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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.0 02 Jul-08  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    
112    Version 8.30 04-February-2012
113    -----------------------------
114    
115    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
116        name is defined in ctype.h.
117    
118    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
119        only in quite long subpatterns.
120    
121    3.  Removed the function pcre_info(), which has been obsolete and deprecated
122        since it was replaced by pcre_fullinfo() in February 2000.
123    
124    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
125        match a (*MARK), and the match failed at the start of the subject, a
126        reference to memory before the start of the subject could occur. This bug
127        was introduced by fix 17 of release 8.21.
128    
129    5.  A reference to an unset group with zero minimum repetition was giving
130        totally wrong answers (in non-JavaScript-compatibility mode). For example,
131        /(another)?(\1?)test/ matched against "hello world test". This bug was
132        introduced in release 8.13.
133    
134    6.  Add support for 16-bit character strings (a large amount of work involving
135        many changes and refactorings).
136    
137    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
138        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
139        from a file.
140    
141    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
142        rounding is not applied in this particular case).
143    
144    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
145        if they appear, or are escaped, in patterns.
146    
147    10. Get rid of a number of -Wunused-but-set-variable warnings.
148    
149    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
150        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
151        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
152        also returns the mark "x". This bug applied to capturing parentheses,
153        non-capturing parentheses, and atomic parentheses. It also applied to some
154        assertions.
155    
156    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
157        information out of configure.ac instead of relying on pcre.h.generic, which
158        is not stored in the repository.
159    
160    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
161        -lreadline.
162    
163    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
164    
165    15. Applied Graycode's patch to put the top-level frame on the stack rather
166        than the heap when not using the stack for recursion. This gives a
167        performance improvement in many cases when recursion is not deep.
168    
169    16. Experimental code added to "pcretest -C" to output the stack frame size.
170    
171    
172    Version 8.21 12-Dec-2011
173    ------------------------
174    
175    1.  Updating the JIT compiler.
176    
177    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
178        are added as well.
179    
180    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
181        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
182        calling _pcre_jit_exec. Some extra comments are added.
183    
184    4.  (*MARK) settings inside atomic groups that do not contain any capturing
185        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
186        was introduced by change 18 for 8.20.
187    
188    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
189        ECMA-262 standard.
190    
191    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
192        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
193        This bug was probably introduced by change 9 of 8.13.
194    
195    7.  While fixing 6 above, I noticed that a number of other items were being
196        incorrectly rejected as "not fixed length". This arose partly because newer
197        opcodes had not been added to the fixed-length checking code. I have (a)
198        corrected the bug and added tests for these items, and (b) arranged for an
199        error to occur if an unknown opcode is encountered while checking for fixed
200        length instead of just assuming "not fixed length". The items that were
201        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
202        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
203        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
204    
205    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
206        being incorrectly compiled and would have given unpredicatble results.
207    
208    9.  A possessively repeated subpattern with minimum repeat count greater than
209        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
210        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
211        the first (A) could occur when it should not.
212    
213    10. Add a cast and remove a redundant test from the code.
214    
215    11. JIT should use pcre_malloc/pcre_free for allocation.
216    
217    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
218        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
219        is anything other than /usr, -L is still shown).
220    
221    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
222    
223    14. Perl does not support \N without a following name in a [] class; PCRE now
224        also gives an error.
225    
226    15. If a forward reference was repeated with an upper limit of around 2000,
227        it caused the error "internal error: overran compiling workspace". The
228        maximum number of forward references (including repeats) was limited by the
229        internal workspace, and dependent on the LINK_SIZE. The code has been
230        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
231        the default depends on LINK_SIZE. There is a new upper limit (for safety)
232        of around 200,000 forward references. While doing this, I also speeded up
233        the filling in of repeated forward references.
234    
235    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
236        incorrectly expecting the subject to contain another "a" after the start.
237    
238    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
239        in the match, the SKIP should be ignored. This was not happening; instead
240        the SKIP was being treated as NOMATCH. For patterns such as
241        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
242        tested.
243    
244    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
245        now much more compatible with Perl, in particular in cases where the result
246        is a non-match for a non-anchored pattern. For example, if
247        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
248        "m", where previously it did not return a name. A side effect of this
249        change is that for partial matches, the last encountered mark name is
250        returned, as for non matches. A number of tests that were previously not
251        Perl-compatible have been moved into the Perl-compatible test files. The
252        refactoring has had the pleasing side effect of removing one argument from
253        the match() function, thus reducing its stack requirements.
254    
255    19. If the /S+ option was used in pcretest to study a pattern using JIT,
256        subsequent uses of /S (without +) incorrectly behaved like /S+.
257    
258    21. Retrieve executable code size support for the JIT compiler and fixing
259        some warnings.
260    
261    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
262        not work when the shorter character appeared right at the end of the
263        subject string.
264    
265    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
266        systems.
267    
268    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
269        output it when the /M option is used in pcretest.
270    
271    25. The CheckMan script was not being included in the distribution. Also, added
272        an explicit "perl" to run Perl scripts from the PrepareRelease script
273        because this is reportedly needed in Windows.
274    
275    26. If study data was being save in a file and studying had not found a set of
276        "starts with" bytes for the pattern, the data written to the file (though
277        never used) was taken from uninitialized memory and so caused valgrind to
278        complain.
279    
280    27. Updated RunTest.bat as provided by Sheri Pierce.
281    
282    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
283    
284    29. Computation of memory usage for the table of capturing group names was
285        giving an unnecessarily large value.
286    
287    
288    Version 8.20 21-Oct-2011
289    ------------------------
290    
291    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
292        a POSIX class. After further experiments with Perl, which convinced me that
293        Perl has bugs and confusions, a closing square bracket is no longer allowed
294        in a POSIX name. This bug also affected patterns with classes that started
295        with full stops.
