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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.10 03-Jun-2010  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    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
60    
61    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
62        structure could go wrong in environments where size_t is not the same size
63        as int.
64    
65    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
66        set.
67    
68    15. The EBCDIC support had decayed; later updates to the code had included
69        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
70        general tidy up of EBCDIC-related issues, and the documentation was also
71        not quite right. There is now a test that can be run on ASCII systems to
72        check some of the EBCDIC-related things (but is it not a full test).
73    
74    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
75        in a small tidy to the code.
76    
77    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
78    
79    18. If the --only-matching (-o) option in pcregrep is specified multiple
80        times, each one causes appropriate output. For example, -o1 -o2 outputs the
81        substrings matched by the 1st and 2nd capturing parentheses. A separating
82        string can be specified by --om-separator (default empty).
83    
84    19. Improving the first n character searches.
85    
86    
87    Version 8.31 06-July-2012
88    -------------------------
89    
90    1.  Fixing a wrong JIT test case and some compiler warnings.
91    
92    2.  Removed a bashism from the RunTest script.
93    
94    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
95        to unsigned type, result still unsigned" that was given by an MS compiler
96        on encountering the code "-sizeof(xxx)".
97    
98    4.  Partial matching support is added to the JIT compiler.
99    
100    5.  Fixed several bugs concerned with partial matching of items that consist
101        of more than one character:
102    
103        (a) /^(..)\1/ did not partially match "aba" because checking references was
104            done on an "all or nothing" basis. This also applied to repeated
105            references.
106    
107        (b) \R did not give a hard partial match if \r was found at the end of the
108            subject.
109    
110        (c) \X did not give a hard partial match after matching one or more
111            characters at the end of the subject.
112    
113        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
114            a partial match for the string "\r".
115    
116        (e) When newline was set to CRLF, the metacharacter "." did not recognize
117            a partial match for a CR character at the end of the subject string.
118    
119    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
120        running pcretest, the text "(JIT)" added to the output whenever JIT is
121        actually used to run the match.
122    
123    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
124        or /S+[+] with a digit between 1 and 7.
125    
126    8.  OP_NOT now supports any UTF character not just single-byte ones.
127    
128    9.  (*MARK) control verb is now supported by the JIT compiler.
129    
130    10. The command "./RunTest list" lists the available tests without actually
131        running any of them. (Because I keep forgetting what they all are.)
132    
133    11. Add PCRE_INFO_MAXLOOKBEHIND.
134    
135    12. Applied a (slightly modified) user-supplied patch that improves performance
136        when the heap is used for recursion (compiled with --disable-stack-for-
137        recursion). Instead of malloc and free for each heap frame each time a
138        logical recursion happens, frames are retained on a chain and re-used where
139        possible. This sometimes gives as much as 30% improvement.
140    
141    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
142        call.
143    
144    14. As documented, (*COMMIT) is now confined to within a positive assertion.
145    
146    15. It is now possible to link pcretest with libedit as an alternative to
147        libreadline.
148    
149    16. (*COMMIT) control verb is now supported by the JIT compiler.
150    
151    17. The Unicode data tables have been updated to Unicode 6.1.0.
152    
153    18. Added --file-list option to pcregrep.
154    
155    19. Added binary file support to pcregrep, including the -a, --binary-files,
156        -I, and --text options.
157    
158    20. The madvise function is renamed for posix_madvise for QNX compatibility
159        reasons. Fixed by Giuseppe D'Angelo.
160    
161    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
162    
163    22. Changed the option for creating symbolic links for 16-bit man pages from
164        -s to -sf so that re-installing does not cause issues.
165    
166    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
167    
168    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
169        matches in certain environments (the workspace was not being correctly
170        retained). Also added to pcre_dfa_exec() a simple plausibility check on
171        some of the workspace data at the beginning of a restart.
172    
173    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
174        was not doing so when it should - probably a typo introduced by SVN 528
175        (change 8.10/14).
176    
177    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
178        \w+ when the character tables indicated that \x{c4} was a word character.
179        There were several related cases, all because the tests for doing a table
180        lookup were testing for characters less than 127 instead of 255.
