous behaviour.
+2. A couple of code tidies to get rid of compiler warnings.
+3. The pcretest program used to cheat by referring to symbols in the library
+whose names begin with _pcre_. These are internal symbols that are not
+really supposed to be visible externally, and in some environments it is
+possible to suppress them. The cheating is now confined to including
+certain files from the library's source, which is a bit cleaner.
+4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
+file's purpose clearer.
+5. Reorganized pcre_ucp_findchar().
+Version 6.3 15-Aug-05
+---------------------
+1. The file libpcre.pc.in did not have general read permission in the tarball.
+2. There were some problems when building without C++ support:
+(a) If C++ support was not built, "make install" and "make test" still
+tried to test it.
+(b) There were problems when the value of CXX was explicitly set. Some
+changes have been made to try to fix these, and ...
+(c) --disable-cpp can now be used to explicitly disable C++ support.
+(d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
+backslash in a target when C++ was disabled. This confuses some
+versions of "make", apparently. Using an intermediate variable solves
+this. (Same for CPP_LOBJ.)
+3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
+(non-Windows) now includes $(CFLAGS) because these flags are sometimes
+necessary on certain architectures.
+4. Added a setting of -export-symbols-regex to the link command to remove
+those symbols that are exported in the C sense, but actually are local
+within the library, and not documented. Their names all begin with
+"_pcre_". This is not a perfect job, because (a) we have to except some
+symbols that pcretest ("illegally") uses, and (b) the facility isn't always
+available (and never for static libraries). I have made a note to try to
+find a way round (a) in the future.
+Version 6.2 01-Aug-05
+---------------------
+1. There was no test for integer overflow of quantifier values. A construction
+such as {1111111111111111} would give undefined results. What is worse, if
+a minimum quantifier for a parenthesized subpattern overflowed and became
+negative, the calculation of the memory size went wrong. This could have
+led to memory overwriting.
+2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
+3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
+operating environments where this matters.
+4. Applied Giuseppe Maxia's patch to add additional features for controlling
+PCRE options from within the C++ wrapper.
+5. Named capturing subpatterns were not being correctly counted when a pattern
+was compiled. This caused two problems: (a) If there were more than 100
+such subpatterns, the calculation of the memory needed for the whole
+compiled pattern went wrong, leading to an overflow error. (b) Numerical
+back references of the form \12, where the number was greater than 9, were
+not recognized as back references, even though there were sufficient
+previous subpatterns.
+6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
+versions of gcc, e.g. 2.95.4.
+Version 6.1 21-Jun-05
+---------------------
+1. There was one reference to the variable "posix" in pcretest.c that was not
+surrounded by "#if !defined NOPOSIX".
+2. Make it possible to compile pcretest without DFA support, UTF8 support, or
+the cross-check on the old pcre_info() function, for the benefit of the
+cut-down version of PCRE that is currently imported into Exim.
+3. A (silly) pattern starting with (?i)(?-i) caused an internal space
+allocation error. I've done the easy fix, which wastes 2 bytes for sensible
+patterns that start (?i) but I don't think that matters. The use of (?i) is
+just an example; this all applies to the other options as well.
+4. Since libtool seems to echo the compile commands it is issuing, the output
+from "make" can be reduced a bit by putting "@" in front of each libtool
+compile command.
+5. Patch from the folks at Google for configure.in to be a bit more thorough
+in checking for a suitable C++ installation before trying to compile the
+C++ stuff. This should fix a reported problem when a compiler was present,
+but no suitable headers.
+6. The man pages all had just "PCRE" as their title. I have changed them to
+be the relevant file name. I have also arranged that these names are
+retained in the file doc/pcre.txt, which is a concatenation in text format
+of all the man pages except the little individual ones for each function.
+7. The NON-UNIX-USE file had not been updated for the different set of source
+files that come with release 6. I also added a few comments about the C++
+wrapper.
+Version 6.0 07-Jun-05
+---------------------
+1. Some minor internal re-organization to help with my DFA experiments.
+2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
+didn't matter for the library itself when fully configured, but did matter
+when compiling without UCP support, or within Exim, where the ucp files are
+not imported.
+3. Refactoring of the library code to split up the various functions into
+different source modules. The addition of the new DFA matching code (see
+below) to a single monolithic source would have made it really too
+unwieldy, quite apart from causing all the code to be include in a
+statically linked application, when only some functions are used. This is
+relevant even without the DFA addition now that patterns can be compiled in
+one application and matched in another.
+The downside of splitting up is that there have to be some external
+functions and data tables that are used internally in different modules of
+the library but which are not part of the API. These have all had their
+names changed to start with "_pcre_" so that they are unlikely to clash
+with other external names.
+4. Added an alternate matching function, pcre_dfa_exec(), which matches using
+a different (DFA) algorithm. Although it is slower than the original
+function, it does have some advantages for certain types of matching
+problem.
+5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
+including restarting after a partial match.
+6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
+defined when compiling for Windows was sent to me. I have put it into the
+code, though I have no means of testing or verifying it.
+7. Added the pcre_refcount() auxiliary function.
+8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
+match before or at the first newline in the subject string. In pcretest,
+the /f option on a pattern can be used to set this.
+9. A repeated \w when used in UTF-8 mode with characters greater than 256
+would behave wrongly. This has been present in PCRE since release 4.0.
+10. A number of changes to the pcregrep command:
+(a) Refactored how -x works; insert ^(...)$ instead of setting
+PCRE_ANCHORED and checking the length, in preparation for adding
+something similar for -w.
+(b) Added the -w (match as a word) option.
+(c) Refactored the way lines are read and buffered so as to have more
+than one at a time available.
+(d) Implemented a pcregrep test script.
+(e) Added the -M (multiline match) option. This allows patterns to match
+over several lines of the subject. The buffering ensures that at least
+8K, or the rest of the document (whichever is the shorter) is available
+for matching (and similarly the previous 8K for lookbehind assertions).
+(f) Changed the --help output so that it now says
+-w, --word-regex(p)
+instead of two lines, one with "regex" and the other with "regexp"
+because that confused at least one person since the short forms are the
+same. (This required a bit of code, as the output is generated
+automatically from a table. It wasn't just a text change.)
+(g) -- can be used to terminate pcregrep options if the next thing isn't an
+option but starts with a hyphen. Could be a pattern or a path name
+starting with a hyphen, for instance.
+(h) "-" can be given as a file name to represent stdin.
+(i) When file names are being printed, "(standard input)" is used for
+the standard input, for compatibility with GNU grep. Previously
+"<stdin>" was used.
+(j) The option --label=xxx can be used to supply a name to be used for
+stdin when file names are being printed. There is no short form.
+(k) Re-factored the options decoding logic because we are going to add
+two more options that take data. Such options can now be given in four
+different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
+(l) Added the -A, -B, and -C options for requesting that lines of context
+around matches be printed.
+(m) Added the -L option to print the names of files that do not contain
+any matching lines, that is, the complement of -l.
+(n) The return code is 2 if any file cannot be opened, but pcregrep does
+continue to scan other files.
+(o) The -s option was incorrectly implemented. For compatibility with other
+greps, it now suppresses the error message for a non-existent or non-
+accessible file (but not the return code). There is a new option called
+-q that suppresses the output of matching lines, which was what -s was
+previously doing.
+(p) Added --include and --exclude options to specify files for inclusion
+and exclusion when recursing.
+11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
+Hopefully, it now does.
+12. Missing cast in pcre_study().
+13. Added an "uninstall" target to the makefile.
