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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.1 12-Mar-07  Version 8.30
5    ------------
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
10    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
11        only in quite long subpatterns.
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
29    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
30        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
31        from a file.
33    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
34        rounding is not applied in this particular case).
36    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
37        if they appear, or are escaped, in patterns.
39    10. Get rid of a number of -Wunused-but-set-variable warnings.
41    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
42        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
43        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
44        also returns the mark "x". This bug applied to capturing parentheses,
45        non-capturing parentheses, and atomic parentheses. It also applied to some
46        assertions.
48    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
49        information out of configure.ac instead of relying on pcre.h.generic, which
50        is not stored in the repository.
53    Version 8.21 12-Dec-2011
54    ------------------------
56    1.  Updating the JIT compiler.
58    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
59        are added as well.
61    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
62        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
63        calling _pcre_jit_exec. Some extra comments are added.
65    4.  (*MARK) settings inside atomic groups that do not contain any capturing
66        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
67        was introduced by change 18 for 8.20.
69    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
70        ECMA-262 standard.
72    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
73        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
74        This bug was probably introduced by change 9 of 8.13.
76    7.  While fixing 6 above, I noticed that a number of other items were being
77        incorrectly rejected as "not fixed length". This arose partly because newer
78        opcodes had not been added to the fixed-length checking code. I have (a)
79        corrected the bug and added tests for these items, and (b) arranged for an
80        error to occur if an unknown opcode is encountered while checking for fixed
81        length instead of just assuming "not fixed length". The items that were
82        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
83        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
84        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
86    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
87        being incorrectly compiled and would have given unpredicatble results.
89    9.  A possessively repeated subpattern with minimum repeat count greater than
90        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
91        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
92        the first (A) could occur when it should not.
94    10. Add a cast and remove a redundant test from the code.
96    11. JIT should use pcre_malloc/pcre_free for allocation.
98    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
99        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
100        is anything other than /usr, -L is still shown).
102    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
104    14. Perl does not support \N without a following name in a [] class; PCRE now
105        also gives an error.
107    15. If a forward reference was repeated with an upper limit of around 2000,
108        it caused the error "internal error: overran compiling workspace". The
109        maximum number of forward references (including repeats) was limited by the
110        internal workspace, and dependent on the LINK_SIZE. The code has been
111        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
112        the default depends on LINK_SIZE. There is a new upper limit (for safety)
113        of around 200,000 forward references. While doing this, I also speeded up
114        the filling in of repeated forward references.
116    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
117        incorrectly expecting the subject to contain another "a" after the start.
119    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
120        in the match, the SKIP should be ignored. This was not happening; instead
121        the SKIP was being treated as NOMATCH. For patterns such as
122        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
123        tested.
125    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
126        now much more compatible with Perl, in particular in cases where the result
127        is a non-match for a non-anchored pattern. For example, if
128        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
129        "m", where previously it did not return a name. A side effect of this
130        change is that for partial matches, the last encountered mark name is
131        returned, as for non matches. A number of tests that were previously not
132        Perl-compatible have been moved into the Perl-compatible test files. The
133        refactoring has had the pleasing side effect of removing one argument from
134        the match() function, thus reducing its stack requirements.
136    19. If the /S+ option was used in pcretest to study a pattern using JIT,
137        subsequent uses of /S (without +) incorrectly behaved like /S+.
139    21. Retrieve executable code size support for the JIT compiler and fixing
140        some warnings.
142    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
143        not work when the shorter character appeared right at the end of the
144        subject string.
146    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
147        systems.
149    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
150        output it when the /M option is used in pcretest.
152    25. The CheckMan script was not being included in the distribution. Also, added
153        an explicit "perl" to run Perl scripts from the PrepareRelease script
154        because this is reportedly needed in Windows.
156    26. If study data was being save in a file and studying had not found a set of
157        "starts with" bytes for the pattern, the data written to the file (though
158        never used) was taken from uninitialized memory and so caused valgrind to
159        complain.
161    27. Updated RunTest.bat as provided by Sheri Pierce.
163    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
165    29. Computation of memory usage for the table of capturing group names was
166        giving an unnecessarily large value.
