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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-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    
79    Version 8.30 04-February-2012
80    -----------------------------
81    
82    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
83        name is defined in ctype.h.
84    
85    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
86        only in quite long subpatterns.
87    
88    3.  Removed the function pcre_info(), which has been obsolete and deprecated
89        since it was replaced by pcre_fullinfo() in February 2000.
90    
91    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
92        match a (*MARK), and the match failed at the start of the subject, a
93        reference to memory before the start of the subject could occur. This bug
94        was introduced by fix 17 of release 8.21.
95    
96    5.  A reference to an unset group with zero minimum repetition was giving
97        totally wrong answers (in non-JavaScript-compatibility mode). For example,
98        /(another)?(\1?)test/ matched against "hello world test". This bug was
99        introduced in release 8.13.
100    
101    6.  Add support for 16-bit character strings (a large amount of work involving
102        many changes and refactorings).
103    
104    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
105        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
106        from a file.
107    
108    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
109        rounding is not applied in this particular case).
110    
111    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
112        if they appear, or are escaped, in patterns.
113    
114    10. Get rid of a number of -Wunused-but-set-variable warnings.
115    
116    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
117        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
118        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
119        also returns the mark "x". This bug applied to capturing parentheses,
120        non-capturing parentheses, and atomic parentheses. It also applied to some
121        assertions.
122    
123    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
124        information out of configure.ac instead of relying on pcre.h.generic, which
125        is not stored in the repository.
126    
127    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
128        -lreadline.
129    
130    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
131    
132    15. Applied Graycode's patch to put the top-level frame on the stack rather
133        than the heap when not using the stack for recursion. This gives a
134        performance improvement in many cases when recursion is not deep.
135    
136    16. Experimental code added to "pcretest -C" to output the stack frame size.
137    
138    
139    Version 8.21 12-Dec-2011
140    ------------------------
141    
142    1.  Updating the JIT compiler.
143    
144    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
145        are added as well.
146    
147    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
148        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
149        calling _pcre_jit_exec. Some extra comments are added.
150    
151    4.  (*MARK) settings inside atomic groups that do not contain any capturing
152        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
153        was introduced by change 18 for 8.20.
154    
155    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
156        ECMA-262 standard.
157    
158    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
159        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
160        This bug was probably introduced by change 9 of 8.13.
161    
162    7.  While fixing 6 above, I noticed that a number of other items were being
163        incorrectly rejected as "not fixed length". This arose partly because newer
164        opcodes had not been added to the fixed-length checking code. I have (a)
165        corrected the bug and added tests for these items, and (b) arranged for an
166        error to occur if an unknown opcode is encountered while checking for fixed
167        length instead of just assuming "not fixed length". The items that were
168        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
169        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
170        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
171    
172    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
173        being incorrectly compiled and would have given unpredicatble results.
174    
175    9.  A possessively repeated subpattern with minimum repeat count greater than
176        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
177        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
178        the first (A) could occur when it should not.
179    
180    10. Add a cast and remove a redundant test from the code.
181    
182    11. JIT should use pcre_malloc/pcre_free for allocation.
183    
184    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
185        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
186        is anything other than /usr, -L is still shown).
187    
188    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
189    
190    14. Perl does not support \N without a following name in a [] class; PCRE now
191        also gives an error.
192    
193    15. If a forward reference was repeated with an upper limit of around 2000,
194        it caused the error "internal error: overran compiling workspace". The
195        maximum number of forward references (including repeats) was limited by the
196        internal workspace, and dependent on the LINK_SIZE. The code has been
197        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
198        the default depends on LINK_SIZE. There is a new upper limit (for safety)
199        of around 200,000 forward references. While doing this, I also speeded up
200        the filling in of repeated forward references.
201    
202    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
203        incorrectly expecting the subject to contain another "a" after the start.
204    
205    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
206        in the match, the SKIP should be ignored. This was not happening; instead
207        the SKIP was being treated as NOMATCH. For patterns such as
208        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
209        tested.
