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revision 428 by ph10, Mon Aug 31 17:10:26 2009 UTC revision 977 by zherczeg, Sun Jun 17 06:20:52 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.31 02-June-2012
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    30. JIT compiler update.
115    
116    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
117        Rill for the patch.
118    
119    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
120    
121    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
122    
123    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
124        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
125        was enabled.
126    
127    35. Improve JIT code generation for greedy plus quantifier.
128    
129    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
130        1 to "aa" instead of to an empty string. The bug affected repeated groups
131        that could potentially match an empty string.
132    
133    37. Optimizing single character iterators in JIT.
134    
135    
136    Version 8.30 04-February-2012
137    -----------------------------
138    
139    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
140        name is defined in ctype.h.
141    
142    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
143        only in quite long subpatterns.
144    
145    3.  Removed the function pcre_info(), which has been obsolete and deprecated
146        since it was replaced by pcre_fullinfo() in February 2000.
147    
148    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
149        match a (*MARK), and the match failed at the start of the subject, a
150        reference to memory before the start of the subject could occur. This bug
151        was introduced by fix 17 of release 8.21.
152    
153    5.  A reference to an unset group with zero minimum repetition was giving
154        totally wrong answers (in non-JavaScript-compatibility mode). For example,
155        /(another)?(\1?)test/ matched against "hello world test". This bug was
156        introduced in release 8.13.
157    
158    6.  Add support for 16-bit character strings (a large amount of work involving
159        many changes and refactorings).
160    
161    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
162        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
163        from a file.
164    
165    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
166        rounding is not applied in this particular case).
167    
168    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
169        if they appear, or are escaped, in patterns.
170    
171    10. Get rid of a number of -Wunused-but-set-variable warnings.
172    
173    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
174        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
175        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
176        also returns the mark "x". This bug applied to capturing parentheses,
177        non-capturing parentheses, and atomic parentheses. It also applied to some
178        assertions.
179    
180    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
181        information out of configure.ac instead of relying on pcre.h.generic, which
182        is not stored in the repository.
183    
184    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
185        -lreadline.
186    
187    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
188    
189    15. Applied Graycode's patch to put the top-level frame on the stack rather
190        than the heap when not using the stack for recursion. This gives a
191        performance improvement in many cases when recursion is not deep.
192    
193    16. Experimental code added to "pcretest -C" to output the stack frame size.
194    
195    
196    Version 8.21 12-Dec-2011
197    ------------------------
198    
199    1.  Updating the JIT compiler.
200    
201    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
202        are added as well.
203    
204    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
205        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
206        calling _pcre_jit_exec. Some extra comments are added.
207    
208    4.  (*MARK) settings inside atomic groups that do not contain any capturing
209        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
210        was introduced by change 18 for 8.20.
211    
212    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
213        ECMA-262 standard.
214    
215    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
216        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
217        This bug was probably introduced by change 9 of 8.13.
218    
219    7.  While fixing 6 above, I noticed that a number of other items were being
220        incorrectly rejected as "not fixed length". This arose partly because newer
221        opcodes had not been added to the fixed-length checking code. I have (a)
222        corrected the bug and added tests for these items, and (b) arranged for an
223        error to occur if an unknown opcode is encountered while checking for fixed
224        length instead of just assuming "not fixed length". The items that were
225        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
226        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
227        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
228    
229    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
230        being incorrectly compiled and would have given unpredicatble results.
231    
232    9.  A possessively repeated subpattern with minimum repeat count greater than
233        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
234        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
235        the first (A) could occur when it should not.
236    
237    10. Add a cast and remove a redundant test from the code.
238    
239    11. JIT should use pcre_malloc/pcre_free for allocation.
240    
241    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
242        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
243        is anything other than /usr, -L is still shown).
244    
245    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
246    
247    14. Perl does not support \N without a following name in a [] class; PCRE now
248        also gives an error.
249    
250    15. If a forward reference was repeated with an upper limit of around 2000,
251        it caused the error "internal error: overran compiling workspace". The
252        maximum number of forward references (including repeats) was limited by the
253        internal workspace, and dependent on the LINK_SIZE. The code has been
254        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
255        the default depends on LINK_SIZE. There is a new upper limit (for safety)
256        of around 200,000 forward references. While doing this, I also speeded up
257        the filling in of repeated forward references.
258    
259    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
260        incorrectly expecting the subject to contain another "a" after the start.
261    
262    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
263        in the match, the SKIP should be ignored. This was not happening; instead
264        the SKIP was being treated as NOMATCH. For patterns such as
265        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
266        tested.
267    
268    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
269        now much more compatible with Perl, in particular in cases where the result
270        is a non-match for a non-anchored pattern. For example, if
271        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
272        "m", where previously it did not return a name. A side effect of this
273        change is that for partial matches, the last encountered mark name is
274        returned, as for non matches. A number of tests that were previously not
275        Perl-compatible have been moved into the Perl-compatible test files. The
276        refactoring has had the pleasing side effect of removing one argument from
277        the match() function, thus reducing its stack requirements.
278    
279    19. If the /S+ option was used in pcretest to study a pattern using JIT,
280        subsequent uses of /S (without +) incorrectly behaved like /S+.
