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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 09-Aug-07  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    
100    Version 8.30 04-February-2012
101    -----------------------------
102    
103    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
104        name is defined in ctype.h.
105    
106    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
107        only in quite long subpatterns.
108    
109    3.  Removed the function pcre_info(), which has been obsolete and deprecated
110        since it was replaced by pcre_fullinfo() in February 2000.
111    
112    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
113        match a (*MARK), and the match failed at the start of the subject, a
114        reference to memory before the start of the subject could occur. This bug
115        was introduced by fix 17 of release 8.21.
116    
117    5.  A reference to an unset group with zero minimum repetition was giving
118        totally wrong answers (in non-JavaScript-compatibility mode). For example,
119        /(another)?(\1?)test/ matched against "hello world test". This bug was
120        introduced in release 8.13.
121    
122    6.  Add support for 16-bit character strings (a large amount of work involving
123        many changes and refactorings).
124    
125    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
126        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
127        from a file.
128    
129    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
130        rounding is not applied in this particular case).
131    
132    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
133        if they appear, or are escaped, in patterns.
134    
135    10. Get rid of a number of -Wunused-but-set-variable warnings.
136    
137    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
138        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
139        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
140        also returns the mark "x". This bug applied to capturing parentheses,
141        non-capturing parentheses, and atomic parentheses. It also applied to some
142        assertions.
143    
144    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
145        information out of configure.ac instead of relying on pcre.h.generic, which
146        is not stored in the repository.
147    
148    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
149        -lreadline.
150    
151    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
152    
153    15. Applied Graycode's patch to put the top-level frame on the stack rather
154        than the heap when not using the stack for recursion. This gives a
155        performance improvement in many cases when recursion is not deep.
156    
157    16. Experimental code added to "pcretest -C" to output the stack frame size.
158    
159    
160    Version 8.21 12-Dec-2011
161    ------------------------
162    
163    1.  Updating the JIT compiler.
164    
165    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
166        are added as well.
167    
168    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
169        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
170        calling _pcre_jit_exec. Some extra comments are added.
171    
172    4.  (*MARK) settings inside atomic groups that do not contain any capturing
173        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
174        was introduced by change 18 for 8.20.
175    
176    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
177        ECMA-262 standard.
178    
179    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
180        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
181        This bug was probably introduced by change 9 of 8.13.
182    
183    7.  While fixing 6 above, I noticed that a number of other items were being
184        incorrectly rejected as "not fixed length". This arose partly because newer
185        opcodes had not been added to the fixed-length checking code. I have (a)
186        corrected the bug and added tests for these items, and (b) arranged for an
187        error to occur if an unknown opcode is encountered while checking for fixed
188        length instead of just assuming "not fixed length". The items that were
189        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
190        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
191        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
192    
193    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
194        being incorrectly compiled and would have given unpredicatble results.
195    
196    9.  A possessively repeated subpattern with minimum repeat count greater than
197        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
198        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
199        the first (A) could occur when it should not.
200    
201    10. Add a cast and remove a redundant test from the code.
202    
203    11. JIT should use pcre_malloc/pcre_free for allocation.
204    
205    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
206        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
207        is anything other than /usr, -L is still shown).
208    
209    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
210    
211    14. Perl does not support \N without a following name in a [] class; PCRE now
212        also gives an error.
213    
214    15. If a forward reference was repeated with an upper limit of around 2000,
215        it caused the error "internal error: overran compiling workspace". The
216        maximum number of forward references (including repeats) was limited by the
217        internal workspace, and dependent on the LINK_SIZE. The code has been
218        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
219        the default depends on LINK_SIZE. There is a new upper limit (for safety)
220        of around 200,000 forward references. While doing this, I also speeded up
221        the filling in of repeated forward references.
222    
223    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
224        incorrectly expecting the subject to contain another "a" after the start.
225    
226    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
227        in the match, the SKIP should be ignored. This was not happening; instead
228        the SKIP was being treated as NOMATCH. For patterns such as
229        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
230        tested.
231    
232    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
233        now much more compatible with Perl, in particular in cases where the result
234        is a non-match for a non-anchored pattern. For example, if
235        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
236        "m", where previously it did not return a name. A side effect of this
237        change is that for partial matches, the last encountered mark name is
238        returned, as for non matches. A number of tests that were previously not
239        Perl-compatible have been moved into the Perl-compatible test files. The
240        refactoring has had the pleasing side effect of removing one argument from
241        the match() function, thus reducing its stack requirements.
242    
243    19. If the /S+ option was used in pcretest to study a pattern using JIT,
244        subsequent uses of /S (without +) incorrectly behaved like /S+.
245    
246    21. Retrieve executable code size support for the JIT compiler and fixing
247        some warnings.
248    
249    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
250        not work when the shorter character appeared right at the end of the
251        subject string.
252    
253    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
254        systems.
255    
256    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
257        output it when the /M option is used in pcretest.
258    
259    25. The CheckMan script was not being included in the distribution. Also, added
260        an explicit "perl" to run Perl scripts from the PrepareRelease script
261        because this is reportedly needed in Windows.
262    
263    26. If study data was being save in a file and studying had not found a set of
264        "starts with" bytes for the pattern, the data written to the file (though
265        never used) was taken from uninitialized memory and so caused valgrind to
266        complain.
267    
268    27. Updated RunTest.bat as provided by Sheri Pierce.
269    
270    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
271    
272    29. Computation of memory usage for the table of capturing group names was
273        giving an unnecessarily large value.
274    
275    
276    Version 8.20 21-Oct-2011
277    ------------------------
278    
279    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
280        a POSIX class. After further experiments with Perl, which convinced me that
281        Perl has bugs and confusions, a closing square bracket is no longer allowed
282        in a POSIX name. This bug also affected patterns with classes that started
283        with full stops.
284    
285    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
286        captured substring, but while checking the failing first alternative,
287        substring 1 is temporarily captured. If the output vector supplied to
288        pcre_exec() was not big enough for this capture, the yield of the function
289        was still zero ("insufficient space for captured substrings"). This cannot
290        be totally fixed without adding another stack variable, which seems a lot
291        of expense for a edge case. However, I have improved the situation in cases
292        such as /(a)(b)x|abc/ matched against "abc", where the return code
293        indicates that fewer than the maximum number of slots in the ovector have
294        been set.
295    
296    3.  Related to (2) above: when there are more back references in a pattern than
297        slots in the output vector, pcre_exec() uses temporary memory during
298        matching, and copies in the captures as far as possible afterwards. It was
299        using the entire output vector, but this conflicts with the specification
300        that only 2/3 is used for passing back captured substrings. Now it uses
301        only the first 2/3, for compatibility. This is, of course, another edge
302        case.
303    
304    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
305        main code base, and can be used by building with --enable-jit. When this is
306        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
307        runtime --no-jit option is given.
308    
309    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
310        ovector, the return from the function was zero, implying that there were
311        other matches that did not fit. The correct "exactly full" value is now
312        returned.
313    
314    6.  If a subpattern that was called recursively or as a subroutine contained
315        (*PRUNE) or any other control that caused it to give a non-standard return,
316        invalid errors such as "Error -26 (nested recursion at the same subject
317        position)" or even infinite loops could occur.
318    
319    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
320        computing the minimum length on reaching *ACCEPT, and so ended up with the
321        wrong value of 1 rather than 0. Further investigation indicates that
322        computing a minimum subject length in the presence of *ACCEPT is difficult
323        (think back references, subroutine calls), and so I have changed the code
324        so that no minimum is registered for a pattern that contains *ACCEPT.
325    
326    8.  If (*THEN) was present in the first (true) branch of a conditional group,
327        it was not handled as intended. [But see 16 below.]
328    
329    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
330        Sheri Pierce.
331    
332    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
333        the first byte in a match must be "a".
