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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.32
5    ------------
6    
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
9    
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
12    
13    3.  Single character iterator optimizations in the JIT compiler.
14    
15    4.  Improved JIT compiler optimizations for character ranges.
16    
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
19    
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
24    
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
27    
28    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
29        grep:
30    
31        (a) There is now no limit to the number of patterns to be matched.
32    
33        (b) An error is given if a pattern is too long.
34    
35        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
36            are now supported.
37    
38        (d) --exclude-from and --include-from (multiple use) have been added.
39    
40        (e) Exclusions and inclusions now apply to all files and directories, not
41            just to those obtained from scanning a directory recursively.
42    
43        (f) Multiple uses of -f and --file-list are now supported.
44    
45        (g) In a Windows environment, the default for -d has been changed from
46            "read" (the GNU grep default) to "skip", because otherwise the presence
47            of a directory in the file list provokes an error.
48    
49        (h) The documentation has been revised and clarified in places.
50    
51    9.  Improve the matching speed of capturing brackets.
52    
53    10. Changed the meaning of \X so that it now matches a Unicode extended
54        grapheme cluster.
55    
56    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
57        out POSIX threads when JIT support is configured.
58    
59    
60    
61    Version 8.31 06-July-2012
62    -------------------------
63    
64    1.  Fixing a wrong JIT test case and some compiler warnings.
65    
66    2.  Removed a bashism from the RunTest script.
67    
68    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
69        to unsigned type, result still unsigned" that was given by an MS compiler
70        on encountering the code "-sizeof(xxx)".
71    
72    4.  Partial matching support is added to the JIT compiler.
73    
74    5.  Fixed several bugs concerned with partial matching of items that consist
75        of more than one character:
76    
77        (a) /^(..)\1/ did not partially match "aba" because checking references was
78            done on an "all or nothing" basis. This also applied to repeated
79            references.
80    
81        (b) \R did not give a hard partial match if \r was found at the end of the
82            subject.
83    
84        (c) \X did not give a hard partial match after matching one or more
85            characters at the end of the subject.
86    
87        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
88            a partial match for the string "\r".
89    
90        (e) When newline was set to CRLF, the metacharacter "." did not recognize
91            a partial match for a CR character at the end of the subject string.
92    
93    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
94        running pcretest, the text "(JIT)" added to the output whenever JIT is
95        actually used to run the match.
96    
97    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
98        or /S+[+] with a digit between 1 and 7.
99    
100    8.  OP_NOT now supports any UTF character not just single-byte ones.
101    
102    9.  (*MARK) control verb is now supported by the JIT compiler.
103    
104    10. The command "./RunTest list" lists the available tests without actually
105        running any of them. (Because I keep forgetting what they all are.)
106    
107    11. Add PCRE_INFO_MAXLOOKBEHIND.
108    
109    12. Applied a (slightly modified) user-supplied patch that improves performance
110        when the heap is used for recursion (compiled with --disable-stack-for-
111        recursion). Instead of malloc and free for each heap frame each time a
112        logical recursion happens, frames are retained on a chain and re-used where
113        possible. This sometimes gives as much as 30% improvement.
114    
115    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
116        call.
117    
118    14. As documented, (*COMMIT) is now confined to within a positive assertion.
119    
120    15. It is now possible to link pcretest with libedit as an alternative to
121        libreadline.
122    
123    16. (*COMMIT) control verb is now supported by the JIT compiler.
124    
125    17. The Unicode data tables have been updated to Unicode 6.1.0.
126    
127    18. Added --file-list option to pcregrep.
128    
129    19. Added binary file support to pcregrep, including the -a, --binary-files,
130        -I, and --text options.
131    
132    20. The madvise function is renamed for posix_madvise for QNX compatibility
133        reasons. Fixed by Giuseppe D'Angelo.
134    
135    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
136    
137    22. Changed the option for creating symbolic links for 16-bit man pages from
138        -s to -sf so that re-installing does not cause issues.
139    
140    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
141    
142    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
143        matches in certain environments (the workspace was not being correctly
144        retained). Also added to pcre_dfa_exec() a simple plausibility check on
145        some of the workspace data at the beginning of a restart.
146    
147    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
148        was not doing so when it should - probably a typo introduced by SVN 528
149        (change 8.10/14).
150    
151    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
152        \w+ when the character tables indicated that \x{c4} was a word character.
153        There were several related cases, all because the tests for doing a table
154        lookup were testing for characters less than 127 instead of 255.
155    
156    27. If a pattern contains capturing parentheses that are not used in a match,
157        their slots in the ovector are set to -1. For those that are higher than
158        any matched groups, this happens at the end of processing. In the case when
159        there were back references that the ovector was too small to contain
160        (causing temporary malloc'd memory to be used during matching), and the
161        highest capturing number was not used, memory off the end of the ovector
162        was incorrectly being set to -1. (It was using the size of the temporary
163        memory instead of the true size.)
164    
165    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
166        ovector size, it uses memory at the end of the block that it has got.
167    
168    29. Check for an overlong MARK name and give an error at compile time. The
169        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
170    
171    30. JIT compiler update.
172    
173    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
174        Rill for the patch.
175    
176    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
177    
178    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
179    
180    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
181        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
182        was enabled.
183    
184    35. Improve JIT code generation for greedy plus quantifier.
185    
186    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
187        1 to "aa" instead of to an empty string. The bug affected repeated groups
188        that could potentially match an empty string.
189    
190    37. Optimizing single character iterators in JIT.
191    
192    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
193        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
194        codepoints that are too big for the mode are faulted, and in a UTF mode,
195        disallowed codepoints are also faulted.