281    
282    21. Retrieve executable code size support for the JIT compiler and fixing
283        some warnings.
284    
285    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
286        not work when the shorter character appeared right at the end of the
287        subject string.
288    
289    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
290        systems.
291    
292    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
293        output it when the /M option is used in pcretest.
294    
295    25. The CheckMan script was not being included in the distribution. Also, added
296        an explicit "perl" to run Perl scripts from the PrepareRelease script
297        because this is reportedly needed in Windows.
298    
299    26. If study data was being save in a file and studying had not found a set of
300        "starts with" bytes for the pattern, the data written to the file (though
301        never used) was taken from uninitialized memory and so caused valgrind to
302        complain.
303    
304    27. Updated RunTest.bat as provided by Sheri Pierce.
305    
306    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
307    
308    29. Computation of memory usage for the table of capturing group names was
309        giving an unnecessarily large value.
310    
311    
312    Version 8.20 21-Oct-2011
313    ------------------------
314    
315    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
316        a POSIX class. After further experiments with Perl, which convinced me that
317        Perl has bugs and confusions, a closing square bracket is no longer allowed
318        in a POSIX name. This bug also affected patterns with classes that started
319        with full stops.
320    
321    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
322        captured substring, but while checking the failing first alternative,
323        substring 1 is temporarily captured. If the output vector supplied to
324        pcre_exec() was not big enough for this capture, the yield of the function
325        was still zero ("insufficient space for captured substrings"). This cannot
326        be totally fixed without adding another stack variable, which seems a lot
327        of expense for a edge case. However, I have improved the situation in cases
328        such as /(a)(b)x|abc/ matched against "abc", where the return code
329        indicates that fewer than the maximum number of slots in the ovector have
330        been set.
331    
332    3.  Related to (2) above: when there are more back references in a pattern than
333        slots in the output vector, pcre_exec() uses temporary memory during
334        matching, and copies in the captures as far as possible afterwards. It was
335        using the entire output vector, but this conflicts with the specification
336        that only 2/3 is used for passing back captured substrings. Now it uses
337        only the first 2/3, for compatibility. This is, of course, another edge
338        case.
339    
340    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
341        main code base, and can be used by building with --enable-jit. When this is
342        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
343        runtime --no-jit option is given.
344    
345    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
346        ovector, the return from the function was zero, implying that there were
347        other matches that did not fit. The correct "exactly full" value is now
348        returned.
349    
350    6.  If a subpattern that was called recursively or as a subroutine contained
351        (*PRUNE) or any other control that caused it to give a non-standard return,
352        invalid errors such as "Error -26 (nested recursion at the same subject
353        position)" or even infinite loops could occur.
354    
355    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
356        computing the minimum length on reaching *ACCEPT, and so ended up with the
357        wrong value of 1 rather than 0. Further investigation indicates that
358        computing a minimum subject length in the presence of *ACCEPT is difficult
359        (think back references, subroutine calls), and so I have changed the code
360        so that no minimum is registered for a pattern that contains *ACCEPT.
361    
362    8.  If (*THEN) was present in the first (true) branch of a conditional group,
363        it was not handled as intended. [But see 16 below.]
364    
365    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
366        Sheri Pierce.
367    
368    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
369        the first byte in a match must be "a".
370    
371    11. Change 17 for 8.13 increased the recursion depth for patterns like
372        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
373        pattern contains any instances of (*THEN). If it does not, the old
374        optimizations are restored. It would be nice to do this on a per-group
375        basis, but at the moment that is not feasible.
376    
377    12. In some environments, the output of pcretest -C is CRLF terminated. This
378        broke RunTest's code that checks for the link size. A single white space
379        character after the value is now allowed for.
380    
381    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
382        For "fr", it uses the Windows-specific input and output files.
383    
384    14. If (*THEN) appeared in a group that was called recursively or as a
385        subroutine, it did not work as intended. [But see next item.]
386    
387    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
388        pattern fragments (but not containing any | characters). If A and B are
389        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
390        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
391        D. In other words, Perl considers parentheses that do not contain any |
392        characters to be part of a surrounding alternative, whereas PCRE was
393        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
394        differently. PCRE now behaves in the same way as Perl, except in the case
395        of subroutine/recursion calls such as (?1) which have in any case always
396        been different (but PCRE had them first :-).
397    
398    16. Related to 15 above: Perl does not treat the | in a conditional group as
399        creating alternatives. Such a group is treated in the same way as an
400        ordinary group without any | characters when processing (*THEN). PCRE has
401        been changed to match Perl's behaviour.
402    
403    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
404        RunGrepTest script failed.
405    
406    18. Change 22 for version 13 caused atomic groups to use more stack. This is
407        inevitable for groups that contain captures, but it can lead to a lot of
408        stack use in large patterns. The old behaviour has been restored for atomic
409        groups that do not contain any capturing parentheses.
410    
411    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
412        suppress the check for a minimum subject length at run time. (If it was
413        given to pcre_exec() or pcre_dfa_exec() it did work.)
414    
415    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
416        fail to work when decoding hex characters in data strings in EBCDIC
417        environments.
