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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.8 25-Aug-08
5    ---------------------
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
35    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
36        test 2 if it fails.
38    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
39        and a #define of that name to empty if it is not externally set. This is to
40        allow users of MSVC to set it if necessary.
42    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
43        the convenience functions in the pcre_get.c source file.
45    11. An option change at the start of a pattern that had top-level alternatives
46        could cause overwriting and/or a crash. This command provoked a crash in
47        some environments:
49          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
51        This potential security problem was recorded as CVE-2008-2371.
53    12. For a pattern where the match had to start at the beginning or immediately
54        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
55        pcre_dfa_exec() could read past the end of the passed subject if there was
56        no match. To help with detecting such bugs (e.g. with valgrind), I modified
57        pcretest so that it places the subject at the end of its malloc-ed buffer.
59    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
60        exec() might read past the end of the data buffer in UTF-8 mode.
62    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
63        the data contained the byte 0x85 as part of a UTF-8 character within its
64        first line. This applied both to normal and DFA matching.
66    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
67        /^[^d]*?$/8 failed to match "abc".
69    16. Added a missing copyright notice to pcrecpp_internal.h.
71    17. Make it more clear in the documentation that values returned from
72        pcre_exec() in ovector are byte offsets, not character counts.
74    18. Tidied a few places to stop certain compilers from issuing warnings.
76    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
77        supplied by Stefan Weber. I made a further small update for 7.8 because
78        there is a change of source arrangements: the pcre_searchfuncs.c module is
79        replaced by pcre_ucd.c.
82    Version 7.7 07-May-08
83    ---------------------
85    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
86        a string to a long long, pretend we don't even have a long long." This is
87        done by checking for the strtoq, strtoll, and _strtoi64 functions.
89    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
90        pre-7.6 versions, which defined a global no_arg variable instead of putting
91        it in the RE class. (See also #8 below.)
93    3.  Remove a line of dead code, identified by coverity and reported by Nuno
94        Lopes.
96    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
98        (1) The include/exclude patterns were being applied to the whole pathnames
99            of files, instead of just to the final components.
101        (2) If there was more than one level of directory, the subdirectories were
102            skipped unless they satisfied the include/exclude conditions. This is
103            inconsistent with GNU grep (and could even be seen as contrary to the
104            pcregrep specification - which I improved to make it absolutely clear).
105            The action now is always to scan all levels of directory, and just
106            apply the include/exclude patterns to regular files.
108    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
109        --exclude_dir in the tests to avoid scanning .svn directories.
111    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
112        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
113        doesn't support NULs in patterns.
115    7.  Added some missing "const"s to declarations of static tables in
116        pcre_compile.c and pcre_dfa_exec.c.
118    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
119        caused by fix #2  above. (Subsequently also a second patch to fix the
120        first patch. And a third patch - this was a messy problem.)
122    9.  Applied Craig's patch to remove the use of push_back().
124    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
125        matching function regexec().
127    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
128        which, however, unlike Perl's \g{...}, are subroutine calls, not back
129        references. PCRE supports relative numbers with this syntax (I don't think
130        Oniguruma does).
132    12. Previously, a group with a zero repeat such as (...){0} was completely
133        omitted from the compiled regex. However, this means that if the group
134        was called as a subroutine from elsewhere in the pattern, things went wrong
135        (an internal error was given). Such groups are now left in the compiled
136        pattern, with a new opcode that causes them to be skipped at execution
137        time.
139    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
140        to the way PCRE behaves:
142        (a) A lone ] character is dis-allowed (Perl treats it as data).
144        (b) A back reference to an unmatched subpattern matches an empty string
145            (Perl fails the current match path).
147        (c) A data ] in a character class must be notated as \] because if the
148            first data character in a class is ], it defines an empty class. (In
149            Perl it is not possible to have an empty class.) The empty class []
150            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
151            The negative empty class [^] matches any one character, independently
152            of the DOTALL setting.
154    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
155        non-existent subpattern following a character class starting with ']' and
156        containing () gave an internal compiling error instead of "reference to
157        non-existent subpattern". Fortunately, when the pattern did exist, the
158        compiled code was correct. (When scanning forwards to check for the
159        existencd of the subpattern, it was treating the data ']' as terminating
160        the class, so got the count wrong. When actually compiling, the reference
161        was subsequently set up correctly.)
163    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
164        it was being rejected as not supported by pcre_dfa_exec(), even though
165        other assertions are supported. I have made pcre_dfa_exec() support
166        (*FAIL).
168    16. The implementation of 13c above involved the invention of a new opcode,
169        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
170        cannot be changed at match time, I realized I could make a small
171        improvement to matching performance by compiling OP_ALLANY instead of
172        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
173        on the OP_ANY path.
175    17. Compiling pcretest on Windows with readline support failed without the
176        following two fixes: (1) Make the unistd.h include conditional on
177        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
179    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
180        ncurses library to be included for pcretest when ReadLine support is
181        requested, but also to allow for it to be overridden. This patch came from
182        Daniel Bergström.
184    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
185        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
186        any errors with the current Unicode tables. Thanks to Peter Kankowski for
187        spotting this.
190    Version 7.6 28-Jan-08
191    ---------------------
193    1.  A character class containing a very large number of characters with
194        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
195        overflow.
197    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
198        HAVE_LONG_LONG is not defined.
200    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
201        bring them up to date and include new features. This patch includes:
203        - Fixed PH's badly added libz and libbz2 support.
204        - Fixed a problem with static linking.
205        - Added pcredemo. [But later removed - see 7 below.]
206        - Fixed dftables problem and added an option.
207        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
208            HAVE_LONG_LONG.
209        - Added readline support for pcretest.
210        - Added an listing of the option settings after cmake has run.
212    4.  A user submitted a patch to Makefile that makes it easy to create
213        "pcre.dll" under mingw when using Configure/Make. I added stuff to
214        Makefile.am that cause it to include this special target, without
215        affecting anything else. Note that the same mingw target plus all
216        the other distribution libraries and programs are now supported
217        when configuring with CMake (see 6 below) instead of with
218        Configure/Make.
220    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
221        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
222        exported in the Windows port". It has not yet been confirmed that the patch
223        solves the problem, but it does no harm.
225    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
226        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
227        with CMake, and also correct the comment about stack recursion.
229    7.  Remove the automatic building of pcredemo from the ./configure system and
230        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
231        of a program that users should build themselves after PCRE is installed, so
232        building it automatically is not really right. What is more, it gave
233        trouble in some build environments.
235    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
238    Version 7.5 10-Jan-08
239    ---------------------
241    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
242        values in parens when parsing an RE using the C++ wrapper."
244    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
245        Characters greater than 255 were excluded from the class instead of being
246        included.
248    3.  The same bug as (2) above applied to negated POSIX classes such as
249        [:^space:].
251    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
252        defined or documented. It seems to have been a typo for PCRE_STATIC, so
253        I have changed it.
255    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
256        first named subpattern) and a construct such as (?&a) would reference the
257        first named subpattern whose name started with "a" (in other words, the
258        length check was missing). Both these problems are fixed. "Subpattern name
259        expected" is now given for (?&) (a zero-length name), and this patch also
260        makes it give the same error for \k'' (previously it complained that that
261        was a reference to a non-existent subpattern).
263    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
264        this is right because (?- can be followed by option settings as well as by
265        digits. I have, however, made the messages clearer.
267    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
268        than the number used in the conditional) now cause a compile-time error.
269        This is actually not compatible with Perl, which accepts such patterns, but
270        treats the conditional as always being FALSE (as PCRE used to), but it
271        seems to me that giving a diagnostic is better.
273    8.  Change "alphameric" to the more common word "alphanumeric" in comments
274        and messages.
276    9.  Fix two occurrences of "backslash" in comments that should have been
277        "backspace".
279    10. Remove two redundant lines of code that can never be obeyed (their function
280        was moved elsewhere).
282    11. The program that makes PCRE's Unicode character property table had a bug
283        which caused it to generate incorrect table entries for sequences of
284        characters that have the same character type, but are in different scripts.
285        It amalgamated them into a single range, with the script of the first of
286        them. In other words, some characters were in the wrong script. There were
287        thirteen such cases, affecting characters in the following ranges:
289          U+002b0 - U+002c1
290          U+0060c - U+0060d
291          U+0061e - U+00612
292          U+0064b - U+0065e
293          U+0074d - U+0076d
294          U+01800 - U+01805
295          U+01d00 - U+01d77
296          U+01d9b - U+01dbf
297          U+0200b - U+0200f
298          U+030fc - U+030fe
299          U+03260 - U+0327f
300          U+0fb46 - U+0fbb1
301          U+10450 - U+1049d
303    12. The -o option (show only the matching part of a line) for pcregrep was not
304        compatible with GNU grep in that, if there was more than one match in a
305        line, it showed only the first of them. It now behaves in the same way as
306        GNU grep.
308    13. If the -o and -v options were combined for pcregrep, it printed a blank
309        line for every non-matching line. GNU grep prints nothing, and pcregrep now
310        does the same. The return code can be used to tell if there were any
311        non-matching lines.
313    14. Added --file-offsets and --line-offsets to pcregrep.
315    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
316        infinitely looping recursion. The bug was that positive lookaheads were not
317        being skipped when checking for a possible empty match (negative lookaheads
318        and both kinds of lookbehind were skipped).
320    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
321        inclusion of <windows.h> to before rather than after the definition of
322        INVALID_FILE_ATTRIBUTES (patch from David Byron).
324    17. Specifying a possessive quantifier with a specific limit for a Unicode
325        character property caused pcre_compile() to compile bad code, which led at
326        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
327        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
328        caused the error; without that there was no problem.
330    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
332    19. Added --enable-pcretest-libreadline.
334    20. In pcrecpp.cc, the variable 'count' was incremented twice in
335        RE::GlobalReplace(). As a result, the number of replacements returned was
336        double what it should be. I removed one of the increments, but Craig sent a
337        later patch that removed the other one (the right fix) and added unit tests
338        that check the return values (which was not done before).
340    21. Several CMake things:
342        (1) Arranged that, when cmake is used on Unix, the libraries end up with
343            the names libpcre and libpcreposix, not just pcre and pcreposix.
345        (2) The above change means that pcretest and pcregrep are now correctly
346            linked with the newly-built libraries, not previously installed ones.
350    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
351        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
352        UTF-8 newline character). The key issue is that the pattern starts .*;
353        this means that the match must be either at the beginning, or after a
354        newline. The bug was in the code for advancing after a failed match and
355        checking that the new position followed a newline. It was not taking
356        account of UTF-8 characters correctly.
358    23. PCRE was behaving differently from Perl in the way it recognized POSIX
359        character classes. PCRE was not treating the sequence [:...:] as a
360        character class unless the ... were all letters. Perl, however, seems to
361        allow any characters between [: and :], though of course it rejects as
362        unknown any "names" that contain non-letters, because all the known class
363        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
364        for example, whereas PCRE did not - it did not recognize a POSIX character
365        class. This seemed a bit dangerous, so the code has been changed to be
366        closer to Perl. The behaviour is not identical to Perl, because PCRE will
367        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
368        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
369        Perl does, and where it didn't before.
371    24. Rewrite so as to remove the single use of %n from pcregrep because in some
372        Windows environments %n is disabled by default.
375    Version 7.4 21-Sep-07
376    ---------------------
378    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
379        means that a class such as [\s] counted as "explicit reference to CR or
380        LF". That isn't really right - the whole point of the change was to try to
381        help when there was an actual mention of one of the two characters. So now
382        the change happens only if \r or \n (or a literal CR or LF) character is
383        encountered.
385    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
386        of both had grown to the point where there were only 3 bits left.
387        Fortunately, there was spare space in the data structure, and so I have
388        moved the internal flags into a new 16-bit field to free up more option
389        bits.
391    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
392        but did not set the internal JCHANGED flag - either of these is enough to
393        control the way the "get" function works - but the PCRE_INFO_JCHANGED
394        facility is supposed to tell if (?J) was ever used, so now (?J) at the
395        start sets both bits.