196    
197    39. If PCRE was compiled with UTF support, in three places in the DFA
198        matcher there was code that should only have been obeyed in UTF mode, but
199        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
200        processing when bytes with values greater than 127 were present. In 16-bit
201        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
202        both cases the values are those that cannot be the first data item in a UTF
203        character. The three items that might have provoked this were recursions,
204        possessively repeated groups, and atomic groups.
205    
206    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
207        and pcregrep, because some OS require shared objects to be explicitly
208        passed to ld, causing the link step to fail if they are not.
209    
210    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
211        mode, patterns that started with \h* or \R* might be incorrectly matched.
212    
213    
214    Version 8.30 04-February-2012
215    -----------------------------
216    
217    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
218        name is defined in ctype.h.
219    
220    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
221        only in quite long subpatterns.
222    
223    3.  Removed the function pcre_info(), which has been obsolete and deprecated
224        since it was replaced by pcre_fullinfo() in February 2000.
225    
226    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
227        match a (*MARK), and the match failed at the start of the subject, a
228        reference to memory before the start of the subject could occur. This bug
229        was introduced by fix 17 of release 8.21.
230    
231    5.  A reference to an unset group with zero minimum repetition was giving
232        totally wrong answers (in non-JavaScript-compatibility mode). For example,
233        /(another)?(\1?)test/ matched against "hello world test". This bug was
234        introduced in release 8.13.
235    
236    6.  Add support for 16-bit character strings (a large amount of work involving
237        many changes and refactorings).
238    
239    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
240        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
241        from a file.
242    
243    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
244        rounding is not applied in this particular case).
245    
246    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
247        if they appear, or are escaped, in patterns.
248    
249    10. Get rid of a number of -Wunused-but-set-variable warnings.
250    
251    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
252        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
253        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
254        also returns the mark "x". This bug applied to capturing parentheses,
255        non-capturing parentheses, and atomic parentheses. It also applied to some
256        assertions.
257    
258    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
259        information out of configure.ac instead of relying on pcre.h.generic, which
260        is not stored in the repository.
261    
262    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
263        -lreadline.
264    
265    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
266    
267    15. Applied Graycode's patch to put the top-level frame on the stack rather
268        than the heap when not using the stack for recursion. This gives a
269        performance improvement in many cases when recursion is not deep.
270    
271    16. Experimental code added to "pcretest -C" to output the stack frame size.
272    
273    
274    Version 8.21 12-Dec-2011
275    ------------------------
276    
277    1.  Updating the JIT compiler.
278    
279    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
280        are added as well.
281    
282    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
283        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
284        calling _pcre_jit_exec. Some extra comments are added.
285    
286    4.  (*MARK) settings inside atomic groups that do not contain any capturing
287        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
288        was introduced by change 18 for 8.20.
289    
290    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
291        ECMA-262 standard.
292    
293    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
294        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
295        This bug was probably introduced by change 9 of 8.13.
296    
297    7.  While fixing 6 above, I noticed that a number of other items were being
298        incorrectly rejected as "not fixed length". This arose partly because newer
299        opcodes had not been added to the fixed-length checking code. I have (a)
300        corrected the bug and added tests for these items, and (b) arranged for an
301        error to occur if an unknown opcode is encountered while checking for fixed
302        length instead of just assuming "not fixed length". The items that were
303        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
304        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
305        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
306    
307    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
308        being incorrectly compiled and would have given unpredicatble results.
309    
310    9.  A possessively repeated subpattern with minimum repeat count greater than
311        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
312        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
313        the first (A) could occur when it should not.
314    
315    10. Add a cast and remove a redundant test from the code.
316    
317    11. JIT should use pcre_malloc/pcre_free for allocation.
318    
319    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
320        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
321        is anything other than /usr, -L is still shown).
322    
323    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
324    
325    14. Perl does not support \N without a following name in a [] class; PCRE now
326        also gives an error.
327    
328    15. If a forward reference was repeated with an upper limit of around 2000,
329        it caused the error "internal error: overran compiling workspace". The
330        maximum number of forward references (including repeats) was limited by the
331        internal workspace, and dependent on the LINK_SIZE. The code has been
332        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
333        the default depends on LINK_SIZE. There is a new upper limit (for safety)
334        of around 200,000 forward references. While doing this, I also speeded up
335        the filling in of repeated forward references.
336    
337    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
338        incorrectly expecting the subject to contain another "a" after the start.
339    
340    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
341        in the match, the SKIP should be ignored. This was not happening; instead
342        the SKIP was being treated as NOMATCH. For patterns such as
343        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
344        tested.
345    
346    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
347        now much more compatible with Perl, in particular in cases where the result
348        is a non-match for a non-anchored pattern. For example, if
349        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
350        "m", where previously it did not return a name. A side effect of this
351        change is that for partial matches, the last encountered mark name is
352        returned, as for non matches. A number of tests that were previously not
353        Perl-compatible have been moved into the Perl-compatible test files. The
354        refactoring has had the pleasing side effect of removing one argument from
355        the match() function, thus reducing its stack requirements.
356    
357    19. If the /S+ option was used in pcretest to study a pattern using JIT,
358        subsequent uses of /S (without +) incorrectly behaved like /S+.
359    
360    21. Retrieve executable code size support for the JIT compiler and fixing
361        some warnings.
362    
363    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
364        not work when the shorter character appeared right at the end of the
365        subject string.
366    
367    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
368        systems.
369    
370    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
371        output it when the /M option is used in pcretest.
372    
373    25. The CheckMan script was not being included in the distribution. Also, added
374        an explicit "perl" to run Perl scripts from the PrepareRelease script
375        because this is reportedly needed in Windows.
376    
377    26. If study data was being save in a file and studying had not found a set of
378        "starts with" bytes for the pattern, the data written to the file (though
379        never used) was taken from uninitialized memory and so caused valgrind to
380        complain.
