ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 61 by nigel, Sat Feb 24 21:39:58 2007 UTC revision 986 by zherczeg, Sat Jul 7 03:33:54 2012 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 3.0 02-Jan-02  Version 8.32
5    ------------
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
11    Version 8.31 06-July-2012
12    -------------------------
14    1.  Fixing a wrong JIT test case and some compiler warnings.
16    2.  Removed a bashism from the RunTest script.
18    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
19        to unsigned type, result still unsigned" that was given by an MS compiler
20        on encountering the code "-sizeof(xxx)".
22    4.  Partial matching support is added to the JIT compiler.
24    5.  Fixed several bugs concerned with partial matching of items that consist
25        of more than one character:
27        (a) /^(..)\1/ did not partially match "aba" because checking references was
28            done on an "all or nothing" basis. This also applied to repeated
29            references.
31        (b) \R did not give a hard partial match if \r was found at the end of the
32            subject.
34        (c) \X did not give a hard partial match after matching one or more
35            characters at the end of the subject.
37        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
38            a partial match for the string "\r".
40        (e) When newline was set to CRLF, the metacharacter "." did not recognize
41            a partial match for a CR character at the end of the subject string.
43    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
44        running pcretest, the text "(JIT)" added to the output whenever JIT is
45        actually used to run the match.
47    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
48        or /S+[+] with a digit between 1 and 7.
50    8.  OP_NOT now supports any UTF character not just single-byte ones.
52    9.  (*MARK) control verb is now supported by the JIT compiler.
54    10. The command "./RunTest list" lists the available tests without actually
55        running any of them. (Because I keep forgetting what they all are.)
59    12. Applied a (slightly modified) user-supplied patch that improves performance
60        when the heap is used for recursion (compiled with --disable-stack-for-
61        recursion). Instead of malloc and free for each heap frame each time a
62        logical recursion happens, frames are retained on a chain and re-used where
63        possible. This sometimes gives as much as 30% improvement.
65    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
66        call.
68    14. As documented, (*COMMIT) is now confined to within a positive assertion.
70    15. It is now possible to link pcretest with libedit as an alternative to
71        libreadline.
73    16. (*COMMIT) control verb is now supported by the JIT compiler.
75    17. The Unicode data tables have been updated to Unicode 6.1.0.
77    18. Added --file-list option to pcregrep.
79    19. Added binary file support to pcregrep, including the -a, --binary-files,
80        -I, and --text options.
82    20. The madvise function is renamed for posix_madvise for QNX compatibility
83        reasons. Fixed by Giuseppe D'Angelo.
85    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
87    22. Changed the option for creating symbolic links for 16-bit man pages from
88        -s to -sf so that re-installing does not cause issues.
90    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
92    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
93        matches in certain environments (the workspace was not being correctly
94        retained). Also added to pcre_dfa_exec() a simple plausibility check on
95        some of the workspace data at the beginning of a restart.
97    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
98        was not doing so when it should - probably a typo introduced by SVN 528
99        (change 8.10/14).
101    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
102        \w+ when the character tables indicated that \x{c4} was a word character.
103        There were several related cases, all because the tests for doing a table
104        lookup were testing for characters less than 127 instead of 255.
106    27. If a pattern contains capturing parentheses that are not used in a match,
107        their slots in the ovector are set to -1. For those that are higher than
108        any matched groups, this happens at the end of processing. In the case when
109        there were back references that the ovector was too small to contain
110        (causing temporary malloc'd memory to be used during matching), and the
111        highest capturing number was not used, memory off the end of the ovector
112        was incorrectly being set to -1. (It was using the size of the temporary
113        memory instead of the true size.)
115    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
116        ovector size, it uses memory at the end of the block that it has got.
118    29. Check for an overlong MARK name and give an error at compile time. The
119        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
121    30. JIT compiler update.
123    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
124        Rill for the patch.
126    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
128    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
130    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
131        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
132        was enabled.
134    35. Improve JIT code generation for greedy plus quantifier.
136    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
137        1 to "aa" instead of to an empty string. The bug affected repeated groups
138        that could potentially match an empty string.
140    37. Optimizing single character iterators in JIT.
142    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
143        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
144        codepoints that are too big for the mode are faulted, and in a UTF mode,
145        disallowed codepoints are also faulted.
147    39. If PCRE was compiled with UTF support, in three places in the DFA
148        matcher there was code that should only have been obeyed in UTF mode, but
149        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
150        processing when bytes with values greater than 127 were present. In 16-bit
151        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
152        both cases the values are those that cannot be the first data item in a UTF
153        character. The three items that might have provoked this were recursions,
154        possessively repeated groups, and atomic groups.
156    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
157        and pcregrep, because some OS require shared objects to be explicitly
158        passed to ld, causing the link step to fail if they are not.
160    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
161        mode, patterns that started with \h* or \R* might be incorrectly matched.
164    Version 8.30 04-February-2012
165    -----------------------------
167    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
168        name is defined in ctype.h.
170    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
171        only in quite long subpatterns.
173    3.  Removed the function pcre_info(), which has been obsolete and deprecated
174        since it was replaced by pcre_fullinfo() in February 2000.
176    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
177        match a (*MARK), and the match failed at the start of the subject, a
178        reference to memory before the start of the subject could occur. This bug
179        was introduced by fix 17 of release 8.21.
181    5.  A reference to an unset group with zero minimum repetition was giving
182        totally wrong answers (in non-JavaScript-compatibility mode). For example,
183        /(another)?(\1?)test/ matched against "hello world test". This bug was
184        introduced in release 8.13.
186    6.  Add support for 16-bit character strings (a large amount of work involving
187        many changes and refactorings).
189    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
190        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
191        from a file.
193    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
194        rounding is not applied in this particular case).
196    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
197        if they appear, or are escaped, in patterns.
199    10. Get rid of a number of -Wunused-but-set-variable warnings.
201    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
202        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
203        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
204        also returns the mark "x". This bug applied to capturing parentheses,
205        non-capturing parentheses, and atomic parentheses. It also applied to some
206        assertions.
208    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
209        information out of configure.ac instead of relying on pcre.h.generic, which
210        is not stored in the repository.
212    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
213        -lreadline.
215    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
217    15. Applied Graycode's patch to put the top-level frame on the stack rather
218        than the heap when not using the stack for recursion. This gives a
219        performance improvement in many cases when recursion is not deep.
221    16. Experimental code added to "pcretest -C" to output the stack frame size.
224    Version 8.21 12-Dec-2011
225    ------------------------
227    1.  Updating the JIT compiler.
229    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
230        are added as well.
232    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
233        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
234        calling _pcre_jit_exec. Some extra comments are added.
236    4.  (*MARK) settings inside atomic groups that do not contain any capturing
237        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
238        was introduced by change 18 for 8.20.
240    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
241        ECMA-262 standard.
243    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
244        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
245        This bug was probably introduced by change 9 of 8.13.
247    7.  While fixing 6 above, I noticed that a number of other items were being
248        incorrectly rejected as "not fixed length". This arose partly because newer
249        opcodes had not been added to the fixed-length checking code. I have (a)
250        corrected the bug and added tests for these items, and (b) arranged for an
251        error to occur if an unknown opcode is encountered while checking for fixed
252        length instead of just assuming "not fixed length". The items that were
253        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
254        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
255        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
257    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
258        being incorrectly compiled and would have given unpredicatble results.
260    9.  A possessively repeated subpattern with minimum repeat count greater than
261        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
262        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
263        the first (A) could occur when it should not.
265    10. Add a cast and remove a redundant test from the code.
267    11. JIT should use pcre_malloc/pcre_free for allocation.
269    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
270        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
271        is anything other than /usr, -L is still shown).
273    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
275    14. Perl does not support \N without a following name in a [] class; PCRE now
276        also gives an error.
278    15. If a forward reference was repeated with an upper limit of around 2000,
279        it caused the error "internal error: overran compiling workspace". The
280        maximum number of forward references (including repeats) was limited by the
281        internal workspace, and dependent on the LINK_SIZE. The code has been
282        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
283        the default depends on LINK_SIZE. There is a new upper limit (for safety)
284        of around 200,000 forward references. While doing this, I also speeded up
285        the filling in of repeated forward references.
287    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
288        incorrectly expecting the subject to contain another "a" after the start.
290    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
291        in the match, the SKIP should be ignored. This was not happening; instead
292        the SKIP was being treated as NOMATCH. For patterns such as
293        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
294        tested.
296    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
297        now much more compatible with Perl, in particular in cases where the result
298        is a non-match for a non-anchored pattern. For example, if
299        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
300        "m", where previously it did not return a name. A side effect of this
301        change is that for partial matches, the last encountered mark name is
302        returned, as for non matches. A number of tests that were previously not
303        Perl-compatible have been moved into the Perl-compatible test files. The
304        refactoring has had the pleasing side effect of removing one argument from
305        the match() function, thus reducing its stack requirements.
307    19. If the /S+ option was used in pcretest to study a pattern using JIT,
308        subsequent uses of /S (without +) incorrectly behaved like /S+.
310    21. Retrieve executable code size support for the JIT compiler and fixing
311        some warnings.
313    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
314        not work when the shorter character appeared right at the end of the
315        subject string.
317    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
318        systems.
320    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
321        output it when the /M option is used in pcretest.
323    25. The CheckMan script was not being included in the distribution. Also, added
324        an explicit "perl" to run Perl scripts from the PrepareRelease script
325        because this is reportedly needed in Windows.
327    26. If study data was being save in a file and studying had not found a set of
328        "starts with" bytes for the pattern, the data written to the file (though
329        never used) was taken from uninitialized memory and so caused valgrind to
330        complain.
332    27. Updated RunTest.bat as provided by Sheri Pierce.
334    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
336    29. Computation of memory usage for the table of capturing group names was
337        giving an unnecessarily large value.
340    Version 8.20 21-Oct-2011
341    ------------------------
343    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
344        a POSIX class. After further experiments with Perl, which convinced me that
345        Perl has bugs and confusions, a closing square bracket is no longer allowed
346        in a POSIX name. This bug also affected patterns with classes that started
347        with full stops.
349    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
350        captured substring, but while checking the failing first alternative,
351        substring 1 is temporarily captured. If the output vector supplied to
352        pcre_exec() was not big enough for this capture, the yield of the function
353        was still zero ("insufficient space for captured substrings"). This cannot
354        be totally fixed without adding another stack variable, which seems a lot
355        of expense for a edge case. However, I have improved the situation in cases
356        such as /(a)(b)x|abc/ matched against "abc", where the return code
357        indicates that fewer than the maximum number of slots in the ovector have
358        been set.
360    3.  Related to (2) above: when there are more back references in a pattern than
361        slots in the output vector, pcre_exec() uses temporary memory during
362        matching, and copies in the captures as far as possible afterwards. It was
363        using the entire output vector, but this conflicts with the specification
364        that only 2/3 is used for passing back captured substrings. Now it uses
365        only the first 2/3, for compatibility. This is, of course, another edge
366        case.
368    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
369        main code base, and can be used by building with --enable-jit. When this is
370        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
371        runtime --no-jit option is given.
373    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
374        ovector, the return from the function was zero, implying that there were
375        other matches that did not fit. The correct "exactly full" value is now
376        returned.
378    6.  If a subpattern that was called recursively or as a subroutine contained
379        (*PRUNE) or any other control that caused it to give a non-standard return,
380        invalid errors such as "Error -26 (nested recursion at the same subject
381        position)" or even infinite loops could occur.
383    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
384        computing the minimum length on reaching *ACCEPT, and so ended up with the
385        wrong value of 1 rather than 0. Further investigation indicates that
386        computing a minimum subject length in the presence of *ACCEPT is difficult
387        (think back references, subroutine calls), and so I have changed the code
388        so that no minimum is registered for a pattern that contains *ACCEPT.
390    8.  If (*THEN) was present in the first (true) branch of a conditional group,
391        it was not handled as intended. [But see 16 below.]
393    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
394        Sheri Pierce.
396    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
397        the first byte in a match must be "a".
399    11. Change 17 for 8.13 increased the recursion depth for patterns like
400        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
401        pattern contains any instances of (*THEN). If it does not, the old
402        optimizations are restored. It would be nice to do this on a per-group
403        basis, but at the moment that is not feasible.
405    12. In some environments, the output of pcretest -C is CRLF terminated. This
406        broke RunTest's code that checks for the link size. A single white space
407        character after the value is now allowed for.
409    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
410        For "fr", it uses the Windows-specific input and output files.
412    14. If (*THEN) appeared in a group that was called recursively or as a
413        subroutine, it did not work as intended. [But see next item.]
415    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
416        pattern fragments (but not containing any | characters). If A and B are
417        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
418        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
419        D. In other words, Perl considers parentheses that do not contain any |
420        characters to be part of a surrounding alternative, whereas PCRE was
421        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
422        differently. PCRE now behaves in the same way as Perl, except in the case
423        of subroutine/recursion calls such as (?1) which have in any case always
424        been different (but PCRE had them first :-).
426    16. Related to 15 above: Perl does not treat the | in a conditional group as
427        creating alternatives. Such a group is treated in the same way as an
428        ordinary group without any | characters when processing (*THEN). PCRE has
429        been changed to match Perl's behaviour.
431    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
432        RunGrepTest script failed.
434    18. Change 22 for version 13 caused atomic groups to use more stack. This is
435        inevitable for groups that contain captures, but it can lead to a lot of
436        stack use in large patterns. The old behaviour has been restored for atomic
437        groups that do not contain any capturing parentheses.
439    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
440        suppress the check for a minimum subject length at run time. (If it was
441        given to pcre_exec() or pcre_dfa_exec() it did work.)
443    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
444        fail to work when decoding hex characters in data strings in EBCDIC
445        environments.
447    21. It appears that in at least one Mac OS environment, the isxdigit() function
448        is implemented as a macro that evaluates to its argument more than once,
449        contravening the C 90 Standard (I haven't checked a later standard). There
450        was an instance in pcretest which caused it to go wrong when processing
451        \x{...} escapes in subject strings. The has been rewritten to avoid using
452        things like p++ in the argument of isxdigit().
