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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.31 06-July-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    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
136        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
137        codepoints that are too big for the mode are faulted, and in a UTF mode,
138        disallowed codepoints are also faulted.
139    
140    39. If PCRE was compiled with UTF support, in three places in the DFA
141        matcher there was code that should only have been obeyed in UTF mode, but
142        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
143        processing when bytes with values greater than 127 were present. In 16-bit
144        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
145        both cases the values are those that cannot be the first data item in a UTF
146        character. The three items that might have provoked this were recursions,
147        possessively repeated groups, and atomic groups.
148    
149    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
150        and pcregrep, because some OS require shared objects to be explicitly
151        passed to ld, causing the link step to fail if they are not.
152    
153    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
154        mode, patterns that started with \h* or \R* might be incorrectly matched.
155    
156    
157    Version 8.30 04-February-2012
158    -----------------------------
159    
160    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
161        name is defined in ctype.h.
162    
163    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
164        only in quite long subpatterns.
165    
166    3.  Removed the function pcre_info(), which has been obsolete and deprecated
167        since it was replaced by pcre_fullinfo() in February 2000.
168    
169    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
170        match a (*MARK), and the match failed at the start of the subject, a
171        reference to memory before the start of the subject could occur. This bug
172        was introduced by fix 17 of release 8.21.
173    
174    5.  A reference to an unset group with zero minimum repetition was giving
175        totally wrong answers (in non-JavaScript-compatibility mode). For example,
176        /(another)?(\1?)test/ matched against "hello world test". This bug was
177        introduced in release 8.13.
178    
179    6.  Add support for 16-bit character strings (a large amount of work involving
180        many changes and refactorings).
181    
182    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
183        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
184        from a file.
185    
186    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
187        rounding is not applied in this particular case).
188    
189    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
190        if they appear, or are escaped, in patterns.
191    
192    10. Get rid of a number of -Wunused-but-set-variable warnings.
193    
194    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
195        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
196        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
197        also returns the mark "x". This bug applied to capturing parentheses,
198        non-capturing parentheses, and atomic parentheses. It also applied to some
199        assertions.
200    
201    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
202        information out of configure.ac instead of relying on pcre.h.generic, which
203        is not stored in the repository.
204    
205    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
206        -lreadline.
207    
208    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
209    
210    15. Applied Graycode's patch to put the top-level frame on the stack rather
211        than the heap when not using the stack for recursion. This gives a
212        performance improvement in many cases when recursion is not deep.
213    
214    16. Experimental code added to "pcretest -C" to output the stack frame size.
215    
216    
217    Version 8.21 12-Dec-2011
218    ------------------------
219    
220    1.  Updating the JIT compiler.
221    
222    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
223        are added as well.
224    
225    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
226        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
227        calling _pcre_jit_exec. Some extra comments are added.
228    
229    4.  (*MARK) settings inside atomic groups that do not contain any capturing
230        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
231        was introduced by change 18 for 8.20.
232    
233    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
234        ECMA-262 standard.
235    
236    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
237        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
238        This bug was probably introduced by change 9 of 8.13.
239    
240    7.  While fixing 6 above, I noticed that a number of other items were being
241        incorrectly rejected as "not fixed length". This arose partly because newer
242        opcodes had not been added to the fixed-length checking code. I have (a)
243        corrected the bug and added tests for these items, and (b) arranged for an
244        error to occur if an unknown opcode is encountered while checking for fixed
245        length instead of just assuming "not fixed length". The items that were
246        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
247        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
248        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
249    
250    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
251        being incorrectly compiled and would have given unpredicatble results.
252    
253    9.  A possessively repeated subpattern with minimum repeat count greater than
254        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
255        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
256        the first (A) could occur when it should not.
257    
258    10. Add a cast and remove a redundant test from the code.
259    
260    11. JIT should use pcre_malloc/pcre_free for allocation.
261    
262    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
263        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
264        is anything other than /usr, -L is still shown).
265    
266    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
267    
268    14. Perl does not support \N without a following name in a [] class; PCRE now
269        also gives an error.
270    
271    15. If a forward reference was repeated with an upper limit of around 2000,
272        it caused the error "internal error: overran compiling workspace". The
273        maximum number of forward references (including repeats) was limited by the
274        internal workspace, and dependent on the LINK_SIZE. The code has been
275        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
276        the default depends on LINK_SIZE. There is a new upper limit (for safety)
277        of around 200,000 forward references. While doing this, I also speeded up
278        the filling in of repeated forward references.
279    
280    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
281        incorrectly expecting the subject to contain another "a" after the start.
282    
283    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
284        in the match, the SKIP should be ignored. This was not happening; instead
285        the SKIP was being treated as NOMATCH. For patterns such as
286        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
287        tested.
288    
289    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
290        now much more compatible with Perl, in particular in cases where the result
291        is a non-match for a non-anchored pattern. For example, if
292        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
293        "m", where previously it did not return a name. A side effect of this
294        change is that for partial matches, the last encountered mark name is
295        returned, as for non matches. A number of tests that were previously not
296        Perl-compatible have been moved into the Perl-compatible test files. The
297        refactoring has had the pleasing side effect of removing one argument from
298        the match() function, thus reducing its stack requirements.