381    
382    27. Updated RunTest.bat as provided by Sheri Pierce.
383    
384    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
385    
386    29. Computation of memory usage for the table of capturing group names was
387        giving an unnecessarily large value.
388    
389    
390    Version 8.20 21-Oct-2011
391    ------------------------
392    
393    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
394        a POSIX class. After further experiments with Perl, which convinced me that
395        Perl has bugs and confusions, a closing square bracket is no longer allowed
396        in a POSIX name. This bug also affected patterns with classes that started
397        with full stops.
398    
399    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
400        captured substring, but while checking the failing first alternative,
401        substring 1 is temporarily captured. If the output vector supplied to
402        pcre_exec() was not big enough for this capture, the yield of the function
403        was still zero ("insufficient space for captured substrings"). This cannot
404        be totally fixed without adding another stack variable, which seems a lot
405        of expense for a edge case. However, I have improved the situation in cases
406        such as /(a)(b)x|abc/ matched against "abc", where the return code
407        indicates that fewer than the maximum number of slots in the ovector have
408        been set.
409    
410    3.  Related to (2) above: when there are more back references in a pattern than
411        slots in the output vector, pcre_exec() uses temporary memory during
412        matching, and copies in the captures as far as possible afterwards. It was
413        using the entire output vector, but this conflicts with the specification
414        that only 2/3 is used for passing back captured substrings. Now it uses
415        only the first 2/3, for compatibility. This is, of course, another edge
416        case.
417    
418    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
419        main code base, and can be used by building with --enable-jit. When this is
420        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
421        runtime --no-jit option is given.
422    
423    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
424        ovector, the return from the function was zero, implying that there were
425        other matches that did not fit. The correct "exactly full" value is now
426        returned.
427    
428    6.  If a subpattern that was called recursively or as a subroutine contained
429        (*PRUNE) or any other control that caused it to give a non-standard return,
430        invalid errors such as "Error -26 (nested recursion at the same subject
431        position)" or even infinite loops could occur.
432    
433    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
434        computing the minimum length on reaching *ACCEPT, and so ended up with the
435        wrong value of 1 rather than 0. Further investigation indicates that
436        computing a minimum subject length in the presence of *ACCEPT is difficult
437        (think back references, subroutine calls), and so I have changed the code
438        so that no minimum is registered for a pattern that contains *ACCEPT.
439    
440    8.  If (*THEN) was present in the first (true) branch of a conditional group,
441        it was not handled as intended. [But see 16 below.]
442    
443    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
444        Sheri Pierce.
445    
446    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
447        the first byte in a match must be "a".
448    
449    11. Change 17 for 8.13 increased the recursion depth for patterns like
450        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
451        pattern contains any instances of (*THEN). If it does not, the old
452        optimizations are restored. It would be nice to do this on a per-group
453        basis, but at the moment that is not feasible.
454    
455    12. In some environments, the output of pcretest -C is CRLF terminated. This
456        broke RunTest's code that checks for the link size. A single white space
457        character after the value is now allowed for.
458    
459    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
460        For "fr", it uses the Windows-specific input and output files.
461    
462    14. If (*THEN) appeared in a group that was called recursively or as a
463        subroutine, it did not work as intended. [But see next item.]
464    
465    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
466        pattern fragments (but not containing any | characters). If A and B are
467        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
468        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
469        D. In other words, Perl considers parentheses that do not contain any |
470        characters to be part of a surrounding alternative, whereas PCRE was
471        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
472        differently. PCRE now behaves in the same way as Perl, except in the case
473        of subroutine/recursion calls such as (?1) which have in any case always
474        been different (but PCRE had them first :-).
475    
476    16. Related to 15 above: Perl does not treat the | in a conditional group as
477        creating alternatives. Such a group is treated in the same way as an
478        ordinary group without any | characters when processing (*THEN). PCRE has
479        been changed to match Perl's behaviour.
480    
481    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
482        RunGrepTest script failed.
483    
484    18. Change 22 for version 13 caused atomic groups to use more stack. This is
485        inevitable for groups that contain captures, but it can lead to a lot of
486        stack use in large patterns. The old behaviour has been restored for atomic
487        groups that do not contain any capturing parentheses.
488    
489    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
490        suppress the check for a minimum subject length at run time. (If it was
491        given to pcre_exec() or pcre_dfa_exec() it did work.)
492    
493    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
494        fail to work when decoding hex characters in data strings in EBCDIC
495        environments.
496    
497    21. It appears that in at least one Mac OS environment, the isxdigit() function
498        is implemented as a macro that evaluates to its argument more than once,
499        contravening the C 90 Standard (I haven't checked a later standard). There
500        was an instance in pcretest which caused it to go wrong when processing
501        \x{...} escapes in subject strings. The has been rewritten to avoid using
502        things like p++ in the argument of isxdigit().
503    
504    
505    Version 8.13 16-Aug-2011
506    ------------------------
507    
508    1.  The Unicode data tables have been updated to Unicode 6.0.0.
509    
510    2.  Two minor typos in pcre_internal.h have been fixed.
511    
512    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
513        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
514        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
515    
516    4.  There were a number of related bugs in the code for matching backrefences
517        caselessly in UTF-8 mode when codes for the characters concerned were
518        different numbers of bytes. For example, U+023A and U+2C65 are an upper
519        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
520        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
521        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
522        2-byte code at the end of the subject (it thought there wasn't enough data
523        left).
524    
525    5.  Comprehensive information about what went wrong is now returned by
526        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
527        as the output vector has at least 2 elements. The offset of the start of
528        the failing character and a reason code are placed in the vector.
529    
530    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
531        now returned is for the first byte of the failing character, instead of the
532        last byte inspected. This is an incompatible change, but I hope it is small
533        enough not to be a problem. It makes the returned offset consistent with
534        pcre_exec() and pcre_dfa_exec().