397    4.  Added options (at build time, compile time, exec time) to change \R from
398        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
400    5.  doc/pcresyntax.html was missing from the distribution.
402    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
403        compatibility, even though it is no longer used.
405    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
406        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
407        windows.h file is present (where different names are used). [This was
408        reversed later after testing - see 16 below.]
410    8.  Changed all #include <config.h> to #include "config.h". There were also
411        some further <pcre.h> cases that I changed to "pcre.h".
413    9.  When pcregrep was used with the --colour option, it missed the line ending
414        sequence off the lines that it output.
416    10. It was pointed out to me that arrays of string pointers cause lots of
417        relocations when a shared library is dynamically loaded. A technique of
418        using a single long string with a table of offsets can drastically reduce
419        these. I have refactored PCRE in four places to do this. The result is
420        dramatic:
422          Originally:                          290
423          After changing UCP table:            187
424          After changing error message table:   43
425          After changing table of "verbs"       36
426          After changing table of Posix names   22
428        Thanks to the folks working on Gregex for glib for this insight.
430    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
431        unicode-properties was also set.
433    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
435    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
436        checked only for CRLF.
438    14. Added casts to pcretest.c to avoid compiler warnings.
440    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
442    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
443        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
444        entirely. This removes changes made in 7 above.
446    17. The CMake files have been updated, and there is now more information about
447        building with CMake in the NON-UNIX-USE document.
450    Version 7.3 28-Aug-07
451    ---------------------
453     1. In the rejigging of the build system that eventually resulted in 7.1, the
454        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
455        brackets there is not right, since it causes compilers to look for an
456        installed pcre.h, not the version that is in the source that is being
457        compiled (which of course may be different). I have changed it back to:
459          #include "pcre.h"
461        I have a vague recollection that the change was concerned with compiling in
462        different directories, but in the new build system, that is taken care of
463        by the VPATH setting the Makefile.
465     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
466        when the subject happened to end in the byte 0x85 (e.g. if the last
467        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
468        characters but of course it shouldn't be taken as a newline when it is part
469        of another character. The bug was that, for an unlimited repeat of . in
470        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
471        characters when looking for a newline.
473     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
475     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
476        in debug output.
478     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
479        long printing in the pcrecpp unittest when running under MinGW.
481     6. ESC_K was left out of the EBCDIC table.
483     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
484        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
485        limit also applies to "virtual nesting" when a pattern is recursive, and in
486        this case 1000 isn't so big. I have been able to remove this limit at the
487        expense of backing off one optimization in certain circumstances. Normally,
488        when pcre_exec() would call its internal match() function recursively and
489        immediately return the result unconditionally, it uses a "tail recursion"
490        feature to save stack. However, when a subpattern that can match an empty
491        string has an unlimited repetition quantifier, it no longer makes this
492        optimization. That gives it a stack frame in which to save the data for
493        checking that an empty string has been matched. Previously this was taken
494        from the 1000-entry workspace that had been reserved. So now there is no
495        explicit limit, but more stack is used.
497     8. Applied Daniel's patches to solve problems with the import/export magic
498        syntax that is required for Windows, and which was going wrong for the
499        pcreposix and pcrecpp parts of the library. These were overlooked when this
500        problem was solved for the main library.
502     9. There were some crude static tests to avoid integer overflow when computing
503        the size of patterns that contain repeated groups with explicit upper
504        limits. As the maximum quantifier is 65535, the maximum group length was
505        set at 30,000 so that the product of these two numbers did not overflow a
506        32-bit integer. However, it turns out that people want to use groups that
507        are longer than 30,000 bytes (though not repeat them that many times).
508        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
509        made it possible to implement the integer overflow checks in a much more
510        dynamic way, which I have now done. The artificial limitation on group
511        length has been removed - we now have only the limit on the total length of
512        the compiled pattern, which depends on the LINK_SIZE setting.
514    10. Fixed a bug in the documentation for get/copy named substring when
515        duplicate names are permitted. If none of the named substrings are set, the
516        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
517        empty string.
519    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
520        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
521        because the ] is interpreted as the first data character and the
522        terminating ] is not found. PCRE has been made compatible with Perl in this
523        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
524        cause memory overwriting.
526    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
527        string has been matched (to stop an infinite loop). It was not recognizing
528        a conditional subpattern that could match an empty string if that
529        subpattern was within another subpattern. For example, it looped when
530        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
531        condition was not nested. This bug has been fixed.
533    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
534        past the start of the subject in the presence of bytes with the top bit
535        set, for example "\x8aBCD".
537    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
538        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
540    14. Optimized (?!) to (*FAIL).
542    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
543        This restricts code points to be within the range 0 to 0x10FFFF, excluding
544        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
545        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
546        does: it's just the validity check that is more restrictive.
548    16. Inserted checks for integer overflows during escape sequence (backslash)
549        processing, and also fixed erroneous offset values for syntax errors during
550        backslash processing.
552    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
553        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
555    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
556        caused an overrun.
558    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
559        something other than just ASCII characters) inside a group that had an
560        unlimited repeat caused a loop at compile time (while checking to see
561        whether the group could match an empty string).
563    20. Debugging a pattern containing \p or \P could cause a crash. For example,
564        [\P{Any}] did so. (Error in the code for printing property names.)
566    21. An orphan \E inside a character class could cause a crash.
568    22. A repeated capturing bracket such as (A)? could cause a wild memory
569        reference during compilation.
571    23. There are several functions in pcre_compile() that scan along a compiled
572        expression for various reasons (e.g. to see if it's fixed length for look
573        behind). There were bugs in these functions when a repeated \p or \P was
574        present in the pattern. These operators have additional parameters compared
575        with \d, etc, and these were not being taken into account when moving along
576        the compiled data. Specifically:
578        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
579            length.
581        (b) An item such as \pL+ within a repeated group could cause crashes or
582            loops.
584        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
585            "reference to non-existent subpattern" error.
587        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
589    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
590        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
592    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
594    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
595        character were causing crashes (broken optimization).
597    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
598        \p or \P) caused a compile-time loop.
600    28. More problems have arisen in unanchored patterns when CRLF is a valid line
601        break. For example, the unstudied pattern [\r\n]A does not match the string
602        "\r\nA" because change 7.0/46 below moves the current point on by two
603        characters after failing to match at the start. However, the pattern \nA
604        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
605        the same is true. There doesn't seem any very clean way out of this, but
606        what I have chosen to do makes the common cases work: PCRE now takes note
607        of whether there can be an explicit match for \r or \n anywhere in the
608        pattern, and if so, 7.0/46 no longer applies. As part of this change,
609        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
610        pattern has explicit CR or LF references.
612    29. Added (*CR) etc for changing newline setting at start of pattern.
615    Version 7.2 19-Jun-07
616    ---------------------
618     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
619        which is apparently normally available under Windows.
621     2. Re-jig the pcregrep tests with different newline settings in an attempt
622        to make them independent of the local environment's newline setting.
624     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
626     4. Some of the "internals" tests were previously cut out when the link size
627        was not 2, because the output contained actual offsets. The recent new
628        "Z" feature of pcretest means that these can be cut out, making the tests
629        usable with all link sizes.
631     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
632        stack recursion. This gives a massive performance boost under BSD, but just
633        a small improvement under Linux. However, it saves one field in the frame
634        in all cases.
636     6. Added more features from the forthcoming Perl 5.10:
638        (a) (?-n) (where n is a string of digits) is a relative subroutine or
639            recursion call. It refers to the nth most recently opened parentheses.
641        (b) (?+n) is also a relative subroutine call; it refers to the nth next
642            to be opened parentheses.
644        (c) Conditions that refer to capturing parentheses can be specified
645            relatively, for example, (?(-2)... or (?(+3)...
647        (d) \K resets the start of the current match so that everything before
648            is not part of it.
650        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
652        (f) \g{name} is another synonym - part of Perl 5.10's unification of
653            reference syntax.
655        (g) (?| introduces a group in which the numbering of parentheses in each
656            alternative starts with the same number.
658        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
660     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
663     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
664        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
665        for detecting groups that can match an empty string.
667     9. A pattern with a very large number of alternatives (more than several
668        hundred) was running out of internal workspace during the pre-compile
669        phase, where pcre_compile() figures out how much memory will be needed. A
670        bit of new cunning has reduced the workspace needed for groups with
671        alternatives. The 1000-alternative test pattern now uses 12 bytes of
672        workspace instead of running out of the 4096 that are available.
674    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
676    11. Applied patch from Google to remove an optimization that didn't quite work.
677        The report of the bug said:
679          pcrecpp::RE("a*").FullMatch("aaa") matches, while
680          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
681          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
683    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
684        it matched the wrong number of bytes.
687    Version 7.1 24-Apr-07
688    ---------------------
690     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
691        that is more "standard", making use of automake and other Autotools. There
692        is some re-arrangement of the files and adjustment of comments consequent
693        on this.
695     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
696        for recursive directory scanning broke on some systems because the files
697        are not scanned in any specific order and on different systems the order
698        was different. A call to "sort" has been inserted into RunGrepTest for the
699        approprate test as a short-term fix. In the longer term there may be an
700        alternative.
702     3. I had an email from Eric Raymond about problems translating some of PCRE's
703        man pages to HTML (despite the fact that I distribute HTML pages, some
704        people do their own conversions for various reasons). The problems
705        concerned the use of low-level troff macros .br and .in. I have therefore
706        removed all such uses from the man pages (some were redundant, some could
707        be replaced by .nf/.fi pairs). The 132html script that I use to generate
708        HTML has been updated to handle .nf/.fi and to complain if it encounters
709        .br or .in.
711     4. Updated comments in configure.ac that get placed in config.h.in and also
712        arranged for config.h to be included in the distribution, with the name
713        config.h.generic, for the benefit of those who have to compile without
714        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
716     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
717        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
718        makevp.bat for the current PCRE, using the additional files
719        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
721     6. A Windows user reported a minor discrepancy with test 2, which turned out
722        to be caused by a trailing space on an input line that had got lost in his
723        copy. The trailing space was an accident, so I've just removed it.
725     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
726        that is needed.
728     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
729        as "const" (a) because they are and (b) because it helps the PHP
730        maintainers who have recently made a script to detect big data structures
731        in the php code that should be moved to the .rodata section. I remembered
732        to update Builducptable as well, so it won't revert if ucptable.h is ever
733        re-created.
735     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
736        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
737        order to be able to cut out the UTF-8 tables in the latter when UTF-8
738        support is not required. This saves 1.5-2K of code, which is important in
739        some applications.
741        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
742        so as not to refer to the tables, even though these functions will never be
743        called when UTF-8 support is disabled. Otherwise there are problems with a
744        shared library.
746    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
748        (a) It was defining its arguments as char * instead of void *.
750        (b) It was assuming that all moves were upwards in memory; this was true
751            a long time ago when I wrote it, but is no longer the case.
753        The emulated memove() is provided for those environments that have neither
754        memmove() nor bcopy(). I didn't think anyone used it these days, but that
755        is clearly not the case, as these two bugs were recently reported.
757    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
758        and Detrail to create the HTML documentation, the .txt form of the man
759        pages, and it removes trailing spaces from listed files. It also creates
760        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
761        case, it wraps all the #defines with #ifndefs. This script should be run
762        before "make dist".
764    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
765        with Unicode property support.
767        (a) For a maximizing quantifier, if the two different cases of the
768            character were of different lengths in their UTF-8 codings (there are
769            some cases like this - I found 11), and the matching function had to
770            back up over a mixture of the two cases, it incorrectly assumed they
771            were both the same length.
773        (b) When PCRE was configured to use the heap rather than the stack for
774            recursion during matching, it was not correctly preserving the data for
775            the other case of a UTF-8 character when checking ahead for a match
776            while processing a minimizing repeat. If the check also involved
777            matching a wide character, but failed, corruption could cause an
778            erroneous result when trying to check for a repeat of the original
779            character.
