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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.6 21-Jan-08  Version 8.32
5    ------------
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
13    3.  Single character iterator optimizations in the JIT compiler.
15    4.  Improved JIT compiler optimizations for character ranges.
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
29    Version 8.31 06-July-2012
30    -------------------------
32    1.  Fixing a wrong JIT test case and some compiler warnings.
34    2.  Removed a bashism from the RunTest script.
36    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
37        to unsigned type, result still unsigned" that was given by an MS compiler
38        on encountering the code "-sizeof(xxx)".
40    4.  Partial matching support is added to the JIT compiler.
42    5.  Fixed several bugs concerned with partial matching of items that consist
43        of more than one character:
45        (a) /^(..)\1/ did not partially match "aba" because checking references was
46            done on an "all or nothing" basis. This also applied to repeated
47            references.
49        (b) \R did not give a hard partial match if \r was found at the end of the
50            subject.
52        (c) \X did not give a hard partial match after matching one or more
53            characters at the end of the subject.
55        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
56            a partial match for the string "\r".
58        (e) When newline was set to CRLF, the metacharacter "." did not recognize
59            a partial match for a CR character at the end of the subject string.
61    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
62        running pcretest, the text "(JIT)" added to the output whenever JIT is
63        actually used to run the match.
65    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
66        or /S+[+] with a digit between 1 and 7.
68    8.  OP_NOT now supports any UTF character not just single-byte ones.
70    9.  (*MARK) control verb is now supported by the JIT compiler.
72    10. The command "./RunTest list" lists the available tests without actually
73        running any of them. (Because I keep forgetting what they all are.)
77    12. Applied a (slightly modified) user-supplied patch that improves performance
78        when the heap is used for recursion (compiled with --disable-stack-for-
79        recursion). Instead of malloc and free for each heap frame each time a
80        logical recursion happens, frames are retained on a chain and re-used where
81        possible. This sometimes gives as much as 30% improvement.
83    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
84        call.
86    14. As documented, (*COMMIT) is now confined to within a positive assertion.
88    15. It is now possible to link pcretest with libedit as an alternative to
89        libreadline.
91    16. (*COMMIT) control verb is now supported by the JIT compiler.
93    17. The Unicode data tables have been updated to Unicode 6.1.0.
95    18. Added --file-list option to pcregrep.
97    19. Added binary file support to pcregrep, including the -a, --binary-files,
98        -I, and --text options.
100    20. The madvise function is renamed for posix_madvise for QNX compatibility
101        reasons. Fixed by Giuseppe D'Angelo.
103    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
105    22. Changed the option for creating symbolic links for 16-bit man pages from
106        -s to -sf so that re-installing does not cause issues.
108    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
110    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
111        matches in certain environments (the workspace was not being correctly
112        retained). Also added to pcre_dfa_exec() a simple plausibility check on
113        some of the workspace data at the beginning of a restart.
115    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
116        was not doing so when it should - probably a typo introduced by SVN 528
117        (change 8.10/14).
119    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
120        \w+ when the character tables indicated that \x{c4} was a word character.
121        There were several related cases, all because the tests for doing a table
122        lookup were testing for characters less than 127 instead of 255.
124    27. If a pattern contains capturing parentheses that are not used in a match,
125        their slots in the ovector are set to -1. For those that are higher than
126        any matched groups, this happens at the end of processing. In the case when
127        there were back references that the ovector was too small to contain
128        (causing temporary malloc'd memory to be used during matching), and the
129        highest capturing number was not used, memory off the end of the ovector
130        was incorrectly being set to -1. (It was using the size of the temporary
131        memory instead of the true size.)
133    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
134        ovector size, it uses memory at the end of the block that it has got.
136    29. Check for an overlong MARK name and give an error at compile time. The
137        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
139    30. JIT compiler update.
141    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
142        Rill for the patch.
144    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
146    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
148    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
149        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
150        was enabled.
152    35. Improve JIT code generation for greedy plus quantifier.
154    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
155        1 to "aa" instead of to an empty string. The bug affected repeated groups
156        that could potentially match an empty string.
158    37. Optimizing single character iterators in JIT.
160    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
161        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
162        codepoints that are too big for the mode are faulted, and in a UTF mode,
163        disallowed codepoints are also faulted.
165    39. If PCRE was compiled with UTF support, in three places in the DFA
166        matcher there was code that should only have been obeyed in UTF mode, but
167        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
168        processing when bytes with values greater than 127 were present. In 16-bit
169        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
170        both cases the values are those that cannot be the first data item in a UTF
171        character. The three items that might have provoked this were recursions,
172        possessively repeated groups, and atomic groups.
174    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
175        and pcregrep, because some OS require shared objects to be explicitly
176        passed to ld, causing the link step to fail if they are not.
178    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
179        mode, patterns that started with \h* or \R* might be incorrectly matched.
182    Version 8.30 04-February-2012
183    -----------------------------
185    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
186        name is defined in ctype.h.
188    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
189        only in quite long subpatterns.
191    3.  Removed the function pcre_info(), which has been obsolete and deprecated
192        since it was replaced by pcre_fullinfo() in February 2000.
194    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
195        match a (*MARK), and the match failed at the start of the subject, a
196        reference to memory before the start of the subject could occur. This bug
197        was introduced by fix 17 of release 8.21.
199    5.  A reference to an unset group with zero minimum repetition was giving
200        totally wrong answers (in non-JavaScript-compatibility mode). For example,
201        /(another)?(\1?)test/ matched against "hello world test". This bug was
202        introduced in release 8.13.
204    6.  Add support for 16-bit character strings (a large amount of work involving
205        many changes and refactorings).
207    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
208        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
209        from a file.
211    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
212        rounding is not applied in this particular case).
214    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
215        if they appear, or are escaped, in patterns.
217    10. Get rid of a number of -Wunused-but-set-variable warnings.
219    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
220        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
221        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
222        also returns the mark "x". This bug applied to capturing parentheses,
223        non-capturing parentheses, and atomic parentheses. It also applied to some
224        assertions.
226    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
227        information out of configure.ac instead of relying on pcre.h.generic, which
228        is not stored in the repository.
230    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
231        -lreadline.
233    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
235    15. Applied Graycode's patch to put the top-level frame on the stack rather
236        than the heap when not using the stack for recursion. This gives a
237        performance improvement in many cases when recursion is not deep.
239    16. Experimental code added to "pcretest -C" to output the stack frame size.
242    Version 8.21 12-Dec-2011
243    ------------------------
245    1.  Updating the JIT compiler.
247    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
248        are added as well.
250    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
251        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
252        calling _pcre_jit_exec. Some extra comments are added.
254    4.  (*MARK) settings inside atomic groups that do not contain any capturing
255        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
256        was introduced by change 18 for 8.20.