535    
536    7.  pcretest now gives a text phrase as well as the error number when
537        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
538        failure, the offset and reason code are output.
539    
540    8.  When \R was used with a maximizing quantifier it failed to skip backwards
541        over a \r\n pair if the subsequent match failed. Instead, it just skipped
542        back over a single character (\n). This seems wrong (because it treated the
543        two characters as a single entity when going forwards), conflicts with the
544        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
545        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
546        has been changed.
547    
548    9.  Some internal refactoring has changed the processing so that the handling
549        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
550        time (the PCRE_DOTALL option was changed this way some time ago: version
551        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
552        which was always a bit of a fudge. It also means that there is one less
553        argument for the match() function, which reduces its stack requirements
554        slightly. This change also fixes an incompatibility with Perl: the pattern
555        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
556    
557    10. More internal refactoring has drastically reduced the number of recursive
558        calls to match() for possessively repeated groups such as (abc)++ when
559        using pcre_exec().
560    
561    11. While implementing 10, a number of bugs in the handling of groups were
562        discovered and fixed:
563    
564        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
565        (a|)*(?1) gave a compile-time internal error.
566        ((a|)+)+  did not notice that the outer group could match an empty string.
567        (^a|^)+   was not marked as anchored.
568        (.*a|.*)+ was not marked as matching at start or after a newline.
569    
570    12. Yet more internal refactoring has removed another argument from the match()
571        function. Special calls to this function are now indicated by setting a
572        value in a variable in the "match data" data block.
573    
574    13. Be more explicit in pcre_study() instead of relying on "default" for
575        opcodes that mean there is no starting character; this means that when new
576        ones are added and accidentally left out of pcre_study(), testing should
577        pick them up.
578    
579    14. The -s option of pcretest has been documented for ages as being an old
580        synonym of -m (show memory usage). I have changed it to mean "force study
581        for every regex", that is, assume /S for every regex. This is similar to -i
582        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
583        using it. It makes it easier to run collections of tests with and without
584        study enabled, and thereby test pcre_study() more easily. All the standard
585        tests are now run with and without -s (but some patterns can be marked as
586        "never study" - see 20 below).
587    
588    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
589        restoration of the capturing data to the outer values was not happening
590        correctly.
591    
592    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
593        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
594        pattern had matched an empty string, and so incorrectly returned a no
595        match.
596    
597    17. There was optimizing code for the last branch of non-capturing parentheses,
598        and also for the obeyed branch of a conditional subexpression, which used
599        tail recursion to cut down on stack usage. Unfortunately, now that there is
600        the possibility of (*THEN) occurring in these branches, tail recursion is
601        no longer possible because the return has to be checked for (*THEN). These
602        two optimizations have therefore been removed. [But see 8.20/11 above.]
603    
604    18. If a pattern containing \R was studied, it was assumed that \R always
605        matched two bytes, thus causing the minimum subject length to be
606        incorrectly computed because \R can also match just one byte.
607    
608    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
609        was incorrectly computed.
610    
611    20. If /S is present twice on a test pattern in pcretest input, it now
612        *disables* studying, thereby overriding the use of -s on the command line
613        (see 14 above). This is necessary for one or two tests to keep the output
614        identical in both cases.
615    
616    21. When (*ACCEPT) was used in an assertion that matched an empty string and
617        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
618    
619    22. When an atomic group that contained a capturing parenthesis was
620        successfully matched, but the branch in which it appeared failed, the
621        capturing was not being forgotten if a higher numbered group was later
622        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
623        group 1 to "a", when in fact it should be unset. This applied to multi-
624        branched capturing and non-capturing groups, repeated or not, and also to
625        positive assertions (capturing in negative assertions does not happen
626        in PCRE) and also to nested atomic groups.
627    
628    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
629        subject after a captured substring, to make it easier to tell which of a
630        number of identical substrings has been captured.
631    
632    24. The way atomic groups are processed by pcre_exec() has been changed so that
633        if they are repeated, backtracking one repetition now resets captured
634        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
635        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
636        "aaa". Previously, it would have been "a". As part of this code
637        refactoring, the way recursive calls are handled has also been changed.
638    
639    25. If an assertion condition captured any substrings, they were not passed
640        back unless some other capturing happened later. For example, if
641        (?(?=(a))a) was matched against "a", no capturing was returned.
642    
643    26. When studying a pattern that contained subroutine calls or assertions,
644        the code for finding the minimum length of a possible match was handling
645        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
646        group 1 called group 2 while simultaneously a separate group 2 called group
647        1). A stack overflow occurred in this case. I have fixed this by limiting
648        the recursion depth to 10.
649    
650    27. Updated RunTest.bat in the distribution to the version supplied by Tom
651        Fortmann. This supports explicit test numbers on the command line, and has
652        argument validation and error reporting.
653    
654    28. An instance of \X with an unlimited repeat could fail if at any point the
655        first character it looked at was a mark character.
656    
657    29. Some minor code refactoring concerning Unicode properties and scripts
658        should reduce the stack requirement of match() slightly.
659    
660    30. Added the '=' option to pcretest to check the setting of unused capturing
661        slots at the end of the pattern, which are documented as being -1, but are
662        not included in the return count.
663    
664    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
665        compiled something random. Now it gives a compile-time error (as does
666        Perl).
667    
668    32. A *MARK encountered during the processing of a positive assertion is now
669        recorded and passed back (compatible with Perl).
670    
671    33. If --only-matching or --colour was set on a pcregrep call whose pattern
672        had alternative anchored branches, the search for a second match in a line
673        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
674        matched the line "0102" twice. The same bug affected patterns that started
675        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
676        twice.
