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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.6 14-Jan-08  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
67    
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    18. Added --file-list option to pcregrep.
71    
72    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
74    
75    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
77    
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
79    
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
82    
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
84    
85    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
86        matches in certain environments (the workspace was not being correctly
87        retained). Also added to pcre_dfa_exec() a simple plausibility check on
88        some of the workspace data at the beginning of a restart.
89    
90    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
91        was not doing so when it should - probably a typo introduced by SVN 528
92        (change 8.10/14).
93    
94    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
95        \w+ when the character tables indicated that \x{c4} was a word character.
96        There were several related cases, all because the tests for doing a table
97        lookup were testing for characters less than 127 instead of 255.
98    
99    27. If a pattern contains capturing parentheses that are not used in a match,
100        their slots in the ovector are set to -1. For those that are higher than
101        any matched groups, this happens at the end of processing. In the case when
102        there were back references that the ovector was too small to contain
103        (causing temporary malloc'd memory to be used during matching), and the
104        highest capturing number was not used, memory off the end of the ovector
105        was incorrectly being set to -1. (It was using the size of the temporary
106        memory instead of the true size.)
107    
108    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
109        ovector size, it uses memory at the end of the block that it has got.
110    
111    29. Check for an overlong MARK name and give an error at compile time. The
112        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
113    
114    
115    Version 8.30 04-February-2012
116    -----------------------------
117    
118    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
119        name is defined in ctype.h.
120    
121    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
122        only in quite long subpatterns.
123    
124    3.  Removed the function pcre_info(), which has been obsolete and deprecated
125        since it was replaced by pcre_fullinfo() in February 2000.
126    
127    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
128        match a (*MARK), and the match failed at the start of the subject, a
129        reference to memory before the start of the subject could occur. This bug
130        was introduced by fix 17 of release 8.21.
131    
132    5.  A reference to an unset group with zero minimum repetition was giving
133        totally wrong answers (in non-JavaScript-compatibility mode). For example,
134        /(another)?(\1?)test/ matched against "hello world test". This bug was
135        introduced in release 8.13.
136    
137    6.  Add support for 16-bit character strings (a large amount of work involving
138        many changes and refactorings).
139    
140    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
141        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
142        from a file.
143    
144    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
145        rounding is not applied in this particular case).
146    
147    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
148        if they appear, or are escaped, in patterns.
149    
150    10. Get rid of a number of -Wunused-but-set-variable warnings.
151    
152    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
153        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
154        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
155        also returns the mark "x". This bug applied to capturing parentheses,
156        non-capturing parentheses, and atomic parentheses. It also applied to some
157        assertions.
158    
159    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
160        information out of configure.ac instead of relying on pcre.h.generic, which
161        is not stored in the repository.
162    
163    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
164        -lreadline.
165    
166    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
167    
168    15. Applied Graycode's patch to put the top-level frame on the stack rather
169        than the heap when not using the stack for recursion. This gives a
170        performance improvement in many cases when recursion is not deep.
171    
172    16. Experimental code added to "pcretest -C" to output the stack frame size.
173    
174    
175    Version 8.21 12-Dec-2011
176    ------------------------
177    
178    1.  Updating the JIT compiler.
179    
180    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
181        are added as well.
182    
183    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
184        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
185        calling _pcre_jit_exec. Some extra comments are added.
186    
187    4.  (*MARK) settings inside atomic groups that do not contain any capturing
188        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
189        was introduced by change 18 for 8.20.
190    
191    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
192        ECMA-262 standard.
193    
194    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
195        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
196        This bug was probably introduced by change 9 of 8.13.
197    
198    7.  While fixing 6 above, I noticed that a number of other items were being
199        incorrectly rejected as "not fixed length". This arose partly because newer
200        opcodes had not been added to the fixed-length checking code. I have (a)
201        corrected the bug and added tests for these items, and (b) arranged for an
202        error to occur if an unknown opcode is encountered while checking for fixed
203        length instead of just assuming "not fixed length". The items that were
204        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
205        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
206        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
207    
208    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
209        being incorrectly compiled and would have given unpredicatble results.
210    
211    9.  A possessively repeated subpattern with minimum repeat count greater than
212        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
213        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
214        the first (A) could occur when it should not.
215    
216    10. Add a cast and remove a redundant test from the code.
217    
218    11. JIT should use pcre_malloc/pcre_free for allocation.
219    
220    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
221        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
222        is anything other than /usr, -L is still shown).
223    
224    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
225    
226    14. Perl does not support \N without a following name in a [] class; PCRE now
227        also gives an error.
228    
229    15. If a forward reference was repeated with an upper limit of around 2000,
230        it caused the error "internal error: overran compiling workspace". The
231        maximum number of forward references (including repeats) was limited by the
232        internal workspace, and dependent on the LINK_SIZE. The code has been
233        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
234        the default depends on LINK_SIZE. There is a new upper limit (for safety)
235        of around 200,000 forward references. While doing this, I also speeded up
236        the filling in of repeated forward references.
237    
238    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
239        incorrectly expecting the subject to contain another "a" after the start.
240    
241    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
242        in the match, the SKIP should be ignored. This was not happening; instead
243        the SKIP was being treated as NOMATCH. For patterns such as
244        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
245        tested.
246    
247    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
248        now much more compatible with Perl, in particular in cases where the result
249        is a non-match for a non-anchored pattern. For example, if
250        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
251        "m", where previously it did not return a name. A side effect of this
252        change is that for partial matches, the last encountered mark name is
253        returned, as for non matches. A number of tests that were previously not
254        Perl-compatible have been moved into the Perl-compatible test files. The
255        refactoring has had the pleasing side effect of removing one argument from
256        the match() function, thus reducing its stack requirements.
257    
258    19. If the /S+ option was used in pcretest to study a pattern using JIT,
259        subsequent uses of /S (without +) incorrectly behaved like /S+.
260    
261    21. Retrieve executable code size support for the JIT compiler and fixing
262        some warnings.
263    
264    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
265        not work when the shorter character appeared right at the end of the
266        subject string.
267    
268    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
269        systems.
270    
271    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
272        output it when the /M option is used in pcretest.
273    
274    25. The CheckMan script was not being included in the distribution. Also, added
275        an explicit "perl" to run Perl scripts from the PrepareRelease script
276        because this is reportedly needed in Windows.
277    
278    26. If study data was being save in a file and studying had not found a set of
279        "starts with" bytes for the pattern, the data written to the file (though
280        never used) was taken from uninitialized memory and so caused valgrind to
281        complain.
282    
283    27. Updated RunTest.bat as provided by Sheri Pierce.
284    
285    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
286    
287    29. Computation of memory usage for the table of capturing group names was
288        giving an unnecessarily large value.