210    
211    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
212        now much more compatible with Perl, in particular in cases where the result
213        is a non-match for a non-anchored pattern. For example, if
214        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
215        "m", where previously it did not return a name. A side effect of this
216        change is that for partial matches, the last encountered mark name is
217        returned, as for non matches. A number of tests that were previously not
218        Perl-compatible have been moved into the Perl-compatible test files. The
219        refactoring has had the pleasing side effect of removing one argument from
220        the match() function, thus reducing its stack requirements.
221    
222    19. If the /S+ option was used in pcretest to study a pattern using JIT,
223        subsequent uses of /S (without +) incorrectly behaved like /S+.
224    
225    21. Retrieve executable code size support for the JIT compiler and fixing
226        some warnings.
227    
228    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
229        not work when the shorter character appeared right at the end of the
230        subject string.
231    
232    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
233        systems.
234    
235    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
236        output it when the /M option is used in pcretest.
237    
238    25. The CheckMan script was not being included in the distribution. Also, added
239        an explicit "perl" to run Perl scripts from the PrepareRelease script
240        because this is reportedly needed in Windows.
241    
242    26. If study data was being save in a file and studying had not found a set of
243        "starts with" bytes for the pattern, the data written to the file (though
244        never used) was taken from uninitialized memory and so caused valgrind to
245        complain.
246    
247    27. Updated RunTest.bat as provided by Sheri Pierce.
248    
249    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
250    
251    29. Computation of memory usage for the table of capturing group names was
252        giving an unnecessarily large value.
253    
254    
255    Version 8.20 21-Oct-2011
256    ------------------------
257    
258    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
259        a POSIX class. After further experiments with Perl, which convinced me that
260        Perl has bugs and confusions, a closing square bracket is no longer allowed
261        in a POSIX name. This bug also affected patterns with classes that started
262        with full stops.
263    
264    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
265        captured substring, but while checking the failing first alternative,
266        substring 1 is temporarily captured. If the output vector supplied to
267        pcre_exec() was not big enough for this capture, the yield of the function
268        was still zero ("insufficient space for captured substrings"). This cannot
269        be totally fixed without adding another stack variable, which seems a lot
270        of expense for a edge case. However, I have improved the situation in cases
271        such as /(a)(b)x|abc/ matched against "abc", where the return code
272        indicates that fewer than the maximum number of slots in the ovector have
273        been set.
274    
275    3.  Related to (2) above: when there are more back references in a pattern than
276        slots in the output vector, pcre_exec() uses temporary memory during
277        matching, and copies in the captures as far as possible afterwards. It was
278        using the entire output vector, but this conflicts with the specification
279        that only 2/3 is used for passing back captured substrings. Now it uses
280        only the first 2/3, for compatibility. This is, of course, another edge
281        case.
282    
283    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
284        main code base, and can be used by building with --enable-jit. When this is
285        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
286        runtime --no-jit option is given.
287    
288    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
289        ovector, the return from the function was zero, implying that there were
290        other matches that did not fit. The correct "exactly full" value is now
291        returned.
292    
293    6.  If a subpattern that was called recursively or as a subroutine contained
294        (*PRUNE) or any other control that caused it to give a non-standard return,
295        invalid errors such as "Error -26 (nested recursion at the same subject
296        position)" or even infinite loops could occur.
297    
298    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
299        computing the minimum length on reaching *ACCEPT, and so ended up with the
300        wrong value of 1 rather than 0. Further investigation indicates that
301        computing a minimum subject length in the presence of *ACCEPT is difficult
302        (think back references, subroutine calls), and so I have changed the code
303        so that no minimum is registered for a pattern that contains *ACCEPT.
304    
305    8.  If (*THEN) was present in the first (true) branch of a conditional group,
306        it was not handled as intended. [But see 16 below.]
307    
308    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
309        Sheri Pierce.
310    
311    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
312        the first byte in a match must be "a".
313    
314    11. Change 17 for 8.13 increased the recursion depth for patterns like
315        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
316        pattern contains any instances of (*THEN). If it does not, the old
317        optimizations are restored. It would be nice to do this on a per-group
318        basis, but at the moment that is not feasible.