455    Version 8.13 16-Aug-2011
456    ------------------------
458    1.  The Unicode data tables have been updated to Unicode 6.0.0.
460    2.  Two minor typos in pcre_internal.h have been fixed.
462    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
463        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
464        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
466    4.  There were a number of related bugs in the code for matching backrefences
467        caselessly in UTF-8 mode when codes for the characters concerned were
468        different numbers of bytes. For example, U+023A and U+2C65 are an upper
469        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
470        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
471        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
472        2-byte code at the end of the subject (it thought there wasn't enough data
473        left).
475    5.  Comprehensive information about what went wrong is now returned by
476        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
477        as the output vector has at least 2 elements. The offset of the start of
478        the failing character and a reason code are placed in the vector.
480    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
481        now returned is for the first byte of the failing character, instead of the
482        last byte inspected. This is an incompatible change, but I hope it is small
483        enough not to be a problem. It makes the returned offset consistent with
484        pcre_exec() and pcre_dfa_exec().
486    7.  pcretest now gives a text phrase as well as the error number when
487        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
488        failure, the offset and reason code are output.
490    8.  When \R was used with a maximizing quantifier it failed to skip backwards
491        over a \r\n pair if the subsequent match failed. Instead, it just skipped
492        back over a single character (\n). This seems wrong (because it treated the
493        two characters as a single entity when going forwards), conflicts with the
494        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
495        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
496        has been changed.
498    9.  Some internal refactoring has changed the processing so that the handling
499        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
500        time (the PCRE_DOTALL option was changed this way some time ago: version
501        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
502        which was always a bit of a fudge. It also means that there is one less
503        argument for the match() function, which reduces its stack requirements
504        slightly. This change also fixes an incompatibility with Perl: the pattern
505        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
507    10. More internal refactoring has drastically reduced the number of recursive
508        calls to match() for possessively repeated groups such as (abc)++ when
509        using pcre_exec().
511    11. While implementing 10, a number of bugs in the handling of groups were
512        discovered and fixed:
514        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
515        (a|)*(?1) gave a compile-time internal error.
516        ((a|)+)+  did not notice that the outer group could match an empty string.
517        (^a|^)+   was not marked as anchored.
518        (.*a|.*)+ was not marked as matching at start or after a newline.
520    12. Yet more internal refactoring has removed another argument from the match()
521        function. Special calls to this function are now indicated by setting a
522        value in a variable in the "match data" data block.
524    13. Be more explicit in pcre_study() instead of relying on "default" for
525        opcodes that mean there is no starting character; this means that when new
526        ones are added and accidentally left out of pcre_study(), testing should
527        pick them up.
529    14. The -s option of pcretest has been documented for ages as being an old
530        synonym of -m (show memory usage). I have changed it to mean "force study
531        for every regex", that is, assume /S for every regex. This is similar to -i
532        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
533        using it. It makes it easier to run collections of tests with and without
534        study enabled, and thereby test pcre_study() more easily. All the standard
535        tests are now run with and without -s (but some patterns can be marked as
536        "never study" - see 20 below).
538    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
539        restoration of the capturing data to the outer values was not happening
540        correctly.
542    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
543        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
544        pattern had matched an empty string, and so incorrectly returned a no
545        match.
547    17. There was optimizing code for the last branch of non-capturing parentheses,
548        and also for the obeyed branch of a conditional subexpression, which used
549        tail recursion to cut down on stack usage. Unfortunately, now that there is
550        the possibility of (*THEN) occurring in these branches, tail recursion is
551        no longer possible because the return has to be checked for (*THEN). These
552        two optimizations have therefore been removed. [But see 8.20/11 above.]
554    18. If a pattern containing \R was studied, it was assumed that \R always
555        matched two bytes, thus causing the minimum subject length to be
556        incorrectly computed because \R can also match just one byte.
558    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
559        was incorrectly computed.
561    20. If /S is present twice on a test pattern in pcretest input, it now
562        *disables* studying, thereby overriding the use of -s on the command line
563        (see 14 above). This is necessary for one or two tests to keep the output
564        identical in both cases.
566    21. When (*ACCEPT) was used in an assertion that matched an empty string and
567        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
569    22. When an atomic group that contained a capturing parenthesis was
570        successfully matched, but the branch in which it appeared failed, the
571        capturing was not being forgotten if a higher numbered group was later
572        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
573        group 1 to "a", when in fact it should be unset. This applied to multi-
574        branched capturing and non-capturing groups, repeated or not, and also to
575        positive assertions (capturing in negative assertions does not happen
576        in PCRE) and also to nested atomic groups.
578    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
579        subject after a captured substring, to make it easier to tell which of a
580        number of identical substrings has been captured.
582    24. The way atomic groups are processed by pcre_exec() has been changed so that
583        if they are repeated, backtracking one repetition now resets captured
584        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
585        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
586        "aaa". Previously, it would have been "a". As part of this code
587        refactoring, the way recursive calls are handled has also been changed.
589    25. If an assertion condition captured any substrings, they were not passed
590        back unless some other capturing happened later. For example, if
591        (?(?=(a))a) was matched against "a", no capturing was returned.
593    26. When studying a pattern that contained subroutine calls or assertions,
594        the code for finding the minimum length of a possible match was handling
595        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
596        group 1 called group 2 while simultaneously a separate group 2 called group
597        1). A stack overflow occurred in this case. I have fixed this by limiting
598        the recursion depth to 10.
600    27. Updated RunTest.bat in the distribution to the version supplied by Tom
601        Fortmann. This supports explicit test numbers on the command line, and has
602        argument validation and error reporting.
604    28. An instance of \X with an unlimited repeat could fail if at any point the
605        first character it looked at was a mark character.
607    29. Some minor code refactoring concerning Unicode properties and scripts
608        should reduce the stack requirement of match() slightly.
610    30. Added the '=' option to pcretest to check the setting of unused capturing
611        slots at the end of the pattern, which are documented as being -1, but are
612        not included in the return count.
614    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
615        compiled something random. Now it gives a compile-time error (as does
616        Perl).
618    32. A *MARK encountered during the processing of a positive assertion is now
619        recorded and passed back (compatible with Perl).
621    33. If --only-matching or --colour was set on a pcregrep call whose pattern
622        had alternative anchored branches, the search for a second match in a line
623        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
624        matched the line "0102" twice. The same bug affected patterns that started
625        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
626        twice.
628    34. Previously, PCRE did not allow quantification of assertions. However, Perl
629        does, and because of capturing effects, quantifying parenthesized
630        assertions may at times be useful. Quantifiers are now allowed for
631        parenthesized assertions.
633    35. A minor code tidy in pcre_compile() when checking options for \R usage.
635    36. \g was being checked for fancy things in a character class, when it should
636        just be a literal "g".
638    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
639        appearance of a nested POSIX class supersedes an apparent external class.
640        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
641        unescaped square brackets may also appear as part of class names. For
642        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
643        more like Perl. (But see 8.20/1 above.)
645    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
646        was because it thought it was \N{name}, which is not supported).
648    39. Add minix to OS list not supporting the -S option in pcretest.
650    40. PCRE tries to detect cases of infinite recursion at compile time, but it
651        cannot analyze patterns in sufficient detail to catch mutual recursions
652        such as ((?1))((?2)). There is now a runtime test that gives an error if a
653        subgroup is called recursively as a subpattern for a second time at the
654        same position in the subject string. In previous releases this might have
655        been caught by the recursion limit, or it might have run out of stack.
657    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
658        happen only once. PCRE was, however incorrectly giving a compile time error
659        "recursive call could loop indefinitely" because it cannot analyze the
660        pattern in sufficient detail. The compile time test no longer happens when
661        PCRE is compiling a conditional subpattern, but actual runaway loops are
662        now caught at runtime (see 40 above).
664    42. It seems that Perl allows any characters other than a closing parenthesis
665        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
666        has been changed to be the same.
668    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
669        as not to get warnings when autogen.sh is called. Also changed
670        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
672    44. To help people who use pcregrep to scan files containing exceedingly long
673        lines, the following changes have been made:
675        (a) The default value of the buffer size parameter has been increased from
676            8K to 20K. (The actual buffer used is three times this size.)
678        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
679            PCRE is built.
681        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
682            to be set at run time.
684        (d) Numerical values in pcregrep options can be followed by K or M, for
685            example --buffer-size=50K.
687        (e) If a line being scanned overflows pcregrep's buffer, an error is now
688            given and the return code is set to 2.
690    45. Add a pointer to the latest mark to the callout data block.
692    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
693        partial match of an empty string instead of no match. This was specific to
694        the use of ".".
696    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
697        complete match instead of a partial match. This bug was dependent on both
698        the PCRE_UTF8 and PCRE_DOTALL options being set.
700    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
701        starting byte set, because \b was not being ignored.
704    Version 8.12 15-Jan-2011
705    ------------------------
707    1.  Fixed some typos in the markup of the man pages, and wrote a script that
708        checks for such things as part of the documentation building process.
710    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
711        --match-limit and --recursion-limit options (added for 8.11). In
712        particular, this made one of the standard tests fail. (The integer value
713        went into the wrong half of a long int.)
715    3.  If the --colour option was given to pcregrep with -v (invert match), it
716        did strange things, either producing crazy output, or crashing. It should,
717        of course, ignore a request for colour when reporting lines that do not
718        match.
720    4.  Another pcregrep bug caused similar problems if --colour was specified with
721        -M (multiline) and the pattern match finished with a line ending.
723    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
724        matched in multiline mode, the following line was shown as part of the
725        match. This seems wrong, so I have changed it.
727    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
728        the check for further matches in the same line (so they could be coloured)
729        to overrun the end of the current line. If another match was found, it was
730        incorrectly shown (and then shown again when found in the next line).
732    7.  If pcregrep was compiled under Windows, there was a reference to the
733        function pcregrep_exit() before it was defined. I am assuming this was
734        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
735        reported by a user. I've moved the definition above the reference.
738    Version 8.11 10-Dec-2010
739    ------------------------
741    1.  (*THEN) was not working properly if there were untried alternatives prior
742        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
743        backtracked to try for "b" instead of moving to the next alternative branch
744        at the same level (in this case, to look for "c"). The Perl documentation
745        is clear that when (*THEN) is backtracked onto, it goes to the "next
746        alternative in the innermost enclosing group".
748    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
749        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
750        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
751        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
752        (*THEN).
754    3.  If \s appeared in a character class, it removed the VT character from
755        the class, even if it had been included by some previous item, for example
756        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
757        of \s, but is part of the POSIX "space" class.)
759    4.  A partial match never returns an empty string (because you can always
760        match an empty string at the end of the subject); however the checking for
761        an empty string was starting at the "start of match" point. This has been
762        changed to the "earliest inspected character" point, because the returned
763        data for a partial match starts at this character. This means that, for
764        example, /(?<=abc)def/ gives a partial match for the subject "abc"
765        (previously it gave "no match").
767    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
768        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
769        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
770        has an implication that the given string is incomplete (because a partial
771        match is preferred over a full match). For this reason, these items now
772        give a partial match in this situation. [Aside: previously, the one case
773        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
774        match rather than a full match, which was wrong by the old rules, but is
775        now correct.]
777    6.  There was a bug in the handling of #-introduced comments, recognized when
778        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
779        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
780        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
781        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
782        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
783        places in pcre_compile().
785    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
786        comments when looking ahead for named forward references to subpatterns,
787        the only newline sequence it recognized was NL. It now handles newlines
788        according to the set newline convention.
790    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
791        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
792        cater for a lack of strerror(). These oversights have been fixed.
794    9.  Added --match-limit and --recursion-limit to pcregrep.
796    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
798    11. When the -o option was used, pcregrep was setting a return code of 1, even
799        when matches were found, and --line-buffered was not being honoured.
801    12. Added an optional parentheses number to the -o and --only-matching options
802        of pcregrep.
804    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
805        can match an empty string. The code to do it in pcretest and pcredemo
806        needed fixing:
808        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
809            only one byte after an empty string match just before CRLF (this case
810            just got forgotten; "any" and "anycrlf" were OK).
812        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
813            mode when an empty string match preceded an ASCII character followed by
814            a non-ASCII character. (The code for advancing by one character rather
815            than one byte was nonsense.)
817        (c) The pcredemo.c sample program did not have any code at all to handle
818            the cases when CRLF is a valid newline sequence.
820    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
821        as a starting offset was within the subject string. There is now a new
822        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
823        negative or greater than the length of the string. In order to test this,
824        pcretest is extended to allow the setting of negative starting offsets.
826    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
827        starting offset points to the beginning of a UTF-8 character was
828        unnecessarily clumsy. I tidied it up.
830    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
831        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
833    17. Nobody had reported that the --include_dir option, which was added in
834        release 7.7 should have been called --include-dir (hyphen, not underscore)
835        for compatibility with GNU grep. I have changed it to --include-dir, but
836        left --include_dir as an undocumented synonym, and the same for
837        --exclude-dir, though that is not available in GNU grep, at least as of
838        release 2.5.4.
840    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
841        characters from a string of bytes) have been redefined so as not to use
842        loops, in order to improve performance in some environments. At the same
843        time, I abstracted some of the common code into auxiliary macros to save
844        repetition (this should not affect the compiled code).
846    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
847        compile-time error is now given if \c is not followed by an ASCII
848        character, that is, a byte less than 128. (In EBCDIC mode, the code is
849        different, and any byte value is allowed.)
851    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
852        START_OPTIMIZE option, which is now allowed at compile time - but just
853        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
854        to pcregrep and other applications that have no direct access to PCRE
855        options. The new /Y option in pcretest sets this option when calling
856        pcre_compile().
858    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
859        back references. Groups containing recursive back references were forced to
860        be atomic by that change, but in the case of named groups, the amount of
861        memory required was incorrectly computed, leading to "Failed: internal
862        error: code overflow". This has been fixed.
864    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
865        pcretest.c, to avoid build problems in some Borland environments.
868    Version 8.10 25-Jun-2010
869    ------------------------
871    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
872        THEN.
874    2.  (*ACCEPT) was not working when inside an atomic group.