289    
290    
291    Version 8.20 21-Oct-2011
292    ------------------------
293    
294    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
295        a POSIX class. After further experiments with Perl, which convinced me that
296        Perl has bugs and confusions, a closing square bracket is no longer allowed
297        in a POSIX name. This bug also affected patterns with classes that started
298        with full stops.
299    
300    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
301        captured substring, but while checking the failing first alternative,
302        substring 1 is temporarily captured. If the output vector supplied to
303        pcre_exec() was not big enough for this capture, the yield of the function
304        was still zero ("insufficient space for captured substrings"). This cannot
305        be totally fixed without adding another stack variable, which seems a lot
306        of expense for a edge case. However, I have improved the situation in cases
307        such as /(a)(b)x|abc/ matched against "abc", where the return code
308        indicates that fewer than the maximum number of slots in the ovector have
309        been set.
310    
311    3.  Related to (2) above: when there are more back references in a pattern than
312        slots in the output vector, pcre_exec() uses temporary memory during
313        matching, and copies in the captures as far as possible afterwards. It was
314        using the entire output vector, but this conflicts with the specification
315        that only 2/3 is used for passing back captured substrings. Now it uses
316        only the first 2/3, for compatibility. This is, of course, another edge
317        case.
318    
319    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
320        main code base, and can be used by building with --enable-jit. When this is
321        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
322        runtime --no-jit option is given.
323    
324    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
325        ovector, the return from the function was zero, implying that there were
326        other matches that did not fit. The correct "exactly full" value is now
327        returned.
328    
329    6.  If a subpattern that was called recursively or as a subroutine contained
330        (*PRUNE) or any other control that caused it to give a non-standard return,
331        invalid errors such as "Error -26 (nested recursion at the same subject
332        position)" or even infinite loops could occur.
333    
334    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
335        computing the minimum length on reaching *ACCEPT, and so ended up with the
336        wrong value of 1 rather than 0. Further investigation indicates that
337        computing a minimum subject length in the presence of *ACCEPT is difficult
338        (think back references, subroutine calls), and so I have changed the code
339        so that no minimum is registered for a pattern that contains *ACCEPT.
340    
341    8.  If (*THEN) was present in the first (true) branch of a conditional group,
342        it was not handled as intended. [But see 16 below.]
343    
344    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
345        Sheri Pierce.
346    
347    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
348        the first byte in a match must be "a".
349    
350    11. Change 17 for 8.13 increased the recursion depth for patterns like
351        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
352        pattern contains any instances of (*THEN). If it does not, the old
353        optimizations are restored. It would be nice to do this on a per-group
354        basis, but at the moment that is not feasible.
355    
356    12. In some environments, the output of pcretest -C is CRLF terminated. This
357        broke RunTest's code that checks for the link size. A single white space
358        character after the value is now allowed for.
359    
360    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
361        For "fr", it uses the Windows-specific input and output files.
362    
363    14. If (*THEN) appeared in a group that was called recursively or as a
364        subroutine, it did not work as intended. [But see next item.]
365    
366    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
367        pattern fragments (but not containing any | characters). If A and B are
368        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
369        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
370        D. In other words, Perl considers parentheses that do not contain any |
371        characters to be part of a surrounding alternative, whereas PCRE was
372        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
373        differently. PCRE now behaves in the same way as Perl, except in the case
374        of subroutine/recursion calls such as (?1) which have in any case always
375        been different (but PCRE had them first :-).
376    
377    16. Related to 15 above: Perl does not treat the | in a conditional group as
378        creating alternatives. Such a group is treated in the same way as an
379        ordinary group without any | characters when processing (*THEN). PCRE has
380        been changed to match Perl's behaviour.
381    
382    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
383        RunGrepTest script failed.
384    
385    18. Change 22 for version 13 caused atomic groups to use more stack. This is
386        inevitable for groups that contain captures, but it can lead to a lot of
387        stack use in large patterns. The old behaviour has been restored for atomic
388        groups that do not contain any capturing parentheses.
389    
390    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
391        suppress the check for a minimum subject length at run time. (If it was
392        given to pcre_exec() or pcre_dfa_exec() it did work.)
393    
394    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
395        fail to work when decoding hex characters in data strings in EBCDIC
396        environments.
397    
398    21. It appears that in at least one Mac OS environment, the isxdigit() function
399        is implemented as a macro that evaluates to its argument more than once,
400        contravening the C 90 Standard (I haven't checked a later standard). There
401        was an instance in pcretest which caused it to go wrong when processing
402        \x{...} escapes in subject strings. The has been rewritten to avoid using
403        things like p++ in the argument of isxdigit().
404    
405    
406    Version 8.13 16-Aug-2011
407    ------------------------
408    
409    1.  The Unicode data tables have been updated to Unicode 6.0.0.
410    
411    2.  Two minor typos in pcre_internal.h have been fixed.
412    
413    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
414        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
415        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
416    
417    4.  There were a number of related bugs in the code for matching backrefences
418        caselessly in UTF-8 mode when codes for the characters concerned were
419        different numbers of bytes. For example, U+023A and U+2C65 are an upper
420        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
421        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
422        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
423        2-byte code at the end of the subject (it thought there wasn't enough data
424        left).
425    
426    5.  Comprehensive information about what went wrong is now returned by
427        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
428        as the output vector has at least 2 elements. The offset of the start of
429        the failing character and a reason code are placed in the vector.
430    
431    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
432        now returned is for the first byte of the failing character, instead of the
433        last byte inspected. This is an incompatible change, but I hope it is small
434        enough not to be a problem. It makes the returned offset consistent with
435        pcre_exec() and pcre_dfa_exec().
436    
437    7.  pcretest now gives a text phrase as well as the error number when
438        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
439        failure, the offset and reason code are output.
440    
441    8.  When \R was used with a maximizing quantifier it failed to skip backwards
442        over a \r\n pair if the subsequent match failed. Instead, it just skipped
443        back over a single character (\n). This seems wrong (because it treated the
444        two characters as a single entity when going forwards), conflicts with the
445        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
446        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
447        has been changed.
448    
449    9.  Some internal refactoring has changed the processing so that the handling
450        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
451        time (the PCRE_DOTALL option was changed this way some time ago: version
452        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
453        which was always a bit of a fudge. It also means that there is one less
454        argument for the match() function, which reduces its stack requirements
455        slightly. This change also fixes an incompatibility with Perl: the pattern
456        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
457    
458    10. More internal refactoring has drastically reduced the number of recursive
459        calls to match() for possessively repeated groups such as (abc)++ when
460        using pcre_exec().
461    
462    11. While implementing 10, a number of bugs in the handling of groups were
463        discovered and fixed:
464    
465        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
466        (a|)*(?1) gave a compile-time internal error.
467        ((a|)+)+  did not notice that the outer group could match an empty string.
468        (^a|^)+   was not marked as anchored.
469        (.*a|.*)+ was not marked as matching at start or after a newline.