319    
320    12. In some environments, the output of pcretest -C is CRLF terminated. This
321        broke RunTest's code that checks for the link size. A single white space
322        character after the value is now allowed for.
323    
324    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
325        For "fr", it uses the Windows-specific input and output files.
326    
327    14. If (*THEN) appeared in a group that was called recursively or as a
328        subroutine, it did not work as intended. [But see next item.]
329    
330    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
331        pattern fragments (but not containing any | characters). If A and B are
332        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
333        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
334        D. In other words, Perl considers parentheses that do not contain any |
335        characters to be part of a surrounding alternative, whereas PCRE was
336        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
337        differently. PCRE now behaves in the same way as Perl, except in the case
338        of subroutine/recursion calls such as (?1) which have in any case always
339        been different (but PCRE had them first :-).
340    
341    16. Related to 15 above: Perl does not treat the | in a conditional group as
342        creating alternatives. Such a group is treated in the same way as an
343        ordinary group without any | characters when processing (*THEN). PCRE has
344        been changed to match Perl's behaviour.
345    
346    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
347        RunGrepTest script failed.
348    
349    18. Change 22 for version 13 caused atomic groups to use more stack. This is
350        inevitable for groups that contain captures, but it can lead to a lot of
351        stack use in large patterns. The old behaviour has been restored for atomic
352        groups that do not contain any capturing parentheses.
353    
354    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
355        suppress the check for a minimum subject length at run time. (If it was
356        given to pcre_exec() or pcre_dfa_exec() it did work.)
357    
358    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
359        fail to work when decoding hex characters in data strings in EBCDIC
360        environments.
361    
362    21. It appears that in at least one Mac OS environment, the isxdigit() function
363        is implemented as a macro that evaluates to its argument more than once,
364        contravening the C 90 Standard (I haven't checked a later standard). There
365        was an instance in pcretest which caused it to go wrong when processing
366        \x{...} escapes in subject strings. The has been rewritten to avoid using
367        things like p++ in the argument of isxdigit().
368    
369    
370    Version 8.13 16-Aug-2011
371    ------------------------
372    
373    1.  The Unicode data tables have been updated to Unicode 6.0.0.
374    
375    2.  Two minor typos in pcre_internal.h have been fixed.
376    
377    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
378        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
379        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
380    
381    4.  There were a number of related bugs in the code for matching backrefences
382        caselessly in UTF-8 mode when codes for the characters concerned were
383        different numbers of bytes. For example, U+023A and U+2C65 are an upper
384        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
385        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
386        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
387        2-byte code at the end of the subject (it thought there wasn't enough data
388        left).
389    
390    5.  Comprehensive information about what went wrong is now returned by
391        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
392        as the output vector has at least 2 elements. The offset of the start of
393        the failing character and a reason code are placed in the vector.
394    
395    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
396        now returned is for the first byte of the failing character, instead of the
397        last byte inspected. This is an incompatible change, but I hope it is small
398        enough not to be a problem. It makes the returned offset consistent with
399        pcre_exec() and pcre_dfa_exec().
400    
401    7.  pcretest now gives a text phrase as well as the error number when
402        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
403        failure, the offset and reason code are output.
404    
405    8.  When \R was used with a maximizing quantifier it failed to skip backwards
406        over a \r\n pair if the subsequent match failed. Instead, it just skipped
407        back over a single character (\n). This seems wrong (because it treated the
408        two characters as a single entity when going forwards), conflicts with the
409        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
410        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
411        has been changed.
412    
413    9.  Some internal refactoring has changed the processing so that the handling
414        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
415        time (the PCRE_DOTALL option was changed this way some time ago: version
416        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
417        which was always a bit of a fudge. It also means that there is one less
418        argument for the match() function, which reduces its stack requirements
419        slightly. This change also fixes an incompatibility with Perl: the pattern
420        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
421    
422    10. More internal refactoring has drastically reduced the number of recursive
423        calls to match() for possessively repeated groups such as (abc)++ when
424        using pcre_exec().
425    
426    11. While implementing 10, a number of bugs in the handling of groups were
427        discovered and fixed:
428    
429        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
430        (a|)*(?1) gave a compile-time internal error.