296    
297    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
298        captured substring, but while checking the failing first alternative,
299        substring 1 is temporarily captured. If the output vector supplied to
300        pcre_exec() was not big enough for this capture, the yield of the function
301        was still zero ("insufficient space for captured substrings"). This cannot
302        be totally fixed without adding another stack variable, which seems a lot
303        of expense for a edge case. However, I have improved the situation in cases
304        such as /(a)(b)x|abc/ matched against "abc", where the return code
305        indicates that fewer than the maximum number of slots in the ovector have
306        been set.
307    
308    3.  Related to (2) above: when there are more back references in a pattern than
309        slots in the output vector, pcre_exec() uses temporary memory during
310        matching, and copies in the captures as far as possible afterwards. It was
311        using the entire output vector, but this conflicts with the specification
312        that only 2/3 is used for passing back captured substrings. Now it uses
313        only the first 2/3, for compatibility. This is, of course, another edge
314        case.
315    
316    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
317        main code base, and can be used by building with --enable-jit. When this is
318        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
319        runtime --no-jit option is given.
320    
321    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
322        ovector, the return from the function was zero, implying that there were
323        other matches that did not fit. The correct "exactly full" value is now
324        returned.
325    
326    6.  If a subpattern that was called recursively or as a subroutine contained
327        (*PRUNE) or any other control that caused it to give a non-standard return,
328        invalid errors such as "Error -26 (nested recursion at the same subject
329        position)" or even infinite loops could occur.
330    
331    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
332        computing the minimum length on reaching *ACCEPT, and so ended up with the
333        wrong value of 1 rather than 0. Further investigation indicates that
334        computing a minimum subject length in the presence of *ACCEPT is difficult
335        (think back references, subroutine calls), and so I have changed the code
336        so that no minimum is registered for a pattern that contains *ACCEPT.
337    
338    8.  If (*THEN) was present in the first (true) branch of a conditional group,
339        it was not handled as intended. [But see 16 below.]
340    
341    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
342        Sheri Pierce.
343    
344    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
345        the first byte in a match must be "a".
346    
347    11. Change 17 for 8.13 increased the recursion depth for patterns like
348        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
349        pattern contains any instances of (*THEN). If it does not, the old
350        optimizations are restored. It would be nice to do this on a per-group
351        basis, but at the moment that is not feasible.
352    
353    12. In some environments, the output of pcretest -C is CRLF terminated. This
354        broke RunTest's code that checks for the link size. A single white space
355        character after the value is now allowed for.
356    
357    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
358        For "fr", it uses the Windows-specific input and output files.
359    
360    14. If (*THEN) appeared in a group that was called recursively or as a
361        subroutine, it did not work as intended. [But see next item.]
362    
363    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
364        pattern fragments (but not containing any | characters). If A and B are
365        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
366        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
367        D. In other words, Perl considers parentheses that do not contain any |
368        characters to be part of a surrounding alternative, whereas PCRE was
369        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
370        differently. PCRE now behaves in the same way as Perl, except in the case
371        of subroutine/recursion calls such as (?1) which have in any case always
372        been different (but PCRE had them first :-).
373    
374    16. Related to 15 above: Perl does not treat the | in a conditional group as
375        creating alternatives. Such a group is treated in the same way as an
376        ordinary group without any | characters when processing (*THEN). PCRE has
377        been changed to match Perl's behaviour.
378    
379    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
380        RunGrepTest script failed.
381    
382    18. Change 22 for version 13 caused atomic groups to use more stack. This is
383        inevitable for groups that contain captures, but it can lead to a lot of
384        stack use in large patterns. The old behaviour has been restored for atomic
385        groups that do not contain any capturing parentheses.
386    
387    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
388        suppress the check for a minimum subject length at run time. (If it was
389        given to pcre_exec() or pcre_dfa_exec() it did work.)
390    
391    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
392        fail to work when decoding hex characters in data strings in EBCDIC
393        environments.
394    
395    21. It appears that in at least one Mac OS environment, the isxdigit() function
396        is implemented as a macro that evaluates to its argument more than once,
397        contravening the C 90 Standard (I haven't checked a later standard). There
398        was an instance in pcretest which caused it to go wrong when processing
399        \x{...} escapes in subject strings. The has been rewritten to avoid using
400        things like p++ in the argument of isxdigit().
401    
402    
403    Version 8.13 16-Aug-2011
404    ------------------------
405    
406    1.  The Unicode data tables have been updated to Unicode 6.0.0.
407    
408    2.  Two minor typos in pcre_internal.h have been fixed.
409    
410    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
411        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
412        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
413    
414    4.  There were a number of related bugs in the code for matching backrefences
415        caselessly in UTF-8 mode when codes for the characters concerned were
416        different numbers of bytes. For example, U+023A and U+2C65 are an upper
417        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
418        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
419        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
420        2-byte code at the end of the subject (it thought there wasn't enough data
421        left).
422    
423    5.  Comprehensive information about what went wrong is now returned by
424        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
425        as the output vector has at least 2 elements. The offset of the start of
426        the failing character and a reason code are placed in the vector.
427    
428    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
429        now returned is for the first byte of the failing character, instead of the
430        last byte inspected. This is an incompatible change, but I hope it is small
431        enough not to be a problem. It makes the returned offset consistent with
432        pcre_exec() and pcre_dfa_exec().
433    
434    7.  pcretest now gives a text phrase as well as the error number when
435        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
436        failure, the offset and reason code are output.
437    
438    8.  When \R was used with a maximizing quantifier it failed to skip backwards
439        over a \r\n pair if the subsequent match failed. Instead, it just skipped
440        back over a single character (\n). This seems wrong (because it treated the
441        two characters as a single entity when going forwards), conflicts with the
442        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
443        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
444        has been changed.
445    
446    9.  Some internal refactoring has changed the processing so that the handling
447        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
448        time (the PCRE_DOTALL option was changed this way some time ago: version
449        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
450        which was always a bit of a fudge. It also means that there is one less
451        argument for the match() function, which reduces its stack requirements
452        slightly. This change also fixes an incompatibility with Perl: the pattern
453        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
454    
455    10. More internal refactoring has drastically reduced the number of recursive
456        calls to match() for possessively repeated groups such as (abc)++ when
457        using pcre_exec().