470    
471    12. Yet more internal refactoring has removed another argument from the match()
472        function. Special calls to this function are now indicated by setting a
473        value in a variable in the "match data" data block.
474    
475    13. Be more explicit in pcre_study() instead of relying on "default" for
476        opcodes that mean there is no starting character; this means that when new
477        ones are added and accidentally left out of pcre_study(), testing should
478        pick them up.
479    
480    14. The -s option of pcretest has been documented for ages as being an old
481        synonym of -m (show memory usage). I have changed it to mean "force study
482        for every regex", that is, assume /S for every regex. This is similar to -i
483        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
484        using it. It makes it easier to run collections of tests with and without
485        study enabled, and thereby test pcre_study() more easily. All the standard
486        tests are now run with and without -s (but some patterns can be marked as
487        "never study" - see 20 below).
488    
489    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
490        restoration of the capturing data to the outer values was not happening
491        correctly.
492    
493    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
494        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
495        pattern had matched an empty string, and so incorrectly returned a no
496        match.
497    
498    17. There was optimizing code for the last branch of non-capturing parentheses,
499        and also for the obeyed branch of a conditional subexpression, which used
500        tail recursion to cut down on stack usage. Unfortunately, now that there is
501        the possibility of (*THEN) occurring in these branches, tail recursion is
502        no longer possible because the return has to be checked for (*THEN). These
503        two optimizations have therefore been removed. [But see 8.20/11 above.]
504    
505    18. If a pattern containing \R was studied, it was assumed that \R always
506        matched two bytes, thus causing the minimum subject length to be
507        incorrectly computed because \R can also match just one byte.
508    
509    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
510        was incorrectly computed.
511    
512    20. If /S is present twice on a test pattern in pcretest input, it now
513        *disables* studying, thereby overriding the use of -s on the command line
514        (see 14 above). This is necessary for one or two tests to keep the output
515        identical in both cases.
516    
517    21. When (*ACCEPT) was used in an assertion that matched an empty string and
518        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
519    
520    22. When an atomic group that contained a capturing parenthesis was
521        successfully matched, but the branch in which it appeared failed, the
522        capturing was not being forgotten if a higher numbered group was later
523        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
524        group 1 to "a", when in fact it should be unset. This applied to multi-
525        branched capturing and non-capturing groups, repeated or not, and also to
526        positive assertions (capturing in negative assertions does not happen
527        in PCRE) and also to nested atomic groups.
528    
529    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
530        subject after a captured substring, to make it easier to tell which of a
531        number of identical substrings has been captured.
532    
533    24. The way atomic groups are processed by pcre_exec() has been changed so that
534        if they are repeated, backtracking one repetition now resets captured
535        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
536        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
537        "aaa". Previously, it would have been "a". As part of this code
538        refactoring, the way recursive calls are handled has also been changed.
539    
540    25. If an assertion condition captured any substrings, they were not passed
541        back unless some other capturing happened later. For example, if
542        (?(?=(a))a) was matched against "a", no capturing was returned.
543    
544    26. When studying a pattern that contained subroutine calls or assertions,
545        the code for finding the minimum length of a possible match was handling
546        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
547        group 1 called group 2 while simultaneously a separate group 2 called group
548        1). A stack overflow occurred in this case. I have fixed this by limiting
549        the recursion depth to 10.
550    
551    27. Updated RunTest.bat in the distribution to the version supplied by Tom
552        Fortmann. This supports explicit test numbers on the command line, and has
553        argument validation and error reporting.
554    
555    28. An instance of \X with an unlimited repeat could fail if at any point the
556        first character it looked at was a mark character.
557    
558    29. Some minor code refactoring concerning Unicode properties and scripts
559        should reduce the stack requirement of match() slightly.
560    
561    30. Added the '=' option to pcretest to check the setting of unused capturing
562        slots at the end of the pattern, which are documented as being -1, but are
563        not included in the return count.
564    
565    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
566        compiled something random. Now it gives a compile-time error (as does
567        Perl).
568    
569    32. A *MARK encountered during the processing of a positive assertion is now
570        recorded and passed back (compatible with Perl).
571    
572    33. If --only-matching or --colour was set on a pcregrep call whose pattern
573        had alternative anchored branches, the search for a second match in a line
574        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
575        matched the line "0102" twice. The same bug affected patterns that started
576        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
577        twice.
578    
579    34. Previously, PCRE did not allow quantification of assertions. However, Perl
580        does, and because of capturing effects, quantifying parenthesized
581        assertions may at times be useful. Quantifiers are now allowed for
582        parenthesized assertions.
583    
584    35. A minor code tidy in pcre_compile() when checking options for \R usage.
585    
586    36. \g was being checked for fancy things in a character class, when it should
587        just be a literal "g".
588    
589    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
590        appearance of a nested POSIX class supersedes an apparent external class.
591        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
592        unescaped square brackets may also appear as part of class names. For
593        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
594        more like Perl. (But see 8.20/1 above.)
595    
596    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
597        was because it thought it was \N{name}, which is not supported).
598    
599    39. Add minix to OS list not supporting the -S option in pcretest.
600    
601    40. PCRE tries to detect cases of infinite recursion at compile time, but it
602        cannot analyze patterns in sufficient detail to catch mutual recursions
603        such as ((?1))((?2)). There is now a runtime test that gives an error if a
604        subgroup is called recursively as a subpattern for a second time at the
605        same position in the subject string. In previous releases this might have
606        been caught by the recursion limit, or it might have run out of stack.
607    
608    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
609        happen only once. PCRE was, however incorrectly giving a compile time error
610        "recursive call could loop indefinitely" because it cannot analyze the
611        pattern in sufficient detail. The compile time test no longer happens when
612        PCRE is compiling a conditional subpattern, but actual runaway loops are
613        now caught at runtime (see 40 above).
614    
615    42. It seems that Perl allows any characters other than a closing parenthesis
616        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
617        has been changed to be the same.
618    
619    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
620        as not to get warnings when autogen.sh is called. Also changed
621        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
622    
623    44. To help people who use pcregrep to scan files containing exceedingly long
624        lines, the following changes have been made:
625    
626        (a) The default value of the buffer size parameter has been increased from
627            8K to 20K. (The actual buffer used is three times this size.)
628    
629        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
630            PCRE is built.
631    
632        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
633            to be set at run time.
634    
635        (d) Numerical values in pcregrep options can be followed by K or M, for
636            example --buffer-size=50K.
637    
638        (e) If a line being scanned overflows pcregrep's buffer, an error is now
639            given and the return code is set to 2.
640    
641    45. Add a pointer to the latest mark to the callout data block.
642    
643    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
644        partial match of an empty string instead of no match. This was specific to
645        the use of ".".
646    
647    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
648        complete match instead of a partial match. This bug was dependent on both
649        the PCRE_UTF8 and PCRE_DOTALL options being set.
650    
651    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
652        starting byte set, because \b was not being ignored.