181    
182    27. If a pattern contains capturing parentheses that are not used in a match,
183        their slots in the ovector are set to -1. For those that are higher than
184        any matched groups, this happens at the end of processing. In the case when
185        there were back references that the ovector was too small to contain
186        (causing temporary malloc'd memory to be used during matching), and the
187        highest capturing number was not used, memory off the end of the ovector
188        was incorrectly being set to -1. (It was using the size of the temporary
189        memory instead of the true size.)
190    
191    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
192        ovector size, it uses memory at the end of the block that it has got.
193    
194    29. Check for an overlong MARK name and give an error at compile time. The
195        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
196    
197    30. JIT compiler update.
198    
199    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
200        Rill for the patch.
201    
202    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
203    
204    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
205    
206    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
207        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
208        was enabled.
209    
210    35. Improve JIT code generation for greedy plus quantifier.
211    
212    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
213        1 to "aa" instead of to an empty string. The bug affected repeated groups
214        that could potentially match an empty string.
215    
216    37. Optimizing single character iterators in JIT.
217    
218    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
219        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
220        codepoints that are too big for the mode are faulted, and in a UTF mode,
221        disallowed codepoints are also faulted.
222    
223    39. If PCRE was compiled with UTF support, in three places in the DFA
224        matcher there was code that should only have been obeyed in UTF mode, but
225        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
226        processing when bytes with values greater than 127 were present. In 16-bit
227        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
228        both cases the values are those that cannot be the first data item in a UTF
229        character. The three items that might have provoked this were recursions,
230        possessively repeated groups, and atomic groups.
231    
232    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
233        and pcregrep, because some OS require shared objects to be explicitly
234        passed to ld, causing the link step to fail if they are not.
235    
236    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
237        mode, patterns that started with \h* or \R* might be incorrectly matched.
238    
239    
240    Version 8.30 04-February-2012
241    -----------------------------
242    
243    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
244        name is defined in ctype.h.
245    
246    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
247        only in quite long subpatterns.
248    
249    3.  Removed the function pcre_info(), which has been obsolete and deprecated
250        since it was replaced by pcre_fullinfo() in February 2000.
251    
252    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
253        match a (*MARK), and the match failed at the start of the subject, a
254        reference to memory before the start of the subject could occur. This bug
255        was introduced by fix 17 of release 8.21.
256    
257    5.  A reference to an unset group with zero minimum repetition was giving
258        totally wrong answers (in non-JavaScript-compatibility mode). For example,
259        /(another)?(\1?)test/ matched against "hello world test". This bug was
260        introduced in release 8.13.
261    
262    6.  Add support for 16-bit character strings (a large amount of work involving
263        many changes and refactorings).
264    
265    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
266        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
267        from a file.
268    
269    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
270        rounding is not applied in this particular case).
271    
272    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
273        if they appear, or are escaped, in patterns.
274    
275    10. Get rid of a number of -Wunused-but-set-variable warnings.
276    
277    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
278        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
279        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
280        also returns the mark "x". This bug applied to capturing parentheses,
281        non-capturing parentheses, and atomic parentheses. It also applied to some
282        assertions.
283    
284    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
285        information out of configure.ac instead of relying on pcre.h.generic, which
286        is not stored in the repository.
287    
288    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
289        -lreadline.
290    
291    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
292    
293    15. Applied Graycode's patch to put the top-level frame on the stack rather
294        than the heap when not using the stack for recursion. This gives a
295        performance improvement in many cases when recursion is not deep.
296    
297    16. Experimental code added to "pcretest -C" to output the stack frame size.
298    
299    
300    Version 8.21 12-Dec-2011
301    ------------------------
302    
303    1.  Updating the JIT compiler.
304    
305    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
306        are added as well.
307    
308    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
309        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
310        calling _pcre_jit_exec. Some extra comments are added.
311    
312    4.  (*MARK) settings inside atomic groups that do not contain any capturing
313        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
314        was introduced by change 18 for 8.20.
315    
316    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
317        ECMA-262 standard.
318    
319    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
320        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
321        This bug was probably introduced by change 9 of 8.13.
322    
323    7.  While fixing 6 above, I noticed that a number of other items were being
324        incorrectly rejected as "not fixed length". This arose partly because newer
325        opcodes had not been added to the fixed-length checking code. I have (a)
326        corrected the bug and added tests for these items, and (b) arranged for an
327        error to occur if an unknown opcode is encountered while checking for fixed
328        length instead of just assuming "not fixed length". The items that were
329        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
330        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
331        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
332    
333    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
334        being incorrectly compiled and would have given unpredicatble results.