258    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
259        ECMA-262 standard.
261    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
262        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
263        This bug was probably introduced by change 9 of 8.13.
265    7.  While fixing 6 above, I noticed that a number of other items were being
266        incorrectly rejected as "not fixed length". This arose partly because newer
267        opcodes had not been added to the fixed-length checking code. I have (a)
268        corrected the bug and added tests for these items, and (b) arranged for an
269        error to occur if an unknown opcode is encountered while checking for fixed
270        length instead of just assuming "not fixed length". The items that were
271        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
272        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
273        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
275    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
276        being incorrectly compiled and would have given unpredicatble results.
278    9.  A possessively repeated subpattern with minimum repeat count greater than
279        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
280        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
281        the first (A) could occur when it should not.
283    10. Add a cast and remove a redundant test from the code.
285    11. JIT should use pcre_malloc/pcre_free for allocation.
287    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
288        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
289        is anything other than /usr, -L is still shown).
291    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
293    14. Perl does not support \N without a following name in a [] class; PCRE now
294        also gives an error.
296    15. If a forward reference was repeated with an upper limit of around 2000,
297        it caused the error "internal error: overran compiling workspace". The
298        maximum number of forward references (including repeats) was limited by the
299        internal workspace, and dependent on the LINK_SIZE. The code has been
300        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
301        the default depends on LINK_SIZE. There is a new upper limit (for safety)
302        of around 200,000 forward references. While doing this, I also speeded up
303        the filling in of repeated forward references.
305    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
306        incorrectly expecting the subject to contain another "a" after the start.
308    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
309        in the match, the SKIP should be ignored. This was not happening; instead
310        the SKIP was being treated as NOMATCH. For patterns such as
311        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
312        tested.
314    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
315        now much more compatible with Perl, in particular in cases where the result
316        is a non-match for a non-anchored pattern. For example, if
317        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
318        "m", where previously it did not return a name. A side effect of this
319        change is that for partial matches, the last encountered mark name is
320        returned, as for non matches. A number of tests that were previously not
321        Perl-compatible have been moved into the Perl-compatible test files. The
322        refactoring has had the pleasing side effect of removing one argument from
323        the match() function, thus reducing its stack requirements.
325    19. If the /S+ option was used in pcretest to study a pattern using JIT,
326        subsequent uses of /S (without +) incorrectly behaved like /S+.
328    21. Retrieve executable code size support for the JIT compiler and fixing
329        some warnings.
331    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
332        not work when the shorter character appeared right at the end of the
333        subject string.
335    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
336        systems.
338    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
339        output it when the /M option is used in pcretest.
341    25. The CheckMan script was not being included in the distribution. Also, added
342        an explicit "perl" to run Perl scripts from the PrepareRelease script
343        because this is reportedly needed in Windows.
345    26. If study data was being save in a file and studying had not found a set of
346        "starts with" bytes for the pattern, the data written to the file (though
347        never used) was taken from uninitialized memory and so caused valgrind to
348        complain.
350    27. Updated RunTest.bat as provided by Sheri Pierce.
352    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
354    29. Computation of memory usage for the table of capturing group names was
355        giving an unnecessarily large value.
358    Version 8.20 21-Oct-2011
359    ------------------------
361    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
362        a POSIX class. After further experiments with Perl, which convinced me that
363        Perl has bugs and confusions, a closing square bracket is no longer allowed
364        in a POSIX name. This bug also affected patterns with classes that started
365        with full stops.
367    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
368        captured substring, but while checking the failing first alternative,
369        substring 1 is temporarily captured. If the output vector supplied to
370        pcre_exec() was not big enough for this capture, the yield of the function
371        was still zero ("insufficient space for captured substrings"). This cannot
372        be totally fixed without adding another stack variable, which seems a lot
373        of expense for a edge case. However, I have improved the situation in cases
374        such as /(a)(b)x|abc/ matched against "abc", where the return code
375        indicates that fewer than the maximum number of slots in the ovector have
376        been set.
378    3.  Related to (2) above: when there are more back references in a pattern than
379        slots in the output vector, pcre_exec() uses temporary memory during
380        matching, and copies in the captures as far as possible afterwards. It was
381        using the entire output vector, but this conflicts with the specification
382        that only 2/3 is used for passing back captured substrings. Now it uses
383        only the first 2/3, for compatibility. This is, of course, another edge
384        case.
386    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
387        main code base, and can be used by building with --enable-jit. When this is
388        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
389        runtime --no-jit option is given.
391    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
392        ovector, the return from the function was zero, implying that there were
393        other matches that did not fit. The correct "exactly full" value is now
394        returned.
396    6.  If a subpattern that was called recursively or as a subroutine contained
397        (*PRUNE) or any other control that caused it to give a non-standard return,
398        invalid errors such as "Error -26 (nested recursion at the same subject
399        position)" or even infinite loops could occur.
401    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
402        computing the minimum length on reaching *ACCEPT, and so ended up with the
403        wrong value of 1 rather than 0. Further investigation indicates that
404        computing a minimum subject length in the presence of *ACCEPT is difficult
405        (think back references, subroutine calls), and so I have changed the code
406        so that no minimum is registered for a pattern that contains *ACCEPT.
408    8.  If (*THEN) was present in the first (true) branch of a conditional group,
409        it was not handled as intended. [But see 16 below.]
411    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
412        Sheri Pierce.
414    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
415        the first byte in a match must be "a".
417    11. Change 17 for 8.13 increased the recursion depth for patterns like
418        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
419        pattern contains any instances of (*THEN). If it does not, the old
420        optimizations are restored. It would be nice to do this on a per-group
421        basis, but at the moment that is not feasible.
423    12. In some environments, the output of pcretest -C is CRLF terminated. This
424        broke RunTest's code that checks for the link size. A single white space
425        character after the value is now allowed for.
427    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
428        For "fr", it uses the Windows-specific input and output files.
430    14. If (*THEN) appeared in a group that was called recursively or as a
431        subroutine, it did not work as intended. [But see next item.]
433    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
434        pattern fragments (but not containing any | characters). If A and B are
435        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
436        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
437        D. In other words, Perl considers parentheses that do not contain any |
438        characters to be part of a surrounding alternative, whereas PCRE was
439        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
440        differently. PCRE now behaves in the same way as Perl, except in the case
441        of subroutine/recursion calls such as (?1) which have in any case always
442        been different (but PCRE had them first :-).
444    16. Related to 15 above: Perl does not treat the | in a conditional group as
445        creating alternatives. Such a group is treated in the same way as an
446        ordinary group without any | characters when processing (*THEN). PCRE has
447        been changed to match Perl's behaviour.
449    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
450        RunGrepTest script failed.
452    18. Change 22 for version 13 caused atomic groups to use more stack. This is
453        inevitable for groups that contain captures, but it can lead to a lot of
454        stack use in large patterns. The old behaviour has been restored for atomic
455        groups that do not contain any capturing parentheses.
457    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
458        suppress the check for a minimum subject length at run time. (If it was
459        given to pcre_exec() or pcre_dfa_exec() it did work.)
461    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
462        fail to work when decoding hex characters in data strings in EBCDIC
463        environments.