653    
654    
655    Version 8.12 15-Jan-2011
656    ------------------------
657    
658    1.  Fixed some typos in the markup of the man pages, and wrote a script that
659        checks for such things as part of the documentation building process.
660    
661    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
662        --match-limit and --recursion-limit options (added for 8.11). In
663        particular, this made one of the standard tests fail. (The integer value
664        went into the wrong half of a long int.)
665    
666    3.  If the --colour option was given to pcregrep with -v (invert match), it
667        did strange things, either producing crazy output, or crashing. It should,
668        of course, ignore a request for colour when reporting lines that do not
669        match.
670    
671    4.  Another pcregrep bug caused similar problems if --colour was specified with
672        -M (multiline) and the pattern match finished with a line ending.
673    
674    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
675        matched in multiline mode, the following line was shown as part of the
676        match. This seems wrong, so I have changed it.
677    
678    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
679        the check for further matches in the same line (so they could be coloured)
680        to overrun the end of the current line. If another match was found, it was
681        incorrectly shown (and then shown again when found in the next line).
682    
683    7.  If pcregrep was compiled under Windows, there was a reference to the
684        function pcregrep_exit() before it was defined. I am assuming this was
685        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
686        reported by a user. I've moved the definition above the reference.
687    
688    
689    Version 8.11 10-Dec-2010
690    ------------------------
691    
692    1.  (*THEN) was not working properly if there were untried alternatives prior
693        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
694        backtracked to try for "b" instead of moving to the next alternative branch
695        at the same level (in this case, to look for "c"). The Perl documentation
696        is clear that when (*THEN) is backtracked onto, it goes to the "next
697        alternative in the innermost enclosing group".
698    
699    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
700        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
701        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
702        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
703        (*THEN).
704    
705    3.  If \s appeared in a character class, it removed the VT character from
706        the class, even if it had been included by some previous item, for example
707        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
708        of \s, but is part of the POSIX "space" class.)
709    
710    4.  A partial match never returns an empty string (because you can always
711        match an empty string at the end of the subject); however the checking for
712        an empty string was starting at the "start of match" point. This has been
713        changed to the "earliest inspected character" point, because the returned
714        data for a partial match starts at this character. This means that, for
715        example, /(?<=abc)def/ gives a partial match for the subject "abc"
716        (previously it gave "no match").
717    
718    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
719        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
720        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
721        has an implication that the given string is incomplete (because a partial
722        match is preferred over a full match). For this reason, these items now
723        give a partial match in this situation. [Aside: previously, the one case
724        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
725        match rather than a full match, which was wrong by the old rules, but is
726        now correct.]
727    
728    6.  There was a bug in the handling of #-introduced comments, recognized when
729        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
730        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
731        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
732        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
733        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
734        places in pcre_compile().
735    
736    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
737        comments when looking ahead for named forward references to subpatterns,
738        the only newline sequence it recognized was NL. It now handles newlines
739        according to the set newline convention.
740    
741    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
742        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
743        cater for a lack of strerror(). These oversights have been fixed.
744    
745    9.  Added --match-limit and --recursion-limit to pcregrep.
746    
747    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
748    
749    11. When the -o option was used, pcregrep was setting a return code of 1, even
750        when matches were found, and --line-buffered was not being honoured.
751    
752    12. Added an optional parentheses number to the -o and --only-matching options
753        of pcregrep.
754    
755    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
756        can match an empty string. The code to do it in pcretest and pcredemo
757        needed fixing:
758    
759        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
760            only one byte after an empty string match just before CRLF (this case
761            just got forgotten; "any" and "anycrlf" were OK).
762    
763        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
764            mode when an empty string match preceded an ASCII character followed by
765            a non-ASCII character. (The code for advancing by one character rather
766            than one byte was nonsense.)
767    
768        (c) The pcredemo.c sample program did not have any code at all to handle
769            the cases when CRLF is a valid newline sequence.
770    
771    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
772        as a starting offset was within the subject string. There is now a new
773        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
774        negative or greater than the length of the string. In order to test this,
775        pcretest is extended to allow the setting of negative starting offsets.
776    
777    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
778        starting offset points to the beginning of a UTF-8 character was
779        unnecessarily clumsy. I tidied it up.
780    
781    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
782        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
783    
784    17. Nobody had reported that the --include_dir option, which was added in
785        release 7.7 should have been called --include-dir (hyphen, not underscore)
786        for compatibility with GNU grep. I have changed it to --include-dir, but
787        left --include_dir as an undocumented synonym, and the same for
788        --exclude-dir, though that is not available in GNU grep, at least as of
789        release 2.5.4.
790    
791    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
792        characters from a string of bytes) have been redefined so as not to use
793        loops, in order to improve performance in some environments. At the same
794        time, I abstracted some of the common code into auxiliary macros to save
795        repetition (this should not affect the compiled code).
796    
797    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
798        compile-time error is now given if \c is not followed by an ASCII
799        character, that is, a byte less than 128. (In EBCDIC mode, the code is
800        different, and any byte value is allowed.)
801    
802    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
803        START_OPTIMIZE option, which is now allowed at compile time - but just
804        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
805        to pcregrep and other applications that have no direct access to PCRE
806        options. The new /Y option in pcretest sets this option when calling
807        pcre_compile().
808    
809    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
810        back references. Groups containing recursive back references were forced to
811        be atomic by that change, but in the case of named groups, the amount of
812        memory required was incorrectly computed, leading to "Failed: internal
813        error: code overflow". This has been fixed.
814    
815    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
816        pcretest.c, to avoid build problems in some Borland environments.
817    
818    
819    Version 8.10 25-Jun-2010
820    ------------------------
821    
822    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
823        THEN.
824    
825    2.  (*ACCEPT) was not working when inside an atomic group.
826    
827    3.  Inside a character class, \B is treated as a literal by default, but
828        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
829        causes the error). The code is unchanged, but I tidied the documentation.
830    
831    4.  Inside a character class, PCRE always treated \R and \X as literals,
832        whereas Perl faults them if its -w option is set. I have changed PCRE so
833        that it faults them when PCRE_EXTRA is set.
834    
835    5.  Added support for \N, which always matches any character other than
836        newline. (It is the same as "." when PCRE_DOTALL is not set.)
837    
838    6.  When compiling pcregrep with newer versions of gcc which may have
839        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
840        declared with attribute warn_unused_result" were given. Just casting the
841        result to (void) does not stop the warnings; a more elaborate fudge is
842        needed. I've used a macro to implement this.
843    
844    7.  Minor change to pcretest.c to avoid a compiler warning.
845    
846    8.  Added four artifical Unicode properties to help with an option to make
847        \s etc use properties (see next item). The new properties are: Xan
848        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
849    
850    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
851        use Unicode properties. (*UCP) at the start of a pattern can be used to set
852        this option. Modified pcretest to add /W to test this facility. Added
853        REG_UCP to make it available via the POSIX interface.
854    
855    10. Added --line-buffered to pcregrep.