334    
335    11. Change 17 for 8.13 increased the recursion depth for patterns like
336        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
337        pattern contains any instances of (*THEN). If it does not, the old
338        optimizations are restored. It would be nice to do this on a per-group
339        basis, but at the moment that is not feasible.
340    
341    12. In some environments, the output of pcretest -C is CRLF terminated. This
342        broke RunTest's code that checks for the link size. A single white space
343        character after the value is now allowed for.
344    
345    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
346        For "fr", it uses the Windows-specific input and output files.
347    
348    14. If (*THEN) appeared in a group that was called recursively or as a
349        subroutine, it did not work as intended. [But see next item.]
350    
351    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
352        pattern fragments (but not containing any | characters). If A and B are
353        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
354        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
355        D. In other words, Perl considers parentheses that do not contain any |
356        characters to be part of a surrounding alternative, whereas PCRE was
357        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
358        differently. PCRE now behaves in the same way as Perl, except in the case
359        of subroutine/recursion calls such as (?1) which have in any case always
360        been different (but PCRE had them first :-).
361    
362    16. Related to 15 above: Perl does not treat the | in a conditional group as
363        creating alternatives. Such a group is treated in the same way as an
364        ordinary group without any | characters when processing (*THEN). PCRE has
365        been changed to match Perl's behaviour.
366    
367    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
368        RunGrepTest script failed.
369    
370    18. Change 22 for version 13 caused atomic groups to use more stack. This is
371        inevitable for groups that contain captures, but it can lead to a lot of
372        stack use in large patterns. The old behaviour has been restored for atomic
373        groups that do not contain any capturing parentheses.
374    
375    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
376        suppress the check for a minimum subject length at run time. (If it was
377        given to pcre_exec() or pcre_dfa_exec() it did work.)
378    
379    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
380        fail to work when decoding hex characters in data strings in EBCDIC
381        environments.
382    
383    21. It appears that in at least one Mac OS environment, the isxdigit() function
384        is implemented as a macro that evaluates to its argument more than once,
385        contravening the C 90 Standard (I haven't checked a later standard). There
386        was an instance in pcretest which caused it to go wrong when processing
387        \x{...} escapes in subject strings. The has been rewritten to avoid using
388        things like p++ in the argument of isxdigit().
389    
390    
391    Version 8.13 16-Aug-2011
392    ------------------------
393    
394    1.  The Unicode data tables have been updated to Unicode 6.0.0.
395    
396    2.  Two minor typos in pcre_internal.h have been fixed.
397    
398    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
399        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
400        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
401    
402    4.  There were a number of related bugs in the code for matching backrefences
403        caselessly in UTF-8 mode when codes for the characters concerned were
404        different numbers of bytes. For example, U+023A and U+2C65 are an upper
405        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
406        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
407        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
408        2-byte code at the end of the subject (it thought there wasn't enough data
409        left).
410    
411    5.  Comprehensive information about what went wrong is now returned by
412        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
413        as the output vector has at least 2 elements. The offset of the start of
414        the failing character and a reason code are placed in the vector.
415    
416    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
417        now returned is for the first byte of the failing character, instead of the
418        last byte inspected. This is an incompatible change, but I hope it is small
419        enough not to be a problem. It makes the returned offset consistent with
420        pcre_exec() and pcre_dfa_exec().
421    
422    7.  pcretest now gives a text phrase as well as the error number when
423        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
424        failure, the offset and reason code are output.
425    
426    8.  When \R was used with a maximizing quantifier it failed to skip backwards
427        over a \r\n pair if the subsequent match failed. Instead, it just skipped
428        back over a single character (\n). This seems wrong (because it treated the
429        two characters as a single entity when going forwards), conflicts with the
430        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
431        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
432        has been changed.
433    
434    9.  Some internal refactoring has changed the processing so that the handling
435        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
436        time (the PCRE_DOTALL option was changed this way some time ago: version
437        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
438        which was always a bit of a fudge. It also means that there is one less
439        argument for the match() function, which reduces its stack requirements
440        slightly. This change also fixes an incompatibility with Perl: the pattern
441        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
442    
443    10. More internal refactoring has drastically reduced the number of recursive
444        calls to match() for possessively repeated groups such as (abc)++ when
445        using pcre_exec().
446    
447    11. While implementing 10, a number of bugs in the handling of groups were
448        discovered and fixed:
449    
450        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
451        (a|)*(?1) gave a compile-time internal error.
452        ((a|)+)+  did not notice that the outer group could match an empty string.
453        (^a|^)+   was not marked as anchored.
454        (.*a|.*)+ was not marked as matching at start or after a newline.
455    
456    12. Yet more internal refactoring has removed another argument from the match()
457        function. Special calls to this function are now indicated by setting a
458        value in a variable in the "match data" data block.
459    
460    13. Be more explicit in pcre_study() instead of relying on "default" for
461        opcodes that mean there is no starting character; this means that when new
462        ones are added and accidentally left out of pcre_study(), testing should
463        pick them up.
464    
465    14. The -s option of pcretest has been documented for ages as being an old
466        synonym of -m (show memory usage). I have changed it to mean "force study
467        for every regex", that is, assume /S for every regex. This is similar to -i
468        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
469        using it. It makes it easier to run collections of tests with and without
470        study enabled, and thereby test pcre_study() more easily. All the standard
471        tests are now run with and without -s (but some patterns can be marked as
472        "never study" - see 20 below).
473    
474    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
475        restoration of the capturing data to the outer values was not happening
476        correctly.
477    
478    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
479        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
480        pattern had matched an empty string, and so incorrectly returned a no
481        match.
482    
483    17. There was optimizing code for the last branch of non-capturing parentheses,
484        and also for the obeyed branch of a conditional subexpression, which used
485        tail recursion to cut down on stack usage. Unfortunately, now that there is
486        the possibility of (*THEN) occurring in these branches, tail recursion is
487        no longer possible because the return has to be checked for (*THEN). These
488        two optimizations have therefore been removed. [But see 8.20/11 above.]
489    
490    18. If a pattern containing \R was studied, it was assumed that \R always
491        matched two bytes, thus causing the minimum subject length to be
492        incorrectly computed because \R can also match just one byte.
493    
494    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
495        was incorrectly computed.
496    
497    20. If /S is present twice on a test pattern in pcretest input, it now
498        *disables* studying, thereby overriding the use of -s on the command line
499        (see 14 above). This is necessary for one or two tests to keep the output
500        identical in both cases.
501    
502    21. When (*ACCEPT) was used in an assertion that matched an empty string and
503        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
504    
505    22. When an atomic group that contained a capturing parenthesis was
506        successfully matched, but the branch in which it appeared failed, the
507        capturing was not being forgotten if a higher numbered group was later
508        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
509        group 1 to "a", when in fact it should be unset. This applied to multi-
510        branched capturing and non-capturing groups, repeated or not, and also to
511        positive assertions (capturing in negative assertions does not happen
512        in PCRE) and also to nested atomic groups.
513    
514    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
515        subject after a captured substring, to make it easier to tell which of a
516        number of identical substrings has been captured.
517    
518    24. The way atomic groups are processed by pcre_exec() has been changed so that
519        if they are repeated, backtracking one repetition now resets captured
520        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
521        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
522        "aaa". Previously, it would have been "a". As part of this code
523        refactoring, the way recursive calls are handled has also been changed.
524    
525    25. If an assertion condition captured any substrings, they were not passed
526        back unless some other capturing happened later. For example, if
527        (?(?=(a))a) was matched against "a", no capturing was returned.
528    
529    26. When studying a pattern that contained subroutine calls or assertions,
530        the code for finding the minimum length of a possible match was handling
531        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
532        group 1 called group 2 while simultaneously a separate group 2 called group
533        1). A stack overflow occurred in this case. I have fixed this by limiting
534        the recursion depth to 10.