169    Version 8.20 21-Oct-2011
170    ------------------------
172    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
173        a POSIX class. After further experiments with Perl, which convinced me that
174        Perl has bugs and confusions, a closing square bracket is no longer allowed
175        in a POSIX name. This bug also affected patterns with classes that started
176        with full stops.
178    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
179        captured substring, but while checking the failing first alternative,
180        substring 1 is temporarily captured. If the output vector supplied to
181        pcre_exec() was not big enough for this capture, the yield of the function
182        was still zero ("insufficient space for captured substrings"). This cannot
183        be totally fixed without adding another stack variable, which seems a lot
184        of expense for a edge case. However, I have improved the situation in cases
185        such as /(a)(b)x|abc/ matched against "abc", where the return code
186        indicates that fewer than the maximum number of slots in the ovector have
187        been set.
189    3.  Related to (2) above: when there are more back references in a pattern than
190        slots in the output vector, pcre_exec() uses temporary memory during
191        matching, and copies in the captures as far as possible afterwards. It was
192        using the entire output vector, but this conflicts with the specification
193        that only 2/3 is used for passing back captured substrings. Now it uses
194        only the first 2/3, for compatibility. This is, of course, another edge
195        case.
197    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
198        main code base, and can be used by building with --enable-jit. When this is
199        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
200        runtime --no-jit option is given.
202    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
203        ovector, the return from the function was zero, implying that there were
204        other matches that did not fit. The correct "exactly full" value is now
205        returned.
207    6.  If a subpattern that was called recursively or as a subroutine contained
208        (*PRUNE) or any other control that caused it to give a non-standard return,
209        invalid errors such as "Error -26 (nested recursion at the same subject
210        position)" or even infinite loops could occur.
212    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
213        computing the minimum length on reaching *ACCEPT, and so ended up with the
214        wrong value of 1 rather than 0. Further investigation indicates that
215        computing a minimum subject length in the presence of *ACCEPT is difficult
216        (think back references, subroutine calls), and so I have changed the code
217        so that no minimum is registered for a pattern that contains *ACCEPT.
219    8.  If (*THEN) was present in the first (true) branch of a conditional group,
220        it was not handled as intended. [But see 16 below.]
222    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
223        Sheri Pierce.
225    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
226        the first byte in a match must be "a".
228    11. Change 17 for 8.13 increased the recursion depth for patterns like
229        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
230        pattern contains any instances of (*THEN). If it does not, the old
231        optimizations are restored. It would be nice to do this on a per-group
232        basis, but at the moment that is not feasible.
234    12. In some environments, the output of pcretest -C is CRLF terminated. This
235        broke RunTest's code that checks for the link size. A single white space
236        character after the value is now allowed for.
238    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
239        For "fr", it uses the Windows-specific input and output files.
241    14. If (*THEN) appeared in a group that was called recursively or as a
242        subroutine, it did not work as intended. [But see next item.]
244    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
245        pattern fragments (but not containing any | characters). If A and B are
246        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
247        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
248        D. In other words, Perl considers parentheses that do not contain any |
249        characters to be part of a surrounding alternative, whereas PCRE was
250        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
251        differently. PCRE now behaves in the same way as Perl, except in the case
252        of subroutine/recursion calls such as (?1) which have in any case always
253        been different (but PCRE had them first :-).
255    16. Related to 15 above: Perl does not treat the | in a conditional group as
256        creating alternatives. Such a group is treated in the same way as an
257        ordinary group without any | characters when processing (*THEN). PCRE has
258        been changed to match Perl's behaviour.
260    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
261        RunGrepTest script failed.
263    18. Change 22 for version 13 caused atomic groups to use more stack. This is
264        inevitable for groups that contain captures, but it can lead to a lot of
265        stack use in large patterns. The old behaviour has been restored for atomic
266        groups that do not contain any capturing parentheses.
268    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
269        suppress the check for a minimum subject length at run time. (If it was
270        given to pcre_exec() or pcre_dfa_exec() it did work.)
272    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
273        fail to work when decoding hex characters in data strings in EBCDIC
274        environments.
276    21. It appears that in at least one Mac OS environment, the isxdigit() function
277        is implemented as a macro that evaluates to its argument more than once,
278        contravening the C 90 Standard (I haven't checked a later standard). There
279        was an instance in pcretest which caused it to go wrong when processing
280        \x{...} escapes in subject strings. The has been rewritten to avoid using
281        things like p++ in the argument of isxdigit().