+14. Replaced "extern" in the function prototypes in Makefile.in with
+"PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
+world, but is set differently for Windows.
+15. Added a second compiling function called pcre_compile2(). The only
+difference is that it has an extra argument, which is a pointer to an
+integer error code. When there is a compile-time failure, this is set
+non-zero, in addition to the error test pointer being set to point to an
+error message. The new argument may be NULL if no error number is required
+(but then you may as well call pcre_compile(), which is now just a
+wrapper). This facility is provided because some applications need a
+numeric error indication, but it has also enabled me to tidy up the way
+compile-time errors are handled in the POSIX wrapper.
+16. Added VPATH=.libs to the makefile; this should help when building with one
+prefix path and installing with another. (Or so I'm told by someone who
+knows more about this stuff than I do.)
+17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
+passes PCRE_DOTALL to the pcre_compile() function, making the "." character
+match everything, including newlines. This is not POSIX-compatible, but
+somebody wanted the feature. From pcretest it can be activated by using
+both the P and the s flags.
+18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
+19. libpcre.pc was being incorrectly installed as executable.
+20. A couple of places in pcretest check for end-of-line by looking for '\n';
+it now also looks for '\r' so that it will work unmodified on Windows.
+21. Added Google's contributed C++ wrapper to the distribution.
+22. Added some untidy missing memory free() calls in pcretest, to keep
+Electric Fence happy when testing.
+Version 5.0 13-Sep-04
+---------------------
+1. Internal change: literal characters are no longer packed up into items
+containing multiple characters in a single byte-string. Each character
+is now matched using a separate opcode. However, there may be more than one
+byte in the character in UTF-8 mode.
+2. The pcre_callout_block structure has two new fields: pattern_position and
+next_item_length. These contain the offset in the pattern to the next match
+item, and its length, respectively.
+3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
+insertion of callouts before each pattern item. Added the /C option to
+pcretest to make use of this.
+4. On the advice of a Windows user, the lines
+#if defined(_WIN32) || defined(WIN32)
+_setmode( _fileno( stdout ), 0x8000 );
+#endif  /* defined(_WIN32) || defined(WIN32) */
+have been added to the source of pcretest. This apparently does useful
+magic in relation to line terminators.
+5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
+for the benefit of those environments where the "b" makes a difference.
+6. The icc compiler has the same options as gcc, but "configure" doesn't seem
+to know about it. I have put a hack into configure.in that adds in code
+to set GCC=yes if CC=icc. This seems to end up at a point in the
+generated configure script that is early enough to affect the setting of
+compiler options, which is what is needed, but I have no means of testing
+whether it really works. (The user who reported this had patched the
+generated configure script, which of course I cannot do.)
+LATER: After change 22 below (new libtool files), the configure script
+seems to know about icc (and also ecc). Therefore, I have commented out
+this hack in configure.in.
+7. Added support for pkg-config (2 patches were sent in).
+8. Negated POSIX character classes that used a combination of internal tables
+were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
+[[:^ascii]]. Typically, they would match almost any characters. The other
+POSIX classes were not broken in this way.
+9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
+to find the match, as PCRE was deluded into thinking that the match had to
+start at the start point or following a newline. The same bug applied to
+patterns with negative forward assertions or any backward assertions
+preceding ".*" at the start, unless the pattern required a fixed first
+character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
+10. In UTF-8 mode, when moving forwards in the subject after a failed match
+starting at the last subject character, bytes beyond the end of the subject
+string were read.
+11. Renamed the variable "class" as "classbits" to make life easier for C++
+users. (Previously there was a macro definition, but it apparently wasn't
+enough.)
+12. Added the new field "tables" to the extra data so that tables can be passed
+in at exec time, or the internal tables can be re-selected. This allows
+a compiled regex to be saved and re-used at a later time by a different
+program that might have everything at different addresses.
+13. Modified the pcre-config script so that, when run on Solaris, it shows a
+-R library as well as a -L library.
+14. The debugging options of pcretest (-d on the command line or D on a
+pattern) showed incorrect output for anything following an extended class
+that contained multibyte characters and which was followed by a quantifier.
+15. Added optional support for general category Unicode character properties
+via the \p, \P, and \X escapes. Unicode property support implies UTF-8
+support. It adds about 90K to the size of the library. The meanings of the
+inbuilt class escapes such as \d and \s have NOT been changed.
+16. Updated pcredemo.c to include calls to free() to release the memory for the
+compiled pattern.
+17. The generated file chartables.c was being created in the source directory
+instead of in the building directory. This caused the build to fail if the
+source directory was different from the building directory, and was
+read-only.
+18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
+file. No doubt somebody will tell me if they don't make sense... Also added
+Dan Mooney's comments about building on OpenVMS.
+19. Added support for partial matching via the PCRE_PARTIAL option for
+pcre_exec() and the \P data escape in pcretest.
+20. Extended pcretest with 3 new pattern features:
+(i)   A pattern option of the form ">rest-of-line" causes pcretest to
+write the compiled pattern to the file whose name is "rest-of-line".
+This is a straight binary dump of the data, with the saved pointer to
+the character tables forced to be NULL. The study data, if any, is
+written too. After writing, pcretest reads a new pattern.
+(ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
+compiled pattern from the given file. There must not be any
+occurrences of "<" in the file name (pretty unlikely); if there are,
+pcretest will instead treat the initial "<" as a pattern delimiter.
+After reading in the pattern, pcretest goes on to read data lines as
+usual.
+(iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
+and 16-bit fields in a compiled pattern, to simulate a pattern that
+was compiled on a host of opposite endianness.
+21. The pcre-exec() function can now cope with patterns that were compiled on
+hosts of opposite endianness, with this restriction:
+As for any compiled expression that is saved and used later, the tables
+pointer field cannot be preserved; the extra_data field in the arguments
+to pcre_exec() should be used to pass in a tables address if a value
+other than the default internal tables were used at compile time.
+22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
+now diagnosed as an error. Previously, most of the time, a negative number
+would have been treated as zero, but if in addition "ovector" was passed as
+NULL, a crash could occur.
+23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
+new versions from the libtool 1.5 distribution (the last one is a copy of
+a file called libtool.m4). This seems to have fixed the need to patch
+"configure" to support Darwin 1.3 (which I used to do). However, I still
+had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
+workstation).
+24. Changed the PCRE licence to be the more standard "BSD" licence.
+Version 4.5 01-Dec-03
+---------------------
+1. There has been some re-arrangement of the code for the match() function so
+that it can be compiled in a version that does not call itself recursively.
+Instead, it keeps those local variables that need separate instances for
+each "recursion" in a frame on the heap, and gets/frees frames whenever it
+needs to "recurse". Keeping track of where control must go is done by means
+of setjmp/longjmp. The whole thing is implemented by a set of macros that
+hide most of the details from the main code, and operates only if
+NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
+"configure" mechanism, "--disable-stack-for-recursion" turns on this way of
+operating.
+To make it easier for callers to provide specially tailored get/free
+functions for this usage, two new functions, pcre_stack_malloc, and
+pcre_stack_free, are used. They are always called in strict stacking order,
+and the size of block requested is always the same.
+The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
+PCRE has been compiled to use the stack or the heap for recursion. The
+-C option of pcretest uses this to show which version is compiled.
+A new data escape \S, is added to pcretest; it causes the amounts of store
+obtained and freed by both kinds of malloc/free at match time to be added
+to the output.
+2. Changed the locale test to use "fr_FR" instead of "fr" because that's
+what's available on my current Linux desktop machine.