465    21. It appears that in at least one Mac OS environment, the isxdigit() function
466        is implemented as a macro that evaluates to its argument more than once,
467        contravening the C 90 Standard (I haven't checked a later standard). There
468        was an instance in pcretest which caused it to go wrong when processing
469        \x{...} escapes in subject strings. The has been rewritten to avoid using
470        things like p++ in the argument of isxdigit().
473    Version 8.13 16-Aug-2011
474    ------------------------
476    1.  The Unicode data tables have been updated to Unicode 6.0.0.
478    2.  Two minor typos in pcre_internal.h have been fixed.
480    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
481        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
482        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
484    4.  There were a number of related bugs in the code for matching backrefences
485        caselessly in UTF-8 mode when codes for the characters concerned were
486        different numbers of bytes. For example, U+023A and U+2C65 are an upper
487        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
488        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
489        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
490        2-byte code at the end of the subject (it thought there wasn't enough data
491        left).
493    5.  Comprehensive information about what went wrong is now returned by
494        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
495        as the output vector has at least 2 elements. The offset of the start of
496        the failing character and a reason code are placed in the vector.
498    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
499        now returned is for the first byte of the failing character, instead of the
500        last byte inspected. This is an incompatible change, but I hope it is small
501        enough not to be a problem. It makes the returned offset consistent with
502        pcre_exec() and pcre_dfa_exec().
504    7.  pcretest now gives a text phrase as well as the error number when
505        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
506        failure, the offset and reason code are output.
508    8.  When \R was used with a maximizing quantifier it failed to skip backwards
509        over a \r\n pair if the subsequent match failed. Instead, it just skipped
510        back over a single character (\n). This seems wrong (because it treated the
511        two characters as a single entity when going forwards), conflicts with the
512        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
513        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
514        has been changed.
516    9.  Some internal refactoring has changed the processing so that the handling
517        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
518        time (the PCRE_DOTALL option was changed this way some time ago: version
519        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
520        which was always a bit of a fudge. It also means that there is one less
521        argument for the match() function, which reduces its stack requirements
522        slightly. This change also fixes an incompatibility with Perl: the pattern
523        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
525    10. More internal refactoring has drastically reduced the number of recursive
526        calls to match() for possessively repeated groups such as (abc)++ when
527        using pcre_exec().
529    11. While implementing 10, a number of bugs in the handling of groups were
530        discovered and fixed:
532        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
533        (a|)*(?1) gave a compile-time internal error.
534        ((a|)+)+  did not notice that the outer group could match an empty string.
535        (^a|^)+   was not marked as anchored.
536        (.*a|.*)+ was not marked as matching at start or after a newline.
538    12. Yet more internal refactoring has removed another argument from the match()
539        function. Special calls to this function are now indicated by setting a
540        value in a variable in the "match data" data block.
542    13. Be more explicit in pcre_study() instead of relying on "default" for
543        opcodes that mean there is no starting character; this means that when new
544        ones are added and accidentally left out of pcre_study(), testing should
545        pick them up.
547    14. The -s option of pcretest has been documented for ages as being an old
548        synonym of -m (show memory usage). I have changed it to mean "force study
549        for every regex", that is, assume /S for every regex. This is similar to -i
550        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
551        using it. It makes it easier to run collections of tests with and without
552        study enabled, and thereby test pcre_study() more easily. All the standard
553        tests are now run with and without -s (but some patterns can be marked as
554        "never study" - see 20 below).
556    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
557        restoration of the capturing data to the outer values was not happening
558        correctly.
560    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
561        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
562        pattern had matched an empty string, and so incorrectly returned a no
563        match.
565    17. There was optimizing code for the last branch of non-capturing parentheses,
566        and also for the obeyed branch of a conditional subexpression, which used
567        tail recursion to cut down on stack usage. Unfortunately, now that there is
568        the possibility of (*THEN) occurring in these branches, tail recursion is
569        no longer possible because the return has to be checked for (*THEN). These
570        two optimizations have therefore been removed. [But see 8.20/11 above.]
572    18. If a pattern containing \R was studied, it was assumed that \R always
573        matched two bytes, thus causing the minimum subject length to be
574        incorrectly computed because \R can also match just one byte.
576    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
577        was incorrectly computed.
579    20. If /S is present twice on a test pattern in pcretest input, it now
580        *disables* studying, thereby overriding the use of -s on the command line
581        (see 14 above). This is necessary for one or two tests to keep the output
582        identical in both cases.
584    21. When (*ACCEPT) was used in an assertion that matched an empty string and
585        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
587    22. When an atomic group that contained a capturing parenthesis was
588        successfully matched, but the branch in which it appeared failed, the
589        capturing was not being forgotten if a higher numbered group was later
590        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
591        group 1 to "a", when in fact it should be unset. This applied to multi-
592        branched capturing and non-capturing groups, repeated or not, and also to
593        positive assertions (capturing in negative assertions does not happen
594        in PCRE) and also to nested atomic groups.
596    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
597        subject after a captured substring, to make it easier to tell which of a
598        number of identical substrings has been captured.
600    24. The way atomic groups are processed by pcre_exec() has been changed so that
601        if they are repeated, backtracking one repetition now resets captured
602        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
603        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
604        "aaa". Previously, it would have been "a". As part of this code
605        refactoring, the way recursive calls are handled has also been changed.
607    25. If an assertion condition captured any substrings, they were not passed
608        back unless some other capturing happened later. For example, if
609        (?(?=(a))a) was matched against "a", no capturing was returned.
611    26. When studying a pattern that contained subroutine calls or assertions,
612        the code for finding the minimum length of a possible match was handling
613        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
614        group 1 called group 2 while simultaneously a separate group 2 called group
615        1). A stack overflow occurred in this case. I have fixed this by limiting
616        the recursion depth to 10.
618    27. Updated RunTest.bat in the distribution to the version supplied by Tom
619        Fortmann. This supports explicit test numbers on the command line, and has
620        argument validation and error reporting.
622    28. An instance of \X with an unlimited repeat could fail if at any point the
623        first character it looked at was a mark character.
625    29. Some minor code refactoring concerning Unicode properties and scripts
626        should reduce the stack requirement of match() slightly.
628    30. Added the '=' option to pcretest to check the setting of unused capturing
629        slots at the end of the pattern, which are documented as being -1, but are
630        not included in the return count.
632    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
633        compiled something random. Now it gives a compile-time error (as does
634        Perl).
636    32. A *MARK encountered during the processing of a positive assertion is now
637        recorded and passed back (compatible with Perl).
639    33. If --only-matching or --colour was set on a pcregrep call whose pattern
640        had alternative anchored branches, the search for a second match in a line
641        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
642        matched the line "0102" twice. The same bug affected patterns that started
643        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
644        twice.
646    34. Previously, PCRE did not allow quantification of assertions. However, Perl
647        does, and because of capturing effects, quantifying parenthesized
648        assertions may at times be useful. Quantifiers are now allowed for
649        parenthesized assertions.