418    
419    21. It appears that in at least one Mac OS environment, the isxdigit() function
420        is implemented as a macro that evaluates to its argument more than once,
421        contravening the C 90 Standard (I haven't checked a later standard). There
422        was an instance in pcretest which caused it to go wrong when processing
423        \x{...} escapes in subject strings. The has been rewritten to avoid using
424        things like p++ in the argument of isxdigit().
425    
426    
427    Version 8.13 16-Aug-2011
428    ------------------------
429    
430    1.  The Unicode data tables have been updated to Unicode 6.0.0.
431    
432    2.  Two minor typos in pcre_internal.h have been fixed.
433    
434    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
435        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
436        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
437    
438    4.  There were a number of related bugs in the code for matching backrefences
439        caselessly in UTF-8 mode when codes for the characters concerned were
440        different numbers of bytes. For example, U+023A and U+2C65 are an upper
441        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
442        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
443        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
444        2-byte code at the end of the subject (it thought there wasn't enough data
445        left).
446    
447    5.  Comprehensive information about what went wrong is now returned by
448        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
449        as the output vector has at least 2 elements. The offset of the start of
450        the failing character and a reason code are placed in the vector.
451    
452    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
453        now returned is for the first byte of the failing character, instead of the
454        last byte inspected. This is an incompatible change, but I hope it is small
455        enough not to be a problem. It makes the returned offset consistent with
456        pcre_exec() and pcre_dfa_exec().
457    
458    7.  pcretest now gives a text phrase as well as the error number when
459        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
460        failure, the offset and reason code are output.
461    
462    8.  When \R was used with a maximizing quantifier it failed to skip backwards
463        over a \r\n pair if the subsequent match failed. Instead, it just skipped
464        back over a single character (\n). This seems wrong (because it treated the
465        two characters as a single entity when going forwards), conflicts with the
466        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
467        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
468        has been changed.
469    
470    9.  Some internal refactoring has changed the processing so that the handling
471        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
472        time (the PCRE_DOTALL option was changed this way some time ago: version
473        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
474        which was always a bit of a fudge. It also means that there is one less
475        argument for the match() function, which reduces its stack requirements
476        slightly. This change also fixes an incompatibility with Perl: the pattern
477        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
478    
479    10. More internal refactoring has drastically reduced the number of recursive
480        calls to match() for possessively repeated groups such as (abc)++ when
481        using pcre_exec().
482    
483    11. While implementing 10, a number of bugs in the handling of groups were
484        discovered and fixed:
485    
486        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
487        (a|)*(?1) gave a compile-time internal error.
488        ((a|)+)+  did not notice that the outer group could match an empty string.
489        (^a|^)+   was not marked as anchored.
490        (.*a|.*)+ was not marked as matching at start or after a newline.
491    
492    12. Yet more internal refactoring has removed another argument from the match()
493        function. Special calls to this function are now indicated by setting a
494        value in a variable in the "match data" data block.
495    
496    13. Be more explicit in pcre_study() instead of relying on "default" for
497        opcodes that mean there is no starting character; this means that when new
498        ones are added and accidentally left out of pcre_study(), testing should
499        pick them up.
500    
501    14. The -s option of pcretest has been documented for ages as being an old
502        synonym of -m (show memory usage). I have changed it to mean "force study
503        for every regex", that is, assume /S for every regex. This is similar to -i
504        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
505        using it. It makes it easier to run collections of tests with and without
506        study enabled, and thereby test pcre_study() more easily. All the standard
507        tests are now run with and without -s (but some patterns can be marked as
508        "never study" - see 20 below).
509    
510    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
511        restoration of the capturing data to the outer values was not happening
512        correctly.
513    
514    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
515        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
516        pattern had matched an empty string, and so incorrectly returned a no
517        match.
518    
519    17. There was optimizing code for the last branch of non-capturing parentheses,
520        and also for the obeyed branch of a conditional subexpression, which used
521        tail recursion to cut down on stack usage. Unfortunately, now that there is
522        the possibility of (*THEN) occurring in these branches, tail recursion is
523        no longer possible because the return has to be checked for (*THEN). These
524        two optimizations have therefore been removed. [But see 8.20/11 above.]
525    
526    18. If a pattern containing \R was studied, it was assumed that \R always
527        matched two bytes, thus causing the minimum subject length to be
528        incorrectly computed because \R can also match just one byte.
529    
530    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
531        was incorrectly computed.
532    
533    20. If /S is present twice on a test pattern in pcretest input, it now
534        *disables* studying, thereby overriding the use of -s on the command line
535        (see 14 above). This is necessary for one or two tests to keep the output
536        identical in both cases.
537    
538    21. When (*ACCEPT) was used in an assertion that matched an empty string and
539        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
540    
541    22. When an atomic group that contained a capturing parenthesis was
542        successfully matched, but the branch in which it appeared failed, the
543        capturing was not being forgotten if a higher numbered group was later
544        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
545        group 1 to "a", when in fact it should be unset. This applied to multi-
546        branched capturing and non-capturing groups, repeated or not, and also to
547        positive assertions (capturing in negative assertions does not happen
548        in PCRE) and also to nested atomic groups.