284    Version 8.13 16-Aug-2011
285    ------------------------
287    1.  The Unicode data tables have been updated to Unicode 6.0.0.
289    2.  Two minor typos in pcre_internal.h have been fixed.
291    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
292        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
293        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
295    4.  There were a number of related bugs in the code for matching backrefences
296        caselessly in UTF-8 mode when codes for the characters concerned were
297        different numbers of bytes. For example, U+023A and U+2C65 are an upper
298        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
299        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
300        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
301        2-byte code at the end of the subject (it thought there wasn't enough data
302        left).
304    5.  Comprehensive information about what went wrong is now returned by
305        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
306        as the output vector has at least 2 elements. The offset of the start of
307        the failing character and a reason code are placed in the vector.
309    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
310        now returned is for the first byte of the failing character, instead of the
311        last byte inspected. This is an incompatible change, but I hope it is small
312        enough not to be a problem. It makes the returned offset consistent with
313        pcre_exec() and pcre_dfa_exec().
315    7.  pcretest now gives a text phrase as well as the error number when
316        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
317        failure, the offset and reason code are output.
319    8.  When \R was used with a maximizing quantifier it failed to skip backwards
320        over a \r\n pair if the subsequent match failed. Instead, it just skipped
321        back over a single character (\n). This seems wrong (because it treated the
322        two characters as a single entity when going forwards), conflicts with the
323        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
324        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
325        has been changed.
327    9.  Some internal refactoring has changed the processing so that the handling
328        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
329        time (the PCRE_DOTALL option was changed this way some time ago: version
330        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
331        which was always a bit of a fudge. It also means that there is one less
332        argument for the match() function, which reduces its stack requirements
333        slightly. This change also fixes an incompatibility with Perl: the pattern
334        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
336    10. More internal refactoring has drastically reduced the number of recursive
337        calls to match() for possessively repeated groups such as (abc)++ when
338        using pcre_exec().
340    11. While implementing 10, a number of bugs in the handling of groups were
341        discovered and fixed:
343        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
344        (a|)*(?1) gave a compile-time internal error.
345        ((a|)+)+  did not notice that the outer group could match an empty string.
346        (^a|^)+   was not marked as anchored.
347        (.*a|.*)+ was not marked as matching at start or after a newline.
349    12. Yet more internal refactoring has removed another argument from the match()
350        function. Special calls to this function are now indicated by setting a
351        value in a variable in the "match data" data block.
353    13. Be more explicit in pcre_study() instead of relying on "default" for
354        opcodes that mean there is no starting character; this means that when new
355        ones are added and accidentally left out of pcre_study(), testing should
356        pick them up.
358    14. The -s option of pcretest has been documented for ages as being an old
359        synonym of -m (show memory usage). I have changed it to mean "force study
360        for every regex", that is, assume /S for every regex. This is similar to -i
361        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
362        using it. It makes it easier to run collections of tests with and without
363        study enabled, and thereby test pcre_study() more easily. All the standard
364        tests are now run with and without -s (but some patterns can be marked as
365        "never study" - see 20 below).
367    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
368        restoration of the capturing data to the outer values was not happening
369        correctly.
371    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
372        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
373        pattern had matched an empty string, and so incorrectly returned a no
374        match.
376    17. There was optimizing code for the last branch of non-capturing parentheses,
377        and also for the obeyed branch of a conditional subexpression, which used
378        tail recursion to cut down on stack usage. Unfortunately, now that there is
379        the possibility of (*THEN) occurring in these branches, tail recursion is
380        no longer possible because the return has to be checked for (*THEN). These
381        two optimizations have therefore been removed. [But see 8.20/11 above.]
383    18. If a pattern containing \R was studied, it was assumed that \R always
384        matched two bytes, thus causing the minimum subject length to be
385        incorrectly computed because \R can also match just one byte.
387    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
388        was incorrectly computed.
390    20. If /S is present twice on a test pattern in pcretest input, it now
391        *disables* studying, thereby overriding the use of -s on the command line
392        (see 14 above). This is necessary for one or two tests to keep the output
393        identical in both cases.
