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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 10-Mar-2010  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
67    
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    18. Added --file-list option to pcregrep.
71    
72    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
74    
75    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
77    
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
79    
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
82    
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
84    
85    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
86        matches in certain environments (the workspace was not being correctly
87        retained). Also added to pcre_dfa_exec() a simple plausibility check on
88        some of the workspace data at the beginning of a restart.
89    
90    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
91        was not doing so when it should - probably a typo introduced by SVN 528
92        (change 8.10/14).
93    
94    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
95        \w+ when the character tables indicated that \x{c4} was a word character.
96        There were several related cases, all because the tests for doing a table
97        lookup were testing for characters less than 127 instead of 255.
98    
99    27. If a pattern contains capturing parentheses that are not used in a match,
100        their slots in the ovector are set to -1. For those that are higher than
101        any matched groups, this happens at the end of processing. In the case when
102        there were back references that the ovector was too small to contain
103        (causing temporary malloc'd memory to be used during matching), and the
104        highest capturing number was not used, memory off the end of the ovector
105        was incorrectly being set to -1. (It was using the size of the temporary
106        memory instead of the true size.)
107    
108    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
109        ovector size, it uses memory at the end of the block that it has got.
110    
111    29. Check for an overlong MARK name and give an error at compile time. The
112        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
113    
114    30. JIT compiler update.
115    
116    
117    Version 8.30 04-February-2012
118    -----------------------------
119    
120    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
121        name is defined in ctype.h.
122    
123    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
124        only in quite long subpatterns.
125    
126    3.  Removed the function pcre_info(), which has been obsolete and deprecated
127        since it was replaced by pcre_fullinfo() in February 2000.
128    
129    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
130        match a (*MARK), and the match failed at the start of the subject, a
131        reference to memory before the start of the subject could occur. This bug
132        was introduced by fix 17 of release 8.21.
133    
134    5.  A reference to an unset group with zero minimum repetition was giving
135        totally wrong answers (in non-JavaScript-compatibility mode). For example,
136        /(another)?(\1?)test/ matched against "hello world test". This bug was
137        introduced in release 8.13.
138    
139    6.  Add support for 16-bit character strings (a large amount of work involving
140        many changes and refactorings).
141    
142    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
143        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
144        from a file.
145    
146    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
147        rounding is not applied in this particular case).
148    
149    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
150        if they appear, or are escaped, in patterns.
151    
152    10. Get rid of a number of -Wunused-but-set-variable warnings.
153    
154    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
155        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
156        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
157        also returns the mark "x". This bug applied to capturing parentheses,
158        non-capturing parentheses, and atomic parentheses. It also applied to some
159        assertions.
160    
161    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
162        information out of configure.ac instead of relying on pcre.h.generic, which
163        is not stored in the repository.
164    
165    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
166        -lreadline.
167    
168    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
169    
170    15. Applied Graycode's patch to put the top-level frame on the stack rather
171        than the heap when not using the stack for recursion. This gives a
172        performance improvement in many cases when recursion is not deep.
173    
174    16. Experimental code added to "pcretest -C" to output the stack frame size.
175    
176    
177    Version 8.21 12-Dec-2011
178    ------------------------
179    
180    1.  Updating the JIT compiler.
181    
182    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
183        are added as well.
184    
185    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
186        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
187        calling _pcre_jit_exec. Some extra comments are added.
188    
189    4.  (*MARK) settings inside atomic groups that do not contain any capturing
190        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
191        was introduced by change 18 for 8.20.
192    
193    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
194        ECMA-262 standard.
195    
196    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
197        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
198        This bug was probably introduced by change 9 of 8.13.
199    
200    7.  While fixing 6 above, I noticed that a number of other items were being
201        incorrectly rejected as "not fixed length". This arose partly because newer
202        opcodes had not been added to the fixed-length checking code. I have (a)
203        corrected the bug and added tests for these items, and (b) arranged for an
204        error to occur if an unknown opcode is encountered while checking for fixed
205        length instead of just assuming "not fixed length". The items that were
206        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
207        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
208        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
209    
210    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
211        being incorrectly compiled and would have given unpredicatble results.
212    
213    9.  A possessively repeated subpattern with minimum repeat count greater than
214        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
215        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
216        the first (A) could occur when it should not.
217    
218    10. Add a cast and remove a redundant test from the code.
