fontservices/textshaperplugin/IcuSource/common/util.h
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     1 /*
       
     2 **********************************************************************
       
     3 *   Copyright (c) 2001-2005, International Business Machines
       
     4 *   Corporation and others.  All Rights Reserved.
       
     5 **********************************************************************
       
     6 *   Date        Name        Description
       
     7 *   11/19/2001  aliu        Creation.
       
     8 **********************************************************************
       
     9 */
       
    10 #ifndef ICU_UTIL_H
       
    11 #define ICU_UTIL_H
       
    12 
       
    13 #include "unicode/utypes.h"
       
    14 #include "unicode/uobject.h"
       
    15 #include "unicode/unistr.h"
       
    16 
       
    17 //--------------------------------------------------------------------
       
    18 // class ICU_Utility
       
    19 // i18n utility functions, scoped into the class ICU_Utility.
       
    20 //--------------------------------------------------------------------
       
    21 
       
    22 U_NAMESPACE_BEGIN
       
    23 
       
    24 class UnicodeMatcher;
       
    25 
       
    26 class U_COMMON_API ICU_Utility /* not : public UObject because all methods are static */ {
       
    27  public:
       
    28 
       
    29     /**
       
    30      * Append a number to the given UnicodeString in the given radix.
       
    31      * Standard digits '0'-'9' are used and letters 'A'-'Z' for
       
    32      * radices 11 through 36.
       
    33      * @param result the digits of the number are appended here
       
    34      * @param n the number to be converted to digits; may be negative.
       
    35      * If negative, a '-' is prepended to the digits.
       
    36      * @param radix a radix from 2 to 36 inclusive.
       
    37      * @param minDigits the minimum number of digits, not including
       
    38      * any '-', to produce.  Values less than 2 have no effect.  One
       
    39      * digit is always emitted regardless of this parameter.
       
    40      * @return a reference to result
       
    41      */
       
    42     static UnicodeString& appendNumber(UnicodeString& result, int32_t n,
       
    43                                        int32_t radix = 10,
       
    44                                        int32_t minDigits = 1);
       
    45 
       
    46     /**
       
    47      * Return true if the character is NOT printable ASCII.
       
    48      *
       
    49      * This method should really be in UnicodeString (or similar).  For
       
    50      * now, we implement it here and share it with friend classes.
       
    51      */
       
    52     static UBool isUnprintable(UChar32 c);
       
    53 
       
    54     /**
       
    55      * Escape unprintable characters using \uxxxx notation for U+0000 to
       
    56      * U+FFFF and \Uxxxxxxxx for U+10000 and above.  If the character is
       
    57      * printable ASCII, then do nothing and return FALSE.  Otherwise,
       
    58      * append the escaped notation and return TRUE.
       
    59      */
       
    60     static UBool escapeUnprintable(UnicodeString& result, UChar32 c);
       
    61 
       
    62     /**
       
    63      * Returns the index of a character, ignoring quoted text.
       
    64      * For example, in the string "abc'hide'h", the 'h' in "hide" will not be
       
    65      * found by a search for 'h'.
       
    66      * @param text text to be searched
       
    67      * @param start the beginning index, inclusive; <code>0 <= start
       
    68      * <= limit</code>.
       
    69      * @param limit the ending index, exclusive; <code>start <= limit
       
    70      * <= text.length()</code>.
       
    71      * @param c character to search for
       
    72      * @return Offset of the first instance of c, or -1 if not found.
       
    73      */
       
    74 //?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
       
    75 //    static int32_t quotedIndexOf(const UnicodeString& text,
       
    76 //                                 int32_t start, int32_t limit,
       
    77 //                                 UChar c);
       
    78 
       
    79     /**
       
    80      * Skip over a sequence of zero or more white space characters at pos.
       
    81      * @param advance if true, advance pos to the first non-white-space
       
    82      * character at or after pos, or str.length(), if there is none.
       
    83      * Otherwise leave pos unchanged.
       
    84      * @return the index of the first non-white-space character at or
       
    85      * after pos, or str.length(), if there is none.
       