395    21. When (*ACCEPT) was used in an assertion that matched an empty string and
396        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
398    22. When an atomic group that contained a capturing parenthesis was
399        successfully matched, but the branch in which it appeared failed, the
400        capturing was not being forgotten if a higher numbered group was later
401        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
402        group 1 to "a", when in fact it should be unset. This applied to multi-
403        branched capturing and non-capturing groups, repeated or not, and also to
404        positive assertions (capturing in negative assertions does not happen
405        in PCRE) and also to nested atomic groups.
407    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
408        subject after a captured substring, to make it easier to tell which of a
409        number of identical substrings has been captured.
411    24. The way atomic groups are processed by pcre_exec() has been changed so that
412        if they are repeated, backtracking one repetition now resets captured
413        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
414        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
415        "aaa". Previously, it would have been "a". As part of this code
416        refactoring, the way recursive calls are handled has also been changed.
418    25. If an assertion condition captured any substrings, they were not passed
419        back unless some other capturing happened later. For example, if
420        (?(?=(a))a) was matched against "a", no capturing was returned.
422    26. When studying a pattern that contained subroutine calls or assertions,
423        the code for finding the minimum length of a possible match was handling
424        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
425        group 1 called group 2 while simultaneously a separate group 2 called group
426        1). A stack overflow occurred in this case. I have fixed this by limiting
427        the recursion depth to 10.
429    27. Updated RunTest.bat in the distribution to the version supplied by Tom
430        Fortmann. This supports explicit test numbers on the command line, and has
431        argument validation and error reporting.
433    28. An instance of \X with an unlimited repeat could fail if at any point the
434        first character it looked at was a mark character.
436    29. Some minor code refactoring concerning Unicode properties and scripts
437        should reduce the stack requirement of match() slightly.
439    30. Added the '=' option to pcretest to check the setting of unused capturing
440        slots at the end of the pattern, which are documented as being -1, but are
441        not included in the return count.
443    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
444        compiled something random. Now it gives a compile-time error (as does
445        Perl).
447    32. A *MARK encountered during the processing of a positive assertion is now
448        recorded and passed back (compatible with Perl).
450    33. If --only-matching or --colour was set on a pcregrep call whose pattern
451        had alternative anchored branches, the search for a second match in a line
452        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
453        matched the line "0102" twice. The same bug affected patterns that started
454        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
455        twice.
457    34. Previously, PCRE did not allow quantification of assertions. However, Perl
458        does, and because of capturing effects, quantifying parenthesized
459        assertions may at times be useful. Quantifiers are now allowed for
460        parenthesized assertions.
462    35. A minor code tidy in pcre_compile() when checking options for \R usage.
464    36. \g was being checked for fancy things in a character class, when it should
465        just be a literal "g".
467    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
468        appearance of a nested POSIX class supersedes an apparent external class.
469        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
470        unescaped square brackets may also appear as part of class names. For
471        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
472        more like Perl. (But see 8.20/1 above.)
474    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
475        was because it thought it was \N{name}, which is not supported).
477    39. Add minix to OS list not supporting the -S option in pcretest.
479    40. PCRE tries to detect cases of infinite recursion at compile time, but it
480        cannot analyze patterns in sufficient detail to catch mutual recursions
481        such as ((?1))((?2)). There is now a runtime test that gives an error if a
482        subgroup is called recursively as a subpattern for a second time at the
483        same position in the subject string. In previous releases this might have
484        been caught by the recursion limit, or it might have run out of stack.
486    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
487        happen only once. PCRE was, however incorrectly giving a compile time error
488        "recursive call could loop indefinitely" because it cannot analyze the
489        pattern in sufficient detail. The compile time test no longer happens when
490        PCRE is compiling a conditional subpattern, but actual runaway loops are
491        now caught at runtime (see 40 above).
493    42. It seems that Perl allows any characters other than a closing parenthesis
494        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
495        has been changed to be the same.
497    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
498        as not to get warnings when autogen.sh is called. Also changed
499        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
501    44. To help people who use pcregrep to scan files containing exceedingly long
502        lines, the following changes have been made:
504        (a) The default value of the buffer size parameter has been increased from
505            8K to 20K. (The actual buffer used is three times this size.)
507        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
508            PCRE is built.
510        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
511            to be set at run time.
513        (d) Numerical values in pcregrep options can be followed by K or M, for
514            example --buffer-size=50K.