535    
536    27. Updated RunTest.bat in the distribution to the version supplied by Tom
537        Fortmann. This supports explicit test numbers on the command line, and has
538        argument validation and error reporting.
539    
540    28. An instance of \X with an unlimited repeat could fail if at any point the
541        first character it looked at was a mark character.
542    
543    29. Some minor code refactoring concerning Unicode properties and scripts
544        should reduce the stack requirement of match() slightly.
545    
546    30. Added the '=' option to pcretest to check the setting of unused capturing
547        slots at the end of the pattern, which are documented as being -1, but are
548        not included in the return count.
549    
550    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
551        compiled something random. Now it gives a compile-time error (as does
552        Perl).
553    
554    32. A *MARK encountered during the processing of a positive assertion is now
555        recorded and passed back (compatible with Perl).
556    
557    33. If --only-matching or --colour was set on a pcregrep call whose pattern
558        had alternative anchored branches, the search for a second match in a line
559        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
560        matched the line "0102" twice. The same bug affected patterns that started
561        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
562        twice.
563    
564    34. Previously, PCRE did not allow quantification of assertions. However, Perl
565        does, and because of capturing effects, quantifying parenthesized
566        assertions may at times be useful. Quantifiers are now allowed for
567        parenthesized assertions.
568    
569    35. A minor code tidy in pcre_compile() when checking options for \R usage.
570    
571    36. \g was being checked for fancy things in a character class, when it should
572        just be a literal "g".
573    
574    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
575        appearance of a nested POSIX class supersedes an apparent external class.
576        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
577        unescaped square brackets may also appear as part of class names. For
578        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
579        more like Perl. (But see 8.20/1 above.)
580    
581    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
582        was because it thought it was \N{name}, which is not supported).
583    
584    39. Add minix to OS list not supporting the -S option in pcretest.
585    
586    40. PCRE tries to detect cases of infinite recursion at compile time, but it
587        cannot analyze patterns in sufficient detail to catch mutual recursions
588        such as ((?1))((?2)). There is now a runtime test that gives an error if a
589        subgroup is called recursively as a subpattern for a second time at the
590        same position in the subject string. In previous releases this might have
591        been caught by the recursion limit, or it might have run out of stack.
592    
593    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
594        happen only once. PCRE was, however incorrectly giving a compile time error
595        "recursive call could loop indefinitely" because it cannot analyze the
596        pattern in sufficient detail. The compile time test no longer happens when
597        PCRE is compiling a conditional subpattern, but actual runaway loops are
598        now caught at runtime (see 40 above).
599    
600    42. It seems that Perl allows any characters other than a closing parenthesis
601        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
602        has been changed to be the same.
603    
604    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
605        as not to get warnings when autogen.sh is called. Also changed
606        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
607    
608    44. To help people who use pcregrep to scan files containing exceedingly long
609        lines, the following changes have been made:
610    
611        (a) The default value of the buffer size parameter has been increased from
612            8K to 20K. (The actual buffer used is three times this size.)
613    
614        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
615            PCRE is built.
616    
617        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
618            to be set at run time.
619    
620        (d) Numerical values in pcregrep options can be followed by K or M, for
621            example --buffer-size=50K.
622    
623        (e) If a line being scanned overflows pcregrep's buffer, an error is now
624            given and the return code is set to 2.
625    
626    45. Add a pointer to the latest mark to the callout data block.
627    
628    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
629        partial match of an empty string instead of no match. This was specific to
630        the use of ".".
631    
632    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
633        complete match instead of a partial match. This bug was dependent on both
634        the PCRE_UTF8 and PCRE_DOTALL options being set.
635    
636    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
637        starting byte set, because \b was not being ignored.
638    
639    
640    Version 8.12 15-Jan-2011
641    ------------------------
642    
643    1.  Fixed some typos in the markup of the man pages, and wrote a script that
644        checks for such things as part of the documentation building process.
645    
646    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
647        --match-limit and --recursion-limit options (added for 8.11). In
648        particular, this made one of the standard tests fail. (The integer value
649        went into the wrong half of a long int.)
650    
651    3.  If the --colour option was given to pcregrep with -v (invert match), it
652        did strange things, either producing crazy output, or crashing. It should,
653        of course, ignore a request for colour when reporting lines that do not
654        match.
655    
656    4.  Another pcregrep bug caused similar problems if --colour was specified with
657        -M (multiline) and the pattern match finished with a line ending.
658    
659    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
660        matched in multiline mode, the following line was shown as part of the
661        match. This seems wrong, so I have changed it.
662    
663    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
664        the check for further matches in the same line (so they could be coloured)
665        to overrun the end of the current line. If another match was found, it was
666        incorrectly shown (and then shown again when found in the next line).
667    
668    7.  If pcregrep was compiled under Windows, there was a reference to the
669        function pcregrep_exit() before it was defined. I am assuming this was
670        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
671        reported by a user. I've moved the definition above the reference.
672    
673    
674    Version 8.11 10-Dec-2010
675    ------------------------
676    
677    1.  (*THEN) was not working properly if there were untried alternatives prior
678        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
679        backtracked to try for "b" instead of moving to the next alternative branch
680        at the same level (in this case, to look for "c"). The Perl documentation
681        is clear that when (*THEN) is backtracked onto, it goes to the "next
682        alternative in the innermost enclosing group".
683    
684    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
685        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
686        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
687        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
688        (*THEN).
689    
690    3.  If \s appeared in a character class, it removed the VT character from
691        the class, even if it had been included by some previous item, for example
692        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
693        of \s, but is part of the POSIX "space" class.)
694    
695    4.  A partial match never returns an empty string (because you can always
696        match an empty string at the end of the subject); however the checking for
697        an empty string was starting at the "start of match" point. This has been
698        changed to the "earliest inspected character" point, because the returned
699        data for a partial match starts at this character. This means that, for
700        example, /(?<=abc)def/ gives a partial match for the subject "abc"
701        (previously it gave "no match").
702    
703    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
704        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
705        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
706        has an implication that the given string is incomplete (because a partial
707        match is preferred over a full match). For this reason, these items now
708        give a partial match in this situation. [Aside: previously, the one case
709        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
710        match rather than a full match, which was wrong by the old rules, but is
711        now correct.]
712    
713    6.  There was a bug in the handling of #-introduced comments, recognized when
714        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
715        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
716        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
717        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
718        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
719        places in pcre_compile().
720    
721    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
722        comments when looking ahead for named forward references to subpatterns,
723        the only newline sequence it recognized was NL. It now handles newlines
724        according to the set newline convention.
725    
726    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
727        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
728        cater for a lack of strerror(). These oversights have been fixed.
729    
730    9.  Added --match-limit and --recursion-limit to pcregrep.
731    
732    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
733    
734    11. When the -o option was used, pcregrep was setting a return code of 1, even
735        when matches were found, and --line-buffered was not being honoured.
736    
737    12. Added an optional parentheses number to the -o and --only-matching options
738        of pcregrep.
739    
740    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
741        can match an empty string. The code to do it in pcretest and pcredemo
742        needed fixing:
743    
744        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
745            only one byte after an empty string match just before CRLF (this case
746            just got forgotten; "any" and "anycrlf" were OK).
747    
748        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
749            mode when an empty string match preceded an ASCII character followed by
750            a non-ASCII character. (The code for advancing by one character rather
751            than one byte was nonsense.)
752    
753        (c) The pcredemo.c sample program did not have any code at all to handle
754            the cases when CRLF is a valid newline sequence.
755    
756    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
757        as a starting offset was within the subject string. There is now a new
758        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
759        negative or greater than the length of the string. In order to test this,
760        pcretest is extended to allow the setting of negative starting offsets.
761    
762    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
763        starting offset points to the beginning of a UTF-8 character was
764        unnecessarily clumsy. I tidied it up.