+3. When matching a UTF-8 string, the test for a valid string at the start has
+been extended. If start_offset is not zero, PCRE now checks that it points
+to a byte that is the start of a UTF-8 character. If not, it returns
+PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
+this is necessary because there may be backward assertions in the pattern.
+When matching the same subject several times, it may save resources to use
+PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
+4. The code for checking the validity of UTF-8 strings has been tightened so
+that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
+containing "overlong sequences".
+5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
+I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
+should have been "&", but it just so happened that all the cases this let
+through by mistake were picked up later in the function.
+6. I had used a variable called "isblank" - this is a C99 function, causing
+some compilers to warn. To avoid this, I renamed it (as "blankclass").
+7. Cosmetic: (a) only output another newline at the end of pcretest if it is
+prompting; (b) run "./pcretest /dev/null" at the start of the test script
+so the version is shown; (c) stop "make test" echoing "./RunTest".
+8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
+9. The prototype for memmove() for systems that don't have it was using
+size_t, but the inclusion of the header that defines size_t was later. I've
+moved the #includes for the C headers earlier to avoid this.
+10. Added some adjustments to the code to make it easier to compiler on certain
+special systems:
+(a) Some "const" qualifiers were missing.
+(b) Added the macro EXPORT before all exported functions; by default this
+is defined to be empty.
+(c) Changed the dftables auxiliary program (that builds chartables.c) so
+that it reads its output file name as an argument instead of writing
+to the standard output and assuming this can be redirected.
+11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
+class containing characters with values greater than 255, PCRE compilation
+went into a loop.
+12. A recursive reference to a subpattern that was within another subpattern
+that had a minimum quantifier of zero caused PCRE to crash. For example,
+(x(y(?2))z)? provoked this bug with a subject that got as far as the
+recursion. If the recursively-called subpattern itself had a zero repeat,
+that was OK.
+13. In pcretest, the buffer for reading a data line was set at 30K, but the
+buffer into which it was copied (for escape processing) was still set at
+1024, so long lines caused crashes.
+14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
+"internal error: code overflow...". This applied to any character class
+that was followed by a possessive quantifier.
+15. Modified the Makefile to add libpcre.la as a prerequisite for
+libpcreposix.la because I was told this is needed for a parallel build to
+work.
+16. If a pattern that contained .* following optional items at the start was
+studied, the wrong optimizing data was generated, leading to matching
+errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
+matching string must start with a or b or c. The correct conclusion for
+this pattern is that a match can start with any character.
+Version 4.4 13-Aug-03
+---------------------
+1. In UTF-8 mode, a character class containing characters with values between
+127 and 255 was not handled correctly if the compiled pattern was studied.
+In fixing this, I have also improved the studying algorithm for such
+classes (slightly).
+2. Three internal functions had redundant arguments passed to them. Removal
+might give a very teeny performance improvement.
+3. Documentation bug: the value of the capture_top field in a callout is *one
+more than* the number of the hightest numbered captured substring.
+4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
+in incorrectly linking with a previously installed version. They now link
+explicitly with libpcre.la.
+5. configure.in no longer needs to recognize Cygwin specially.
+6. A problem in pcre.in for Windows platforms is fixed.
+7. If a pattern was successfully studied, and the -d (or /D) flag was given to
+pcretest, it used to include the size of the study block as part of its
+output. Unfortunately, the structure contains a field that has a different
+size on different hardware architectures. This meant that the tests that
+showed this size failed. As the block is currently always of a fixed size,
+this information isn't actually particularly useful in pcretest output, so
+I have just removed it.
+8. Three pre-processor statements accidentally did not start in column 1.
+Sadly, there are *still* compilers around that complain, even though
+standard C has not required this for well over a decade. Sigh.
+9. In pcretest, the code for checking callouts passed small integers in the
+callout_data field, which is a void * field. However, some picky compilers
+complained about the casts involved for this on 64-bit systems. Now
+pcretest passes the address of the small integer instead, which should get
+rid of the warnings.
+10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
+both compile and run time, and gives an error if an invalid UTF-8 sequence
+is found. There is a option for disabling this check in cases where the
+string is known to be correct and/or the maximum performance is wanted.
+11. In response to a bug report, I changed one line in Makefile.in from
+-Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
+to
+-Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
+to look similar to other lines, but I have no way of telling whether this
+is the right thing to do, as I do not use Windows. No doubt I'll get told
+if it's wrong...
+Version 4.3 21-May-03
+---------------------
+1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
+Makefile.
+2. Some refactoring to improve the quality of the code:
+(i)   The utf8_table... variables are now declared "const".
+(ii)  The code for \cx, which used the "case flipping" table to upper case
+lower case letters, now just substracts 32. This is ASCII-specific,
+but the whole concept of \cx is ASCII-specific, so it seems
+reasonable.
+(iii) PCRE was using its character types table to recognize decimal and
+hexadecimal digits in the pattern. This is silly, because it handles
+only 0-9, a-f, and A-F, but the character types table is locale-
+specific, which means strange things might happen. A private
+table is now used for this - though it costs 256 bytes, a table is
+much faster than multiple explicit tests. Of course, the standard
+character types table is still used for matching digits in subject
+strings against \d.
+(iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
+ending in _t are). So I've renamed it as ESC_tee.
+3. The first argument for regexec() in the POSIX wrapper should have been
+defined as "const".
+4. Changed pcretest to use malloc() for its buffers so that they can be
+Electric Fenced for debugging.
+5. There were several places in the code where, in UTF-8 mode, PCRE would try
+to read one or more bytes before the start of the subject string. Often this
+had no effect on PCRE's behaviour, but in some circumstances it could
+provoke a segmentation fault.
+6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
+to try to read one or more bytes before the start of the subject string.
+7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
+UTF-8 support could misbehave in various ways if the subject string
+contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
+area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
+back over UTF-8 characters.)
+Version 4.2 14-Apr-03
+---------------------
+1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
+2. Changes to the building process, supplied by Ronald Landheer-Cieslak
+[ON_WINDOWS]: new variable, "#" on non-Windows platforms
+[NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
+[WIN_PREFIX]: new variable, "cyg" for Cygwin
+* Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
+and BUILD_EXEEXT
+Note: automatic setting of the BUILD variables is not yet working
+set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
+compile-time but not at link-time
+[LINK]: use for linking executables only
+make different versions for Windows and non-Windows
+[LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
+libraries
+[LINK_FOR_BUILD]: new variable
+[OBJEXT]: use throughout
+[EXEEXT]: use throughout
+<winshared>: new target
+<wininstall>: new target
+<dftables.o>: use native compiler
+<dftables>: use native linker
+<install>: handle Windows platform correctly
+<clean>: ditto
+<check>: ditto
+copy DLL to top builddir before testing
+As part of these changes, -no-undefined was removed again. This was reported
+to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
+in any case.
+3. Some tidies to get rid of compiler warnings:
+. In the match_data structure, match_limit was an unsigned long int, whereas
+match_call_count was an int. I've made them both unsigned long ints.
+. In pcretest the fact that a const uschar * doesn't automatically cast to
+a void * provoked a warning.
+. Turning on some more compiler warnings threw up some "shadow" variables
+and a few more missing casts.
+4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
+option, a class that contained a single character with a value between 128
+and 255 (e.g. /[\xFF]/) caused PCRE to crash.
+5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
+option, a class that contained several characters, but with at least one
+whose value was between 128 and 255 caused PCRE to crash.
+Version 4.1 12-Mar-03
+---------------------
+1. Compiling with gcc -pedantic found a couple of places where casts were
+needed, and a string in dftables.c that was longer than standard compilers are
+required to support.