516        (e) If a line being scanned overflows pcregrep's buffer, an error is now
517            given and the return code is set to 2.
519    45. Add a pointer to the latest mark to the callout data block.
521    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
522        partial match of an empty string instead of no match. This was specific to
523        the use of ".".
525    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
526        complete match instead of a partial match. This bug was dependent on both
527        the PCRE_UTF8 and PCRE_DOTALL options being set.
529    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
530        starting byte set, because \b was not being ignored.
533    Version 8.12 15-Jan-2011
534    ------------------------
536    1.  Fixed some typos in the markup of the man pages, and wrote a script that
537        checks for such things as part of the documentation building process.
539    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
540        --match-limit and --recursion-limit options (added for 8.11). In
541        particular, this made one of the standard tests fail. (The integer value
542        went into the wrong half of a long int.)
544    3.  If the --colour option was given to pcregrep with -v (invert match), it
545        did strange things, either producing crazy output, or crashing. It should,
546        of course, ignore a request for colour when reporting lines that do not
547        match.
549    4.  Another pcregrep bug caused similar problems if --colour was specified with
550        -M (multiline) and the pattern match finished with a line ending.
552    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
553        matched in multiline mode, the following line was shown as part of the
554        match. This seems wrong, so I have changed it.
556    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
557        the check for further matches in the same line (so they could be coloured)
558        to overrun the end of the current line. If another match was found, it was
559        incorrectly shown (and then shown again when found in the next line).
561    7.  If pcregrep was compiled under Windows, there was a reference to the
562        function pcregrep_exit() before it was defined. I am assuming this was
563        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
564        reported by a user. I've moved the definition above the reference.
567    Version 8.11 10-Dec-2010
568    ------------------------
570    1.  (*THEN) was not working properly if there were untried alternatives prior
571        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
572        backtracked to try for "b" instead of moving to the next alternative branch
573        at the same level (in this case, to look for "c"). The Perl documentation
574        is clear that when (*THEN) is backtracked onto, it goes to the "next
575        alternative in the innermost enclosing group".
577    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
578        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
579        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
580        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
581        (*THEN).
583    3.  If \s appeared in a character class, it removed the VT character from
584        the class, even if it had been included by some previous item, for example
585        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
586        of \s, but is part of the POSIX "space" class.)
588    4.  A partial match never returns an empty string (because you can always
589        match an empty string at the end of the subject); however the checking for
590        an empty string was starting at the "start of match" point. This has been
591        changed to the "earliest inspected character" point, because the returned
592        data for a partial match starts at this character. This means that, for
593        example, /(?<=abc)def/ gives a partial match for the subject "abc"
594        (previously it gave "no match").
596    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
597        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
598        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
599        has an implication that the given string is incomplete (because a partial
600        match is preferred over a full match). For this reason, these items now
601        give a partial match in this situation. [Aside: previously, the one case
602        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
603        match rather than a full match, which was wrong by the old rules, but is
604        now correct.]
606    6.  There was a bug in the handling of #-introduced comments, recognized when
607        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
608        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
609        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
610        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
611        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
612        places in pcre_compile().
614    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
615        comments when looking ahead for named forward references to subpatterns,
616        the only newline sequence it recognized was NL. It now handles newlines
617        according to the set newline convention.
619    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
620        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
621        cater for a lack of strerror(). These oversights have been fixed.
623    9.  Added --match-limit and --recursion-limit to pcregrep.
625    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
627    11. When the -o option was used, pcregrep was setting a return code of 1, even
628        when matches were found, and --line-buffered was not being honoured.
630    12. Added an optional parentheses number to the -o and --only-matching options
631        of pcregrep.
633    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
634        can match an empty string. The code to do it in pcretest and pcredemo
635        needed fixing:
637        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
638            only one byte after an empty string match just before CRLF (this case
639            just got forgotten; "any" and "anycrlf" were OK).
641        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
642            mode when an empty string match preceded an ASCII character followed by
643            a non-ASCII character. (The code for advancing by one character rather
644            than one byte was nonsense.)
646        (c) The pcredemo.c sample program did not have any code at all to handle
647            the cases when CRLF is a valid newline sequence.
