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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.5 12-Nov-07  Version 8.32
5    ------------
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
13    3.  Single character iterator optimizations in the JIT compiler.
15    4.  Improved JIT compiler optimizations for character ranges.
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
26    Version 8.31 06-July-2012
27    -------------------------
29    1.  Fixing a wrong JIT test case and some compiler warnings.
31    2.  Removed a bashism from the RunTest script.
33    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
34        to unsigned type, result still unsigned" that was given by an MS compiler
35        on encountering the code "-sizeof(xxx)".
37    4.  Partial matching support is added to the JIT compiler.
39    5.  Fixed several bugs concerned with partial matching of items that consist
40        of more than one character:
42        (a) /^(..)\1/ did not partially match "aba" because checking references was
43            done on an "all or nothing" basis. This also applied to repeated
44            references.
46        (b) \R did not give a hard partial match if \r was found at the end of the
47            subject.
49        (c) \X did not give a hard partial match after matching one or more
50            characters at the end of the subject.
52        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
53            a partial match for the string "\r".
55        (e) When newline was set to CRLF, the metacharacter "." did not recognize
56            a partial match for a CR character at the end of the subject string.
58    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
59        running pcretest, the text "(JIT)" added to the output whenever JIT is
60        actually used to run the match.
62    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
63        or /S+[+] with a digit between 1 and 7.
65    8.  OP_NOT now supports any UTF character not just single-byte ones.
67    9.  (*MARK) control verb is now supported by the JIT compiler.
69    10. The command "./RunTest list" lists the available tests without actually
70        running any of them. (Because I keep forgetting what they all are.)
74    12. Applied a (slightly modified) user-supplied patch that improves performance
75        when the heap is used for recursion (compiled with --disable-stack-for-
76        recursion). Instead of malloc and free for each heap frame each time a
77        logical recursion happens, frames are retained on a chain and re-used where
78        possible. This sometimes gives as much as 30% improvement.
80    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
81        call.
83    14. As documented, (*COMMIT) is now confined to within a positive assertion.
85    15. It is now possible to link pcretest with libedit as an alternative to
86        libreadline.
88    16. (*COMMIT) control verb is now supported by the JIT compiler.
90    17. The Unicode data tables have been updated to Unicode 6.1.0.
92    18. Added --file-list option to pcregrep.
94    19. Added binary file support to pcregrep, including the -a, --binary-files,
95        -I, and --text options.
97    20. The madvise function is renamed for posix_madvise for QNX compatibility
98        reasons. Fixed by Giuseppe D'Angelo.
100    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
102    22. Changed the option for creating symbolic links for 16-bit man pages from
103        -s to -sf so that re-installing does not cause issues.
105    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
107    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
108        matches in certain environments (the workspace was not being correctly
109        retained). Also added to pcre_dfa_exec() a simple plausibility check on
110        some of the workspace data at the beginning of a restart.
112    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
113        was not doing so when it should - probably a typo introduced by SVN 528
114        (change 8.10/14).
116    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
117        \w+ when the character tables indicated that \x{c4} was a word character.
118        There were several related cases, all because the tests for doing a table
119        lookup were testing for characters less than 127 instead of 255.
121    27. If a pattern contains capturing parentheses that are not used in a match,
122        their slots in the ovector are set to -1. For those that are higher than
123        any matched groups, this happens at the end of processing. In the case when
124        there were back references that the ovector was too small to contain
125        (causing temporary malloc'd memory to be used during matching), and the
126        highest capturing number was not used, memory off the end of the ovector
127        was incorrectly being set to -1. (It was using the size of the temporary
128        memory instead of the true size.)
130    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
131        ovector size, it uses memory at the end of the block that it has got.
133    29. Check for an overlong MARK name and give an error at compile time. The
134        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
136    30. JIT compiler update.
138    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
139        Rill for the patch.
141    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
143    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
145    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
146        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
147        was enabled.
149    35. Improve JIT code generation for greedy plus quantifier.
151    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
152        1 to "aa" instead of to an empty string. The bug affected repeated groups
153        that could potentially match an empty string.
155    37. Optimizing single character iterators in JIT.
157    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
158        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
159        codepoints that are too big for the mode are faulted, and in a UTF mode,
160        disallowed codepoints are also faulted.
162    39. If PCRE was compiled with UTF support, in three places in the DFA
163        matcher there was code that should only have been obeyed in UTF mode, but
164        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
165        processing when bytes with values greater than 127 were present. In 16-bit
166        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
167        both cases the values are those that cannot be the first data item in a UTF
168        character. The three items that might have provoked this were recursions,
169        possessively repeated groups, and atomic groups.
171    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
172        and pcregrep, because some OS require shared objects to be explicitly
173        passed to ld, causing the link step to fail if they are not.
175    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
176        mode, patterns that started with \h* or \R* might be incorrectly matched.
179    Version 8.30 04-February-2012
180    -----------------------------
182    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
183        name is defined in ctype.h.
185    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
186        only in quite long subpatterns.
188    3.  Removed the function pcre_info(), which has been obsolete and deprecated
189        since it was replaced by pcre_fullinfo() in February 2000.
191    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
192        match a (*MARK), and the match failed at the start of the subject, a
193        reference to memory before the start of the subject could occur. This bug
194        was introduced by fix 17 of release 8.21.
196    5.  A reference to an unset group with zero minimum repetition was giving
197        totally wrong answers (in non-JavaScript-compatibility mode). For example,
198        /(another)?(\1?)test/ matched against "hello world test". This bug was
199        introduced in release 8.13.
201    6.  Add support for 16-bit character strings (a large amount of work involving
202        many changes and refactorings).
204    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
205        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
206        from a file.
208    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
209        rounding is not applied in this particular case).
211    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
212        if they appear, or are escaped, in patterns.
214    10. Get rid of a number of -Wunused-but-set-variable warnings.
216    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
217        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
218        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
219        also returns the mark "x". This bug applied to capturing parentheses,
220        non-capturing parentheses, and atomic parentheses. It also applied to some
221        assertions.
223    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
224        information out of configure.ac instead of relying on pcre.h.generic, which
225        is not stored in the repository.
227    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
228        -lreadline.
230    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
232    15. Applied Graycode's patch to put the top-level frame on the stack rather
233        than the heap when not using the stack for recursion. This gives a
234        performance improvement in many cases when recursion is not deep.
236    16. Experimental code added to "pcretest -C" to output the stack frame size.
239    Version 8.21 12-Dec-2011
240    ------------------------
242    1.  Updating the JIT compiler.
244    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
245        are added as well.
247    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
248        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
249        calling _pcre_jit_exec. Some extra comments are added.
251    4.  (*MARK) settings inside atomic groups that do not contain any capturing
252        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
253        was introduced by change 18 for 8.20.
255    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
256        ECMA-262 standard.
258    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
259        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
260        This bug was probably introduced by change 9 of 8.13.
262    7.  While fixing 6 above, I noticed that a number of other items were being
263        incorrectly rejected as "not fixed length". This arose partly because newer
264        opcodes had not been added to the fixed-length checking code. I have (a)
265        corrected the bug and added tests for these items, and (b) arranged for an
266        error to occur if an unknown opcode is encountered while checking for fixed
267        length instead of just assuming "not fixed length". The items that were
268        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
269        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
270        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
272    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
273        being incorrectly compiled and would have given unpredicatble results.
275    9.  A possessively repeated subpattern with minimum repeat count greater than
276        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
277        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
278        the first (A) could occur when it should not.
280    10. Add a cast and remove a redundant test from the code.
282    11. JIT should use pcre_malloc/pcre_free for allocation.