335    
336    9.  A possessively repeated subpattern with minimum repeat count greater than
337        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
338        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
339        the first (A) could occur when it should not.
340    
341    10. Add a cast and remove a redundant test from the code.
342    
343    11. JIT should use pcre_malloc/pcre_free for allocation.
344    
345    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
346        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
347        is anything other than /usr, -L is still shown).
348    
349    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
350    
351    14. Perl does not support \N without a following name in a [] class; PCRE now
352        also gives an error.
353    
354    15. If a forward reference was repeated with an upper limit of around 2000,
355        it caused the error "internal error: overran compiling workspace". The
356        maximum number of forward references (including repeats) was limited by the
357        internal workspace, and dependent on the LINK_SIZE. The code has been
358        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
359        the default depends on LINK_SIZE. There is a new upper limit (for safety)
360        of around 200,000 forward references. While doing this, I also speeded up
361        the filling in of repeated forward references.
362    
363    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
364        incorrectly expecting the subject to contain another "a" after the start.
365    
366    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
367        in the match, the SKIP should be ignored. This was not happening; instead
368        the SKIP was being treated as NOMATCH. For patterns such as
369        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
370        tested.
371    
372    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
373        now much more compatible with Perl, in particular in cases where the result
374        is a non-match for a non-anchored pattern. For example, if
375        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
376        "m", where previously it did not return a name. A side effect of this
377        change is that for partial matches, the last encountered mark name is
378        returned, as for non matches. A number of tests that were previously not
379        Perl-compatible have been moved into the Perl-compatible test files. The
380        refactoring has had the pleasing side effect of removing one argument from
381        the match() function, thus reducing its stack requirements.
382    
383    19. If the /S+ option was used in pcretest to study a pattern using JIT,
384        subsequent uses of /S (without +) incorrectly behaved like /S+.
385    
386    21. Retrieve executable code size support for the JIT compiler and fixing
387        some warnings.
388    
389    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
390        not work when the shorter character appeared right at the end of the
391        subject string.
392    
393    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
394        systems.
395    
396    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
397        output it when the /M option is used in pcretest.
398    
399    25. The CheckMan script was not being included in the distribution. Also, added
400        an explicit "perl" to run Perl scripts from the PrepareRelease script
401        because this is reportedly needed in Windows.
402    
403    26. If study data was being save in a file and studying had not found a set of
404        "starts with" bytes for the pattern, the data written to the file (though
405        never used) was taken from uninitialized memory and so caused valgrind to
406        complain.
407    
408    27. Updated RunTest.bat as provided by Sheri Pierce.
409    
410    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
411    
412    29. Computation of memory usage for the table of capturing group names was
413        giving an unnecessarily large value.
414    
415    
416    Version 8.20 21-Oct-2011
417    ------------------------
418    
419    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
420        a POSIX class. After further experiments with Perl, which convinced me that
421        Perl has bugs and confusions, a closing square bracket is no longer allowed
422        in a POSIX name. This bug also affected patterns with classes that started
423        with full stops.
424    
425    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
426        captured substring, but while checking the failing first alternative,
427        substring 1 is temporarily captured. If the output vector supplied to
428        pcre_exec() was not big enough for this capture, the yield of the function
429        was still zero ("insufficient space for captured substrings"). This cannot
430        be totally fixed without adding another stack variable, which seems a lot
431        of expense for a edge case. However, I have improved the situation in cases
432        such as /(a)(b)x|abc/ matched against "abc", where the return code
433        indicates that fewer than the maximum number of slots in the ovector have
434        been set.
435    
436    3.  Related to (2) above: when there are more back references in a pattern than
437        slots in the output vector, pcre_exec() uses temporary memory during
438        matching, and copies in the captures as far as possible afterwards. It was
439        using the entire output vector, but this conflicts with the specification
440        that only 2/3 is used for passing back captured substrings. Now it uses
441        only the first 2/3, for compatibility. This is, of course, another edge
442        case.
443    
444    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
445        main code base, and can be used by building with --enable-jit. When this is
446        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
447        runtime --no-jit option is given.