431        ((a|)+)+  did not notice that the outer group could match an empty string.
432        (^a|^)+   was not marked as anchored.
433        (.*a|.*)+ was not marked as matching at start or after a newline.
434    
435    12. Yet more internal refactoring has removed another argument from the match()
436        function. Special calls to this function are now indicated by setting a
437        value in a variable in the "match data" data block.
438    
439    13. Be more explicit in pcre_study() instead of relying on "default" for
440        opcodes that mean there is no starting character; this means that when new
441        ones are added and accidentally left out of pcre_study(), testing should
442        pick them up.
443    
444    14. The -s option of pcretest has been documented for ages as being an old
445        synonym of -m (show memory usage). I have changed it to mean "force study
446        for every regex", that is, assume /S for every regex. This is similar to -i
447        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
448        using it. It makes it easier to run collections of tests with and without
449        study enabled, and thereby test pcre_study() more easily. All the standard
450        tests are now run with and without -s (but some patterns can be marked as
451        "never study" - see 20 below).
452    
453    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
454        restoration of the capturing data to the outer values was not happening
455        correctly.
456    
457    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
458        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
459        pattern had matched an empty string, and so incorrectly returned a no
460        match.
461    
462    17. There was optimizing code for the last branch of non-capturing parentheses,
463        and also for the obeyed branch of a conditional subexpression, which used
464        tail recursion to cut down on stack usage. Unfortunately, now that there is
465        the possibility of (*THEN) occurring in these branches, tail recursion is
466        no longer possible because the return has to be checked for (*THEN). These
467        two optimizations have therefore been removed. [But see 8.20/11 above.]
468    
469    18. If a pattern containing \R was studied, it was assumed that \R always
470        matched two bytes, thus causing the minimum subject length to be
471        incorrectly computed because \R can also match just one byte.
472    
473    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
474        was incorrectly computed.
475    
476    20. If /S is present twice on a test pattern in pcretest input, it now
477        *disables* studying, thereby overriding the use of -s on the command line
478        (see 14 above). This is necessary for one or two tests to keep the output
479        identical in both cases.
480    
481    21. When (*ACCEPT) was used in an assertion that matched an empty string and
482        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
483    
484    22. When an atomic group that contained a capturing parenthesis was
485        successfully matched, but the branch in which it appeared failed, the
486        capturing was not being forgotten if a higher numbered group was later
487        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
488        group 1 to "a", when in fact it should be unset. This applied to multi-
489        branched capturing and non-capturing groups, repeated or not, and also to
490        positive assertions (capturing in negative assertions does not happen
491        in PCRE) and also to nested atomic groups.
492    
493    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
494        subject after a captured substring, to make it easier to tell which of a
495        number of identical substrings has been captured.
496    
497    24. The way atomic groups are processed by pcre_exec() has been changed so that
498        if they are repeated, backtracking one repetition now resets captured
499        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
500        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
501        "aaa". Previously, it would have been "a". As part of this code
502        refactoring, the way recursive calls are handled has also been changed.
503    
504    25. If an assertion condition captured any substrings, they were not passed
505        back unless some other capturing happened later. For example, if
506        (?(?=(a))a) was matched against "a", no capturing was returned.
507    
508    26. When studying a pattern that contained subroutine calls or assertions,
509        the code for finding the minimum length of a possible match was handling
510        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
511        group 1 called group 2 while simultaneously a separate group 2 called group
512        1). A stack overflow occurred in this case. I have fixed this by limiting
513        the recursion depth to 10.
514    
515    27. Updated RunTest.bat in the distribution to the version supplied by Tom
516        Fortmann. This supports explicit test numbers on the command line, and has
517        argument validation and error reporting.
518    
519    28. An instance of \X with an unlimited repeat could fail if at any point the
520        first character it looked at was a mark character.
521    
522    29. Some minor code refactoring concerning Unicode properties and scripts
523        should reduce the stack requirement of match() slightly.