765    
766    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
767        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
768    
769    17. Nobody had reported that the --include_dir option, which was added in
770        release 7.7 should have been called --include-dir (hyphen, not underscore)
771        for compatibility with GNU grep. I have changed it to --include-dir, but
772        left --include_dir as an undocumented synonym, and the same for
773        --exclude-dir, though that is not available in GNU grep, at least as of
774        release 2.5.4.
775    
776    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
777        characters from a string of bytes) have been redefined so as not to use
778        loops, in order to improve performance in some environments. At the same
779        time, I abstracted some of the common code into auxiliary macros to save
780        repetition (this should not affect the compiled code).
781    
782    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
783        compile-time error is now given if \c is not followed by an ASCII
784        character, that is, a byte less than 128. (In EBCDIC mode, the code is
785        different, and any byte value is allowed.)
786    
787    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
788        START_OPTIMIZE option, which is now allowed at compile time - but just
789        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
790        to pcregrep and other applications that have no direct access to PCRE
791        options. The new /Y option in pcretest sets this option when calling
792        pcre_compile().
793    
794    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
795        back references. Groups containing recursive back references were forced to
796        be atomic by that change, but in the case of named groups, the amount of
797        memory required was incorrectly computed, leading to "Failed: internal
798        error: code overflow". This has been fixed.
799    
800    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
801        pcretest.c, to avoid build problems in some Borland environments.
802    
803    
804    Version 8.10 25-Jun-2010
805    ------------------------
806    
807    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
808        THEN.
809    
810    2.  (*ACCEPT) was not working when inside an atomic group.
811    
812    3.  Inside a character class, \B is treated as a literal by default, but
813        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
814        causes the error). The code is unchanged, but I tidied the documentation.
815    
816    4.  Inside a character class, PCRE always treated \R and \X as literals,
817        whereas Perl faults them if its -w option is set. I have changed PCRE so
818        that it faults them when PCRE_EXTRA is set.
819    
820    5.  Added support for \N, which always matches any character other than
821        newline. (It is the same as "." when PCRE_DOTALL is not set.)
822    
823    6.  When compiling pcregrep with newer versions of gcc which may have
824        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
825        declared with attribute warn_unused_result" were given. Just casting the
826        result to (void) does not stop the warnings; a more elaborate fudge is
827        needed. I've used a macro to implement this.
828    
829    7.  Minor change to pcretest.c to avoid a compiler warning.
830    
831    8.  Added four artifical Unicode properties to help with an option to make
832        \s etc use properties (see next item). The new properties are: Xan
833        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
834    
835    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
836        use Unicode properties. (*UCP) at the start of a pattern can be used to set
837        this option. Modified pcretest to add /W to test this facility. Added
838        REG_UCP to make it available via the POSIX interface.
839    
840    10. Added --line-buffered to pcregrep.
841    
842    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
843        studied, and the match started with a letter with a code point greater than
844        127 whose first byte was different to the first byte of the other case of
845        the letter, the other case of this starting letter was not recognized
846        (#976).
847    
848    12. If a pattern that was studied started with a repeated Unicode property
849        test, for example, \p{Nd}+, there was the theoretical possibility of
850        setting up an incorrect bitmap of starting bytes, but fortunately it could
851        not have actually happened in practice until change 8 above was made (it
852        added property types that matched character-matching opcodes).
853    
854    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
855        possible starting bytes for non-anchored patterns.
856    
857    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
858        \R, and also a number of cases that involve Unicode properties, both
859        explicit and implicit when PCRE_UCP is set.
860    
861    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
862        input, it could crash or give wrong results if characters with values
863        greater than 0xc0 were present in the subject string. (Detail: it assumed
864        UTF-8 input when processing these items.)
865    
866    16. Added a lot of (int) casts to avoid compiler warnings in systems where
867        size_t is 64-bit (#991).
868    
869    17. Added a check for running out of memory when PCRE is compiled with
870        --disable-stack-for-recursion (#990).
871    
872    18. If the last data line in a file for pcretest does not have a newline on
873        the end, a newline was missing in the output.
874    
875    19. The default pcre_chartables.c file recognizes only ASCII characters (values
876        less than 128) in its various bitmaps. However, there is a facility for
877        generating tables according to the current locale when PCRE is compiled. It
878        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
879        characters, are recognized by isspace() and therefore were getting set in
880        these tables, and indeed these tables seem to approximate to ISO 8859. This
881        caused a problem in UTF-8 mode when pcre_study() was used to create a list
882        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
883        which of course cannot start UTF-8 characters. I have changed the code so
884        that only real ASCII characters (less than 128) and the correct starting
885        bytes for UTF-8 encodings are set for characters greater than 127 when in
886        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
887        altogether.)
888    
889    20. Added the /T option to pcretest so as to be able to run tests with non-
890        standard character tables, thus making it possible to include the tests
891        used for 19 above in the standard set of tests.
892    
893    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
894        reference to a subpattern the other side of a comment that contains an
895        opening parenthesis caused either an internal compiling error, or a
896        reference to the wrong subpattern.
897    
898    
899    Version 8.02 19-Mar-2010
900    ------------------------
901    
902    1.  The Unicode data tables have been updated to Unicode 5.2.0.
903    
904    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
905        configured.
906    
907    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
908        original author of that file, following a query about its status.
909    
910    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
911        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
912    
913    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
914        quantifier applied to a forward-referencing subroutine call, could compile
915        incorrect code or give the error "internal error: previously-checked
916        referenced subpattern not found".
917    
918    6.  Both MS Visual Studio and Symbian OS have problems with initializing
919        variables to point to external functions. For these systems, therefore,
920        pcre_malloc etc. are now initialized to local functions that call the
921        relevant global functions.
922    
923    7.  There were two entries missing in the vectors called coptable and poptable
924        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
925        I've fixed the data, and added a kludgy way of testing at compile time that
926        the lengths are correct (equal to the number of opcodes).
927    
928    8.  Following on from 7, I added a similar kludge to check the length of the
929        eint vector in pcreposix.c.
930    
931    9.  Error texts for pcre_compile() are held as one long string to avoid too
932        much relocation at load time. To find a text, the string is searched,
933        counting zeros. There was no check for running off the end of the string,
934        which could happen if a new error number was added without updating the
935        string.
936    
937    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
938    
939    11. \K was not working if it appeared in an atomic group or in a group that
940        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
941        \K is "not well defined" if used in an assertion. PCRE now accepts it if
942        the assertion is positive, but not if it is negative.
943    
944    12. Change 11 fortuitously reduced the size of the stack frame used in the
945        "match()" function of pcre_exec.c by one pointer. Forthcoming
946        implementation of support for (*MARK) will need an extra pointer on the
947        stack; I have reserved it now, so that the stack frame size does not
948        decrease.
949    
950    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
951        item in branch that calls a recursion is a subroutine call - as in the
952        second branch in the above example - was incorrectly given the compile-
953        time error "recursive call could loop indefinitely" because pcre_compile()
954        was not correctly checking the subroutine for matching a non-empty string.
955    
956    14. The checks for overrunning compiling workspace could trigger after an
957        overrun had occurred. This is a "should never occur" error, but it can be
958        triggered by pathological patterns such as hundreds of nested parentheses.
959        The checks now trigger 100 bytes before the end of the workspace.
960    
961    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
962    
963    
964    Version 8.01 19-Jan-2010
965    ------------------------
966    
967    1.  If a pattern contained a conditional subpattern with only one branch (in
968        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
969        computed the wrong minimum data length (which is of course zero for such
970        subpatterns). This could cause incorrect "no match" results.
971    
972    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
973        the pattern is reset in the first branch, pcre_compile() failed with
974        "internal error: code overflow at offset...". This happened only when
975        the reset was to the original external option setting. (An optimization
976        abstracts leading options settings into an external setting, which was the
977        cause of this.)