448    
449    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
450        ovector, the return from the function was zero, implying that there were
451        other matches that did not fit. The correct "exactly full" value is now
452        returned.
453    
454    6.  If a subpattern that was called recursively or as a subroutine contained
455        (*PRUNE) or any other control that caused it to give a non-standard return,
456        invalid errors such as "Error -26 (nested recursion at the same subject
457        position)" or even infinite loops could occur.
458    
459    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
460        computing the minimum length on reaching *ACCEPT, and so ended up with the
461        wrong value of 1 rather than 0. Further investigation indicates that
462        computing a minimum subject length in the presence of *ACCEPT is difficult
463        (think back references, subroutine calls), and so I have changed the code
464        so that no minimum is registered for a pattern that contains *ACCEPT.
465    
466    8.  If (*THEN) was present in the first (true) branch of a conditional group,
467        it was not handled as intended. [But see 16 below.]
468    
469    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
470        Sheri Pierce.
471    
472    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
473        the first byte in a match must be "a".
474    
475    11. Change 17 for 8.13 increased the recursion depth for patterns like
476        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
477        pattern contains any instances of (*THEN). If it does not, the old
478        optimizations are restored. It would be nice to do this on a per-group
479        basis, but at the moment that is not feasible.
480    
481    12. In some environments, the output of pcretest -C is CRLF terminated. This
482        broke RunTest's code that checks for the link size. A single white space
483        character after the value is now allowed for.
484    
485    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
486        For "fr", it uses the Windows-specific input and output files.
487    
488    14. If (*THEN) appeared in a group that was called recursively or as a
489        subroutine, it did not work as intended. [But see next item.]
490    
491    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
492        pattern fragments (but not containing any | characters). If A and B are
493        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
494        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
495        D. In other words, Perl considers parentheses that do not contain any |
496        characters to be part of a surrounding alternative, whereas PCRE was
497        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
498        differently. PCRE now behaves in the same way as Perl, except in the case
499        of subroutine/recursion calls such as (?1) which have in any case always
500        been different (but PCRE had them first :-).
501    
502    16. Related to 15 above: Perl does not treat the | in a conditional group as
503        creating alternatives. Such a group is treated in the same way as an
504        ordinary group without any | characters when processing (*THEN). PCRE has
505        been changed to match Perl's behaviour.
506    
507    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
508        RunGrepTest script failed.
509    
510    18. Change 22 for version 13 caused atomic groups to use more stack. This is
511        inevitable for groups that contain captures, but it can lead to a lot of
512        stack use in large patterns. The old behaviour has been restored for atomic
513        groups that do not contain any capturing parentheses.
514    
515    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
516        suppress the check for a minimum subject length at run time. (If it was
517        given to pcre_exec() or pcre_dfa_exec() it did work.)
518    
519    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
520        fail to work when decoding hex characters in data strings in EBCDIC
521        environments.
522    
523    21. It appears that in at least one Mac OS environment, the isxdigit() function
524        is implemented as a macro that evaluates to its argument more than once,
525        contravening the C 90 Standard (I haven't checked a later standard). There
526        was an instance in pcretest which caused it to go wrong when processing
527        \x{...} escapes in subject strings. The has been rewritten to avoid using
528        things like p++ in the argument of isxdigit().
529    
530    
531    Version 8.13 16-Aug-2011
532    ------------------------
533    
534    1.  The Unicode data tables have been updated to Unicode 6.0.0.
535    
536    2.  Two minor typos in pcre_internal.h have been fixed.
537    
538    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
539        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
540        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
541    
542    4.  There were a number of related bugs in the code for matching backrefences
543        caselessly in UTF-8 mode when codes for the characters concerned were
544        different numbers of bytes. For example, U+023A and U+2C65 are an upper
545        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
546        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
547        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
548        2-byte code at the end of the subject (it thought there wasn't enough data
549        left).
550    
551    5.  Comprehensive information about what went wrong is now returned by
552        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
553        as the output vector has at least 2 elements. The offset of the start of
554        the failing character and a reason code are placed in the vector.
555    
556    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
557        now returned is for the first byte of the failing character, instead of the
558        last byte inspected. This is an incompatible change, but I hope it is small
559        enough not to be a problem. It makes the returned offset consistent with
560        pcre_exec() and pcre_dfa_exec().