299    
300    19. If the /S+ option was used in pcretest to study a pattern using JIT,
301        subsequent uses of /S (without +) incorrectly behaved like /S+.
302    
303    21. Retrieve executable code size support for the JIT compiler and fixing
304        some warnings.
305    
306    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
307        not work when the shorter character appeared right at the end of the
308        subject string.
309    
310    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
311        systems.
312    
313    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
314        output it when the /M option is used in pcretest.
315    
316    25. The CheckMan script was not being included in the distribution. Also, added
317        an explicit "perl" to run Perl scripts from the PrepareRelease script
318        because this is reportedly needed in Windows.
319    
320    26. If study data was being save in a file and studying had not found a set of
321        "starts with" bytes for the pattern, the data written to the file (though
322        never used) was taken from uninitialized memory and so caused valgrind to
323        complain.
324    
325    27. Updated RunTest.bat as provided by Sheri Pierce.
326    
327    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
328    
329    29. Computation of memory usage for the table of capturing group names was
330        giving an unnecessarily large value.
331    
332    
333    Version 8.20 21-Oct-2011
334    ------------------------
335    
336    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
337        a POSIX class. After further experiments with Perl, which convinced me that
338        Perl has bugs and confusions, a closing square bracket is no longer allowed
339        in a POSIX name. This bug also affected patterns with classes that started
340        with full stops.
341    
342    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
343        captured substring, but while checking the failing first alternative,
344        substring 1 is temporarily captured. If the output vector supplied to
345        pcre_exec() was not big enough for this capture, the yield of the function
346        was still zero ("insufficient space for captured substrings"). This cannot
347        be totally fixed without adding another stack variable, which seems a lot
348        of expense for a edge case. However, I have improved the situation in cases
349        such as /(a)(b)x|abc/ matched against "abc", where the return code
350        indicates that fewer than the maximum number of slots in the ovector have
351        been set.
352    
353    3.  Related to (2) above: when there are more back references in a pattern than
354        slots in the output vector, pcre_exec() uses temporary memory during
355        matching, and copies in the captures as far as possible afterwards. It was
356        using the entire output vector, but this conflicts with the specification
357        that only 2/3 is used for passing back captured substrings. Now it uses
358        only the first 2/3, for compatibility. This is, of course, another edge
359        case.
360    
361    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
362        main code base, and can be used by building with --enable-jit. When this is
363        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
364        runtime --no-jit option is given.
365    
366    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
367        ovector, the return from the function was zero, implying that there were
368        other matches that did not fit. The correct "exactly full" value is now
369        returned.
370    
371    6.  If a subpattern that was called recursively or as a subroutine contained
372        (*PRUNE) or any other control that caused it to give a non-standard return,
373        invalid errors such as "Error -26 (nested recursion at the same subject
374        position)" or even infinite loops could occur.
375    
376    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
377        computing the minimum length on reaching *ACCEPT, and so ended up with the
378        wrong value of 1 rather than 0. Further investigation indicates that
379        computing a minimum subject length in the presence of *ACCEPT is difficult
380        (think back references, subroutine calls), and so I have changed the code
381        so that no minimum is registered for a pattern that contains *ACCEPT.
382    
383    8.  If (*THEN) was present in the first (true) branch of a conditional group,
384        it was not handled as intended. [But see 16 below.]
385    
386    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
387        Sheri Pierce.
388    
389    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
390        the first byte in a match must be "a".
391    
392    11. Change 17 for 8.13 increased the recursion depth for patterns like
393        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
394        pattern contains any instances of (*THEN). If it does not, the old
395        optimizations are restored. It would be nice to do this on a per-group
396        basis, but at the moment that is not feasible.
397    
398    12. In some environments, the output of pcretest -C is CRLF terminated. This
399        broke RunTest's code that checks for the link size. A single white space
400        character after the value is now allowed for.
401    
402    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
403        For "fr", it uses the Windows-specific input and output files.
404    
405    14. If (*THEN) appeared in a group that was called recursively or as a
406        subroutine, it did not work as intended. [But see next item.]
407    
408    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
409        pattern fragments (but not containing any | characters). If A and B are
410        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
411        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
412        D. In other words, Perl considers parentheses that do not contain any |
413        characters to be part of a surrounding alternative, whereas PCRE was
414        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
415        differently. PCRE now behaves in the same way as Perl, except in the case
416        of subroutine/recursion calls such as (?1) which have in any case always
417        been different (but PCRE had them first :-).
418    
419    16. Related to 15 above: Perl does not treat the | in a conditional group as
420        creating alternatives. Such a group is treated in the same way as an
421        ordinary group without any | characters when processing (*THEN). PCRE has
422        been changed to match Perl's behaviour.
423    
424    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
425        RunGrepTest script failed.
426    
427    18. Change 22 for version 13 caused atomic groups to use more stack. This is
428        inevitable for groups that contain captures, but it can lead to a lot of
429        stack use in large patterns. The old behaviour has been restored for atomic
430        groups that do not contain any capturing parentheses.
431    
432    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
433        suppress the check for a minimum subject length at run time. (If it was
434        given to pcre_exec() or pcre_dfa_exec() it did work.)
435    
436    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
437        fail to work when decoding hex characters in data strings in EBCDIC
438        environments.