876    3.  Inside a character class, \B is treated as a literal by default, but
877        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
878        causes the error). The code is unchanged, but I tidied the documentation.
880    4.  Inside a character class, PCRE always treated \R and \X as literals,
881        whereas Perl faults them if its -w option is set. I have changed PCRE so
882        that it faults them when PCRE_EXTRA is set.
884    5.  Added support for \N, which always matches any character other than
885        newline. (It is the same as "." when PCRE_DOTALL is not set.)
887    6.  When compiling pcregrep with newer versions of gcc which may have
888        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
889        declared with attribute warn_unused_result" were given. Just casting the
890        result to (void) does not stop the warnings; a more elaborate fudge is
891        needed. I've used a macro to implement this.
893    7.  Minor change to pcretest.c to avoid a compiler warning.
895    8.  Added four artifical Unicode properties to help with an option to make
896        \s etc use properties (see next item). The new properties are: Xan
897        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
899    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
900        use Unicode properties. (*UCP) at the start of a pattern can be used to set
901        this option. Modified pcretest to add /W to test this facility. Added
902        REG_UCP to make it available via the POSIX interface.
904    10. Added --line-buffered to pcregrep.
906    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
907        studied, and the match started with a letter with a code point greater than
908        127 whose first byte was different to the first byte of the other case of
909        the letter, the other case of this starting letter was not recognized
910        (#976).
912    12. If a pattern that was studied started with a repeated Unicode property
913        test, for example, \p{Nd}+, there was the theoretical possibility of
914        setting up an incorrect bitmap of starting bytes, but fortunately it could
915        not have actually happened in practice until change 8 above was made (it
916        added property types that matched character-matching opcodes).
918    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
919        possible starting bytes for non-anchored patterns.
921    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
922        \R, and also a number of cases that involve Unicode properties, both
923        explicit and implicit when PCRE_UCP is set.
925    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
926        input, it could crash or give wrong results if characters with values
927        greater than 0xc0 were present in the subject string. (Detail: it assumed
928        UTF-8 input when processing these items.)
930    16. Added a lot of (int) casts to avoid compiler warnings in systems where
931        size_t is 64-bit (#991).
933    17. Added a check for running out of memory when PCRE is compiled with
934        --disable-stack-for-recursion (#990).
936    18. If the last data line in a file for pcretest does not have a newline on
937        the end, a newline was missing in the output.
939    19. The default pcre_chartables.c file recognizes only ASCII characters (values
940        less than 128) in its various bitmaps. However, there is a facility for
941        generating tables according to the current locale when PCRE is compiled. It
942        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
943        characters, are recognized by isspace() and therefore were getting set in
944        these tables, and indeed these tables seem to approximate to ISO 8859. This
945        caused a problem in UTF-8 mode when pcre_study() was used to create a list
946        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
947        which of course cannot start UTF-8 characters. I have changed the code so
948        that only real ASCII characters (less than 128) and the correct starting
949        bytes for UTF-8 encodings are set for characters greater than 127 when in
950        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
951        altogether.)
953    20. Added the /T option to pcretest so as to be able to run tests with non-
954        standard character tables, thus making it possible to include the tests
955        used for 19 above in the standard set of tests.
957    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
958        reference to a subpattern the other side of a comment that contains an
959        opening parenthesis caused either an internal compiling error, or a
960        reference to the wrong subpattern.
963    Version 8.02 19-Mar-2010
964    ------------------------
966    1.  The Unicode data tables have been updated to Unicode 5.2.0.
968    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
969        configured.
971    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
972        original author of that file, following a query about its status.
974    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
975        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
977    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
978        quantifier applied to a forward-referencing subroutine call, could compile
979        incorrect code or give the error "internal error: previously-checked
980        referenced subpattern not found".
982    6.  Both MS Visual Studio and Symbian OS have problems with initializing
983        variables to point to external functions. For these systems, therefore,
984        pcre_malloc etc. are now initialized to local functions that call the
985        relevant global functions.
987    7.  There were two entries missing in the vectors called coptable and poptable
988        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
989        I've fixed the data, and added a kludgy way of testing at compile time that
990        the lengths are correct (equal to the number of opcodes).
992    8.  Following on from 7, I added a similar kludge to check the length of the
993        eint vector in pcreposix.c.
995    9.  Error texts for pcre_compile() are held as one long string to avoid too
996        much relocation at load time. To find a text, the string is searched,
997        counting zeros. There was no check for running off the end of the string,
998        which could happen if a new error number was added without updating the
999        string.
1001    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1003    11. \K was not working if it appeared in an atomic group or in a group that
1004        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1005        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1006        the assertion is positive, but not if it is negative.
1008    12. Change 11 fortuitously reduced the size of the stack frame used in the
1009        "match()" function of pcre_exec.c by one pointer. Forthcoming
1010        implementation of support for (*MARK) will need an extra pointer on the
1011        stack; I have reserved it now, so that the stack frame size does not
1012        decrease.
1014    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1015        item in branch that calls a recursion is a subroutine call - as in the
1016        second branch in the above example - was incorrectly given the compile-
1017        time error "recursive call could loop indefinitely" because pcre_compile()
1018        was not correctly checking the subroutine for matching a non-empty string.
1020    14. The checks for overrunning compiling workspace could trigger after an
1021        overrun had occurred. This is a "should never occur" error, but it can be
1022        triggered by pathological patterns such as hundreds of nested parentheses.
1023        The checks now trigger 100 bytes before the end of the workspace.
1025    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1028    Version 8.01 19-Jan-2010
1029    ------------------------
1031    1.  If a pattern contained a conditional subpattern with only one branch (in
1032        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1033        computed the wrong minimum data length (which is of course zero for such
1034        subpatterns). This could cause incorrect "no match" results.
1036    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1037        the pattern is reset in the first branch, pcre_compile() failed with
1038        "internal error: code overflow at offset...". This happened only when
1039        the reset was to the original external option setting. (An optimization
1040        abstracts leading options settings into an external setting, which was the
1041        cause of this.)
1043    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1044        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1045        assertion pattern did not match (meaning that the assertion was true), it
1046        was incorrectly treated as false if the SKIP had been reached during the
1047        matching. This also applied to assertions used as conditions.
1049    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1050        assertion subpattern, including such a pattern used as a condition,
1051        unpredictable results occurred, instead of the error return
1054    5.  The C++ GlobalReplace function was not working like Perl for the special
1055        situation when an empty string is matched. It now does the fancy magic
1056        stuff that is necessary.
1058    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1059        removed. (These were left over from very, very early versions of PCRE.)
1061    7.  Some cosmetic changes to the code to make life easier when compiling it
1062        as part of something else:
1064        (a) Change DEBUG to PCRE_DEBUG.
1066        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1067            called "current" as "current_branch", to prevent a collision with the
1068            Linux macro when compiled as a kernel module.
1070        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1071            prevent a collision with the Linux macro when compiled as a kernel
1072            module.
1074    8.  In pcre_compile() there are some checks for integer overflows that used to
1075        cast potentially large values to (double). This has been changed to that
1076        when building, a check for int64_t is made, and if it is found, it is used
1077        instead, thus avoiding the use of floating point arithmetic. (There is no
1078        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1079        double.
1081    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1082        2005 (difference between two addresses compared to an unsigned value).
1084    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1085        custom one, because of the following reported problem in Windows:
1087          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1088              under Win32.
1089          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1090              therefore missing the function definition.
1091          - The compiler thus generates a "C" signature for the test function.
1092          - The linker fails to find the "C" function.
1093          - PCRE fails to configure if asked to do so against libbz2.
1095    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1096        messages were output:
1098          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1099          rerunning libtoolize, to keep the correct libtool macros in-tree.
1100          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1102        I have done both of these things.
1104    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1105        most of the time, it *can* run out if it is given a pattern that contains a
1106        runaway infinite recursion. I updated the discussion in the pcrestack man
1107        page.
1109    13. Now that we have gone to the x.xx style of version numbers, the minor
1110        version may start with zero. Using 08 or 09 is a bad idea because users
1111        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1112        interpreted as invalid octal numbers. I've updated the previous comment in
1113        configure.ac, and also added a check that gives an error if 08 or 09 are
1114        used.
1116    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1117        causing partial matching to fail when the end of the subject matched \W
1118        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1120    15. There were some discrepancies between the declarations in pcre_internal.h
1121        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1122        their definitions. The declarations used "const uschar *" and the
1123        definitions used USPTR. Even though USPTR is normally defined as "const
1124        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1125        reported that: "This difference in casting confuses some C++ compilers, for
1126        example, SunCC recognizes above declarations as different functions and
1127        generates broken code for hbpcre." I have changed the declarations to use
1128        USPTR.
1130    16. GNU libtool is named differently on some systems. The autogen.sh script now
1131        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1132        (FreeBSD).
1134    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1135        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1136        comment: "Figure out how to create a longlong from a string: strtoll and
1137        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1138        instance, but it only takes 2 args instead of 3!"
1140    18. A subtle bug concerned with back references has been fixed by a change of
1141        specification, with a corresponding code fix. A pattern such as
1142        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1143        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1144        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1145        same bug. Such groups have to be quantified to be useful, or contained
1146        inside another quantified group. (If there's no repetition, the reference
1147        can never match.) The problem arises because, having left the group and
1148        moved on to the rest of the pattern, a later failure that backtracks into
1149        the group uses the captured value from the final iteration of the group
1150        rather than the correct earlier one. I have fixed this in PCRE by forcing
1151        any group that contains a reference to itself to be an atomic group; that
1152        is, there cannot be any backtracking into it once it has completed. This is
1153        similar to recursive and subroutine calls.
1156    Version 8.00 19-Oct-09
1157    ----------------------
1159    1.  The table for translating pcre_compile() error codes into POSIX error codes
1160        was out-of-date, and there was no check on the pcre_compile() error code
1161        being within the table. This could lead to an OK return being given in
1162        error.
1164    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1165        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1166        in a Windows environment.
1168    3.  The pcregrep --count option prints the count for each file even when it is
1169        zero, as does GNU grep. However, pcregrep was also printing all files when
1170        --files-with-matches was added. Now, when both options are given, it prints
1171        counts only for those files that have at least one match. (GNU grep just
1172        prints the file name in this circumstance, but including the count seems
1173        more useful - otherwise, why use --count?) Also ensured that the
1174        combination -clh just lists non-zero counts, with no names.
1176    4.  The long form of the pcregrep -F option was incorrectly implemented as
1177        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1178        but it seems right to fix it, and I didn't think it was worth preserving
1179        the old behaviour.
1181    5.  The command line items --regex=pattern and --regexp=pattern were not
1182        recognized by pcregrep, which required --regex pattern or --regexp pattern
1183        (with a space rather than an '='). The man page documented the '=' forms,
1184        which are compatible with GNU grep; these now work.
1186    6.  No libpcreposix.pc file was created for pkg-config; there was just
1187        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1189    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1190        when UCP support is not needed, by modifying the Python script that
1191        generates it from Unicode data files. This should not matter if the module
1192        is correctly used as a library, but I received one complaint about 50K of
1193        unwanted data. My guess is that the person linked everything into his
1194        program rather than using a library. Anyway, it does no harm.
1196    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1197        was a minimum greater than 1 for a wide character in a possessive
1198        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1199        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1200        character. Chaos in the form of incorrect output or a compiling loop could
1201        result.
1203    9.  The restrictions on what a pattern can contain when partial matching is
1204        requested for pcre_exec() have been removed. All patterns can now be
1205        partially matched by this function. In addition, if there are at least two
1206        slots in the offset vector, the offset of the earliest inspected character
1207        for the match and the offset of the end of the subject are set in them when
1208        PCRE_ERROR_PARTIAL is returned.
1210    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1211        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1212        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1213        and may be more useful for multi-segment matching.
1215    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1216        used to be given if ever the end of the subject was reached; now it is
1217        given only if matching could not proceed because another character was
1218        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1219        string "Z", which now yields "no match" instead of "partial match". In the
1220        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1221        final character ended with (*FAIL).
1223    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1224        if the pattern had a "must contain" character that was already found in the
1225        earlier partial match, unless partial matching was again requested. For
1226        example, with the pattern /dog.(body)?/, the "must contain" character is
1227        "g". If the first part-match was for the string "dog", restarting with
1228        "sbody" failed. This bug has been fixed.
1230    13. The string returned by pcre_dfa_exec() after a partial match has been
1231        changed so that it starts at the first inspected character rather than the
1232        first character of the match. This makes a difference only if the pattern
1233        starts with a lookbehind assertion or \b or \B (\K is not supported by
1234        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1235        matching functions compatible, and I think it's the right thing to do.
1237    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1238        so that the demonstration program is easily available in environments where
1239        PCRE has not been installed from source.
1241    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1242        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1243        library.
1245    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1246        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1247        is not the first non-POSIX option to be added. Clearly some people find
1248        these options useful.
1250    17. If a caller to the POSIX matching function regexec() passes a non-zero
1251        value for nmatch with a NULL value for pmatch, the value of
1252        nmatch is forced to zero.
1254    18. RunGrepTest did not have a test for the availability of the -u option of
1255        the diff command, as RunTest does. It now checks in the same way as
1256        RunTest, and also checks for the -b option.
1258    19. If an odd number of negated classes containing just a single character
1259        interposed, within parentheses, between a forward reference to a named
1260        subpattern and the definition of the subpattern, compilation crashed with
1261        an internal error, complaining that it could not find the referenced
1262        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1263        [The bug was that it was starting one character too far in when skipping
1264        over the character class, thus treating the ] as data rather than
1265        terminating the class. This meant it could skip too much.]
1267    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1268        /g option in pcretest when the pattern contains \K, which makes it possible
1269        to have an empty string match not at the start, even when the pattern is
1270        anchored. Updated pcretest and pcredemo to use this option.
1272    21. If the maximum number of capturing subpatterns in a recursion was greater
1273        than the maximum at the outer level, the higher number was returned, but
1274        with unset values at the outer level. The correct (outer level) value is
1275        now given.
1277    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1278        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1279        make it do so. The string so far is captured, making this feature
1280        compatible with Perl.