561    
562    7.  pcretest now gives a text phrase as well as the error number when
563        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
564        failure, the offset and reason code are output.
565    
566    8.  When \R was used with a maximizing quantifier it failed to skip backwards
567        over a \r\n pair if the subsequent match failed. Instead, it just skipped
568        back over a single character (\n). This seems wrong (because it treated the
569        two characters as a single entity when going forwards), conflicts with the
570        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
571        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
572        has been changed.
573    
574    9.  Some internal refactoring has changed the processing so that the handling
575        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
576        time (the PCRE_DOTALL option was changed this way some time ago: version
577        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
578        which was always a bit of a fudge. It also means that there is one less
579        argument for the match() function, which reduces its stack requirements
580        slightly. This change also fixes an incompatibility with Perl: the pattern
581        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
582    
583    10. More internal refactoring has drastically reduced the number of recursive
584        calls to match() for possessively repeated groups such as (abc)++ when
585        using pcre_exec().
586    
587    11. While implementing 10, a number of bugs in the handling of groups were
588        discovered and fixed:
589    
590        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
591        (a|)*(?1) gave a compile-time internal error.
592        ((a|)+)+  did not notice that the outer group could match an empty string.
593        (^a|^)+   was not marked as anchored.
594        (.*a|.*)+ was not marked as matching at start or after a newline.
595    
596    12. Yet more internal refactoring has removed another argument from the match()
597        function. Special calls to this function are now indicated by setting a
598        value in a variable in the "match data" data block.
599    
600    13. Be more explicit in pcre_study() instead of relying on "default" for
601        opcodes that mean there is no starting character; this means that when new
602        ones are added and accidentally left out of pcre_study(), testing should
603        pick them up.
604    
605    14. The -s option of pcretest has been documented for ages as being an old
606        synonym of -m (show memory usage). I have changed it to mean "force study
607        for every regex", that is, assume /S for every regex. This is similar to -i
608        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
609        using it. It makes it easier to run collections of tests with and without
610        study enabled, and thereby test pcre_study() more easily. All the standard
611        tests are now run with and without -s (but some patterns can be marked as
612        "never study" - see 20 below).
613    
614    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
615        restoration of the capturing data to the outer values was not happening
616        correctly.
617    
618    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
619        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
620        pattern had matched an empty string, and so incorrectly returned a no
621        match.
622    
623    17. There was optimizing code for the last branch of non-capturing parentheses,
624        and also for the obeyed branch of a conditional subexpression, which used
625        tail recursion to cut down on stack usage. Unfortunately, now that there is
626        the possibility of (*THEN) occurring in these branches, tail recursion is
627        no longer possible because the return has to be checked for (*THEN). These
628        two optimizations have therefore been removed. [But see 8.20/11 above.]
629    
630    18. If a pattern containing \R was studied, it was assumed that \R always
631        matched two bytes, thus causing the minimum subject length to be
632        incorrectly computed because \R can also match just one byte.
633    
634    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
635        was incorrectly computed.
636    
637    20. If /S is present twice on a test pattern in pcretest input, it now
638        *disables* studying, thereby overriding the use of -s on the command line
639        (see 14 above). This is necessary for one or two tests to keep the output
640        identical in both cases.
641    
642    21. When (*ACCEPT) was used in an assertion that matched an empty string and
643        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
644    
645    22. When an atomic group that contained a capturing parenthesis was
646        successfully matched, but the branch in which it appeared failed, the
647        capturing was not being forgotten if a higher numbered group was later
648        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
649        group 1 to "a", when in fact it should be unset. This applied to multi-
650        branched capturing and non-capturing groups, repeated or not, and also to
651        positive assertions (capturing in negative assertions does not happen
652        in PCRE) and also to nested atomic groups.
653    
654    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
655        subject after a captured substring, to make it easier to tell which of a
656        number of identical substrings has been captured.
657    
658    24. The way atomic groups are processed by pcre_exec() has been changed so that
659        if they are repeated, backtracking one repetition now resets captured
660        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
661        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
662        "aaa". Previously, it would have been "a". As part of this code
663        refactoring, the way recursive calls are handled has also been changed.