439    
440    21. It appears that in at least one Mac OS environment, the isxdigit() function
441        is implemented as a macro that evaluates to its argument more than once,
442        contravening the C 90 Standard (I haven't checked a later standard). There
443        was an instance in pcretest which caused it to go wrong when processing
444        \x{...} escapes in subject strings. The has been rewritten to avoid using
445        things like p++ in the argument of isxdigit().
446    
447    
448    Version 8.13 16-Aug-2011
449    ------------------------
450    
451    1.  The Unicode data tables have been updated to Unicode 6.0.0.
452    
453    2.  Two minor typos in pcre_internal.h have been fixed.
454    
455    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
456        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
457        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
458    
459    4.  There were a number of related bugs in the code for matching backrefences
460        caselessly in UTF-8 mode when codes for the characters concerned were
461        different numbers of bytes. For example, U+023A and U+2C65 are an upper
462        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
463        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
464        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
465        2-byte code at the end of the subject (it thought there wasn't enough data
466        left).
467    
468    5.  Comprehensive information about what went wrong is now returned by
469        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
470        as the output vector has at least 2 elements. The offset of the start of
471        the failing character and a reason code are placed in the vector.
472    
473    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
474        now returned is for the first byte of the failing character, instead of the
475        last byte inspected. This is an incompatible change, but I hope it is small
476        enough not to be a problem. It makes the returned offset consistent with
477        pcre_exec() and pcre_dfa_exec().
478    
479    7.  pcretest now gives a text phrase as well as the error number when
480        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
481        failure, the offset and reason code are output.
482    
483    8.  When \R was used with a maximizing quantifier it failed to skip backwards
484        over a \r\n pair if the subsequent match failed. Instead, it just skipped
485        back over a single character (\n). This seems wrong (because it treated the
486        two characters as a single entity when going forwards), conflicts with the
487        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
488        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
489        has been changed.
490    
491    9.  Some internal refactoring has changed the processing so that the handling
492        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
493        time (the PCRE_DOTALL option was changed this way some time ago: version
494        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
495        which was always a bit of a fudge. It also means that there is one less
496        argument for the match() function, which reduces its stack requirements
497        slightly. This change also fixes an incompatibility with Perl: the pattern
498        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
499    
500    10. More internal refactoring has drastically reduced the number of recursive
501        calls to match() for possessively repeated groups such as (abc)++ when
502        using pcre_exec().
503    
504    11. While implementing 10, a number of bugs in the handling of groups were
505        discovered and fixed:
506    
507        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
508        (a|)*(?1) gave a compile-time internal error.
509        ((a|)+)+  did not notice that the outer group could match an empty string.
510        (^a|^)+   was not marked as anchored.
511        (.*a|.*)+ was not marked as matching at start or after a newline.
512    
513    12. Yet more internal refactoring has removed another argument from the match()
514        function. Special calls to this function are now indicated by setting a
515        value in a variable in the "match data" data block.
516    
517    13. Be more explicit in pcre_study() instead of relying on "default" for
518        opcodes that mean there is no starting character; this means that when new
519        ones are added and accidentally left out of pcre_study(), testing should
520        pick them up.
521    
522    14. The -s option of pcretest has been documented for ages as being an old
523        synonym of -m (show memory usage). I have changed it to mean "force study
524        for every regex", that is, assume /S for every regex. This is similar to -i
525        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
526        using it. It makes it easier to run collections of tests with and without
527        study enabled, and thereby test pcre_study() more easily. All the standard
528        tests are now run with and without -s (but some patterns can be marked as
529        "never study" - see 20 below).
530    
531    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
532        restoration of the capturing data to the outer values was not happening
533        correctly.
534    
535    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
536        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
537        pattern had matched an empty string, and so incorrectly returned a no
538        match.
539    
540    17. There was optimizing code for the last branch of non-capturing parentheses,
541        and also for the obeyed branch of a conditional subexpression, which used
542        tail recursion to cut down on stack usage. Unfortunately, now that there is
543        the possibility of (*THEN) occurring in these branches, tail recursion is
544        no longer possible because the return has to be checked for (*THEN). These
545        two optimizations have therefore been removed. [But see 8.20/11 above.]
546    
547    18. If a pattern containing \R was studied, it was assumed that \R always
548        matched two bytes, thus causing the minimum subject length to be
549        incorrectly computed because \R can also match just one byte.
550    
551    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
552        was incorrectly computed.
553    
554    20. If /S is present twice on a test pattern in pcretest input, it now
555        *disables* studying, thereby overriding the use of -s on the command line
556        (see 14 above). This is necessary for one or two tests to keep the output
557        identical in both cases.
558    
559    21. When (*ACCEPT) was used in an assertion that matched an empty string and
560        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
561    
562    22. When an atomic group that contained a capturing parenthesis was
563        successfully matched, but the branch in which it appeared failed, the
564        capturing was not being forgotten if a higher numbered group was later
565        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
566        group 1 to "a", when in fact it should be unset. This applied to multi-
567        branched capturing and non-capturing groups, repeated or not, and also to
568        positive assertions (capturing in negative assertions does not happen
569        in PCRE) and also to nested atomic groups.
570    
571    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
572        subject after a captured substring, to make it easier to tell which of a
573        number of identical substrings has been captured.