524    
525    30. Added the '=' option to pcretest to check the setting of unused capturing
526        slots at the end of the pattern, which are documented as being -1, but are
527        not included in the return count.
528    
529    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
530        compiled something random. Now it gives a compile-time error (as does
531        Perl).
532    
533    32. A *MARK encountered during the processing of a positive assertion is now
534        recorded and passed back (compatible with Perl).
535    
536    33. If --only-matching or --colour was set on a pcregrep call whose pattern
537        had alternative anchored branches, the search for a second match in a line
538        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
539        matched the line "0102" twice. The same bug affected patterns that started
540        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
541        twice.
542    
543    34. Previously, PCRE did not allow quantification of assertions. However, Perl
544        does, and because of capturing effects, quantifying parenthesized
545        assertions may at times be useful. Quantifiers are now allowed for
546        parenthesized assertions.
547    
548    35. A minor code tidy in pcre_compile() when checking options for \R usage.
549    
550    36. \g was being checked for fancy things in a character class, when it should
551        just be a literal "g".
552    
553    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
554        appearance of a nested POSIX class supersedes an apparent external class.
555        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
556        unescaped square brackets may also appear as part of class names. For
557        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
558        more like Perl. (But see 8.20/1 above.)
559    
560    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
561        was because it thought it was \N{name}, which is not supported).
562    
563    39. Add minix to OS list not supporting the -S option in pcretest.
564    
565    40. PCRE tries to detect cases of infinite recursion at compile time, but it
566        cannot analyze patterns in sufficient detail to catch mutual recursions
567        such as ((?1))((?2)). There is now a runtime test that gives an error if a
568        subgroup is called recursively as a subpattern for a second time at the
569        same position in the subject string. In previous releases this might have
570        been caught by the recursion limit, or it might have run out of stack.
571    
572    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
573        happen only once. PCRE was, however incorrectly giving a compile time error
574        "recursive call could loop indefinitely" because it cannot analyze the
575        pattern in sufficient detail. The compile time test no longer happens when
576        PCRE is compiling a conditional subpattern, but actual runaway loops are
577        now caught at runtime (see 40 above).
578    
579    42. It seems that Perl allows any characters other than a closing parenthesis
580        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
581        has been changed to be the same.
582    
583    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
584        as not to get warnings when autogen.sh is called. Also changed
585        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
586    
587    44. To help people who use pcregrep to scan files containing exceedingly long
588        lines, the following changes have been made:
589    
590        (a) The default value of the buffer size parameter has been increased from
591            8K to 20K. (The actual buffer used is three times this size.)
592    
593        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
594            PCRE is built.
595    
596        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
597            to be set at run time.
598    
599        (d) Numerical values in pcregrep options can be followed by K or M, for
600            example --buffer-size=50K.
601    
602        (e) If a line being scanned overflows pcregrep's buffer, an error is now
603            given and the return code is set to 2.
604    
605    45. Add a pointer to the latest mark to the callout data block.
606    
607    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
608        partial match of an empty string instead of no match. This was specific to
609        the use of ".".
610    
611    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
612        complete match instead of a partial match. This bug was dependent on both
613        the PCRE_UTF8 and PCRE_DOTALL options being set.
614    
615    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
616        starting byte set, because \b was not being ignored.
617    
618    
619    Version 8.12 15-Jan-2011
620    ------------------------
621    
622    1.  Fixed some typos in the markup of the man pages, and wrote a script that
623        checks for such things as part of the documentation building process.
624    
625    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
626        --match-limit and --recursion-limit options (added for 8.11). In
627        particular, this made one of the standard tests fail. (The integer value
628        went into the wrong half of a long int.)
629    
630    3.  If the --colour option was given to pcregrep with -v (invert match), it
631        did strange things, either producing crazy output, or crashing. It should,
632        of course, ignore a request for colour when reporting lines that do not
633        match.
634    
635    4.  Another pcregrep bug caused similar problems if --colour was specified with
636        -M (multiline) and the pattern match finished with a line ending.
637    
638    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
639        matched in multiline mode, the following line was shown as part of the
640        match. This seems wrong, so I have changed it.