458    
459    11. While implementing 10, a number of bugs in the handling of groups were
460        discovered and fixed:
461    
462        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
463        (a|)*(?1) gave a compile-time internal error.
464        ((a|)+)+  did not notice that the outer group could match an empty string.
465        (^a|^)+   was not marked as anchored.
466        (.*a|.*)+ was not marked as matching at start or after a newline.
467    
468    12. Yet more internal refactoring has removed another argument from the match()
469        function. Special calls to this function are now indicated by setting a
470        value in a variable in the "match data" data block.
471    
472    13. Be more explicit in pcre_study() instead of relying on "default" for
473        opcodes that mean there is no starting character; this means that when new
474        ones are added and accidentally left out of pcre_study(), testing should
475        pick them up.
476    
477    14. The -s option of pcretest has been documented for ages as being an old
478        synonym of -m (show memory usage). I have changed it to mean "force study
479        for every regex", that is, assume /S for every regex. This is similar to -i
480        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
481        using it. It makes it easier to run collections of tests with and without
482        study enabled, and thereby test pcre_study() more easily. All the standard
483        tests are now run with and without -s (but some patterns can be marked as
484        "never study" - see 20 below).
485    
486    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
487        restoration of the capturing data to the outer values was not happening
488        correctly.
489    
490    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
491        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
492        pattern had matched an empty string, and so incorrectly returned a no
493        match.
494    
495    17. There was optimizing code for the last branch of non-capturing parentheses,
496        and also for the obeyed branch of a conditional subexpression, which used
497        tail recursion to cut down on stack usage. Unfortunately, now that there is
498        the possibility of (*THEN) occurring in these branches, tail recursion is
499        no longer possible because the return has to be checked for (*THEN). These
500        two optimizations have therefore been removed. [But see 8.20/11 above.]
501    
502    18. If a pattern containing \R was studied, it was assumed that \R always
503        matched two bytes, thus causing the minimum subject length to be
504        incorrectly computed because \R can also match just one byte.
505    
506    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
507        was incorrectly computed.
508    
509    20. If /S is present twice on a test pattern in pcretest input, it now
510        *disables* studying, thereby overriding the use of -s on the command line
511        (see 14 above). This is necessary for one or two tests to keep the output
512        identical in both cases.
513    
514    21. When (*ACCEPT) was used in an assertion that matched an empty string and
515        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
516    
517    22. When an atomic group that contained a capturing parenthesis was
518        successfully matched, but the branch in which it appeared failed, the
519        capturing was not being forgotten if a higher numbered group was later
520        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
521        group 1 to "a", when in fact it should be unset. This applied to multi-
522        branched capturing and non-capturing groups, repeated or not, and also to
523        positive assertions (capturing in negative assertions does not happen
524        in PCRE) and also to nested atomic groups.
525    
526    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
527        subject after a captured substring, to make it easier to tell which of a
528        number of identical substrings has been captured.
529    
530    24. The way atomic groups are processed by pcre_exec() has been changed so that
531        if they are repeated, backtracking one repetition now resets captured
532        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
533        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
534        "aaa". Previously, it would have been "a". As part of this code
535        refactoring, the way recursive calls are handled has also been changed.
536    
537    25. If an assertion condition captured any substrings, they were not passed
538        back unless some other capturing happened later. For example, if
539        (?(?=(a))a) was matched against "a", no capturing was returned.
540    
541    26. When studying a pattern that contained subroutine calls or assertions,
542        the code for finding the minimum length of a possible match was handling
543        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
544        group 1 called group 2 while simultaneously a separate group 2 called group
545        1). A stack overflow occurred in this case. I have fixed this by limiting
546        the recursion depth to 10.
547    
548    27. Updated RunTest.bat in the distribution to the version supplied by Tom
549        Fortmann. This supports explicit test numbers on the command line, and has
550        argument validation and error reporting.
551    
552    28. An instance of \X with an unlimited repeat could fail if at any point the
553        first character it looked at was a mark character.
554    
555    29. Some minor code refactoring concerning Unicode properties and scripts
556        should reduce the stack requirement of match() slightly.
557    
558    30. Added the '=' option to pcretest to check the setting of unused capturing
559        slots at the end of the pattern, which are documented as being -1, but are
560        not included in the return count.
561    
562    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
563        compiled something random. Now it gives a compile-time error (as does
564        Perl).
565    
566    32. A *MARK encountered during the processing of a positive assertion is now
567        recorded and passed back (compatible with Perl).
568    
569    33. If --only-matching or --colour was set on a pcregrep call whose pattern
570        had alternative anchored branches, the search for a second match in a line
571        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
572        matched the line "0102" twice. The same bug affected patterns that started
573        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
574        twice.
575    
576    34. Previously, PCRE did not allow quantification of assertions. However, Perl
577        does, and because of capturing effects, quantifying parenthesized
578        assertions may at times be useful. Quantifiers are now allowed for
579        parenthesized assertions.
580    
581    35. A minor code tidy in pcre_compile() when checking options for \R usage.
582    
583    36. \g was being checked for fancy things in a character class, when it should
584        just be a literal "g".
585    
586    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
587        appearance of a nested POSIX class supersedes an apparent external class.
588        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
589        unescaped square brackets may also appear as part of class names. For
590        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
591        more like Perl. (But see 8.20/1 above.)
592    
593    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
594        was because it thought it was \N{name}, which is not supported).
595    
596    39. Add minix to OS list not supporting the -S option in pcretest.
597    
598    40. PCRE tries to detect cases of infinite recursion at compile time, but it
599        cannot analyze patterns in sufficient detail to catch mutual recursions
600        such as ((?1))((?2)). There is now a runtime test that gives an error if a
601        subgroup is called recursively as a subpattern for a second time at the
602        same position in the subject string. In previous releases this might have
603        been caught by the recursion limit, or it might have run out of stack.