574    
575    24. The way atomic groups are processed by pcre_exec() has been changed so that
576        if they are repeated, backtracking one repetition now resets captured
577        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
578        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
579        "aaa". Previously, it would have been "a". As part of this code
580        refactoring, the way recursive calls are handled has also been changed.
581    
582    25. If an assertion condition captured any substrings, they were not passed
583        back unless some other capturing happened later. For example, if
584        (?(?=(a))a) was matched against "a", no capturing was returned.
585    
586    26. When studying a pattern that contained subroutine calls or assertions,
587        the code for finding the minimum length of a possible match was handling
588        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
589        group 1 called group 2 while simultaneously a separate group 2 called group
590        1). A stack overflow occurred in this case. I have fixed this by limiting
591        the recursion depth to 10.
592    
593    27. Updated RunTest.bat in the distribution to the version supplied by Tom
594        Fortmann. This supports explicit test numbers on the command line, and has
595        argument validation and error reporting.
596    
597    28. An instance of \X with an unlimited repeat could fail if at any point the
598        first character it looked at was a mark character.
599    
600    29. Some minor code refactoring concerning Unicode properties and scripts
601        should reduce the stack requirement of match() slightly.
602    
603    30. Added the '=' option to pcretest to check the setting of unused capturing
604        slots at the end of the pattern, which are documented as being -1, but are
605        not included in the return count.
606    
607    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
608        compiled something random. Now it gives a compile-time error (as does
609        Perl).
610    
611    32. A *MARK encountered during the processing of a positive assertion is now
612        recorded and passed back (compatible with Perl).
613    
614    33. If --only-matching or --colour was set on a pcregrep call whose pattern
615        had alternative anchored branches, the search for a second match in a line
616        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
617        matched the line "0102" twice. The same bug affected patterns that started
618        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
619        twice.
620    
621    34. Previously, PCRE did not allow quantification of assertions. However, Perl
622        does, and because of capturing effects, quantifying parenthesized
623        assertions may at times be useful. Quantifiers are now allowed for
624        parenthesized assertions.
625    
626    35. A minor code tidy in pcre_compile() when checking options for \R usage.
627    
628    36. \g was being checked for fancy things in a character class, when it should
629        just be a literal "g".
630    
631    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
632        appearance of a nested POSIX class supersedes an apparent external class.
633        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
634        unescaped square brackets may also appear as part of class names. For
635        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
636        more like Perl. (But see 8.20/1 above.)
637    
638    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
639        was because it thought it was \N{name}, which is not supported).
640    
641    39. Add minix to OS list not supporting the -S option in pcretest.
642    
643    40. PCRE tries to detect cases of infinite recursion at compile time, but it
644        cannot analyze patterns in sufficient detail to catch mutual recursions
645        such as ((?1))((?2)). There is now a runtime test that gives an error if a
646        subgroup is called recursively as a subpattern for a second time at the
647        same position in the subject string. In previous releases this might have
648        been caught by the recursion limit, or it might have run out of stack.
649    
650    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
651        happen only once. PCRE was, however incorrectly giving a compile time error
652        "recursive call could loop indefinitely" because it cannot analyze the
653        pattern in sufficient detail. The compile time test no longer happens when
654        PCRE is compiling a conditional subpattern, but actual runaway loops are
655        now caught at runtime (see 40 above).
656    
657    42. It seems that Perl allows any characters other than a closing parenthesis
658        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
659        has been changed to be the same.
660    
661    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
662        as not to get warnings when autogen.sh is called. Also changed
663        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
664    
665    44. To help people who use pcregrep to scan files containing exceedingly long
666        lines, the following changes have been made:
667    
668        (a) The default value of the buffer size parameter has been increased from
669            8K to 20K. (The actual buffer used is three times this size.)
670    
671        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
672            PCRE is built.
673    
674        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
675            to be set at run time.
676    
677        (d) Numerical values in pcregrep options can be followed by K or M, for
678            example --buffer-size=50K.
679    
680        (e) If a line being scanned overflows pcregrep's buffer, an error is now
681            given and the return code is set to 2.
682    
683    45. Add a pointer to the latest mark to the callout data block.
684    
685    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
686        partial match of an empty string instead of no match. This was specific to
687        the use of ".".
688    
689    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
690        complete match instead of a partial match. This bug was dependent on both
691        the PCRE_UTF8 and PCRE_DOTALL options being set.
692    
693    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
694        starting byte set, because \b was not being ignored.
695    
696    
697    Version 8.12 15-Jan-2011
698    ------------------------
699    
700    1.  Fixed some typos in the markup of the man pages, and wrote a script that
701        checks for such things as part of the documentation building process.
702    
703    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
704        --match-limit and --recursion-limit options (added for 8.11). In
705        particular, this made one of the standard tests fail. (The integer value
706        went into the wrong half of a long int.)
707    
708    3.  If the --colour option was given to pcregrep with -v (invert match), it
709        did strange things, either producing crazy output, or crashing. It should,
710        of course, ignore a request for colour when reporting lines that do not
711        match.
712    
713    4.  Another pcregrep bug caused similar problems if --colour was specified with
714        -M (multiline) and the pattern match finished with a line ending.