219    
220    11. JIT should use pcre_malloc/pcre_free for allocation.
221    
222    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
223        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
224        is anything other than /usr, -L is still shown).
225    
226    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
227    
228    14. Perl does not support \N without a following name in a [] class; PCRE now
229        also gives an error.
230    
231    15. If a forward reference was repeated with an upper limit of around 2000,
232        it caused the error "internal error: overran compiling workspace". The
233        maximum number of forward references (including repeats) was limited by the
234        internal workspace, and dependent on the LINK_SIZE. The code has been
235        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
236        the default depends on LINK_SIZE. There is a new upper limit (for safety)
237        of around 200,000 forward references. While doing this, I also speeded up
238        the filling in of repeated forward references.
239    
240    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
241        incorrectly expecting the subject to contain another "a" after the start.
242    
243    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
244        in the match, the SKIP should be ignored. This was not happening; instead
245        the SKIP was being treated as NOMATCH. For patterns such as
246        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
247        tested.
248    
249    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
250        now much more compatible with Perl, in particular in cases where the result
251        is a non-match for a non-anchored pattern. For example, if
252        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
253        "m", where previously it did not return a name. A side effect of this
254        change is that for partial matches, the last encountered mark name is
255        returned, as for non matches. A number of tests that were previously not
256        Perl-compatible have been moved into the Perl-compatible test files. The
257        refactoring has had the pleasing side effect of removing one argument from
258        the match() function, thus reducing its stack requirements.
259    
260    19. If the /S+ option was used in pcretest to study a pattern using JIT,
261        subsequent uses of /S (without +) incorrectly behaved like /S+.
262    
263    21. Retrieve executable code size support for the JIT compiler and fixing
264        some warnings.
265    
266    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
267        not work when the shorter character appeared right at the end of the
268        subject string.
269    
270    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
271        systems.
272    
273    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
274        output it when the /M option is used in pcretest.
275    
276    25. The CheckMan script was not being included in the distribution. Also, added
277        an explicit "perl" to run Perl scripts from the PrepareRelease script
278        because this is reportedly needed in Windows.
279    
280    26. If study data was being save in a file and studying had not found a set of
281        "starts with" bytes for the pattern, the data written to the file (though
282        never used) was taken from uninitialized memory and so caused valgrind to
283        complain.
284    
285    27. Updated RunTest.bat as provided by Sheri Pierce.
286    
287    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
288    
289    29. Computation of memory usage for the table of capturing group names was
290        giving an unnecessarily large value.
291    
292    
293    Version 8.20 21-Oct-2011
294    ------------------------
295    
296    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
297        a POSIX class. After further experiments with Perl, which convinced me that
298        Perl has bugs and confusions, a closing square bracket is no longer allowed
299        in a POSIX name. This bug also affected patterns with classes that started
300        with full stops.
301    
302    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
303        captured substring, but while checking the failing first alternative,
304        substring 1 is temporarily captured. If the output vector supplied to
305        pcre_exec() was not big enough for this capture, the yield of the function
306        was still zero ("insufficient space for captured substrings"). This cannot
307        be totally fixed without adding another stack variable, which seems a lot
308        of expense for a edge case. However, I have improved the situation in cases
309        such as /(a)(b)x|abc/ matched against "abc", where the return code
310        indicates that fewer than the maximum number of slots in the ovector have
311        been set.
312    
313    3.  Related to (2) above: when there are more back references in a pattern than
314        slots in the output vector, pcre_exec() uses temporary memory during
315        matching, and copies in the captures as far as possible afterwards. It was
316        using the entire output vector, but this conflicts with the specification
317        that only 2/3 is used for passing back captured substrings. Now it uses
318        only the first 2/3, for compatibility. This is, of course, another edge
319        case.
320    
321    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
322        main code base, and can be used by building with --enable-jit. When this is
323        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
324        runtime --no-jit option is given.
325    
326    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
327        ovector, the return from the function was zero, implying that there were
328        other matches that did not fit. The correct "exactly full" value is now
329        returned.
330    
331    6.  If a subpattern that was called recursively or as a subroutine contained
332        (*PRUNE) or any other control that caused it to give a non-standard return,
333        invalid errors such as "Error -26 (nested recursion at the same subject
334        position)" or even infinite loops could occur.