549    
550    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
551        subject after a captured substring, to make it easier to tell which of a
552        number of identical substrings has been captured.
553    
554    24. The way atomic groups are processed by pcre_exec() has been changed so that
555        if they are repeated, backtracking one repetition now resets captured
556        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
557        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
558        "aaa". Previously, it would have been "a". As part of this code
559        refactoring, the way recursive calls are handled has also been changed.
560    
561    25. If an assertion condition captured any substrings, they were not passed
562        back unless some other capturing happened later. For example, if
563        (?(?=(a))a) was matched against "a", no capturing was returned.
564    
565    26. When studying a pattern that contained subroutine calls or assertions,
566        the code for finding the minimum length of a possible match was handling
567        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
568        group 1 called group 2 while simultaneously a separate group 2 called group
569        1). A stack overflow occurred in this case. I have fixed this by limiting
570        the recursion depth to 10.
571    
572    27. Updated RunTest.bat in the distribution to the version supplied by Tom
573        Fortmann. This supports explicit test numbers on the command line, and has
574        argument validation and error reporting.
575    
576    28. An instance of \X with an unlimited repeat could fail if at any point the
577        first character it looked at was a mark character.
578    
579    29. Some minor code refactoring concerning Unicode properties and scripts
580        should reduce the stack requirement of match() slightly.
581    
582    30. Added the '=' option to pcretest to check the setting of unused capturing
583        slots at the end of the pattern, which are documented as being -1, but are
584        not included in the return count.
585    
586    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
587        compiled something random. Now it gives a compile-time error (as does
588        Perl).
589    
590    32. A *MARK encountered during the processing of a positive assertion is now
591        recorded and passed back (compatible with Perl).
592    
593    33. If --only-matching or --colour was set on a pcregrep call whose pattern
594        had alternative anchored branches, the search for a second match in a line
595        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
596        matched the line "0102" twice. The same bug affected patterns that started
597        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
598        twice.
599    
600    34. Previously, PCRE did not allow quantification of assertions. However, Perl
601        does, and because of capturing effects, quantifying parenthesized
602        assertions may at times be useful. Quantifiers are now allowed for
603        parenthesized assertions.
604    
605    35. A minor code tidy in pcre_compile() when checking options for \R usage.
606    
607    36. \g was being checked for fancy things in a character class, when it should
608        just be a literal "g".
609    
610    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
611        appearance of a nested POSIX class supersedes an apparent external class.
612        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
613        unescaped square brackets may also appear as part of class names. For
614        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
615        more like Perl. (But see 8.20/1 above.)
616    
617    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
618        was because it thought it was \N{name}, which is not supported).
619    
620    39. Add minix to OS list not supporting the -S option in pcretest.
621    
622    40. PCRE tries to detect cases of infinite recursion at compile time, but it
623        cannot analyze patterns in sufficient detail to catch mutual recursions
624        such as ((?1))((?2)). There is now a runtime test that gives an error if a
625        subgroup is called recursively as a subpattern for a second time at the
626        same position in the subject string. In previous releases this might have
627        been caught by the recursion limit, or it might have run out of stack.
628    
629    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
630        happen only once. PCRE was, however incorrectly giving a compile time error
631        "recursive call could loop indefinitely" because it cannot analyze the
632        pattern in sufficient detail. The compile time test no longer happens when
633        PCRE is compiling a conditional subpattern, but actual runaway loops are
634        now caught at runtime (see 40 above).
635    
636    42. It seems that Perl allows any characters other than a closing parenthesis
637        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
638        has been changed to be the same.
639    
640    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
641        as not to get warnings when autogen.sh is called. Also changed
642        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
643    
644    44. To help people who use pcregrep to scan files containing exceedingly long
645        lines, the following changes have been made:
646    
647        (a) The default value of the buffer size parameter has been increased from
648            8K to 20K. (The actual buffer used is three times this size.)
649    
650        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
651            PCRE is built.
652    
653        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
654            to be set at run time.
655    
656        (d) Numerical values in pcregrep options can be followed by K or M, for
657            example --buffer-size=50K.
658    
659        (e) If a line being scanned overflows pcregrep's buffer, an error is now
660            given and the return code is set to 2.
661    
662    45. Add a pointer to the latest mark to the callout data block.
663    
664    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
665        partial match of an empty string instead of no match. This was specific to
666        the use of ".".
667    
668    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
669        complete match instead of a partial match. This bug was dependent on both
670        the PCRE_UTF8 and PCRE_DOTALL options being set.
671    
672    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
673        starting byte set, because \b was not being ignored.
674    
675    
676    Version 8.12 15-Jan-2011
677    ------------------------
678    
679    1.  Fixed some typos in the markup of the man pages, and wrote a script that
680        checks for such things as part of the documentation building process.
681    
682    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
683        --match-limit and --recursion-limit options (added for 8.11). In
684        particular, this made one of the standard tests fail. (The integer value
685        went into the wrong half of a long int.)
686    
687    3.  If the --colour option was given to pcregrep with -v (invert match), it
688        did strange things, either producing crazy output, or crashing. It should,
689        of course, ignore a request for colour when reporting lines that do not
690        match.
691    
692    4.  Another pcregrep bug caused similar problems if --colour was specified with
693        -M (multiline) and the pattern match finished with a line ending.