715    
716    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
717        matched in multiline mode, the following line was shown as part of the
718        match. This seems wrong, so I have changed it.
719    
720    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
721        the check for further matches in the same line (so they could be coloured)
722        to overrun the end of the current line. If another match was found, it was
723        incorrectly shown (and then shown again when found in the next line).
724    
725    7.  If pcregrep was compiled under Windows, there was a reference to the
726        function pcregrep_exit() before it was defined. I am assuming this was
727        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
728        reported by a user. I've moved the definition above the reference.
729    
730    
731    Version 8.11 10-Dec-2010
732    ------------------------
733    
734    1.  (*THEN) was not working properly if there were untried alternatives prior
735        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
736        backtracked to try for "b" instead of moving to the next alternative branch
737        at the same level (in this case, to look for "c"). The Perl documentation
738        is clear that when (*THEN) is backtracked onto, it goes to the "next
739        alternative in the innermost enclosing group".
740    
741    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
742        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
743        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
744        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
745        (*THEN).
746    
747    3.  If \s appeared in a character class, it removed the VT character from
748        the class, even if it had been included by some previous item, for example
749        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
750        of \s, but is part of the POSIX "space" class.)
751    
752    4.  A partial match never returns an empty string (because you can always
753        match an empty string at the end of the subject); however the checking for
754        an empty string was starting at the "start of match" point. This has been
755        changed to the "earliest inspected character" point, because the returned
756        data for a partial match starts at this character. This means that, for
757        example, /(?<=abc)def/ gives a partial match for the subject "abc"
758        (previously it gave "no match").
759    
760    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
761        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
762        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
763        has an implication that the given string is incomplete (because a partial
764        match is preferred over a full match). For this reason, these items now
765        give a partial match in this situation. [Aside: previously, the one case
766        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
767        match rather than a full match, which was wrong by the old rules, but is
768        now correct.]
769    
770    6.  There was a bug in the handling of #-introduced comments, recognized when
771        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
772        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
773        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
774        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
775        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
776        places in pcre_compile().
777    
778    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
779        comments when looking ahead for named forward references to subpatterns,
780        the only newline sequence it recognized was NL. It now handles newlines
781        according to the set newline convention.
782    
783    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
784        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
785        cater for a lack of strerror(). These oversights have been fixed.
786    
787    9.  Added --match-limit and --recursion-limit to pcregrep.
788    
789    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
790    
791    11. When the -o option was used, pcregrep was setting a return code of 1, even
792        when matches were found, and --line-buffered was not being honoured.
793    
794    12. Added an optional parentheses number to the -o and --only-matching options
795        of pcregrep.
796    
797    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
798        can match an empty string. The code to do it in pcretest and pcredemo
799        needed fixing:
800    
801        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
802            only one byte after an empty string match just before CRLF (this case
803            just got forgotten; "any" and "anycrlf" were OK).
804    
805        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
806            mode when an empty string match preceded an ASCII character followed by
807            a non-ASCII character. (The code for advancing by one character rather
808            than one byte was nonsense.)
809    
810        (c) The pcredemo.c sample program did not have any code at all to handle
811            the cases when CRLF is a valid newline sequence.
812    
813    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
814        as a starting offset was within the subject string. There is now a new
815        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
816        negative or greater than the length of the string. In order to test this,
817        pcretest is extended to allow the setting of negative starting offsets.
818    
819    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
820        starting offset points to the beginning of a UTF-8 character was
821        unnecessarily clumsy. I tidied it up.
822    
823    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
824        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
825    
826    17. Nobody had reported that the --include_dir option, which was added in
827        release 7.7 should have been called --include-dir (hyphen, not underscore)
828        for compatibility with GNU grep. I have changed it to --include-dir, but
829        left --include_dir as an undocumented synonym, and the same for
830        --exclude-dir, though that is not available in GNU grep, at least as of
831        release 2.5.4.
832    
833    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
834        characters from a string of bytes) have been redefined so as not to use
835        loops, in order to improve performance in some environments. At the same
836        time, I abstracted some of the common code into auxiliary macros to save
837        repetition (this should not affect the compiled code).
838    
839    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
840        compile-time error is now given if \c is not followed by an ASCII
841        character, that is, a byte less than 128. (In EBCDIC mode, the code is
842        different, and any byte value is allowed.)
843    
844    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
845        START_OPTIMIZE option, which is now allowed at compile time - but just
846        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
847        to pcregrep and other applications that have no direct access to PCRE
848        options. The new /Y option in pcretest sets this option when calling
849        pcre_compile().
850    
851    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
852        back references. Groups containing recursive back references were forced to
853        be atomic by that change, but in the case of named groups, the amount of
854        memory required was incorrectly computed, leading to "Failed: internal
855        error: code overflow". This has been fixed.
856    
857    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
858        pcretest.c, to avoid build problems in some Borland environments.
859    
860    
861    Version 8.10 25-Jun-2010
862    ------------------------
863    
864    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
865        THEN.
866    
867    2.  (*ACCEPT) was not working when inside an atomic group.
868    
869    3.  Inside a character class, \B is treated as a literal by default, but
870        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
871        causes the error). The code is unchanged, but I tidied the documentation.
872    
873    4.  Inside a character class, PCRE always treated \R and \X as literals,
874        whereas Perl faults them if its -w option is set. I have changed PCRE so
875        that it faults them when PCRE_EXTRA is set.