677    
678    34. Previously, PCRE did not allow quantification of assertions. However, Perl
679        does, and because of capturing effects, quantifying parenthesized
680        assertions may at times be useful. Quantifiers are now allowed for
681        parenthesized assertions.
682    
683    35. A minor code tidy in pcre_compile() when checking options for \R usage.
684    
685    36. \g was being checked for fancy things in a character class, when it should
686        just be a literal "g".
687    
688    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
689        appearance of a nested POSIX class supersedes an apparent external class.
690        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
691        unescaped square brackets may also appear as part of class names. For
692        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
693        more like Perl. (But see 8.20/1 above.)
694    
695    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
696        was because it thought it was \N{name}, which is not supported).
697    
698    39. Add minix to OS list not supporting the -S option in pcretest.
699    
700    40. PCRE tries to detect cases of infinite recursion at compile time, but it
701        cannot analyze patterns in sufficient detail to catch mutual recursions
702        such as ((?1))((?2)). There is now a runtime test that gives an error if a
703        subgroup is called recursively as a subpattern for a second time at the
704        same position in the subject string. In previous releases this might have
705        been caught by the recursion limit, or it might have run out of stack.
706    
707    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
708        happen only once. PCRE was, however incorrectly giving a compile time error
709        "recursive call could loop indefinitely" because it cannot analyze the
710        pattern in sufficient detail. The compile time test no longer happens when
711        PCRE is compiling a conditional subpattern, but actual runaway loops are
712        now caught at runtime (see 40 above).
713    
714    42. It seems that Perl allows any characters other than a closing parenthesis
715        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
716        has been changed to be the same.
717    
718    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
719        as not to get warnings when autogen.sh is called. Also changed
720        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
721    
722    44. To help people who use pcregrep to scan files containing exceedingly long
723        lines, the following changes have been made:
724    
725        (a) The default value of the buffer size parameter has been increased from
726            8K to 20K. (The actual buffer used is three times this size.)
727    
728        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
729            PCRE is built.
730    
731        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
732            to be set at run time.
733    
734        (d) Numerical values in pcregrep options can be followed by K or M, for
735            example --buffer-size=50K.
736    
737        (e) If a line being scanned overflows pcregrep's buffer, an error is now
738            given and the return code is set to 2.
739    
740    45. Add a pointer to the latest mark to the callout data block.
741    
742    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
743        partial match of an empty string instead of no match. This was specific to
744        the use of ".".
745    
746    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
747        complete match instead of a partial match. This bug was dependent on both
748        the PCRE_UTF8 and PCRE_DOTALL options being set.
749    
750    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
751        starting byte set, because \b was not being ignored.
752    
753    
754    Version 8.12 15-Jan-2011
755    ------------------------
756    
757    1.  Fixed some typos in the markup of the man pages, and wrote a script that
758        checks for such things as part of the documentation building process.
759    
760    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
761        --match-limit and --recursion-limit options (added for 8.11). In
762        particular, this made one of the standard tests fail. (The integer value
763        went into the wrong half of a long int.)
764    
765    3.  If the --colour option was given to pcregrep with -v (invert match), it
766        did strange things, either producing crazy output, or crashing. It should,
767        of course, ignore a request for colour when reporting lines that do not
768        match.
769    
770    4.  Another pcregrep bug caused similar problems if --colour was specified with
771        -M (multiline) and the pattern match finished with a line ending.
772    
773    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
774        matched in multiline mode, the following line was shown as part of the
775        match. This seems wrong, so I have changed it.
776    
777    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
778        the check for further matches in the same line (so they could be coloured)
779        to overrun the end of the current line. If another match was found, it was
780        incorrectly shown (and then shown again when found in the next line).
781    
782    7.  If pcregrep was compiled under Windows, there was a reference to the
783        function pcregrep_exit() before it was defined. I am assuming this was
784        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
785        reported by a user. I've moved the definition above the reference.
786    
787    
788    Version 8.11 10-Dec-2010
789    ------------------------
790    
791    1.  (*THEN) was not working properly if there were untried alternatives prior
792        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
793        backtracked to try for "b" instead of moving to the next alternative branch
794        at the same level (in this case, to look for "c"). The Perl documentation
795        is clear that when (*THEN) is backtracked onto, it goes to the "next
796        alternative in the innermost enclosing group".
797    
798    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
799        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
800        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
801        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
802        (*THEN).
803    
804    3.  If \s appeared in a character class, it removed the VT character from
805        the class, even if it had been included by some previous item, for example
806        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
807        of \s, but is part of the POSIX "space" class.)
808    
809    4.  A partial match never returns an empty string (because you can always
810        match an empty string at the end of the subject); however the checking for
811        an empty string was starting at the "start of match" point. This has been
812        changed to the "earliest inspected character" point, because the returned
813        data for a partial match starts at this character. This means that, for
814        example, /(?<=abc)def/ gives a partial match for the subject "abc"
815        (previously it gave "no match").
816    
817    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
818        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
819        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
820        has an implication that the given string is incomplete (because a partial
821        match is preferred over a full match). For this reason, these items now
822        give a partial match in this situation. [Aside: previously, the one case
823        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
824        match rather than a full match, which was wrong by the old rules, but is
825        now correct.]
826    
827    6.  There was a bug in the handling of #-introduced comments, recognized when
828        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
829        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
830        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
831        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
832        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
833        places in pcre_compile().
834    
835    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
836        comments when looking ahead for named forward references to subpatterns,
837        the only newline sequence it recognized was NL. It now handles newlines
838        according to the set newline convention.
839    
840    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
841        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
842        cater for a lack of strerror(). These oversights have been fixed.
843    
844    9.  Added --match-limit and --recursion-limit to pcregrep.
845    
846    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
847    
848    11. When the -o option was used, pcregrep was setting a return code of 1, even
849        when matches were found, and --line-buffered was not being honoured.