694    
695    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
696        matched in multiline mode, the following line was shown as part of the
697        match. This seems wrong, so I have changed it.
698    
699    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
700        the check for further matches in the same line (so they could be coloured)
701        to overrun the end of the current line. If another match was found, it was
702        incorrectly shown (and then shown again when found in the next line).
703    
704    7.  If pcregrep was compiled under Windows, there was a reference to the
705        function pcregrep_exit() before it was defined. I am assuming this was
706        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
707        reported by a user. I've moved the definition above the reference.
708    
709    
710    Version 8.11 10-Dec-2010
711    ------------------------
712    
713    1.  (*THEN) was not working properly if there were untried alternatives prior
714        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
715        backtracked to try for "b" instead of moving to the next alternative branch
716        at the same level (in this case, to look for "c"). The Perl documentation
717        is clear that when (*THEN) is backtracked onto, it goes to the "next
718        alternative in the innermost enclosing group".
719    
720    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
721        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
722        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
723        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
724        (*THEN).
725    
726    3.  If \s appeared in a character class, it removed the VT character from
727        the class, even if it had been included by some previous item, for example
728        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
729        of \s, but is part of the POSIX "space" class.)
730    
731    4.  A partial match never returns an empty string (because you can always
732        match an empty string at the end of the subject); however the checking for
733        an empty string was starting at the "start of match" point. This has been
734        changed to the "earliest inspected character" point, because the returned
735        data for a partial match starts at this character. This means that, for
736        example, /(?<=abc)def/ gives a partial match for the subject "abc"
737        (previously it gave "no match").
738    
739    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
740        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
741        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
742        has an implication that the given string is incomplete (because a partial
743        match is preferred over a full match). For this reason, these items now
744        give a partial match in this situation. [Aside: previously, the one case
745        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
746        match rather than a full match, which was wrong by the old rules, but is
747        now correct.]
748    
749    6.  There was a bug in the handling of #-introduced comments, recognized when
750        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
751        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
752        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
753        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
754        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
755        places in pcre_compile().
756    
757    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
758        comments when looking ahead for named forward references to subpatterns,
759        the only newline sequence it recognized was NL. It now handles newlines
760        according to the set newline convention.
761    
762    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
763        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
764        cater for a lack of strerror(). These oversights have been fixed.
765    
766    9.  Added --match-limit and --recursion-limit to pcregrep.
767    
768    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
769    
770    11. When the -o option was used, pcregrep was setting a return code of 1, even
771        when matches were found, and --line-buffered was not being honoured.
772    
773    12. Added an optional parentheses number to the -o and --only-matching options
774        of pcregrep.
775    
776    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
777        can match an empty string. The code to do it in pcretest and pcredemo
778        needed fixing:
779    
780        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
781            only one byte after an empty string match just before CRLF (this case
782            just got forgotten; "any" and "anycrlf" were OK).
783    
784        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
785            mode when an empty string match preceded an ASCII character followed by
786            a non-ASCII character. (The code for advancing by one character rather
787            than one byte was nonsense.)
788    
789        (c) The pcredemo.c sample program did not have any code at all to handle
790            the cases when CRLF is a valid newline sequence.
791    
792    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
793        as a starting offset was within the subject string. There is now a new
794        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
795        negative or greater than the length of the string. In order to test this,
796        pcretest is extended to allow the setting of negative starting offsets.
797    
798    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
799        starting offset points to the beginning of a UTF-8 character was
800        unnecessarily clumsy. I tidied it up.
801    
802    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
803        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
804    
805    17. Nobody had reported that the --include_dir option, which was added in
806        release 7.7 should have been called --include-dir (hyphen, not underscore)
807        for compatibility with GNU grep. I have changed it to --include-dir, but
808        left --include_dir as an undocumented synonym, and the same for
809        --exclude-dir, though that is not available in GNU grep, at least as of
810        release 2.5.4.
811    
812    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
813        characters from a string of bytes) have been redefined so as not to use
814        loops, in order to improve performance in some environments. At the same
815        time, I abstracted some of the common code into auxiliary macros to save
816        repetition (this should not affect the compiled code).
817    
818    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
819        compile-time error is now given if \c is not followed by an ASCII
820        character, that is, a byte less than 128. (In EBCDIC mode, the code is
821        different, and any byte value is allowed.)
822    
823    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
824        START_OPTIMIZE option, which is now allowed at compile time - but just
825        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
826        to pcregrep and other applications that have no direct access to PCRE
827        options. The new /Y option in pcretest sets this option when calling
828        pcre_compile().
829    
830    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
831        back references. Groups containing recursive back references were forced to
832        be atomic by that change, but in the case of named groups, the amount of
833        memory required was incorrectly computed, leading to "Failed: internal
834        error: code overflow". This has been fixed.
835    
836    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
837        pcretest.c, to avoid build problems in some Borland environments.
838    
839    
840    Version 8.10 25-Jun-2010
841    ------------------------
842    
843    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
844        THEN.
845    
846    2.  (*ACCEPT) was not working when inside an atomic group.