284    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
285        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
286        is anything other than /usr, -L is still shown).
288    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
290    14. Perl does not support \N without a following name in a [] class; PCRE now
291        also gives an error.
293    15. If a forward reference was repeated with an upper limit of around 2000,
294        it caused the error "internal error: overran compiling workspace". The
295        maximum number of forward references (including repeats) was limited by the
296        internal workspace, and dependent on the LINK_SIZE. The code has been
297        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
298        the default depends on LINK_SIZE. There is a new upper limit (for safety)
299        of around 200,000 forward references. While doing this, I also speeded up
300        the filling in of repeated forward references.
302    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
303        incorrectly expecting the subject to contain another "a" after the start.
305    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
306        in the match, the SKIP should be ignored. This was not happening; instead
307        the SKIP was being treated as NOMATCH. For patterns such as
308        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
309        tested.
311    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
312        now much more compatible with Perl, in particular in cases where the result
313        is a non-match for a non-anchored pattern. For example, if
314        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
315        "m", where previously it did not return a name. A side effect of this
316        change is that for partial matches, the last encountered mark name is
317        returned, as for non matches. A number of tests that were previously not
318        Perl-compatible have been moved into the Perl-compatible test files. The
319        refactoring has had the pleasing side effect of removing one argument from
320        the match() function, thus reducing its stack requirements.
322    19. If the /S+ option was used in pcretest to study a pattern using JIT,
323        subsequent uses of /S (without +) incorrectly behaved like /S+.
325    21. Retrieve executable code size support for the JIT compiler and fixing
326        some warnings.
328    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
329        not work when the shorter character appeared right at the end of the
330        subject string.
332    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
333        systems.
335    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
336        output it when the /M option is used in pcretest.
338    25. The CheckMan script was not being included in the distribution. Also, added
339        an explicit "perl" to run Perl scripts from the PrepareRelease script
340        because this is reportedly needed in Windows.
342    26. If study data was being save in a file and studying had not found a set of
343        "starts with" bytes for the pattern, the data written to the file (though
344        never used) was taken from uninitialized memory and so caused valgrind to
345        complain.
347    27. Updated RunTest.bat as provided by Sheri Pierce.
349    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
351    29. Computation of memory usage for the table of capturing group names was
352        giving an unnecessarily large value.
355    Version 8.20 21-Oct-2011
356    ------------------------
358    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
359        a POSIX class. After further experiments with Perl, which convinced me that
360        Perl has bugs and confusions, a closing square bracket is no longer allowed
361        in a POSIX name. This bug also affected patterns with classes that started
362        with full stops.
364    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
365        captured substring, but while checking the failing first alternative,
366        substring 1 is temporarily captured. If the output vector supplied to
367        pcre_exec() was not big enough for this capture, the yield of the function
368        was still zero ("insufficient space for captured substrings"). This cannot
369        be totally fixed without adding another stack variable, which seems a lot
370        of expense for a edge case. However, I have improved the situation in cases
371        such as /(a)(b)x|abc/ matched against "abc", where the return code
372        indicates that fewer than the maximum number of slots in the ovector have
373        been set.
375    3.  Related to (2) above: when there are more back references in a pattern than
376        slots in the output vector, pcre_exec() uses temporary memory during
377        matching, and copies in the captures as far as possible afterwards. It was
378        using the entire output vector, but this conflicts with the specification
379        that only 2/3 is used for passing back captured substrings. Now it uses
380        only the first 2/3, for compatibility. This is, of course, another edge
381        case.
383    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
384        main code base, and can be used by building with --enable-jit. When this is
385        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
386        runtime --no-jit option is given.
388    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
389        ovector, the return from the function was zero, implying that there were
390        other matches that did not fit. The correct "exactly full" value is now
391        returned.
393    6.  If a subpattern that was called recursively or as a subroutine contained
394        (*PRUNE) or any other control that caused it to give a non-standard return,
395        invalid errors such as "Error -26 (nested recursion at the same subject
396        position)" or even infinite loops could occur.
398    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
399        computing the minimum length on reaching *ACCEPT, and so ended up with the
400        wrong value of 1 rather than 0. Further investigation indicates that
401        computing a minimum subject length in the presence of *ACCEPT is difficult
402        (think back references, subroutine calls), and so I have changed the code
403        so that no minimum is registered for a pattern that contains *ACCEPT.
405    8.  If (*THEN) was present in the first (true) branch of a conditional group,
406        it was not handled as intended. [But see 16 below.]
408    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
409        Sheri Pierce.
411    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
412        the first byte in a match must be "a".
414    11. Change 17 for 8.13 increased the recursion depth for patterns like
415        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
416        pattern contains any instances of (*THEN). If it does not, the old
417        optimizations are restored. It would be nice to do this on a per-group
418        basis, but at the moment that is not feasible.
420    12. In some environments, the output of pcretest -C is CRLF terminated. This
421        broke RunTest's code that checks for the link size. A single white space
422        character after the value is now allowed for.
424    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
425        For "fr", it uses the Windows-specific input and output files.
427    14. If (*THEN) appeared in a group that was called recursively or as a
428        subroutine, it did not work as intended. [But see next item.]
430    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
431        pattern fragments (but not containing any | characters). If A and B are
432        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
433        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
434        D. In other words, Perl considers parentheses that do not contain any |
435        characters to be part of a surrounding alternative, whereas PCRE was
436        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
437        differently. PCRE now behaves in the same way as Perl, except in the case
438        of subroutine/recursion calls such as (?1) which have in any case always
439        been different (but PCRE had them first :-).
441    16. Related to 15 above: Perl does not treat the | in a conditional group as
442        creating alternatives. Such a group is treated in the same way as an
443        ordinary group without any | characters when processing (*THEN). PCRE has
444        been changed to match Perl's behaviour.
446    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
447        RunGrepTest script failed.
449    18. Change 22 for version 13 caused atomic groups to use more stack. This is
450        inevitable for groups that contain captures, but it can lead to a lot of
451        stack use in large patterns. The old behaviour has been restored for atomic
452        groups that do not contain any capturing parentheses.
454    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
455        suppress the check for a minimum subject length at run time. (If it was
456        given to pcre_exec() or pcre_dfa_exec() it did work.)
458    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
459        fail to work when decoding hex characters in data strings in EBCDIC
460        environments.
462    21. It appears that in at least one Mac OS environment, the isxdigit() function
463        is implemented as a macro that evaluates to its argument more than once,
464        contravening the C 90 Standard (I haven't checked a later standard). There
465        was an instance in pcretest which caused it to go wrong when processing
466        \x{...} escapes in subject strings. The has been rewritten to avoid using
467        things like p++ in the argument of isxdigit().
470    Version 8.13 16-Aug-2011
471    ------------------------
473    1.  The Unicode data tables have been updated to Unicode 6.0.0.
475    2.  Two minor typos in pcre_internal.h have been fixed.
477    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
478        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
479        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
481    4.  There were a number of related bugs in the code for matching backrefences
482        caselessly in UTF-8 mode when codes for the characters concerned were
483        different numbers of bytes. For example, U+023A and U+2C65 are an upper
484        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
485        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
486        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
487        2-byte code at the end of the subject (it thought there wasn't enough data
488        left).
490    5.  Comprehensive information about what went wrong is now returned by
491        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
492        as the output vector has at least 2 elements. The offset of the start of
493        the failing character and a reason code are placed in the vector.
495    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
496        now returned is for the first byte of the failing character, instead of the
497        last byte inspected. This is an incompatible change, but I hope it is small
498        enough not to be a problem. It makes the returned offset consistent with
499        pcre_exec() and pcre_dfa_exec().