+2. Compiling with Sun's compiler found a few more places where the code could
+be tidied up in order to avoid warnings.
+3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
+first of these names is deprecated in the latest Autoconf in favour of the name
+CC_FOR_BUILD, because "host" is typically used to mean the system on which the
+compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
+analogy I have changed it to CFLAGS_FOR_BUILD.
+4. Added -no-undefined to the linking command in the Makefile, because this is
+apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
+linking step for the pcreposix library.
+5. PCRE was failing to diagnose the case of two named groups with the same
+name.
+6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
+literal character that is needed in the subject for a match, and scans along to
+ensure that it is present before embarking on the full matching process. This
+saves time in cases of nested unlimited repeats that are never going to match.
+Problem: the scan can take a lot of time if the subject is very long (e.g.
+megabytes), thus penalizing straightforward matches. It is now done only if the
+amount of subject to be scanned is less than 1000 bytes.
+7. A lesser problem with the same optimization is that it was recording the
+first character of an anchored pattern as "needed", thus provoking a search
+right along the subject, even when the first match of the pattern was going to
+fail. The "needed" character is now not set for anchored patterns, unless it
+follows something in the pattern that is of non-fixed length. Thus, it still
+fulfils its original purpose of finding quick non-matches in cases of nested
+unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
+Version 4.0 17-Feb-03
+---------------------
+1. If a comment in an extended regex that started immediately after a meta-item
+extended to the end of string, PCRE compiled incorrect data. This could lead to
+all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
+2. Moved to autoconf 2.53 and libtool 1.4.2.
+3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
+the special perltest8 script is no longer needed - all the tests can be run
+from a single perltest script.
+4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
+by \s. It has now been removed in PCRE. This means it isn't recognized as
+whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
+class [:space:] *does* include VT, thereby creating a mess.
+5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
+space and tab.
+6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
+its new features into the main test script, reducing the number of scripts.
+7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
+were backward compatible, and made the (?i) apply to the whole pattern, as if
+/i were given. Now it behaves more logically, and applies the option setting
+only to what follows. PCRE has been changed to follow suit. However, if it
+finds options settings right at the start of the pattern, it extracts them into
+the global options, as before. Thus, they show up in the info data.
+8. Added support for the \Q...\E escape sequence. Characters in between are
+treated as literals. This is slightly different from Perl in that $ and @ are
+also handled as literals inside the quotes. In Perl, they will cause variable
+interpolation. Note the following examples:
+Pattern            PCRE matches      Perl matches
+\Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
+\Qabc\$xyz\E       abc\$xyz          abc\$xyz
+\Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
+For compatibility with Perl, \Q...\E sequences are recognized inside character
+classes as well as outside them.
+9. Re-organized 3 code statements in pcretest to avoid "overflow in
+floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
+(size_t) cast to one statement in pcretest and one in pcreposix to avoid
+signed/unsigned warnings.
+10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
+option for pcretest, so I've replaced it by a simple function that does just
+that job.
+11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
+"pcregrep -".
+12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
+Java package. This provides some syntactic sugar for simple cases of what my
+documentation calls "once-only subpatterns". A pattern such as x*+ is the same
+as (?>x*). In other words, if what is inside (?>...) is just a single repeated
+item, you can use this simplified notation. Note that only makes sense with
+greedy quantifiers. Consequently, the use of the possessive quantifier forces
+greediness, whatever the setting of the PCRE_UNGREEDY option.
+13. A change of greediness default within a pattern was not taking effect at
+the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
+subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
+was abstracted outside.
+14. PCRE now supports the \G assertion. It is true when the current matching
+position is at the start point of the match. This differs from \A when the
+starting offset is non-zero. Used with the /g option of pcretest (or similar
+code), it works in the same way as it does for Perl's /g option. If all
+alternatives of a regex begin with \G, the expression is anchored to the start
+match position, and the "anchored" flag is set in the compiled expression.
+15. Some bugs concerning the handling of certain option changes within patterns
+have been fixed. These applied to options other than (?ims). For example,
+"a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
+been the other way round. Some of this was related to change 7 above.
+16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
+features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
+and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
+POSIX classes only within a class (e.g. /[[:alpha:]]/).
+17. Added support for Perl's \C escape. This matches one byte, even in UTF8
+mode. Unlike ".", it always matches newline, whatever the setting of
+PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
+assertions. Perl allows it, but it doesn't (in general) work because it can't
+calculate the length of the lookbehind. At least, that's the case for Perl
+5.8.0 - I've been told they are going to document that it doesn't work in
+future.
+18. Added an error diagnosis for escapes that PCRE does not support: these are
+\L, \l, \N, \P, \p, \U, \u, and \X.
+19. Although correctly diagnosing a missing ']' in a character class, PCRE was
+reading past the end of the pattern in cases such as /[abcd/.
+20. PCRE was getting more memory than necessary for patterns with classes that
+contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
+21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
+compiling PCRE for use with Virtual Pascal.
+22. Small fix to the Makefile to make it work properly if the build is done
+outside the source tree.
+23. Added a new extension: a condition to go with recursion. If a conditional
+subpattern starts with (?(R) the "true" branch is used if recursion has
+happened, whereas the "false" branch is used only at the top level.
+24. When there was a very long string of literal characters (over 255 bytes
+without UTF support, over 250 bytes with UTF support), the computation of how
+much memory was required could be incorrect, leading to segfaults or other
+strange effects.
+25. PCRE was incorrectly assuming anchoring (either to start of subject or to
+start of line for a non-DOTALL pattern) when a pattern started with (.*) and
+there was a subsequent back reference to those brackets. This meant that, for
+example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
+possible to check for precisely this case. All we can do is abandon the
+optimization if .* occurs inside capturing brackets when there are any back
+references whatsoever. (See below for a better fix that came later.)
+26. The handling of the optimization for finding the first character of a
+non-anchored pattern, and for finding a character that is required later in the
+match were failing in some cases. This didn't break the matching; it just
+failed to optimize when it could. The way this is done has been re-implemented.
+27. Fixed typo in error message for invalid (?R item (it said "(?p").
+28. Added a new feature that provides some of the functionality that Perl
+provides with (?{...}). The facility is termed a "callout". The way it is done
+in PCRE is for the caller to provide an optional function, by setting
+pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
+global variable. By default it is unset, which disables all calling out. To get
+the function called, the regex must include (?C) at appropriate points. This
+is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
+This provides a means of identifying different callout points. When PCRE
+reaches such a point in the regex, if pcre_callout has been set, the external
+function is called. It is provided with data in a structure called
+pcre_callout_block, which is defined in pcre.h. If the function returns 0,
+matching continues; if it returns a non-zero value, the match at the current
+point fails. However, backtracking will occur if possible. [This was changed
+later and other features added - see item 49 below.]
+29. pcretest is upgraded to test the callout functionality. It provides a
+callout function that displays information. By default, it shows the start of
+the match and the current position in the text. There are some new data escapes
+to vary what happens:
+\C+         in addition, show current contents of captured substrings
+\C-         do not supply a callout function
+\C!n        return 1 when callout number n is reached
+\C!n!m      return 1 when callout number n is reached for the mth time
+30. If pcregrep was called with the -l option and just a single file name, it
+output "<stdin>" if a match was found, instead of the file name.
+31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
+slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
+pcre_exec(). This saves a malloc/free per call. The default value of
+POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
+when configuring.