847    
848    3.  Inside a character class, \B is treated as a literal by default, but
849        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
850        causes the error). The code is unchanged, but I tidied the documentation.
851    
852    4.  Inside a character class, PCRE always treated \R and \X as literals,
853        whereas Perl faults them if its -w option is set. I have changed PCRE so
854        that it faults them when PCRE_EXTRA is set.
855    
856    5.  Added support for \N, which always matches any character other than
857        newline. (It is the same as "." when PCRE_DOTALL is not set.)
858    
859    6.  When compiling pcregrep with newer versions of gcc which may have
860        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
861        declared with attribute warn_unused_result" were given. Just casting the
862        result to (void) does not stop the warnings; a more elaborate fudge is
863        needed. I've used a macro to implement this.
864    
865    7.  Minor change to pcretest.c to avoid a compiler warning.
866    
867    8.  Added four artifical Unicode properties to help with an option to make
868        \s etc use properties (see next item). The new properties are: Xan
869        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
870    
871    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
872        use Unicode properties. (*UCP) at the start of a pattern can be used to set
873        this option. Modified pcretest to add /W to test this facility. Added
874        REG_UCP to make it available via the POSIX interface.
875    
876    10. Added --line-buffered to pcregrep.
877    
878    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
879        studied, and the match started with a letter with a code point greater than
880        127 whose first byte was different to the first byte of the other case of
881        the letter, the other case of this starting letter was not recognized
882        (#976).
883    
884    12. If a pattern that was studied started with a repeated Unicode property
885        test, for example, \p{Nd}+, there was the theoretical possibility of
886        setting up an incorrect bitmap of starting bytes, but fortunately it could
887        not have actually happened in practice until change 8 above was made (it
888        added property types that matched character-matching opcodes).
889    
890    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
891        possible starting bytes for non-anchored patterns.
892    
893    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
894        \R, and also a number of cases that involve Unicode properties, both
895        explicit and implicit when PCRE_UCP is set.
896    
897    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
898        input, it could crash or give wrong results if characters with values
899        greater than 0xc0 were present in the subject string. (Detail: it assumed
900        UTF-8 input when processing these items.)
901    
902    16. Added a lot of (int) casts to avoid compiler warnings in systems where
903        size_t is 64-bit (#991).
904    
905    17. Added a check for running out of memory when PCRE is compiled with
906        --disable-stack-for-recursion (#990).
907    
908    18. If the last data line in a file for pcretest does not have a newline on
909        the end, a newline was missing in the output.
910    
911    19. The default pcre_chartables.c file recognizes only ASCII characters (values
912        less than 128) in its various bitmaps. However, there is a facility for
913        generating tables according to the current locale when PCRE is compiled. It
914        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
915        characters, are recognized by isspace() and therefore were getting set in
916        these tables, and indeed these tables seem to approximate to ISO 8859. This
917        caused a problem in UTF-8 mode when pcre_study() was used to create a list
918        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
919        which of course cannot start UTF-8 characters. I have changed the code so
920        that only real ASCII characters (less than 128) and the correct starting
921        bytes for UTF-8 encodings are set for characters greater than 127 when in
922        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
923        altogether.)
924    
925    20. Added the /T option to pcretest so as to be able to run tests with non-
926        standard character tables, thus making it possible to include the tests
927        used for 19 above in the standard set of tests.
928    
929    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
930        reference to a subpattern the other side of a comment that contains an
931        opening parenthesis caused either an internal compiling error, or a
932        reference to the wrong subpattern.
933    
934    
935    Version 8.02 19-Mar-2010
936    ------------------------
937    
938    1.  The Unicode data tables have been updated to Unicode 5.2.0.
939    
940    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
941        configured.
942    
943    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
944        original author of that file, following a query about its status.
945    
946    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
947        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
948    
949    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
950        quantifier applied to a forward-referencing subroutine call, could compile
951        incorrect code or give the error "internal error: previously-checked
952        referenced subpattern not found".
953    
954    6.  Both MS Visual Studio and Symbian OS have problems with initializing
955        variables to point to external functions. For these systems, therefore,
956        pcre_malloc etc. are now initialized to local functions that call the
957        relevant global functions.
958    
959    7.  There were two entries missing in the vectors called coptable and poptable
960        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
961        I've fixed the data, and added a kludgy way of testing at compile time that
962        the lengths are correct (equal to the number of opcodes).
963    
964    8.  Following on from 7, I added a similar kludge to check the length of the
965        eint vector in pcreposix.c.
966    
967    9.  Error texts for pcre_compile() are held as one long string to avoid too
968        much relocation at load time. To find a text, the string is searched,
969        counting zeros. There was no check for running off the end of the string,
970        which could happen if a new error number was added without updating the
971        string.
972    
973    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
974    
975    11. \K was not working if it appeared in an atomic group or in a group that
976        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
977        \K is "not well defined" if used in an assertion. PCRE now accepts it if
978        the assertion is positive, but not if it is negative.
979    
980    12. Change 11 fortuitously reduced the size of the stack frame used in the
981        "match()" function of pcre_exec.c by one pointer. Forthcoming
982        implementation of support for (*MARK) will need an extra pointer on the
983        stack; I have reserved it now, so that the stack frame size does not
984        decrease.