501    7.  pcretest now gives a text phrase as well as the error number when
502        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
503        failure, the offset and reason code are output.
505    8.  When \R was used with a maximizing quantifier it failed to skip backwards
506        over a \r\n pair if the subsequent match failed. Instead, it just skipped
507        back over a single character (\n). This seems wrong (because it treated the
508        two characters as a single entity when going forwards), conflicts with the
509        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
510        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
511        has been changed.
513    9.  Some internal refactoring has changed the processing so that the handling
514        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
515        time (the PCRE_DOTALL option was changed this way some time ago: version
516        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
517        which was always a bit of a fudge. It also means that there is one less
518        argument for the match() function, which reduces its stack requirements
519        slightly. This change also fixes an incompatibility with Perl: the pattern
520        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
522    10. More internal refactoring has drastically reduced the number of recursive
523        calls to match() for possessively repeated groups such as (abc)++ when
524        using pcre_exec().
526    11. While implementing 10, a number of bugs in the handling of groups were
527        discovered and fixed:
529        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
530        (a|)*(?1) gave a compile-time internal error.
531        ((a|)+)+  did not notice that the outer group could match an empty string.
532        (^a|^)+   was not marked as anchored.
533        (.*a|.*)+ was not marked as matching at start or after a newline.
535    12. Yet more internal refactoring has removed another argument from the match()
536        function. Special calls to this function are now indicated by setting a
537        value in a variable in the "match data" data block.
539    13. Be more explicit in pcre_study() instead of relying on "default" for
540        opcodes that mean there is no starting character; this means that when new
541        ones are added and accidentally left out of pcre_study(), testing should
542        pick them up.
544    14. The -s option of pcretest has been documented for ages as being an old
545        synonym of -m (show memory usage). I have changed it to mean "force study
546        for every regex", that is, assume /S for every regex. This is similar to -i
547        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
548        using it. It makes it easier to run collections of tests with and without
549        study enabled, and thereby test pcre_study() more easily. All the standard
550        tests are now run with and without -s (but some patterns can be marked as
551        "never study" - see 20 below).
553    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
554        restoration of the capturing data to the outer values was not happening
555        correctly.
557    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
558        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
559        pattern had matched an empty string, and so incorrectly returned a no
560        match.
562    17. There was optimizing code for the last branch of non-capturing parentheses,
563        and also for the obeyed branch of a conditional subexpression, which used
564        tail recursion to cut down on stack usage. Unfortunately, now that there is
565        the possibility of (*THEN) occurring in these branches, tail recursion is
566        no longer possible because the return has to be checked for (*THEN). These
567        two optimizations have therefore been removed. [But see 8.20/11 above.]
569    18. If a pattern containing \R was studied, it was assumed that \R always
570        matched two bytes, thus causing the minimum subject length to be
571        incorrectly computed because \R can also match just one byte.
573    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
574        was incorrectly computed.
576    20. If /S is present twice on a test pattern in pcretest input, it now
577        *disables* studying, thereby overriding the use of -s on the command line
578        (see 14 above). This is necessary for one or two tests to keep the output
579        identical in both cases.
581    21. When (*ACCEPT) was used in an assertion that matched an empty string and
582        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
584    22. When an atomic group that contained a capturing parenthesis was
585        successfully matched, but the branch in which it appeared failed, the
586        capturing was not being forgotten if a higher numbered group was later
587        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
588        group 1 to "a", when in fact it should be unset. This applied to multi-
589        branched capturing and non-capturing groups, repeated or not, and also to
590        positive assertions (capturing in negative assertions does not happen
591        in PCRE) and also to nested atomic groups.
593    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
594        subject after a captured substring, to make it easier to tell which of a
595        number of identical substrings has been captured.
597    24. The way atomic groups are processed by pcre_exec() has been changed so that
598        if they are repeated, backtracking one repetition now resets captured
599        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
600        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
601        "aaa". Previously, it would have been "a". As part of this code
602        refactoring, the way recursive calls are handled has also been changed.
604    25. If an assertion condition captured any substrings, they were not passed
605        back unless some other capturing happened later. For example, if
606        (?(?=(a))a) was matched against "a", no capturing was returned.
608    26. When studying a pattern that contained subroutine calls or assertions,
609        the code for finding the minimum length of a possible match was handling
610        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
611        group 1 called group 2 while simultaneously a separate group 2 called group
612        1). A stack overflow occurred in this case. I have fixed this by limiting
613        the recursion depth to 10.
615    27. Updated RunTest.bat in the distribution to the version supplied by Tom
616        Fortmann. This supports explicit test numbers on the command line, and has
617        argument validation and error reporting.
619    28. An instance of \X with an unlimited repeat could fail if at any point the
620        first character it looked at was a mark character.
622    29. Some minor code refactoring concerning Unicode properties and scripts
623        should reduce the stack requirement of match() slightly.
625    30. Added the '=' option to pcretest to check the setting of unused capturing
626        slots at the end of the pattern, which are documented as being -1, but are
627        not included in the return count.
629    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
630        compiled something random. Now it gives a compile-time error (as does
631        Perl).
633    32. A *MARK encountered during the processing of a positive assertion is now
634        recorded and passed back (compatible with Perl).
636    33. If --only-matching or --colour was set on a pcregrep call whose pattern
637        had alternative anchored branches, the search for a second match in a line
638        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
639        matched the line "0102" twice. The same bug affected patterns that started
640        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
641        twice.
643    34. Previously, PCRE did not allow quantification of assertions. However, Perl
644        does, and because of capturing effects, quantifying parenthesized
645        assertions may at times be useful. Quantifiers are now allowed for
646        parenthesized assertions.
648    35. A minor code tidy in pcre_compile() when checking options for \R usage.
650    36. \g was being checked for fancy things in a character class, when it should
651        just be a literal "g".
653    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
654        appearance of a nested POSIX class supersedes an apparent external class.
655        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
656        unescaped square brackets may also appear as part of class names. For
657        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
658        more like Perl. (But see 8.20/1 above.)
660    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
661        was because it thought it was \N{name}, which is not supported).
663    39. Add minix to OS list not supporting the -S option in pcretest.
665    40. PCRE tries to detect cases of infinite recursion at compile time, but it
666        cannot analyze patterns in sufficient detail to catch mutual recursions
667        such as ((?1))((?2)). There is now a runtime test that gives an error if a
668        subgroup is called recursively as a subpattern for a second time at the
669        same position in the subject string. In previous releases this might have
670        been caught by the recursion limit, or it might have run out of stack.
672    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
673        happen only once. PCRE was, however incorrectly giving a compile time error
674        "recursive call could loop indefinitely" because it cannot analyze the
675        pattern in sufficient detail. The compile time test no longer happens when
676        PCRE is compiling a conditional subpattern, but actual runaway loops are
677        now caught at runtime (see 40 above).
679    42. It seems that Perl allows any characters other than a closing parenthesis
680        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
681        has been changed to be the same.
683    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
684        as not to get warnings when autogen.sh is called. Also changed
685        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
687    44. To help people who use pcregrep to scan files containing exceedingly long
688        lines, the following changes have been made:
690        (a) The default value of the buffer size parameter has been increased from
691            8K to 20K. (The actual buffer used is three times this size.)
693        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
694            PCRE is built.
696        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
697            to be set at run time.
699        (d) Numerical values in pcregrep options can be followed by K or M, for
700            example --buffer-size=50K.
702        (e) If a line being scanned overflows pcregrep's buffer, an error is now
703            given and the return code is set to 2.
705    45. Add a pointer to the latest mark to the callout data block.
707    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
708        partial match of an empty string instead of no match. This was specific to
709        the use of ".".