856    
857    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
858        studied, and the match started with a letter with a code point greater than
859        127 whose first byte was different to the first byte of the other case of
860        the letter, the other case of this starting letter was not recognized
861        (#976).
862    
863    12. If a pattern that was studied started with a repeated Unicode property
864        test, for example, \p{Nd}+, there was the theoretical possibility of
865        setting up an incorrect bitmap of starting bytes, but fortunately it could
866        not have actually happened in practice until change 8 above was made (it
867        added property types that matched character-matching opcodes).
868    
869    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
870        possible starting bytes for non-anchored patterns.
871    
872    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
873        \R, and also a number of cases that involve Unicode properties, both
874        explicit and implicit when PCRE_UCP is set.
875    
876    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
877        input, it could crash or give wrong results if characters with values
878        greater than 0xc0 were present in the subject string. (Detail: it assumed
879        UTF-8 input when processing these items.)
880    
881    16. Added a lot of (int) casts to avoid compiler warnings in systems where
882        size_t is 64-bit (#991).
883    
884    17. Added a check for running out of memory when PCRE is compiled with
885        --disable-stack-for-recursion (#990).
886    
887    18. If the last data line in a file for pcretest does not have a newline on
888        the end, a newline was missing in the output.
889    
890    19. The default pcre_chartables.c file recognizes only ASCII characters (values
891        less than 128) in its various bitmaps. However, there is a facility for
892        generating tables according to the current locale when PCRE is compiled. It
893        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
894        characters, are recognized by isspace() and therefore were getting set in
895        these tables, and indeed these tables seem to approximate to ISO 8859. This
896        caused a problem in UTF-8 mode when pcre_study() was used to create a list
897        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
898        which of course cannot start UTF-8 characters. I have changed the code so
899        that only real ASCII characters (less than 128) and the correct starting
900        bytes for UTF-8 encodings are set for characters greater than 127 when in
901        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
902        altogether.)
903    
904    20. Added the /T option to pcretest so as to be able to run tests with non-
905        standard character tables, thus making it possible to include the tests
906        used for 19 above in the standard set of tests.
907    
908    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
909        reference to a subpattern the other side of a comment that contains an
910        opening parenthesis caused either an internal compiling error, or a
911        reference to the wrong subpattern.
912    
913    
914    Version 8.02 19-Mar-2010
915    ------------------------
916    
917    1.  The Unicode data tables have been updated to Unicode 5.2.0.
918    
919    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
920        configured.
921    
922    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
923        original author of that file, following a query about its status.
924    
925    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
926        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
927    
928    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
929        quantifier applied to a forward-referencing subroutine call, could compile
930        incorrect code or give the error "internal error: previously-checked
931        referenced subpattern not found".
932    
933    6.  Both MS Visual Studio and Symbian OS have problems with initializing
934        variables to point to external functions. For these systems, therefore,
935        pcre_malloc etc. are now initialized to local functions that call the
936        relevant global functions.
937    
938    7.  There were two entries missing in the vectors called coptable and poptable
939        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
940        I've fixed the data, and added a kludgy way of testing at compile time that
941        the lengths are correct (equal to the number of opcodes).
942    
943    8.  Following on from 7, I added a similar kludge to check the length of the
944        eint vector in pcreposix.c.
945    
946    9.  Error texts for pcre_compile() are held as one long string to avoid too
947        much relocation at load time. To find a text, the string is searched,
948        counting zeros. There was no check for running off the end of the string,
949        which could happen if a new error number was added without updating the
950        string.
951    
952    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
953    
954    11. \K was not working if it appeared in an atomic group or in a group that
955        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
956        \K is "not well defined" if used in an assertion. PCRE now accepts it if
957        the assertion is positive, but not if it is negative.
958    
959    12. Change 11 fortuitously reduced the size of the stack frame used in the
960        "match()" function of pcre_exec.c by one pointer. Forthcoming
961        implementation of support for (*MARK) will need an extra pointer on the
962        stack; I have reserved it now, so that the stack frame size does not
963        decrease.
964    
965    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
966        item in branch that calls a recursion is a subroutine call - as in the
967        second branch in the above example - was incorrectly given the compile-
968        time error "recursive call could loop indefinitely" because pcre_compile()
969        was not correctly checking the subroutine for matching a non-empty string.
970    
971    14. The checks for overrunning compiling workspace could trigger after an
972        overrun had occurred. This is a "should never occur" error, but it can be
973        triggered by pathological patterns such as hundreds of nested parentheses.
974        The checks now trigger 100 bytes before the end of the workspace.
975    
976    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
977    
978    
979    Version 8.01 19-Jan-2010
980    ------------------------
981    
982    1.  If a pattern contained a conditional subpattern with only one branch (in
983        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
984        computed the wrong minimum data length (which is of course zero for such
985        subpatterns). This could cause incorrect "no match" results.
986    
987    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
988        the pattern is reset in the first branch, pcre_compile() failed with
989        "internal error: code overflow at offset...". This happened only when
990        the reset was to the original external option setting. (An optimization
991        abstracts leading options settings into an external setting, which was the
992        cause of this.)
993    
994    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
995        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
996        assertion pattern did not match (meaning that the assertion was true), it
997        was incorrectly treated as false if the SKIP had been reached during the
998        matching. This also applied to assertions used as conditions.
999    
1000    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1001        assertion subpattern, including such a pattern used as a condition,
1002        unpredictable results occurred, instead of the error return
1003        PCRE_ERROR_DFA_UITEM.
1004    
1005    5.  The C++ GlobalReplace function was not working like Perl for the special
1006        situation when an empty string is matched. It now does the fancy magic
1007        stuff that is necessary.
1008    
1009    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1010        removed. (These were left over from very, very early versions of PCRE.)
1011    
1012    7.  Some cosmetic changes to the code to make life easier when compiling it
1013        as part of something else:
1014    
1015        (a) Change DEBUG to PCRE_DEBUG.
1016    
1017        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1018            called "current" as "current_branch", to prevent a collision with the
1019            Linux macro when compiled as a kernel module.
1020    
1021        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1022            prevent a collision with the Linux macro when compiled as a kernel
1023            module.
1024    
1025    8.  In pcre_compile() there are some checks for integer overflows that used to
1026        cast potentially large values to (double). This has been changed to that
1027        when building, a check for int64_t is made, and if it is found, it is used
1028        instead, thus avoiding the use of floating point arithmetic. (There is no
1029        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1030        double.
1031    
1032    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1033        2005 (difference between two addresses compared to an unsigned value).
1034    
1035    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1036        custom one, because of the following reported problem in Windows:
1037    
1038          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1039              under Win32.
1040          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1041              therefore missing the function definition.