    86      */
       
    87     static int32_t skipWhitespace(const UnicodeString& str, int32_t& pos,
       
    88                                   UBool advance = FALSE);
       
    89 
       
    90     /**
       
    91      * Skip over whitespace in a Replaceable.  Whitespace is defined by
       
    92      * uprv_isRuleWhiteSpace().  Skipping may be done in the forward or
       
    93      * reverse direction.  In either case, the leftmost index will be
       
    94      * inclusive, and the rightmost index will be exclusive.  That is,
       
    95      * given a range defined as [start, limit), the call
       
    96      * skipWhitespace(text, start, limit) will advance start past leading
       
    97      * whitespace, whereas the call skipWhitespace(text, limit, start),
       
    98      * will back up limit past trailing whitespace.
       
    99      * @param text the text to be analyzed
       
   100      * @param pos either the start or limit of a range of 'text', to skip
       
   101      * leading or trailing whitespace, respectively
       
   102      * @param stop either the limit or start of a range of 'text', to skip
       
   103      * leading or trailing whitespace, respectively
       
   104      * @return the new start or limit, depending on what was passed in to
       
   105      * 'pos'
       
   106      */
       
   107 //?FOR FUTURE USE.  DISABLE FOR NOW for coverage reasons.
       
   108 //?    static int32_t skipWhitespace(const Replaceable& text,
       
   109 //?                                  int32_t pos, int32_t stop);
       
   110 
       
   111     /**
       
   112      * Parse a single non-whitespace character 'ch', optionally
       
   113      * preceded by whitespace.
       
   114      * @param id the string to be parsed
       
   115      * @param pos INPUT-OUTPUT parameter.  On input, pos[0] is the
       
   116      * offset of the first character to be parsed.  On output, pos[0]
       
   117      * is the index after the last parsed character.  If the parse
       
   118      * fails, pos[0] will be unchanged.
       
   119      * @param ch the non-whitespace character to be parsed.
       
   120      * @return true if 'ch' is seen preceded by zero or more
       
   121      * whitespace characters.
       
   122      */
       
   123     static UBool parseChar(const UnicodeString& id, int32_t& pos, UChar ch);
       
   124 
       
   125     /**
       
   126      * Parse a pattern string starting at offset pos.  Keywords are
       
   127      * matched case-insensitively.  Spaces may be skipped and may be
       
   128      * optional or required.  Integer values may be parsed, and if
       
   129      * they are, they will be returned in the given array.  If
       
   130      * successful, the offset of the next non-space character is
       
   131      * returned.  On failure, -1 is returned.
       
   132      * @param pattern must only contain lowercase characters, which
       
   133      * will match their uppercase equivalents as well.  A space
       
   134      * character matches one or more required spaces.  A '~' character
       
   135      * matches zero or more optional spaces.  A '#' character matches
       
   136      * an integer and stores it in parsedInts, which the caller must
       
   137      * ensure has enough capacity.
       
   138      * @param parsedInts array to receive parsed integers.  Caller
       
   139      * must ensure that parsedInts.length is >= the number of '#'
       
   140      * signs in 'pattern'.
       
   141      * @return the position after the last character parsed, or -1 if
       
   142      * the parse failed
       
   143      */
       
   144     static int32_t parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
       
   145                                 const UnicodeString& pattern, int32_t* parsedInts);
       
   146         
       
   147     /**
       
   148      * Parse a pattern string within the given Replaceable and a parsing
       
   149      * pattern.  Characters are matched literally and case-sensitively
       
   150      * except for the following special characters:
       
   151      *
       
   152      * ~  zero or more uprv_isRuleWhiteSpace chars
       
   153      *
       
   154      * If end of pattern is reached with all matches along the way,
       
   155      * pos is advanced to the first unparsed index and returned.
       
   156      * Otherwise -1 is returned.
       
   157      * @param pat pattern that controls parsing
       
   158      * @param text text to be parsed, starting at index
       
   159      * @param index offset to first character to parse
       
   160      * @param limit offset after last character to parse
       
   161      * @return index after last parsed character, or -1 on parse failure.
       