651    35. A minor code tidy in pcre_compile() when checking options for \R usage.
653    36. \g was being checked for fancy things in a character class, when it should
654        just be a literal "g".
656    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
657        appearance of a nested POSIX class supersedes an apparent external class.
658        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
659        unescaped square brackets may also appear as part of class names. For
660        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
661        more like Perl. (But see 8.20/1 above.)
663    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
664        was because it thought it was \N{name}, which is not supported).
666    39. Add minix to OS list not supporting the -S option in pcretest.
668    40. PCRE tries to detect cases of infinite recursion at compile time, but it
669        cannot analyze patterns in sufficient detail to catch mutual recursions
670        such as ((?1))((?2)). There is now a runtime test that gives an error if a
671        subgroup is called recursively as a subpattern for a second time at the
672        same position in the subject string. In previous releases this might have
673        been caught by the recursion limit, or it might have run out of stack.
675    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
676        happen only once. PCRE was, however incorrectly giving a compile time error
677        "recursive call could loop indefinitely" because it cannot analyze the
678        pattern in sufficient detail. The compile time test no longer happens when
679        PCRE is compiling a conditional subpattern, but actual runaway loops are
680        now caught at runtime (see 40 above).
682    42. It seems that Perl allows any characters other than a closing parenthesis
683        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
684        has been changed to be the same.
686    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
687        as not to get warnings when autogen.sh is called. Also changed
688        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
690    44. To help people who use pcregrep to scan files containing exceedingly long
691        lines, the following changes have been made:
693        (a) The default value of the buffer size parameter has been increased from
694            8K to 20K. (The actual buffer used is three times this size.)
696        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
697            PCRE is built.
699        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
700            to be set at run time.
702        (d) Numerical values in pcregrep options can be followed by K or M, for
703            example --buffer-size=50K.
705        (e) If a line being scanned overflows pcregrep's buffer, an error is now
706            given and the return code is set to 2.
708    45. Add a pointer to the latest mark to the callout data block.
710    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
711        partial match of an empty string instead of no match. This was specific to
712        the use of ".".
714    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
715        complete match instead of a partial match. This bug was dependent on both
716        the PCRE_UTF8 and PCRE_DOTALL options being set.
718    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
719        starting byte set, because \b was not being ignored.
722    Version 8.12 15-Jan-2011
723    ------------------------
725    1.  Fixed some typos in the markup of the man pages, and wrote a script that
726        checks for such things as part of the documentation building process.
728    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
729        --match-limit and --recursion-limit options (added for 8.11). In
730        particular, this made one of the standard tests fail. (The integer value
731        went into the wrong half of a long int.)
733    3.  If the --colour option was given to pcregrep with -v (invert match), it
734        did strange things, either producing crazy output, or crashing. It should,
735        of course, ignore a request for colour when reporting lines that do not
736        match.
738    4.  Another pcregrep bug caused similar problems if --colour was specified with
739        -M (multiline) and the pattern match finished with a line ending.
741    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
742        matched in multiline mode, the following line was shown as part of the
743        match. This seems wrong, so I have changed it.
745    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
746        the check for further matches in the same line (so they could be coloured)
747        to overrun the end of the current line. If another match was found, it was
748        incorrectly shown (and then shown again when found in the next line).
750    7.  If pcregrep was compiled under Windows, there was a reference to the
751        function pcregrep_exit() before it was defined. I am assuming this was
752        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
753        reported by a user. I've moved the definition above the reference.
756    Version 8.11 10-Dec-2010
757    ------------------------
759    1.  (*THEN) was not working properly if there were untried alternatives prior
760        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
761        backtracked to try for "b" instead of moving to the next alternative branch
762        at the same level (in this case, to look for "c"). The Perl documentation
763        is clear that when (*THEN) is backtracked onto, it goes to the "next
764        alternative in the innermost enclosing group".
766    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
767        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
768        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
769        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
770        (*THEN).
772    3.  If \s appeared in a character class, it removed the VT character from
773        the class, even if it had been included by some previous item, for example
774        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
775        of \s, but is part of the POSIX "space" class.)
777    4.  A partial match never returns an empty string (because you can always
778        match an empty string at the end of the subject); however the checking for
779        an empty string was starting at the "start of match" point. This has been
780        changed to the "earliest inspected character" point, because the returned
781        data for a partial match starts at this character. This means that, for
782        example, /(?<=abc)def/ gives a partial match for the subject "abc"
783        (previously it gave "no match").
785    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
786        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
787        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
788        has an implication that the given string is incomplete (because a partial
789        match is preferred over a full match). For this reason, these items now
790        give a partial match in this situation. [Aside: previously, the one case
791        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
792        match rather than a full match, which was wrong by the old rules, but is
793        now correct.]
795    6.  There was a bug in the handling of #-introduced comments, recognized when
796        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
797        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
798        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
799        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
800        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
801        places in pcre_compile().
803    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
804        comments when looking ahead for named forward references to subpatterns,
805        the only newline sequence it recognized was NL. It now handles newlines
806        according to the set newline convention.
808    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
809        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
810        cater for a lack of strerror(). These oversights have been fixed.
812    9.  Added --match-limit and --recursion-limit to pcregrep.
814    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
816    11. When the -o option was used, pcregrep was setting a return code of 1, even
817        when matches were found, and --line-buffered was not being honoured.
819    12. Added an optional parentheses number to the -o and --only-matching options
820        of pcregrep.
822    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
823        can match an empty string. The code to do it in pcretest and pcredemo
824        needed fixing:
826        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
827            only one byte after an empty string match just before CRLF (this case
828            just got forgotten; "any" and "anycrlf" were OK).
830        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
831            mode when an empty string match preceded an ASCII character followed by
832            a non-ASCII character. (The code for advancing by one character rather
833            than one byte was nonsense.)
835        (c) The pcredemo.c sample program did not have any code at all to handle
836            the cases when CRLF is a valid newline sequence.
838    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
839        as a starting offset was within the subject string. There is now a new
840        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
841        negative or greater than the length of the string. In order to test this,
842        pcretest is extended to allow the setting of negative starting offsets.
844    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
845        starting offset points to the beginning of a UTF-8 character was
846        unnecessarily clumsy. I tidied it up.
848    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
849        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
851    17. Nobody had reported that the --include_dir option, which was added in
852        release 7.7 should have been called --include-dir (hyphen, not underscore)
853        for compatibility with GNU grep. I have changed it to --include-dir, but
854        left --include_dir as an undocumented synonym, and the same for
855        --exclude-dir, though that is not available in GNU grep, at least as of
856        release 2.5.4.
858    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
859        characters from a string of bytes) have been redefined so as not to use
860        loops, in order to improve performance in some environments. At the same
861        time, I abstracted some of the common code into auxiliary macros to save
862        repetition (this should not affect the compiled code).