781    13. Some tidying changes to the testing mechanism:
783        (a) The RunTest script now detects the internal link size and whether there
784            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
785            values substituted by "configure". (The RunGrepTest script already did
786            this for UTF-8.) The configure.ac script no longer substitutes the
787            relevant variables.
789        (b) The debugging options /B and /D in pcretest show the compiled bytecode
790            with length and offset values. This means that the output is different
791            for different internal link sizes. Test 2 is skipped for link sizes
792            other than 2 because of this, bypassing the problem. Unfortunately,
793            there was also a test in test 3 (the locale tests) that used /B and
794            failed for link sizes other than 2. Rather than cut the whole test out,
795            I have added a new /Z option to pcretest that replaces the length and
796            offset values with spaces. This is now used to make test 3 independent
797            of link size. (Test 2 will be tidied up later.)
799    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
800        segmentation fault instead of returning the appropriate error message.
802    15. In multiline mode when the newline sequence was set to "any", the pattern
803        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
804        This doesn't seem right; it now treats the CRLF combination as the line
805        ending, and so does not match in that case. It's only a pattern such as ^$
806        that would hit this one: something like ^ABC$ would have failed after \r
807        and then tried again after \r\n.
809    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
810        in an attempt to make files that differ only in their line terminators
811        compare equal. This works on Linux.
813    17. Under certain error circumstances pcregrep might try to free random memory
814        as it exited. This is now fixed, thanks to valgrind.
816    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
817        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
818        was because its rules for how to advance for /g after matching an empty
819        string at the end of a line did not allow for this case. They now check for
820        it specially.
822    20. pcretest is supposed to handle patterns and data of any length, by
823        extending its buffers when necessary. It was getting this wrong when the
824        buffer for a data line had to be extended.
826    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
827        CRLF as a newline sequence.
829    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
830        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
831        I have nevertheless tidied it up.
833    23. Added some casts to kill warnings from HP-UX ia64 compiler.
835    24. Added a man page for pcre-config.
838    Version 7.0 19-Dec-06
839    ---------------------
841     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
842        moving to gcc 4.1.1.
844     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
845        sys/time.h, which is documented as needed for this function. It doesn't
846        seem to matter on Linux, but it showed up on some releases of OS X.
848     3. It seems that there are systems where bytes whose values are greater than
849        127 match isprint() in the "C" locale. The "C" locale should be the
850        default when a C program starts up. In most systems, only ASCII printing
851        characters match isprint(). This difference caused the output from pcretest
852        to vary, making some of the tests fail. I have changed pcretest so that:
854        (a) When it is outputting text in the compiled version of a pattern, bytes
855            other than 32-126 are always shown as hex escapes.
857        (b) When it is outputting text that is a matched part of a subject string,
858            it does the same, unless a different locale has been set for the match
859            (using the /L modifier). In this case, it uses isprint() to decide.
861     4. Fixed a major bug that caused incorrect computation of the amount of memory
862        required for a compiled pattern when options that changed within the
863        pattern affected the logic of the preliminary scan that determines the
864        length. The relevant options are -x, and -i in UTF-8 mode. The result was
865        that the computed length was too small. The symptoms of this bug were
866        either the PCRE error "internal error: code overflow" from pcre_compile(),
867        or a glibc crash with a message such as "pcretest: free(): invalid next
868        size (fast)". Examples of patterns that provoked this bug (shown in
869        pcretest format) are:
871          /(?-x: )/x
872          /(?x)(?-x: \s*#\s*)/
873          /((?i)[\x{c0}])/8
874          /(?i:[\x{c0}])/8
876        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
877        is now done differently.
879     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
880        wrapper classes; (b) implement a new function in the C++ scanner that is
881        more efficient than the old way of doing things because it avoids levels of
882        recursion in the regex matching; (c) add a paragraph to the documentation
883        for the FullMatch() function.
885     6. The escape sequence \n was being treated as whatever was defined as
886        "newline". Not only was this contrary to the documentation, which states
887        that \n is character 10 (hex 0A), but it also went horribly wrong when
888        "newline" was defined as CRLF. This has been fixed.
890     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
891        was being set to -1 for the "end of line" case (supposedly a value that no
892        character can have). Though this value is never used (the check for end of
893        line is "zero bytes in current character"), it caused compiler complaints.
894        I've changed it to 0xffffffff.
896     8. In pcre_version.c, the version string was being built by a sequence of
897        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
898        string (as it is for production releases) called a macro with an empty
899        argument. The C standard says the result of this is undefined. The gcc
900        compiler treats it as an empty string (which was what was wanted) but it is
901        reported that Visual C gives an error. The source has been hacked around to
902        avoid this problem.
904     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
905        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
906        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
907        of them did).
909    10. Originally, pcretest opened its input and output without "b"; then I was
910        told that "b" was needed in some environments, so it was added for release
911        5.0 to both the input and output. (It makes no difference on Unix-like
912        systems.) Later I was told that it is wrong for the input on Windows. I've
913        now abstracted the modes into two macros, to make it easier to fiddle with
914        them, and removed "b" from the input mode under Windows.
916    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
918    12. Added -help and --help to pcretest as an official way of being reminded
919        of the options.
921    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
922        and pcrecpp.cc because they annoy compilers at high warning levels.
924    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
926    15. Fixed an occurrence of == in configure.ac that should have been = (shell
927        scripts are not C programs :-) and which was not noticed because it works
928        on Linux.
930    16. pcretest is supposed to handle any length of pattern and data line (as one
931        line or as a continued sequence of lines) by extending its input buffer if
932        necessary. This feature was broken for very long pattern lines, leading to
933        a string of junk being passed to pcre_compile() if the pattern was longer
934        than about 50K.
936    17. I have done a major re-factoring of the way pcre_compile() computes the
937        amount of memory needed for a compiled pattern. Previously, there was code
938        that made a preliminary scan of the pattern in order to do this. That was
939        OK when PCRE was new, but as the facilities have expanded, it has become
940        harder and harder to keep it in step with the real compile phase, and there
941        have been a number of bugs (see for example, 4 above). I have now found a
942        cunning way of running the real compile function in a "fake" mode that
943        enables it to compute how much memory it would need, while actually only
944        ever using a few hundred bytes of working memory and without too many
945        tests of the mode. This should make future maintenance and development
946        easier. A side effect of this work is that the limit of 200 on the nesting
947        depth of parentheses has been removed (though this was never a serious
948        limitation, I suspect). However, there is a downside: pcre_compile() now
949        runs more slowly than before (30% or more, depending on the pattern). I
950        hope this isn't a big issue. There is no effect on runtime performance.
952    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
953        newline (only possible for the last line of a file) and it was a
954        pattern that set a locale (followed by /Lsomething), pcretest crashed.
956    19. Added additional timing features to pcretest. (1) The -tm option now times
957        matching only, not compiling. (2) Both -t and -tm can be followed, as a
958        separate command line item, by a number that specifies the number of
959        repeats to use when timing. The default is 50000; this gives better
960        precision, but takes uncomfortably long for very large patterns.
962    20. Extended pcre_study() to be more clever in cases where a branch of a
963        subpattern has no definite first character. For example, (a*|b*)[cd] would
964        previously give no result from pcre_study(). Now it recognizes that the
965        first character must be a, b, c, or d.
967    21. There was an incorrect error "recursive call could loop indefinitely" if
968        a subpattern (or the entire pattern) that was being tested for matching an
969        empty string contained only one non-empty item after a nested subpattern.
970        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
971        incorrectly, because the \d was being skipped in the check.
973    22. The pcretest program now has a new pattern option /B and a command line
974        option -b, which is equivalent to adding /B to every pattern. This causes
975        it to show the compiled bytecode, without the additional information that
976        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
977        is the same as /B/I).
979    23. A new optimization is now able automatically to treat some sequences such
980        as a*b as a*+b. More specifically, if something simple (such as a character
981        or a simple class like \d) has an unlimited quantifier, and is followed by
982        something that cannot possibly match the quantified thing, the quantifier
983        is automatically "possessified".
985    24. A recursive reference to a subpattern whose number was greater than 39
986        went wrong under certain circumstances in UTF-8 mode. This bug could also
987        have affected the operation of pcre_study().
989    25. Realized that a little bit of performance could be had by replacing
990        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
992    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
994    27. Possessive quantifiers such as a++ were previously implemented by turning
995        them into atomic groups such as ($>a+). Now they have their own opcodes,
996        which improves performance. This includes the automatically created ones
997        from 23 above.
999    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1000        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1001        the first matched character to be a colon. This applied both to named and
1002        numbered groups.
1004    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1006    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1007        building PCRE on Windows easier, so I have included it in the distribution.
1009    31. There is now a check in pcretest against a ridiculously large number being
1010        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1011        loop, the loop is abandoned.
1013    32. Forward references to subpatterns in conditions such as (?(2)...) where
1014        subpattern 2 is defined later cause pcre_compile() to search forwards in
1015        the pattern for the relevant set of parentheses. This search went wrong
1016        when there were unescaped parentheses in a character class, parentheses
1017        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1019    33. "Subroutine" calls and backreferences were previously restricted to
1020        referencing subpatterns earlier in the regex. This restriction has now
1021        been removed.
1023    34. Added a number of extra features that are going to be in Perl 5.10. On the
1024        whole, these are just syntactic alternatives for features that PCRE had
1025        previously implemented using the Python syntax or my own invention. The
1026        other formats are all retained for compatibility.
1028        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1029            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1030            also .NET compatible.
1032        (b) A recursion or subroutine call to a named group can now be defined as
1033            (?&name) as well as (?P>name).
1035        (c) A backreference to a named group can now be defined as \k<name> or
1036            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1037            5.10, are also .NET compatible.
1039        (d) A conditional reference to a named group can now use the syntax
1040            (?(<name>) or (?('name') as well as (?(name).
1042        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1043            groups (named and numbered) that are never evaluated inline, but can be
1044            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1045            is always false. There may be only one alternative in such a group.
1047        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1048            as the simple (?(R). The condition is true only if the most recent
1049            recursion is that of the given number or name. It does not search out
1050            through the entire recursion stack.
1052        (g) The escape \gN or \g{N} has been added, where N is a positive or
1053            negative number, specifying an absolute or relative reference.
1055    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1056        some "unreachable code" warnings.
1058    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1059        things, this adds five new scripts.
1061    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1062        There were also incompatibilities regarding the handling of \Q..\E inside
1063        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1064        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1066    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1067        matches an empty string, and forcibly breaks the loop. There were bugs in
1068        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1069        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1070        separate and independent bugs (that affected different cases) have been
1071        fixed.
1073    39. Refactored the code to abolish the use of different opcodes for small
1074        capturing bracket numbers. This is a tidy that I avoided doing when I
1075        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1076        The new approach is not only tidier, it makes it possible to reduce the
1077        memory needed to fix the previous bug (38).
1079    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1080        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1081        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1082        mode.
1084    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1085        report.
1087    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1088        copy construction and assignment in the C++ wrapper.
1090    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1091        couple of bugs that could have given wrong results in the "--newline=crlf"
1092        case.
1094    44. Added a number of casts and did some reorganization of signed/unsigned int
1095        variables following suggestions from Dair Grant. Also renamed the variable
1096        "this" as "item" because it is a C++ keyword.
1098    45. Arranged for dftables to add
1100          #include "pcre_internal.h"
1102        to pcre_chartables.c because without it, gcc 4.x may remove the array
1103        definition from the final binary if PCRE is built into a static library and
1104        dead code stripping is activated.
1106    46. For an unanchored pattern, if a match attempt fails at the start of a
1107        newline sequence, and the newline setting is CRLF or ANY, and the next two
1108        characters are CRLF, advance by two characters instead of one.
1111    Version 6.7 04-Jul-06
1112    ---------------------
1114     1. In order to handle tests when input lines are enormously long, pcretest has
1115        been re-factored so that it automatically extends its buffers when
1116        necessary. The code is crude, but this _is_ just a test program. The
1117        default size has been increased from 32K to 50K.
1119     2. The code in pcre_study() was using the value of the re argument before
1120        testing it for NULL. (Of course, in any sensible call of the function, it
1121        won't be NULL.)