876    
877    5.  Added support for \N, which always matches any character other than
878        newline. (It is the same as "." when PCRE_DOTALL is not set.)
879    
880    6.  When compiling pcregrep with newer versions of gcc which may have
881        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
882        declared with attribute warn_unused_result" were given. Just casting the
883        result to (void) does not stop the warnings; a more elaborate fudge is
884        needed. I've used a macro to implement this.
885    
886    7.  Minor change to pcretest.c to avoid a compiler warning.
887    
888    8.  Added four artifical Unicode properties to help with an option to make
889        \s etc use properties (see next item). The new properties are: Xan
890        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
891    
892    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
893        use Unicode properties. (*UCP) at the start of a pattern can be used to set
894        this option. Modified pcretest to add /W to test this facility. Added
895        REG_UCP to make it available via the POSIX interface.
896    
897    10. Added --line-buffered to pcregrep.
898    
899    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
900        studied, and the match started with a letter with a code point greater than
901        127 whose first byte was different to the first byte of the other case of
902        the letter, the other case of this starting letter was not recognized
903        (#976).
904    
905    12. If a pattern that was studied started with a repeated Unicode property
906        test, for example, \p{Nd}+, there was the theoretical possibility of
907        setting up an incorrect bitmap of starting bytes, but fortunately it could
908        not have actually happened in practice until change 8 above was made (it
909        added property types that matched character-matching opcodes).
910    
911    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
912        possible starting bytes for non-anchored patterns.
913    
914    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
915        \R, and also a number of cases that involve Unicode properties, both
916        explicit and implicit when PCRE_UCP is set.
917    
918    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
919        input, it could crash or give wrong results if characters with values
920        greater than 0xc0 were present in the subject string. (Detail: it assumed
921        UTF-8 input when processing these items.)
922    
923    16. Added a lot of (int) casts to avoid compiler warnings in systems where
924        size_t is 64-bit (#991).
925    
926    17. Added a check for running out of memory when PCRE is compiled with
927        --disable-stack-for-recursion (#990).
928    
929    18. If the last data line in a file for pcretest does not have a newline on
930        the end, a newline was missing in the output.
931    
932    19. The default pcre_chartables.c file recognizes only ASCII characters (values
933        less than 128) in its various bitmaps. However, there is a facility for
934        generating tables according to the current locale when PCRE is compiled. It
935        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
936        characters, are recognized by isspace() and therefore were getting set in
937        these tables, and indeed these tables seem to approximate to ISO 8859. This
938        caused a problem in UTF-8 mode when pcre_study() was used to create a list
939        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
940        which of course cannot start UTF-8 characters. I have changed the code so
941        that only real ASCII characters (less than 128) and the correct starting
942        bytes for UTF-8 encodings are set for characters greater than 127 when in
943        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
944        altogether.)
945    
946    20. Added the /T option to pcretest so as to be able to run tests with non-
947        standard character tables, thus making it possible to include the tests
948        used for 19 above in the standard set of tests.
949    
950    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
951        reference to a subpattern the other side of a comment that contains an
952        opening parenthesis caused either an internal compiling error, or a
953        reference to the wrong subpattern.
954    
955    
956    Version 8.02 19-Mar-2010
957    ------------------------
958    
959    1.  The Unicode data tables have been updated to Unicode 5.2.0.
960    
961    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
962        configured.
963    
964    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
965        original author of that file, following a query about its status.
966    
967    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
968        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
969    
970    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
971        quantifier applied to a forward-referencing subroutine call, could compile
972        incorrect code or give the error "internal error: previously-checked
973        referenced subpattern not found".
974    
975    6.  Both MS Visual Studio and Symbian OS have problems with initializing
976        variables to point to external functions. For these systems, therefore,
977        pcre_malloc etc. are now initialized to local functions that call the
978        relevant global functions.
979    
980    7.  There were two entries missing in the vectors called coptable and poptable
981        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
982        I've fixed the data, and added a kludgy way of testing at compile time that
983        the lengths are correct (equal to the number of opcodes).
984    
985    8.  Following on from 7, I added a similar kludge to check the length of the
986        eint vector in pcreposix.c.
987    
988    9.  Error texts for pcre_compile() are held as one long string to avoid too
989        much relocation at load time. To find a text, the string is searched,
990        counting zeros. There was no check for running off the end of the string,
991        which could happen if a new error number was added without updating the
992        string.
993    
994    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
995    
996    11. \K was not working if it appeared in an atomic group or in a group that
997        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
998        \K is "not well defined" if used in an assertion. PCRE now accepts it if
999        the assertion is positive, but not if it is negative.
1000    
1001    12. Change 11 fortuitously reduced the size of the stack frame used in the
1002        "match()" function of pcre_exec.c by one pointer. Forthcoming
1003        implementation of support for (*MARK) will need an extra pointer on the
1004        stack; I have reserved it now, so that the stack frame size does not
1005        decrease.
1006    
1007    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1008        item in branch that calls a recursion is a subroutine call - as in the
1009        second branch in the above example - was incorrectly given the compile-
1010        time error "recursive call could loop indefinitely" because pcre_compile()
1011        was not correctly checking the subroutine for matching a non-empty string.