   162      */
       
   163     static int32_t parsePattern(const UnicodeString& pat,
       
   164                                 const Replaceable& text,
       
   165                                 int32_t index,
       
   166                                 int32_t limit);
       
   167 
       
   168     /**
       
   169      * Parse an integer at pos, either of the form \d+ or of the form
       
   170      * 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
       
   171      * or octal format.
       
   172      * @param pos INPUT-OUTPUT parameter.  On input, the first
       
   173      * character to parse.  On output, the character after the last
       
   174      * parsed character.
       
   175      */
       
   176     static int32_t parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit);
       
   177 
       
   178     /**
       
   179      * Parse a Unicode identifier from the given string at the given
       
   180      * position.  Return the identifier, or an empty string if there
       
   181      * is no identifier.
       
   182      * @param str the string to parse
       
   183      * @param pos INPUT-OUPUT parameter.  On INPUT, pos is the
       
   184      * first character to examine.  It must be less than str.length(),
       
   185      * and it must not point to a whitespace character.  That is, must
       
   186      * have pos < str.length() and
       
   187      * !UCharacter::isWhitespace(str.char32At(pos)).  On
       
   188      * OUTPUT, the position after the last parsed character.
       
   189      * @return the Unicode identifier, or an empty string if there is
       
   190      * no valid identifier at pos.
       
   191      */
       
   192     static UnicodeString parseUnicodeIdentifier(const UnicodeString& str, int32_t& pos);
       
   193 
       
   194     /**
       
   195      * Parse an unsigned 31-bit integer at the given offset.  Use
       
   196      * UCharacter.digit() to parse individual characters into digits.
       
   197      * @param text the text to be parsed
       
   198      * @param pos INPUT-OUTPUT parameter.  On entry, pos is the
       
   199      * offset within text at which to start parsing; it should point
       
   200      * to a valid digit.  On exit, pos is the offset after the last
       
   201      * parsed character.  If the parse failed, it will be unchanged on
       
   202      * exit.  Must be >= 0 on entry.
       
   203      * @param radix the radix in which to parse; must be >= 2 and <=
       
   204      * 36.
       
   205      * @return a non-negative parsed number, or -1 upon parse failure.
       
   206      * Parse fails if there are no digits, that is, if pos does not
       
   207      * point to a valid digit on entry, or if the number to be parsed
       
   208      * does not fit into a 31-bit unsigned integer.
       
   209      */
       
   210     static int32_t parseNumber(const UnicodeString& text,
       
   211                                int32_t& pos, int8_t radix);
       
   212 
       
   213     static void appendToRule(UnicodeString& rule,
       
   214                              UChar32 c,
       
   215                              UBool isLiteral,
       
   216                              UBool escapeUnprintable,
       
   217                              UnicodeString& quoteBuf);
       
   218     
       
   219     static void appendToRule(UnicodeString& rule,
       
   220                              const UnicodeString& text,
       
   221                              UBool isLiteral,
       
   222                              UBool escapeUnprintable,
       
   223                              UnicodeString& quoteBuf);
       
   224 
       
   225     static void appendToRule(UnicodeString& rule,
       
   226                              const UnicodeMatcher* matcher,
       
   227                              UBool escapeUnprintable,
       
   228                              UnicodeString& quoteBuf);
       
   229 
       
   230 private:
       
   231     // do not instantiate
       
   232     ICU_Utility();
       
   233 };
       
   234 
       
   235 U_NAMESPACE_END
       
   236 
       
   237 /**
       
   238  * Is this character a "white space" in the sense of ICU rule parsers?
       
   239  * Equivalent to test for Pattern_White_Space Unicode property.
       
   240  * Stable set of characters, won't change.
       
   241  * See UAX #31 Identifier and Pattern Syntax: http://www.unicode.org/reports/tr31/
       
   242  * @internal
       
   243  */
       
   244 U_CAPI UBool U_EXPORT2
       
   245 uprv_isRuleWhiteSpace(UChar32 c);
       
   246 
       
   247 #endif
       
   248 //eof