850    
851    12. Added an optional parentheses number to the -o and --only-matching options
852        of pcregrep.
853    
854    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
855        can match an empty string. The code to do it in pcretest and pcredemo
856        needed fixing:
857    
858        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
859            only one byte after an empty string match just before CRLF (this case
860            just got forgotten; "any" and "anycrlf" were OK).
861    
862        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
863            mode when an empty string match preceded an ASCII character followed by
864            a non-ASCII character. (The code for advancing by one character rather
865            than one byte was nonsense.)
866    
867        (c) The pcredemo.c sample program did not have any code at all to handle
868            the cases when CRLF is a valid newline sequence.
869    
870    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
871        as a starting offset was within the subject string. There is now a new
872        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
873        negative or greater than the length of the string. In order to test this,
874        pcretest is extended to allow the setting of negative starting offsets.
875    
876    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
877        starting offset points to the beginning of a UTF-8 character was
878        unnecessarily clumsy. I tidied it up.
879    
880    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
881        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
882    
883    17. Nobody had reported that the --include_dir option, which was added in
884        release 7.7 should have been called --include-dir (hyphen, not underscore)
885        for compatibility with GNU grep. I have changed it to --include-dir, but
886        left --include_dir as an undocumented synonym, and the same for
887        --exclude-dir, though that is not available in GNU grep, at least as of
888        release 2.5.4.
889    
890    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
891        characters from a string of bytes) have been redefined so as not to use
892        loops, in order to improve performance in some environments. At the same
893        time, I abstracted some of the common code into auxiliary macros to save
894        repetition (this should not affect the compiled code).
895    
896    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
897        compile-time error is now given if \c is not followed by an ASCII
898        character, that is, a byte less than 128. (In EBCDIC mode, the code is
899        different, and any byte value is allowed.)
900    
901    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
902        START_OPTIMIZE option, which is now allowed at compile time - but just
903        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
904        to pcregrep and other applications that have no direct access to PCRE
905        options. The new /Y option in pcretest sets this option when calling
906        pcre_compile().
907    
908    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
909        back references. Groups containing recursive back references were forced to
910        be atomic by that change, but in the case of named groups, the amount of
911        memory required was incorrectly computed, leading to "Failed: internal
912        error: code overflow". This has been fixed.
913    
914    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
915        pcretest.c, to avoid build problems in some Borland environments.
916    
917    
918    Version 8.10 25-Jun-2010
919    ------------------------
920    
921    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
922        THEN.
923    
924    2.  (*ACCEPT) was not working when inside an atomic group.
925    
926    3.  Inside a character class, \B is treated as a literal by default, but
927        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
928        causes the error). The code is unchanged, but I tidied the documentation.
929    
930    4.  Inside a character class, PCRE always treated \R and \X as literals,
931        whereas Perl faults them if its -w option is set. I have changed PCRE so
932        that it faults them when PCRE_EXTRA is set.
933    
934    5.  Added support for \N, which always matches any character other than
935        newline. (It is the same as "." when PCRE_DOTALL is not set.)
936    
937    6.  When compiling pcregrep with newer versions of gcc which may have
938        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
939        declared with attribute warn_unused_result" were given. Just casting the
940        result to (void) does not stop the warnings; a more elaborate fudge is
941        needed. I've used a macro to implement this.
942    
943    7.  Minor change to pcretest.c to avoid a compiler warning.
944    
945    8.  Added four artifical Unicode properties to help with an option to make
946        \s etc use properties (see next item). The new properties are: Xan
947        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
948    
949    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
950        use Unicode properties. (*UCP) at the start of a pattern can be used to set
951        this option. Modified pcretest to add /W to test this facility. Added
952        REG_UCP to make it available via the POSIX interface.
953    
954    10. Added --line-buffered to pcregrep.
955    
956    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
957        studied, and the match started with a letter with a code point greater than
958        127 whose first byte was different to the first byte of the other case of
959        the letter, the other case of this starting letter was not recognized
960        (#976).
961    
962    12. If a pattern that was studied started with a repeated Unicode property
963        test, for example, \p{Nd}+, there was the theoretical possibility of
964        setting up an incorrect bitmap of starting bytes, but fortunately it could
965        not have actually happened in practice until change 8 above was made (it
966        added property types that matched character-matching opcodes).
967    
968    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
969        possible starting bytes for non-anchored patterns.
970    
971    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
972        \R, and also a number of cases that involve Unicode properties, both
973        explicit and implicit when PCRE_UCP is set.
974    
975    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
976        input, it could crash or give wrong results if characters with values
977        greater than 0xc0 were present in the subject string. (Detail: it assumed
978        UTF-8 input when processing these items.)
979    
980    16. Added a lot of (int) casts to avoid compiler warnings in systems where
981        size_t is 64-bit (#991).
982    
983    17. Added a check for running out of memory when PCRE is compiled with
984        --disable-stack-for-recursion (#990).
985    
986    18. If the last data line in a file for pcretest does not have a newline on
987        the end, a newline was missing in the output.
988    
989    19. The default pcre_chartables.c file recognizes only ASCII characters (values
990        less than 128) in its various bitmaps. However, there is a facility for
991        generating tables according to the current locale when PCRE is compiled. It
992        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
993        characters, are recognized by isspace() and therefore were getting set in
994        these tables, and indeed these tables seem to approximate to ISO 8859. This
995        caused a problem in UTF-8 mode when pcre_study() was used to create a list
996        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
997        which of course cannot start UTF-8 characters. I have changed the code so
998        that only real ASCII characters (less than 128) and the correct starting
999        bytes for UTF-8 encodings are set for characters greater than 127 when in
1000        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1001        altogether.)