664    
665    25. If an assertion condition captured any substrings, they were not passed
666        back unless some other capturing happened later. For example, if
667        (?(?=(a))a) was matched against "a", no capturing was returned.
668    
669    26. When studying a pattern that contained subroutine calls or assertions,
670        the code for finding the minimum length of a possible match was handling
671        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
672        group 1 called group 2 while simultaneously a separate group 2 called group
673        1). A stack overflow occurred in this case. I have fixed this by limiting
674        the recursion depth to 10.
675    
676    27. Updated RunTest.bat in the distribution to the version supplied by Tom
677        Fortmann. This supports explicit test numbers on the command line, and has
678        argument validation and error reporting.
679    
680    28. An instance of \X with an unlimited repeat could fail if at any point the
681        first character it looked at was a mark character.
682    
683    29. Some minor code refactoring concerning Unicode properties and scripts
684        should reduce the stack requirement of match() slightly.
685    
686    30. Added the '=' option to pcretest to check the setting of unused capturing
687        slots at the end of the pattern, which are documented as being -1, but are
688        not included in the return count.
689    
690    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
691        compiled something random. Now it gives a compile-time error (as does
692        Perl).
693    
694    32. A *MARK encountered during the processing of a positive assertion is now
695        recorded and passed back (compatible with Perl).
696    
697    33. If --only-matching or --colour was set on a pcregrep call whose pattern
698        had alternative anchored branches, the search for a second match in a line
699        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
700        matched the line "0102" twice. The same bug affected patterns that started
701        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
702        twice.
703    
704    34. Previously, PCRE did not allow quantification of assertions. However, Perl
705        does, and because of capturing effects, quantifying parenthesized
706        assertions may at times be useful. Quantifiers are now allowed for
707        parenthesized assertions.
708    
709    35. A minor code tidy in pcre_compile() when checking options for \R usage.
710    
711    36. \g was being checked for fancy things in a character class, when it should
712        just be a literal "g".
713    
714    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
715        appearance of a nested POSIX class supersedes an apparent external class.
716        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
717        unescaped square brackets may also appear as part of class names. For
718        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
719        more like Perl. (But see 8.20/1 above.)
720    
721    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
722        was because it thought it was \N{name}, which is not supported).
723    
724    39. Add minix to OS list not supporting the -S option in pcretest.
725    
726    40. PCRE tries to detect cases of infinite recursion at compile time, but it
727        cannot analyze patterns in sufficient detail to catch mutual recursions
728        such as ((?1))((?2)). There is now a runtime test that gives an error if a
729        subgroup is called recursively as a subpattern for a second time at the
730        same position in the subject string. In previous releases this might have
731        been caught by the recursion limit, or it might have run out of stack.
732    
733    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
734        happen only once. PCRE was, however incorrectly giving a compile time error
735        "recursive call could loop indefinitely" because it cannot analyze the
736        pattern in sufficient detail. The compile time test no longer happens when
737        PCRE is compiling a conditional subpattern, but actual runaway loops are
738        now caught at runtime (see 40 above).
739    
740    42. It seems that Perl allows any characters other than a closing parenthesis
741        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
742        has been changed to be the same.
743    
744    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
745        as not to get warnings when autogen.sh is called. Also changed
746        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
747    
748    44. To help people who use pcregrep to scan files containing exceedingly long
749        lines, the following changes have been made:
750    
751        (a) The default value of the buffer size parameter has been increased from
752            8K to 20K. (The actual buffer used is three times this size.)
753    
754        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
755            PCRE is built.
756    
757        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
758            to be set at run time.
759    
760        (d) Numerical values in pcregrep options can be followed by K or M, for
761            example --buffer-size=50K.
762    
763        (e) If a line being scanned overflows pcregrep's buffer, an error is now
764            given and the return code is set to 2.
765    
766    45. Add a pointer to the latest mark to the callout data block.
767    
768    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
769        partial match of an empty string instead of no match. This was specific to
770        the use of ".".
771    
772    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
773        complete match instead of a partial match. This bug was dependent on both
774        the PCRE_UTF8 and PCRE_DOTALL options being set.
775    
776    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
777        starting byte set, because \b was not being ignored.
778    
779    
780    Version 8.12 15-Jan-2011
781    ------------------------
782    
783    1.  Fixed some typos in the markup of the man pages, and wrote a script that
784        checks for such things as part of the documentation building process.