1012    
1013    14. The checks for overrunning compiling workspace could trigger after an
1014        overrun had occurred. This is a "should never occur" error, but it can be
1015        triggered by pathological patterns such as hundreds of nested parentheses.
1016        The checks now trigger 100 bytes before the end of the workspace.
1017    
1018    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1019    
1020    
1021    Version 8.01 19-Jan-2010
1022    ------------------------
1023    
1024    1.  If a pattern contained a conditional subpattern with only one branch (in
1025        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1026        computed the wrong minimum data length (which is of course zero for such
1027        subpatterns). This could cause incorrect "no match" results.
1028    
1029    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1030        the pattern is reset in the first branch, pcre_compile() failed with
1031        "internal error: code overflow at offset...". This happened only when
1032        the reset was to the original external option setting. (An optimization
1033        abstracts leading options settings into an external setting, which was the
1034        cause of this.)
1035    
1036    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1037        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1038        assertion pattern did not match (meaning that the assertion was true), it
1039        was incorrectly treated as false if the SKIP had been reached during the
1040        matching. This also applied to assertions used as conditions.
1041    
1042    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1043        assertion subpattern, including such a pattern used as a condition,
1044        unpredictable results occurred, instead of the error return
1045        PCRE_ERROR_DFA_UITEM.
1046    
1047    5.  The C++ GlobalReplace function was not working like Perl for the special
1048        situation when an empty string is matched. It now does the fancy magic
1049        stuff that is necessary.
1050    
1051    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1052        removed. (These were left over from very, very early versions of PCRE.)
1053    
1054    7.  Some cosmetic changes to the code to make life easier when compiling it
1055        as part of something else:
1056    
1057        (a) Change DEBUG to PCRE_DEBUG.
1058    
1059        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1060            called "current" as "current_branch", to prevent a collision with the
1061            Linux macro when compiled as a kernel module.
1062    
1063        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1064            prevent a collision with the Linux macro when compiled as a kernel
1065            module.
1066    
1067    8.  In pcre_compile() there are some checks for integer overflows that used to
1068        cast potentially large values to (double). This has been changed to that
1069        when building, a check for int64_t is made, and if it is found, it is used
1070        instead, thus avoiding the use of floating point arithmetic. (There is no
1071        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1072        double.
1073    
1074    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1075        2005 (difference between two addresses compared to an unsigned value).
1076    
1077    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1078        custom one, because of the following reported problem in Windows:
1079    
1080          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1081              under Win32.
1082          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1083              therefore missing the function definition.
1084          - The compiler thus generates a "C" signature for the test function.
1085          - The linker fails to find the "C" function.
1086          - PCRE fails to configure if asked to do so against libbz2.
1087    
1088    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1089        messages were output:
1090    
1091          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1092          rerunning libtoolize, to keep the correct libtool macros in-tree.
1093          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1094    
1095        I have done both of these things.
1096    
1097    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1098        most of the time, it *can* run out if it is given a pattern that contains a
1099        runaway infinite recursion. I updated the discussion in the pcrestack man
1100        page.
1101    
1102    13. Now that we have gone to the x.xx style of version numbers, the minor
1103        version may start with zero. Using 08 or 09 is a bad idea because users
1104        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1105        interpreted as invalid octal numbers. I've updated the previous comment in
1106        configure.ac, and also added a check that gives an error if 08 or 09 are
1107        used.
1108    
1109    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1110        causing partial matching to fail when the end of the subject matched \W
1111        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1112    
1113    15. There were some discrepancies between the declarations in pcre_internal.h
1114        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1115        their definitions. The declarations used "const uschar *" and the
1116        definitions used USPTR. Even though USPTR is normally defined as "const
1117        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1118        reported that: "This difference in casting confuses some C++ compilers, for
1119        example, SunCC recognizes above declarations as different functions and
1120        generates broken code for hbpcre." I have changed the declarations to use
1121        USPTR.
1122    
1123    16. GNU libtool is named differently on some systems. The autogen.sh script now
1124        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1125        (FreeBSD).
1126    
1127    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1128        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1129        comment: "Figure out how to create a longlong from a string: strtoll and
1130        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1131        instance, but it only takes 2 args instead of 3!"
1132    
1133    18. A subtle bug concerned with back references has been fixed by a change of
1134        specification, with a corresponding code fix. A pattern such as
1135        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1136        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1137        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1138        same bug. Such groups have to be quantified to be useful, or contained
1139        inside another quantified group. (If there's no repetition, the reference
1140        can never match.) The problem arises because, having left the group and
1141        moved on to the rest of the pattern, a later failure that backtracks into
1142        the group uses the captured value from the final iteration of the group
1143        rather than the correct earlier one. I have fixed this in PCRE by forcing
1144        any group that contains a reference to itself to be an atomic group; that
1145        is, there cannot be any backtracking into it once it has completed. This is
1146        similar to recursive and subroutine calls.
1147    
1148    
1149    Version 8.00 19-Oct-09
1150  ----------------------  ----------------------
1151    
1152  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
1153      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
1154      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
1155      error.      error.
1156    
1157  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,
1158      "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
1159      in a Windows environment.      in a Windows environment.