604    
605    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
606        happen only once. PCRE was, however incorrectly giving a compile time error
607        "recursive call could loop indefinitely" because it cannot analyze the
608        pattern in sufficient detail. The compile time test no longer happens when
609        PCRE is compiling a conditional subpattern, but actual runaway loops are
610        now caught at runtime (see 40 above).
611    
612    42. It seems that Perl allows any characters other than a closing parenthesis
613        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
614        has been changed to be the same.
615    
616    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
617        as not to get warnings when autogen.sh is called. Also changed
618        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
619    
620    44. To help people who use pcregrep to scan files containing exceedingly long
621        lines, the following changes have been made:
622    
623        (a) The default value of the buffer size parameter has been increased from
624            8K to 20K. (The actual buffer used is three times this size.)
625    
626        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
627            PCRE is built.
628    
629        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
630            to be set at run time.
631    
632        (d) Numerical values in pcregrep options can be followed by K or M, for
633            example --buffer-size=50K.
634    
635        (e) If a line being scanned overflows pcregrep's buffer, an error is now
636            given and the return code is set to 2.
637    
638    45. Add a pointer to the latest mark to the callout data block.
639    
640    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
641        partial match of an empty string instead of no match. This was specific to
642        the use of ".".
643    
644    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
645        complete match instead of a partial match. This bug was dependent on both
646        the PCRE_UTF8 and PCRE_DOTALL options being set.
647    
648    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
649        starting byte set, because \b was not being ignored.
650    
651    
652    Version 8.12 15-Jan-2011
653    ------------------------
654    
655    1.  Fixed some typos in the markup of the man pages, and wrote a script that
656        checks for such things as part of the documentation building process.
657    
658    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
659        --match-limit and --recursion-limit options (added for 8.11). In
660        particular, this made one of the standard tests fail. (The integer value
661        went into the wrong half of a long int.)
662    
663    3.  If the --colour option was given to pcregrep with -v (invert match), it
664        did strange things, either producing crazy output, or crashing. It should,
665        of course, ignore a request for colour when reporting lines that do not
666        match.
667    
668    4.  Another pcregrep bug caused similar problems if --colour was specified with
669        -M (multiline) and the pattern match finished with a line ending.
670    
671    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
672        matched in multiline mode, the following line was shown as part of the
673        match. This seems wrong, so I have changed it.
674    
675    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
676        the check for further matches in the same line (so they could be coloured)
677        to overrun the end of the current line. If another match was found, it was
678        incorrectly shown (and then shown again when found in the next line).
679    
680    7.  If pcregrep was compiled under Windows, there was a reference to the
681        function pcregrep_exit() before it was defined. I am assuming this was
682        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
683        reported by a user. I've moved the definition above the reference.
684    
685    
686    Version 8.11 10-Dec-2010
687    ------------------------
688    
689    1.  (*THEN) was not working properly if there were untried alternatives prior
690        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
691        backtracked to try for "b" instead of moving to the next alternative branch
692        at the same level (in this case, to look for "c"). The Perl documentation
693        is clear that when (*THEN) is backtracked onto, it goes to the "next
694        alternative in the innermost enclosing group".
695    
696    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
697        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
698        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
699        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
700        (*THEN).
701    
702    3.  If \s appeared in a character class, it removed the VT character from
703        the class, even if it had been included by some previous item, for example
704        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
705        of \s, but is part of the POSIX "space" class.)
706    
707    4.  A partial match never returns an empty string (because you can always
708        match an empty string at the end of the subject); however the checking for
709        an empty string was starting at the "start of match" point. This has been
710        changed to the "earliest inspected character" point, because the returned
711        data for a partial match starts at this character. This means that, for
712        example, /(?<=abc)def/ gives a partial match for the subject "abc"
713        (previously it gave "no match").
714    
715    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
716        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
717        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
718        has an implication that the given string is incomplete (because a partial
719        match is preferred over a full match). For this reason, these items now
720        give a partial match in this situation. [Aside: previously, the one case
721        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
722        match rather than a full match, which was wrong by the old rules, but is
723        now correct.]
724    
725    6.  There was a bug in the handling of #-introduced comments, recognized when
726        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
727        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
728        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
729        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
730        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
731        places in pcre_compile().
732    
733    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
734        comments when looking ahead for named forward references to subpatterns,
735        the only newline sequence it recognized was NL. It now handles newlines
736        according to the set newline convention.
737    
738    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
739        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
740        cater for a lack of strerror(). These oversights have been fixed.
741    
742    9.  Added --match-limit and --recursion-limit to pcregrep.
743    
744    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
745    
746    11. When the -o option was used, pcregrep was setting a return code of 1, even
747        when matches were found, and --line-buffered was not being honoured.
748    
749    12. Added an optional parentheses number to the -o and --only-matching options
750        of pcregrep.
751    
752    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
753        can match an empty string. The code to do it in pcretest and pcredemo
754        needed fixing:
755    
756        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
757            only one byte after an empty string match just before CRLF (this case
758            just got forgotten; "any" and "anycrlf" were OK).
759    
760        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
761            mode when an empty string match preceded an ASCII character followed by
762            a non-ASCII character. (The code for advancing by one character rather
763            than one byte was nonsense.)
764    
765        (c) The pcredemo.c sample program did not have any code at all to handle
766            the cases when CRLF is a valid newline sequence.
767    
768    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
769        as a starting offset was within the subject string. There is now a new
770        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
771        negative or greater than the length of the string. In order to test this,
772        pcretest is extended to allow the setting of negative starting offsets.
773    
774    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
775        starting offset points to the beginning of a UTF-8 character was
776        unnecessarily clumsy. I tidied it up.
777    
778    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
779        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
780    
781    17. Nobody had reported that the --include_dir option, which was added in
782        release 7.7 should have been called --include-dir (hyphen, not underscore)
783        for compatibility with GNU grep. I have changed it to --include-dir, but
784        left --include_dir as an undocumented synonym, and the same for
785        --exclude-dir, though that is not available in GNU grep, at least as of
786        release 2.5.4.