335    
336    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
337        computing the minimum length on reaching *ACCEPT, and so ended up with the
338        wrong value of 1 rather than 0. Further investigation indicates that
339        computing a minimum subject length in the presence of *ACCEPT is difficult
340        (think back references, subroutine calls), and so I have changed the code
341        so that no minimum is registered for a pattern that contains *ACCEPT.
342    
343    8.  If (*THEN) was present in the first (true) branch of a conditional group,
344        it was not handled as intended. [But see 16 below.]
345    
346    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
347        Sheri Pierce.
348    
349    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
350        the first byte in a match must be "a".
351    
352    11. Change 17 for 8.13 increased the recursion depth for patterns like
353        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
354        pattern contains any instances of (*THEN). If it does not, the old
355        optimizations are restored. It would be nice to do this on a per-group
356        basis, but at the moment that is not feasible.
357    
358    12. In some environments, the output of pcretest -C is CRLF terminated. This
359        broke RunTest's code that checks for the link size. A single white space
360        character after the value is now allowed for.
361    
362    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
363        For "fr", it uses the Windows-specific input and output files.
364    
365    14. If (*THEN) appeared in a group that was called recursively or as a
366        subroutine, it did not work as intended. [But see next item.]
367    
368    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
369        pattern fragments (but not containing any | characters). If A and B are
370        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
371        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
372        D. In other words, Perl considers parentheses that do not contain any |
373        characters to be part of a surrounding alternative, whereas PCRE was
374        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
375        differently. PCRE now behaves in the same way as Perl, except in the case
376        of subroutine/recursion calls such as (?1) which have in any case always
377        been different (but PCRE had them first :-).
378    
379    16. Related to 15 above: Perl does not treat the | in a conditional group as
380        creating alternatives. Such a group is treated in the same way as an
381        ordinary group without any | characters when processing (*THEN). PCRE has
382        been changed to match Perl's behaviour.
383    
384    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
385        RunGrepTest script failed.
386    
387    18. Change 22 for version 13 caused atomic groups to use more stack. This is
388        inevitable for groups that contain captures, but it can lead to a lot of
389        stack use in large patterns. The old behaviour has been restored for atomic
390        groups that do not contain any capturing parentheses.
391    
392    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
393        suppress the check for a minimum subject length at run time. (If it was
394        given to pcre_exec() or pcre_dfa_exec() it did work.)
395    
396    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
397        fail to work when decoding hex characters in data strings in EBCDIC
398        environments.
399    
400    21. It appears that in at least one Mac OS environment, the isxdigit() function
401        is implemented as a macro that evaluates to its argument more than once,
402        contravening the C 90 Standard (I haven't checked a later standard). There
403        was an instance in pcretest which caused it to go wrong when processing
404        \x{...} escapes in subject strings. The has been rewritten to avoid using
405        things like p++ in the argument of isxdigit().
406    
407    
408    Version 8.13 16-Aug-2011
409    ------------------------
410    
411    1.  The Unicode data tables have been updated to Unicode 6.0.0.
412    
413    2.  Two minor typos in pcre_internal.h have been fixed.
414    
415    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
416        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
417        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
418    
419    4.  There were a number of related bugs in the code for matching backrefences
420        caselessly in UTF-8 mode when codes for the characters concerned were
421        different numbers of bytes. For example, U+023A and U+2C65 are an upper
422        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
423        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
424        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
425        2-byte code at the end of the subject (it thought there wasn't enough data
426        left).
427    
428    5.  Comprehensive information about what went wrong is now returned by
429        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
430        as the output vector has at least 2 elements. The offset of the start of
431        the failing character and a reason code are placed in the vector.
432    
433    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
434        now returned is for the first byte of the failing character, instead of the
435        last byte inspected. This is an incompatible change, but I hope it is small
436        enough not to be a problem. It makes the returned offset consistent with
437        pcre_exec() and pcre_dfa_exec().
438    
439    7.  pcretest now gives a text phrase as well as the error number when
440        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
441        failure, the offset and reason code are output.
442    
443    8.  When \R was used with a maximizing quantifier it failed to skip backwards
444        over a \r\n pair if the subsequent match failed. Instead, it just skipped
445        back over a single character (\n). This seems wrong (because it treated the
446        two characters as a single entity when going forwards), conflicts with the
447        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
448        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
449        has been changed.