978    
979    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
980        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
981        assertion pattern did not match (meaning that the assertion was true), it
982        was incorrectly treated as false if the SKIP had been reached during the
983        matching. This also applied to assertions used as conditions.
984    
985    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
986        assertion subpattern, including such a pattern used as a condition,
987        unpredictable results occurred, instead of the error return
988        PCRE_ERROR_DFA_UITEM.
989    
990    5.  The C++ GlobalReplace function was not working like Perl for the special
991        situation when an empty string is matched. It now does the fancy magic
992        stuff that is necessary.
993    
994    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
995        removed. (These were left over from very, very early versions of PCRE.)
996    
997    7.  Some cosmetic changes to the code to make life easier when compiling it
998        as part of something else:
999    
1000        (a) Change DEBUG to PCRE_DEBUG.
1001    
1002        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1003            called "current" as "current_branch", to prevent a collision with the
1004            Linux macro when compiled as a kernel module.
1005    
1006        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1007            prevent a collision with the Linux macro when compiled as a kernel
1008            module.
1009    
1010    8.  In pcre_compile() there are some checks for integer overflows that used to
1011        cast potentially large values to (double). This has been changed to that
1012        when building, a check for int64_t is made, and if it is found, it is used
1013        instead, thus avoiding the use of floating point arithmetic. (There is no
1014        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1015        double.
1016    
1017    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1018        2005 (difference between two addresses compared to an unsigned value).
1019    
1020    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1021        custom one, because of the following reported problem in Windows:
1022    
1023          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1024              under Win32.
1025          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1026              therefore missing the function definition.
1027          - The compiler thus generates a "C" signature for the test function.
1028          - The linker fails to find the "C" function.
1029          - PCRE fails to configure if asked to do so against libbz2.
1030    
1031    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1032        messages were output:
1033    
1034          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1035          rerunning libtoolize, to keep the correct libtool macros in-tree.
1036          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1037    
1038        I have done both of these things.
1039    
1040    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1041        most of the time, it *can* run out if it is given a pattern that contains a
1042        runaway infinite recursion. I updated the discussion in the pcrestack man
1043        page.
1044    
1045    13. Now that we have gone to the x.xx style of version numbers, the minor
1046        version may start with zero. Using 08 or 09 is a bad idea because users
1047        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1048        interpreted as invalid octal numbers. I've updated the previous comment in
1049        configure.ac, and also added a check that gives an error if 08 or 09 are
1050        used.
1051    
1052    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1053        causing partial matching to fail when the end of the subject matched \W
1054        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1055    
1056    15. There were some discrepancies between the declarations in pcre_internal.h
1057        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1058        their definitions. The declarations used "const uschar *" and the
1059        definitions used USPTR. Even though USPTR is normally defined as "const
1060        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1061        reported that: "This difference in casting confuses some C++ compilers, for
1062        example, SunCC recognizes above declarations as different functions and
1063        generates broken code for hbpcre." I have changed the declarations to use
1064        USPTR.
1065    
1066    16. GNU libtool is named differently on some systems. The autogen.sh script now
1067        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1068        (FreeBSD).
1069    
1070    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1071        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1072        comment: "Figure out how to create a longlong from a string: strtoll and
1073        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1074        instance, but it only takes 2 args instead of 3!"
1075    
1076    18. A subtle bug concerned with back references has been fixed by a change of
1077        specification, with a corresponding code fix. A pattern such as
1078        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1079        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1080        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1081        same bug. Such groups have to be quantified to be useful, or contained
1082        inside another quantified group. (If there's no repetition, the reference
1083        can never match.) The problem arises because, having left the group and
1084        moved on to the rest of the pattern, a later failure that backtracks into
1085        the group uses the captured value from the final iteration of the group
1086        rather than the correct earlier one. I have fixed this in PCRE by forcing
1087        any group that contains a reference to itself to be an atomic group; that
1088        is, there cannot be any backtracking into it once it has completed. This is
1089        similar to recursive and subroutine calls.
1090    
1091    
1092    Version 8.00 19-Oct-09
1093    ----------------------
1094    
1095    1.  The table for translating pcre_compile() error codes into POSIX error codes
1096        was out-of-date, and there was no check on the pcre_compile() error code
1097        being within the table. This could lead to an OK return being given in
1098        error.
1099    
1100    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1101        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1102        in a Windows environment.
1103    
1104    3.  The pcregrep --count option prints the count for each file even when it is
1105        zero, as does GNU grep. However, pcregrep was also printing all files when
1106        --files-with-matches was added. Now, when both options are given, it prints
1107        counts only for those files that have at least one match. (GNU grep just
1108        prints the file name in this circumstance, but including the count seems
1109        more useful - otherwise, why use --count?) Also ensured that the
1110        combination -clh just lists non-zero counts, with no names.
1111    
1112    4.  The long form of the pcregrep -F option was incorrectly implemented as
1113        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1114        but it seems right to fix it, and I didn't think it was worth preserving
1115        the old behaviour.
1116    
1117    5.  The command line items --regex=pattern and --regexp=pattern were not
1118        recognized by pcregrep, which required --regex pattern or --regexp pattern
1119        (with a space rather than an '='). The man page documented the '=' forms,
1120        which are compatible with GNU grep; these now work.
1121    
1122    6.  No libpcreposix.pc file was created for pkg-config; there was just
1123        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1124    
1125    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1126        when UCP support is not needed, by modifying the Python script that
1127        generates it from Unicode data files. This should not matter if the module
1128        is correctly used as a library, but I received one complaint about 50K of
1129        unwanted data. My guess is that the person linked everything into his
1130        program rather than using a library. Anyway, it does no harm.
1131    
1132    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1133        was a minimum greater than 1 for a wide character in a possessive
1134        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1135        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1136        character. Chaos in the form of incorrect output or a compiling loop could
1137        result.
1138    
1139    9.  The restrictions on what a pattern can contain when partial matching is
1140        requested for pcre_exec() have been removed. All patterns can now be
1141        partially matched by this function. In addition, if there are at least two
1142        slots in the offset vector, the offset of the earliest inspected character
1143        for the match and the offset of the end of the subject are set in them when
1144        PCRE_ERROR_PARTIAL is returned.
1145    
1146    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1147        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1148        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1149        and may be more useful for multi-segment matching.
1150    
1151    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1152        used to be given if ever the end of the subject was reached; now it is
1153        given only if matching could not proceed because another character was
1154        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1155        string "Z", which now yields "no match" instead of "partial match". In the
1156        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1157        final character ended with (*FAIL).
1158    
1159    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1160        if the pattern had a "must contain" character that was already found in the
1161        earlier partial match, unless partial matching was again requested. For
1162        example, with the pattern /dog.(body)?/, the "must contain" character is
1163        "g". If the first part-match was for the string "dog", restarting with
1164        "sbody" failed. This bug has been fixed.
1165    
1166    13. The string returned by pcre_dfa_exec() after a partial match has been
1167        changed so that it starts at the first inspected character rather than the
1168        first character of the match. This makes a difference only if the pattern
1169        starts with a lookbehind assertion or \b or \B (\K is not supported by
1170        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1171        matching functions compatible, and I think it's the right thing to do.
1172    
1173    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1174        so that the demonstration program is easily available in environments where
1175        PCRE has not been installed from source.
1176    
1177    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1178        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1179        library.
1180    
1181    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1182        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1183        is not the first non-POSIX option to be added. Clearly some people find
1184        these options useful.
1185    
1186    17. If a caller to the POSIX matching function regexec() passes a non-zero
1187        value for nmatch with a NULL value for pmatch, the value of
1188        nmatch is forced to zero.