787    
788    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
789        characters from a string of bytes) have been redefined so as not to use
790        loops, in order to improve performance in some environments. At the same
791        time, I abstracted some of the common code into auxiliary macros to save
792        repetition (this should not affect the compiled code).
793    
794    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
795        compile-time error is now given if \c is not followed by an ASCII
796        character, that is, a byte less than 128. (In EBCDIC mode, the code is
797        different, and any byte value is allowed.)
798    
799    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
800        START_OPTIMIZE option, which is now allowed at compile time - but just
801        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
802        to pcregrep and other applications that have no direct access to PCRE
803        options. The new /Y option in pcretest sets this option when calling
804        pcre_compile().
805    
806    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
807        back references. Groups containing recursive back references were forced to
808        be atomic by that change, but in the case of named groups, the amount of
809        memory required was incorrectly computed, leading to "Failed: internal
810        error: code overflow". This has been fixed.
811    
812    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
813        pcretest.c, to avoid build problems in some Borland environments.
814    
815    
816    Version 8.10 25-Jun-2010
817    ------------------------
818    
819    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
820        THEN.
821    
822    2.  (*ACCEPT) was not working when inside an atomic group.
823    
824    3.  Inside a character class, \B is treated as a literal by default, but
825        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
826        causes the error). The code is unchanged, but I tidied the documentation.
827    
828    4.  Inside a character class, PCRE always treated \R and \X as literals,
829        whereas Perl faults them if its -w option is set. I have changed PCRE so
830        that it faults them when PCRE_EXTRA is set.
831    
832    5.  Added support for \N, which always matches any character other than
833        newline. (It is the same as "." when PCRE_DOTALL is not set.)
834    
835    6.  When compiling pcregrep with newer versions of gcc which may have
836        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
837        declared with attribute warn_unused_result" were given. Just casting the
838        result to (void) does not stop the warnings; a more elaborate fudge is
839        needed. I've used a macro to implement this.
840    
841    7.  Minor change to pcretest.c to avoid a compiler warning.
842    
843    8.  Added four artifical Unicode properties to help with an option to make
844        \s etc use properties (see next item). The new properties are: Xan
845        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
846    
847    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
848        use Unicode properties. (*UCP) at the start of a pattern can be used to set
849        this option. Modified pcretest to add /W to test this facility. Added
850        REG_UCP to make it available via the POSIX interface.
851    
852    10. Added --line-buffered to pcregrep.
853    
854    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
855        studied, and the match started with a letter with a code point greater than
856        127 whose first byte was different to the first byte of the other case of
857        the letter, the other case of this starting letter was not recognized
858        (#976).
859    
860    12. If a pattern that was studied started with a repeated Unicode property
861        test, for example, \p{Nd}+, there was the theoretical possibility of
862        setting up an incorrect bitmap of starting bytes, but fortunately it could
863        not have actually happened in practice until change 8 above was made (it
864        added property types that matched character-matching opcodes).
865    
866    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
867        possible starting bytes for non-anchored patterns.
868    
869    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
870        \R, and also a number of cases that involve Unicode properties, both
871        explicit and implicit when PCRE_UCP is set.
872    
873    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
874        input, it could crash or give wrong results if characters with values
875        greater than 0xc0 were present in the subject string. (Detail: it assumed
876        UTF-8 input when processing these items.)
877    
878    16. Added a lot of (int) casts to avoid compiler warnings in systems where
879        size_t is 64-bit (#991).
880    
881    17. Added a check for running out of memory when PCRE is compiled with
882        --disable-stack-for-recursion (#990).
883    
884    18. If the last data line in a file for pcretest does not have a newline on
885        the end, a newline was missing in the output.
886    
887    19. The default pcre_chartables.c file recognizes only ASCII characters (values
888        less than 128) in its various bitmaps. However, there is a facility for
889        generating tables according to the current locale when PCRE is compiled. It
890        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
891        characters, are recognized by isspace() and therefore were getting set in
892        these tables, and indeed these tables seem to approximate to ISO 8859. This
893        caused a problem in UTF-8 mode when pcre_study() was used to create a list
894        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
895        which of course cannot start UTF-8 characters. I have changed the code so
896        that only real ASCII characters (less than 128) and the correct starting
897        bytes for UTF-8 encodings are set for characters greater than 127 when in
898        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
899        altogether.)
900    
901    20. Added the /T option to pcretest so as to be able to run tests with non-
902        standard character tables, thus making it possible to include the tests
903        used for 19 above in the standard set of tests.
904    
905    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
906        reference to a subpattern the other side of a comment that contains an
907        opening parenthesis caused either an internal compiling error, or a
908        reference to the wrong subpattern.
909    
910    
911    Version 8.02 19-Mar-2010
912    ------------------------
913    
914    1.  The Unicode data tables have been updated to Unicode 5.2.0.
915    
916    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
917        configured.
918    
919    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
920        original author of that file, following a query about its status.
921    
922    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
923        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
924    
925    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
926        quantifier applied to a forward-referencing subroutine call, could compile
927        incorrect code or give the error "internal error: previously-checked
928        referenced subpattern not found".
929    
930    6.  Both MS Visual Studio and Symbian OS have problems with initializing
931        variables to point to external functions. For these systems, therefore,
932        pcre_malloc etc. are now initialized to local functions that call the
933        relevant global functions.
934    
935    7.  There were two entries missing in the vectors called coptable and poptable
936        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
937        I've fixed the data, and added a kludgy way of testing at compile time that
938        the lengths are correct (equal to the number of opcodes).
939    
940    8.  Following on from 7, I added a similar kludge to check the length of the
941        eint vector in pcreposix.c.
942    
943    9.  Error texts for pcre_compile() are held as one long string to avoid too
944        much relocation at load time. To find a text, the string is searched,
945        counting zeros. There was no check for running off the end of the string,
946        which could happen if a new error number was added without updating the
947        string.
948    
949    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
950    
951    11. \K was not working if it appeared in an atomic group or in a group that
952        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
953        \K is "not well defined" if used in an assertion. PCRE now accepts it if
954        the assertion is positive, but not if it is negative.