785    
786    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
787        --match-limit and --recursion-limit options (added for 8.11). In
788        particular, this made one of the standard tests fail. (The integer value
789        went into the wrong half of a long int.)
790    
791    3.  If the --colour option was given to pcregrep with -v (invert match), it
792        did strange things, either producing crazy output, or crashing. It should,
793        of course, ignore a request for colour when reporting lines that do not
794        match.
795    
796    4.  Another pcregrep bug caused similar problems if --colour was specified with
797        -M (multiline) and the pattern match finished with a line ending.
798    
799    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
800        matched in multiline mode, the following line was shown as part of the
801        match. This seems wrong, so I have changed it.
802    
803    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
804        the check for further matches in the same line (so they could be coloured)
805        to overrun the end of the current line. If another match was found, it was
806        incorrectly shown (and then shown again when found in the next line).
807    
808    7.  If pcregrep was compiled under Windows, there was a reference to the
809        function pcregrep_exit() before it was defined. I am assuming this was
810        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
811        reported by a user. I've moved the definition above the reference.
812    
813    
814    Version 8.11 10-Dec-2010
815    ------------------------
816    
817    1.  (*THEN) was not working properly if there were untried alternatives prior
818        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
819        backtracked to try for "b" instead of moving to the next alternative branch
820        at the same level (in this case, to look for "c"). The Perl documentation
821        is clear that when (*THEN) is backtracked onto, it goes to the "next
822        alternative in the innermost enclosing group".
823    
824    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
825        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
826        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
827        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
828        (*THEN).
829    
830    3.  If \s appeared in a character class, it removed the VT character from
831        the class, even if it had been included by some previous item, for example
832        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
833        of \s, but is part of the POSIX "space" class.)
834    
835    4.  A partial match never returns an empty string (because you can always
836        match an empty string at the end of the subject); however the checking for
837        an empty string was starting at the "start of match" point. This has been
838        changed to the "earliest inspected character" point, because the returned
839        data for a partial match starts at this character. This means that, for
840        example, /(?<=abc)def/ gives a partial match for the subject "abc"
841        (previously it gave "no match").
842    
843    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
844        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
845        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
846        has an implication that the given string is incomplete (because a partial
847        match is preferred over a full match). For this reason, these items now
848        give a partial match in this situation. [Aside: previously, the one case
849        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
850        match rather than a full match, which was wrong by the old rules, but is
851        now correct.]
852    
853    6.  There was a bug in the handling of #-introduced comments, recognized when
854        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
855        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
856        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
857        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
858        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
859        places in pcre_compile().
860    
861    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
862        comments when looking ahead for named forward references to subpatterns,
863        the only newline sequence it recognized was NL. It now handles newlines
864        according to the set newline convention.
865    
866    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
867        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
868        cater for a lack of strerror(). These oversights have been fixed.
869    
870    9.  Added --match-limit and --recursion-limit to pcregrep.
871    
872    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
873    
874    11. When the -o option was used, pcregrep was setting a return code of 1, even
875        when matches were found, and --line-buffered was not being honoured.
876    
877    12. Added an optional parentheses number to the -o and --only-matching options
878        of pcregrep.
879    
880    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
881        can match an empty string. The code to do it in pcretest and pcredemo
882        needed fixing:
883    
884        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
885            only one byte after an empty string match just before CRLF (this case
886            just got forgotten; "any" and "anycrlf" were OK).
887    
888        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
889            mode when an empty string match preceded an ASCII character followed by
890            a non-ASCII character. (The code for advancing by one character rather
891            than one byte was nonsense.)
892    
893        (c) The pcredemo.c sample program did not have any code at all to handle
894            the cases when CRLF is a valid newline sequence.
895    
896    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
897        as a starting offset was within the subject string. There is now a new
898        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
899        negative or greater than the length of the string. In order to test this,
900        pcretest is extended to allow the setting of negative starting offsets.
901    
902    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
903        starting offset points to the beginning of a UTF-8 character was
904        unnecessarily clumsy. I tidied it up.