+32. The default maximum size of a compiled pattern is 64K. There have been a
+few cases of people hitting this limit. The code now uses macros to handle the
+storing of links as offsets within the compiled pattern. It defaults to 2-byte
+links, but this can be changed to 3 or 4 bytes by --with-link-size when
+configuring. Tests 2 and 5 work only with 2-byte links because they output
+debugging information about compiled patterns.
+33. Internal code re-arrangements:
+(a) Moved the debugging function for printing out a compiled regex into
+its own source file (printint.c) and used #include to pull it into
+pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
+separate copies.
+(b) Defined the list of op-code names for debugging as a macro in
+internal.h so that it is next to the definition of the opcodes.
+(c) Defined a table of op-code lengths for simpler skipping along compiled
+code. This is again a macro in internal.h so that it is next to the
+definition of the opcodes.
+34. Added support for recursive calls to individual subpatterns, along the
+lines of Robin Houston's patch (but implemented somewhat differently).
+35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
+allow it to read and process whole directories in Win32. This code was
+contributed by Lionel Fourquaux; it has not been tested by me.
+36. Added support for named subpatterns. The Python syntax (?P<name>...) is
+used to name a group. Names consist of alphanumerics and underscores, and must
+be unique. Back references use the syntax (?P=name) and recursive calls use
+(?P>name) which is a PCRE extension to the Python extension. Groups still have
+numbers. The function pcre_fullinfo() can be used after compilation to extract
+a name/number map. There are three relevant calls:
+PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
+PCRE_INFO_NAMECOUNT            yields the number of entries
+PCRE_INFO_NAMETABLE            yields a pointer to the map.
+The map is a vector of fixed-size entries. The size of each entry depends on
+the length of the longest name used. The first two bytes of each entry are the
+group number, most significant byte first. There follows the corresponding
+name, zero terminated. The names are in alphabetical order.
+37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
+case instead of 255. Making it the same both with and without UTF-8 support
+means that the same test output works with both.
+38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
+calling malloc() with a zero argument.
+39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
+optimization. I've improved things by keeping a bitmap of backreferences with
+numbers 1-31 so that if .* occurs inside capturing brackets that are not in
+fact referenced, the optimization can be applied. It is unlikely that a
+relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
+the match to follow \n) will appear inside brackets with a number greater than
+31, but if it does, any back reference > 31 suppresses the optimization.
+40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
+of disabling numbered capturing parentheses. Any opening parenthesis that is
+not followed by ? behaves as if it were followed by ?: but named parentheses
+can still be used for capturing (and they will acquire numbers in the usual
+way).
+41. Redesigned the return codes from the match() function into yes/no/error so
+that errors can be passed back from deep inside the nested calls. A malloc
+failure while inside a recursive subpattern call now causes the
+PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
+42. It is now possible to set a limit on the number of times the match()
+function is called in a call to pcre_exec(). This facility makes it possible to
+limit the amount of recursion and backtracking, though not in a directly
+obvious way, because the match() function is used in a number of different
+circumstances. The count starts from zero for each position in the subject
+string (for non-anchored patterns). The default limit is, for compatibility, a
+large number, namely 10 000 000. You can change this in two ways:
+(a) When configuring PCRE before making, you can use --with-match-limit=n
+to set a default value for the compiled library.
+(b) For each call to pcre_exec(), you can pass a pcre_extra block in which
+a different value is set. See 45 below.
+If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
+43. Added a new function pcre_config(int, void *) to enable run-time extraction
+of things that can be changed at compile time. The first argument specifies
+what is wanted and the second points to where the information is to be placed.
+The current list of available information is:
+PCRE_CONFIG_UTF8
+The output is an integer that is set to one if UTF-8 support is available;
+otherwise it is set to zero.
+PCRE_CONFIG_NEWLINE
+The output is an integer that it set to the value of the code that is used for
+newline. It is either LF (10) or CR (13).
+PCRE_CONFIG_LINK_SIZE
+The output is an integer that contains the number of bytes used for internal
+linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
+PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
+The output is an integer that contains the threshold above which the POSIX
+interface uses malloc() for output vectors. See item 31 above.
+PCRE_CONFIG_MATCH_LIMIT
+The output is an unsigned integer that contains the default limit of the number
+of match() calls in a pcre_exec() execution. See 42 above.
+44. pcretest has been upgraded by the addition of the -C option. This causes it
+to extract all the available output from the new pcre_config() function, and to
+output it. The program then exits immediately.
+45. A need has arisen to pass over additional data with calls to pcre_exec() in
+order to support additional features. One way would have been to define
+pcre_exec2() (for example) with extra arguments, but this would not have been
+extensible, and would also have required all calls to the original function to
+be mapped to the new one. Instead, I have chosen to extend the mechanism that
+is used for passing in "extra" data from pcre_study().
+The pcre_extra structure is now exposed and defined in pcre.h. It currently
+contains the following fields:
+flags         a bitmap indicating which of the following fields are set
+study_data    opaque data from pcre_study()
+match_limit   a way of specifying a limit on match() calls for a specific
+call to pcre_exec()
+callout_data  data for callouts (see 49 below)
+The flag bits are also defined in pcre.h, and are
+PCRE_EXTRA_STUDY_DATA
+PCRE_EXTRA_MATCH_LIMIT
+PCRE_EXTRA_CALLOUT_DATA
+The pcre_study() function now returns one of these new pcre_extra blocks, with
+the actual study data pointed to by the study_data field, and the
+PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
+before. That is, this change is entirely upwards-compatible and requires no
+change to existing code.
+If you want to pass in additional data to pcre_exec(), you can either place it
+in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
+block.
+46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
+data string contains the escape sequence \M, pcretest calls pcre_exec() several
+times with different match limits, until it finds the minimum value needed for
+pcre_exec() to complete. The value is then output. This can be instructive; for
+most simple matches the number is quite small, but for pathological cases it
+gets very large very quickly.
+47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
+returns the size of the data block pointed to by the study_data field in a
+pcre_extra block, that is, the value that was passed as the argument to
+pcre_malloc() when PCRE was getting memory in which to place the information
+created by pcre_study(). The fourth argument should point to a size_t variable.
+pcretest has been extended so that this information is shown after a successful
+pcre_study() call when information about the compiled regex is being displayed.
+48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
+because what follows is always an absolute path. (Later: it turns out that this
+is more than cosmetic for MinGW, because it doesn't like empty path
+components.)
+49. Some changes have been made to the callout feature (see 28 above):
+(i)  A callout function now has three choices for what it returns:
+0  =>  success, carry on matching
+> 0  =>  failure at this point, but backtrack if possible
+< 0  =>  serious error, return this value from pcre_exec()
+Negative values should normally be chosen from the set of PCRE_ERROR_xxx
+values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
+"match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
+use by callout functions. It will never be used by PCRE itself.
+(ii) The pcre_extra structure (see 45 above) has a void * field called
+callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
+pcre_callout_block structure has a field of the same name. The contents of
+the field passed in the pcre_extra structure are passed to the callout
+function in the corresponding field in the callout block. This makes it
+easier to use the same callout-containing regex from multiple threads. For
+testing, the pcretest program has a new data escape
+\C*n        pass the number n (may be negative) as callout_data
+If the callout function in pcretest receives a non-zero value as
+callout_data, it returns that value.
+50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
+there were some redundant $(CFLAGS) in commands that are now specified as
+$(LINK), which already includes $(CFLAGS).
+51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
+has been compiled with UTF-8 support *and* pcre_compile() has been compiled
+with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
+one-byte characters throughout. Note that case-insensitive matching applies
+only to characters whose values are less than 256. PCRE doesn't support the
+notion of cases for higher-valued characters.