450    
451    9.  Some internal refactoring has changed the processing so that the handling
452        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
453        time (the PCRE_DOTALL option was changed this way some time ago: version
454        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
455        which was always a bit of a fudge. It also means that there is one less
456        argument for the match() function, which reduces its stack requirements
457        slightly. This change also fixes an incompatibility with Perl: the pattern
458        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
459    
460    10. More internal refactoring has drastically reduced the number of recursive
461        calls to match() for possessively repeated groups such as (abc)++ when
462        using pcre_exec().
463    
464    11. While implementing 10, a number of bugs in the handling of groups were
465        discovered and fixed:
466    
467        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
468        (a|)*(?1) gave a compile-time internal error.
469        ((a|)+)+  did not notice that the outer group could match an empty string.
470        (^a|^)+   was not marked as anchored.
471        (.*a|.*)+ was not marked as matching at start or after a newline.
472    
473    12. Yet more internal refactoring has removed another argument from the match()
474        function. Special calls to this function are now indicated by setting a
475        value in a variable in the "match data" data block.
476    
477    13. Be more explicit in pcre_study() instead of relying on "default" for
478        opcodes that mean there is no starting character; this means that when new
479        ones are added and accidentally left out of pcre_study(), testing should
480        pick them up.
481    
482    14. The -s option of pcretest has been documented for ages as being an old
483        synonym of -m (show memory usage). I have changed it to mean "force study
484        for every regex", that is, assume /S for every regex. This is similar to -i
485        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
486        using it. It makes it easier to run collections of tests with and without
487        study enabled, and thereby test pcre_study() more easily. All the standard
488        tests are now run with and without -s (but some patterns can be marked as
489        "never study" - see 20 below).
490    
491    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
492        restoration of the capturing data to the outer values was not happening
493        correctly.
494    
495    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
496        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
497        pattern had matched an empty string, and so incorrectly returned a no
498        match.
499    
500    17. There was optimizing code for the last branch of non-capturing parentheses,
501        and also for the obeyed branch of a conditional subexpression, which used
502        tail recursion to cut down on stack usage. Unfortunately, now that there is
503        the possibility of (*THEN) occurring in these branches, tail recursion is
504        no longer possible because the return has to be checked for (*THEN). These
505        two optimizations have therefore been removed. [But see 8.20/11 above.]
506    
507    18. If a pattern containing \R was studied, it was assumed that \R always
508        matched two bytes, thus causing the minimum subject length to be
509        incorrectly computed because \R can also match just one byte.
510    
511    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
512        was incorrectly computed.
513    
514    20. If /S is present twice on a test pattern in pcretest input, it now
515        *disables* studying, thereby overriding the use of -s on the command line
516        (see 14 above). This is necessary for one or two tests to keep the output
517        identical in both cases.
518    
519    21. When (*ACCEPT) was used in an assertion that matched an empty string and
520        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
521    
522    22. When an atomic group that contained a capturing parenthesis was
523        successfully matched, but the branch in which it appeared failed, the
524        capturing was not being forgotten if a higher numbered group was later
525        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
526        group 1 to "a", when in fact it should be unset. This applied to multi-
527        branched capturing and non-capturing groups, repeated or not, and also to
528        positive assertions (capturing in negative assertions does not happen
529        in PCRE) and also to nested atomic groups.
530    
531    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
532        subject after a captured substring, to make it easier to tell which of a
533        number of identical substrings has been captured.
534    
535    24. The way atomic groups are processed by pcre_exec() has been changed so that
536        if they are repeated, backtracking one repetition now resets captured
537        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
538        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
539        "aaa". Previously, it would have been "a". As part of this code
540        refactoring, the way recursive calls are handled has also been changed.
541    
542    25. If an assertion condition captured any substrings, they were not passed
543        back unless some other capturing happened later. For example, if
544        (?(?=(a))a) was matched against "a", no capturing was returned.
545    
546    26. When studying a pattern that contained subroutine calls or assertions,
547        the code for finding the minimum length of a possible match was handling
548        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
549        group 1 called group 2 while simultaneously a separate group 2 called group
550        1). A stack overflow occurred in this case. I have fixed this by limiting
551        the recursion depth to 10.
552    
553    27. Updated RunTest.bat in the distribution to the version supplied by Tom
554        Fortmann. This supports explicit test numbers on the command line, and has
555        argument validation and error reporting.