1282    23. The tests have been re-organized, adding tests 11 and 12, to make it
1283        possible to check the Perl 5.10 features against Perl 5.10.
1285    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1286        pattern matches a fixed length string. PCRE did not allow this; now it
1287        does. Neither allows recursion.
1289    25. I finally figured out how to implement a request to provide the minimum
1290        length of subject string that was needed in order to match a given pattern.
1291        (It was back references and recursion that I had previously got hung up
1292        on.) This code has now been added to pcre_study(); it finds a lower bound
1293        to the length of subject needed. It is not necessarily the greatest lower
1294        bound, but using it to avoid searching strings that are too short does give
1295        some useful speed-ups. The value is available to calling programs via
1296        pcre_fullinfo().
1298    26. While implementing 25, I discovered to my embarrassment that pcretest had
1299        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1300        study optimizations had never been tested with that matching function.
1301        Oops. What is worse, even when it was passed study data, there was a bug in
1302        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1303        were also very few tests of studied patterns with pcre_dfa_exec().
1305    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1306        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1307        on the other side of the coin, they are no longer allowed to have different
1308        names, because these cannot be distinguished in PCRE, and this has caused
1309        confusion. (This is a difference from Perl.)
1311    28. When duplicate subpattern names are present (necessarily with different
1312        numbers, as required by 27 above), and a test is made by name in a
1313        conditional pattern, either for a subpattern having been matched, or for
1314        recursion in such a pattern, all the associated numbered subpatterns are
1315        tested, and the overall condition is true if the condition is true for any
1316        one of them. This is the way Perl works, and is also more like the way
1317        testing by number works.
1320    Version 7.9 11-Apr-09
1321    ---------------------
1323    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1324        (pcretest), all targets were linked against these libraries. This included
1325        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1326        libraries. This caused unwanted dependencies to be created. This problem
1327        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1328        pcretest is linked with readline.
1330    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1331        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1332        moved outside it again, because FALSE and TRUE are already defined in AIX,
1333        but BOOL is not.
1335    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1336        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1338    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1339        hyphens) following file names and line numbers when outputting matching
1340        lines. This is not true; no spaces are inserted. I have also clarified the
1341        wording for the --colour (or --color) option.
1343    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1344        was not coloured; this is different to GNU grep, so I have changed it to be
1345        the same.
1347    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1348        each matching line was coloured. Now it goes on to look for further matches
1349        of any of the test patterns, which is the same behaviour as GNU grep.
1351    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1352        doesn't make sense to accept an empty string match in pcregrep, so I have
1353        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1354        seems to be how GNU grep behaves.
1356    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1357        start or after a newline", because the conditional assertion was not being
1358        correctly handled. The rule now is that both the assertion and what follows
1359        in the first alternative must satisfy the test.
1361    9.  If auto-callout was enabled in a pattern with a conditional group whose
1362        condition was an assertion, PCRE could crash during matching, both with
1363        pcre_exec() and pcre_dfa_exec().
1365    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1366        used for matching.
1368    11. Unicode property support in character classes was not working for
1369        characters (bytes) greater than 127 when not in UTF-8 mode.
1371    12. Added the -M command line option to pcretest.
1373    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1375    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1377    16. Added comments and documentation about mis-use of no_arg in the C++
1378        wrapper.
1380    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1381        from Martin Jerabek that uses macro names for all relevant character and
1382        string constants.
1384    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1385        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1386        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1387        these, but not everybody uses configure.
1389    19. A conditional group that had only one branch was not being correctly
1390        recognized as an item that could match an empty string. This meant that an
1391        enclosing group might also not be so recognized, causing infinite looping
1392        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1393        with the subject "ab", where knowledge that the repeated group can match
1394        nothing is needed in order to break the loop.
1396    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1397        exec(), but without supplying a callout function, matching went wrong.
1399    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1400        leak if the size of the offset vector was greater than 30. When the vector
1401        is smaller, the saved offsets during recursion go onto a local stack
1402        vector, but for larger vectors malloc() is used. It was failing to free
1403        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1404        error, in fact).
1406    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1407        heapframe that is used only when UTF-8 support is enabled. This caused no
1408        problem, but was untidy.
1410    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1411        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1412        included within another project.
1414    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1415        slightly modified by me:
1417          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1418              not building pcregrep.
1420          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1421              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1423    25. Forward references, both numeric and by name, in patterns that made use of
1424        duplicate group numbers, could behave incorrectly or give incorrect errors,
1425        because when scanning forward to find the reference group, PCRE was not
1426        taking into account the duplicate group numbers. A pattern such as
1427        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1429    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1430        the feature of a custom pointer more persuasive (as requested by a user).
1432    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1433        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1434        pre-defined.
1436    28. Added support for (*UTF8) at the start of a pattern.
1438    29. Arrange for flags added by the "release type" setting in CMake to be shown
1439        in the configuration summary.
1442    Version 7.8 05-Sep-08
1443    ---------------------
1445    1.  Replaced UCP searching code with optimized version as implemented for Ad
1446        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1447        stage table and inline lookup instead of a function, giving speed ups of 2
1448        to 5 times on some simple patterns that I tested. Permission was given to
1449        distribute the MultiStage2.py script that generates the tables (it's not in
1450        the tarball, but is in the Subversion repository).
1452    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1453        scripts.
1455    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1456        a group with a zero qualifier. The result of the study could be incorrect,
1457        or the function might crash, depending on the pattern.
1459    4.  Caseless matching was not working for non-ASCII characters in back
1460        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1461        It now works when Unicode Property Support is available.
1463    5.  In pcretest, an escape such as \x{de} in the data was always generating
1464        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1465        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1466        truncation.
1468    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1470    7.  Added two (int) casts to pcregrep when printing the difference of two
1471        pointers, in case they are 64-bit values.
1473    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1474        test 2 if it fails.
1476    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1477        and a #define of that name to empty if it is not externally set. This is to
1478        allow users of MSVC to set it if necessary.
1480    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1481        the convenience functions in the pcre_get.c source file.
1483    11. An option change at the start of a pattern that had top-level alternatives
1484        could cause overwriting and/or a crash. This command provoked a crash in
1485        some environments:
1487          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1489        This potential security problem was recorded as CVE-2008-2371.
1491    12. For a pattern where the match had to start at the beginning or immediately
1492        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1493        pcre_dfa_exec() could read past the end of the passed subject if there was
1494        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1495        pcretest so that it places the subject at the end of its malloc-ed buffer.
1497    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1498        exec() might read past the end of the data buffer in UTF-8 mode.
1500    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1501        the data contained the byte 0x85 as part of a UTF-8 character within its
1502        first line. This applied both to normal and DFA matching.
1504    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1505        /^[^d]*?$/8 failed to match "abc".
1507    16. Added a missing copyright notice to pcrecpp_internal.h.
1509    17. Make it more clear in the documentation that values returned from
1510        pcre_exec() in ovector are byte offsets, not character counts.
1512    18. Tidied a few places to stop certain compilers from issuing warnings.
1514    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1515        supplied by Stefan Weber. I made a further small update for 7.8 because
1516        there is a change of source arrangements: the pcre_searchfuncs.c module is
1517        replaced by pcre_ucd.c.
1520    Version 7.7 07-May-08
1521    ---------------------
1523    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1524        a string to a long long, pretend we don't even have a long long." This is
1525        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1527    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1528        pre-7.6 versions, which defined a global no_arg variable instead of putting
1529        it in the RE class. (See also #8 below.)
1531    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1532        Lopes.
1534    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1536        (1) The include/exclude patterns were being applied to the whole pathnames
1537            of files, instead of just to the final components.
1539        (2) If there was more than one level of directory, the subdirectories were
1540            skipped unless they satisfied the include/exclude conditions. This is
1541            inconsistent with GNU grep (and could even be seen as contrary to the
1542            pcregrep specification - which I improved to make it absolutely clear).
1543            The action now is always to scan all levels of directory, and just
1544            apply the include/exclude patterns to regular files.
1546    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1547        --exclude_dir in the tests to avoid scanning .svn directories.
1549    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1550        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1551        doesn't support NULs in patterns.
1553    7.  Added some missing "const"s to declarations of static tables in
1554        pcre_compile.c and pcre_dfa_exec.c.
1556    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1557        caused by fix #2  above. (Subsequently also a second patch to fix the
1558        first patch. And a third patch - this was a messy problem.)
1560    9.  Applied Craig's patch to remove the use of push_back().
1562    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1563        matching function regexec().
1565    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1566        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1567        references. PCRE supports relative numbers with this syntax (I don't think
1568        Oniguruma does).
1570    12. Previously, a group with a zero repeat such as (...){0} was completely
1571        omitted from the compiled regex. However, this means that if the group
1572        was called as a subroutine from elsewhere in the pattern, things went wrong
1573        (an internal error was given). Such groups are now left in the compiled
1574        pattern, with a new opcode that causes them to be skipped at execution
1575        time.
1577    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1578        to the way PCRE behaves:
1580        (a) A lone ] character is dis-allowed (Perl treats it as data).
1582        (b) A back reference to an unmatched subpattern matches an empty string
1583            (Perl fails the current match path).
1585        (c) A data ] in a character class must be notated as \] because if the
1586            first data character in a class is ], it defines an empty class. (In
1587            Perl it is not possible to have an empty class.) The empty class []
1588            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1589            The negative empty class [^] matches any one character, independently
1590            of the DOTALL setting.
1592    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1593        non-existent subpattern following a character class starting with ']' and
1594        containing () gave an internal compiling error instead of "reference to
1595        non-existent subpattern". Fortunately, when the pattern did exist, the
1596        compiled code was correct. (When scanning forwards to check for the
1597        existencd of the subpattern, it was treating the data ']' as terminating
1598        the class, so got the count wrong. When actually compiling, the reference
1599        was subsequently set up correctly.)
1601    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1602        it was being rejected as not supported by pcre_dfa_exec(), even though
1603        other assertions are supported. I have made pcre_dfa_exec() support
1604        (*FAIL).
1606    16. The implementation of 13c above involved the invention of a new opcode,
1607        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1608        cannot be changed at match time, I realized I could make a small
1609        improvement to matching performance by compiling OP_ALLANY instead of
1610        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1611        on the OP_ANY path.
1613    17. Compiling pcretest on Windows with readline support failed without the
1614        following two fixes: (1) Make the unistd.h include conditional on
1615        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1617    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1618        ncurses library to be included for pcretest when ReadLine support is
1619        requested, but also to allow for it to be overridden. This patch came from
1620        Daniel Bergström.
1622    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1623        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1624        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1625        spotting this.
1628    Version 7.6 28-Jan-08
1629    ---------------------
1631    1.  A character class containing a very large number of characters with
1632        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1633        overflow.
1635    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1636        HAVE_LONG_LONG is not defined.
1638    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1639        bring them up to date and include new features. This patch includes:
1641        - Fixed PH's badly added libz and libbz2 support.
1642        - Fixed a problem with static linking.
1643        - Added pcredemo. [But later removed - see 7 below.]
1644        - Fixed dftables problem and added an option.
1645        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1646            HAVE_LONG_LONG.
1647        - Added readline support for pcretest.
1648        - Added an listing of the option settings after cmake has run.
1650    4.  A user submitted a patch to Makefile that makes it easy to create
1651        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1652        Makefile.am that cause it to include this special target, without
1653        affecting anything else. Note that the same mingw target plus all
1654        the other distribution libraries and programs are now supported
1655        when configuring with CMake (see 6 below) instead of with
1656        Configure/Make.
1658    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1659        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1660        exported in the Windows port". It has not yet been confirmed that the patch
1661        solves the problem, but it does no harm.
1663    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1664        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1665        with CMake, and also correct the comment about stack recursion.
1667    7.  Remove the automatic building of pcredemo from the ./configure system and
1668        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1669        of a program that users should build themselves after PCRE is installed, so
1670        building it automatically is not really right. What is more, it gave
1671        trouble in some build environments.
1673    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1676    Version 7.5 10-Jan-08
1677    ---------------------
1679    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1680        values in parens when parsing an RE using the C++ wrapper."
1682    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1683        Characters greater than 255 were excluded from the class instead of being
1684        included.
1686    3.  The same bug as (2) above applied to negated POSIX classes such as
1687        [:^space:].
1689    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1690        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1691        I have changed it.
1693    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1694        first named subpattern) and a construct such as (?&a) would reference the
1695        first named subpattern whose name started with "a" (in other words, the
1696        length check was missing). Both these problems are fixed. "Subpattern name
1697        expected" is now given for (?&) (a zero-length name), and this patch also
1698        makes it give the same error for \k'' (previously it complained that that
1699        was a reference to a non-existent subpattern).
1701    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1702        this is right because (?- can be followed by option settings as well as by
1703        digits. I have, however, made the messages clearer.
1705    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1706        than the number used in the conditional) now cause a compile-time error.
1707        This is actually not compatible with Perl, which accepts such patterns, but
1708        treats the conditional as always being FALSE (as PCRE used to), but it
1709        seems to me that giving a diagnostic is better.
1711    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1712        and messages.
1714    9.  Fix two occurrences of "backslash" in comments that should have been
1715        "backspace".
1717    10. Remove two redundant lines of code that can never be obeyed (their function
1718        was moved elsewhere).
1720    11. The program that makes PCRE's Unicode character property table had a bug
1721        which caused it to generate incorrect table entries for sequences of
1722        characters that have the same character type, but are in different scripts.
1723        It amalgamated them into a single range, with the script of the first of
1724        them. In other words, some characters were in the wrong script. There were
1725        thirteen such cases, affecting characters in the following ranges:
1727          U+002b0 - U+002c1
1728          U+0060c - U+0060d
1729          U+0061e - U+00612
1730          U+0064b - U+0065e
1731          U+0074d - U+0076d
1732          U+01800 - U+01805
1733          U+01d00 - U+01d77
1734          U+01d9b - U+01dbf
1735          U+0200b - U+0200f
1736          U+030fc - U+030fe
1737          U+03260 - U+0327f
1738          U+0fb46 - U+0fbb1
1739          U+10450 - U+1049d
1741    12. The -o option (show only the matching part of a line) for pcregrep was not
1742        compatible with GNU grep in that, if there was more than one match in a
1743        line, it showed only the first of them. It now behaves in the same way as
1744        GNU grep.
1746    13. If the -o and -v options were combined for pcregrep, it printed a blank
1747        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1748        does the same. The return code can be used to tell if there were any
1749        non-matching lines.