1123     3. The memmove() emulation function in pcre_internal.h, which is used on
1124        systems that lack both memmove() and bcopy() - that is, hardly ever -
1125        was missing a "static" storage class specifier.
1127     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1128        containing an extended class (one that cannot be represented by a bitmap
1129        because it contains high-valued characters or Unicode property items, e.g.
1130        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1131        pattern, but PCRE should not loop if you do not (it no longer does).
1132        [Detail: two cases were found: (a) a repeated subpattern containing an
1133        extended class; (b) a recursive reference to a subpattern that followed a
1134        previous extended class. It wasn't skipping over the extended class
1135        correctly when UTF-8 mode was not set.]
1137     5. A negated single-character class was not being recognized as fixed-length
1138        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1139        compile error "lookbehind assertion is not fixed length".
1141     6. The RunPerlTest auxiliary script was showing an unexpected difference
1142        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1143        write a Perl script that can interpret lines of an input file either as
1144        byte characters or as UTF-8, which is what "perltest" was being required to
1145        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1146        can't do is switch easily at run time between having the "use utf8;" pragma
1147        or not. In the end, I fudged it by using the RunPerlTest script to insert
1148        "use utf8;" explicitly for the UTF-8 tests.
1150     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1151        the end of the subject string, contrary to the documentation and to what
1152        Perl does. This was true of both matching functions. Now it matches only at
1153        the start of the subject and immediately after *internal* newlines.
1155     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1156        a pointer to an int instead of a pointer to an unsigned long int. This
1157        caused problems on 64-bit systems.
1159     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1160        instance of the 'standard' template library not being so standard".
1162    10. There was no check on the number of named subpatterns nor the maximum
1163        length of a subpattern name. The product of these values is used to compute
1164        the size of the memory block for a compiled pattern. By supplying a very
1165        long subpattern name and a large number of named subpatterns, the size
1166        computation could be caused to overflow. This is now prevented by limiting
1167        the length of names to 32 characters, and the number of named subpatterns
1168        to 10,000.
1170    11. Subpatterns that are repeated with specific counts have to be replicated in
1171        the compiled pattern. The size of memory for this was computed from the
1172        length of the subpattern and the repeat count. The latter is limited to
1173        65535, but there was no limit on the former, meaning that integer overflow
1174        could in principle occur. The compiled length of a repeated subpattern is
1175        now limited to 30,000 bytes in order to prevent this.
1177    12. Added the optional facility to have named substrings with the same name.
1179    13. Added the ability to use a named substring as a condition, using the
1180        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1181        are numbers (not recommended). Forward references are permitted.
1183    14. Added forward references in named backreferences (if you see what I mean).
1185    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1186        pattern could run off the end of the subject. For example, the pattern
1187        "(?s)(.{1,5})"8 did this with the subject "ab".
1189    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1190        PCRE_CASELESS was set when matching characters that were quantified with ?
1191        or *.
1193    17. A character class other than a single negated character that had a minimum
1194        but no maximum quantifier - for example [ab]{6,} - was not handled
1195        correctly by pce_dfa_exec(). It would match only one character.
1197    18. A valid (though odd) pattern that looked like a POSIX character
1198        class but used an invalid character after [ (for example [[,abc,]]) caused
1199        pcre_compile() to give the error "Failed: internal error: code overflow" or
1200        in some cases to crash with a glibc free() error. This could even happen if
1201        the pattern terminated after [[ but there just happened to be a sequence of
1202        letters, a binary zero, and a closing ] in the memory that followed.
1204    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1205        over the years. Originally (before any Unicode support), just the bottom 8
1206        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1207        output from "man perlunicode" includes this:
1209          The regular expression compiler produces polymorphic opcodes.  That
1210          is, the pattern adapts to the data and automatically switches to
1211          the Unicode character scheme when presented with Unicode data--or
1212          instead uses a traditional byte scheme when presented with byte
1213          data.
1215        Sadly, a wide octal escape does not cause a switch, and in a string with
1216        no other multibyte characters, these octal escapes are treated as before.
1217        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1218        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1219        Unicode string.
1221        I have not perpetrated such confusion in PCRE. Up till now, it took just
1222        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1223        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1224        translate to the appropriate multibyte character.
1226    29. Applied some refactoring to reduce the number of warnings from Microsoft
1227        and Borland compilers. This has included removing the fudge introduced
1228        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1229        a warning about an unused variable.
1231    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1232        characters since release 4.0, because Perl (from release 5.004) does not.
1233        [Or at least, is documented not to: some releases seem to be in conflict
1234        with the documentation.] However, when a pattern was studied with
1235        pcre_study() and all its branches started with \s, PCRE still included VT
1236        as a possible starting character. Of course, this did no harm; it just
1237        caused an unnecessary match attempt.
1239    22. Removed a now-redundant internal flag bit that recorded the fact that case
1240        dependency changed within the pattern. This was once needed for "required
1241        byte" processing, but is no longer used. This recovers a now-scarce options
1242        bit. Also moved the least significant internal flag bit to the most-
1243        significant bit of the word, which was not previously used (hangover from
1244        the days when it was an int rather than a uint) to free up another bit for
1245        the future.
1247    23. Added support for CRLF line endings as well as CR and LF. As well as the
1248        default being selectable at build time, it can now be changed at runtime
1249        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1250        specify that it is scanning data with non-default line endings.
1252    24. Changed the definition of CXXLINK to make it agree with the definition of
1253        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1255    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1256        recursions. This makes a big different to stack usage for some patterns.
1258    26. If a subpattern containing a named recursion or subroutine reference such
1259        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1260        the space required for the compiled pattern went wrong and gave too small a
1261        value. Depending on the environment, this could lead to "Failed: internal
1262        error: code overflow at offset 49" or "glibc detected double free or
1263        corruption" errors.
1265    27. Applied patches from Google (a) to support the new newline modes and (b) to
1266        advance over multibyte UTF-8 characters in GlobalReplace.
1268    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1269        difference for some implementation of PCRE in some Windows version.
1271    29. Added some extra testing facilities to pcretest:
1273        \q<number>   in a data line sets the "match limit" value
1274        \Q<number>   in a data line sets the "match recursion limt" value
1275        -S <number>  sets the stack size, where <number> is in megabytes
1277        The -S option isn't available for Windows.
1280    Version 6.6 06-Feb-06
1281    ---------------------
1283     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1284        in pcreposix.h. I have copied the definition from pcre.h.
1286     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1287        because pcre.h is no longer a built file.
1289     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1290        not normally included in the compiled code.
1293    Version 6.5 01-Feb-06
1294    ---------------------
1296     1. When using the partial match feature with pcre_dfa_exec(), it was not
1297        anchoring the second and subsequent partial matches at the new starting
1298        point. This could lead to incorrect results. For example, with the pattern
1299        /1234/, partially matching against "123" and then "a4" gave a match.
1301     2. Changes to pcregrep:
1303        (a) All non-match returns from pcre_exec() were being treated as failures
1304            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1305            error message is output. Some extra information is given for the
1306            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1307            probably the only errors that are likely to be caused by users (by
1308            specifying a regex that has nested indefinite repeats, for instance).
1309            If there are more than 20 of these errors, pcregrep is abandoned.
1311        (b) A binary zero was treated as data while matching, but terminated the
1312            output line if it was written out. This has been fixed: binary zeroes
1313            are now no different to any other data bytes.
1315        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1316            used to set a locale for matching. The --locale=xxxx long option has
1317            been added (no short equivalent) to specify a locale explicitly on the
1318            pcregrep command, overriding the environment variables.
1320        (d) When -B was used with -n, some line numbers in the output were one less
1321            than they should have been.
1323        (e) Added the -o (--only-matching) option.
1325        (f) If -A or -C was used with -c (count only), some lines of context were
1326            accidentally printed for the final match.
1328        (g) Added the -H (--with-filename) option.
1330        (h) The combination of options -rh failed to suppress file names for files
1331            that were found from directory arguments.
1333        (i) Added the -D (--devices) and -d (--directories) options.
1335        (j) Added the -F (--fixed-strings) option.
1337        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1339        (l) Added the --colo(u)r option.
1341        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1342            is not present by default.
1344     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1345        items such as (?R) or (?1), when the recursion could match a number of
1346        alternatives. If it matched one of the alternatives, but subsequently,
1347        outside the recursion, there was a failure, the code tried to back up into
1348        the recursion. However, because of the way PCRE is implemented, this is not
1349        possible, and the result was an incorrect result from the match.
1351        In order to prevent this happening, the specification of recursion has
1352        been changed so that all such subpatterns are automatically treated as
1353        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1355     4. I had overlooked the fact that, in some locales, there are characters for
1356        which isalpha() is true but neither isupper() nor islower() are true. In
1357        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1358        and ordfeminine) are like this. This affected the treatment of \w and \W
1359        when they appeared in character classes, but not when they appeared outside
1360        a character class. The bit map for "word" characters is now created
1361        separately from the results of isalnum() instead of just taking it from the
1362        upper, lower, and digit maps. (Plus the underscore character, of course.)
1364     5. The above bug also affected the handling of POSIX character classes such as
1365        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1366        permanent tables. Instead, the bit maps for such a class were previously
1367        created as the appropriate unions of the upper, lower, and digit bitmaps.
1368        Now they are created by subtraction from the [[:word:]] class, which has
1369        its own bitmap.
1371     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1372        It is created by subtracting the vertical space characters (\x09, \x0a,
1373        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1374        subtraction was done in the overall bitmap for a character class, meaning
1375        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1376        be recognized. This bug has been fixed.
1378     7. Patches from the folks at Google:
1380          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1381          real life, but is still worth protecting against".
1383          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1384          regular expressions".
1386          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1387          have it.
1389          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1390          "configure" and the latter not, in order to fix a problem somebody had
1391          with compiling the Arg class on HP-UX.
1393          (e) Improve the error-handling of the C++ wrapper a little bit.
1395          (f) New tests for checking recursion limiting.
1397     8. The pcre_memmove() function, which is used only if the environment does not
1398        have a standard memmove() function (and is therefore rarely compiled),
1399        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1400        returning a result (though PCRE never actually uses the result).
1402     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1403        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1404        returned instead of calling malloc() with an overflowing number that would
1405        most likely cause subsequent chaos.
1407    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1409    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1410        with this option is matched, the nmatch and pmatch options of regexec() are
1411        ignored.
1413    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1414        provided in case anyone wants to the the POSIX interface with UTF-8
1415        strings.
1417    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1418        C++ linking (needed for some HP-UX environments).
1420    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1421        (unused parameter) and in the pcre_printint() function (omitted "default"
1422        switch label when the default is to do nothing).
1424    15. Added some code to make it possible, when PCRE is compiled as a C++
1425        library, to replace subject pointers for pcre_exec() with a smart pointer
1426        class, thus making it possible to process discontinuous strings.
1428    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1429        much the same function. They were added by different people who were trying
1430        to make PCRE easy to compile on non-Unix systems. It has been suggested
1431        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1432        for compiling on Windows systems. I have therefore replaced it with
1433        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1434        defaults to "extern" for C or "extern C" for C++, which works fine on
1435        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1436        SCOPE with something explicit in config.h. In addition:
1438        (a) pcreposix.h still had just "extern" instead of either of these macros;
1439            I have replaced it with PCRE_DATA_SCOPE.
1441        (b) Functions such as _pcre_xclass(), which are internal to the library,
1442            but external in the C sense, all had PCRE_EXPORT in their definitions.
1443            This is apparently wrong for the Windows case, so I have removed it.
1444            (It makes no difference on Unix-like systems.)
1446    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1447        of recursive calls to match(). This is different to MATCH_LIMIT because
1448        that limits the total number of calls to match(), not all of which increase
1449        the depth of recursion. Limiting the recursion depth limits the amount of
1450        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1451        when PCRE is compiled, and changed at run time. A patch from Google adds
1452        this functionality to the C++ interface.
1454    18. Changes to the handling of Unicode character properties:
1456        (a) Updated the table to Unicode 4.1.0.