711    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
712        complete match instead of a partial match. This bug was dependent on both
713        the PCRE_UTF8 and PCRE_DOTALL options being set.
715    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
716        starting byte set, because \b was not being ignored.
719    Version 8.12 15-Jan-2011
720    ------------------------
722    1.  Fixed some typos in the markup of the man pages, and wrote a script that
723        checks for such things as part of the documentation building process.
725    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
726        --match-limit and --recursion-limit options (added for 8.11). In
727        particular, this made one of the standard tests fail. (The integer value
728        went into the wrong half of a long int.)
730    3.  If the --colour option was given to pcregrep with -v (invert match), it
731        did strange things, either producing crazy output, or crashing. It should,
732        of course, ignore a request for colour when reporting lines that do not
733        match.
735    4.  Another pcregrep bug caused similar problems if --colour was specified with
736        -M (multiline) and the pattern match finished with a line ending.
738    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
739        matched in multiline mode, the following line was shown as part of the
740        match. This seems wrong, so I have changed it.
742    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
743        the check for further matches in the same line (so they could be coloured)
744        to overrun the end of the current line. If another match was found, it was
745        incorrectly shown (and then shown again when found in the next line).
747    7.  If pcregrep was compiled under Windows, there was a reference to the
748        function pcregrep_exit() before it was defined. I am assuming this was
749        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
750        reported by a user. I've moved the definition above the reference.
753    Version 8.11 10-Dec-2010
754    ------------------------
756    1.  (*THEN) was not working properly if there were untried alternatives prior
757        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
758        backtracked to try for "b" instead of moving to the next alternative branch
759        at the same level (in this case, to look for "c"). The Perl documentation
760        is clear that when (*THEN) is backtracked onto, it goes to the "next
761        alternative in the innermost enclosing group".
763    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
764        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
765        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
766        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
767        (*THEN).
769    3.  If \s appeared in a character class, it removed the VT character from
770        the class, even if it had been included by some previous item, for example
771        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
772        of \s, but is part of the POSIX "space" class.)
774    4.  A partial match never returns an empty string (because you can always
775        match an empty string at the end of the subject); however the checking for
776        an empty string was starting at the "start of match" point. This has been
777        changed to the "earliest inspected character" point, because the returned
778        data for a partial match starts at this character. This means that, for
779        example, /(?<=abc)def/ gives a partial match for the subject "abc"
780        (previously it gave "no match").
782    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
783        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
784        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
785        has an implication that the given string is incomplete (because a partial
786        match is preferred over a full match). For this reason, these items now
787        give a partial match in this situation. [Aside: previously, the one case
788        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
789        match rather than a full match, which was wrong by the old rules, but is
790        now correct.]
792    6.  There was a bug in the handling of #-introduced comments, recognized when
793        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
794        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
795        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
796        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
797        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
798        places in pcre_compile().
800    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
801        comments when looking ahead for named forward references to subpatterns,
802        the only newline sequence it recognized was NL. It now handles newlines
803        according to the set newline convention.
805    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
806        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
807        cater for a lack of strerror(). These oversights have been fixed.
809    9.  Added --match-limit and --recursion-limit to pcregrep.
811    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
813    11. When the -o option was used, pcregrep was setting a return code of 1, even
814        when matches were found, and --line-buffered was not being honoured.
816    12. Added an optional parentheses number to the -o and --only-matching options
817        of pcregrep.
819    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
820        can match an empty string. The code to do it in pcretest and pcredemo
821        needed fixing:
823        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
824            only one byte after an empty string match just before CRLF (this case
825            just got forgotten; "any" and "anycrlf" were OK).
827        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
828            mode when an empty string match preceded an ASCII character followed by
829            a non-ASCII character. (The code for advancing by one character rather
830            than one byte was nonsense.)
832        (c) The pcredemo.c sample program did not have any code at all to handle
833            the cases when CRLF is a valid newline sequence.
835    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
836        as a starting offset was within the subject string. There is now a new
837        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
838        negative or greater than the length of the string. In order to test this,
839        pcretest is extended to allow the setting of negative starting offsets.
841    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
842        starting offset points to the beginning of a UTF-8 character was
843        unnecessarily clumsy. I tidied it up.
845    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
846        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
848    17. Nobody had reported that the --include_dir option, which was added in
849        release 7.7 should have been called --include-dir (hyphen, not underscore)
850        for compatibility with GNU grep. I have changed it to --include-dir, but
851        left --include_dir as an undocumented synonym, and the same for
852        --exclude-dir, though that is not available in GNU grep, at least as of
853        release 2.5.4.
855    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
856        characters from a string of bytes) have been redefined so as not to use
857        loops, in order to improve performance in some environments. At the same
858        time, I abstracted some of the common code into auxiliary macros to save
859        repetition (this should not affect the compiled code).
861    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
862        compile-time error is now given if \c is not followed by an ASCII
863        character, that is, a byte less than 128. (In EBCDIC mode, the code is
864        different, and any byte value is allowed.)
866    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
867        START_OPTIMIZE option, which is now allowed at compile time - but just
868        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
869        to pcregrep and other applications that have no direct access to PCRE
870        options. The new /Y option in pcretest sets this option when calling
871        pcre_compile().
873    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
874        back references. Groups containing recursive back references were forced to
875        be atomic by that change, but in the case of named groups, the amount of
876        memory required was incorrectly computed, leading to "Failed: internal
877        error: code overflow". This has been fixed.
879    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
880        pcretest.c, to avoid build problems in some Borland environments.
883    Version 8.10 25-Jun-2010
884    ------------------------
886    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
887        THEN.
889    2.  (*ACCEPT) was not working when inside an atomic group.
891    3.  Inside a character class, \B is treated as a literal by default, but
892        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
893        causes the error). The code is unchanged, but I tidied the documentation.
895    4.  Inside a character class, PCRE always treated \R and \X as literals,
896        whereas Perl faults them if its -w option is set. I have changed PCRE so
897        that it faults them when PCRE_EXTRA is set.
899    5.  Added support for \N, which always matches any character other than
900        newline. (It is the same as "." when PCRE_DOTALL is not set.)
902    6.  When compiling pcregrep with newer versions of gcc which may have
903        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
904        declared with attribute warn_unused_result" were given. Just casting the
905        result to (void) does not stop the warnings; a more elaborate fudge is
906        needed. I've used a macro to implement this.
908    7.  Minor change to pcretest.c to avoid a compiler warning.
910    8.  Added four artifical Unicode properties to help with an option to make
911        \s etc use properties (see next item). The new properties are: Xan
912        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
914    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
915        use Unicode properties. (*UCP) at the start of a pattern can be used to set
916        this option. Modified pcretest to add /W to test this facility. Added
917        REG_UCP to make it available via the POSIX interface.
919    10. Added --line-buffered to pcregrep.
921    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
922        studied, and the match started with a letter with a code point greater than
923        127 whose first byte was different to the first byte of the other case of
924        the letter, the other case of this starting letter was not recognized
925        (#976).
927    12. If a pattern that was studied started with a repeated Unicode property
928        test, for example, \p{Nd}+, there was the theoretical possibility of
929        setting up an incorrect bitmap of starting bytes, but fortunately it could
930        not have actually happened in practice until change 8 above was made (it
931        added property types that matched character-matching opcodes).
933    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
934        possible starting bytes for non-anchored patterns.
936    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
937        \R, and also a number of cases that involve Unicode properties, both
938        explicit and implicit when PCRE_UCP is set.