641    
642    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
643        the check for further matches in the same line (so they could be coloured)
644        to overrun the end of the current line. If another match was found, it was
645        incorrectly shown (and then shown again when found in the next line).
646    
647    7.  If pcregrep was compiled under Windows, there was a reference to the
648        function pcregrep_exit() before it was defined. I am assuming this was
649        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
650        reported by a user. I've moved the definition above the reference.
651    
652    
653    Version 8.11 10-Dec-2010
654    ------------------------
655    
656    1.  (*THEN) was not working properly if there were untried alternatives prior
657        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
658        backtracked to try for "b" instead of moving to the next alternative branch
659        at the same level (in this case, to look for "c"). The Perl documentation
660        is clear that when (*THEN) is backtracked onto, it goes to the "next
661        alternative in the innermost enclosing group".
662    
663    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
664        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
665        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
666        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
667        (*THEN).
668    
669    3.  If \s appeared in a character class, it removed the VT character from
670        the class, even if it had been included by some previous item, for example
671        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
672        of \s, but is part of the POSIX "space" class.)
673    
674    4.  A partial match never returns an empty string (because you can always
675        match an empty string at the end of the subject); however the checking for
676        an empty string was starting at the "start of match" point. This has been
677        changed to the "earliest inspected character" point, because the returned
678        data for a partial match starts at this character. This means that, for
679        example, /(?<=abc)def/ gives a partial match for the subject "abc"
680        (previously it gave "no match").
681    
682    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
683        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
684        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
685        has an implication that the given string is incomplete (because a partial
686        match is preferred over a full match). For this reason, these items now
687        give a partial match in this situation. [Aside: previously, the one case
688        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
689        match rather than a full match, which was wrong by the old rules, but is
690        now correct.]
691    
692    6.  There was a bug in the handling of #-introduced comments, recognized when
693        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
694        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
695        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
696        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
697        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
698        places in pcre_compile().
699    
700    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
701        comments when looking ahead for named forward references to subpatterns,
702        the only newline sequence it recognized was NL. It now handles newlines
703        according to the set newline convention.
704    
705    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
706        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
707        cater for a lack of strerror(). These oversights have been fixed.
708    
709    9.  Added --match-limit and --recursion-limit to pcregrep.
710    
711    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
712    
713    11. When the -o option was used, pcregrep was setting a return code of 1, even
714        when matches were found, and --line-buffered was not being honoured.
715    
716    12. Added an optional parentheses number to the -o and --only-matching options
717        of pcregrep.
718    
719    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
720        can match an empty string. The code to do it in pcretest and pcredemo
721        needed fixing:
722    
723        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
724            only one byte after an empty string match just before CRLF (this case
725            just got forgotten; "any" and "anycrlf" were OK).
726    
727        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
728            mode when an empty string match preceded an ASCII character followed by
729            a non-ASCII character. (The code for advancing by one character rather
730            than one byte was nonsense.)
731    
732        (c) The pcredemo.c sample program did not have any code at all to handle
733            the cases when CRLF is a valid newline sequence.
734    
735    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
736        as a starting offset was within the subject string. There is now a new
737        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
738        negative or greater than the length of the string. In order to test this,
739        pcretest is extended to allow the setting of negative starting offsets.
740    
741    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
742        starting offset points to the beginning of a UTF-8 character was
743        unnecessarily clumsy. I tidied it up.
744    
745    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
746        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
747    
748    17. Nobody had reported that the --include_dir option, which was added in
749        release 7.7 should have been called --include-dir (hyphen, not underscore)
750        for compatibility with GNU grep. I have changed it to --include-dir, but
751        left --include_dir as an undocumented synonym, and the same for
752        --exclude-dir, though that is not available in GNU grep, at least as of
753        release 2.5.4.
754    
755    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
756        characters from a string of bytes) have been redefined so as not to use
757        loops, in order to improve performance in some environments. At the same
758        time, I abstracted some of the common code into auxiliary macros to save
759        repetition (this should not affect the compiled code).
760    
761    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
762        compile-time error is now given if \c is not followed by an ASCII
763        character, that is, a byte less than 128. (In EBCDIC mode, the code is
764        different, and any byte value is allowed.)