556    
557    28. An instance of \X with an unlimited repeat could fail if at any point the
558        first character it looked at was a mark character.
559    
560    29. Some minor code refactoring concerning Unicode properties and scripts
561        should reduce the stack requirement of match() slightly.
562    
563    30. Added the '=' option to pcretest to check the setting of unused capturing
564        slots at the end of the pattern, which are documented as being -1, but are
565        not included in the return count.
566    
567    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
568        compiled something random. Now it gives a compile-time error (as does
569        Perl).
570    
571    32. A *MARK encountered during the processing of a positive assertion is now
572        recorded and passed back (compatible with Perl).
573    
574    33. If --only-matching or --colour was set on a pcregrep call whose pattern
575        had alternative anchored branches, the search for a second match in a line
576        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
577        matched the line "0102" twice. The same bug affected patterns that started
578        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
579        twice.
580    
581    34. Previously, PCRE did not allow quantification of assertions. However, Perl
582        does, and because of capturing effects, quantifying parenthesized
583        assertions may at times be useful. Quantifiers are now allowed for
584        parenthesized assertions.
585    
586    35. A minor code tidy in pcre_compile() when checking options for \R usage.
587    
588    36. \g was being checked for fancy things in a character class, when it should
589        just be a literal "g".
590    
591    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
592        appearance of a nested POSIX class supersedes an apparent external class.
593        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
594        unescaped square brackets may also appear as part of class names. For
595        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
596        more like Perl. (But see 8.20/1 above.)
597    
598    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
599        was because it thought it was \N{name}, which is not supported).
600    
601    39. Add minix to OS list not supporting the -S option in pcretest.
602    
603    40. PCRE tries to detect cases of infinite recursion at compile time, but it
604        cannot analyze patterns in sufficient detail to catch mutual recursions
605        such as ((?1))((?2)). There is now a runtime test that gives an error if a
606        subgroup is called recursively as a subpattern for a second time at the
607        same position in the subject string. In previous releases this might have
608        been caught by the recursion limit, or it might have run out of stack.
609    
610    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
611        happen only once. PCRE was, however incorrectly giving a compile time error
612        "recursive call could loop indefinitely" because it cannot analyze the
613        pattern in sufficient detail. The compile time test no longer happens when
614        PCRE is compiling a conditional subpattern, but actual runaway loops are
615        now caught at runtime (see 40 above).
616    
617    42. It seems that Perl allows any characters other than a closing parenthesis
618        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
619        has been changed to be the same.
620    
621    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
622        as not to get warnings when autogen.sh is called. Also changed
623        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
624    
625    44. To help people who use pcregrep to scan files containing exceedingly long
626        lines, the following changes have been made:
627    
628        (a) The default value of the buffer size parameter has been increased from
629            8K to 20K. (The actual buffer used is three times this size.)
630    
631        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
632            PCRE is built.
633    
634        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
635            to be set at run time.
636    
637        (d) Numerical values in pcregrep options can be followed by K or M, for
638            example --buffer-size=50K.
639    
640        (e) If a line being scanned overflows pcregrep's buffer, an error is now
641            given and the return code is set to 2.
642    
643    45. Add a pointer to the latest mark to the callout data block.
644    
645    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
646        partial match of an empty string instead of no match. This was specific to
647        the use of ".".
648    
649    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
650        complete match instead of a partial match. This bug was dependent on both
651        the PCRE_UTF8 and PCRE_DOTALL options being set.
652    
653    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
654        starting byte set, because \b was not being ignored.
655    
656    
657    Version 8.12 15-Jan-2011
658    ------------------------
659    
660    1.  Fixed some typos in the markup of the man pages, and wrote a script that
661        checks for such things as part of the documentation building process.
662    
663    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
664        --match-limit and --recursion-limit options (added for 8.11). In
665        particular, this made one of the standard tests fail. (The integer value
666        went into the wrong half of a long int.)
667    
668    3.  If the --colour option was given to pcregrep with -v (invert match), it
669        did strange things, either producing crazy output, or crashing. It should,
670        of course, ignore a request for colour when reporting lines that do not
671        match.
672    
673    4.  Another pcregrep bug caused similar problems if --colour was specified with
674        -M (multiline) and the pattern match finished with a line ending.