1189    
1190    18. RunGrepTest did not have a test for the availability of the -u option of
1191        the diff command, as RunTest does. It now checks in the same way as
1192        RunTest, and also checks for the -b option.
1193    
1194    19. If an odd number of negated classes containing just a single character
1195        interposed, within parentheses, between a forward reference to a named
1196        subpattern and the definition of the subpattern, compilation crashed with
1197        an internal error, complaining that it could not find the referenced
1198        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1199        [The bug was that it was starting one character too far in when skipping
1200        over the character class, thus treating the ] as data rather than
1201        terminating the class. This meant it could skip too much.]
1202    
1203    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1204        /g option in pcretest when the pattern contains \K, which makes it possible
1205        to have an empty string match not at the start, even when the pattern is
1206        anchored. Updated pcretest and pcredemo to use this option.
1207    
1208    21. If the maximum number of capturing subpatterns in a recursion was greater
1209        than the maximum at the outer level, the higher number was returned, but
1210        with unset values at the outer level. The correct (outer level) value is
1211        now given.
1212    
1213    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1214        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1215        make it do so. The string so far is captured, making this feature
1216        compatible with Perl.
1217    
1218    23. The tests have been re-organized, adding tests 11 and 12, to make it
1219        possible to check the Perl 5.10 features against Perl 5.10.
1220    
1221    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1222        pattern matches a fixed length string. PCRE did not allow this; now it
1223        does. Neither allows recursion.
1224    
1225    25. I finally figured out how to implement a request to provide the minimum
1226        length of subject string that was needed in order to match a given pattern.
1227        (It was back references and recursion that I had previously got hung up
1228        on.) This code has now been added to pcre_study(); it finds a lower bound
1229        to the length of subject needed. It is not necessarily the greatest lower
1230        bound, but using it to avoid searching strings that are too short does give
1231        some useful speed-ups. The value is available to calling programs via
1232        pcre_fullinfo().
1233    
1234    26. While implementing 25, I discovered to my embarrassment that pcretest had
1235        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1236        study optimizations had never been tested with that matching function.
1237        Oops. What is worse, even when it was passed study data, there was a bug in
1238        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1239        were also very few tests of studied patterns with pcre_dfa_exec().
1240    
1241    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1242        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1243        on the other side of the coin, they are no longer allowed to have different
1244        names, because these cannot be distinguished in PCRE, and this has caused
1245        confusion. (This is a difference from Perl.)
1246    
1247    28. When duplicate subpattern names are present (necessarily with different
1248        numbers, as required by 27 above), and a test is made by name in a
1249        conditional pattern, either for a subpattern having been matched, or for
1250        recursion in such a pattern, all the associated numbered subpatterns are
1251        tested, and the overall condition is true if the condition is true for any
1252        one of them. This is the way Perl works, and is also more like the way
1253        testing by number works.
1254    
1255    
1256    Version 7.9 11-Apr-09
1257    ---------------------
1258    
1259    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1260        (pcretest), all targets were linked against these libraries. This included
1261        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1262        libraries. This caused unwanted dependencies to be created. This problem
1263        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1264        pcretest is linked with readline.
1265    
1266    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1267        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1268        moved outside it again, because FALSE and TRUE are already defined in AIX,
1269        but BOOL is not.
1270    
1271    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1272        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1273    
1274    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1275        hyphens) following file names and line numbers when outputting matching
1276        lines. This is not true; no spaces are inserted. I have also clarified the
1277        wording for the --colour (or --color) option.
1278    
1279    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1280        was not coloured; this is different to GNU grep, so I have changed it to be
1281        the same.
1282    
1283    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1284        each matching line was coloured. Now it goes on to look for further matches
1285        of any of the test patterns, which is the same behaviour as GNU grep.
1286    
1287    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1288        doesn't make sense to accept an empty string match in pcregrep, so I have
1289        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1290        seems to be how GNU grep behaves.
1291    
1292    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1293        start or after a newline", because the conditional assertion was not being
1294        correctly handled. The rule now is that both the assertion and what follows
1295        in the first alternative must satisfy the test.
1296    
1297    9.  If auto-callout was enabled in a pattern with a conditional group whose
1298        condition was an assertion, PCRE could crash during matching, both with
1299        pcre_exec() and pcre_dfa_exec().
1300    
1301    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1302        used for matching.
1303    
1304    11. Unicode property support in character classes was not working for
1305        characters (bytes) greater than 127 when not in UTF-8 mode.
1306    
1307    12. Added the -M command line option to pcretest.
1308    
1309    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1310    
1311    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1312    
1313    16. Added comments and documentation about mis-use of no_arg in the C++
1314        wrapper.
1315    
1316    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1317        from Martin Jerabek that uses macro names for all relevant character and
1318        string constants.
1319    
1320    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1321        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1322        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1323        these, but not everybody uses configure.
1324    
1325    19. A conditional group that had only one branch was not being correctly
1326        recognized as an item that could match an empty string. This meant that an
1327        enclosing group might also not be so recognized, causing infinite looping
1328        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1329        with the subject "ab", where knowledge that the repeated group can match
1330        nothing is needed in order to break the loop.
1331    
1332    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1333        exec(), but without supplying a callout function, matching went wrong.
1334    
1335    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1336        leak if the size of the offset vector was greater than 30. When the vector
1337        is smaller, the saved offsets during recursion go onto a local stack
1338        vector, but for larger vectors malloc() is used. It was failing to free
1339        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1340        error, in fact).
1341    
1342    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1343        heapframe that is used only when UTF-8 support is enabled. This caused no
1344        problem, but was untidy.
1345    
1346    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1347        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1348        included within another project.
1349    
1350    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1351        slightly modified by me:
1352    
1353          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1354              not building pcregrep.
1355    
1356          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1357              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1358    
1359    25. Forward references, both numeric and by name, in patterns that made use of
1360        duplicate group numbers, could behave incorrectly or give incorrect errors,
1361        because when scanning forward to find the reference group, PCRE was not
1362        taking into account the duplicate group numbers. A pattern such as
1363        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1364    
1365    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1366        the feature of a custom pointer more persuasive (as requested by a user).
1367    
1368    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1369        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1370        pre-defined.
1371    
1372    28. Added support for (*UTF8) at the start of a pattern.
1373    
1374    29. Arrange for flags added by the "release type" setting in CMake to be shown
1375        in the configuration summary.
1376    
1377    
1378    Version 7.8 05-Sep-08
1379    ---------------------
1380    
1381    1.  Replaced UCP searching code with optimized version as implemented for Ad
1382        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1383        stage table and inline lookup instead of a function, giving speed ups of 2
1384        to 5 times on some simple patterns that I tested. Permission was given to
1385        distribute the MultiStage2.py script that generates the tables (it's not in
1386        the tarball, but is in the Subversion repository).
1387    
1388    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1389        scripts.
1390    
1391    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1392        a group with a zero qualifier. The result of the study could be incorrect,
1393        or the function might crash, depending on the pattern.
1394    
1395    4.  Caseless matching was not working for non-ASCII characters in back
1396        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1397        It now works when Unicode Property Support is available.
1398    
1399    5.  In pcretest, an escape such as \x{de} in the data was always generating
1400        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1401        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1402        truncation.
1403    
1404    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1405    
1406    7.  Added two (int) casts to pcregrep when printing the difference of two
1407        pointers, in case they are 64-bit values.
1408    
1409    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1410        test 2 if it fails.
1411    
1412    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1413        and a #define of that name to empty if it is not externally set. This is to
1414        allow users of MSVC to set it if necessary.
1415    
1416    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1417        the convenience functions in the pcre_get.c source file.
1418    
1419    11. An option change at the start of a pattern that had top-level alternatives
1420        could cause overwriting and/or a crash. This command provoked a crash in
1421        some environments:
1422    
1423          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1424    
1425        This potential security problem was recorded as CVE-2008-2371.
1426    
1427    12. For a pattern where the match had to start at the beginning or immediately
1428        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1429        pcre_dfa_exec() could read past the end of the passed subject if there was
1430        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1431        pcretest so that it places the subject at the end of its malloc-ed buffer.