985    
986    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
987        item in branch that calls a recursion is a subroutine call - as in the
988        second branch in the above example - was incorrectly given the compile-
989        time error "recursive call could loop indefinitely" because pcre_compile()
990        was not correctly checking the subroutine for matching a non-empty string.
991    
992    14. The checks for overrunning compiling workspace could trigger after an
993        overrun had occurred. This is a "should never occur" error, but it can be
994        triggered by pathological patterns such as hundreds of nested parentheses.
995        The checks now trigger 100 bytes before the end of the workspace.
996    
997    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
998    
999    
1000    Version 8.01 19-Jan-2010
1001    ------------------------
1002    
1003    1.  If a pattern contained a conditional subpattern with only one branch (in
1004        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1005        computed the wrong minimum data length (which is of course zero for such
1006        subpatterns). This could cause incorrect "no match" results.
1007    
1008    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1009        the pattern is reset in the first branch, pcre_compile() failed with
1010        "internal error: code overflow at offset...". This happened only when
1011        the reset was to the original external option setting. (An optimization
1012        abstracts leading options settings into an external setting, which was the
1013        cause of this.)
1014    
1015    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1016        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1017        assertion pattern did not match (meaning that the assertion was true), it
1018        was incorrectly treated as false if the SKIP had been reached during the
1019        matching. This also applied to assertions used as conditions.
1020    
1021    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1022        assertion subpattern, including such a pattern used as a condition,
1023        unpredictable results occurred, instead of the error return
1024        PCRE_ERROR_DFA_UITEM.
1025    
1026    5.  The C++ GlobalReplace function was not working like Perl for the special
1027        situation when an empty string is matched. It now does the fancy magic
1028        stuff that is necessary.
1029    
1030    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1031        removed. (These were left over from very, very early versions of PCRE.)
1032    
1033    7.  Some cosmetic changes to the code to make life easier when compiling it
1034        as part of something else:
1035    
1036        (a) Change DEBUG to PCRE_DEBUG.
1037    
1038        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1039            called "current" as "current_branch", to prevent a collision with the
1040            Linux macro when compiled as a kernel module.
1041    
1042        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1043            prevent a collision with the Linux macro when compiled as a kernel
1044            module.
1045    
1046    8.  In pcre_compile() there are some checks for integer overflows that used to
1047        cast potentially large values to (double). This has been changed to that
1048        when building, a check for int64_t is made, and if it is found, it is used
1049        instead, thus avoiding the use of floating point arithmetic. (There is no
1050        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1051        double.
1052    
1053    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1054        2005 (difference between two addresses compared to an unsigned value).
1055    
1056    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1057        custom one, because of the following reported problem in Windows:
1058    
1059          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1060              under Win32.
1061          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1062              therefore missing the function definition.
1063          - The compiler thus generates a "C" signature for the test function.
1064          - The linker fails to find the "C" function.
1065          - PCRE fails to configure if asked to do so against libbz2.
1066    
1067    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1068        messages were output:
1069    
1070          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1071          rerunning libtoolize, to keep the correct libtool macros in-tree.
1072          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1073    
1074        I have done both of these things.
1075    
1076    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1077        most of the time, it *can* run out if it is given a pattern that contains a
1078        runaway infinite recursion. I updated the discussion in the pcrestack man
1079        page.
1080    
1081    13. Now that we have gone to the x.xx style of version numbers, the minor
1082        version may start with zero. Using 08 or 09 is a bad idea because users
1083        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1084        interpreted as invalid octal numbers. I've updated the previous comment in
1085        configure.ac, and also added a check that gives an error if 08 or 09 are
1086        used.
1087    
1088    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1089        causing partial matching to fail when the end of the subject matched \W
1090        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1091    
1092    15. There were some discrepancies between the declarations in pcre_internal.h
1093        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1094        their definitions. The declarations used "const uschar *" and the
1095        definitions used USPTR. Even though USPTR is normally defined as "const
1096        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1097        reported that: "This difference in casting confuses some C++ compilers, for
1098        example, SunCC recognizes above declarations as different functions and
1099        generates broken code for hbpcre." I have changed the declarations to use
1100        USPTR.
1101    
1102    16. GNU libtool is named differently on some systems. The autogen.sh script now
1103        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1104        (FreeBSD).
1105    
1106    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1107        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1108        comment: "Figure out how to create a longlong from a string: strtoll and
1109        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1110        instance, but it only takes 2 args instead of 3!"
1111    
1112    18. A subtle bug concerned with back references has been fixed by a change of
1113        specification, with a corresponding code fix. A pattern such as
1114        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1115        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1116        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1117        same bug. Such groups have to be quantified to be useful, or contained
1118        inside another quantified group. (If there's no repetition, the reference
1119        can never match.) The problem arises because, having left the group and
1120        moved on to the rest of the pattern, a later failure that backtracks into
1121        the group uses the captured value from the final iteration of the group
1122        rather than the correct earlier one. I have fixed this in PCRE by forcing
1123        any group that contains a reference to itself to be an atomic group; that
1124        is, there cannot be any backtracking into it once it has completed. This is
1125        similar to recursive and subroutine calls.