675    
676    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
677        matched in multiline mode, the following line was shown as part of the
678        match. This seems wrong, so I have changed it.
679    
680    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
681        the check for further matches in the same line (so they could be coloured)
682        to overrun the end of the current line. If another match was found, it was
683        incorrectly shown (and then shown again when found in the next line).
684    
685    7.  If pcregrep was compiled under Windows, there was a reference to the
686        function pcregrep_exit() before it was defined. I am assuming this was
687        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
688        reported by a user. I've moved the definition above the reference.
689    
690    
691    Version 8.11 10-Dec-2010
692    ------------------------
693    
694    1.  (*THEN) was not working properly if there were untried alternatives prior
695        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
696        backtracked to try for "b" instead of moving to the next alternative branch
697        at the same level (in this case, to look for "c"). The Perl documentation
698        is clear that when (*THEN) is backtracked onto, it goes to the "next
699        alternative in the innermost enclosing group".
700    
701    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
702        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
703        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
704        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
705        (*THEN).
706    
707    3.  If \s appeared in a character class, it removed the VT character from
708        the class, even if it had been included by some previous item, for example
709        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
710        of \s, but is part of the POSIX "space" class.)
711    
712    4.  A partial match never returns an empty string (because you can always
713        match an empty string at the end of the subject); however the checking for
714        an empty string was starting at the "start of match" point. This has been
715        changed to the "earliest inspected character" point, because the returned
716        data for a partial match starts at this character. This means that, for
717        example, /(?<=abc)def/ gives a partial match for the subject "abc"
718        (previously it gave "no match").
719    
720    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
721        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
722        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
723        has an implication that the given string is incomplete (because a partial
724        match is preferred over a full match). For this reason, these items now
725        give a partial match in this situation. [Aside: previously, the one case
726        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
727        match rather than a full match, which was wrong by the old rules, but is
728        now correct.]
729    
730    6.  There was a bug in the handling of #-introduced comments, recognized when
731        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
732        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
733        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
734        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
735        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
736        places in pcre_compile().
737    
738    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
739        comments when looking ahead for named forward references to subpatterns,
740        the only newline sequence it recognized was NL. It now handles newlines
741        according to the set newline convention.
742    
743    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
744        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
745        cater for a lack of strerror(). These oversights have been fixed.
746    
747    9.  Added --match-limit and --recursion-limit to pcregrep.
748    
749    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
750    
751    11. When the -o option was used, pcregrep was setting a return code of 1, even
752        when matches were found, and --line-buffered was not being honoured.
753    
754    12. Added an optional parentheses number to the -o and --only-matching options
755        of pcregrep.
756    
757    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
758        can match an empty string. The code to do it in pcretest and pcredemo
759        needed fixing:
760    
761        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
762            only one byte after an empty string match just before CRLF (this case
763            just got forgotten; "any" and "anycrlf" were OK).
764    
765        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
766            mode when an empty string match preceded an ASCII character followed by
767            a non-ASCII character. (The code for advancing by one character rather
768            than one byte was nonsense.)
769    
770        (c) The pcredemo.c sample program did not have any code at all to handle
771            the cases when CRLF is a valid newline sequence.
772    
773    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
774        as a starting offset was within the subject string. There is now a new
775        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
776        negative or greater than the length of the string. In order to test this,
777        pcretest is extended to allow the setting of negative starting offsets.
778    
779    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
780        starting offset points to the beginning of a UTF-8 character was
781        unnecessarily clumsy. I tidied it up.
782    
783    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
784        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
785    
786    17. Nobody had reported that the --include_dir option, which was added in
787        release 7.7 should have been called --include-dir (hyphen, not underscore)
788        for compatibility with GNU grep. I have changed it to --include-dir, but
789        left --include_dir as an undocumented synonym, and the same for
790        --exclude-dir, though that is not available in GNU grep, at least as of
791        release 2.5.4.
792    
793    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
794        characters from a string of bytes) have been redefined so as not to use
795        loops, in order to improve performance in some environments. At the same
796        time, I abstracted some of the common code into auxiliary macros to save
797        repetition (this should not affect the compiled code).
798    
799    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
800        compile-time error is now given if \c is not followed by an ASCII
801        character, that is, a byte less than 128. (In EBCDIC mode, the code is
802        different, and any byte value is allowed.)