1458        (b) Recognize characters that are not in the table as "Cn" (undefined).
1460        (c) I revised the way the table is implemented to a much improved format
1461            which includes recognition of ranges. It now supports the ranges that
1462            are defined in UnicodeData.txt, and it also amalgamates other
1463            characters into ranges. This has reduced the number of entries in the
1464            table from around 16,000 to around 3,000, thus reducing its size
1465            considerably. I realized I did not need to use a tree structure after
1466            all - a binary chop search is just as efficient. Having reduced the
1467            number of entries, I extended their size from 6 bytes to 8 bytes to
1468            allow for more data.
1470        (d) Added support for Unicode script names via properties such as \p{Han}.
1472    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1473        matching that character.
1475    20. When matching a repeated Unicode property with a minimum greater than zero,
1476        (for example \pL{2,}), PCRE could look past the end of the subject if it
1477        reached it while seeking the minimum number of characters. This could
1478        happen only if some of the characters were more than one byte long, because
1479        there is a check for at least the minimum number of bytes.
1481    21. Refactored the implementation of \p and \P so as to be more general, to
1482        allow for more different types of property in future. This has changed the
1483        compiled form incompatibly. Anybody with saved compiled patterns that use
1484        \p or \P will have to recompile them.
1486    22. Added "Any" and "L&" to the supported property types.
1488    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1489        but give a compile time error if the value is greater than 0xff.
1491    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1492        accidentally not being installed or uninstalled.
1494    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1495        made were to insert the current release number. This seemed silly, because
1496        it made things harder for people building PCRE on systems that don't run
1497        "configure". I have turned pcre.h into a distributed file, no longer built
1498        by "configure", with the version identification directly included. There is
1499        no longer a pcre.h.in file.
1501        However, this change necessitated a change to the pcre-config script as
1502        well. It is built from pcre-config.in, and one of the substitutions was the
1503        release number. I have updated configure.ac so that ./configure now finds
1504        the release number by grepping pcre.h.
1506    26. Added the ability to run the tests under valgrind.
1509    Version 6.4 05-Sep-05
1510    ---------------------
1512     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1513        "--" to be printed when multiple files were scanned, even when none of the
1514        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1515        consider it to be a bug, and have restored the previous behaviour.
1517     2. A couple of code tidies to get rid of compiler warnings.
1519     3. The pcretest program used to cheat by referring to symbols in the library
1520        whose names begin with _pcre_. These are internal symbols that are not
1521        really supposed to be visible externally, and in some environments it is
1522        possible to suppress them. The cheating is now confined to including
1523        certain files from the library's source, which is a bit cleaner.
1525     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1526        file's purpose clearer.
1528     5. Reorganized pcre_ucp_findchar().
1531    Version 6.3 15-Aug-05
1532    ---------------------
1534     1. The file libpcre.pc.in did not have general read permission in the tarball.
1536     2. There were some problems when building without C++ support:
1538        (a) If C++ support was not built, "make install" and "make test" still
1539            tried to test it.
1541        (b) There were problems when the value of CXX was explicitly set. Some
1542            changes have been made to try to fix these, and ...
1544        (c) --disable-cpp can now be used to explicitly disable C++ support.
1546        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1547            backslash in a target when C++ was disabled. This confuses some
1548            versions of "make", apparently. Using an intermediate variable solves
1549            this. (Same for CPP_LOBJ.)
1551     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1552        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1553        necessary on certain architectures.
1555     4. Added a setting of -export-symbols-regex to the link command to remove
1556        those symbols that are exported in the C sense, but actually are local
1557        within the library, and not documented. Their names all begin with
1558        "_pcre_". This is not a perfect job, because (a) we have to except some
1559        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1560        available (and never for static libraries). I have made a note to try to
1561        find a way round (a) in the future.
1564    Version 6.2 01-Aug-05
1565    ---------------------
1567     1. There was no test for integer overflow of quantifier values. A construction
1568        such as {1111111111111111} would give undefined results. What is worse, if
1569        a minimum quantifier for a parenthesized subpattern overflowed and became
1570        negative, the calculation of the memory size went wrong. This could have
1571        led to memory overwriting.
1573     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1575     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1576        operating environments where this matters.
1578     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1579        PCRE options from within the C++ wrapper.
1581     5. Named capturing subpatterns were not being correctly counted when a pattern
1582        was compiled. This caused two problems: (a) If there were more than 100
1583        such subpatterns, the calculation of the memory needed for the whole
1584        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1585        back references of the form \12, where the number was greater than 9, were
1586        not recognized as back references, even though there were sufficient
1587        previous subpatterns.
1589     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1590        versions of gcc, e.g. 2.95.4.
1593    Version 6.1 21-Jun-05
1594    ---------------------
1596     1. There was one reference to the variable "posix" in pcretest.c that was not
1597        surrounded by "#if !defined NOPOSIX".
1599     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1600        the cross-check on the old pcre_info() function, for the benefit of the
1601        cut-down version of PCRE that is currently imported into Exim.
1603     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1604        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1605        patterns that start (?i) but I don't think that matters. The use of (?i) is
1606        just an example; this all applies to the other options as well.
1608     4. Since libtool seems to echo the compile commands it is issuing, the output
1609        from "make" can be reduced a bit by putting "@" in front of each libtool
1610        compile command.
1612     5. Patch from the folks at Google for configure.in to be a bit more thorough
1613        in checking for a suitable C++ installation before trying to compile the
1614        C++ stuff. This should fix a reported problem when a compiler was present,
1615        but no suitable headers.
1617     6. The man pages all had just "PCRE" as their title. I have changed them to
1618        be the relevant file name. I have also arranged that these names are
1619        retained in the file doc/pcre.txt, which is a concatenation in text format
1620        of all the man pages except the little individual ones for each function.
1622     7. The NON-UNIX-USE file had not been updated for the different set of source
1623        files that come with release 6. I also added a few comments about the C++
1624        wrapper.
1627    Version 6.0 07-Jun-05
1628    ---------------------
1630     1. Some minor internal re-organization to help with my DFA experiments.
1632     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1633        didn't matter for the library itself when fully configured, but did matter
1634        when compiling without UCP support, or within Exim, where the ucp files are
1635        not imported.
1637     3. Refactoring of the library code to split up the various functions into
1638        different source modules. The addition of the new DFA matching code (see
1639        below) to a single monolithic source would have made it really too
1640        unwieldy, quite apart from causing all the code to be include in a
1641        statically linked application, when only some functions are used. This is
1642        relevant even without the DFA addition now that patterns can be compiled in
1643        one application and matched in another.
1645        The downside of splitting up is that there have to be some external
1646        functions and data tables that are used internally in different modules of
1647        the library but which are not part of the API. These have all had their
1648        names changed to start with "_pcre_" so that they are unlikely to clash
1649        with other external names.
1651     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1652        a different (DFA) algorithm. Although it is slower than the original
1653        function, it does have some advantages for certain types of matching
1654        problem.
1656     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1657        including restarting after a partial match.
1659     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1660        defined when compiling for Windows was sent to me. I have put it into the
1661        code, though I have no means of testing or verifying it.
1663     7. Added the pcre_refcount() auxiliary function.
1665     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1666        match before or at the first newline in the subject string. In pcretest,
1667        the /f option on a pattern can be used to set this.
1669     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1670        would behave wrongly. This has been present in PCRE since release 4.0.
1672    10. A number of changes to the pcregrep command:
1674        (a) Refactored how -x works; insert ^(...)$ instead of setting
1675            PCRE_ANCHORED and checking the length, in preparation for adding
1676            something similar for -w.
1678        (b) Added the -w (match as a word) option.
1680        (c) Refactored the way lines are read and buffered so as to have more
1681            than one at a time available.
1683        (d) Implemented a pcregrep test script.
1685        (e) Added the -M (multiline match) option. This allows patterns to match
1686            over several lines of the subject. The buffering ensures that at least
1687            8K, or the rest of the document (whichever is the shorter) is available
1688            for matching (and similarly the previous 8K for lookbehind assertions).
1690        (f) Changed the --help output so that it now says
1692              -w, --word-regex(p)
1694            instead of two lines, one with "regex" and the other with "regexp"
1695            because that confused at least one person since the short forms are the
1696            same. (This required a bit of code, as the output is generated
1697            automatically from a table. It wasn't just a text change.)
1699        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1700            option but starts with a hyphen. Could be a pattern or a path name
1701            starting with a hyphen, for instance.
1703        (h) "-" can be given as a file name to represent stdin.
1705        (i) When file names are being printed, "(standard input)" is used for
1706            the standard input, for compatibility with GNU grep. Previously
1707            "<stdin>" was used.
1709        (j) The option --label=xxx can be used to supply a name to be used for
1710            stdin when file names are being printed. There is no short form.
1712        (k) Re-factored the options decoding logic because we are going to add
1713            two more options that take data. Such options can now be given in four
1714            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1716        (l) Added the -A, -B, and -C options for requesting that lines of context
1717            around matches be printed.
1719        (m) Added the -L option to print the names of files that do not contain
1720            any matching lines, that is, the complement of -l.
1722        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1723            continue to scan other files.
1725        (o) The -s option was incorrectly implemented. For compatibility with other
1726            greps, it now suppresses the error message for a non-existent or non-
1727            accessible file (but not the return code). There is a new option called
1728            -q that suppresses the output of matching lines, which was what -s was
1729            previously doing.
1731        (p) Added --include and --exclude options to specify files for inclusion
1732            and exclusion when recursing.
1734    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1735        Hopefully, it now does.
1737    12. Missing cast in pcre_study().
1739    13. Added an "uninstall" target to the makefile.
1741    14. Replaced "extern" in the function prototypes in Makefile.in with
1742        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1743        world, but is set differently for Windows.
1745    15. Added a second compiling function called pcre_compile2(). The only
1746        difference is that it has an extra argument, which is a pointer to an
1747        integer error code. When there is a compile-time failure, this is set
1748        non-zero, in addition to the error test pointer being set to point to an
1749        error message. The new argument may be NULL if no error number is required
1750        (but then you may as well call pcre_compile(), which is now just a
1751        wrapper). This facility is provided because some applications need a
1752        numeric error indication, but it has also enabled me to tidy up the way
1753        compile-time errors are handled in the POSIX wrapper.
1755    16. Added VPATH=.libs to the makefile; this should help when building with one
1756        prefix path and installing with another. (Or so I'm told by someone who
1757        knows more about this stuff than I do.)
1759    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1760        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1761        match everything, including newlines. This is not POSIX-compatible, but
1762        somebody wanted the feature. From pcretest it can be activated by using
1763        both the P and the s flags.
1765    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1767    19. libpcre.pc was being incorrectly installed as executable.
1769    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1770        it now also looks for '\r' so that it will work unmodified on Windows.
1772    21. Added Google's contributed C++ wrapper to the distribution.
1774    22. Added some untidy missing memory free() calls in pcretest, to keep
1775        Electric Fence happy when testing.
1779    Version 5.0 13-Sep-04
1780    ---------------------
1782     1. Internal change: literal characters are no longer packed up into items
1783        containing multiple characters in a single byte-string. Each character
1784        is now matched using a separate opcode. However, there may be more than one
1785        byte in the character in UTF-8 mode.
1787     2. The pcre_callout_block structure has two new fields: pattern_position and
1788        next_item_length. These contain the offset in the pattern to the next match
1789        item, and its length, respectively.
1791     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1792        insertion of callouts before each pattern item. Added the /C option to
1793        pcretest to make use of this.
1795     4. On the advice of a Windows user, the lines
1797          #if defined(_WIN32) || defined(WIN32)
1798          _setmode( _fileno( stdout ), 0x8000 );
1799          #endif  /* defined(_WIN32) || defined(WIN32) */
1801        have been added to the source of pcretest. This apparently does useful
1802        magic in relation to line terminators.
1804     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1805        for the benefit of those environments where the "b" makes a difference.