1751    14. Added --file-offsets and --line-offsets to pcregrep.
1753    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1754        infinitely looping recursion. The bug was that positive lookaheads were not
1755        being skipped when checking for a possible empty match (negative lookaheads
1756        and both kinds of lookbehind were skipped).
1758    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1759        inclusion of <windows.h> to before rather than after the definition of
1760        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1762    17. Specifying a possessive quantifier with a specific limit for a Unicode
1763        character property caused pcre_compile() to compile bad code, which led at
1764        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1765        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1766        caused the error; without that there was no problem.
1768    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1770    19. Added --enable-pcretest-libreadline.
1772    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1773        RE::GlobalReplace(). As a result, the number of replacements returned was
1774        double what it should be. I removed one of the increments, but Craig sent a
1775        later patch that removed the other one (the right fix) and added unit tests
1776        that check the return values (which was not done before).
1778    21. Several CMake things:
1780        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1781            the names libpcre and libpcreposix, not just pcre and pcreposix.
1783        (2) The above change means that pcretest and pcregrep are now correctly
1784            linked with the newly-built libraries, not previously installed ones.
1788    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1789        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1790        UTF-8 newline character). The key issue is that the pattern starts .*;
1791        this means that the match must be either at the beginning, or after a
1792        newline. The bug was in the code for advancing after a failed match and
1793        checking that the new position followed a newline. It was not taking
1794        account of UTF-8 characters correctly.
1796    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1797        character classes. PCRE was not treating the sequence [:...:] as a
1798        character class unless the ... were all letters. Perl, however, seems to
1799        allow any characters between [: and :], though of course it rejects as
1800        unknown any "names" that contain non-letters, because all the known class
1801        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1802        for example, whereas PCRE did not - it did not recognize a POSIX character
1803        class. This seemed a bit dangerous, so the code has been changed to be
1804        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1805        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1806        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1807        Perl does, and where it didn't before.
1809    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1810        Windows environments %n is disabled by default.
1813    Version 7.4 21-Sep-07
1814    ---------------------
1816    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1817        means that a class such as [\s] counted as "explicit reference to CR or
1818        LF". That isn't really right - the whole point of the change was to try to
1819        help when there was an actual mention of one of the two characters. So now
1820        the change happens only if \r or \n (or a literal CR or LF) character is
1821        encountered.
1823    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1824        of both had grown to the point where there were only 3 bits left.
1825        Fortunately, there was spare space in the data structure, and so I have
1826        moved the internal flags into a new 16-bit field to free up more option
1827        bits.
1829    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1830        but did not set the internal JCHANGED flag - either of these is enough to
1831        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1832        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1833        start sets both bits.
1835    4.  Added options (at build time, compile time, exec time) to change \R from
1836        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1838    5.  doc/pcresyntax.html was missing from the distribution.
1840    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1841        compatibility, even though it is no longer used.
1843    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1844        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1845        windows.h file is present (where different names are used). [This was
1846        reversed later after testing - see 16 below.]
1848    8.  Changed all #include <config.h> to #include "config.h". There were also
1849        some further <pcre.h> cases that I changed to "pcre.h".
1851    9.  When pcregrep was used with the --colour option, it missed the line ending
1852        sequence off the lines that it output.
1854    10. It was pointed out to me that arrays of string pointers cause lots of
1855        relocations when a shared library is dynamically loaded. A technique of
1856        using a single long string with a table of offsets can drastically reduce
1857        these. I have refactored PCRE in four places to do this. The result is
1858        dramatic:
1860          Originally:                          290
1861          After changing UCP table:            187
1862          After changing error message table:   43
1863          After changing table of "verbs"       36
1864          After changing table of Posix names   22
1866        Thanks to the folks working on Gregex for glib for this insight.
1868    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1869        unicode-properties was also set.
1871    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1873    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1874        checked only for CRLF.
1876    14. Added casts to pcretest.c to avoid compiler warnings.
1878    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1880    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1881        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1882        entirely. This removes changes made in 7 above.
1884    17. The CMake files have been updated, and there is now more information about
1885        building with CMake in the NON-UNIX-USE document.
1888    Version 7.3 28-Aug-07
1889    ---------------------
1891     1. In the rejigging of the build system that eventually resulted in 7.1, the
1892        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1893        brackets there is not right, since it causes compilers to look for an
1894        installed pcre.h, not the version that is in the source that is being
1895        compiled (which of course may be different). I have changed it back to:
1897          #include "pcre.h"
1899        I have a vague recollection that the change was concerned with compiling in
1900        different directories, but in the new build system, that is taken care of
1901        by the VPATH setting the Makefile.
1903     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1904        when the subject happened to end in the byte 0x85 (e.g. if the last
1905        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1906        characters but of course it shouldn't be taken as a newline when it is part
1907        of another character. The bug was that, for an unlimited repeat of . in
1908        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1909        characters when looking for a newline.
1911     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1913     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1914        in debug output.
1916     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1917        long printing in the pcrecpp unittest when running under MinGW.
1919     6. ESC_K was left out of the EBCDIC table.
1921     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1922        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1923        limit also applies to "virtual nesting" when a pattern is recursive, and in
1924        this case 1000 isn't so big. I have been able to remove this limit at the
1925        expense of backing off one optimization in certain circumstances. Normally,
1926        when pcre_exec() would call its internal match() function recursively and
1927        immediately return the result unconditionally, it uses a "tail recursion"
1928        feature to save stack. However, when a subpattern that can match an empty
1929        string has an unlimited repetition quantifier, it no longer makes this
1930        optimization. That gives it a stack frame in which to save the data for
1931        checking that an empty string has been matched. Previously this was taken
1932        from the 1000-entry workspace that had been reserved. So now there is no
1933        explicit limit, but more stack is used.
1935     8. Applied Daniel's patches to solve problems with the import/export magic
1936        syntax that is required for Windows, and which was going wrong for the
1937        pcreposix and pcrecpp parts of the library. These were overlooked when this
1938        problem was solved for the main library.
1940     9. There were some crude static tests to avoid integer overflow when computing
1941        the size of patterns that contain repeated groups with explicit upper
1942        limits. As the maximum quantifier is 65535, the maximum group length was
1943        set at 30,000 so that the product of these two numbers did not overflow a
1944        32-bit integer. However, it turns out that people want to use groups that
1945        are longer than 30,000 bytes (though not repeat them that many times).
1946        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1947        made it possible to implement the integer overflow checks in a much more
1948        dynamic way, which I have now done. The artificial limitation on group
1949        length has been removed - we now have only the limit on the total length of
1950        the compiled pattern, which depends on the LINK_SIZE setting.
1952    10. Fixed a bug in the documentation for get/copy named substring when
1953        duplicate names are permitted. If none of the named substrings are set, the
1954        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1955        empty string.
1957    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1958        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1959        because the ] is interpreted as the first data character and the
1960        terminating ] is not found. PCRE has been made compatible with Perl in this
1961        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1962        cause memory overwriting.
1964    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1965        string has been matched (to stop an infinite loop). It was not recognizing
1966        a conditional subpattern that could match an empty string if that
1967        subpattern was within another subpattern. For example, it looped when
1968        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1969        condition was not nested. This bug has been fixed.
1971    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1972        past the start of the subject in the presence of bytes with the top bit
1973        set, for example "\x8aBCD".
1975    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1976        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1978    14. Optimized (?!) to (*FAIL).
1980    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1981        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1982        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1983        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1984        does: it's just the validity check that is more restrictive.
1986    16. Inserted checks for integer overflows during escape sequence (backslash)
1987        processing, and also fixed erroneous offset values for syntax errors during
1988        backslash processing.
1990    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1991        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1993    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1994        caused an overrun.
1996    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1997        something other than just ASCII characters) inside a group that had an
1998        unlimited repeat caused a loop at compile time (while checking to see
1999        whether the group could match an empty string).
2001    20. Debugging a pattern containing \p or \P could cause a crash. For example,
2002        [\P{Any}] did so. (Error in the code for printing property names.)
2004    21. An orphan \E inside a character class could cause a crash.
2006    22. A repeated capturing bracket such as (A)? could cause a wild memory
2007        reference during compilation.
2009    23. There are several functions in pcre_compile() that scan along a compiled
2010        expression for various reasons (e.g. to see if it's fixed length for look
2011        behind). There were bugs in these functions when a repeated \p or \P was
2012        present in the pattern. These operators have additional parameters compared
2013        with \d, etc, and these were not being taken into account when moving along
2014        the compiled data. Specifically:
2016        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
2017            length.
2019        (b) An item such as \pL+ within a repeated group could cause crashes or
2020            loops.
2022        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
2023            "reference to non-existent subpattern" error.
2025        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
2027    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
2028        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
2030    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
2032    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
2033        character were causing crashes (broken optimization).
2035    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
2036        \p or \P) caused a compile-time loop.
2038    28. More problems have arisen in unanchored patterns when CRLF is a valid line
2039        break. For example, the unstudied pattern [\r\n]A does not match the string
2040        "\r\nA" because change 7.0/46 below moves the current point on by two
2041        characters after failing to match at the start. However, the pattern \nA
2042        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
2043        the same is true. There doesn't seem any very clean way out of this, but
2044        what I have chosen to do makes the common cases work: PCRE now takes note
2045        of whether there can be an explicit match for \r or \n anywhere in the
2046        pattern, and if so, 7.0/46 no longer applies. As part of this change,
2047        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
2048        pattern has explicit CR or LF references.
2050    29. Added (*CR) etc for changing newline setting at start of pattern.
2053    Version 7.2 19-Jun-07
2054    ---------------------
2056     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
2057        which is apparently normally available under Windows.
2059     2. Re-jig the pcregrep tests with different newline settings in an attempt
2060        to make them independent of the local environment's newline setting.
2062     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
2064     4. Some of the "internals" tests were previously cut out when the link size
2065        was not 2, because the output contained actual offsets. The recent new
2066        "Z" feature of pcretest means that these can be cut out, making the tests
2067        usable with all link sizes.
2069     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
2070        stack recursion. This gives a massive performance boost under BSD, but just
2071        a small improvement under Linux. However, it saves one field in the frame
2072        in all cases.
2074     6. Added more features from the forthcoming Perl 5.10:
2076        (a) (?-n) (where n is a string of digits) is a relative subroutine or
2077            recursion call. It refers to the nth most recently opened parentheses.
2079        (b) (?+n) is also a relative subroutine call; it refers to the nth next
2080            to be opened parentheses.
2082        (c) Conditions that refer to capturing parentheses can be specified
2083            relatively, for example, (?(-2)... or (?(+3)...
2085        (d) \K resets the start of the current match so that everything before
2086            is not part of it.
2088        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
2090        (f) \g{name} is another synonym - part of Perl 5.10's unification of
2091            reference syntax.
2093        (g) (?| introduces a group in which the numbering of parentheses in each
2094            alternative starts with the same number.
2096        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
2098     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
2101     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
2102        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
2103        for detecting groups that can match an empty string.
2105     9. A pattern with a very large number of alternatives (more than several
2106        hundred) was running out of internal workspace during the pre-compile
2107        phase, where pcre_compile() figures out how much memory will be needed. A
2108        bit of new cunning has reduced the workspace needed for groups with
2109        alternatives. The 1000-alternative test pattern now uses 12 bytes of
2110        workspace instead of running out of the 4096 that are available.
2112    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
2114    11. Applied patch from Google to remove an optimization that didn't quite work.
2115        The report of the bug said:
2117          pcrecpp::RE("a*").FullMatch("aaa") matches, while
2118          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
2119          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
2121    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
2122        it matched the wrong number of bytes.
2125    Version 7.1 24-Apr-07
2126    ---------------------
2128     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
2129        that is more "standard", making use of automake and other Autotools. There
2130        is some re-arrangement of the files and adjustment of comments consequent
2131        on this.
2133     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2134        for recursive directory scanning broke on some systems because the files
2135        are not scanned in any specific order and on different systems the order
2136        was different. A call to "sort" has been inserted into RunGrepTest for the
2137        approprate test as a short-term fix. In the longer term there may be an
2138        alternative.
2140     3. I had an email from Eric Raymond about problems translating some of PCRE's
2141        man pages to HTML (despite the fact that I distribute HTML pages, some
2142        people do their own conversions for various reasons). The problems
2143        concerned the use of low-level troff macros .br and .in. I have therefore
2144        removed all such uses from the man pages (some were redundant, some could
2145        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2146        HTML has been updated to handle .nf/.fi and to complain if it encounters
2147        .br or .in.
2149     4. Updated comments in configure.ac that get placed in config.h.in and also
2150        arranged for config.h to be included in the distribution, with the name
2151        config.h.generic, for the benefit of those who have to compile without
2152        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2154     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2155        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2156        makevp.bat for the current PCRE, using the additional files
2157        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2159     6. A Windows user reported a minor discrepancy with test 2, which turned out
2160        to be caused by a trailing space on an input line that had got lost in his
2161        copy. The trailing space was an accident, so I've just removed it.
2163     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2164        that is needed.
2166     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2167        as "const" (a) because they are and (b) because it helps the PHP
2168        maintainers who have recently made a script to detect big data structures
2169        in the php code that should be moved to the .rodata section. I remembered
2170        to update Builducptable as well, so it won't revert if ucptable.h is ever
2171        re-created.
2173     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2174        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2175        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2176        support is not required. This saves 1.5-2K of code, which is important in
2177        some applications.
2179        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2180        so as not to refer to the tables, even though these functions will never be
2181        called when UTF-8 support is disabled. Otherwise there are problems with a
2182        shared library.
2184    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2186        (a) It was defining its arguments as char * instead of void *.
2188        (b) It was assuming that all moves were upwards in memory; this was true
2189            a long time ago when I wrote it, but is no longer the case.