803    
804    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
805        START_OPTIMIZE option, which is now allowed at compile time - but just
806        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
807        to pcregrep and other applications that have no direct access to PCRE
808        options. The new /Y option in pcretest sets this option when calling
809        pcre_compile().
810    
811    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
812        back references. Groups containing recursive back references were forced to
813        be atomic by that change, but in the case of named groups, the amount of
814        memory required was incorrectly computed, leading to "Failed: internal
815        error: code overflow". This has been fixed.
816    
817    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
818        pcretest.c, to avoid build problems in some Borland environments.
819    
820    
821    Version 8.10 25-Jun-2010
822    ------------------------
823    
824    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
825        THEN.
826    
827    2.  (*ACCEPT) was not working when inside an atomic group.
828    
829    3.  Inside a character class, \B is treated as a literal by default, but
830        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
831        causes the error). The code is unchanged, but I tidied the documentation.
832    
833    4.  Inside a character class, PCRE always treated \R and \X as literals,
834        whereas Perl faults them if its -w option is set. I have changed PCRE so
835        that it faults them when PCRE_EXTRA is set.
836    
837    5.  Added support for \N, which always matches any character other than
838        newline. (It is the same as "." when PCRE_DOTALL is not set.)
839    
840    6.  When compiling pcregrep with newer versions of gcc which may have
841        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
842        declared with attribute warn_unused_result" were given. Just casting the
843        result to (void) does not stop the warnings; a more elaborate fudge is
844        needed. I've used a macro to implement this.
845    
846    7.  Minor change to pcretest.c to avoid a compiler warning.
847    
848    8.  Added four artifical Unicode properties to help with an option to make
849        \s etc use properties (see next item). The new properties are: Xan
850        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
851    
852    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
853        use Unicode properties. (*UCP) at the start of a pattern can be used to set
854        this option. Modified pcretest to add /W to test this facility. Added
855        REG_UCP to make it available via the POSIX interface.
856    
857    10. Added --line-buffered to pcregrep.
858    
859    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
860        studied, and the match started with a letter with a code point greater than
861        127 whose first byte was different to the first byte of the other case of
862        the letter, the other case of this starting letter was not recognized
863        (#976).
864    
865    12. If a pattern that was studied started with a repeated Unicode property
866        test, for example, \p{Nd}+, there was the theoretical possibility of
867        setting up an incorrect bitmap of starting bytes, but fortunately it could
868        not have actually happened in practice until change 8 above was made (it
869        added property types that matched character-matching opcodes).
870    
871    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
872        possible starting bytes for non-anchored patterns.
873    
874    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
875        \R, and also a number of cases that involve Unicode properties, both
876        explicit and implicit when PCRE_UCP is set.
877    
878    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
879        input, it could crash or give wrong results if characters with values
880        greater than 0xc0 were present in the subject string. (Detail: it assumed
881        UTF-8 input when processing these items.)
882    
883    16. Added a lot of (int) casts to avoid compiler warnings in systems where
884        size_t is 64-bit (#991).
885    
886    17. Added a check for running out of memory when PCRE is compiled with
887        --disable-stack-for-recursion (#990).
888    
889    18. If the last data line in a file for pcretest does not have a newline on
890        the end, a newline was missing in the output.
891    
892    19. The default pcre_chartables.c file recognizes only ASCII characters (values
893        less than 128) in its various bitmaps. However, there is a facility for
894        generating tables according to the current locale when PCRE is compiled. It
895        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
896        characters, are recognized by isspace() and therefore were getting set in
897        these tables, and indeed these tables seem to approximate to ISO 8859. This
898        caused a problem in UTF-8 mode when pcre_study() was used to create a list
899        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
900        which of course cannot start UTF-8 characters. I have changed the code so
901        that only real ASCII characters (less than 128) and the correct starting
902        bytes for UTF-8 encodings are set for characters greater than 127 when in
903        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
904        altogether.)
905    
906    20. Added the /T option to pcretest so as to be able to run tests with non-
907        standard character tables, thus making it possible to include the tests
908        used for 19 above in the standard set of tests.
909    
910    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
911        reference to a subpattern the other side of a comment that contains an
912        opening parenthesis caused either an internal compiling error, or a
913        reference to the wrong subpattern.
914    
915    
916    Version 8.02 19-Mar-2010
917  ------------------------  ------------------------
918    
919  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.

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