1042          - The compiler thus generates a "C" signature for the test function.
1043          - The linker fails to find the "C" function.
1044          - PCRE fails to configure if asked to do so against libbz2.
1045    
1046    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1047        messages were output:
1048    
1049          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1050          rerunning libtoolize, to keep the correct libtool macros in-tree.
1051          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1052    
1053        I have done both of these things.
1054    
1055    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1056        most of the time, it *can* run out if it is given a pattern that contains a
1057        runaway infinite recursion. I updated the discussion in the pcrestack man
1058        page.
1059    
1060    13. Now that we have gone to the x.xx style of version numbers, the minor
1061        version may start with zero. Using 08 or 09 is a bad idea because users
1062        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1063        interpreted as invalid octal numbers. I've updated the previous comment in
1064        configure.ac, and also added a check that gives an error if 08 or 09 are
1065        used.
1066    
1067    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1068        causing partial matching to fail when the end of the subject matched \W
1069        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1070    
1071    15. There were some discrepancies between the declarations in pcre_internal.h
1072        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1073        their definitions. The declarations used "const uschar *" and the
1074        definitions used USPTR. Even though USPTR is normally defined as "const
1075        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1076        reported that: "This difference in casting confuses some C++ compilers, for
1077        example, SunCC recognizes above declarations as different functions and
1078        generates broken code for hbpcre." I have changed the declarations to use
1079        USPTR.
1080    
1081    16. GNU libtool is named differently on some systems. The autogen.sh script now
1082        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1083        (FreeBSD).
1084    
1085    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1086        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1087        comment: "Figure out how to create a longlong from a string: strtoll and
1088        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1089        instance, but it only takes 2 args instead of 3!"
1090    
1091    18. A subtle bug concerned with back references has been fixed by a change of
1092        specification, with a corresponding code fix. A pattern such as
1093        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1094        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1095        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1096        same bug. Such groups have to be quantified to be useful, or contained
1097        inside another quantified group. (If there's no repetition, the reference
1098        can never match.) The problem arises because, having left the group and
1099        moved on to the rest of the pattern, a later failure that backtracks into
1100        the group uses the captured value from the final iteration of the group
1101        rather than the correct earlier one. I have fixed this in PCRE by forcing
1102        any group that contains a reference to itself to be an atomic group; that
1103        is, there cannot be any backtracking into it once it has completed. This is
1104        similar to recursive and subroutine calls.
1105    
1106    
1107    Version 8.00 19-Oct-09
1108    ----------------------
1109    
1110    1.  The table for translating pcre_compile() error codes into POSIX error codes
1111        was out-of-date, and there was no check on the pcre_compile() error code
1112        being within the table. This could lead to an OK return being given in
1113        error.
1114    
1115    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1116        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1117        in a Windows environment.
1118    
1119    3.  The pcregrep --count option prints the count for each file even when it is
1120        zero, as does GNU grep. However, pcregrep was also printing all files when
1121        --files-with-matches was added. Now, when both options are given, it prints
1122        counts only for those files that have at least one match. (GNU grep just
1123        prints the file name in this circumstance, but including the count seems
1124        more useful - otherwise, why use --count?) Also ensured that the
1125        combination -clh just lists non-zero counts, with no names.
1126    
1127    4.  The long form of the pcregrep -F option was incorrectly implemented as
1128        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1129        but it seems right to fix it, and I didn't think it was worth preserving
1130        the old behaviour.
1131    
1132    5.  The command line items --regex=pattern and --regexp=pattern were not
1133        recognized by pcregrep, which required --regex pattern or --regexp pattern
1134        (with a space rather than an '='). The man page documented the '=' forms,
1135        which are compatible with GNU grep; these now work.
1136    
1137    6.  No libpcreposix.pc file was created for pkg-config; there was just
1138        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1139    
1140    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1141        when UCP support is not needed, by modifying the Python script that
1142        generates it from Unicode data files. This should not matter if the module
1143        is correctly used as a library, but I received one complaint about 50K of
1144        unwanted data. My guess is that the person linked everything into his
1145        program rather than using a library. Anyway, it does no harm.
1146    
1147    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1148        was a minimum greater than 1 for a wide character in a possessive
1149        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1150        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1151        character. Chaos in the form of incorrect output or a compiling loop could
1152        result.
1153    
1154    9.  The restrictions on what a pattern can contain when partial matching is
1155        requested for pcre_exec() have been removed. All patterns can now be
1156        partially matched by this function. In addition, if there are at least two
1157        slots in the offset vector, the offset of the earliest inspected character
1158        for the match and the offset of the end of the subject are set in them when
1159        PCRE_ERROR_PARTIAL is returned.
1160    
1161    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1162        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1163        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1164        and may be more useful for multi-segment matching.
1165    
1166    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1167        used to be given if ever the end of the subject was reached; now it is
1168        given only if matching could not proceed because another character was
1169        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1170        string "Z", which now yields "no match" instead of "partial match". In the
1171        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1172        final character ended with (*FAIL).
1173    
1174    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1175        if the pattern had a "must contain" character that was already found in the
1176        earlier partial match, unless partial matching was again requested. For
1177        example, with the pattern /dog.(body)?/, the "must contain" character is
1178        "g". If the first part-match was for the string "dog", restarting with
1179        "sbody" failed. This bug has been fixed.
1180    
1181    13. The string returned by pcre_dfa_exec() after a partial match has been
1182        changed so that it starts at the first inspected character rather than the
1183        first character of the match. This makes a difference only if the pattern
1184        starts with a lookbehind assertion or \b or \B (\K is not supported by
1185        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1186        matching functions compatible, and I think it's the right thing to do.
1187    
1188    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1189        so that the demonstration program is easily available in environments where
1190        PCRE has not been installed from source.
1191    
1192    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1193        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1194        library.
1195    
1196    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1197        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1198        is not the first non-POSIX option to be added. Clearly some people find
1199        these options useful.
1200    
1201    17. If a caller to the POSIX matching function regexec() passes a non-zero
1202        value for nmatch with a NULL value for pmatch, the value of
1203        nmatch is forced to zero.
1204    
1205    18. RunGrepTest did not have a test for the availability of the -u option of
1206        the diff command, as RunTest does. It now checks in the same way as
1207        RunTest, and also checks for the -b option.
1208    
1209    19. If an odd number of negated classes containing just a single character
1210        interposed, within parentheses, between a forward reference to a named
1211        subpattern and the definition of the subpattern, compilation crashed with
1212        an internal error, complaining that it could not find the referenced
1213        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1214        [The bug was that it was starting one character too far in when skipping
1215        over the character class, thus treating the ] as data rather than
1216        terminating the class. This meant it could skip too much.]
1217    
1218    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1219        /g option in pcretest when the pattern contains \K, which makes it possible
1220        to have an empty string match not at the start, even when the pattern is
1221        anchored. Updated pcretest and pcredemo to use this option.