864    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
865        compile-time error is now given if \c is not followed by an ASCII
866        character, that is, a byte less than 128. (In EBCDIC mode, the code is
867        different, and any byte value is allowed.)
869    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
870        START_OPTIMIZE option, which is now allowed at compile time - but just
871        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
872        to pcregrep and other applications that have no direct access to PCRE
873        options. The new /Y option in pcretest sets this option when calling
874        pcre_compile().
876    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
877        back references. Groups containing recursive back references were forced to
878        be atomic by that change, but in the case of named groups, the amount of
879        memory required was incorrectly computed, leading to "Failed: internal
880        error: code overflow". This has been fixed.
882    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
883        pcretest.c, to avoid build problems in some Borland environments.
886    Version 8.10 25-Jun-2010
887    ------------------------
889    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
890        THEN.
892    2.  (*ACCEPT) was not working when inside an atomic group.
894    3.  Inside a character class, \B is treated as a literal by default, but
895        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
896        causes the error). The code is unchanged, but I tidied the documentation.
898    4.  Inside a character class, PCRE always treated \R and \X as literals,
899        whereas Perl faults them if its -w option is set. I have changed PCRE so
900        that it faults them when PCRE_EXTRA is set.
902    5.  Added support for \N, which always matches any character other than
903        newline. (It is the same as "." when PCRE_DOTALL is not set.)
905    6.  When compiling pcregrep with newer versions of gcc which may have
906        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
907        declared with attribute warn_unused_result" were given. Just casting the
908        result to (void) does not stop the warnings; a more elaborate fudge is
909        needed. I've used a macro to implement this.
911    7.  Minor change to pcretest.c to avoid a compiler warning.
913    8.  Added four artifical Unicode properties to help with an option to make
914        \s etc use properties (see next item). The new properties are: Xan
915        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
917    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
918        use Unicode properties. (*UCP) at the start of a pattern can be used to set
919        this option. Modified pcretest to add /W to test this facility. Added
920        REG_UCP to make it available via the POSIX interface.
922    10. Added --line-buffered to pcregrep.
924    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
925        studied, and the match started with a letter with a code point greater than
926        127 whose first byte was different to the first byte of the other case of
927        the letter, the other case of this starting letter was not recognized
928        (#976).
930    12. If a pattern that was studied started with a repeated Unicode property
931        test, for example, \p{Nd}+, there was the theoretical possibility of
932        setting up an incorrect bitmap of starting bytes, but fortunately it could
933        not have actually happened in practice until change 8 above was made (it
934        added property types that matched character-matching opcodes).
936    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
937        possible starting bytes for non-anchored patterns.
939    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
940        \R, and also a number of cases that involve Unicode properties, both
941        explicit and implicit when PCRE_UCP is set.
943    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
944        input, it could crash or give wrong results if characters with values
945        greater than 0xc0 were present in the subject string. (Detail: it assumed
946        UTF-8 input when processing these items.)
948    16. Added a lot of (int) casts to avoid compiler warnings in systems where
949        size_t is 64-bit (#991).
951    17. Added a check for running out of memory when PCRE is compiled with
952        --disable-stack-for-recursion (#990).
954    18. If the last data line in a file for pcretest does not have a newline on
955        the end, a newline was missing in the output.
957    19. The default pcre_chartables.c file recognizes only ASCII characters (values
958        less than 128) in its various bitmaps. However, there is a facility for
959        generating tables according to the current locale when PCRE is compiled. It
960        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
961        characters, are recognized by isspace() and therefore were getting set in
962        these tables, and indeed these tables seem to approximate to ISO 8859. This
963        caused a problem in UTF-8 mode when pcre_study() was used to create a list
964        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
965        which of course cannot start UTF-8 characters. I have changed the code so
966        that only real ASCII characters (less than 128) and the correct starting
967        bytes for UTF-8 encodings are set for characters greater than 127 when in
968        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
969        altogether.)
971    20. Added the /T option to pcretest so as to be able to run tests with non-
972        standard character tables, thus making it possible to include the tests
973        used for 19 above in the standard set of tests.
975    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
976        reference to a subpattern the other side of a comment that contains an
977        opening parenthesis caused either an internal compiling error, or a
978        reference to the wrong subpattern.
981    Version 8.02 19-Mar-2010
982    ------------------------
984    1.  The Unicode data tables have been updated to Unicode 5.2.0.
986    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
987        configured.
989    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
990        original author of that file, following a query about its status.
992    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
993        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
995    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
996        quantifier applied to a forward-referencing subroutine call, could compile
997        incorrect code or give the error "internal error: previously-checked
998        referenced subpattern not found".
1000    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1001        variables to point to external functions. For these systems, therefore,
1002        pcre_malloc etc. are now initialized to local functions that call the
1003        relevant global functions.
1005    7.  There were two entries missing in the vectors called coptable and poptable
1006        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1007        I've fixed the data, and added a kludgy way of testing at compile time that
1008        the lengths are correct (equal to the number of opcodes).
1010    8.  Following on from 7, I added a similar kludge to check the length of the
1011        eint vector in pcreposix.c.
1013    9.  Error texts for pcre_compile() are held as one long string to avoid too
1014        much relocation at load time. To find a text, the string is searched,
1015        counting zeros. There was no check for running off the end of the string,
1016        which could happen if a new error number was added without updating the
1017        string.
1019    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1021    11. \K was not working if it appeared in an atomic group or in a group that
1022        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1023        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1024        the assertion is positive, but not if it is negative.
1026    12. Change 11 fortuitously reduced the size of the stack frame used in the
1027        "match()" function of pcre_exec.c by one pointer. Forthcoming
1028        implementation of support for (*MARK) will need an extra pointer on the
1029        stack; I have reserved it now, so that the stack frame size does not
1030        decrease.
1032    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1033        item in branch that calls a recursion is a subroutine call - as in the
1034        second branch in the above example - was incorrectly given the compile-
1035        time error "recursive call could loop indefinitely" because pcre_compile()
1036        was not correctly checking the subroutine for matching a non-empty string.
1038    14. The checks for overrunning compiling workspace could trigger after an
1039        overrun had occurred. This is a "should never occur" error, but it can be
1040        triggered by pathological patterns such as hundreds of nested parentheses.
1041        The checks now trigger 100 bytes before the end of the workspace.
1043    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1046    Version 8.01 19-Jan-2010
1047    ------------------------
1049    1.  If a pattern contained a conditional subpattern with only one branch (in
1050        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1051        computed the wrong minimum data length (which is of course zero for such
1052        subpatterns). This could cause incorrect "no match" results.
1054    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1055        the pattern is reset in the first branch, pcre_compile() failed with
1056        "internal error: code overflow at offset...". This happened only when
1057        the reset was to the original external option setting. (An optimization
1058        abstracts leading options settings into an external setting, which was the
1059        cause of this.)
1061    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1062        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1063        assertion pattern did not match (meaning that the assertion was true), it
1064        was incorrectly treated as false if the SKIP had been reached during the
1065        matching. This also applied to assertions used as conditions.