765    
766    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
767        START_OPTIMIZE option, which is now allowed at compile time - but just
768        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
769        to pcregrep and other applications that have no direct access to PCRE
770        options. The new /Y option in pcretest sets this option when calling
771        pcre_compile().
772    
773    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
774        back references. Groups containing recursive back references were forced to
775        be atomic by that change, but in the case of named groups, the amount of
776        memory required was incorrectly computed, leading to "Failed: internal
777        error: code overflow". This has been fixed.
778    
779    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
780        pcretest.c, to avoid build problems in some Borland environments.
781    
782    
783    Version 8.10 25-Jun-2010
784    ------------------------
785    
786    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
787        THEN.
788    
789    2.  (*ACCEPT) was not working when inside an atomic group.
790    
791    3.  Inside a character class, \B is treated as a literal by default, but
792        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
793        causes the error). The code is unchanged, but I tidied the documentation.
794    
795    4.  Inside a character class, PCRE always treated \R and \X as literals,
796        whereas Perl faults them if its -w option is set. I have changed PCRE so
797        that it faults them when PCRE_EXTRA is set.
798    
799    5.  Added support for \N, which always matches any character other than
800        newline. (It is the same as "." when PCRE_DOTALL is not set.)
801    
802    6.  When compiling pcregrep with newer versions of gcc which may have
803        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
804        declared with attribute warn_unused_result" were given. Just casting the
805        result to (void) does not stop the warnings; a more elaborate fudge is
806        needed. I've used a macro to implement this.
807    
808    7.  Minor change to pcretest.c to avoid a compiler warning.
809    
810    8.  Added four artifical Unicode properties to help with an option to make
811        \s etc use properties (see next item). The new properties are: Xan
812        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
813    
814    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
815        use Unicode properties. (*UCP) at the start of a pattern can be used to set
816        this option. Modified pcretest to add /W to test this facility. Added
817        REG_UCP to make it available via the POSIX interface.
818    
819    10. Added --line-buffered to pcregrep.
820    
821    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
822        studied, and the match started with a letter with a code point greater than
823        127 whose first byte was different to the first byte of the other case of
824        the letter, the other case of this starting letter was not recognized
825        (#976).
826    
827    12. If a pattern that was studied started with a repeated Unicode property
828        test, for example, \p{Nd}+, there was the theoretical possibility of
829        setting up an incorrect bitmap of starting bytes, but fortunately it could
830        not have actually happened in practice until change 8 above was made (it
831        added property types that matched character-matching opcodes).
832    
833    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
834        possible starting bytes for non-anchored patterns.
835    
836    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
837        \R, and also a number of cases that involve Unicode properties, both
838        explicit and implicit when PCRE_UCP is set.
839    
840    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
841        input, it could crash or give wrong results if characters with values
842        greater than 0xc0 were present in the subject string. (Detail: it assumed
843        UTF-8 input when processing these items.)
844    
845    16. Added a lot of (int) casts to avoid compiler warnings in systems where
846        size_t is 64-bit (#991).
847    
848    17. Added a check for running out of memory when PCRE is compiled with
849        --disable-stack-for-recursion (#990).
850    
851    18. If the last data line in a file for pcretest does not have a newline on
852        the end, a newline was missing in the output.
853    
854    19. The default pcre_chartables.c file recognizes only ASCII characters (values
855        less than 128) in its various bitmaps. However, there is a facility for
856        generating tables according to the current locale when PCRE is compiled. It
857        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
858        characters, are recognized by isspace() and therefore were getting set in
859        these tables, and indeed these tables seem to approximate to ISO 8859. This
860        caused a problem in UTF-8 mode when pcre_study() was used to create a list
861        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
862        which of course cannot start UTF-8 characters. I have changed the code so
863        that only real ASCII characters (less than 128) and the correct starting
864        bytes for UTF-8 encodings are set for characters greater than 127 when in
865        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
866        altogether.)
867    
868    20. Added the /T option to pcretest so as to be able to run tests with non-
869        standard character tables, thus making it possible to include the tests
870        used for 19 above in the standard set of tests.