1222    
1223    21. If the maximum number of capturing subpatterns in a recursion was greater
1224        than the maximum at the outer level, the higher number was returned, but
1225        with unset values at the outer level. The correct (outer level) value is
1226        now given.
1227    
1228    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1229        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1230        make it do so. The string so far is captured, making this feature
1231        compatible with Perl.
1232    
1233    23. The tests have been re-organized, adding tests 11 and 12, to make it
1234        possible to check the Perl 5.10 features against Perl 5.10.
1235    
1236    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1237        pattern matches a fixed length string. PCRE did not allow this; now it
1238        does. Neither allows recursion.
1239    
1240    25. I finally figured out how to implement a request to provide the minimum
1241        length of subject string that was needed in order to match a given pattern.
1242        (It was back references and recursion that I had previously got hung up
1243        on.) This code has now been added to pcre_study(); it finds a lower bound
1244        to the length of subject needed. It is not necessarily the greatest lower
1245        bound, but using it to avoid searching strings that are too short does give
1246        some useful speed-ups. The value is available to calling programs via
1247        pcre_fullinfo().
1248    
1249    26. While implementing 25, I discovered to my embarrassment that pcretest had
1250        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1251        study optimizations had never been tested with that matching function.
1252        Oops. What is worse, even when it was passed study data, there was a bug in
1253        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1254        were also very few tests of studied patterns with pcre_dfa_exec().
1255    
1256    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1257        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1258        on the other side of the coin, they are no longer allowed to have different
1259        names, because these cannot be distinguished in PCRE, and this has caused
1260        confusion. (This is a difference from Perl.)
1261    
1262    28. When duplicate subpattern names are present (necessarily with different
1263        numbers, as required by 27 above), and a test is made by name in a
1264        conditional pattern, either for a subpattern having been matched, or for
1265        recursion in such a pattern, all the associated numbered subpatterns are
1266        tested, and the overall condition is true if the condition is true for any
1267        one of them. This is the way Perl works, and is also more like the way
1268        testing by number works.
1269    
1270    
1271    Version 7.9 11-Apr-09
1272    ---------------------
1273    
1274    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1275        (pcretest), all targets were linked against these libraries. This included
1276        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1277        libraries. This caused unwanted dependencies to be created. This problem
1278        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1279        pcretest is linked with readline.
1280    
1281    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1282        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1283        moved outside it again, because FALSE and TRUE are already defined in AIX,
1284        but BOOL is not.
1285    
1286    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1287        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1288    
1289    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1290        hyphens) following file names and line numbers when outputting matching
1291        lines. This is not true; no spaces are inserted. I have also clarified the
1292        wording for the --colour (or --color) option.
1293    
1294    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1295        was not coloured; this is different to GNU grep, so I have changed it to be
1296        the same.
1297    
1298    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1299        each matching line was coloured. Now it goes on to look for further matches
1300        of any of the test patterns, which is the same behaviour as GNU grep.
1301    
1302    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1303        doesn't make sense to accept an empty string match in pcregrep, so I have
1304        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1305        seems to be how GNU grep behaves.
1306    
1307    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1308        start or after a newline", because the conditional assertion was not being
1309        correctly handled. The rule now is that both the assertion and what follows
1310        in the first alternative must satisfy the test.
1311    
1312    9.  If auto-callout was enabled in a pattern with a conditional group whose
1313        condition was an assertion, PCRE could crash during matching, both with
1314        pcre_exec() and pcre_dfa_exec().
1315    
1316    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1317        used for matching.
1318    
1319    11. Unicode property support in character classes was not working for
1320        characters (bytes) greater than 127 when not in UTF-8 mode.
1321    
1322    12. Added the -M command line option to pcretest.
1323    
1324    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1325    
1326    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1327    
1328    16. Added comments and documentation about mis-use of no_arg in the C++
1329        wrapper.
1330    
1331    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1332        from Martin Jerabek that uses macro names for all relevant character and
1333        string constants.
1334    
1335    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1336        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1337        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1338        these, but not everybody uses configure.
1339    
1340    19. A conditional group that had only one branch was not being correctly
1341        recognized as an item that could match an empty string. This meant that an
1342        enclosing group might also not be so recognized, causing infinite looping
1343        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1344        with the subject "ab", where knowledge that the repeated group can match
1345        nothing is needed in order to break the loop.
1346    
1347    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1348        exec(), but without supplying a callout function, matching went wrong.
1349    
1350    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1351        leak if the size of the offset vector was greater than 30. When the vector
1352        is smaller, the saved offsets during recursion go onto a local stack
1353        vector, but for larger vectors malloc() is used. It was failing to free
1354        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1355        error, in fact).
1356    
1357    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1358        heapframe that is used only when UTF-8 support is enabled. This caused no
1359        problem, but was untidy.
1360    
1361    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1362        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1363        included within another project.
1364    
1365    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1366        slightly modified by me:
1367    
1368          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1369              not building pcregrep.
1370    
1371          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1372              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1373    
1374    25. Forward references, both numeric and by name, in patterns that made use of
1375        duplicate group numbers, could behave incorrectly or give incorrect errors,
1376        because when scanning forward to find the reference group, PCRE was not
1377        taking into account the duplicate group numbers. A pattern such as
1378        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1379    
1380    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1381        the feature of a custom pointer more persuasive (as requested by a user).
1382    
1383    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1384        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1385        pre-defined.
1386    
1387    28. Added support for (*UTF8) at the start of a pattern.
1388    
1389    29. Arrange for flags added by the "release type" setting in CMake to be shown
1390        in the configuration summary.
1391    
1392    
1393    Version 7.8 05-Sep-08
1394  ---------------------  ---------------------
1395    
1396  1.  A class with a very large number of characters with codepoints greater  1.  Replaced UCP searching code with optimized version as implemented for Ad
1397      than 255 (in UTF-8 mode, of course), caused a buffer overflow.      Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1398        stage table and inline lookup instead of a function, giving speed ups of 2
1399        to 5 times on some simple patterns that I tested. Permission was given to
1400        distribute the MultiStage2.py script that generates the tables (it's not in
1401        the tarball, but is in the Subversion repository).
1402    
1403    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1404        scripts.
1405    
1406    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1407        a group with a zero qualifier. The result of the study could be incorrect,
1408        or the function might crash, depending on the pattern.
1409    
1410    4.  Caseless matching was not working for non-ASCII characters in back
1411        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1412        It now works when Unicode Property Support is available.
1413    
1414    5.  In pcretest, an escape such as \x{de} in the data was always generating
1415        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1416        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1417        truncation.
1418    
1419    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1420    
1421    7.  Added two (int) casts to pcregrep when printing the difference of two
1422        pointers, in case they are 64-bit values.
1423    
1424    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1425        test 2 if it fails.
1426    
1427    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1428        and a #define of that name to empty if it is not externally set. This is to
1429        allow users of MSVC to set it if necessary.