940    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
941        input, it could crash or give wrong results if characters with values
942        greater than 0xc0 were present in the subject string. (Detail: it assumed
943        UTF-8 input when processing these items.)
945    16. Added a lot of (int) casts to avoid compiler warnings in systems where
946        size_t is 64-bit (#991).
948    17. Added a check for running out of memory when PCRE is compiled with
949        --disable-stack-for-recursion (#990).
951    18. If the last data line in a file for pcretest does not have a newline on
952        the end, a newline was missing in the output.
954    19. The default pcre_chartables.c file recognizes only ASCII characters (values
955        less than 128) in its various bitmaps. However, there is a facility for
956        generating tables according to the current locale when PCRE is compiled. It
957        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
958        characters, are recognized by isspace() and therefore were getting set in
959        these tables, and indeed these tables seem to approximate to ISO 8859. This
960        caused a problem in UTF-8 mode when pcre_study() was used to create a list
961        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
962        which of course cannot start UTF-8 characters. I have changed the code so
963        that only real ASCII characters (less than 128) and the correct starting
964        bytes for UTF-8 encodings are set for characters greater than 127 when in
965        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
966        altogether.)
968    20. Added the /T option to pcretest so as to be able to run tests with non-
969        standard character tables, thus making it possible to include the tests
970        used for 19 above in the standard set of tests.
972    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
973        reference to a subpattern the other side of a comment that contains an
974        opening parenthesis caused either an internal compiling error, or a
975        reference to the wrong subpattern.
978    Version 8.02 19-Mar-2010
979    ------------------------
981    1.  The Unicode data tables have been updated to Unicode 5.2.0.
983    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
984        configured.
986    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
987        original author of that file, following a query about its status.
989    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
990        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
992    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
993        quantifier applied to a forward-referencing subroutine call, could compile
994        incorrect code or give the error "internal error: previously-checked
995        referenced subpattern not found".
997    6.  Both MS Visual Studio and Symbian OS have problems with initializing
998        variables to point to external functions. For these systems, therefore,
999        pcre_malloc etc. are now initialized to local functions that call the
1000        relevant global functions.
1002    7.  There were two entries missing in the vectors called coptable and poptable
1003        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1004        I've fixed the data, and added a kludgy way of testing at compile time that
1005        the lengths are correct (equal to the number of opcodes).
1007    8.  Following on from 7, I added a similar kludge to check the length of the
1008        eint vector in pcreposix.c.
1010    9.  Error texts for pcre_compile() are held as one long string to avoid too
1011        much relocation at load time. To find a text, the string is searched,
1012        counting zeros. There was no check for running off the end of the string,
1013        which could happen if a new error number was added without updating the
1014        string.
1016    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1018    11. \K was not working if it appeared in an atomic group or in a group that
1019        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1020        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1021        the assertion is positive, but not if it is negative.
1023    12. Change 11 fortuitously reduced the size of the stack frame used in the
1024        "match()" function of pcre_exec.c by one pointer. Forthcoming
1025        implementation of support for (*MARK) will need an extra pointer on the
1026        stack; I have reserved it now, so that the stack frame size does not
1027        decrease.
1029    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1030        item in branch that calls a recursion is a subroutine call - as in the
1031        second branch in the above example - was incorrectly given the compile-
1032        time error "recursive call could loop indefinitely" because pcre_compile()
1033        was not correctly checking the subroutine for matching a non-empty string.
1035    14. The checks for overrunning compiling workspace could trigger after an
1036        overrun had occurred. This is a "should never occur" error, but it can be
1037        triggered by pathological patterns such as hundreds of nested parentheses.
1038        The checks now trigger 100 bytes before the end of the workspace.
1040    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1043    Version 8.01 19-Jan-2010
1044    ------------------------
1046    1.  If a pattern contained a conditional subpattern with only one branch (in
1047        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1048        computed the wrong minimum data length (which is of course zero for such
1049        subpatterns). This could cause incorrect "no match" results.
1051    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1052        the pattern is reset in the first branch, pcre_compile() failed with
1053        "internal error: code overflow at offset...". This happened only when
1054        the reset was to the original external option setting. (An optimization
1055        abstracts leading options settings into an external setting, which was the
1056        cause of this.)
1058    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1059        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1060        assertion pattern did not match (meaning that the assertion was true), it
1061        was incorrectly treated as false if the SKIP had been reached during the
1062        matching. This also applied to assertions used as conditions.
1064    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1065        assertion subpattern, including such a pattern used as a condition,
1066        unpredictable results occurred, instead of the error return
1069    5.  The C++ GlobalReplace function was not working like Perl for the special
1070        situation when an empty string is matched. It now does the fancy magic
1071        stuff that is necessary.
1073    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1074        removed. (These were left over from very, very early versions of PCRE.)
1076    7.  Some cosmetic changes to the code to make life easier when compiling it
1077        as part of something else:
1079        (a) Change DEBUG to PCRE_DEBUG.
1081        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1082            called "current" as "current_branch", to prevent a collision with the
1083            Linux macro when compiled as a kernel module.
1085        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1086            prevent a collision with the Linux macro when compiled as a kernel
1087            module.
1089    8.  In pcre_compile() there are some checks for integer overflows that used to
1090        cast potentially large values to (double). This has been changed to that
1091        when building, a check for int64_t is made, and if it is found, it is used
1092        instead, thus avoiding the use of floating point arithmetic. (There is no
1093        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1094        double.
1096    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1097        2005 (difference between two addresses compared to an unsigned value).
1099    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1100        custom one, because of the following reported problem in Windows:
1102          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1103              under Win32.
1104          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1105              therefore missing the function definition.
1106          - The compiler thus generates a "C" signature for the test function.
1107          - The linker fails to find the "C" function.
1108          - PCRE fails to configure if asked to do so against libbz2.
1110    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1111        messages were output:
1113          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1114          rerunning libtoolize, to keep the correct libtool macros in-tree.
1115          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1117        I have done both of these things.
1119    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1120        most of the time, it *can* run out if it is given a pattern that contains a
1121        runaway infinite recursion. I updated the discussion in the pcrestack man
1122        page.
1124    13. Now that we have gone to the x.xx style of version numbers, the minor
1125        version may start with zero. Using 08 or 09 is a bad idea because users
1126        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1127        interpreted as invalid octal numbers. I've updated the previous comment in
1128        configure.ac, and also added a check that gives an error if 08 or 09 are
1129        used.
1131    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1132        causing partial matching to fail when the end of the subject matched \W
1133        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1135    15. There were some discrepancies between the declarations in pcre_internal.h
1136        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1137        their definitions. The declarations used "const uschar *" and the
1138        definitions used USPTR. Even though USPTR is normally defined as "const
1139        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1140        reported that: "This difference in casting confuses some C++ compilers, for
1141        example, SunCC recognizes above declarations as different functions and
1142        generates broken code for hbpcre." I have changed the declarations to use
1143        USPTR.
1145    16. GNU libtool is named differently on some systems. The autogen.sh script now
1146        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1147        (FreeBSD).
1149    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1150        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1151        comment: "Figure out how to create a longlong from a string: strtoll and
1152        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1153        instance, but it only takes 2 args instead of 3!"
1155    18. A subtle bug concerned with back references has been fixed by a change of
1156        specification, with a corresponding code fix. A pattern such as
1157        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1158        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1159        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1160        same bug. Such groups have to be quantified to be useful, or contained
1161        inside another quantified group. (If there's no repetition, the reference
1162        can never match.) The problem arises because, having left the group and
1163        moved on to the rest of the pattern, a later failure that backtracks into
1164        the group uses the captured value from the final iteration of the group
1165        rather than the correct earlier one. I have fixed this in PCRE by forcing
1166        any group that contains a reference to itself to be an atomic group; that
1167        is, there cannot be any backtracking into it once it has completed. This is
1168        similar to recursive and subroutine calls.