955    
956    12. Change 11 fortuitously reduced the size of the stack frame used in the
957        "match()" function of pcre_exec.c by one pointer. Forthcoming
958        implementation of support for (*MARK) will need an extra pointer on the
959        stack; I have reserved it now, so that the stack frame size does not
960        decrease.
961    
962    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
963        item in branch that calls a recursion is a subroutine call - as in the
964        second branch in the above example - was incorrectly given the compile-
965        time error "recursive call could loop indefinitely" because pcre_compile()
966        was not correctly checking the subroutine for matching a non-empty string.
967    
968    14. The checks for overrunning compiling workspace could trigger after an
969        overrun had occurred. This is a "should never occur" error, but it can be
970        triggered by pathological patterns such as hundreds of nested parentheses.
971        The checks now trigger 100 bytes before the end of the workspace.
972    
973    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
974    
975    
976    Version 8.01 19-Jan-2010
977    ------------------------
978    
979    1.  If a pattern contained a conditional subpattern with only one branch (in
980        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
981        computed the wrong minimum data length (which is of course zero for such
982        subpatterns). This could cause incorrect "no match" results.
983    
984    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
985        the pattern is reset in the first branch, pcre_compile() failed with
986        "internal error: code overflow at offset...". This happened only when
987        the reset was to the original external option setting. (An optimization
988        abstracts leading options settings into an external setting, which was the
989        cause of this.)
990    
991    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
992        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
993        assertion pattern did not match (meaning that the assertion was true), it
994        was incorrectly treated as false if the SKIP had been reached during the
995        matching. This also applied to assertions used as conditions.
996    
997    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
998        assertion subpattern, including such a pattern used as a condition,
999        unpredictable results occurred, instead of the error return
1000        PCRE_ERROR_DFA_UITEM.
1001    
1002    5.  The C++ GlobalReplace function was not working like Perl for the special
1003        situation when an empty string is matched. It now does the fancy magic
1004        stuff that is necessary.
1005    
1006    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1007        removed. (These were left over from very, very early versions of PCRE.)
1008    
1009    7.  Some cosmetic changes to the code to make life easier when compiling it
1010        as part of something else:
1011    
1012        (a) Change DEBUG to PCRE_DEBUG.
1013    
1014        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1015            called "current" as "current_branch", to prevent a collision with the
1016            Linux macro when compiled as a kernel module.
1017    
1018        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1019            prevent a collision with the Linux macro when compiled as a kernel
1020            module.
1021    
1022    8.  In pcre_compile() there are some checks for integer overflows that used to
1023        cast potentially large values to (double). This has been changed to that
1024        when building, a check for int64_t is made, and if it is found, it is used
1025        instead, thus avoiding the use of floating point arithmetic. (There is no
1026        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1027        double.
1028    
1029    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1030        2005 (difference between two addresses compared to an unsigned value).
1031    
1032    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1033        custom one, because of the following reported problem in Windows:
1034    
1035          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1036              under Win32.
1037          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1038              therefore missing the function definition.
1039          - The compiler thus generates a "C" signature for the test function.
1040          - The linker fails to find the "C" function.
1041          - PCRE fails to configure if asked to do so against libbz2.
1042    
1043    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1044        messages were output:
1045    
1046          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1047          rerunning libtoolize, to keep the correct libtool macros in-tree.
1048          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1049    
1050        I have done both of these things.
1051    
1052    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1053        most of the time, it *can* run out if it is given a pattern that contains a
1054        runaway infinite recursion. I updated the discussion in the pcrestack man
1055        page.
1056    
1057    13. Now that we have gone to the x.xx style of version numbers, the minor
1058        version may start with zero. Using 08 or 09 is a bad idea because users
1059        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1060        interpreted as invalid octal numbers. I've updated the previous comment in
1061        configure.ac, and also added a check that gives an error if 08 or 09 are
1062        used.
1063    
1064    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1065        causing partial matching to fail when the end of the subject matched \W
1066        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1067    
1068    15. There were some discrepancies between the declarations in pcre_internal.h
1069        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1070        their definitions. The declarations used "const uschar *" and the
1071        definitions used USPTR. Even though USPTR is normally defined as "const
1072        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1073        reported that: "This difference in casting confuses some C++ compilers, for
1074        example, SunCC recognizes above declarations as different functions and
1075        generates broken code for hbpcre." I have changed the declarations to use
1076        USPTR.
1077    
1078    16. GNU libtool is named differently on some systems. The autogen.sh script now
1079        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1080        (FreeBSD).
1081    
1082    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1083        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1084        comment: "Figure out how to create a longlong from a string: strtoll and
1085        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1086        instance, but it only takes 2 args instead of 3!"
1087    
1088    18. A subtle bug concerned with back references has been fixed by a change of
1089        specification, with a corresponding code fix. A pattern such as
1090        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1091        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1092        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1093        same bug. Such groups have to be quantified to be useful, or contained
1094        inside another quantified group. (If there's no repetition, the reference
1095        can never match.) The problem arises because, having left the group and
1096        moved on to the rest of the pattern, a later failure that backtracks into
1097        the group uses the captured value from the final iteration of the group
1098        rather than the correct earlier one. I have fixed this in PCRE by forcing
1099        any group that contains a reference to itself to be an atomic group; that
1100        is, there cannot be any backtracking into it once it has completed. This is
1101        similar to recursive and subroutine calls.
1102    
1103    
1104    Version 8.00 19-Oct-09
1105    ----------------------
1106    
1107    1.  The table for translating pcre_compile() error codes into POSIX error codes
1108        was out-of-date, and there was no check on the pcre_compile() error code
1109        being within the table. This could lead to an OK return being given in
1110        error.
1111    
1112    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1113        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1114        in a Windows environment.