1807     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1808        to know about it. I have put a hack into configure.in that adds in code
1809        to set GCC=yes if CC=icc. This seems to end up at a point in the
1810        generated configure script that is early enough to affect the setting of
1811        compiler options, which is what is needed, but I have no means of testing
1812        whether it really works. (The user who reported this had patched the
1813        generated configure script, which of course I cannot do.)
1815        LATER: After change 22 below (new libtool files), the configure script
1816        seems to know about icc (and also ecc). Therefore, I have commented out
1817        this hack in configure.in.
1819     7. Added support for pkg-config (2 patches were sent in).
1821     8. Negated POSIX character classes that used a combination of internal tables
1822        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1823        [[:^ascii]]. Typically, they would match almost any characters. The other
1824        POSIX classes were not broken in this way.
1826     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1827        to find the match, as PCRE was deluded into thinking that the match had to
1828        start at the start point or following a newline. The same bug applied to
1829        patterns with negative forward assertions or any backward assertions
1830        preceding ".*" at the start, unless the pattern required a fixed first
1831        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1833    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1834        starting at the last subject character, bytes beyond the end of the subject
1835        string were read.
1837    11. Renamed the variable "class" as "classbits" to make life easier for C++
1838        users. (Previously there was a macro definition, but it apparently wasn't
1839        enough.)
1841    12. Added the new field "tables" to the extra data so that tables can be passed
1842        in at exec time, or the internal tables can be re-selected. This allows
1843        a compiled regex to be saved and re-used at a later time by a different
1844        program that might have everything at different addresses.
1846    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1847        -R library as well as a -L library.
1849    14. The debugging options of pcretest (-d on the command line or D on a
1850        pattern) showed incorrect output for anything following an extended class
1851        that contained multibyte characters and which was followed by a quantifier.
1853    15. Added optional support for general category Unicode character properties
1854        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1855        support. It adds about 90K to the size of the library. The meanings of the
1856        inbuilt class escapes such as \d and \s have NOT been changed.
1858    16. Updated pcredemo.c to include calls to free() to release the memory for the
1859        compiled pattern.
1861    17. The generated file chartables.c was being created in the source directory
1862        instead of in the building directory. This caused the build to fail if the
1863        source directory was different from the building directory, and was
1864        read-only.
1866    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1867        file. No doubt somebody will tell me if they don't make sense... Also added
1868        Dan Mooney's comments about building on OpenVMS.
1870    19. Added support for partial matching via the PCRE_PARTIAL option for
1871        pcre_exec() and the \P data escape in pcretest.
1873    20. Extended pcretest with 3 new pattern features:
1875        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1876              write the compiled pattern to the file whose name is "rest-of-line".
1877              This is a straight binary dump of the data, with the saved pointer to
1878              the character tables forced to be NULL. The study data, if any, is
1879              written too. After writing, pcretest reads a new pattern.
1881        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1882              compiled pattern from the given file. There must not be any
1883              occurrences of "<" in the file name (pretty unlikely); if there are,
1884              pcretest will instead treat the initial "<" as a pattern delimiter.
1885              After reading in the pattern, pcretest goes on to read data lines as
1886              usual.
1888        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1889              and 16-bit fields in a compiled pattern, to simulate a pattern that
1890              was compiled on a host of opposite endianness.
1892    21. The pcre-exec() function can now cope with patterns that were compiled on
1893        hosts of opposite endianness, with this restriction:
1895          As for any compiled expression that is saved and used later, the tables
1896          pointer field cannot be preserved; the extra_data field in the arguments
1897          to pcre_exec() should be used to pass in a tables address if a value
1898          other than the default internal tables were used at compile time.
1900    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1901        now diagnosed as an error. Previously, most of the time, a negative number
1902        would have been treated as zero, but if in addition "ovector" was passed as
1903        NULL, a crash could occur.
1905    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1906        new versions from the libtool 1.5 distribution (the last one is a copy of
1907        a file called libtool.m4). This seems to have fixed the need to patch
1908        "configure" to support Darwin 1.3 (which I used to do). However, I still
1909        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1910        workstation).
1912    24. Changed the PCRE licence to be the more standard "BSD" licence.
1915    Version 4.5 01-Dec-03
1916    ---------------------
1918     1. There has been some re-arrangement of the code for the match() function so
1919        that it can be compiled in a version that does not call itself recursively.
1920        Instead, it keeps those local variables that need separate instances for
1921        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1922        needs to "recurse". Keeping track of where control must go is done by means
1923        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1924        hide most of the details from the main code, and operates only if
1925        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1926        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1927        operating.
1929        To make it easier for callers to provide specially tailored get/free
1930        functions for this usage, two new functions, pcre_stack_malloc, and
1931        pcre_stack_free, are used. They are always called in strict stacking order,
1932        and the size of block requested is always the same.
1934        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1935        PCRE has been compiled to use the stack or the heap for recursion. The
1936        -C option of pcretest uses this to show which version is compiled.
1938        A new data escape \S, is added to pcretest; it causes the amounts of store
1939        obtained and freed by both kinds of malloc/free at match time to be added
1940        to the output.
1942     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1943        what's available on my current Linux desktop machine.
1945     3. When matching a UTF-8 string, the test for a valid string at the start has
1946        been extended. If start_offset is not zero, PCRE now checks that it points
1947        to a byte that is the start of a UTF-8 character. If not, it returns
1948        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1949        this is necessary because there may be backward assertions in the pattern.
1950        When matching the same subject several times, it may save resources to use
1951        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1953     4. The code for checking the validity of UTF-8 strings has been tightened so
1954        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1955        containing "overlong sequences".
1957     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1958        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1959        should have been "&", but it just so happened that all the cases this let
1960        through by mistake were picked up later in the function.
1962     6. I had used a variable called "isblank" - this is a C99 function, causing
1963        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1965     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1966        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1967        so the version is shown; (c) stop "make test" echoing "./RunTest".
1969     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1971     9. The prototype for memmove() for systems that don't have it was using
1972        size_t, but the inclusion of the header that defines size_t was later. I've
1973        moved the #includes for the C headers earlier to avoid this.
1975    10. Added some adjustments to the code to make it easier to compiler on certain
1976        special systems:
1978          (a) Some "const" qualifiers were missing.
1979          (b) Added the macro EXPORT before all exported functions; by default this
1980              is defined to be empty.
1981          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1982              that it reads its output file name as an argument instead of writing
1983              to the standard output and assuming this can be redirected.
1985    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1986        class containing characters with values greater than 255, PCRE compilation
1987        went into a loop.
1989    12. A recursive reference to a subpattern that was within another subpattern
1990        that had a minimum quantifier of zero caused PCRE to crash. For example,
1991        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1992        recursion. If the recursively-called subpattern itself had a zero repeat,
1993        that was OK.
1995    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1996        buffer into which it was copied (for escape processing) was still set at
1997        1024, so long lines caused crashes.
1999    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2000        "internal error: code overflow...". This applied to any character class
2001        that was followed by a possessive quantifier.
2003    15. Modified the Makefile to add libpcre.la as a prerequisite for
2004        libpcreposix.la because I was told this is needed for a parallel build to
2005        work.
2007    16. If a pattern that contained .* following optional items at the start was
2008        studied, the wrong optimizing data was generated, leading to matching
2009        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2010        matching string must start with a or b or c. The correct conclusion for
2011        this pattern is that a match can start with any character.
2014    Version 4.4 13-Aug-03
2015    ---------------------
2017     1. In UTF-8 mode, a character class containing characters with values between
2018        127 and 255 was not handled correctly if the compiled pattern was studied.
2019        In fixing this, I have also improved the studying algorithm for such
2020        classes (slightly).
2022     2. Three internal functions had redundant arguments passed to them. Removal
2023        might give a very teeny performance improvement.
2025     3. Documentation bug: the value of the capture_top field in a callout is *one
2026        more than* the number of the hightest numbered captured substring.
2028     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2029        in incorrectly linking with a previously installed version. They now link
2030        explicitly with libpcre.la.
2032     5. configure.in no longer needs to recognize Cygwin specially.
2034     6. A problem in pcre.in for Windows platforms is fixed.
2036     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2037        pcretest, it used to include the size of the study block as part of its
2038        output. Unfortunately, the structure contains a field that has a different
2039        size on different hardware architectures. This meant that the tests that
2040        showed this size failed. As the block is currently always of a fixed size,
2041        this information isn't actually particularly useful in pcretest output, so
2042        I have just removed it.
2044     8. Three pre-processor statements accidentally did not start in column 1.
2045        Sadly, there are *still* compilers around that complain, even though
2046        standard C has not required this for well over a decade. Sigh.
2048     9. In pcretest, the code for checking callouts passed small integers in the
2049        callout_data field, which is a void * field. However, some picky compilers
2050        complained about the casts involved for this on 64-bit systems. Now
2051        pcretest passes the address of the small integer instead, which should get
2052        rid of the warnings.
2054    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2055        both compile and run time, and gives an error if an invalid UTF-8 sequence
2056        is found. There is a option for disabling this check in cases where the
2057        string is known to be correct and/or the maximum performance is wanted.
2059    11. In response to a bug report, I changed one line in Makefile.in from
2061            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2062        to
2063            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2065        to look similar to other lines, but I have no way of telling whether this
2066        is the right thing to do, as I do not use Windows. No doubt I'll get told
2067        if it's wrong...
2070    Version 4.3 21-May-03
2071    ---------------------
2073    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2074       Makefile.
2076    2. Some refactoring to improve the quality of the code:
2078       (i)   The utf8_table... variables are now declared "const".
2080       (ii)  The code for \cx, which used the "case flipping" table to upper case
2081             lower case letters, now just substracts 32. This is ASCII-specific,
2082             but the whole concept of \cx is ASCII-specific, so it seems
2083             reasonable.
2085       (iii) PCRE was using its character types table to recognize decimal and
2086             hexadecimal digits in the pattern. This is silly, because it handles
2087             only 0-9, a-f, and A-F, but the character types table is locale-
2088             specific, which means strange things might happen. A private
2089             table is now used for this - though it costs 256 bytes, a table is
2090             much faster than multiple explicit tests. Of course, the standard
2091             character types table is still used for matching digits in subject
2092             strings against \d.
2094       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2095             ending in _t are). So I've renamed it as ESC_tee.
2097    3. The first argument for regexec() in the POSIX wrapper should have been
2098       defined as "const".
2100    4. Changed pcretest to use malloc() for its buffers so that they can be
2101       Electric Fenced for debugging.
2103    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2104       to read one or more bytes before the start of the subject string. Often this
2105       had no effect on PCRE's behaviour, but in some circumstances it could
2106       provoke a segmentation fault.
2108    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2109       to try to read one or more bytes before the start of the subject string.
2111    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2112       UTF-8 support could misbehave in various ways if the subject string
2113       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2114       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2115       back over UTF-8 characters.)
2118    Version 4.2 14-Apr-03
2119    ---------------------
2121    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2123    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2124         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2125         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2126         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2127         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2128           and BUILD_EXEEXT
2129         Note: automatic setting of the BUILD variables is not yet working
2130         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2131           compile-time but not at link-time
2132         [LINK]: use for linking executables only
2133         make different versions for Windows and non-Windows
2134         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2135           libraries
2136         [LINK_FOR_BUILD]: new variable
2137         [OBJEXT]: use throughout
2138         [EXEEXT]: use throughout
2139         <winshared>: new target
2140         <wininstall>: new target
2141         <dftables.o>: use native compiler
2142         <dftables>: use native linker
2143         <install>: handle Windows platform correctly
2144         <clean>: ditto
2145         <check>: ditto
2146         copy DLL to top builddir before testing
2148       As part of these changes, -no-undefined was removed again. This was reported
2149       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2150       in any case.
2152    3. Some tidies to get rid of compiler warnings:
2154       . In the match_data structure, match_limit was an unsigned long int, whereas
2155         match_call_count was an int. I've made them both unsigned long ints.
2157       . In pcretest the fact that a const uschar * doesn't automatically cast to
2158         a void * provoked a warning.
2160       . Turning on some more compiler warnings threw up some "shadow" variables
2161         and a few more missing casts.