1067    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1068        assertion subpattern, including such a pattern used as a condition,
1069        unpredictable results occurred, instead of the error return
1072    5.  The C++ GlobalReplace function was not working like Perl for the special
1073        situation when an empty string is matched. It now does the fancy magic
1074        stuff that is necessary.
1076    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1077        removed. (These were left over from very, very early versions of PCRE.)
1079    7.  Some cosmetic changes to the code to make life easier when compiling it
1080        as part of something else:
1082        (a) Change DEBUG to PCRE_DEBUG.
1084        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1085            called "current" as "current_branch", to prevent a collision with the
1086            Linux macro when compiled as a kernel module.
1088        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1089            prevent a collision with the Linux macro when compiled as a kernel
1090            module.
1092    8.  In pcre_compile() there are some checks for integer overflows that used to
1093        cast potentially large values to (double). This has been changed to that
1094        when building, a check for int64_t is made, and if it is found, it is used
1095        instead, thus avoiding the use of floating point arithmetic. (There is no
1096        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1097        double.
1099    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1100        2005 (difference between two addresses compared to an unsigned value).
1102    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1103        custom one, because of the following reported problem in Windows:
1105          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1106              under Win32.
1107          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1108              therefore missing the function definition.
1109          - The compiler thus generates a "C" signature for the test function.
1110          - The linker fails to find the "C" function.
1111          - PCRE fails to configure if asked to do so against libbz2.
1113    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1114        messages were output:
1116          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1117          rerunning libtoolize, to keep the correct libtool macros in-tree.
1118          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1120        I have done both of these things.
1122    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1123        most of the time, it *can* run out if it is given a pattern that contains a
1124        runaway infinite recursion. I updated the discussion in the pcrestack man
1125        page.
1127    13. Now that we have gone to the x.xx style of version numbers, the minor
1128        version may start with zero. Using 08 or 09 is a bad idea because users
1129        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1130        interpreted as invalid octal numbers. I've updated the previous comment in
1131        configure.ac, and also added a check that gives an error if 08 or 09 are
1132        used.
1134    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1135        causing partial matching to fail when the end of the subject matched \W
1136        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1138    15. There were some discrepancies between the declarations in pcre_internal.h
1139        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1140        their definitions. The declarations used "const uschar *" and the
1141        definitions used USPTR. Even though USPTR is normally defined as "const
1142        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1143        reported that: "This difference in casting confuses some C++ compilers, for
1144        example, SunCC recognizes above declarations as different functions and
1145        generates broken code for hbpcre." I have changed the declarations to use
1146        USPTR.
1148    16. GNU libtool is named differently on some systems. The autogen.sh script now
1149        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1150        (FreeBSD).
1152    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1153        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1154        comment: "Figure out how to create a longlong from a string: strtoll and
1155        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1156        instance, but it only takes 2 args instead of 3!"
1158    18. A subtle bug concerned with back references has been fixed by a change of
1159        specification, with a corresponding code fix. A pattern such as
1160        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1161        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1162        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1163        same bug. Such groups have to be quantified to be useful, or contained
1164        inside another quantified group. (If there's no repetition, the reference
1165        can never match.) The problem arises because, having left the group and
1166        moved on to the rest of the pattern, a later failure that backtracks into
1167        the group uses the captured value from the final iteration of the group
1168        rather than the correct earlier one. I have fixed this in PCRE by forcing
1169        any group that contains a reference to itself to be an atomic group; that
1170        is, there cannot be any backtracking into it once it has completed. This is
1171        similar to recursive and subroutine calls.
1174    Version 8.00 19-Oct-09
1175    ----------------------
1177    1.  The table for translating pcre_compile() error codes into POSIX error codes
1178        was out-of-date, and there was no check on the pcre_compile() error code
1179        being within the table. This could lead to an OK return being given in
1180        error.
1182    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1183        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1184        in a Windows environment.
1186    3.  The pcregrep --count option prints the count for each file even when it is
1187        zero, as does GNU grep. However, pcregrep was also printing all files when
1188        --files-with-matches was added. Now, when both options are given, it prints
1189        counts only for those files that have at least one match. (GNU grep just
1190        prints the file name in this circumstance, but including the count seems
1191        more useful - otherwise, why use --count?) Also ensured that the
1192        combination -clh just lists non-zero counts, with no names.
1194    4.  The long form of the pcregrep -F option was incorrectly implemented as
1195        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1196        but it seems right to fix it, and I didn't think it was worth preserving
1197        the old behaviour.
1199    5.  The command line items --regex=pattern and --regexp=pattern were not
1200        recognized by pcregrep, which required --regex pattern or --regexp pattern
1201        (with a space rather than an '='). The man page documented the '=' forms,
1202        which are compatible with GNU grep; these now work.
1204    6.  No libpcreposix.pc file was created for pkg-config; there was just
1205        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1207    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1208        when UCP support is not needed, by modifying the Python script that
1209        generates it from Unicode data files. This should not matter if the module
1210        is correctly used as a library, but I received one complaint about 50K of
1211        unwanted data. My guess is that the person linked everything into his
1212        program rather than using a library. Anyway, it does no harm.
1214    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1215        was a minimum greater than 1 for a wide character in a possessive
1216        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1217        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1218        character. Chaos in the form of incorrect output or a compiling loop could
1219        result.
1221    9.  The restrictions on what a pattern can contain when partial matching is
1222        requested for pcre_exec() have been removed. All patterns can now be
1223        partially matched by this function. In addition, if there are at least two
1224        slots in the offset vector, the offset of the earliest inspected character
1225        for the match and the offset of the end of the subject are set in them when
1226        PCRE_ERROR_PARTIAL is returned.
1228    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1229        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1230        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1231        and may be more useful for multi-segment matching.
1233    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1234        used to be given if ever the end of the subject was reached; now it is
1235        given only if matching could not proceed because another character was
1236        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1237        string "Z", which now yields "no match" instead of "partial match". In the
1238        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1239        final character ended with (*FAIL).
1241    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1242        if the pattern had a "must contain" character that was already found in the
1243        earlier partial match, unless partial matching was again requested. For
1244        example, with the pattern /dog.(body)?/, the "must contain" character is
1245        "g". If the first part-match was for the string "dog", restarting with
1246        "sbody" failed. This bug has been fixed.
1248    13. The string returned by pcre_dfa_exec() after a partial match has been
1249        changed so that it starts at the first inspected character rather than the
1250        first character of the match. This makes a difference only if the pattern
1251        starts with a lookbehind assertion or \b or \B (\K is not supported by
1252        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1253        matching functions compatible, and I think it's the right thing to do.
1255    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1256        so that the demonstration program is easily available in environments where
1257        PCRE has not been installed from source.
1259    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1260        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1261        library.
1263    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1264        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1265        is not the first non-POSIX option to be added. Clearly some people find
1266        these options useful.
1268    17. If a caller to the POSIX matching function regexec() passes a non-zero
1269        value for nmatch with a NULL value for pmatch, the value of
1270        nmatch is forced to zero.