1160    
1161  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
1162      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
1163      --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
1164      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
1165      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
1166      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
1167      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
1168    
1169  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
1170      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
1171      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
1172      the old behaviour.      the old behaviour.
1173    
1174  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
1175      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
1176      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
1177      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
1178    
1179  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
1180      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1181    
1182  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
1183      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
1184      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
1185      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
1186      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
1187      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
1188    
1189    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1190        was a minimum greater than 1 for a wide character in a possessive
1191        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1192        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1193        character. Chaos in the form of incorrect output or a compiling loop could
1194        result.
1195    
1196    9.  The restrictions on what a pattern can contain when partial matching is
1197        requested for pcre_exec() have been removed. All patterns can now be
1198        partially matched by this function. In addition, if there are at least two
1199        slots in the offset vector, the offset of the earliest inspected character
1200        for the match and the offset of the end of the subject are set in them when
1201        PCRE_ERROR_PARTIAL is returned.
1202    
1203    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1204        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1205        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1206        and may be more useful for multi-segment matching.
1207    
1208    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1209        used to be given if ever the end of the subject was reached; now it is
1210        given only if matching could not proceed because another character was
1211        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1212        string "Z", which now yields "no match" instead of "partial match". In the
1213        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1214        final character ended with (*FAIL).
1215    
1216    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1217        if the pattern had a "must contain" character that was already found in the
1218        earlier partial match, unless partial matching was again requested. For
1219        example, with the pattern /dog.(body)?/, the "must contain" character is
1220        "g". If the first part-match was for the string "dog", restarting with
1221        "sbody" failed. This bug has been fixed.
1222    
1223    13. The string returned by pcre_dfa_exec() after a partial match has been
1224        changed so that it starts at the first inspected character rather than the
1225        first character of the match. This makes a difference only if the pattern
1226        starts with a lookbehind assertion or \b or \B (\K is not supported by
1227        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1228        matching functions compatible, and I think it's the right thing to do.
1229    
1230    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1231        so that the demonstration program is easily available in environments where
1232        PCRE has not been installed from source.
1233    
1234    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1235        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1236        library.
1237    
1238    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1239        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1240        is not the first non-POSIX option to be added. Clearly some people find
1241        these options useful.
1242    
1243    17. If a caller to the POSIX matching function regexec() passes a non-zero
1244        value for nmatch with a NULL value for pmatch, the value of
1245        nmatch is forced to zero.
1246    
1247    18. RunGrepTest did not have a test for the availability of the -u option of
1248        the diff command, as RunTest does. It now checks in the same way as
1249        RunTest, and also checks for the -b option.
1250    
1251    19. If an odd number of negated classes containing just a single character
1252        interposed, within parentheses, between a forward reference to a named
1253        subpattern and the definition of the subpattern, compilation crashed with
1254        an internal error, complaining that it could not find the referenced
1255        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1256        [The bug was that it was starting one character too far in when skipping
1257        over the character class, thus treating the ] as data rather than
1258        terminating the class. This meant it could skip too much.]
1259    
1260    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1261        /g option in pcretest when the pattern contains \K, which makes it possible
1262        to have an empty string match not at the start, even when the pattern is
1263        anchored. Updated pcretest and pcredemo to use this option.
1264    
1265    21. If the maximum number of capturing subpatterns in a recursion was greater
1266        than the maximum at the outer level, the higher number was returned, but
1267        with unset values at the outer level. The correct (outer level) value is
1268        now given.
1269    
1270    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1271        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1272        make it do so. The string so far is captured, making this feature
1273        compatible with Perl.
1274    
1275    23. The tests have been re-organized, adding tests 11 and 12, to make it
1276        possible to check the Perl 5.10 features against Perl 5.10.
1277    
1278    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1279        pattern matches a fixed length string. PCRE did not allow this; now it
1280        does. Neither allows recursion.
1281    
1282    25. I finally figured out how to implement a request to provide the minimum
1283        length of subject string that was needed in order to match a given pattern.
1284        (It was back references and recursion that I had previously got hung up
1285        on.) This code has now been added to pcre_study(); it finds a lower bound
1286        to the length of subject needed. It is not necessarily the greatest lower
1287        bound, but using it to avoid searching strings that are too short does give
1288        some useful speed-ups. The value is available to calling programs via
1289        pcre_fullinfo().
1290    
1291    26. While implementing 25, I discovered to my embarrassment that pcretest had
1292        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1293        study optimizations had never been tested with that matching function.
1294        Oops. What is worse, even when it was passed study data, there was a bug in
1295        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1296        were also very few tests of studied patterns with pcre_dfa_exec().
1297    
1298    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1299        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1300        on the other side of the coin, they are no longer allowed to have different
1301        names, because these cannot be distinguished in PCRE, and this has caused
1302        confusion. (This is a difference from Perl.)
1303    
1304    28. When duplicate subpattern names are present (necessarily with different
1305        numbers, as required by 27 above), and a test is made by name in a
1306        conditional pattern, either for a subpattern having been matched, or for
1307        recursion in such a pattern, all the associated numbered subpatterns are
1308        tested, and the overall condition is true if the condition is true for any
1309        one of them. This is the way Perl works, and is also more like the way
1310        testing by number works.
1311    
1312    
1313  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1314  ---------------------  ---------------------

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