1115    
1116    3.  The pcregrep --count option prints the count for each file even when it is
1117        zero, as does GNU grep. However, pcregrep was also printing all files when
1118        --files-with-matches was added. Now, when both options are given, it prints
1119        counts only for those files that have at least one match. (GNU grep just
1120        prints the file name in this circumstance, but including the count seems
1121        more useful - otherwise, why use --count?) Also ensured that the
1122        combination -clh just lists non-zero counts, with no names.
1123    
1124    4.  The long form of the pcregrep -F option was incorrectly implemented as
1125        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1126        but it seems right to fix it, and I didn't think it was worth preserving
1127        the old behaviour.
1128    
1129    5.  The command line items --regex=pattern and --regexp=pattern were not
1130        recognized by pcregrep, which required --regex pattern or --regexp pattern
1131        (with a space rather than an '='). The man page documented the '=' forms,
1132        which are compatible with GNU grep; these now work.
1133    
1134    6.  No libpcreposix.pc file was created for pkg-config; there was just
1135        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1136    
1137    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1138        when UCP support is not needed, by modifying the Python script that
1139        generates it from Unicode data files. This should not matter if the module
1140        is correctly used as a library, but I received one complaint about 50K of
1141        unwanted data. My guess is that the person linked everything into his
1142        program rather than using a library. Anyway, it does no harm.
1143    
1144    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1145        was a minimum greater than 1 for a wide character in a possessive
1146        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1147        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1148        character. Chaos in the form of incorrect output or a compiling loop could
1149        result.
1150    
1151    9.  The restrictions on what a pattern can contain when partial matching is
1152        requested for pcre_exec() have been removed. All patterns can now be
1153        partially matched by this function. In addition, if there are at least two
1154        slots in the offset vector, the offset of the earliest inspected character
1155        for the match and the offset of the end of the subject are set in them when
1156        PCRE_ERROR_PARTIAL is returned.
1157    
1158    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1159        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1160        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1161        and may be more useful for multi-segment matching.
1162    
1163    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1164        used to be given if ever the end of the subject was reached; now it is
1165        given only if matching could not proceed because another character was
1166        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1167        string "Z", which now yields "no match" instead of "partial match". In the
1168        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1169        final character ended with (*FAIL).
1170    
1171    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1172        if the pattern had a "must contain" character that was already found in the
1173        earlier partial match, unless partial matching was again requested. For
1174        example, with the pattern /dog.(body)?/, the "must contain" character is
1175        "g". If the first part-match was for the string "dog", restarting with
1176        "sbody" failed. This bug has been fixed.
1177    
1178    13. The string returned by pcre_dfa_exec() after a partial match has been
1179        changed so that it starts at the first inspected character rather than the
1180        first character of the match. This makes a difference only if the pattern
1181        starts with a lookbehind assertion or \b or \B (\K is not supported by
1182        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1183        matching functions compatible, and I think it's the right thing to do.
1184    
1185    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1186        so that the demonstration program is easily available in environments where
1187        PCRE has not been installed from source.
1188    
1189    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1190        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1191        library.
1192    
1193    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1194        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1195        is not the first non-POSIX option to be added. Clearly some people find
1196        these options useful.
1197    
1198    17. If a caller to the POSIX matching function regexec() passes a non-zero
1199        value for nmatch with a NULL value for pmatch, the value of
1200        nmatch is forced to zero.
1201    
1202    18. RunGrepTest did not have a test for the availability of the -u option of
1203        the diff command, as RunTest does. It now checks in the same way as
1204        RunTest, and also checks for the -b option.
1205    
1206    19. If an odd number of negated classes containing just a single character
1207        interposed, within parentheses, between a forward reference to a named
1208        subpattern and the definition of the subpattern, compilation crashed with
1209        an internal error, complaining that it could not find the referenced
1210        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1211        [The bug was that it was starting one character too far in when skipping
1212        over the character class, thus treating the ] as data rather than
1213        terminating the class. This meant it could skip too much.]
1214    
1215    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1216        /g option in pcretest when the pattern contains \K, which makes it possible
1217        to have an empty string match not at the start, even when the pattern is
1218        anchored. Updated pcretest and pcredemo to use this option.
1219    
1220    21. If the maximum number of capturing subpatterns in a recursion was greater
1221        than the maximum at the outer level, the higher number was returned, but
1222        with unset values at the outer level. The correct (outer level) value is
1223        now given.
1224    
1225    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1226        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1227        make it do so. The string so far is captured, making this feature
1228        compatible with Perl.
1229    
1230    23. The tests have been re-organized, adding tests 11 and 12, to make it
1231        possible to check the Perl 5.10 features against Perl 5.10.
1232    
1233    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1234        pattern matches a fixed length string. PCRE did not allow this; now it
1235        does. Neither allows recursion.
1236    
1237    25. I finally figured out how to implement a request to provide the minimum
1238        length of subject string that was needed in order to match a given pattern.
1239        (It was back references and recursion that I had previously got hung up
1240        on.) This code has now been added to pcre_study(); it finds a lower bound
1241        to the length of subject needed. It is not necessarily the greatest lower
1242        bound, but using it to avoid searching strings that are too short does give
1243        some useful speed-ups. The value is available to calling programs via
1244        pcre_fullinfo().
1245    
1246    26. While implementing 25, I discovered to my embarrassment that pcretest had
1247        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1248        study optimizations had never been tested with that matching function.
1249        Oops. What is worse, even when it was passed study data, there was a bug in
1250        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1251        were also very few tests of studied patterns with pcre_dfa_exec().
1252    
1253    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1254        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1255        on the other side of the coin, they are no longer allowed to have different
1256        names, because these cannot be distinguished in PCRE, and this has caused
1257        confusion. (This is a difference from Perl.)
1258    
1259    28. When duplicate subpattern names are present (necessarily with different
1260        numbers, as required by 27 above), and a test is made by name in a
1261        conditional pattern, either for a subpattern having been matched, or for
1262        recursion in such a pattern, all the associated numbered subpatterns are
1263        tested, and the overall condition is true if the condition is true for any
1264        one of them. This is the way Perl works, and is also more like the way
1265        testing by number works.