2191        The emulated memove() is provided for those environments that have neither
2192        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2193        is clearly not the case, as these two bugs were recently reported.
2195    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2196        and Detrail to create the HTML documentation, the .txt form of the man
2197        pages, and it removes trailing spaces from listed files. It also creates
2198        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2199        case, it wraps all the #defines with #ifndefs. This script should be run
2200        before "make dist".
2202    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2203        with Unicode property support.
2205        (a) For a maximizing quantifier, if the two different cases of the
2206            character were of different lengths in their UTF-8 codings (there are
2207            some cases like this - I found 11), and the matching function had to
2208            back up over a mixture of the two cases, it incorrectly assumed they
2209            were both the same length.
2211        (b) When PCRE was configured to use the heap rather than the stack for
2212            recursion during matching, it was not correctly preserving the data for
2213            the other case of a UTF-8 character when checking ahead for a match
2214            while processing a minimizing repeat. If the check also involved
2215            matching a wide character, but failed, corruption could cause an
2216            erroneous result when trying to check for a repeat of the original
2217            character.
2219    13. Some tidying changes to the testing mechanism:
2221        (a) The RunTest script now detects the internal link size and whether there
2222            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2223            values substituted by "configure". (The RunGrepTest script already did
2224            this for UTF-8.) The configure.ac script no longer substitutes the
2225            relevant variables.
2227        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2228            with length and offset values. This means that the output is different
2229            for different internal link sizes. Test 2 is skipped for link sizes
2230            other than 2 because of this, bypassing the problem. Unfortunately,
2231            there was also a test in test 3 (the locale tests) that used /B and
2232            failed for link sizes other than 2. Rather than cut the whole test out,
2233            I have added a new /Z option to pcretest that replaces the length and
2234            offset values with spaces. This is now used to make test 3 independent
2235            of link size. (Test 2 will be tidied up later.)
2237    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2238        segmentation fault instead of returning the appropriate error message.
2240    15. In multiline mode when the newline sequence was set to "any", the pattern
2241        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2242        This doesn't seem right; it now treats the CRLF combination as the line
2243        ending, and so does not match in that case. It's only a pattern such as ^$
2244        that would hit this one: something like ^ABC$ would have failed after \r
2245        and then tried again after \r\n.
2247    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2248        in an attempt to make files that differ only in their line terminators
2249        compare equal. This works on Linux.
2251    17. Under certain error circumstances pcregrep might try to free random memory
2252        as it exited. This is now fixed, thanks to valgrind.
2254    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2255        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2256        was because its rules for how to advance for /g after matching an empty
2257        string at the end of a line did not allow for this case. They now check for
2258        it specially.
2260    20. pcretest is supposed to handle patterns and data of any length, by
2261        extending its buffers when necessary. It was getting this wrong when the
2262        buffer for a data line had to be extended.
2264    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2265        CRLF as a newline sequence.
2267    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2268        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2269        I have nevertheless tidied it up.
2271    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2273    24. Added a man page for pcre-config.
2276    Version 7.0 19-Dec-06
2277    ---------------------
2279     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2280        moving to gcc 4.1.1.
2282     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2283        sys/time.h, which is documented as needed for this function. It doesn't
2284        seem to matter on Linux, but it showed up on some releases of OS X.
2286     3. It seems that there are systems where bytes whose values are greater than
2287        127 match isprint() in the "C" locale. The "C" locale should be the
2288        default when a C program starts up. In most systems, only ASCII printing
2289        characters match isprint(). This difference caused the output from pcretest
2290        to vary, making some of the tests fail. I have changed pcretest so that:
2292        (a) When it is outputting text in the compiled version of a pattern, bytes
2293            other than 32-126 are always shown as hex escapes.
2295        (b) When it is outputting text that is a matched part of a subject string,
2296            it does the same, unless a different locale has been set for the match
2297            (using the /L modifier). In this case, it uses isprint() to decide.
2299     4. Fixed a major bug that caused incorrect computation of the amount of memory
2300        required for a compiled pattern when options that changed within the
2301        pattern affected the logic of the preliminary scan that determines the
2302        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2303        that the computed length was too small. The symptoms of this bug were
2304        either the PCRE error "internal error: code overflow" from pcre_compile(),
2305        or a glibc crash with a message such as "pcretest: free(): invalid next
2306        size (fast)". Examples of patterns that provoked this bug (shown in
2307        pcretest format) are:
2309          /(?-x: )/x
2310          /(?x)(?-x: \s*#\s*)/
2311          /((?i)[\x{c0}])/8
2312          /(?i:[\x{c0}])/8
2314        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2315        is now done differently.
2317     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2318        wrapper classes; (b) implement a new function in the C++ scanner that is
2319        more efficient than the old way of doing things because it avoids levels of
2320        recursion in the regex matching; (c) add a paragraph to the documentation
2321        for the FullMatch() function.
2323     6. The escape sequence \n was being treated as whatever was defined as
2324        "newline". Not only was this contrary to the documentation, which states
2325        that \n is character 10 (hex 0A), but it also went horribly wrong when
2326        "newline" was defined as CRLF. This has been fixed.
2328     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2329        was being set to -1 for the "end of line" case (supposedly a value that no
2330        character can have). Though this value is never used (the check for end of
2331        line is "zero bytes in current character"), it caused compiler complaints.
2332        I've changed it to 0xffffffff.
2334     8. In pcre_version.c, the version string was being built by a sequence of
2335        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2336        string (as it is for production releases) called a macro with an empty
2337        argument. The C standard says the result of this is undefined. The gcc
2338        compiler treats it as an empty string (which was what was wanted) but it is
2339        reported that Visual C gives an error. The source has been hacked around to
2340        avoid this problem.
2342     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2343        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2344        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2345        of them did).
2347    10. Originally, pcretest opened its input and output without "b"; then I was
2348        told that "b" was needed in some environments, so it was added for release
2349        5.0 to both the input and output. (It makes no difference on Unix-like
2350        systems.) Later I was told that it is wrong for the input on Windows. I've
2351        now abstracted the modes into two macros, to make it easier to fiddle with
2352        them, and removed "b" from the input mode under Windows.
2354    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2356    12. Added -help and --help to pcretest as an official way of being reminded
2357        of the options.
2359    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2360        and pcrecpp.cc because they annoy compilers at high warning levels.
2362    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2364    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2365        scripts are not C programs :-) and which was not noticed because it works
2366        on Linux.
2368    16. pcretest is supposed to handle any length of pattern and data line (as one
2369        line or as a continued sequence of lines) by extending its input buffer if
2370        necessary. This feature was broken for very long pattern lines, leading to
2371        a string of junk being passed to pcre_compile() if the pattern was longer
2372        than about 50K.
2374    17. I have done a major re-factoring of the way pcre_compile() computes the
2375        amount of memory needed for a compiled pattern. Previously, there was code
2376        that made a preliminary scan of the pattern in order to do this. That was
2377        OK when PCRE was new, but as the facilities have expanded, it has become
2378        harder and harder to keep it in step with the real compile phase, and there
2379        have been a number of bugs (see for example, 4 above). I have now found a
2380        cunning way of running the real compile function in a "fake" mode that
2381        enables it to compute how much memory it would need, while actually only
2382        ever using a few hundred bytes of working memory and without too many
2383        tests of the mode. This should make future maintenance and development
2384        easier. A side effect of this work is that the limit of 200 on the nesting
2385        depth of parentheses has been removed (though this was never a serious
2386        limitation, I suspect). However, there is a downside: pcre_compile() now
2387        runs more slowly than before (30% or more, depending on the pattern). I
2388        hope this isn't a big issue. There is no effect on runtime performance.
2390    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2391        newline (only possible for the last line of a file) and it was a
2392        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2394    19. Added additional timing features to pcretest. (1) The -tm option now times
2395        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2396        separate command line item, by a number that specifies the number of
2397        repeats to use when timing. The default is 50000; this gives better
2398        precision, but takes uncomfortably long for very large patterns.
2400    20. Extended pcre_study() to be more clever in cases where a branch of a
2401        subpattern has no definite first character. For example, (a*|b*)[cd] would
2402        previously give no result from pcre_study(). Now it recognizes that the
2403        first character must be a, b, c, or d.
2405    21. There was an incorrect error "recursive call could loop indefinitely" if
2406        a subpattern (or the entire pattern) that was being tested for matching an
2407        empty string contained only one non-empty item after a nested subpattern.
2408        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2409        incorrectly, because the \d was being skipped in the check.
2411    22. The pcretest program now has a new pattern option /B and a command line
2412        option -b, which is equivalent to adding /B to every pattern. This causes
2413        it to show the compiled bytecode, without the additional information that
2414        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2415        is the same as /B/I).
2417    23. A new optimization is now able automatically to treat some sequences such
2418        as a*b as a*+b. More specifically, if something simple (such as a character
2419        or a simple class like \d) has an unlimited quantifier, and is followed by
2420        something that cannot possibly match the quantified thing, the quantifier
2421        is automatically "possessified".
2423    24. A recursive reference to a subpattern whose number was greater than 39
2424        went wrong under certain circumstances in UTF-8 mode. This bug could also
2425        have affected the operation of pcre_study().
2427    25. Realized that a little bit of performance could be had by replacing
2428        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2430    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2432    27. Possessive quantifiers such as a++ were previously implemented by turning
2433        them into atomic groups such as ($>a+). Now they have their own opcodes,
2434        which improves performance. This includes the automatically created ones
2435        from 23 above.
2437    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2438        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2439        the first matched character to be a colon. This applied both to named and
2440        numbered groups.
2442    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2444    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2445        building PCRE on Windows easier, so I have included it in the distribution.
2447    31. There is now a check in pcretest against a ridiculously large number being
2448        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2449        loop, the loop is abandoned.
2451    32. Forward references to subpatterns in conditions such as (?(2)...) where
2452        subpattern 2 is defined later cause pcre_compile() to search forwards in
2453        the pattern for the relevant set of parentheses. This search went wrong
2454        when there were unescaped parentheses in a character class, parentheses
2455        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2457    33. "Subroutine" calls and backreferences were previously restricted to
2458        referencing subpatterns earlier in the regex. This restriction has now
2459        been removed.
2461    34. Added a number of extra features that are going to be in Perl 5.10. On the
2462        whole, these are just syntactic alternatives for features that PCRE had
2463        previously implemented using the Python syntax or my own invention. The
2464        other formats are all retained for compatibility.
2466        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2467            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2468            also .NET compatible.
2470        (b) A recursion or subroutine call to a named group can now be defined as
2471            (?&name) as well as (?P>name).
2473        (c) A backreference to a named group can now be defined as \k<name> or
2474            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2475            5.10, are also .NET compatible.
2477        (d) A conditional reference to a named group can now use the syntax
2478            (?(<name>) or (?('name') as well as (?(name).
2480        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2481            groups (named and numbered) that are never evaluated inline, but can be
2482            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2483            is always false. There may be only one alternative in such a group.
2485        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2486            as the simple (?(R). The condition is true only if the most recent
2487            recursion is that of the given number or name. It does not search out
2488            through the entire recursion stack.
2490        (g) The escape \gN or \g{N} has been added, where N is a positive or
2491            negative number, specifying an absolute or relative reference.
2493    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2494        some "unreachable code" warnings.
2496    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2497        things, this adds five new scripts.
2499    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2500        There were also incompatibilities regarding the handling of \Q..\E inside
2501        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2502        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2504    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2505        matches an empty string, and forcibly breaks the loop. There were bugs in
2506        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2507        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2508        separate and independent bugs (that affected different cases) have been
2509        fixed.
2511    39. Refactored the code to abolish the use of different opcodes for small
2512        capturing bracket numbers. This is a tidy that I avoided doing when I
2513        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2514        The new approach is not only tidier, it makes it possible to reduce the
2515        memory needed to fix the previous bug (38).
2517    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2518        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2519        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2520        mode.
2522    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2523        report.
2525    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2526        copy construction and assignment in the C++ wrapper.
2528    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2529        couple of bugs that could have given wrong results in the "--newline=crlf"
2530        case.
2532    44. Added a number of casts and did some reorganization of signed/unsigned int
2533        variables following suggestions from Dair Grant. Also renamed the variable
2534        "this" as "item" because it is a C++ keyword.
2536    45. Arranged for dftables to add
2538          #include "pcre_internal.h"
2540        to pcre_chartables.c because without it, gcc 4.x may remove the array
2541        definition from the final binary if PCRE is built into a static library and
2542        dead code stripping is activated.
2544    46. For an unanchored pattern, if a match attempt fails at the start of a
2545        newline sequence, and the newline setting is CRLF or ANY, and the next two
2546        characters are CRLF, advance by two characters instead of one.
2549    Version 6.7 04-Jul-06
2550    ---------------------
2552     1. In order to handle tests when input lines are enormously long, pcretest has
2553        been re-factored so that it automatically extends its buffers when
2554        necessary. The code is crude, but this _is_ just a test program. The
2555        default size has been increased from 32K to 50K.
2557     2. The code in pcre_study() was using the value of the re argument before
2558        testing it for NULL. (Of course, in any sensible call of the function, it
2559        won't be NULL.)
2561     3. The memmove() emulation function in pcre_internal.h, which is used on
2562        systems that lack both memmove() and bcopy() - that is, hardly ever -
2563        was missing a "static" storage class specifier.
2565     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2566        containing an extended class (one that cannot be represented by a bitmap
2567        because it contains high-valued characters or Unicode property items, e.g.
2568        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2569        pattern, but PCRE should not loop if you do not (it no longer does).
2570        [Detail: two cases were found: (a) a repeated subpattern containing an
2571        extended class; (b) a recursive reference to a subpattern that followed a
2572        previous extended class. It wasn't skipping over the extended class
2573        correctly when UTF-8 mode was not set.]
2575     5. A negated single-character class was not being recognized as fixed-length
2576        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2577        compile error "lookbehind assertion is not fixed length".