+(i)   A character class whose characters are all within 0-255 is handled as
+a bit map, and the map is inverted for negative classes. Previously, a
+character > 255 always failed to match such a class; however it should
+match if the class was a negative one (e.g. [^ab]). This has been fixed.
+(ii)  A negated character class with a single character < 255 is coded as
+"not this character" (OP_NOT). This wasn't working properly when the test
+character was multibyte, either singly or repeated.
+(iii) Repeats of multibyte characters are now handled correctly in UTF-8
+mode, for example: \x{100}{2,3}.
+(iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
+singly or repeated) now correctly test multibyte characters. However,
+PCRE doesn't recognize any characters with values greater than 255 as
+digits, spaces, or word characters. Such characters always match \D, \S,
+and \W, and never match \d, \s, or \w.
+(v)   Classes may now contain characters and character ranges with values
+greater than 255. For example: [ab\x{100}-\x{400}].
+(vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
+PCRE in UTF-8 mode.
+52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
+PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
+retained for backwards compatibility. (Note that LASTLITERAL is also a byte
+value.)
+53. The single man page has become too large. I have therefore split it up into
+a number of separate man pages. These also give rise to individual HTML pages;
+these are now put in a separate directory, and there is an index.html page that
+lists them all. Some hyperlinking between the pages has been installed.
+54. Added convenience functions for handling named capturing parentheses.
+55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
+aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
+true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
+are faulted.
+56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
+calling configure. These values are used when compiling the dftables.c program
+which is run to generate the source of the default character tables. They
+default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
+you will need to set these values.
+57. Updated the building process for Windows DLL, as provided by Fred Cox.
+Version 3.9 02-Jan-02
+---------------------
+1. A bit of extraneous text had somehow crept into the pcregrep documentation.
+2. If --disable-static was given, the building process failed when trying to
+build pcretest and pcregrep. (For some reason it was using libtool to compile
+them, which is not right, as they aren't part of the library.)
+Version 3.8 18-Dec-01
+---------------------
+1. The experimental UTF-8 code was completely screwed up. It was packing the
+bytes in the wrong order. How dumb can you get?
+Version 3.7 29-Oct-01
+---------------------
+1. In updating pcretest to check change 1 of version 3.6, I screwed up.
+This caused pcretest, when used on the test data, to segfault. Unfortunately,
+this didn't happen under Solaris 8, where I normally test things.
+2. The Makefile had to be changed to make it work on BSD systems, where 'make'
+doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
+isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
+this fix an hour or so after the initial 3.7 release.)
+Version 3.6 23-Oct-01
+---------------------
+1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
+offsets passed as NULL with zero offset count.
+2. The config.guess and config.sub files had not been updated when I moved to
+the latest autoconf.
+Version 3.5 15-Aug-01
+---------------------
+1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
+had been forgotten.
+2. By using declared but undefined structures, we can avoid using "void"
+definitions in pcre.h while keeping the internal definitions of the structures
+private.
+3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
+user point of view, this means that both static and shared libraries are built
+by default, but this can be individually controlled. More of the work of
+handling this static/shared cases is now inside libtool instead of PCRE's make
+file.
+4. The pcretest utility is now installed along with pcregrep because it is
+useful for users (to test regexs) and by doing this, it automatically gets
+relinked by libtool. The documentation has been turned into a man page, so
+there are now .1, .txt, and .html versions in /doc.
+5. Upgrades to pcregrep:
+(i)   Added long-form option names like gnu grep.
+(ii)  Added --help to list all options with an explanatory phrase.
+(iii) Added -r, --recursive to recurse into sub-directories.
+(iv)  Added -f, --file to read patterns from a file.
+6. pcre_exec() was referring to its "code" argument before testing that
+argument for NULL (and giving an error if it was NULL).
+7. Upgraded Makefile.in to allow for compiling in a different directory from
+the source directory.
+8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
+options bits, the pointer it was passed was to an int instead of to an unsigned
+long int. This mattered only on 64-bit systems.
+9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
+generated) instead of pcre.in, which it its source. Also made the same change
+in several of the .c files.
+10. A new release of gcc defines printf() as a macro, which broke pcretest
+because it had an ifdef in the middle of a string argument for printf(). Fixed
+by using separate calls to printf().
+11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
+script, to force use of CR or LF instead of \n in the source. On non-Unix
+systems, the value can be set in config.h.
+12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
+absolute limit. Changed the text of the error message to make this clear, and
+likewise updated the man page.
+13. The limit of 99 on the number of capturing subpatterns has been removed.
+The new limit is 65535, which I hope will not be a "real" limit.
+Version 3.4 22-Aug-00
+---------------------
+1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
+2. Diagnose condition (?(0) as an error instead of crashing on matching.
+Version 3.3 01-Aug-00
+---------------------
+1. If an octal character was given, but the value was greater than \377, it
+was not getting masked to the least significant bits, as documented. This could
+lead to crashes in some systems.
+2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
+the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
+3. Added the functions pcre_free_substring() and pcre_free_substring_list().
+These just pass their arguments on to (pcre_free)(), but they are provided
+because some uses of PCRE bind it to non-C systems that can call its functions,
+but cannot call free() or pcre_free() directly.
+4. Add "make test" as a synonym for "make check". Corrected some comments in
+the Makefile.
+5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
+Makefile.
+6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
+command called pgrep for grepping around the active processes.
+7. Added the beginnings of support for UTF-8 character strings.
+8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
+RANLIB to ./ltconfig so that they are used by libtool. I think these are all
+the relevant ones. (AR is not passed because ./ltconfig does its own figuring
+out for the ar command.)
+Version 3.2 12-May-00
+---------------------
+This is purely a bug fixing release.
+1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
+of ZA. This was just one example of several cases that could provoke this bug,
+which was introduced by change 9 of version 2.00. The code for breaking
+infinite loops after an iteration that matches an empty string was't working
+correctly.
+2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
+when matched against abbab (for example). After matching an empty string, it
+wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
+caused it to match further down the string than it should.
+3. The code contained an inclusion of sys/types.h. It isn't clear why this
+was there because it doesn't seem to be needed, and it causes trouble on some
+systems, as it is not a Standard C header. It has been removed.
+4. Made 4 silly changes to the source to avoid stupid compiler warnings that
+were reported on the Macintosh. The changes were from
+while ((c = *(++ptr)) != 0 && c != '\n');
+to
+while ((c = *(++ptr)) != 0 && c != '\n') ;
+Totally extraordinary, but if that's what it takes...
+5. PCRE is being used in one environment where neither memmove() nor bcopy() is
+available. Added HAVE_BCOPY and an autoconf test for it; if neither
+HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
+assumes the way PCRE uses memmove() (always moving upwards).
+6. PCRE is being used in one environment where strchr() is not available. There
+was only one use in pcre.c, and writing it out to avoid strchr() probably gives
+faster code anyway.
+Version 3.1 09-Feb-00
+---------------------
+The only change in this release is the fixing of some bugs in Makefile.in for
+the "install" target:
+(1) It was failing to install pcreposix.h.
+(2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
+Version 3.0 01-Feb-00
+---------------------
+1. Add support for the /+ modifier to perltest (to output $` like it does in
+pcretest).
+2. Add support for the /g modifier to perltest.
+3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
+matches null strings.
+4. Fix perltest so that it doesn't do unwanted things when fed an empty
+pattern. Perl treats empty patterns specially - it reuses the most recent
+pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
+effect.