1266    
1267    
1268    Version 7.9 11-Apr-09
1269    ---------------------
1270    
1271    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1272        (pcretest), all targets were linked against these libraries. This included
1273        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1274        libraries. This caused unwanted dependencies to be created. This problem
1275        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1276        pcretest is linked with readline.
1277    
1278    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1279        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1280        moved outside it again, because FALSE and TRUE are already defined in AIX,
1281        but BOOL is not.
1282    
1283    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1284        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1285    
1286    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1287        hyphens) following file names and line numbers when outputting matching
1288        lines. This is not true; no spaces are inserted. I have also clarified the
1289        wording for the --colour (or --color) option.
1290    
1291    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1292        was not coloured; this is different to GNU grep, so I have changed it to be
1293        the same.
1294    
1295    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1296        each matching line was coloured. Now it goes on to look for further matches
1297        of any of the test patterns, which is the same behaviour as GNU grep.
1298    
1299    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1300        doesn't make sense to accept an empty string match in pcregrep, so I have
1301        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1302        seems to be how GNU grep behaves.
1303    
1304    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1305        start or after a newline", because the conditional assertion was not being
1306        correctly handled. The rule now is that both the assertion and what follows
1307        in the first alternative must satisfy the test.
1308    
1309    9.  If auto-callout was enabled in a pattern with a conditional group whose
1310        condition was an assertion, PCRE could crash during matching, both with
1311        pcre_exec() and pcre_dfa_exec().
1312    
1313    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1314        used for matching.
1315    
1316    11. Unicode property support in character classes was not working for
1317        characters (bytes) greater than 127 when not in UTF-8 mode.
1318    
1319    12. Added the -M command line option to pcretest.
1320    
1321    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1322    
1323    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1324    
1325    16. Added comments and documentation about mis-use of no_arg in the C++
1326        wrapper.
1327    
1328    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1329        from Martin Jerabek that uses macro names for all relevant character and
1330        string constants.
1331    
1332    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1333        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1334        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1335        these, but not everybody uses configure.
1336    
1337    19. A conditional group that had only one branch was not being correctly
1338        recognized as an item that could match an empty string. This meant that an
1339        enclosing group might also not be so recognized, causing infinite looping
1340        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1341        with the subject "ab", where knowledge that the repeated group can match
1342        nothing is needed in order to break the loop.
1343    
1344    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1345        exec(), but without supplying a callout function, matching went wrong.
1346    
1347    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1348        leak if the size of the offset vector was greater than 30. When the vector
1349        is smaller, the saved offsets during recursion go onto a local stack
1350        vector, but for larger vectors malloc() is used. It was failing to free
1351        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1352        error, in fact).
1353    
1354    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1355        heapframe that is used only when UTF-8 support is enabled. This caused no
1356        problem, but was untidy.
1357    
1358    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1359        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1360        included within another project.
1361    
1362    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1363        slightly modified by me:
1364    
1365          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1366              not building pcregrep.
1367    
1368          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1369              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1370    
1371    25. Forward references, both numeric and by name, in patterns that made use of
1372        duplicate group numbers, could behave incorrectly or give incorrect errors,
1373        because when scanning forward to find the reference group, PCRE was not
1374        taking into account the duplicate group numbers. A pattern such as
1375        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1376    
1377    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1378        the feature of a custom pointer more persuasive (as requested by a user).
1379    
1380    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1381        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1382        pre-defined.
1383    
1384    28. Added support for (*UTF8) at the start of a pattern.
1385    
1386    29. Arrange for flags added by the "release type" setting in CMake to be shown
1387        in the configuration summary.
1388    
1389    
1390    Version 7.8 05-Sep-08
1391  ---------------------  ---------------------
1392    
1393  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 31  Version 8.0 02 Jul-08 Line 1417  Version 8.0 02 Jul-08
1417    
1418  7.  Added two (int) casts to pcregrep when printing the difference of two  7.  Added two (int) casts to pcregrep when printing the difference of two
1419      pointers, in case they are 64-bit values.      pointers, in case they are 64-bit values.
1420    
1421  8.  Added comments about Mac OS X stack usage to the pcrestack man page and to  8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1422      test 2 if it fails.      test 2 if it fails.
1423    
1424  9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,  9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1425      and a #define of that name to empty if it is not externally set. This is to      and a #define of that name to empty if it is not externally set. This is to
1426      allow users of MSVC to set it if necessary.      allow users of MSVC to set it if necessary.
1427    
1428  10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from  10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1429      the convenience functions in the pcre_get.c source file.      the convenience functions in the pcre_get.c source file.
1430    
1431    11. An option change at the start of a pattern that had top-level alternatives
1432        could cause overwriting and/or a crash. This command provoked a crash in
1433        some environments:
1434    
1435          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1436    
1437        This potential security problem was recorded as CVE-2008-2371.
1438    
1439    12. For a pattern where the match had to start at the beginning or immediately
1440        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1441        pcre_dfa_exec() could read past the end of the passed subject if there was
1442        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1443        pcretest so that it places the subject at the end of its malloc-ed buffer.
1444    
1445    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1446        exec() might read past the end of the data buffer in UTF-8 mode.
1447    
1448    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1449        the data contained the byte 0x85 as part of a UTF-8 character within its
1450        first line. This applied both to normal and DFA matching.
1451    
1452    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1453        /^[^d]*?$/8 failed to match "abc".
1454    
1455    16. Added a missing copyright notice to pcrecpp_internal.h.
1456    
1457    17. Make it more clear in the documentation that values returned from
1458        pcre_exec() in ovector are byte offsets, not character counts.
1459    
1460    18. Tidied a few places to stop certain compilers from issuing warnings.
1461    
1462    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1463        supplied by Stefan Weber. I made a further small update for 7.8 because
1464        there is a change of source arrangements: the pcre_searchfuncs.c module is
1465        replaced by pcre_ucd.c.
1466    
1467    
1468  Version 7.7 07-May-08  Version 7.7 07-May-08
1469  ---------------------  ---------------------

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