1272    18. RunGrepTest did not have a test for the availability of the -u option of
1273        the diff command, as RunTest does. It now checks in the same way as
1274        RunTest, and also checks for the -b option.
1276    19. If an odd number of negated classes containing just a single character
1277        interposed, within parentheses, between a forward reference to a named
1278        subpattern and the definition of the subpattern, compilation crashed with
1279        an internal error, complaining that it could not find the referenced
1280        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1281        [The bug was that it was starting one character too far in when skipping
1282        over the character class, thus treating the ] as data rather than
1283        terminating the class. This meant it could skip too much.]
1285    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1286        /g option in pcretest when the pattern contains \K, which makes it possible
1287        to have an empty string match not at the start, even when the pattern is
1288        anchored. Updated pcretest and pcredemo to use this option.
1290    21. If the maximum number of capturing subpatterns in a recursion was greater
1291        than the maximum at the outer level, the higher number was returned, but
1292        with unset values at the outer level. The correct (outer level) value is
1293        now given.
1295    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1296        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1297        make it do so. The string so far is captured, making this feature
1298        compatible with Perl.
1300    23. The tests have been re-organized, adding tests 11 and 12, to make it
1301        possible to check the Perl 5.10 features against Perl 5.10.
1303    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1304        pattern matches a fixed length string. PCRE did not allow this; now it
1305        does. Neither allows recursion.
1307    25. I finally figured out how to implement a request to provide the minimum
1308        length of subject string that was needed in order to match a given pattern.
1309        (It was back references and recursion that I had previously got hung up
1310        on.) This code has now been added to pcre_study(); it finds a lower bound
1311        to the length of subject needed. It is not necessarily the greatest lower
1312        bound, but using it to avoid searching strings that are too short does give
1313        some useful speed-ups. The value is available to calling programs via
1314        pcre_fullinfo().
1316    26. While implementing 25, I discovered to my embarrassment that pcretest had
1317        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1318        study optimizations had never been tested with that matching function.
1319        Oops. What is worse, even when it was passed study data, there was a bug in
1320        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1321        were also very few tests of studied patterns with pcre_dfa_exec().
1323    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1324        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1325        on the other side of the coin, they are no longer allowed to have different
1326        names, because these cannot be distinguished in PCRE, and this has caused
1327        confusion. (This is a difference from Perl.)
1329    28. When duplicate subpattern names are present (necessarily with different
1330        numbers, as required by 27 above), and a test is made by name in a
1331        conditional pattern, either for a subpattern having been matched, or for
1332        recursion in such a pattern, all the associated numbered subpatterns are
1333        tested, and the overall condition is true if the condition is true for any
1334        one of them. This is the way Perl works, and is also more like the way
1335        testing by number works.
1338    Version 7.9 11-Apr-09
1339    ---------------------
1341    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1342        (pcretest), all targets were linked against these libraries. This included
1343        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1344        libraries. This caused unwanted dependencies to be created. This problem
1345        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1346        pcretest is linked with readline.
1348    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1349        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1350        moved outside it again, because FALSE and TRUE are already defined in AIX,
1351        but BOOL is not.
1353    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1354        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1356    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1357        hyphens) following file names and line numbers when outputting matching
1358        lines. This is not true; no spaces are inserted. I have also clarified the
1359        wording for the --colour (or --color) option.
1361    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1362        was not coloured; this is different to GNU grep, so I have changed it to be
1363        the same.
1365    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1366        each matching line was coloured. Now it goes on to look for further matches
1367        of any of the test patterns, which is the same behaviour as GNU grep.
1369    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1370        doesn't make sense to accept an empty string match in pcregrep, so I have
1371        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1372        seems to be how GNU grep behaves.
1374    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1375        start or after a newline", because the conditional assertion was not being
1376        correctly handled. The rule now is that both the assertion and what follows
1377        in the first alternative must satisfy the test.
1379    9.  If auto-callout was enabled in a pattern with a conditional group whose
1380        condition was an assertion, PCRE could crash during matching, both with
1381        pcre_exec() and pcre_dfa_exec().
1383    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1384        used for matching.
1386    11. Unicode property support in character classes was not working for
1387        characters (bytes) greater than 127 when not in UTF-8 mode.
1389    12. Added the -M command line option to pcretest.
1391    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1393    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1395    16. Added comments and documentation about mis-use of no_arg in the C++
1396        wrapper.
1398    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1399        from Martin Jerabek that uses macro names for all relevant character and
1400        string constants.
1402    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1403        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1404        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1405        these, but not everybody uses configure.
1407    19. A conditional group that had only one branch was not being correctly
1408        recognized as an item that could match an empty string. This meant that an
1409        enclosing group might also not be so recognized, causing infinite looping
1410        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1411        with the subject "ab", where knowledge that the repeated group can match
1412        nothing is needed in order to break the loop.
1414    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1415        exec(), but without supplying a callout function, matching went wrong.
1417    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1418        leak if the size of the offset vector was greater than 30. When the vector
1419        is smaller, the saved offsets during recursion go onto a local stack
1420        vector, but for larger vectors malloc() is used. It was failing to free
1421        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1422        error, in fact).
1424    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1425        heapframe that is used only when UTF-8 support is enabled. This caused no
1426        problem, but was untidy.
1428    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1429        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1430        included within another project.
1432    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1433        slightly modified by me:
1435          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1436              not building pcregrep.
1438          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1439              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1441    25. Forward references, both numeric and by name, in patterns that made use of
1442        duplicate group numbers, could behave incorrectly or give incorrect errors,
1443        because when scanning forward to find the reference group, PCRE was not
1444        taking into account the duplicate group numbers. A pattern such as
1445        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1447    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1448        the feature of a custom pointer more persuasive (as requested by a user).
1450    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1451        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1452        pre-defined.
1454    28. Added support for (*UTF8) at the start of a pattern.
1456    29. Arrange for flags added by the "release type" setting in CMake to be shown
1457        in the configuration summary.
1460    Version 7.8 05-Sep-08
1461    ---------------------
1463    1.  Replaced UCP searching code with optimized version as implemented for Ad
1464        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1465        stage table and inline lookup instead of a function, giving speed ups of 2
1466        to 5 times on some simple patterns that I tested. Permission was given to
1467        distribute the MultiStage2.py script that generates the tables (it's not in
1468        the tarball, but is in the Subversion repository).
1470    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1471        scripts.
1473    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1474        a group with a zero qualifier. The result of the study could be incorrect,
1475        or the function might crash, depending on the pattern.
1477    4.  Caseless matching was not working for non-ASCII characters in back
1478        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1479        It now works when Unicode Property Support is available.
1481    5.  In pcretest, an escape such as \x{de} in the data was always generating
1482        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1483        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1484        truncation.
1486    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1488    7.  Added two (int) casts to pcregrep when printing the difference of two
1489        pointers, in case they are 64-bit values.