+5. The POSIX interface was broken in that it was just handing over the POSIX
+captured string vector to pcre_exec(), but (since release 2.00) PCRE has
+required a bigger vector, with some working space on the end. This means that
+the POSIX wrapper now has to get and free some memory, and copy the results.
+6. Added some simple autoconf support, placing the test data and the
+documentation in separate directories, re-organizing some of the
+information files, and making it build pcre-config (a GNU standard). Also added
+libtool support for building PCRE as a shared library, which is now the
+default.
+7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
+09 are not valid octal constants. Single digits will be used for minor values
+less than 10.
+8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
+existing programs that set these in the POSIX interface can use PCRE without
+modification.
+9. Added a new function, pcre_fullinfo() with an extensible interface. It can
+return all that pcre_info() returns, plus additional data. The pcre_info()
+function is retained for compatibility, but is considered to be obsolete.
+10. Added experimental recursion feature (?R) to handle one common case that
+Perl 5.6 will be able to do with (?p{...}).
+11. Added support for POSIX character classes like [:alpha:], which Perl is
+adopting.
+Version 2.08 31-Aug-99
+----------------------
+1. When startoffset was not zero and the pattern began with ".*", PCRE was not
+trying to match at the startoffset position, but instead was moving forward to
+the next newline as if a previous match had failed.
+2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
+and could get into a loop if a null string was matched other than at the start
+of the subject.
+3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
+be distinguished at compile time, and for completeness also added PCRE_DATE.
+5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
+in GnuWin32 environments.
+Version 2.07 29-Jul-99
+----------------------
+1. The documentation is now supplied in plain text form and HTML as well as in
+the form of man page sources.
+2. C++ compilers don't like assigning (void *) values to other pointer types.
+In particular this affects malloc(). Although there is no problem in Standard
+C, I've put in casts to keep C++ compilers happy.
+3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
+should be (const char *).
+4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
+be useful for non-Unix systems who don't want to bother with the POSIX stuff.
+However, I haven't made this a standard facility. The documentation doesn't
+mention it, and the Makefile doesn't support it.
+5. The Makefile now contains an "install" target, with editable destinations at
+the top of the file. The pcretest program is not installed.
+6. pgrep -V now gives the PCRE version number and date.
+7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
+causing the entire string to be ignored, instead of just the last character.
+8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
+non-matching string, it can take a very, very long time, even for strings of
+quite modest length, because of the nested recursion. PCRE now does better in
+some of these cases. It does this by remembering the last required literal
+character in the pattern, and pre-searching the subject to ensure it is present
+before running the real match. In other words, it applies a heuristic to detect
+some types of certain failure quickly, and in the above example, if presented
+with a string that has no trailing " it gives "no match" very quickly.
+9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
+other alternatives are tried instead.
+Version 2.06 09-Jun-99
+----------------------
+1. Change pcretest's output for amount of store used to show just the code
+space, because the remainder (the data block) varies in size between 32-bit and
+64-bit systems.
+2. Added an extra argument to pcre_exec() to supply an offset in the subject to
+start matching at. This allows lookbehinds to work when searching for multiple
+occurrences in a string.
+3. Added additional options to pcretest for testing multiple occurrences:
+/+   outputs the rest of the string that follows a match
+/g   loops for multiple occurrences, using the new startoffset argument
+/G   loops for multiple occurrences by passing an incremented pointer
+4. PCRE wasn't doing the "first character" optimization for patterns starting
+with \b or \B, though it was doing it for other lookbehind assertions. That is,
+it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
+the letter 'x'. On long subject strings, this gives a significant speed-up.
+Version 2.05 21-Apr-99
+----------------------
+1. Changed the type of magic_number from int to long int so that it works
+properly on 16-bit systems.
+2. Fixed a bug which caused patterns starting with .* not to work correctly
+when the subject string contained newline characters. PCRE was assuming
+anchoring for such patterns in all cases, which is not correct because .* will
+not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
+DOTALL is set at top level; otherwise it knows that patterns starting with .*
+must be retried after every newline in the subject.
+Version 2.04 18-Feb-99
+----------------------
+1. For parenthesized subpatterns with repeats whose minimum was zero, the
+computation of the store needed to hold the pattern was incorrect (too large).
+If such patterns were nested a few deep, this could multiply and become a real
+problem.
+2. Added /M option to pcretest to show the memory requirement of a specific
+pattern. Made -m a synonym of -s (which does this globally) for compatibility.
+3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
+compiled in such a way that the backtracking after subsequent failure was
+pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
+((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
+Version 2.03 02-Feb-99
+----------------------
+1. Fixed typo and small mistake in man page.
+2. Added 4th condition (GPL supersedes if conflict) and created separate
+LICENCE file containing the conditions.
+3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
+Perl, that is the internal \ allows the delimiter to be included in the
+pattern. Locked out the use of \ as a delimiter. If \ immediately follows
+the final delimiter, add \ to the end of the pattern (to test the error).
+4. Added the convenience functions for extracting substrings after a successful
+match. Updated pcretest to make it able to test these functions.
+Version 2.02 14-Jan-99
+----------------------
+1. Initialized the working variables associated with each extraction so that
+their saving and restoring doesn't refer to uninitialized store.
+2. Put dummy code into study.c in order to trick the optimizer of the IBM C
+compiler for OS/2 into generating correct code. Apparently IBM isn't going to
+fix the problem.
+3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
+calls, and wasn't printing the correct value for compiling calls. Increased the
+default value of LOOPREPEAT, and the number of significant figures in the
+times.
+4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
+5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
+a building problem on Windows NT with a FAT file system.
+Version 2.01 21-Oct-98
+----------------------
+1. Changed the API for pcre_compile() to allow for the provision of a pointer
+to character tables built by pcre_maketables() in the current locale. If NULL
+is passed, the default tables are used.
+Version 2.00 24-Sep-98
+----------------------
+1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
+it any more.
+2. Allow quantification of (?>) groups, and make it work correctly.
+3. The first character computation wasn't working for (?>) groups.
+4. Correct the implementation of \Z (it is permitted to match on the \n at the
+end of the subject) and add 5.005's \z, which really does match only at the
+very end of the subject.
+5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
+6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
+DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
+localized options. All options to pcre_study() were also removed.
+7. Add other new features from 5.005:
+$(?<=           positive lookbehind
+$(?<!           negative lookbehind
+(?imsx-imsx)    added the unsetting capability
+such a setting is global if at outer level; local otherwise
+(?imsx-imsx:)   non-capturing groups with option setting
+(?(cond)re|re)  conditional pattern matching
+A backreference to itself in a repeated group matches the previous
+captured string.
+8. General tidying up of studying (both automatic and via "study")
+consequential on the addition of new assertions.
+9. As in 5.005, unlimited repeated groups that could match an empty substring
+are no longer faulted at compile time. Instead, the loop is forcibly broken at
+runtime if any iteration does actually match an empty substring.
+10. Include the RunTest script in the distribution.
+11. Added tests from the Perl 5.005_02 distribution. This showed up a few
+discrepancies, some of which were old and were also with respect to 5.004. They
+have now been fixed.
+Version 1.09 28-Apr-98
+----------------------
+1. A negated single character class followed by a quantifier with a minimum
+value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
+program crashes, or just wrong answers. This did not apply to negated classes
+containing more than one character, or to minima other than one.
+Version 1.08 27-Mar-98
+----------------------
+1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
+2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
+latter must appear before anything that relies on it in the pattern.
+Version 1.07 16-Feb-98
+----------------------
+1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
+repeat of a potentially empty string).