1432    
1433    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1434        exec() might read past the end of the data buffer in UTF-8 mode.
1435    
1436    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1437        the data contained the byte 0x85 as part of a UTF-8 character within its
1438        first line. This applied both to normal and DFA matching.
1439    
1440    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1441        /^[^d]*?$/8 failed to match "abc".
1442    
1443    16. Added a missing copyright notice to pcrecpp_internal.h.
1444    
1445    17. Make it more clear in the documentation that values returned from
1446        pcre_exec() in ovector are byte offsets, not character counts.
1447    
1448    18. Tidied a few places to stop certain compilers from issuing warnings.
1449    
1450    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1451        supplied by Stefan Weber. I made a further small update for 7.8 because
1452        there is a change of source arrangements: the pcre_searchfuncs.c module is
1453        replaced by pcre_ucd.c.
1454    
1455    
1456    Version 7.7 07-May-08
1457    ---------------------
1458    
1459    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1460        a string to a long long, pretend we don't even have a long long." This is
1461        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1462    
1463    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1464        pre-7.6 versions, which defined a global no_arg variable instead of putting
1465        it in the RE class. (See also #8 below.)
1466    
1467    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1468        Lopes.
1469    
1470    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1471    
1472        (1) The include/exclude patterns were being applied to the whole pathnames
1473            of files, instead of just to the final components.
1474    
1475        (2) If there was more than one level of directory, the subdirectories were
1476            skipped unless they satisfied the include/exclude conditions. This is
1477            inconsistent with GNU grep (and could even be seen as contrary to the
1478            pcregrep specification - which I improved to make it absolutely clear).
1479            The action now is always to scan all levels of directory, and just
1480            apply the include/exclude patterns to regular files.
1481    
1482    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1483        --exclude_dir in the tests to avoid scanning .svn directories.
1484    
1485    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1486        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1487        doesn't support NULs in patterns.
1488    
1489    7.  Added some missing "const"s to declarations of static tables in
1490        pcre_compile.c and pcre_dfa_exec.c.
1491    
1492    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1493        caused by fix #2  above. (Subsequently also a second patch to fix the
1494        first patch. And a third patch - this was a messy problem.)
1495    
1496    9.  Applied Craig's patch to remove the use of push_back().
1497    
1498    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1499        matching function regexec().
1500    
1501    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1502        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1503        references. PCRE supports relative numbers with this syntax (I don't think
1504        Oniguruma does).
1505    
1506    12. Previously, a group with a zero repeat such as (...){0} was completely
1507        omitted from the compiled regex. However, this means that if the group
1508        was called as a subroutine from elsewhere in the pattern, things went wrong
1509        (an internal error was given). Such groups are now left in the compiled
1510        pattern, with a new opcode that causes them to be skipped at execution
1511        time.
1512    
1513    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1514        to the way PCRE behaves:
1515    
1516        (a) A lone ] character is dis-allowed (Perl treats it as data).
1517    
1518        (b) A back reference to an unmatched subpattern matches an empty string
1519            (Perl fails the current match path).
1520    
1521        (c) A data ] in a character class must be notated as \] because if the
1522            first data character in a class is ], it defines an empty class. (In
1523            Perl it is not possible to have an empty class.) The empty class []
1524            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1525            The negative empty class [^] matches any one character, independently
1526            of the DOTALL setting.
1527    
1528    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1529        non-existent subpattern following a character class starting with ']' and
1530        containing () gave an internal compiling error instead of "reference to
1531        non-existent subpattern". Fortunately, when the pattern did exist, the
1532        compiled code was correct. (When scanning forwards to check for the
1533        existencd of the subpattern, it was treating the data ']' as terminating
1534        the class, so got the count wrong. When actually compiling, the reference
1535        was subsequently set up correctly.)
1536    
1537    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1538        it was being rejected as not supported by pcre_dfa_exec(), even though
1539        other assertions are supported. I have made pcre_dfa_exec() support
1540        (*FAIL).
1541    
1542    16. The implementation of 13c above involved the invention of a new opcode,
1543        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1544        cannot be changed at match time, I realized I could make a small
1545        improvement to matching performance by compiling OP_ALLANY instead of
1546        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1547        on the OP_ANY path.
1548    
1549    17. Compiling pcretest on Windows with readline support failed without the
1550        following two fixes: (1) Make the unistd.h include conditional on
1551        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1552    
1553    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1554        ncurses library to be included for pcretest when ReadLine support is
1555        requested, but also to allow for it to be overridden. This patch came from
1556        Daniel Bergström.
1557    
1558    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1559        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1560        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1561        spotting this.
1562    
1563    
1564    Version 7.6 28-Jan-08
1565    ---------------------
1566    
1567    1.  A character class containing a very large number of characters with
1568        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1569        overflow.
1570    
1571    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1572        HAVE_LONG_LONG is not defined.
1573    
1574    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1575        bring them up to date and include new features. This patch includes:
1576    
1577        - Fixed PH's badly added libz and libbz2 support.
1578        - Fixed a problem with static linking.
1579        - Added pcredemo. [But later removed - see 7 below.]
1580        - Fixed dftables problem and added an option.
1581        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1582            HAVE_LONG_LONG.
1583        - Added readline support for pcretest.
1584        - Added an listing of the option settings after cmake has run.
1585    
1586    4.  A user submitted a patch to Makefile that makes it easy to create
1587        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1588        Makefile.am that cause it to include this special target, without
1589        affecting anything else. Note that the same mingw target plus all
1590        the other distribution libraries and programs are now supported
1591        when configuring with CMake (see 6 below) instead of with
1592        Configure/Make.
1593    
1594    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1595        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1596        exported in the Windows port". It has not yet been confirmed that the patch
1597        solves the problem, but it does no harm.
1598    
1599    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1600        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1601        with CMake, and also correct the comment about stack recursion.
1602    
1603    7.  Remove the automatic building of pcredemo from the ./configure system and
1604        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1605        of a program that users should build themselves after PCRE is installed, so
1606        building it automatically is not really right. What is more, it gave
1607        trouble in some build environments.
1608    
1609    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1610    
1611    
1612    Version 7.5 10-Jan-08
1613    ---------------------
1614    
1615    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1616        values in parens when parsing an RE using the C++ wrapper."
1617    
1618    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1619        Characters greater than 255 were excluded from the class instead of being
1620        included.
1621    
1622    3.  The same bug as (2) above applied to negated POSIX classes such as
1623        [:^space:].
1624    
1625    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1626        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1627        I have changed it.
1628    
1629    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1630        first named subpattern) and a construct such as (?&a) would reference the
1631        first named subpattern whose name started with "a" (in other words, the
1632        length check was missing). Both these problems are fixed. "Subpattern name
1633        expected" is now given for (?&) (a zero-length name), and this patch also
1634        makes it give the same error for \k'' (previously it complained that that
1635        was a reference to a non-existent subpattern).
1636    
1637    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1638        this is right because (?- can be followed by option settings as well as by
1639        digits. I have, however, made the messages clearer.
1640    
1641    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1642        than the number used in the conditional) now cause a compile-time error.
1643        This is actually not compatible with Perl, which accepts such patterns, but
1644        treats the conditional as always being FALSE (as PCRE used to), but it
1645        seems to me that giving a diagnostic is better.
1646    
1647    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1648        and messages.
1649    
1650    9.  Fix two occurrences of "backslash" in comments that should have been
1651        "backspace".
1652    
1653    10. Remove two redundant lines of code that can never be obeyed (their function
1654        was moved elsewhere).
1655    
1656    11. The program that makes PCRE's Unicode character property table had a bug
1657        which caused it to generate incorrect table entries for sequences of
1658        characters that have the same character type, but are in different scripts.