2579     6. The RunPerlTest auxiliary script was showing an unexpected difference
2580        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2581        write a Perl script that can interpret lines of an input file either as
2582        byte characters or as UTF-8, which is what "perltest" was being required to
2583        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2584        can't do is switch easily at run time between having the "use utf8;" pragma
2585        or not. In the end, I fudged it by using the RunPerlTest script to insert
2586        "use utf8;" explicitly for the UTF-8 tests.
2588     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2589        the end of the subject string, contrary to the documentation and to what
2590        Perl does. This was true of both matching functions. Now it matches only at
2591        the start of the subject and immediately after *internal* newlines.
2593     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2594        a pointer to an int instead of a pointer to an unsigned long int. This
2595        caused problems on 64-bit systems.
2597     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2598        instance of the 'standard' template library not being so standard".
2600    10. There was no check on the number of named subpatterns nor the maximum
2601        length of a subpattern name. The product of these values is used to compute
2602        the size of the memory block for a compiled pattern. By supplying a very
2603        long subpattern name and a large number of named subpatterns, the size
2604        computation could be caused to overflow. This is now prevented by limiting
2605        the length of names to 32 characters, and the number of named subpatterns
2606        to 10,000.
2608    11. Subpatterns that are repeated with specific counts have to be replicated in
2609        the compiled pattern. The size of memory for this was computed from the
2610        length of the subpattern and the repeat count. The latter is limited to
2611        65535, but there was no limit on the former, meaning that integer overflow
2612        could in principle occur. The compiled length of a repeated subpattern is
2613        now limited to 30,000 bytes in order to prevent this.
2615    12. Added the optional facility to have named substrings with the same name.
2617    13. Added the ability to use a named substring as a condition, using the
2618        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2619        are numbers (not recommended). Forward references are permitted.
2621    14. Added forward references in named backreferences (if you see what I mean).
2623    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2624        pattern could run off the end of the subject. For example, the pattern
2625        "(?s)(.{1,5})"8 did this with the subject "ab".
2627    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2628        PCRE_CASELESS was set when matching characters that were quantified with ?
2629        or *.
2631    17. A character class other than a single negated character that had a minimum
2632        but no maximum quantifier - for example [ab]{6,} - was not handled
2633        correctly by pce_dfa_exec(). It would match only one character.
2635    18. A valid (though odd) pattern that looked like a POSIX character
2636        class but used an invalid character after [ (for example [[,abc,]]) caused
2637        pcre_compile() to give the error "Failed: internal error: code overflow" or
2638        in some cases to crash with a glibc free() error. This could even happen if
2639        the pattern terminated after [[ but there just happened to be a sequence of
2640        letters, a binary zero, and a closing ] in the memory that followed.
2642    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2643        over the years. Originally (before any Unicode support), just the bottom 8
2644        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2645        output from "man perlunicode" includes this:
2647          The regular expression compiler produces polymorphic opcodes.  That
2648          is, the pattern adapts to the data and automatically switches to
2649          the Unicode character scheme when presented with Unicode data--or
2650          instead uses a traditional byte scheme when presented with byte
2651          data.
2653        Sadly, a wide octal escape does not cause a switch, and in a string with
2654        no other multibyte characters, these octal escapes are treated as before.
2655        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2656        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2657        Unicode string.
2659        I have not perpetrated such confusion in PCRE. Up till now, it took just
2660        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2661        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2662        translate to the appropriate multibyte character.
2664    29. Applied some refactoring to reduce the number of warnings from Microsoft
2665        and Borland compilers. This has included removing the fudge introduced
2666        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2667        a warning about an unused variable.
2669    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2670        characters since release 4.0, because Perl (from release 5.004) does not.
2671        [Or at least, is documented not to: some releases seem to be in conflict
2672        with the documentation.] However, when a pattern was studied with
2673        pcre_study() and all its branches started with \s, PCRE still included VT
2674        as a possible starting character. Of course, this did no harm; it just
2675        caused an unnecessary match attempt.
2677    22. Removed a now-redundant internal flag bit that recorded the fact that case
2678        dependency changed within the pattern. This was once needed for "required
2679        byte" processing, but is no longer used. This recovers a now-scarce options
2680        bit. Also moved the least significant internal flag bit to the most-
2681        significant bit of the word, which was not previously used (hangover from
2682        the days when it was an int rather than a uint) to free up another bit for
2683        the future.
2685    23. Added support for CRLF line endings as well as CR and LF. As well as the
2686        default being selectable at build time, it can now be changed at runtime
2687        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2688        specify that it is scanning data with non-default line endings.
2690    24. Changed the definition of CXXLINK to make it agree with the definition of
2691        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2693    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2694        recursions. This makes a big different to stack usage for some patterns.
2696    26. If a subpattern containing a named recursion or subroutine reference such
2697        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2698        the space required for the compiled pattern went wrong and gave too small a
2699        value. Depending on the environment, this could lead to "Failed: internal
2700        error: code overflow at offset 49" or "glibc detected double free or
2701        corruption" errors.
2703    27. Applied patches from Google (a) to support the new newline modes and (b) to
2704        advance over multibyte UTF-8 characters in GlobalReplace.
2706    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2707        difference for some implementation of PCRE in some Windows version.
2709    29. Added some extra testing facilities to pcretest:
2711        \q<number>   in a data line sets the "match limit" value
2712        \Q<number>   in a data line sets the "match recursion limt" value
2713        -S <number>  sets the stack size, where <number> is in megabytes
2715        The -S option isn't available for Windows.
2718    Version 6.6 06-Feb-06
2719    ---------------------
2721     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2722        in pcreposix.h. I have copied the definition from pcre.h.
2724     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2725        because pcre.h is no longer a built file.
2727     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2728        not normally included in the compiled code.
2731    Version 6.5 01-Feb-06
2732    ---------------------
2734     1. When using the partial match feature with pcre_dfa_exec(), it was not
2735        anchoring the second and subsequent partial matches at the new starting
2736        point. This could lead to incorrect results. For example, with the pattern
2737        /1234/, partially matching against "123" and then "a4" gave a match.
2739     2. Changes to pcregrep:
2741        (a) All non-match returns from pcre_exec() were being treated as failures
2742            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2743            error message is output. Some extra information is given for the
2744            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2745            probably the only errors that are likely to be caused by users (by
2746            specifying a regex that has nested indefinite repeats, for instance).
2747            If there are more than 20 of these errors, pcregrep is abandoned.
2749        (b) A binary zero was treated as data while matching, but terminated the
2750            output line if it was written out. This has been fixed: binary zeroes
2751            are now no different to any other data bytes.
2753        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2754            used to set a locale for matching. The --locale=xxxx long option has
2755            been added (no short equivalent) to specify a locale explicitly on the
2756            pcregrep command, overriding the environment variables.
2758        (d) When -B was used with -n, some line numbers in the output were one less
2759            than they should have been.
2761        (e) Added the -o (--only-matching) option.
2763        (f) If -A or -C was used with -c (count only), some lines of context were
2764            accidentally printed for the final match.
2766        (g) Added the -H (--with-filename) option.
2768        (h) The combination of options -rh failed to suppress file names for files
2769            that were found from directory arguments.
2771        (i) Added the -D (--devices) and -d (--directories) options.
2773        (j) Added the -F (--fixed-strings) option.
2775        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2777        (l) Added the --colo(u)r option.
2779        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2780            is not present by default.
2782     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2783        items such as (?R) or (?1), when the recursion could match a number of
2784        alternatives. If it matched one of the alternatives, but subsequently,
2785        outside the recursion, there was a failure, the code tried to back up into
2786        the recursion. However, because of the way PCRE is implemented, this is not
2787        possible, and the result was an incorrect result from the match.
2789        In order to prevent this happening, the specification of recursion has
2790        been changed so that all such subpatterns are automatically treated as
2791        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2793     4. I had overlooked the fact that, in some locales, there are characters for
2794        which isalpha() is true but neither isupper() nor islower() are true. In
2795        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2796        and ordfeminine) are like this. This affected the treatment of \w and \W
2797        when they appeared in character classes, but not when they appeared outside
2798        a character class. The bit map for "word" characters is now created
2799        separately from the results of isalnum() instead of just taking it from the
2800        upper, lower, and digit maps. (Plus the underscore character, of course.)
2802     5. The above bug also affected the handling of POSIX character classes such as
2803        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2804        permanent tables. Instead, the bit maps for such a class were previously
2805        created as the appropriate unions of the upper, lower, and digit bitmaps.
2806        Now they are created by subtraction from the [[:word:]] class, which has
2807        its own bitmap.
2809     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2810        It is created by subtracting the vertical space characters (\x09, \x0a,
2811        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2812        subtraction was done in the overall bitmap for a character class, meaning
2813        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2814        be recognized. This bug has been fixed.
2816     7. Patches from the folks at Google:
2818          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2819          real life, but is still worth protecting against".
2821          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2822          regular expressions".
2824          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2825          have it.
2827          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2828          "configure" and the latter not, in order to fix a problem somebody had
2829          with compiling the Arg class on HP-UX.
2831          (e) Improve the error-handling of the C++ wrapper a little bit.
2833          (f) New tests for checking recursion limiting.
2835     8. The pcre_memmove() function, which is used only if the environment does not
2836        have a standard memmove() function (and is therefore rarely compiled),
2837        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2838        returning a result (though PCRE never actually uses the result).
2840     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2841        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2842        returned instead of calling malloc() with an overflowing number that would
2843        most likely cause subsequent chaos.
2845    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2847    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2848        with this option is matched, the nmatch and pmatch options of regexec() are
2849        ignored.
2851    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2852        provided in case anyone wants to the the POSIX interface with UTF-8
2853        strings.
2855    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2856        C++ linking (needed for some HP-UX environments).
2858    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2859        (unused parameter) and in the pcre_printint() function (omitted "default"
2860        switch label when the default is to do nothing).
2862    15. Added some code to make it possible, when PCRE is compiled as a C++
2863        library, to replace subject pointers for pcre_exec() with a smart pointer
2864        class, thus making it possible to process discontinuous strings.
2866    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2867        much the same function. They were added by different people who were trying
2868        to make PCRE easy to compile on non-Unix systems. It has been suggested
2869        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2870        for compiling on Windows systems. I have therefore replaced it with
2871        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2872        defaults to "extern" for C or "extern C" for C++, which works fine on
2873        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2874        SCOPE with something explicit in config.h. In addition:
2876        (a) pcreposix.h still had just "extern" instead of either of these macros;
2877            I have replaced it with PCRE_DATA_SCOPE.
2879        (b) Functions such as _pcre_xclass(), which are internal to the library,
2880            but external in the C sense, all had PCRE_EXPORT in their definitions.
2881            This is apparently wrong for the Windows case, so I have removed it.
2882            (It makes no difference on Unix-like systems.)
2884    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2885        of recursive calls to match(). This is different to MATCH_LIMIT because
2886        that limits the total number of calls to match(), not all of which increase
2887        the depth of recursion. Limiting the recursion depth limits the amount of
2888        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2889        when PCRE is compiled, and changed at run time. A patch from Google adds
2890        this functionality to the C++ interface.
2892    18. Changes to the handling of Unicode character properties:
2894        (a) Updated the table to Unicode 4.1.0.
2896        (b) Recognize characters that are not in the table as "Cn" (undefined).
2898        (c) I revised the way the table is implemented to a much improved format
2899            which includes recognition of ranges. It now supports the ranges that
2900            are defined in UnicodeData.txt, and it also amalgamates other
2901            characters into ranges. This has reduced the number of entries in the
2902            table from around 16,000 to around 3,000, thus reducing its size
2903            considerably. I realized I did not need to use a tree structure after
2904            all - a binary chop search is just as efficient. Having reduced the
2905            number of entries, I extended their size from 6 bytes to 8 bytes to
2906            allow for more data.
2908        (d) Added support for Unicode script names via properties such as \p{Han}.
2910    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2911        matching that character.
2913    20. When matching a repeated Unicode property with a minimum greater than zero,
2914        (for example \pL{2,}), PCRE could look past the end of the subject if it
2915        reached it while seeking the minimum number of characters. This could
2916        happen only if some of the characters were more than one byte long, because
2917        there is a check for at least the minimum number of bytes.
2919    21. Refactored the implementation of \p and \P so as to be more general, to
2920        allow for more different types of property in future. This has changed the
2921        compiled form incompatibly. Anybody with saved compiled patterns that use
2922        \p or \P will have to recompile them.
2924    22. Added "Any" and "L&" to the supported property types.
2926    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2927        but give a compile time error if the value is greater than 0xff.
2929    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2930        accidentally not being installed or uninstalled.
2932    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2933        made were to insert the current release number. This seemed silly, because
2934        it made things harder for people building PCRE on systems that don't run
2935        "configure". I have turned pcre.h into a distributed file, no longer built
2936        by "configure", with the version identification directly included. There is
2937        no longer a pcre.h.in file.
2939        However, this change necessitated a change to the pcre-config script as
2940        well. It is built from pcre-config.in, and one of the substitutions was the
2941        release number. I have updated configure.ac so that ./configure now finds
2942        the release number by grepping pcre.h.
2944    26. Added the ability to run the tests under valgrind.
2947    Version 6.4 05-Sep-05
2948    ---------------------
2950     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2951        "--" to be printed when multiple files were scanned, even when none of the
2952        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2953        consider it to be a bug, and have restored the previous behaviour.
2955     2. A couple of code tidies to get rid of compiler warnings.
2957     3. The pcretest program used to cheat by referring to symbols in the library
2958        whose names begin with _pcre_. These are internal symbols that are not
2959        really supposed to be visible externally, and in some environments it is
2960        possible to suppress them. The cheating is now confined to including
2961        certain files from the library's source, which is a bit cleaner.
2963     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2964        file's purpose clearer.
2966     5. Reorganized pcre_ucp_findchar().
2969    Version 6.3 15-Aug-05
2970    ---------------------
2972     1. The file libpcre.pc.in did not have general read permission in the tarball.
2974     2. There were some problems when building without C++ support:
2976        (a) If C++ support was not built, "make install" and "make test" still
2977            tried to test it.
2979        (b) There were problems when the value of CXX was explicitly set. Some
2980            changes have been made to try to fix these, and ...