2163    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2164       option, a class that contained a single character with a value between 128
2165       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2167    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2168       option, a class that contained several characters, but with at least one
2169       whose value was between 128 and 255 caused PCRE to crash.
2172    Version 4.1 12-Mar-03
2173    ---------------------
2175    1. Compiling with gcc -pedantic found a couple of places where casts were
2176    needed, and a string in dftables.c that was longer than standard compilers are
2177    required to support.
2179    2. Compiling with Sun's compiler found a few more places where the code could
2180    be tidied up in order to avoid warnings.
2182    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2183    first of these names is deprecated in the latest Autoconf in favour of the name
2184    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2185    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2186    analogy I have changed it to CFLAGS_FOR_BUILD.
2188    4. Added -no-undefined to the linking command in the Makefile, because this is
2189    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2190    linking step for the pcreposix library.
2192    5. PCRE was failing to diagnose the case of two named groups with the same
2193    name.
2195    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2196    literal character that is needed in the subject for a match, and scans along to
2197    ensure that it is present before embarking on the full matching process. This
2198    saves time in cases of nested unlimited repeats that are never going to match.
2199    Problem: the scan can take a lot of time if the subject is very long (e.g.
2200    megabytes), thus penalizing straightforward matches. It is now done only if the
2201    amount of subject to be scanned is less than 1000 bytes.
2203    7. A lesser problem with the same optimization is that it was recording the
2204    first character of an anchored pattern as "needed", thus provoking a search
2205    right along the subject, even when the first match of the pattern was going to
2206    fail. The "needed" character is now not set for anchored patterns, unless it
2207    follows something in the pattern that is of non-fixed length. Thus, it still
2208    fulfils its original purpose of finding quick non-matches in cases of nested
2209    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2212    Version 4.0 17-Feb-03
2213    ---------------------
2215    1. If a comment in an extended regex that started immediately after a meta-item
2216    extended to the end of string, PCRE compiled incorrect data. This could lead to
2217    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2219    2. Moved to autoconf 2.53 and libtool 1.4.2.
2221    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2222    the special perltest8 script is no longer needed - all the tests can be run
2223    from a single perltest script.
2225    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2226    by \s. It has now been removed in PCRE. This means it isn't recognized as
2227    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2228    class [:space:] *does* include VT, thereby creating a mess.
2230    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2231    space and tab.
2233    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2234    its new features into the main test script, reducing the number of scripts.
2236    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2237    were backward compatible, and made the (?i) apply to the whole pattern, as if
2238    /i were given. Now it behaves more logically, and applies the option setting
2239    only to what follows. PCRE has been changed to follow suit. However, if it
2240    finds options settings right at the start of the pattern, it extracts them into
2241    the global options, as before. Thus, they show up in the info data.
2243    8. Added support for the \Q...\E escape sequence. Characters in between are
2244    treated as literals. This is slightly different from Perl in that $ and @ are
2245    also handled as literals inside the quotes. In Perl, they will cause variable
2246    interpolation. Note the following examples:
2248        Pattern            PCRE matches      Perl matches
2250        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2251        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2252        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2254    For compatibility with Perl, \Q...\E sequences are recognized inside character
2255    classes as well as outside them.
2257    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2258    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2259    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2260    signed/unsigned warnings.
2262    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2263    option for pcretest, so I've replaced it by a simple function that does just
2264    that job.
2266    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2267    "pcregrep -".
2269    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2270    Java package. This provides some syntactic sugar for simple cases of what my
2271    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2272    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2273    item, you can use this simplified notation. Note that only makes sense with
2274    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2275    greediness, whatever the setting of the PCRE_UNGREEDY option.
2277    13. A change of greediness default within a pattern was not taking effect at
2278    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2279    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2280    was abstracted outside.
2282    14. PCRE now supports the \G assertion. It is true when the current matching
2283    position is at the start point of the match. This differs from \A when the
2284    starting offset is non-zero. Used with the /g option of pcretest (or similar
2285    code), it works in the same way as it does for Perl's /g option. If all
2286    alternatives of a regex begin with \G, the expression is anchored to the start
2287    match position, and the "anchored" flag is set in the compiled expression.
2289    15. Some bugs concerning the handling of certain option changes within patterns
2290    have been fixed. These applied to options other than (?ims). For example,
2291    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2292    been the other way round. Some of this was related to change 7 above.
2294    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2295    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2296    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2297    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2299    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2300    mode. Unlike ".", it always matches newline, whatever the setting of
2301    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2302    assertions. Perl allows it, but it doesn't (in general) work because it can't
2303    calculate the length of the lookbehind. At least, that's the case for Perl
2304    5.8.0 - I've been told they are going to document that it doesn't work in
2305    future.
2307    18. Added an error diagnosis for escapes that PCRE does not support: these are
2308    \L, \l, \N, \P, \p, \U, \u, and \X.
2310    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2311    reading past the end of the pattern in cases such as /[abcd/.
2313    20. PCRE was getting more memory than necessary for patterns with classes that
2314    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2316    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2317    compiling PCRE for use with Virtual Pascal.
2319    22. Small fix to the Makefile to make it work properly if the build is done
2320    outside the source tree.
2322    23. Added a new extension: a condition to go with recursion. If a conditional
2323    subpattern starts with (?(R) the "true" branch is used if recursion has
2324    happened, whereas the "false" branch is used only at the top level.
2326    24. When there was a very long string of literal characters (over 255 bytes
2327    without UTF support, over 250 bytes with UTF support), the computation of how
2328    much memory was required could be incorrect, leading to segfaults or other
2329    strange effects.
2331    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2332    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2333    there was a subsequent back reference to those brackets. This meant that, for
2334    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2335    possible to check for precisely this case. All we can do is abandon the
2336    optimization if .* occurs inside capturing brackets when there are any back
2337    references whatsoever. (See below for a better fix that came later.)
2339    26. The handling of the optimization for finding the first character of a
2340    non-anchored pattern, and for finding a character that is required later in the
2341    match were failing in some cases. This didn't break the matching; it just
2342    failed to optimize when it could. The way this is done has been re-implemented.
2344    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2346    28. Added a new feature that provides some of the functionality that Perl
2347    provides with (?{...}). The facility is termed a "callout". The way it is done
2348    in PCRE is for the caller to provide an optional function, by setting
2349    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2350    global variable. By default it is unset, which disables all calling out. To get
2351    the function called, the regex must include (?C) at appropriate points. This
2352    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2353    This provides a means of identifying different callout points. When PCRE
2354    reaches such a point in the regex, if pcre_callout has been set, the external
2355    function is called. It is provided with data in a structure called
2356    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2357    matching continues; if it returns a non-zero value, the match at the current
2358    point fails. However, backtracking will occur if possible. [This was changed
2359    later and other features added - see item 49 below.]
2361    29. pcretest is upgraded to test the callout functionality. It provides a
2362    callout function that displays information. By default, it shows the start of
2363    the match and the current position in the text. There are some new data escapes
2364    to vary what happens:
2366        \C+         in addition, show current contents of captured substrings
2367        \C-         do not supply a callout function
2368        \C!n        return 1 when callout number n is reached
2369        \C!n!m      return 1 when callout number n is reached for the mth time
2371    30. If pcregrep was called with the -l option and just a single file name, it
2372    output "<stdin>" if a match was found, instead of the file name.
2374    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2375    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2376    pcre_exec(). This saves a malloc/free per call. The default value of
2377    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2378    when configuring.
2380    32. The default maximum size of a compiled pattern is 64K. There have been a
2381    few cases of people hitting this limit. The code now uses macros to handle the
2382    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2383    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2384    configuring. Tests 2 and 5 work only with 2-byte links because they output
2385    debugging information about compiled patterns.
2387    33. Internal code re-arrangements:
2389    (a) Moved the debugging function for printing out a compiled regex into
2390        its own source file (printint.c) and used #include to pull it into
2391        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2392        separate copies.
2394    (b) Defined the list of op-code names for debugging as a macro in
2395        internal.h so that it is next to the definition of the opcodes.
2397    (c) Defined a table of op-code lengths for simpler skipping along compiled
2398        code. This is again a macro in internal.h so that it is next to the
2399        definition of the opcodes.
2401    34. Added support for recursive calls to individual subpatterns, along the
2402    lines of Robin Houston's patch (but implemented somewhat differently).
2404    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2405    allow it to read and process whole directories in Win32. This code was
2406    contributed by Lionel Fourquaux; it has not been tested by me.
2408    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2409    used to name a group. Names consist of alphanumerics and underscores, and must
2410    be unique. Back references use the syntax (?P=name) and recursive calls use
2411    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2412    numbers. The function pcre_fullinfo() can be used after compilation to extract
2413    a name/number map. There are three relevant calls:
2415      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2416      PCRE_INFO_NAMECOUNT            yields the number of entries
2417      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2419    The map is a vector of fixed-size entries. The size of each entry depends on
2420    the length of the longest name used. The first two bytes of each entry are the
2421    group number, most significant byte first. There follows the corresponding
2422    name, zero terminated. The names are in alphabetical order.
2424    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2425    case instead of 255. Making it the same both with and without UTF-8 support
2426    means that the same test output works with both.
2428    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2429    calling malloc() with a zero argument.
2431    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2432    optimization. I've improved things by keeping a bitmap of backreferences with
2433    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2434    fact referenced, the optimization can be applied. It is unlikely that a
2435    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2436    the match to follow \n) will appear inside brackets with a number greater than
2437    31, but if it does, any back reference > 31 suppresses the optimization.
2439    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2440    of disabling numbered capturing parentheses. Any opening parenthesis that is
2441    not followed by ? behaves as if it were followed by ?: but named parentheses
2442    can still be used for capturing (and they will acquire numbers in the usual
2443    way).
2445    41. Redesigned the return codes from the match() function into yes/no/error so
2446    that errors can be passed back from deep inside the nested calls. A malloc
2447    failure while inside a recursive subpattern call now causes the
2448    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2450    42. It is now possible to set a limit on the number of times the match()
2451    function is called in a call to pcre_exec(). This facility makes it possible to
2452    limit the amount of recursion and backtracking, though not in a directly
2453    obvious way, because the match() function is used in a number of different
2454    circumstances. The count starts from zero for each position in the subject
2455    string (for non-anchored patterns). The default limit is, for compatibility, a
2456    large number, namely 10 000 000. You can change this in two ways:
2458    (a) When configuring PCRE before making, you can use --with-match-limit=n
2459        to set a default value for the compiled library.
2461    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2462        a different value is set. See 45 below.
2464    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2466    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2467    of things that can be changed at compile time. The first argument specifies
2468    what is wanted and the second points to where the information is to be placed.
2469    The current list of available information is:
2471      PCRE_CONFIG_UTF8
2473    The output is an integer that is set to one if UTF-8 support is available;
2474    otherwise it is set to zero.
2478    The output is an integer that it set to the value of the code that is used for
2479    newline. It is either LF (10) or CR (13).
2483    The output is an integer that contains the number of bytes used for internal
2484    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2488    The output is an integer that contains the threshold above which the POSIX
2489    interface uses malloc() for output vectors. See item 31 above.
2493    The output is an unsigned integer that contains the default limit of the number
2494    of match() calls in a pcre_exec() execution. See 42 above.
2496    44. pcretest has been upgraded by the addition of the -C option. This causes it
2497    to extract all the available output from the new pcre_config() function, and to
2498    output it. The program then exits immediately.
2500    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2501    order to support additional features. One way would have been to define
2502    pcre_exec2() (for example) with extra arguments, but this would not have been
2503    extensible, and would also have required all calls to the original function to
2504    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2505    is used for passing in "extra" data from pcre_study().
2507    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2508    contains the following fields:
2510      flags         a bitmap indicating which of the following fields are set
2511      study_data    opaque data from pcre_study()
2512      match_limit   a way of specifying a limit on match() calls for a specific
2513                      call to pcre_exec()
2514      callout_data  data for callouts (see 49 below)
2516    The flag bits are also defined in pcre.h, and are
2522    The pcre_study() function now returns one of these new pcre_extra blocks, with
2523    the actual study data pointed to by the study_data field, and the
2524    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2525    before. That is, this change is entirely upwards-compatible and requires no
2526    change to existing code.