1659        It amalgamated them into a single range, with the script of the first of
1660        them. In other words, some characters were in the wrong script. There were
1661        thirteen such cases, affecting characters in the following ranges:
1662    
1663          U+002b0 - U+002c1
1664          U+0060c - U+0060d
1665          U+0061e - U+00612
1666          U+0064b - U+0065e
1667          U+0074d - U+0076d
1668          U+01800 - U+01805
1669          U+01d00 - U+01d77
1670          U+01d9b - U+01dbf
1671          U+0200b - U+0200f
1672          U+030fc - U+030fe
1673          U+03260 - U+0327f
1674          U+0fb46 - U+0fbb1
1675          U+10450 - U+1049d
1676    
1677    12. The -o option (show only the matching part of a line) for pcregrep was not
1678        compatible with GNU grep in that, if there was more than one match in a
1679        line, it showed only the first of them. It now behaves in the same way as
1680        GNU grep.
1681    
1682    13. If the -o and -v options were combined for pcregrep, it printed a blank
1683        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1684        does the same. The return code can be used to tell if there were any
1685        non-matching lines.
1686    
1687    14. Added --file-offsets and --line-offsets to pcregrep.
1688    
1689    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1690        infinitely looping recursion. The bug was that positive lookaheads were not
1691        being skipped when checking for a possible empty match (negative lookaheads
1692        and both kinds of lookbehind were skipped).
1693    
1694    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1695        inclusion of <windows.h> to before rather than after the definition of
1696        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1697    
1698    17. Specifying a possessive quantifier with a specific limit for a Unicode
1699        character property caused pcre_compile() to compile bad code, which led at
1700        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1701        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1702        caused the error; without that there was no problem.
1703    
1704    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1705    
1706    19. Added --enable-pcretest-libreadline.
1707    
1708    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1709        RE::GlobalReplace(). As a result, the number of replacements returned was
1710        double what it should be. I removed one of the increments, but Craig sent a
1711        later patch that removed the other one (the right fix) and added unit tests
1712        that check the return values (which was not done before).
1713    
1714    21. Several CMake things:
1715    
1716        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1717            the names libpcre and libpcreposix, not just pcre and pcreposix.
1718    
1719        (2) The above change means that pcretest and pcregrep are now correctly
1720            linked with the newly-built libraries, not previously installed ones.
1721    
1722        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1723    
1724    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1725        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1726        UTF-8 newline character). The key issue is that the pattern starts .*;
1727        this means that the match must be either at the beginning, or after a
1728        newline. The bug was in the code for advancing after a failed match and
1729        checking that the new position followed a newline. It was not taking
1730        account of UTF-8 characters correctly.
1731    
1732    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1733        character classes. PCRE was not treating the sequence [:...:] as a
1734        character class unless the ... were all letters. Perl, however, seems to
1735        allow any characters between [: and :], though of course it rejects as
1736        unknown any "names" that contain non-letters, because all the known class
1737        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1738        for example, whereas PCRE did not - it did not recognize a POSIX character
1739        class. This seemed a bit dangerous, so the code has been changed to be
1740        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1741        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1742        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1743        Perl does, and where it didn't before.
1744    
1745    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1746        Windows environments %n is disabled by default.
1747    
1748    
1749    Version 7.4 21-Sep-07
1750    ---------------------
1751    
1752    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1753        means that a class such as [\s] counted as "explicit reference to CR or
1754        LF". That isn't really right - the whole point of the change was to try to
1755        help when there was an actual mention of one of the two characters. So now
1756        the change happens only if \r or \n (or a literal CR or LF) character is
1757        encountered.
1758    
1759    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1760        of both had grown to the point where there were only 3 bits left.
1761        Fortunately, there was spare space in the data structure, and so I have
1762        moved the internal flags into a new 16-bit field to free up more option
1763        bits.
1764    
1765    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1766        but did not set the internal JCHANGED flag - either of these is enough to
1767        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1768        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1769        start sets both bits.
1770    
1771    4.  Added options (at build time, compile time, exec time) to change \R from
1772        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1773    
1774    5.  doc/pcresyntax.html was missing from the distribution.
1775    
1776    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1777        compatibility, even though it is no longer used.
1778    
1779    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1780        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1781        windows.h file is present (where different names are used). [This was
1782        reversed later after testing - see 16 below.]
1783    
1784    8.  Changed all #include <config.h> to #include "config.h". There were also
1785        some further <pcre.h> cases that I changed to "pcre.h".
1786    
1787    9.  When pcregrep was used with the --colour option, it missed the line ending
1788        sequence off the lines that it output.
1789    
1790    10. It was pointed out to me that arrays of string pointers cause lots of
1791        relocations when a shared library is dynamically loaded. A technique of
1792        using a single long string with a table of offsets can drastically reduce
1793        these. I have refactored PCRE in four places to do this. The result is
1794        dramatic:
1795    
1796          Originally:                          290
1797          After changing UCP table:            187
1798          After changing error message table:   43
1799          After changing table of "verbs"       36
1800          After changing table of Posix names   22
1801    
1802        Thanks to the folks working on Gregex for glib for this insight.
1803    
1804    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1805        unicode-properties was also set.
1806    
1807    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1808    
1809    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1810        checked only for CRLF.
1811    
1812    14. Added casts to pcretest.c to avoid compiler warnings.
1813    
1814    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1815    
1816    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1817        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1818        entirely. This removes changes made in 7 above.
1819    
1820    17. The CMake files have been updated, and there is now more information about
1821        building with CMake in the NON-UNIX-USE document.
1822    
1823    
1824    Version 7.3 28-Aug-07
1825  ---------------------  ---------------------
1826    
1827   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 99  Version 7.3 09-Aug-07 Line 1919  Version 7.3 09-Aug-07
1919      full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still      full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1920      does: it's just the validity check that is more restrictive.      does: it's just the validity check that is more restrictive.
1921    
1922    16. Inserted checks for integer overflows during escape sequence (backslash)
1923        processing, and also fixed erroneous offset values for syntax errors during
1924        backslash processing.
1925    
1926    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1927        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1928    
1929    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1930        caused an overrun.
1931    
1932    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1933        something other than just ASCII characters) inside a group that had an
1934        unlimited repeat caused a loop at compile time (while checking to see
1935        whether the group could match an empty string).
1936    
1937    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1938        [\P{Any}] did so. (Error in the code for printing property names.)
1939    
1940    21. An orphan \E inside a character class could cause a crash.
1941    
1942    22. A repeated capturing bracket such as (A)? could cause a wild memory
1943        reference during compilation.
1944    
1945    23. There are several functions in pcre_compile() that scan along a compiled
1946        expression for various reasons (e.g. to see if it's fixed length for look
1947        behind). There were bugs in these functions when a repeated \p or \P was
1948        present in the pattern. These operators have additional parameters compared
1949        with \d, etc, and these were not being taken into account when moving along
1950        the compiled data. Specifically:
1951    
1952        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1953            length.
1954    
1955        (b) An item such as \pL+ within a repeated group could cause crashes or
1956            loops.
1957    
1958        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1959            "reference to non-existent subpattern" error.
1960    
1961        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1962    
1963    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1964        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1965    
1966    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1967    
1968    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1969        character were causing crashes (broken optimization).
1970    
1971    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1972        \p or \P) caused a compile-time loop.
1973    
1974    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1975        break. For example, the unstudied pattern [\r\n]A does not match the string
1976        "\r\nA" because change 7.0/46 below moves the current point on by two
1977        characters after failing to match at the start. However, the pattern \nA
1978        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1979        the same is true. There doesn't seem any very clean way out of this, but
1980        what I have chosen to do makes the common cases work: PCRE now takes note
1981        of whether there can be an explicit match for \r or \n anywhere in the
1982        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1983        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1984        pattern has explicit CR or LF references.
1985    
1986    29. Added (*CR) etc for changing newline setting at start of pattern.
1987    
1988    
1989  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07
1990  ---------------------  ---------------------

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