+Version 1.06 23-Jan-98
+----------------------
+1. Added Markus Oberhumer's little patches for C++.
+2. Literal strings longer than 255 characters were broken.
+Version 1.05 23-Dec-97
+----------------------
+1. Negated character classes containing more than one character were failing if
+PCRE_CASELESS was set at run time.
+Version 1.04 19-Dec-97
+----------------------
+1. Corrected the man page, where some "const" qualifiers had been omitted.
+2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
+input syntax.
+3. Fixed memory leak which occurred when a regex with back references was
+matched with an offsets vector that wasn't big enough. The temporary memory
+that is used in this case wasn't being freed if the match failed.
+4. Tidied pcretest to ensure it frees memory that it gets.
+5. Temporary memory was being obtained in the case where the passed offsets
+vector was exactly big enough.
+6. Corrected definition of offsetof() from change 5 below.
+7. I had screwed up change 6 below and broken the rules for the use of
+setjmp(). Now fixed.
+Version 1.03 18-Dec-97
+----------------------
+1. A erroneous regex with a missing opening parenthesis was correctly
+diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
+on some systems.
+2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
+it was reported that one broken compiler failed on the former because "code" is
+also an independent variable.
+3. The erroneous regex a[]b caused an array overrun reference.
+4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
+fail on data ending with that character. (It was going on too far, and checking
+the next character, typically a binary zero.) This was specific to the
+optimized code for single-character negative classes.
+5. Added a contributed patch from the TIN world which does the following:
++ Add an undef for memmove, in case the the system defines a macro for it.
++ Add a definition of offsetof(), in case there isn't one. (I don't know
+the reason behind this - offsetof() is part of the ANSI standard - but
+it does no harm).
++ Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
+most of the places where whitespace preceded '#'. I have given up and
+allowed the remaining 2 cases to be at the margin.
++ Rename some variables in pcre to eliminate shadowing. This seems very
+pedantic, but does no harm, of course.
+6. Moved the call to setjmp() into its own function, to get rid of warnings
+from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
+7. Constructs such as \d{8,} were compiling into the equivalent of
+\d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
+outcome, but in this particular case used more store than had been allocated,
+which caused the bug to be discovered because it threw up an internal error.
+8. The debugging code in both pcre and pcretest for outputting the compiled
+form of a regex was going wrong in the case of back references followed by
+curly-bracketed repeats.
+Version 1.02 12-Dec-97
+----------------------
+1. Typos in pcre.3 and comments in the source fixed.
+2. Applied a contributed patch to get rid of places where it used to remove
+'const' from variables, and fixed some signed/unsigned and uninitialized
+variable warnings.
+3. Added the "runtest" target to Makefile.
+4. Set default compiler flag to -O2 rather than just -O.
+Version 1.01 19-Nov-97
+----------------------
+1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
+like /([ab]*)*/, that is, for classes with more than one character in them.
+2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
+as /((?>a*))*/ (a PCRE_EXTRA facility).
+Version 1.00 18-Nov-97
+----------------------
+1. Added compile-time macros to support systems such as SunOS4 which don't have
+memmove() or strerror() but have other things that can be used instead.
+2. Arranged that "make clean" removes the executables.
+Version 0.99 27-Oct-97
+----------------------
+1. Fixed bug in code for optimizing classes with only one character. It was
+initializing a 32-byte map regardless, which could cause it to run off the end
+of the memory it had got.
+2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
+Version 0.98 22-Oct-97
+----------------------
+1. Fixed bug in code for handling temporary memory usage when there are more
+back references than supplied space in the ovector. This could cause segfaults.
+Version 0.97 21-Oct-97
+----------------------
+1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
+2. Optimized negated single characters not to use a bit map.
+3. Brought error texts together as macro definitions; clarified some of them;
+fixed one that was wrong - it said "range out of order" when it meant "invalid
+escape sequence".
+4. Changed some char * arguments to const char *.
+5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
+6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
+pcretest.
+Version 0.96 16-Oct-97
+----------------------
+1. Added a simple "pgrep" utility to the distribution.
+2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
+unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
+where "ddd" means "one or more decimal digits".
+3. Fixed serious bug. If a pattern had a back reference, but the call to
+pcre_exec() didn't supply a large enough ovector to record the related
+identifying subpattern, the match always failed. PCRE now remembers the number
+of the largest back reference, and gets some temporary memory in which to save
+the offsets during matching if necessary, in order to ensure that
+backreferences always work.
+4. Increased the compatibility with Perl in a number of ways:
+(a) . no longer matches \n by default; an option PCRE_DOTALL is provided
+to request this handling. The option can be set at compile or exec time.
+(b) $ matches before a terminating newline by default; an option
+PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
+mode). The option can be set at compile or exec time.
+(c) The handling of \ followed by a digit other than 0 is now supposed to be
+the same as Perl's. If the decimal number it represents is less than 10
+or there aren't that many previous left capturing parentheses, an octal
+escape is read. Inside a character class, it's always an octal escape,
+even if it is a single digit.
+(d) An escaped but undefined alphabetic character is taken as a literal,
+unless PCRE_EXTRA is set. Currently this just reserves the remaining
+escapes.
+(e) {0} is now permitted. (The previous item is removed from the compiled
+pattern).
+5. Changed all the names of code files so that the basic parts are no longer
+than 10 characters, and abolished the teeny "globals.c" file.
+6. Changed the handling of character classes; they are now done with a 32-byte
+bit map always.
+7. Added the -d and /D options to pcretest to make it possible to look at the
+internals of compilation without having to recompile pcre.
+Version 0.95 23-Sep-97
+----------------------
+1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
+\x20 at the start of a run of normal characters. These were being treated as
+real characters, instead of the source characters being re-checked.
+Version 0.94 18-Sep-97
+----------------------
+1. The functions are now thread-safe, with the caveat that the global variables
+containing pointers to malloc() and free() or alternative functions are the
+same for all threads.
+2. Get pcre_study() to generate a bitmap of initial characters for non-
+anchored patterns when this is possible, and use it if passed to pcre_exec().
+Version 0.93 15-Sep-97
+----------------------
+1. /(b)|(:+)/ was computing an incorrect first character.
+2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
+but not actually doing anything yet.
+3. Treat "-" characters in classes that cannot be part of ranges as literals,
+as Perl does (e.g. [-az] or [az-]).
+4. Set the anchored flag if a branch starts with .* or .*? because that tests
+all possible positions.
+5. Split up into different modules to avoid including unneeded functions in a
+compiled binary. However, compile and exec are still in one module. The "study"
+function is split off.
+6. The character tables are now in a separate module whose source is generated
+by an auxiliary program - but can then be edited by hand if required. There are
+now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
+toupper() in the code.
+7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
+make them global. Abolish the function for setting them, as the caller can now
+set them directly.
+Version 0.92 11-Sep-97
+----------------------
+1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
+(e.g. /a{1,3}/) was broken (I mis-optimized it).
+2. Caseless matching was not working in character classes if the characters in
+the pattern were in upper case.
+3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
+4. Make PCRE_ANCHORED public and accept as a compile option.
+5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
+PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
+pass them.
+6. Give an error if bad option bits passed at compile or run time.
+7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
+pcretest to cause it to pass that flag.
+8. Add pcre_info(), to get the number of identifying subpatterns, the stored
+options, and the first character, if set.
+9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
+Version 0.91 10-Sep-97
+----------------------
+1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
+match the empty string as in /(a*)*/. It was looping and ultimately crashing.
+2. PCRE was looping on encountering an indefinitely repeated back reference to
+a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
+Perl does - treats the match as successful.
+****