1171    Version 8.00 19-Oct-09
1172    ----------------------
1174    1.  The table for translating pcre_compile() error codes into POSIX error codes
1175        was out-of-date, and there was no check on the pcre_compile() error code
1176        being within the table. This could lead to an OK return being given in
1177        error.
1179    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1180        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1181        in a Windows environment.
1183    3.  The pcregrep --count option prints the count for each file even when it is
1184        zero, as does GNU grep. However, pcregrep was also printing all files when
1185        --files-with-matches was added. Now, when both options are given, it prints
1186        counts only for those files that have at least one match. (GNU grep just
1187        prints the file name in this circumstance, but including the count seems
1188        more useful - otherwise, why use --count?) Also ensured that the
1189        combination -clh just lists non-zero counts, with no names.
1191    4.  The long form of the pcregrep -F option was incorrectly implemented as
1192        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1193        but it seems right to fix it, and I didn't think it was worth preserving
1194        the old behaviour.
1196    5.  The command line items --regex=pattern and --regexp=pattern were not
1197        recognized by pcregrep, which required --regex pattern or --regexp pattern
1198        (with a space rather than an '='). The man page documented the '=' forms,
1199        which are compatible with GNU grep; these now work.
1201    6.  No libpcreposix.pc file was created for pkg-config; there was just
1202        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1204    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1205        when UCP support is not needed, by modifying the Python script that
1206        generates it from Unicode data files. This should not matter if the module
1207        is correctly used as a library, but I received one complaint about 50K of
1208        unwanted data. My guess is that the person linked everything into his
1209        program rather than using a library. Anyway, it does no harm.
1211    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1212        was a minimum greater than 1 for a wide character in a possessive
1213        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1214        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1215        character. Chaos in the form of incorrect output or a compiling loop could
1216        result.
1218    9.  The restrictions on what a pattern can contain when partial matching is
1219        requested for pcre_exec() have been removed. All patterns can now be
1220        partially matched by this function. In addition, if there are at least two
1221        slots in the offset vector, the offset of the earliest inspected character
1222        for the match and the offset of the end of the subject are set in them when
1223        PCRE_ERROR_PARTIAL is returned.
1225    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1226        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1227        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1228        and may be more useful for multi-segment matching.
1230    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1231        used to be given if ever the end of the subject was reached; now it is
1232        given only if matching could not proceed because another character was
1233        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1234        string "Z", which now yields "no match" instead of "partial match". In the
1235        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1236        final character ended with (*FAIL).
1238    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1239        if the pattern had a "must contain" character that was already found in the
1240        earlier partial match, unless partial matching was again requested. For
1241        example, with the pattern /dog.(body)?/, the "must contain" character is
1242        "g". If the first part-match was for the string "dog", restarting with
1243        "sbody" failed. This bug has been fixed.
1245    13. The string returned by pcre_dfa_exec() after a partial match has been
1246        changed so that it starts at the first inspected character rather than the
1247        first character of the match. This makes a difference only if the pattern
1248        starts with a lookbehind assertion or \b or \B (\K is not supported by
1249        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1250        matching functions compatible, and I think it's the right thing to do.
1252    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1253        so that the demonstration program is easily available in environments where
1254        PCRE has not been installed from source.
1256    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1257        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1258        library.
1260    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1261        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1262        is not the first non-POSIX option to be added. Clearly some people find
1263        these options useful.
1265    17. If a caller to the POSIX matching function regexec() passes a non-zero
1266        value for nmatch with a NULL value for pmatch, the value of
1267        nmatch is forced to zero.
1269    18. RunGrepTest did not have a test for the availability of the -u option of
1270        the diff command, as RunTest does. It now checks in the same way as
1271        RunTest, and also checks for the -b option.
1273    19. If an odd number of negated classes containing just a single character
1274        interposed, within parentheses, between a forward reference to a named
1275        subpattern and the definition of the subpattern, compilation crashed with
1276        an internal error, complaining that it could not find the referenced
1277        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1278        [The bug was that it was starting one character too far in when skipping
1279        over the character class, thus treating the ] as data rather than
1280        terminating the class. This meant it could skip too much.]
1282    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1283        /g option in pcretest when the pattern contains \K, which makes it possible
1284        to have an empty string match not at the start, even when the pattern is
1285        anchored. Updated pcretest and pcredemo to use this option.
1287    21. If the maximum number of capturing subpatterns in a recursion was greater
1288        than the maximum at the outer level, the higher number was returned, but
1289        with unset values at the outer level. The correct (outer level) value is
1290        now given.
1292    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1293        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1294        make it do so. The string so far is captured, making this feature
1295        compatible with Perl.
1297    23. The tests have been re-organized, adding tests 11 and 12, to make it
1298        possible to check the Perl 5.10 features against Perl 5.10.
1300    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1301        pattern matches a fixed length string. PCRE did not allow this; now it
1302        does. Neither allows recursion.
1304    25. I finally figured out how to implement a request to provide the minimum
1305        length of subject string that was needed in order to match a given pattern.
1306        (It was back references and recursion that I had previously got hung up
1307        on.) This code has now been added to pcre_study(); it finds a lower bound
1308        to the length of subject needed. It is not necessarily the greatest lower
1309        bound, but using it to avoid searching strings that are too short does give
1310        some useful speed-ups. The value is available to calling programs via
1311        pcre_fullinfo().
1313    26. While implementing 25, I discovered to my embarrassment that pcretest had
1314        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1315        study optimizations had never been tested with that matching function.
1316        Oops. What is worse, even when it was passed study data, there was a bug in
1317        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1318        were also very few tests of studied patterns with pcre_dfa_exec().
1320    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1321        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1322        on the other side of the coin, they are no longer allowed to have different
1323        names, because these cannot be distinguished in PCRE, and this has caused
1324        confusion. (This is a difference from Perl.)
1326    28. When duplicate subpattern names are present (necessarily with different
1327        numbers, as required by 27 above), and a test is made by name in a
1328        conditional pattern, either for a subpattern having been matched, or for
1329        recursion in such a pattern, all the associated numbered subpatterns are
1330        tested, and the overall condition is true if the condition is true for any
1331        one of them. This is the way Perl works, and is also more like the way
1332        testing by number works.
1335    Version 7.9 11-Apr-09
1336    ---------------------
1338    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1339        (pcretest), all targets were linked against these libraries. This included
1340        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1341        libraries. This caused unwanted dependencies to be created. This problem
1342        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1343        pcretest is linked with readline.
1345    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1346        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1347        moved outside it again, because FALSE and TRUE are already defined in AIX,
1348        but BOOL is not.
1350    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1351        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1353    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1354        hyphens) following file names and line numbers when outputting matching
1355        lines. This is not true; no spaces are inserted. I have also clarified the
1356        wording for the --colour (or --color) option.
1358    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1359        was not coloured; this is different to GNU grep, so I have changed it to be
1360        the same.
1362    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1363        each matching line was coloured. Now it goes on to look for further matches
1364        of any of the test patterns, which is the same behaviour as GNU grep.
1366    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1367        doesn't make sense to accept an empty string match in pcregrep, so I have
1368        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1369        seems to be how GNU grep behaves.
1371    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1372        start or after a newline", because the conditional assertion was not being
1373        correctly handled. The rule now is that both the assertion and what follows
1374        in the first alternative must satisfy the test.
1376    9.  If auto-callout was enabled in a pattern with a conditional group whose
1377        condition was an assertion, PCRE could crash during matching, both with
1378        pcre_exec() and pcre_dfa_exec().