1126    
1127    
1128    Version 8.00 19-Oct-09
1129  ----------------------  ----------------------
1130    
1131  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
1132      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
1133      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
1134      error.      error.
1135    
1136  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1137      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1138      in a Windows environment.      in a Windows environment.
1139    
1140  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
1141      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
1142      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
1143      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
1144      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
1145      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
1146      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
1147    
1148  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
1149      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
1150      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
1151      the old behaviour.      the old behaviour.
1152    
1153  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
1154      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
1155      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
1156      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
1157    
1158  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
1159      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1160    
1161  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1162      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
1163      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
1164      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
1165      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
1166      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
1167    
1168  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1169      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
1170      repetition. Chaos could result.      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1171        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1172        character. Chaos in the form of incorrect output or a compiling loop could
1173        result.
1174    
1175  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
1176      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
1177      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
1178      slots in the offset vector, the offsets of the first-encountered partial      slots in the offset vector, the offset of the earliest inspected character
1179      match are set in them when PCRE_ERROR_PARTIAL is returned.      for the match and the offset of the end of the subject are set in them when
1180        PCRE_ERROR_PARTIAL is returned.
1181    
1182  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1183      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
1184      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1185      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
1186      pcre_exec().  
1187    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1188  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
1189      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
1190      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1191      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
1192      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
1193      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
1194      final character ended with (*FAIL).  
   
1195  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1196      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
1197      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
1198      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
1199      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
1200      "sbody" failed.      "sbody" failed. This bug has been fixed.
1201    
1202    13. The string returned by pcre_dfa_exec() after a partial match has been
1203        changed so that it starts at the first inspected character rather than the
1204        first character of the match. This makes a difference only if the pattern
1205        starts with a lookbehind assertion or \b or \B (\K is not supported by
1206        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1207        matching functions compatible, and I think it's the right thing to do.
1208    
1209    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1210        so that the demonstration program is easily available in environments where
1211        PCRE has not been installed from source.
1212    
1213    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1214        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1215        library.
1216    
1217    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1218        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1219        is not the first non-POSIX option to be added. Clearly some people find
1220        these options useful.
1221    
1222    17. If a caller to the POSIX matching function regexec() passes a non-zero
1223        value for nmatch with a NULL value for pmatch, the value of
1224        nmatch is forced to zero.
1225    
1226    18. RunGrepTest did not have a test for the availability of the -u option of
1227        the diff command, as RunTest does. It now checks in the same way as
1228        RunTest, and also checks for the -b option.
1229    
1230    19. If an odd number of negated classes containing just a single character
1231        interposed, within parentheses, between a forward reference to a named
1232        subpattern and the definition of the subpattern, compilation crashed with
1233        an internal error, complaining that it could not find the referenced
1234        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1235        [The bug was that it was starting one character too far in when skipping
1236        over the character class, thus treating the ] as data rather than
1237        terminating the class. This meant it could skip too much.]
1238    
1239    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1240        /g option in pcretest when the pattern contains \K, which makes it possible
1241        to have an empty string match not at the start, even when the pattern is
1242        anchored. Updated pcretest and pcredemo to use this option.
1243    
1244    21. If the maximum number of capturing subpatterns in a recursion was greater
1245        than the maximum at the outer level, the higher number was returned, but
1246        with unset values at the outer level. The correct (outer level) value is
1247        now given.
1248    
1249    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1250        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1251        make it do so. The string so far is captured, making this feature
1252        compatible with Perl.
1253    
1254    23. The tests have been re-organized, adding tests 11 and 12, to make it
1255        possible to check the Perl 5.10 features against Perl 5.10.
1256    
1257    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1258        pattern matches a fixed length string. PCRE did not allow this; now it
1259        does. Neither allows recursion.
1260    
1261    25. I finally figured out how to implement a request to provide the minimum
1262        length of subject string that was needed in order to match a given pattern.
1263        (It was back references and recursion that I had previously got hung up
1264        on.) This code has now been added to pcre_study(); it finds a lower bound
1265        to the length of subject needed. It is not necessarily the greatest lower
1266        bound, but using it to avoid searching strings that are too short does give
1267        some useful speed-ups. The value is available to calling programs via
1268        pcre_fullinfo().
1269    
1270    26. While implementing 25, I discovered to my embarrassment that pcretest had
1271        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1272        study optimizations had never been tested with that matching function.
1273        Oops. What is worse, even when it was passed study data, there was a bug in
1274        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1275        were also very few tests of studied patterns with pcre_dfa_exec().
1276    
1277    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1278        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1279        on the other side of the coin, they are no longer allowed to have different
1280        names, because these cannot be distinguished in PCRE, and this has caused
1281        confusion. (This is a difference from Perl.)
1282    
1283    28. When duplicate subpattern names are present (necessarily with different
1284        numbers, as required by 27 above), and a test is made by name in a
1285        conditional pattern, either for a subpattern having been matched, or for
1286        recursion in such a pattern, all the associated numbered subpatterns are
1287        tested, and the overall condition is true if the condition is true for any
1288        one of them. This is the way Perl works, and is also more like the way
1289        testing by number works.
1290    
1291    
1292  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1293  ---------------------  ---------------------

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