1491    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1492        test 2 if it fails.
1494    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1495        and a #define of that name to empty if it is not externally set. This is to
1496        allow users of MSVC to set it if necessary.
1498    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1499        the convenience functions in the pcre_get.c source file.
1501    11. An option change at the start of a pattern that had top-level alternatives
1502        could cause overwriting and/or a crash. This command provoked a crash in
1503        some environments:
1505          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1507        This potential security problem was recorded as CVE-2008-2371.
1509    12. For a pattern where the match had to start at the beginning or immediately
1510        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1511        pcre_dfa_exec() could read past the end of the passed subject if there was
1512        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1513        pcretest so that it places the subject at the end of its malloc-ed buffer.
1515    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1516        exec() might read past the end of the data buffer in UTF-8 mode.
1518    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1519        the data contained the byte 0x85 as part of a UTF-8 character within its
1520        first line. This applied both to normal and DFA matching.
1522    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1523        /^[^d]*?$/8 failed to match "abc".
1525    16. Added a missing copyright notice to pcrecpp_internal.h.
1527    17. Make it more clear in the documentation that values returned from
1528        pcre_exec() in ovector are byte offsets, not character counts.
1530    18. Tidied a few places to stop certain compilers from issuing warnings.
1532    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1533        supplied by Stefan Weber. I made a further small update for 7.8 because
1534        there is a change of source arrangements: the pcre_searchfuncs.c module is
1535        replaced by pcre_ucd.c.
1538    Version 7.7 07-May-08
1539    ---------------------
1541    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1542        a string to a long long, pretend we don't even have a long long." This is
1543        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1545    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1546        pre-7.6 versions, which defined a global no_arg variable instead of putting
1547        it in the RE class. (See also #8 below.)
1549    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1550        Lopes.
1552    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1554        (1) The include/exclude patterns were being applied to the whole pathnames
1555            of files, instead of just to the final components.
1557        (2) If there was more than one level of directory, the subdirectories were
1558            skipped unless they satisfied the include/exclude conditions. This is
1559            inconsistent with GNU grep (and could even be seen as contrary to the
1560            pcregrep specification - which I improved to make it absolutely clear).
1561            The action now is always to scan all levels of directory, and just
1562            apply the include/exclude patterns to regular files.
1564    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1565        --exclude_dir in the tests to avoid scanning .svn directories.
1567    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1568        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1569        doesn't support NULs in patterns.
1571    7.  Added some missing "const"s to declarations of static tables in
1572        pcre_compile.c and pcre_dfa_exec.c.
1574    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1575        caused by fix #2  above. (Subsequently also a second patch to fix the
1576        first patch. And a third patch - this was a messy problem.)
1578    9.  Applied Craig's patch to remove the use of push_back().
1580    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1581        matching function regexec().
1583    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1584        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1585        references. PCRE supports relative numbers with this syntax (I don't think
1586        Oniguruma does).
1588    12. Previously, a group with a zero repeat such as (...){0} was completely
1589        omitted from the compiled regex. However, this means that if the group
1590        was called as a subroutine from elsewhere in the pattern, things went wrong
1591        (an internal error was given). Such groups are now left in the compiled
1592        pattern, with a new opcode that causes them to be skipped at execution
1593        time.
1595    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1596        to the way PCRE behaves:
1598        (a) A lone ] character is dis-allowed (Perl treats it as data).
1600        (b) A back reference to an unmatched subpattern matches an empty string
1601            (Perl fails the current match path).
1603        (c) A data ] in a character class must be notated as \] because if the
1604            first data character in a class is ], it defines an empty class. (In
1605            Perl it is not possible to have an empty class.) The empty class []
1606            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1607            The negative empty class [^] matches any one character, independently
1608            of the DOTALL setting.
1610    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1611        non-existent subpattern following a character class starting with ']' and
1612        containing () gave an internal compiling error instead of "reference to
1613        non-existent subpattern". Fortunately, when the pattern did exist, the
1614        compiled code was correct. (When scanning forwards to check for the
1615        existencd of the subpattern, it was treating the data ']' as terminating
1616        the class, so got the count wrong. When actually compiling, the reference
1617        was subsequently set up correctly.)
1619    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1620        it was being rejected as not supported by pcre_dfa_exec(), even though
1621        other assertions are supported. I have made pcre_dfa_exec() support
1622        (*FAIL).
1624    16. The implementation of 13c above involved the invention of a new opcode,
1625        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1626        cannot be changed at match time, I realized I could make a small
1627        improvement to matching performance by compiling OP_ALLANY instead of
1628        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1629        on the OP_ANY path.
1631    17. Compiling pcretest on Windows with readline support failed without the
1632        following two fixes: (1) Make the unistd.h include conditional on
1633        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1635    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1636        ncurses library to be included for pcretest when ReadLine support is
1637        requested, but also to allow for it to be overridden. This patch came from
1638        Daniel Bergström.
1640    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1641        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1642        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1643        spotting this.
1646    Version 7.6 28-Jan-08
1647  ---------------------  ---------------------
1649  1.  A character class containing a very large number of characters with  1.  A character class containing a very large number of characters with
# Line 23  Version 7.6 21-Jan-08 Line 1665  Version 7.6 21-Jan-08
1665      - Added readline support for pcretest.      - Added readline support for pcretest.
1666      - Added an listing of the option settings after cmake has run.      - Added an listing of the option settings after cmake has run.
1668  4.  A user submitted a patch to Makefile that makes it easy to created a dll  4.  A user submitted a patch to Makefile that makes it easy to create
1669      under mingw. I added stuff to Makefile.am that cause it to include this      "pcre.dll" under mingw when using Configure/Make. I added stuff to
1670      special target, without affecting anything else.      Makefile.am that cause it to include this special target, without
1671        affecting anything else. Note that the same mingw target plus all
1672        the other distribution libraries and programs are now supported
1673        when configuring with CMake (see 6 below) instead of with
1674        Configure/Make.
1676  5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.  5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1677      This is an attempt to solve the reported problem "pcrecpp::no_arg is not      This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1678      exported in the Windows port". It has not yet been confirmed that the patch      exported in the Windows port". It has not yet been confirmed that the patch
1679      solves the problem, but it does no harm.      solves the problem, but it does no harm.
1681  6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and  6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1682      NON_STANDARD_LIB_SUFFIX and correct the comment about stack recursion.      NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1683        with CMake, and also correct the comment about stack recursion.
1685  7.  Remove the automatic building of pcredemo from the ./configure system and  7.  Remove the automatic building of pcredemo from the ./configure system and
1686      from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example      from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1687      of a program that users should build themselves after PCRE is installed, so      of a program that users should build themselves after PCRE is installed, so
1688      building it automatically is not really right. What is more, it gave      building it automatically is not really right. What is more, it gave
1689      trouble in some build environments.      trouble in some build environments.
1691    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1694  Version 7.5 10-Jan-08  Version 7.5 10-Jan-08
1695  ---------------------  ---------------------

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