1380    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1381        used for matching.
1383    11. Unicode property support in character classes was not working for
1384        characters (bytes) greater than 127 when not in UTF-8 mode.
1386    12. Added the -M command line option to pcretest.
1388    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1390    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1392    16. Added comments and documentation about mis-use of no_arg in the C++
1393        wrapper.
1395    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1396        from Martin Jerabek that uses macro names for all relevant character and
1397        string constants.
1399    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1400        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1401        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1402        these, but not everybody uses configure.
1404    19. A conditional group that had only one branch was not being correctly
1405        recognized as an item that could match an empty string. This meant that an
1406        enclosing group might also not be so recognized, causing infinite looping
1407        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1408        with the subject "ab", where knowledge that the repeated group can match
1409        nothing is needed in order to break the loop.
1411    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1412        exec(), but without supplying a callout function, matching went wrong.
1414    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1415        leak if the size of the offset vector was greater than 30. When the vector
1416        is smaller, the saved offsets during recursion go onto a local stack
1417        vector, but for larger vectors malloc() is used. It was failing to free
1418        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1419        error, in fact).
1421    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1422        heapframe that is used only when UTF-8 support is enabled. This caused no
1423        problem, but was untidy.
1425    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1426        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1427        included within another project.
1429    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1430        slightly modified by me:
1432          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1433              not building pcregrep.
1435          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1436              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1438    25. Forward references, both numeric and by name, in patterns that made use of
1439        duplicate group numbers, could behave incorrectly or give incorrect errors,
1440        because when scanning forward to find the reference group, PCRE was not
1441        taking into account the duplicate group numbers. A pattern such as
1442        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1444    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1445        the feature of a custom pointer more persuasive (as requested by a user).
1447    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1448        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1449        pre-defined.
1451    28. Added support for (*UTF8) at the start of a pattern.
1453    29. Arrange for flags added by the "release type" setting in CMake to be shown
1454        in the configuration summary.
1457    Version 7.8 05-Sep-08
1458    ---------------------
1460    1.  Replaced UCP searching code with optimized version as implemented for Ad
1461        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1462        stage table and inline lookup instead of a function, giving speed ups of 2
1463        to 5 times on some simple patterns that I tested. Permission was given to
1464        distribute the MultiStage2.py script that generates the tables (it's not in
1465        the tarball, but is in the Subversion repository).
1467    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1468        scripts.
1470    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1471        a group with a zero qualifier. The result of the study could be incorrect,
1472        or the function might crash, depending on the pattern.
1474    4.  Caseless matching was not working for non-ASCII characters in back
1475        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1476        It now works when Unicode Property Support is available.
1478    5.  In pcretest, an escape such as \x{de} in the data was always generating
1479        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1480        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1481        truncation.
1483    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1485    7.  Added two (int) casts to pcregrep when printing the difference of two
1486        pointers, in case they are 64-bit values.
1488    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1489        test 2 if it fails.
1491    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1492        and a #define of that name to empty if it is not externally set. This is to
1493        allow users of MSVC to set it if necessary.
1495    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1496        the convenience functions in the pcre_get.c source file.
1498    11. An option change at the start of a pattern that had top-level alternatives
1499        could cause overwriting and/or a crash. This command provoked a crash in
1500        some environments:
1502          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1504        This potential security problem was recorded as CVE-2008-2371.
1506    12. For a pattern where the match had to start at the beginning or immediately
1507        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1508        pcre_dfa_exec() could read past the end of the passed subject if there was
1509        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1510        pcretest so that it places the subject at the end of its malloc-ed buffer.
1512    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1513        exec() might read past the end of the data buffer in UTF-8 mode.
1515    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1516        the data contained the byte 0x85 as part of a UTF-8 character within its
1517        first line. This applied both to normal and DFA matching.
1519    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1520        /^[^d]*?$/8 failed to match "abc".
1522    16. Added a missing copyright notice to pcrecpp_internal.h.
1524    17. Make it more clear in the documentation that values returned from
1525        pcre_exec() in ovector are byte offsets, not character counts.
1527    18. Tidied a few places to stop certain compilers from issuing warnings.
1529    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1530        supplied by Stefan Weber. I made a further small update for 7.8 because
1531        there is a change of source arrangements: the pcre_searchfuncs.c module is
1532        replaced by pcre_ucd.c.
1535    Version 7.7 07-May-08
1536    ---------------------
1538    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1539        a string to a long long, pretend we don't even have a long long." This is
1540        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1542    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1543        pre-7.6 versions, which defined a global no_arg variable instead of putting
1544        it in the RE class. (See also #8 below.)
1546    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1547        Lopes.
1549    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1551        (1) The include/exclude patterns were being applied to the whole pathnames
1552            of files, instead of just to the final components.
1554        (2) If there was more than one level of directory, the subdirectories were
1555            skipped unless they satisfied the include/exclude conditions. This is
1556            inconsistent with GNU grep (and could even be seen as contrary to the
1557            pcregrep specification - which I improved to make it absolutely clear).
1558            The action now is always to scan all levels of directory, and just
1559            apply the include/exclude patterns to regular files.
1561    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1562        --exclude_dir in the tests to avoid scanning .svn directories.
1564    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1565        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1566        doesn't support NULs in patterns.
1568    7.  Added some missing "const"s to declarations of static tables in
1569        pcre_compile.c and pcre_dfa_exec.c.
1571    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1572        caused by fix #2  above. (Subsequently also a second patch to fix the
1573        first patch. And a third patch - this was a messy problem.)
1575    9.  Applied Craig's patch to remove the use of push_back().
1577    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1578        matching function regexec().
1580    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1581        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1582        references. PCRE supports relative numbers with this syntax (I don't think
1583        Oniguruma does).
1585    12. Previously, a group with a zero repeat such as (...){0} was completely
1586        omitted from the compiled regex. However, this means that if the group
1587        was called as a subroutine from elsewhere in the pattern, things went wrong
1588        (an internal error was given). Such groups are now left in the compiled
1589        pattern, with a new opcode that causes them to be skipped at execution
1590        time.
1592    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1593        to the way PCRE behaves:
1595        (a) A lone ] character is dis-allowed (Perl treats it as data).
1597        (b) A back reference to an unmatched subpattern matches an empty string
1598            (Perl fails the current match path).
1600        (c) A data ] in a character class must be notated as \] because if the
1601            first data character in a class is ], it defines an empty class. (In
1602            Perl it is not possible to have an empty class.) The empty class []
1603            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1604            The negative empty class [^] matches any one character, independently
1605            of the DOTALL setting.
1607    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1608        non-existent subpattern following a character class starting with ']' and
1609        containing () gave an internal compiling error instead of "reference to
1610        non-existent subpattern". Fortunately, when the pattern did exist, the
1611        compiled code was correct. (When scanning forwards to check for the
1612        existencd of the subpattern, it was treating the data ']' as terminating
1613        the class, so got the count wrong. When actually compiling, the reference
1614        was subsequently set up correctly.)
1616    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1617        it was being rejected as not supported by pcre_dfa_exec(), even though
1618        other assertions are supported. I have made pcre_dfa_exec() support
1619        (*FAIL).
1621    16. The implementation of 13c above involved the invention of a new opcode,
1622        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1623        cannot be changed at match time, I realized I could make a small
1624        improvement to matching performance by compiling OP_ALLANY instead of
1625        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1626        on the OP_ANY path.
1628    17. Compiling pcretest on Windows with readline support failed without the
1629        following two fixes: (1) Make the unistd.h include conditional on
1630        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1632    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1633        ncurses library to be included for pcretest when ReadLine support is
1634        requested, but also to allow for it to be overridden. This patch came from
1635        Daniel Bergström.
1637    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1638        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1639        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1640        spotting this.