905    
906    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
907        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
908    
909    17. Nobody had reported that the --include_dir option, which was added in
910        release 7.7 should have been called --include-dir (hyphen, not underscore)
911        for compatibility with GNU grep. I have changed it to --include-dir, but
912        left --include_dir as an undocumented synonym, and the same for
913        --exclude-dir, though that is not available in GNU grep, at least as of
914        release 2.5.4.
915    
916    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
917        characters from a string of bytes) have been redefined so as not to use
918        loops, in order to improve performance in some environments. At the same
919        time, I abstracted some of the common code into auxiliary macros to save
920        repetition (this should not affect the compiled code).
921    
922    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
923        compile-time error is now given if \c is not followed by an ASCII
924        character, that is, a byte less than 128. (In EBCDIC mode, the code is
925        different, and any byte value is allowed.)
926    
927    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
928        START_OPTIMIZE option, which is now allowed at compile time - but just
929        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
930        to pcregrep and other applications that have no direct access to PCRE
931        options. The new /Y option in pcretest sets this option when calling
932        pcre_compile().
933    
934    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
935        back references. Groups containing recursive back references were forced to
936        be atomic by that change, but in the case of named groups, the amount of
937        memory required was incorrectly computed, leading to "Failed: internal
938        error: code overflow". This has been fixed.
939    
940    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
941        pcretest.c, to avoid build problems in some Borland environments.
942    
943    
944    Version 8.10 25-Jun-2010
945  ------------------------  ------------------------
946    
947  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 42  Version 8.10 03-Jun-2010 Line 982  Version 8.10 03-Jun-2010
982  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
983      studied, and the match started with a letter with a code point greater than      studied, and the match started with a letter with a code point greater than
984      127 whose first byte was different to the first byte of the other case of      127 whose first byte was different to the first byte of the other case of
985      the letter, the other case of this starting letter was not recognized      the letter, the other case of this starting letter was not recognized
986      (#976).      (#976).
987    
988  12. If a pattern that was studied started with a repeated Unicode property  12. If a pattern that was studied started with a repeated Unicode property
# Line 68  Version 8.10 03-Jun-2010 Line 1008  Version 8.10 03-Jun-2010
1008    
1009  17. Added a check for running out of memory when PCRE is compiled with  17. Added a check for running out of memory when PCRE is compiled with
1010      --disable-stack-for-recursion (#990).      --disable-stack-for-recursion (#990).
1011    
1012  18. If the last data line in a file for pcretest does not have a newline on  18. If the last data line in a file for pcretest does not have a newline on
1013      the end, a newline was missing in the output.      the end, a newline was missing in the output.
1014    
1015  19. The default pcre_chartables.c file recognizes only ASCII characters (values  19. The default pcre_chartables.c file recognizes only ASCII characters (values
1016      less than 128) in its various bitmaps. However, there is a facility for      less than 128) in its various bitmaps. However, there is a facility for
1017      generating tables according to the current locale when PCRE is compiled. It      generating tables according to the current locale when PCRE is compiled. It
1018      turns out that in some environments, 0x85 and 0xa0, which are Unicode space      turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1019      characters, are recognized by isspace() and therefore were getting set in      characters, are recognized by isspace() and therefore were getting set in
1020      these tables. This caused a problem in UTF-8 mode when pcre_study() was      these tables, and indeed these tables seem to approximate to ISO 8859. This
1021      used to create a list of bytes that can start a match. For \s, it was      caused a problem in UTF-8 mode when pcre_study() was used to create a list
1022      including 0x85 and 0xa0, which of course cannot start UTF-8 characters. I      of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1023      have changed the code so that only real ASCII characters (less than 128)      which of course cannot start UTF-8 characters. I have changed the code so
1024      and the correct starting bytes for UTF-8 encodings are set in this case.      that only real ASCII characters (less than 128) and the correct starting
1025      (When PCRE_UCP is set - see 9 above - the code is different altogether.)      bytes for UTF-8 encodings are set for characters greater than 127 when in
1026        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1027        altogether.)
1028    
1029    20. Added the /T option to pcretest so as to be able to run tests with non-
1030        standard character tables, thus making it possible to include the tests
1031        used for 19 above in the standard set of tests.
1032    
1033    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1034        reference to a subpattern the other side of a comment that contains an
1035        opening parenthesis caused either an internal compiling error, or a
1036        reference to the wrong subpattern.
1037    
1038    
1039  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010

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