1002    
1003    20. Added the /T option to pcretest so as to be able to run tests with non-
1004        standard character tables, thus making it possible to include the tests
1005        used for 19 above in the standard set of tests.
1006    
1007    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1008        reference to a subpattern the other side of a comment that contains an
1009        opening parenthesis caused either an internal compiling error, or a
1010        reference to the wrong subpattern.
1011    
1012    
1013    Version 8.02 19-Mar-2010
1014    ------------------------
1015    
1016    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1017    
1018    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1019        configured.
1020    
1021    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1022        original author of that file, following a query about its status.
1023    
1024    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1025        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1026    
1027    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1028        quantifier applied to a forward-referencing subroutine call, could compile
1029        incorrect code or give the error "internal error: previously-checked
1030        referenced subpattern not found".
1031    
1032    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1033        variables to point to external functions. For these systems, therefore,
1034        pcre_malloc etc. are now initialized to local functions that call the
1035        relevant global functions.
1036    
1037    7.  There were two entries missing in the vectors called coptable and poptable
1038        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1039        I've fixed the data, and added a kludgy way of testing at compile time that
1040        the lengths are correct (equal to the number of opcodes).
1041    
1042    8.  Following on from 7, I added a similar kludge to check the length of the
1043        eint vector in pcreposix.c.
1044    
1045    9.  Error texts for pcre_compile() are held as one long string to avoid too
1046        much relocation at load time. To find a text, the string is searched,
1047        counting zeros. There was no check for running off the end of the string,
1048        which could happen if a new error number was added without updating the
1049        string.
1050    
1051    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1052    
1053    11. \K was not working if it appeared in an atomic group or in a group that
1054        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1055        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1056        the assertion is positive, but not if it is negative.
1057    
1058    12. Change 11 fortuitously reduced the size of the stack frame used in the
1059        "match()" function of pcre_exec.c by one pointer. Forthcoming
1060        implementation of support for (*MARK) will need an extra pointer on the
1061        stack; I have reserved it now, so that the stack frame size does not
1062        decrease.
1063    
1064    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1065        item in branch that calls a recursion is a subroutine call - as in the
1066        second branch in the above example - was incorrectly given the compile-
1067        time error "recursive call could loop indefinitely" because pcre_compile()
1068        was not correctly checking the subroutine for matching a non-empty string.
1069    
1070    14. The checks for overrunning compiling workspace could trigger after an
1071        overrun had occurred. This is a "should never occur" error, but it can be
1072        triggered by pathological patterns such as hundreds of nested parentheses.
1073        The checks now trigger 100 bytes before the end of the workspace.
1074    
1075    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1076    
1077    
1078    Version 8.01 19-Jan-2010
1079    ------------------------
1080    
1081    1.  If a pattern contained a conditional subpattern with only one branch (in
1082        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1083        computed the wrong minimum data length (which is of course zero for such
1084        subpatterns). This could cause incorrect "no match" results.
1085    
1086    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1087        the pattern is reset in the first branch, pcre_compile() failed with
1088        "internal error: code overflow at offset...". This happened only when
1089        the reset was to the original external option setting. (An optimization
1090        abstracts leading options settings into an external setting, which was the
1091        cause of this.)
1092    
1093    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1094        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1095        assertion pattern did not match (meaning that the assertion was true), it
1096        was incorrectly treated as false if the SKIP had been reached during the
1097        matching. This also applied to assertions used as conditions.
1098    
1099    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1100        assertion subpattern, including such a pattern used as a condition,
1101        unpredictable results occurred, instead of the error return
1102        PCRE_ERROR_DFA_UITEM.
1103    
1104    5.  The C++ GlobalReplace function was not working like Perl for the special
1105        situation when an empty string is matched. It now does the fancy magic
1106        stuff that is necessary.
1107    
1108    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1109        removed. (These were left over from very, very early versions of PCRE.)
1110    
1111    7.  Some cosmetic changes to the code to make life easier when compiling it
1112        as part of something else:
1113    
1114        (a) Change DEBUG to PCRE_DEBUG.
1115    
1116        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1117            called "current" as "current_branch", to prevent a collision with the
1118            Linux macro when compiled as a kernel module.
1119    
1120        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1121            prevent a collision with the Linux macro when compiled as a kernel
1122            module.
1123    
1124    8.  In pcre_compile() there are some checks for integer overflows that used to
1125        cast potentially large values to (double). This has been changed to that
1126        when building, a check for int64_t is made, and if it is found, it is used
1127        instead, thus avoiding the use of floating point arithmetic. (There is no
1128        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1129        double.
1130    
1131    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1132        2005 (difference between two addresses compared to an unsigned value).
1133    
1134    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1135        custom one, because of the following reported problem in Windows:
1136    
1137          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1138              under Win32.
1139          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1140              therefore missing the function definition.
1141          - The compiler thus generates a "C" signature for the test function.
1142          - The linker fails to find the "C" function.
1143          - PCRE fails to configure if asked to do so against libbz2.
1144    
1145    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1146        messages were output:
1147    
1148          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1149          rerunning libtoolize, to keep the correct libtool macros in-tree.
1150          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1151    
1152        I have done both of these things.
1153    
1154    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1155        most of the time, it *can* run out if it is given a pattern that contains a
1156        runaway infinite recursion. I updated the discussion in the pcrestack man
1157        page.
1158    
1159    13. Now that we have gone to the x.xx style of version numbers, the minor
1160        version may start with zero. Using 08 or 09 is a bad idea because users
1161        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1162        interpreted as invalid octal numbers. I've updated the previous comment in
1163        configure.ac, and also added a check that gives an error if 08 or 09 are
1164        used.