2528    If you want to pass in additional data to pcre_exec(), you can either place it
2529    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2530    block.
2532    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2533    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2534    times with different match limits, until it finds the minimum value needed for
2535    pcre_exec() to complete. The value is then output. This can be instructive; for
2536    most simple matches the number is quite small, but for pathological cases it
2537    gets very large very quickly.
2539    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2540    returns the size of the data block pointed to by the study_data field in a
2541    pcre_extra block, that is, the value that was passed as the argument to
2542    pcre_malloc() when PCRE was getting memory in which to place the information
2543    created by pcre_study(). The fourth argument should point to a size_t variable.
2544    pcretest has been extended so that this information is shown after a successful
2545    pcre_study() call when information about the compiled regex is being displayed.
2547    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2548    because what follows is always an absolute path. (Later: it turns out that this
2549    is more than cosmetic for MinGW, because it doesn't like empty path
2550    components.)
2552    49. Some changes have been made to the callout feature (see 28 above):
2554    (i)  A callout function now has three choices for what it returns:
2556           0  =>  success, carry on matching
2557         > 0  =>  failure at this point, but backtrack if possible
2558         < 0  =>  serious error, return this value from pcre_exec()
2560         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2561         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2562         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2563         use by callout functions. It will never be used by PCRE itself.
2565    (ii) The pcre_extra structure (see 45 above) has a void * field called
2566         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2567         pcre_callout_block structure has a field of the same name. The contents of
2568         the field passed in the pcre_extra structure are passed to the callout
2569         function in the corresponding field in the callout block. This makes it
2570         easier to use the same callout-containing regex from multiple threads. For
2571         testing, the pcretest program has a new data escape
2573           \C*n        pass the number n (may be negative) as callout_data
2575         If the callout function in pcretest receives a non-zero value as
2576         callout_data, it returns that value.
2578    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2579    there were some redundant $(CFLAGS) in commands that are now specified as
2580    $(LINK), which already includes $(CFLAGS).
2582    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2583    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2584    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2585    one-byte characters throughout. Note that case-insensitive matching applies
2586    only to characters whose values are less than 256. PCRE doesn't support the
2587    notion of cases for higher-valued characters.
2589    (i)   A character class whose characters are all within 0-255 is handled as
2590          a bit map, and the map is inverted for negative classes. Previously, a
2591          character > 255 always failed to match such a class; however it should
2592          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2594    (ii)  A negated character class with a single character < 255 is coded as
2595          "not this character" (OP_NOT). This wasn't working properly when the test
2596          character was multibyte, either singly or repeated.
2598    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2599          mode, for example: \x{100}{2,3}.
2601    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2602          singly or repeated) now correctly test multibyte characters. However,
2603          PCRE doesn't recognize any characters with values greater than 255 as
2604          digits, spaces, or word characters. Such characters always match \D, \S,
2605          and \W, and never match \d, \s, or \w.
2607    (v)   Classes may now contain characters and character ranges with values
2608          greater than 255. For example: [ab\x{100}-\x{400}].
2610    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2611          PCRE in UTF-8 mode.
2613    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2614    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2615    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2616    value.)
2618    53. The single man page has become too large. I have therefore split it up into
2619    a number of separate man pages. These also give rise to individual HTML pages;
2620    these are now put in a separate directory, and there is an index.html page that
2621    lists them all. Some hyperlinking between the pages has been installed.
2623    54. Added convenience functions for handling named capturing parentheses.
2625    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2626    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2627    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2628    are faulted.
2630    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2631    calling configure. These values are used when compiling the dftables.c program
2632    which is run to generate the source of the default character tables. They
2633    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2634    you will need to set these values.
2636    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2639    Version 3.9 02-Jan-02
2640    ---------------------
2642    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2644    2. If --disable-static was given, the building process failed when trying to
2645    build pcretest and pcregrep. (For some reason it was using libtool to compile
2646    them, which is not right, as they aren't part of the library.)
2649    Version 3.8 18-Dec-01
2650    ---------------------
2652    1. The experimental UTF-8 code was completely screwed up. It was packing the
2653    bytes in the wrong order. How dumb can you get?
2656    Version 3.7 29-Oct-01
2657    ---------------------
2659    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2660    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2661    this didn't happen under Solaris 8, where I normally test things.
2663    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2664    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2665    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2666    this fix an hour or so after the initial 3.7 release.)
2669    Version 3.6 23-Oct-01
2670    ---------------------
2672    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2673    offsets passed as NULL with zero offset count.
2675    2. The config.guess and config.sub files had not been updated when I moved to
2676    the latest autoconf.
2679    Version 3.5 15-Aug-01
2680    ---------------------
2682    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2683    had been forgotten.
2685    2. By using declared but undefined structures, we can avoid using "void"
2686    definitions in pcre.h while keeping the internal definitions of the structures
2687    private.
2689    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2690    user point of view, this means that both static and shared libraries are built
2691    by default, but this can be individually controlled. More of the work of
2692    handling this static/shared cases is now inside libtool instead of PCRE's make
2693    file.
2695    4. The pcretest utility is now installed along with pcregrep because it is
2696    useful for users (to test regexs) and by doing this, it automatically gets
2697    relinked by libtool. The documentation has been turned into a man page, so
2698    there are now .1, .txt, and .html versions in /doc.
2700    5. Upgrades to pcregrep:
2701       (i)   Added long-form option names like gnu grep.
2702       (ii)  Added --help to list all options with an explanatory phrase.
2703       (iii) Added -r, --recursive to recurse into sub-directories.
2704       (iv)  Added -f, --file to read patterns from a file.
2706    6. pcre_exec() was referring to its "code" argument before testing that
2707    argument for NULL (and giving an error if it was NULL).
2709    7. Upgraded Makefile.in to allow for compiling in a different directory from
2710    the source directory.
2712    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2713    options bits, the pointer it was passed was to an int instead of to an unsigned
2714    long int. This mattered only on 64-bit systems.
2716    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2717    generated) instead of pcre.in, which it its source. Also made the same change
2718    in several of the .c files.
2720    10. A new release of gcc defines printf() as a macro, which broke pcretest
2721    because it had an ifdef in the middle of a string argument for printf(). Fixed
2722    by using separate calls to printf().
2724    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2725    script, to force use of CR or LF instead of \n in the source. On non-Unix
2726    systems, the value can be set in config.h.
2728    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2729    absolute limit. Changed the text of the error message to make this clear, and
2730    likewise updated the man page.
2732    13. The limit of 99 on the number of capturing subpatterns has been removed.
2733    The new limit is 65535, which I hope will not be a "real" limit.
2736    Version 3.4 22-Aug-00
2737    ---------------------
2739    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2741    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2744    Version 3.3 01-Aug-00
2745    ---------------------
2747    1. If an octal character was given, but the value was greater than \377, it
2748    was not getting masked to the least significant bits, as documented. This could
2749    lead to crashes in some systems.
2751    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2752    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2754    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2755    These just pass their arguments on to (pcre_free)(), but they are provided
2756    because some uses of PCRE bind it to non-C systems that can call its functions,
2757    but cannot call free() or pcre_free() directly.
2759    4. Add "make test" as a synonym for "make check". Corrected some comments in
2760    the Makefile.
2762    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2763    Makefile.
2765    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2766    command called pgrep for grepping around the active processes.
2768    7. Added the beginnings of support for UTF-8 character strings.
2770    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2771    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2772    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2773    out for the ar command.)
2776    Version 3.2 12-May-00
2777    ---------------------
2779    This is purely a bug fixing release.
2781    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2782    of ZA. This was just one example of several cases that could provoke this bug,
2783    which was introduced by change 9 of version 2.00. The code for breaking
2784    infinite loops after an iteration that matches an empty string was't working
2785    correctly.
2787    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2788    when matched against abbab (for example). After matching an empty string, it
2789    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2790    caused it to match further down the string than it should.
2792    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2793    was there because it doesn't seem to be needed, and it causes trouble on some
2794    systems, as it is not a Standard C header. It has been removed.
2796    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2797    were reported on the Macintosh. The changes were from
2799      while ((c = *(++ptr)) != 0 && c != '\n');
2800    to
2801      while ((c = *(++ptr)) != 0 && c != '\n') ;
2803    Totally extraordinary, but if that's what it takes...
2805    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2806    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2807    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2808    assumes the way PCRE uses memmove() (always moving upwards).
2810    6. PCRE is being used in one environment where strchr() is not available. There
2811    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2812    faster code anyway.
2815    Version 3.1 09-Feb-00
2816    ---------------------
2818    The only change in this release is the fixing of some bugs in Makefile.in for
2819    the "install" target:
2821    (1) It was failing to install pcreposix.h.
2823    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2826    Version 3.0 01-Feb-00
2827    ---------------------
2829    1. Add support for the /+ modifier to perltest (to output $` like it does in
2830    pcretest).
2832    2. Add support for the /g modifier to perltest.
2834    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2835    matches null strings.
2837    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2838    pattern. Perl treats empty patterns specially - it reuses the most recent
2839    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2840    effect.
2842    5. The POSIX interface was broken in that it was just handing over the POSIX
2843    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2844    required a bigger vector, with some working space on the end. This means that
2845    the POSIX wrapper now has to get and free some memory, and copy the results.
2847    6. Added some simple autoconf support, placing the test data and the
2848    documentation in separate directories, re-organizing some of the
2849    information files, and making it build pcre-config (a GNU standard). Also added
2850    libtool support for building PCRE as a shared library, which is now the
2851    default.
2853    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2854    09 are not valid octal constants. Single digits will be used for minor values
2855    less than 10.
2857    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2858    existing programs that set these in the POSIX interface can use PCRE without
2859    modification.
2861    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2862    return all that pcre_info() returns, plus additional data. The pcre_info()
2863    function is retained for compatibility, but is considered to be obsolete.
2865    10. Added experimental recursion feature (?R) to handle one common case that
2866    Perl 5.6 will be able to do with (?p{...}).
2868    11. Added support for POSIX character classes like [:alpha:], which Perl is
2869    adopting.
2872    Version 2.08 31-Aug-99
2873    ----------------------
2875    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2876    trying to match at the startoffset position, but instead was moving forward to
2877    the next newline as if a previous match had failed.
2879    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2880    and could get into a loop if a null string was matched other than at the start
2881    of the subject.
2883    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2884    be distinguished at compile time, and for completeness also added PCRE_DATE.
2886    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2887    in GnuWin32 environments.
2890    Version 2.07 29-Jul-99
2891    ----------------------
2893    1. The documentation is now supplied in plain text form and HTML as well as in
2894    the form of man page sources.
2896    2. C++ compilers don't like assigning (void *) values to other pointer types.
2897    In particular this affects malloc(). Although there is no problem in Standard
2898    C, I've put in casts to keep C++ compilers happy.
2900    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2901    should be (const char *).
2903    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2904    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2905    However, I haven't made this a standard facility. The documentation doesn't
2906    mention it, and the Makefile doesn't support it.
2908    5. The Makefile now contains an "install" target, with editable destinations at
2909    the top of the file. The pcretest program is not installed.
2911    6. pgrep -V now gives the PCRE version number and date.
2913    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2914    causing the entire string to be ignored, instead of just the last character.
2916    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2917    non-matching string, it can take a very, very long time, even for strings of
2918    quite modest length, because of the nested recursion. PCRE now does better in
2919    some of these cases. It does this by remembering the last required literal
2920    character in the pattern, and pre-searching the subject to ensure it is present
2921    before running the real match. In other words, it applies a heuristic to detect
2922    some types of certain failure quickly, and in the above example, if presented
2923    with a string that has no trailing " it gives "no match" very quickly.
2925    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2926    other alternatives are tried instead.
2929  Version 2.06 09-Jun-99  Version 2.06 09-Jun-99
2930  ----------------------  ----------------------

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