ChangeLog for PCRE

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Version 7.8 05-Sep-08

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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

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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

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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