1165    
1166    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1167        causing partial matching to fail when the end of the subject matched \W
1168        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1169    
1170    15. There were some discrepancies between the declarations in pcre_internal.h
1171        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1172        their definitions. The declarations used "const uschar *" and the
1173        definitions used USPTR. Even though USPTR is normally defined as "const
1174        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1175        reported that: "This difference in casting confuses some C++ compilers, for
1176        example, SunCC recognizes above declarations as different functions and
1177        generates broken code for hbpcre." I have changed the declarations to use
1178        USPTR.
1179    
1180    16. GNU libtool is named differently on some systems. The autogen.sh script now
1181        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1182        (FreeBSD).
1183    
1184    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1185        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1186        comment: "Figure out how to create a longlong from a string: strtoll and
1187        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1188        instance, but it only takes 2 args instead of 3!"
1189    
1190    18. A subtle bug concerned with back references has been fixed by a change of
1191        specification, with a corresponding code fix. A pattern such as
1192        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1193        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1194        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1195        same bug. Such groups have to be quantified to be useful, or contained
1196        inside another quantified group. (If there's no repetition, the reference
1197        can never match.) The problem arises because, having left the group and
1198        moved on to the rest of the pattern, a later failure that backtracks into
1199        the group uses the captured value from the final iteration of the group
1200        rather than the correct earlier one. I have fixed this in PCRE by forcing
1201        any group that contains a reference to itself to be an atomic group; that
1202        is, there cannot be any backtracking into it once it has completed. This is
1203        similar to recursive and subroutine calls.
1204    
1205    
1206    Version 8.00 19-Oct-09
1207  ----------------------  ----------------------
1208    
1209  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
1210      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
1211      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
1212      error.      error.
1213    
1214  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,
1215      "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
1216      in a Windows environment.      in a Windows environment.
1217    
1218  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
1219      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
1220      --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
1221      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
1222      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
1223      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
1224      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
1225    
1226  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
1227      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
1228      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
1229      the old behaviour.      the old behaviour.
1230    
1231  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
1232      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
1233      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
1234      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
1235    
1236  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
1237      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1238    
1239  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
1240      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
1241      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
1242      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
1243      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
1244      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
1245    
1246  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
1247      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
1248      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1249      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1250      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
1251      result.      result.
1252    
1253  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
1254      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
1255      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
1256      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
1257      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
1258      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
1259    
1260  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
1261      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
1262      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,
1263      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
1264      pcre_exec().  
1265    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1266  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
1267      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
1268      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
1269      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
1270      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
1271      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
1272      final character ended with (*FAIL).  
   
1273  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
1274      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
1275      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
1276      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
1277      "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
1278      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
1279    
1280  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
1281      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
1282      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
1283      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
1284      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
1285      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
1286    
1287  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1288      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
1289      PCRE has not been installed from source.      PCRE has not been installed from source.
1290    
1291  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1292      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1293      library.      library.
1294    
1295  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1296      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1297      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
1298      these options useful.      these options useful.
1299    
1300  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
1301      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
1302      nmatch is forced to zero.      nmatch is forced to zero.
1303    
1304  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
1305      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
1306      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
1307    
1308  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
1309      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
1310      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
1311      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
1312      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1313      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
1314      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
1315      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
1316    
1317  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1318      /g option in pcretest when the pattern contains \K, which makes it possible      /g option in pcretest when the pattern contains \K, which makes it possible
1319      to have an empty string match not at the start, even when the pattern is      to have an empty string match not at the start, even when the pattern is
1320      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
1321    
1322  21. If the maximum number of capturing subpatterns in a recursion was greater  21. If the maximum number of capturing subpatterns in a recursion was greater
1323      than the maximum at the outer level, the higher number was returned, but      than the maximum at the outer level, the higher number was returned, but
1324      with unset values at the outer level. The correct (outer level) value is      with unset values at the outer level. The correct (outer level) value is
1325      now given.      now given.
1326    
1327  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1328      PCRE did not set those parentheses (unlike Perl). I have now found a way to      PCRE did not set those parentheses (unlike Perl). I have now found a way to
1329      make it do so. The string so far is captured, making this feature      make it do so. The string so far is captured, making this feature
1330      compatible with Perl.      compatible with Perl.
1331    
1332    23. The tests have been re-organized, adding tests 11 and 12, to make it
1333        possible to check the Perl 5.10 features against Perl 5.10.
1334    
1335    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1336        pattern matches a fixed length string. PCRE did not allow this; now it
1337        does. Neither allows recursion.
1338    
1339    25. I finally figured out how to implement a request to provide the minimum
1340        length of subject string that was needed in order to match a given pattern.
1341        (It was back references and recursion that I had previously got hung up
1342        on.) This code has now been added to pcre_study(); it finds a lower bound
1343        to the length of subject needed. It is not necessarily the greatest lower
1344        bound, but using it to avoid searching strings that are too short does give
1345        some useful speed-ups. The value is available to calling programs via
1346        pcre_fullinfo().
1347    
1348    26. While implementing 25, I discovered to my embarrassment that pcretest had
1349        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1350        study optimizations had never been tested with that matching function.
1351        Oops. What is worse, even when it was passed study data, there was a bug in
1352        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1353        were also very few tests of studied patterns with pcre_dfa_exec().
1354    
1355    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1356        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1357        on the other side of the coin, they are no longer allowed to have different
1358        names, because these cannot be distinguished in PCRE, and this has caused
1359        confusion. (This is a difference from Perl.)
1360    
1361    28. When duplicate subpattern names are present (necessarily with different
1362        numbers, as required by 27 above), and a test is made by name in a
1363        conditional pattern, either for a subpattern having been matched, or for
1364        recursion in such a pattern, all the associated numbered subpatterns are
1365        tested, and the overall condition is true if the condition is true for any
1366        one of them. This is the way Perl works, and is also more like the way
1367        testing by number works.
1368    
1369    
1370  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1371  ---------------------  ---------------------

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