1643    Version 7.6 28-Jan-08
1644    ---------------------
1646    1.  A character class containing a very large number of characters with
1647        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1648        overflow.
1650    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1651        HAVE_LONG_LONG is not defined.
1653    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1654        bring them up to date and include new features. This patch includes:
1656        - Fixed PH's badly added libz and libbz2 support.
1657        - Fixed a problem with static linking.
1658        - Added pcredemo. [But later removed - see 7 below.]
1659        - Fixed dftables problem and added an option.
1660        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1661            HAVE_LONG_LONG.
1662        - Added readline support for pcretest.
1663        - Added an listing of the option settings after cmake has run.
1665    4.  A user submitted a patch to Makefile that makes it easy to create
1666        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1667        Makefile.am that cause it to include this special target, without
1668        affecting anything else. Note that the same mingw target plus all
1669        the other distribution libraries and programs are now supported
1670        when configuring with CMake (see 6 below) instead of with
1671        Configure/Make.
1673    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1674        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1675        exported in the Windows port". It has not yet been confirmed that the patch
1676        solves the problem, but it does no harm.
1678    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1679        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1680        with CMake, and also correct the comment about stack recursion.
1682    7.  Remove the automatic building of pcredemo from the ./configure system and
1683        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1684        of a program that users should build themselves after PCRE is installed, so
1685        building it automatically is not really right. What is more, it gave
1686        trouble in some build environments.
1688    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1691    Version 7.5 10-Jan-08
1692  ---------------------  ---------------------
1694  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1695      values in parens when parsing an RE using the C++ wrapper."      values in parens when parsing an RE using the C++ wrapper."
1697  2.  Negative specials like \S did not work in character classes in UTF-8 mode.  2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1698      Characters greater than 255 were excluded from the class instead of being      Characters greater than 255 were excluded from the class instead of being
1699      included.      included.
1701  3.  The same bug as (2) above applied to negated POSIX classes such as  3.  The same bug as (2) above applied to negated POSIX classes such as
1702      [:^space:].      [:^space:].
1704  4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it  4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1705      defined or documented. It seems to have been a typo for PCRE_STATIC, so      defined or documented. It seems to have been a typo for PCRE_STATIC, so
1706      I have changed it.      I have changed it.
1708  5.  The construct (?&) was not diagnosed as a syntax error (it referenced the  5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1709      first named subpattern) and a construct such as (?&a) would reference the      first named subpattern) and a construct such as (?&a) would reference the
1710      first named subpattern whose name started with "a" (in other words, the      first named subpattern whose name started with "a" (in other words, the
1711      length check was missing). Both these problems are fixed. "Subpattern name      length check was missing). Both these problems are fixed. "Subpattern name
1712      expected" is now given for (?&) (a zero-length name), and this patch also      expected" is now given for (?&) (a zero-length name), and this patch also
1713      makes it give the same error for \k'' (previously it complained that that      makes it give the same error for \k'' (previously it complained that that
1714      was a reference to a non-existent subpattern).      was a reference to a non-existent subpattern).
1716  6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;  6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1717      this is right because (?- can be followed by option settings as well as by      this is right because (?- can be followed by option settings as well as by
1718      digits. I have, however, made the messages clearer.      digits. I have, however, made the messages clearer.
1720  7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns  7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1721      than the number used in the conditional) now cause a compile-time error.      than the number used in the conditional) now cause a compile-time error.
1722      This is actually not compatible with Perl, which accepts such patterns, but      This is actually not compatible with Perl, which accepts such patterns, but
1723      treats the conditional as always being FALSE (as PCRE used to), but it      treats the conditional as always being FALSE (as PCRE used to), but it
1724      seems to me that giving a diagnostic is better.      seems to me that giving a diagnostic is better.
1726  8.  Change "alphameric" to the more common word "alphanumeric" in comments  8.  Change "alphameric" to the more common word "alphanumeric" in comments
1727      and messages.      and messages.
1729  9.  Fix two occurrences of "backslash" in comments that should have been  9.  Fix two occurrences of "backslash" in comments that should have been
1730      "backspace".      "backspace".
1732  10. Remove two redundant lines of code that can never be obeyed (their function  10. Remove two redundant lines of code that can never be obeyed (their function
1733      was moved elsewhere).      was moved elsewhere).
1735    11. The program that makes PCRE's Unicode character property table had a bug
1736        which caused it to generate incorrect table entries for sequences of
1737        characters that have the same character type, but are in different scripts.
1738        It amalgamated them into a single range, with the script of the first of
1739        them. In other words, some characters were in the wrong script. There were
1740        thirteen such cases, affecting characters in the following ranges:
1742          U+002b0 - U+002c1
1743          U+0060c - U+0060d
1744          U+0061e - U+00612
1745          U+0064b - U+0065e
1746          U+0074d - U+0076d
1747          U+01800 - U+01805
1748          U+01d00 - U+01d77
1749          U+01d9b - U+01dbf
1750          U+0200b - U+0200f
1751          U+030fc - U+030fe
1752          U+03260 - U+0327f
1753          U+0fb46 - U+0fbb1
1754          U+10450 - U+1049d
1756    12. The -o option (show only the matching part of a line) for pcregrep was not
1757        compatible with GNU grep in that, if there was more than one match in a
1758        line, it showed only the first of them. It now behaves in the same way as
1759        GNU grep.
1761    13. If the -o and -v options were combined for pcregrep, it printed a blank
1762        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1763        does the same. The return code can be used to tell if there were any
1764        non-matching lines.
1766    14. Added --file-offsets and --line-offsets to pcregrep.
1768    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1769        infinitely looping recursion. The bug was that positive lookaheads were not
1770        being skipped when checking for a possible empty match (negative lookaheads
1771        and both kinds of lookbehind were skipped).
1773    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1774        inclusion of <windows.h> to before rather than after the definition of
1775        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1777    17. Specifying a possessive quantifier with a specific limit for a Unicode
1778        character property caused pcre_compile() to compile bad code, which led at
1779        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1780        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1781        caused the error; without that there was no problem.
1783    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1785    19. Added --enable-pcretest-libreadline.
1787    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1788        RE::GlobalReplace(). As a result, the number of replacements returned was
1789        double what it should be. I removed one of the increments, but Craig sent a
1790        later patch that removed the other one (the right fix) and added unit tests
1791        that check the return values (which was not done before).
1793    21. Several CMake things:
1795        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1796            the names libpcre and libpcreposix, not just pcre and pcreposix.
1798        (2) The above change means that pcretest and pcregrep are now correctly
1799            linked with the newly-built libraries, not previously installed ones.
1803    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1804        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1805        UTF-8 newline character). The key issue is that the pattern starts .*;
1806        this means that the match must be either at the beginning, or after a
1807        newline. The bug was in the code for advancing after a failed match and
1808        checking that the new position followed a newline. It was not taking
1809        account of UTF-8 characters correctly.
1811    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1812        character classes. PCRE was not treating the sequence [:...:] as a
1813        character class unless the ... were all letters. Perl, however, seems to
1814        allow any characters between [: and :], though of course it rejects as
1815        unknown any "names" that contain non-letters, because all the known class
1816        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1817        for example, whereas PCRE did not - it did not recognize a POSIX character
1818        class. This seemed a bit dangerous, so the code has been changed to be
1819        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1820        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1821        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1822        Perl does, and where it didn't before.
1824    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1825        Windows environments %n is disabled by default.
1828  Version 7.4 21-Sep-07  Version 7.4 21-Sep-07

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