1430    
1431    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1432        the convenience functions in the pcre_get.c source file.
1433    
1434    11. An option change at the start of a pattern that had top-level alternatives
1435        could cause overwriting and/or a crash. This command provoked a crash in
1436        some environments:
1437    
1438          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1439    
1440        This potential security problem was recorded as CVE-2008-2371.
1441    
1442    12. For a pattern where the match had to start at the beginning or immediately
1443        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1444        pcre_dfa_exec() could read past the end of the passed subject if there was
1445        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1446        pcretest so that it places the subject at the end of its malloc-ed buffer.
1447    
1448    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1449        exec() might read past the end of the data buffer in UTF-8 mode.
1450    
1451    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1452        the data contained the byte 0x85 as part of a UTF-8 character within its
1453        first line. This applied both to normal and DFA matching.
1454    
1455    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1456        /^[^d]*?$/8 failed to match "abc".
1457    
1458    16. Added a missing copyright notice to pcrecpp_internal.h.
1459    
1460    17. Make it more clear in the documentation that values returned from
1461        pcre_exec() in ovector are byte offsets, not character counts.
1462    
1463    18. Tidied a few places to stop certain compilers from issuing warnings.
1464    
1465    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1466        supplied by Stefan Weber. I made a further small update for 7.8 because
1467        there is a change of source arrangements: the pcre_searchfuncs.c module is
1468        replaced by pcre_ucd.c.
1469    
1470    
1471    Version 7.7 07-May-08
1472    ---------------------
1473    
1474    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1475        a string to a long long, pretend we don't even have a long long." This is
1476        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1477    
1478    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1479        pre-7.6 versions, which defined a global no_arg variable instead of putting
1480        it in the RE class. (See also #8 below.)
1481    
1482    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1483        Lopes.
1484    
1485    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1486    
1487        (1) The include/exclude patterns were being applied to the whole pathnames
1488            of files, instead of just to the final components.
1489    
1490        (2) If there was more than one level of directory, the subdirectories were
1491            skipped unless they satisfied the include/exclude conditions. This is
1492            inconsistent with GNU grep (and could even be seen as contrary to the
1493            pcregrep specification - which I improved to make it absolutely clear).
1494            The action now is always to scan all levels of directory, and just
1495            apply the include/exclude patterns to regular files.
1496    
1497    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1498        --exclude_dir in the tests to avoid scanning .svn directories.
1499    
1500    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1501        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1502        doesn't support NULs in patterns.
1503    
1504    7.  Added some missing "const"s to declarations of static tables in
1505        pcre_compile.c and pcre_dfa_exec.c.
1506    
1507    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1508        caused by fix #2  above. (Subsequently also a second patch to fix the
1509        first patch. And a third patch - this was a messy problem.)
1510    
1511    9.  Applied Craig's patch to remove the use of push_back().
1512    
1513    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1514        matching function regexec().
1515    
1516    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1517        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1518        references. PCRE supports relative numbers with this syntax (I don't think
1519        Oniguruma does).
1520    
1521    12. Previously, a group with a zero repeat such as (...){0} was completely
1522        omitted from the compiled regex. However, this means that if the group
1523        was called as a subroutine from elsewhere in the pattern, things went wrong
1524        (an internal error was given). Such groups are now left in the compiled
1525        pattern, with a new opcode that causes them to be skipped at execution
1526        time.
1527    
1528    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1529        to the way PCRE behaves:
1530    
1531        (a) A lone ] character is dis-allowed (Perl treats it as data).
1532    
1533        (b) A back reference to an unmatched subpattern matches an empty string
1534            (Perl fails the current match path).
1535    
1536        (c) A data ] in a character class must be notated as \] because if the
1537            first data character in a class is ], it defines an empty class. (In
1538            Perl it is not possible to have an empty class.) The empty class []
1539            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1540            The negative empty class [^] matches any one character, independently
1541            of the DOTALL setting.
1542    
1543    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1544        non-existent subpattern following a character class starting with ']' and
1545        containing () gave an internal compiling error instead of "reference to
1546        non-existent subpattern". Fortunately, when the pattern did exist, the
1547        compiled code was correct. (When scanning forwards to check for the
1548        existencd of the subpattern, it was treating the data ']' as terminating
1549        the class, so got the count wrong. When actually compiling, the reference
1550        was subsequently set up correctly.)
1551    
1552    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1553        it was being rejected as not supported by pcre_dfa_exec(), even though
1554        other assertions are supported. I have made pcre_dfa_exec() support
1555        (*FAIL).
1556    
1557    16. The implementation of 13c above involved the invention of a new opcode,
1558        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1559        cannot be changed at match time, I realized I could make a small
1560        improvement to matching performance by compiling OP_ALLANY instead of
1561        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1562        on the OP_ANY path.
1563    
1564    17. Compiling pcretest on Windows with readline support failed without the
1565        following two fixes: (1) Make the unistd.h include conditional on
1566        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1567    
1568    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1569        ncurses library to be included for pcretest when ReadLine support is
1570        requested, but also to allow for it to be overridden. This patch came from
1571        Daniel Bergström.
1572    
1573    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1574        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1575        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1576        spotting this.
1577    
1578    
1579    Version 7.6 28-Jan-08
1580    ---------------------
1581    
1582    1.  A character class containing a very large number of characters with
1583        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1584        overflow.
1585    
1586    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1587        HAVE_LONG_LONG is not defined.
1588    
1589    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1590        bring them up to date and include new features. This patch includes:
1591    
1592        - Fixed PH's badly added libz and libbz2 support.
1593        - Fixed a problem with static linking.
1594        - Added pcredemo. [But later removed - see 7 below.]
1595        - Fixed dftables problem and added an option.
1596        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1597            HAVE_LONG_LONG.
1598        - Added readline support for pcretest.
1599        - Added an listing of the option settings after cmake has run.
1600    
1601    4.  A user submitted a patch to Makefile that makes it easy to create
1602        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1603        Makefile.am that cause it to include this special target, without
1604        affecting anything else. Note that the same mingw target plus all
1605        the other distribution libraries and programs are now supported
1606        when configuring with CMake (see 6 below) instead of with
1607        Configure/Make.
1608    
1609    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1610        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1611        exported in the Windows port". It has not yet been confirmed that the patch
1612        solves the problem, but it does no harm.
1613    
1614    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1615        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1616        with CMake, and also correct the comment about stack recursion.
1617    
1618    7.  Remove the automatic building of pcredemo from the ./configure system and
1619        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1620        of a program that users should build themselves after PCRE is installed, so
1621        building it automatically is not really right. What is more, it gave
1622        trouble in some build environments.
1623    
1624    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1625    
1626    
1627  Version 7.5 10-Jan-08  Version 7.5 10-Jan-08
1628  ---------------------  ---------------------

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