2982        (c) --disable-cpp can now be used to explicitly disable C++ support.
2984        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2985            backslash in a target when C++ was disabled. This confuses some
2986            versions of "make", apparently. Using an intermediate variable solves
2987            this. (Same for CPP_LOBJ.)
2989     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2990        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2991        necessary on certain architectures.
2993     4. Added a setting of -export-symbols-regex to the link command to remove
2994        those symbols that are exported in the C sense, but actually are local
2995        within the library, and not documented. Their names all begin with
2996        "_pcre_". This is not a perfect job, because (a) we have to except some
2997        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2998        available (and never for static libraries). I have made a note to try to
2999        find a way round (a) in the future.
3002    Version 6.2 01-Aug-05
3003    ---------------------
3005     1. There was no test for integer overflow of quantifier values. A construction
3006        such as {1111111111111111} would give undefined results. What is worse, if
3007        a minimum quantifier for a parenthesized subpattern overflowed and became
3008        negative, the calculation of the memory size went wrong. This could have
3009        led to memory overwriting.
3011     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
3013     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
3014        operating environments where this matters.
3016     4. Applied Giuseppe Maxia's patch to add additional features for controlling
3017        PCRE options from within the C++ wrapper.
3019     5. Named capturing subpatterns were not being correctly counted when a pattern
3020        was compiled. This caused two problems: (a) If there were more than 100
3021        such subpatterns, the calculation of the memory needed for the whole
3022        compiled pattern went wrong, leading to an overflow error. (b) Numerical
3023        back references of the form \12, where the number was greater than 9, were
3024        not recognized as back references, even though there were sufficient
3025        previous subpatterns.
3027     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
3028        versions of gcc, e.g. 2.95.4.
3031    Version 6.1 21-Jun-05
3032    ---------------------
3034     1. There was one reference to the variable "posix" in pcretest.c that was not
3035        surrounded by "#if !defined NOPOSIX".
3037     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
3038        the cross-check on the old pcre_info() function, for the benefit of the
3039        cut-down version of PCRE that is currently imported into Exim.
3041     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
3042        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
3043        patterns that start (?i) but I don't think that matters. The use of (?i) is
3044        just an example; this all applies to the other options as well.
3046     4. Since libtool seems to echo the compile commands it is issuing, the output
3047        from "make" can be reduced a bit by putting "@" in front of each libtool
3048        compile command.
3050     5. Patch from the folks at Google for configure.in to be a bit more thorough
3051        in checking for a suitable C++ installation before trying to compile the
3052        C++ stuff. This should fix a reported problem when a compiler was present,
3053        but no suitable headers.
3055     6. The man pages all had just "PCRE" as their title. I have changed them to
3056        be the relevant file name. I have also arranged that these names are
3057        retained in the file doc/pcre.txt, which is a concatenation in text format
3058        of all the man pages except the little individual ones for each function.
3060     7. The NON-UNIX-USE file had not been updated for the different set of source
3061        files that come with release 6. I also added a few comments about the C++
3062        wrapper.
3065    Version 6.0 07-Jun-05
3066    ---------------------
3068     1. Some minor internal re-organization to help with my DFA experiments.
3070     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
3071        didn't matter for the library itself when fully configured, but did matter
3072        when compiling without UCP support, or within Exim, where the ucp files are
3073        not imported.
3075     3. Refactoring of the library code to split up the various functions into
3076        different source modules. The addition of the new DFA matching code (see
3077        below) to a single monolithic source would have made it really too
3078        unwieldy, quite apart from causing all the code to be include in a
3079        statically linked application, when only some functions are used. This is
3080        relevant even without the DFA addition now that patterns can be compiled in
3081        one application and matched in another.
3083        The downside of splitting up is that there have to be some external
3084        functions and data tables that are used internally in different modules of
3085        the library but which are not part of the API. These have all had their
3086        names changed to start with "_pcre_" so that they are unlikely to clash
3087        with other external names.
3089     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
3090        a different (DFA) algorithm. Although it is slower than the original
3091        function, it does have some advantages for certain types of matching
3092        problem.
3094     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
3095        including restarting after a partial match.
3097     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
3098        defined when compiling for Windows was sent to me. I have put it into the
3099        code, though I have no means of testing or verifying it.
3101     7. Added the pcre_refcount() auxiliary function.
3103     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
3104        match before or at the first newline in the subject string. In pcretest,
3105        the /f option on a pattern can be used to set this.
3107     9. A repeated \w when used in UTF-8 mode with characters greater than 256
3108        would behave wrongly. This has been present in PCRE since release 4.0.
3110    10. A number of changes to the pcregrep command:
3112        (a) Refactored how -x works; insert ^(...)$ instead of setting
3113            PCRE_ANCHORED and checking the length, in preparation for adding
3114            something similar for -w.
3116        (b) Added the -w (match as a word) option.
3118        (c) Refactored the way lines are read and buffered so as to have more
3119            than one at a time available.
3121        (d) Implemented a pcregrep test script.
3123        (e) Added the -M (multiline match) option. This allows patterns to match
3124            over several lines of the subject. The buffering ensures that at least
3125            8K, or the rest of the document (whichever is the shorter) is available
3126            for matching (and similarly the previous 8K for lookbehind assertions).
3128        (f) Changed the --help output so that it now says
3130              -w, --word-regex(p)
3132            instead of two lines, one with "regex" and the other with "regexp"
3133            because that confused at least one person since the short forms are the
3134            same. (This required a bit of code, as the output is generated
3135            automatically from a table. It wasn't just a text change.)
3137        (g) -- can be used to terminate pcregrep options if the next thing isn't an
3138            option but starts with a hyphen. Could be a pattern or a path name
3139            starting with a hyphen, for instance.
3141        (h) "-" can be given as a file name to represent stdin.
3143        (i) When file names are being printed, "(standard input)" is used for
3144            the standard input, for compatibility with GNU grep. Previously
3145            "<stdin>" was used.
3147        (j) The option --label=xxx can be used to supply a name to be used for
3148            stdin when file names are being printed. There is no short form.
3150        (k) Re-factored the options decoding logic because we are going to add
3151            two more options that take data. Such options can now be given in four
3152            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
3154        (l) Added the -A, -B, and -C options for requesting that lines of context
3155            around matches be printed.
3157        (m) Added the -L option to print the names of files that do not contain
3158            any matching lines, that is, the complement of -l.
3160        (n) The return code is 2 if any file cannot be opened, but pcregrep does
3161            continue to scan other files.
3163        (o) The -s option was incorrectly implemented. For compatibility with other
3164            greps, it now suppresses the error message for a non-existent or non-
3165            accessible file (but not the return code). There is a new option called
3166            -q that suppresses the output of matching lines, which was what -s was
3167            previously doing.
3169        (p) Added --include and --exclude options to specify files for inclusion
3170            and exclusion when recursing.
3172    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
3173        Hopefully, it now does.
3175    12. Missing cast in pcre_study().
3177    13. Added an "uninstall" target to the makefile.
3179    14. Replaced "extern" in the function prototypes in Makefile.in with
3180        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
3181        world, but is set differently for Windows.
3183    15. Added a second compiling function called pcre_compile2(). The only
3184        difference is that it has an extra argument, which is a pointer to an
3185        integer error code. When there is a compile-time failure, this is set
3186        non-zero, in addition to the error test pointer being set to point to an
3187        error message. The new argument may be NULL if no error number is required
3188        (but then you may as well call pcre_compile(), which is now just a
3189        wrapper). This facility is provided because some applications need a
3190        numeric error indication, but it has also enabled me to tidy up the way
3191        compile-time errors are handled in the POSIX wrapper.
3193    16. Added VPATH=.libs to the makefile; this should help when building with one
3194        prefix path and installing with another. (Or so I'm told by someone who
3195        knows more about this stuff than I do.)
3197    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
3198        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
3199        match everything, including newlines. This is not POSIX-compatible, but
3200        somebody wanted the feature. From pcretest it can be activated by using
3201        both the P and the s flags.
3203    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
3205    19. libpcre.pc was being incorrectly installed as executable.
3207    20. A couple of places in pcretest check for end-of-line by looking for '\n';
3208        it now also looks for '\r' so that it will work unmodified on Windows.
3210    21. Added Google's contributed C++ wrapper to the distribution.
3212    22. Added some untidy missing memory free() calls in pcretest, to keep
3213        Electric Fence happy when testing.
3217    Version 5.0 13-Sep-04
3218    ---------------------
3220     1. Internal change: literal characters are no longer packed up into items
3221        containing multiple characters in a single byte-string. Each character
3222        is now matched using a separate opcode. However, there may be more than one
3223        byte in the character in UTF-8 mode.
3225     2. The pcre_callout_block structure has two new fields: pattern_position and
3226        next_item_length. These contain the offset in the pattern to the next match
3227        item, and its length, respectively.
3229     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
3230        insertion of callouts before each pattern item. Added the /C option to
3231        pcretest to make use of this.
3233     4. On the advice of a Windows user, the lines
3235          #if defined(_WIN32) || defined(WIN32)
3236          _setmode( _fileno( stdout ), 0x8000 );
3237          #endif  /* defined(_WIN32) || defined(WIN32) */
3239        have been added to the source of pcretest. This apparently does useful
3240        magic in relation to line terminators.
3242     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
3243        for the benefit of those environments where the "b" makes a difference.
3245     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
3246        to know about it. I have put a hack into configure.in that adds in code
3247        to set GCC=yes if CC=icc. This seems to end up at a point in the
3248        generated configure script that is early enough to affect the setting of
3249        compiler options, which is what is needed, but I have no means of testing
3250        whether it really works. (The user who reported this had patched the
3251        generated configure script, which of course I cannot do.)
3253        LATER: After change 22 below (new libtool files), the configure script
3254        seems to know about icc (and also ecc). Therefore, I have commented out
3255        this hack in configure.in.
3257     7. Added support for pkg-config (2 patches were sent in).
3259     8. Negated POSIX character classes that used a combination of internal tables
3260        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
3261        [[:^ascii]]. Typically, they would match almost any characters. The other
3262        POSIX classes were not broken in this way.
3264     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
3265        to find the match, as PCRE was deluded into thinking that the match had to
3266        start at the start point or following a newline. The same bug applied to
3267        patterns with negative forward assertions or any backward assertions
3268        preceding ".*" at the start, unless the pattern required a fixed first
3269        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
3271    10. In UTF-8 mode, when moving forwards in the subject after a failed match
3272        starting at the last subject character, bytes beyond the end of the subject
3273        string were read.
3275    11. Renamed the variable "class" as "classbits" to make life easier for C++
3276        users. (Previously there was a macro definition, but it apparently wasn't
3277        enough.)
3279    12. Added the new field "tables" to the extra data so that tables can be passed
3280        in at exec time, or the internal tables can be re-selected. This allows
3281        a compiled regex to be saved and re-used at a later time by a different
3282        program that might have everything at different addresses.
3284    13. Modified the pcre-config script so that, when run on Solaris, it shows a
3285        -R library as well as a -L library.
3287    14. The debugging options of pcretest (-d on the command line or D on a
3288        pattern) showed incorrect output for anything following an extended class
3289        that contained multibyte characters and which was followed by a quantifier.
3291    15. Added optional support for general category Unicode character properties
3292        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
3293        support. It adds about 90K to the size of the library. The meanings of the
3294        inbuilt class escapes such as \d and \s have NOT been changed.
3296    16. Updated pcredemo.c to include calls to free() to release the memory for the
3297        compiled pattern.
3299    17. The generated file chartables.c was being created in the source directory
3300        instead of in the building directory. This caused the build to fail if the
3301        source directory was different from the building directory, and was
3302        read-only.
3304    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
3305        file. No doubt somebody will tell me if they don't make sense... Also added
3306        Dan Mooney's comments about building on OpenVMS.
3308    19. Added support for partial matching via the PCRE_PARTIAL option for
3309        pcre_exec() and the \P data escape in pcretest.
3311    20. Extended pcretest with 3 new pattern features:
3313        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
3314              write the compiled pattern to the file whose name is "rest-of-line".
3315              This is a straight binary dump of the data, with the saved pointer to
3316              the character tables forced to be NULL. The study data, if any, is
3317              written too. After writing, pcretest reads a new pattern.
3319        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
3320              compiled pattern from the given file. There must not be any
3321              occurrences of "<" in the file name (pretty unlikely); if there are,
3322              pcretest will instead treat the initial "<" as a pattern delimiter.
3323              After reading in the pattern, pcretest goes on to read data lines as
3324              usual.
3326        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
3327              and 16-bit fields in a compiled pattern, to simulate a pattern that
3328              was compiled on a host of opposite endianness.
3330    21. The pcre-exec() function can now cope with patterns that were compiled on
3331        hosts of opposite endianness, with this restriction:
3333          As for any compiled expression that is saved and used later, the tables
3334          pointer field cannot be preserved; the extra_data field in the arguments
3335          to pcre_exec() should be used to pass in a tables address if a value
3336          other than the default internal tables were used at compile time.
3338    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
3339        now diagnosed as an error. Previously, most of the time, a negative number
3340        would have been treated as zero, but if in addition "ovector" was passed as
3341        NULL, a crash could occur.
3343    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
3344        new versions from the libtool 1.5 distribution (the last one is a copy of
3345        a file called libtool.m4). This seems to have fixed the need to patch
3346        "configure" to support Darwin 1.3 (which I used to do). However, I still
3347        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
3348        workstation).
3350    24. Changed the PCRE licence to be the more standard "BSD" licence.
3353    Version 4.5 01-Dec-03
3354    ---------------------
3356     1. There has been some re-arrangement of the code for the match() function so
3357        that it can be compiled in a version that does not call itself recursively.
3358        Instead, it keeps those local variables that need separate instances for
3359        each "recursion" in a frame on the heap, and gets/frees frames whenever it
3360        needs to "recurse". Keeping track of where control must go is done by means
3361        of setjmp/longjmp. The whole thing is implemented by a set of macros that
3362        hide most of the details from the main code, and operates only if
3363        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
3364        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
3365        operating.
3367        To make it easier for callers to provide specially tailored get/free
3368   &nbs