871    
872    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
873        reference to a subpattern the other side of a comment that contains an
874        opening parenthesis caused either an internal compiling error, or a
875        reference to the wrong subpattern.
876    
877    
878    Version 8.02 19-Mar-2010
879  ------------------------  ------------------------
880    
881  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.
882    
883  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
884      configured.      configured.
885    
886  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
887      original author of that file, following a query about its status.      original author of that file, following a query about its status.
888    
889  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
890      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
891    
892  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
893      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
894      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
895      referenced subpattern not found".      referenced subpattern not found".
896    
897  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
898      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
899      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
900      relevant global functions.      relevant global functions.
901    
902  7.  There were two entries missing in the vectors called coptable and poptable  7.  There were two entries missing in the vectors called coptable and poptable
903      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.      in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
904      I've fixed the data, and added a kludgy way of testing at compile time that      I've fixed the data, and added a kludgy way of testing at compile time that
905      the lengths are correct (equal to the number of opcodes).      the lengths are correct (equal to the number of opcodes).
906    
907  8.  Following on from 7, I added a similar kludge to check the length of the  8.  Following on from 7, I added a similar kludge to check the length of the
908      eint vector in pcreposix.c.      eint vector in pcreposix.c.
909    
910  9.  Error texts for pcre_compile() are held as one long string to avoid too  9.  Error texts for pcre_compile() are held as one long string to avoid too
911      much relocation at load time. To find a text, the string is searched,      much relocation at load time. To find a text, the string is searched,
912      counting zeros. There was no check for running off the end of the string,      counting zeros. There was no check for running off the end of the string,
913      which could happen if a new error number was added without updating the      which could happen if a new error number was added without updating the
914      string.      string.
915    
916  10. \K gave a compile-time error if it appeared in a lookbehind assersion.  10. \K gave a compile-time error if it appeared in a lookbehind assersion.
917    
918  11. \K was not working if it appeared in an atomic group or in a group that  11. \K was not working if it appeared in an atomic group or in a group that
919      was called as a "subroutine", or in an assertion. Perl 5.11 documents that      was called as a "subroutine", or in an assertion. Perl 5.11 documents that
920      \K is "not well defined" if used in an assertion. PCRE now accepts it if      \K is "not well defined" if used in an assertion. PCRE now accepts it if
921      the assertion is positive, but not if it is negative.      the assertion is positive, but not if it is negative.
922    
923  12. Change 11 fortuitously reduced the size of the stack frame used in the  12. Change 11 fortuitously reduced the size of the stack frame used in the
924      "match()" function of pcre_exec.c by one pointer. Forthcoming      "match()" function of pcre_exec.c by one pointer. Forthcoming
925      implementation of support for (*MARK) will need an extra pointer on the      implementation of support for (*MARK) will need an extra pointer on the
926      stack; I have reserved it now, so that the stack frame size does not      stack; I have reserved it now, so that the stack frame size does not
927      decrease.      decrease.
928    
929  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other  13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
930      item in branch that calls a recursion is a subroutine call - as in the      item in branch that calls a recursion is a subroutine call - as in the
931      second branch in the above example - was incorrectly given the compile-      second branch in the above example - was incorrectly given the compile-
932      time error "recursive call could loop indefinitely" because pcre_compile()      time error "recursive call could loop indefinitely" because pcre_compile()
933      was not correctly checking the subroutine for matching a non-empty string.      was not correctly checking the subroutine for matching a non-empty string.
934    
935  14. The checks for overrunning compiling workspace could trigger after an  14. The checks for overrunning compiling workspace could trigger after an
936      overrun had occurred. This is a "should never occur" error, but it can be      overrun had occurred. This is a "should never occur" error, but it can be
937      triggered by pathological patterns such as hundreds of nested parentheses.      triggered by pathological patterns such as hundreds of nested parentheses.
938      The checks now trigger 100 bytes before the end of the workspace.      The checks now trigger 100 bytes before the end of the workspace.
939    
940    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
941    
942    
943  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010

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