649    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
650        as a starting offset was within the subject string. There is now a new
651        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
652        negative or greater than the length of the string. In order to test this,
653        pcretest is extended to allow the setting of negative starting offsets.
655    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
656        starting offset points to the beginning of a UTF-8 character was
657        unnecessarily clumsy. I tidied it up.
659    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
660        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
662    17. Nobody had reported that the --include_dir option, which was added in
663        release 7.7 should have been called --include-dir (hyphen, not underscore)
664        for compatibility with GNU grep. I have changed it to --include-dir, but
665        left --include_dir as an undocumented synonym, and the same for
666        --exclude-dir, though that is not available in GNU grep, at least as of
667        release 2.5.4.
669    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
670        characters from a string of bytes) have been redefined so as not to use
671        loops, in order to improve performance in some environments. At the same
672        time, I abstracted some of the common code into auxiliary macros to save
673        repetition (this should not affect the compiled code).
675    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
676        compile-time error is now given if \c is not followed by an ASCII
677        character, that is, a byte less than 128. (In EBCDIC mode, the code is
678        different, and any byte value is allowed.)
680    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
681        START_OPTIMIZE option, which is now allowed at compile time - but just
682        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
683        to pcregrep and other applications that have no direct access to PCRE
684        options. The new /Y option in pcretest sets this option when calling
685        pcre_compile().
687    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
688        back references. Groups containing recursive back references were forced to
689        be atomic by that change, but in the case of named groups, the amount of
690        memory required was incorrectly computed, leading to "Failed: internal
691        error: code overflow". This has been fixed.
693    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
694        pcretest.c, to avoid build problems in some Borland environments.
697    Version 8.10 25-Jun-2010
698    ------------------------
700    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
701        THEN.
703    2.  (*ACCEPT) was not working when inside an atomic group.
705    3.  Inside a character class, \B is treated as a literal by default, but
706        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
707        causes the error). The code is unchanged, but I tidied the documentation.
709    4.  Inside a character class, PCRE always treated \R and \X as literals,
710        whereas Perl faults them if its -w option is set. I have changed PCRE so
711        that it faults them when PCRE_EXTRA is set.
713    5.  Added support for \N, which always matches any character other than
714        newline. (It is the same as "." when PCRE_DOTALL is not set.)
716    6.  When compiling pcregrep with newer versions of gcc which may have
717        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
718        declared with attribute warn_unused_result" were given. Just casting the
719        result to (void) does not stop the warnings; a more elaborate fudge is
720        needed. I've used a macro to implement this.
722    7.  Minor change to pcretest.c to avoid a compiler warning.
724    8.  Added four artifical Unicode properties to help with an option to make
725        \s etc use properties (see next item). The new properties are: Xan
726        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
728    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
729        use Unicode properties. (*UCP) at the start of a pattern can be used to set
730        this option. Modified pcretest to add /W to test this facility. Added
731        REG_UCP to make it available via the POSIX interface.
733    10. Added --line-buffered to pcregrep.
735    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
736        studied, and the match started with a letter with a code point greater than
737        127 whose first byte was different to the first byte of the other case of
738        the letter, the other case of this starting letter was not recognized
739        (#976).
741    12. If a pattern that was studied started with a repeated Unicode property
742        test, for example, \p{Nd}+, there was the theoretical possibility of
743        setting up an incorrect bitmap of starting bytes, but fortunately it could
744        not have actually happened in practice until change 8 above was made (it
745        added property types that matched character-matching opcodes).
747    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
748        possible starting bytes for non-anchored patterns.
750    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
751        \R, and also a number of cases that involve Unicode properties, both
752        explicit and implicit when PCRE_UCP is set.
754    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
755        input, it could crash or give wrong results if characters with values
756        greater than 0xc0 were present in the subject string. (Detail: it assumed
757        UTF-8 input when processing these items.)
759    16. Added a lot of (int) casts to avoid compiler warnings in systems where
760        size_t is 64-bit (#991).
762    17. Added a check for running out of memory when PCRE is compiled with
763        --disable-stack-for-recursion (#990).
765    18. If the last data line in a file for pcretest does not have a newline on
766        the end, a newline was missing in the output.
768    19. The default pcre_chartables.c file recognizes only ASCII characters (values
769        less than 128) in its various bitmaps. However, there is a facility for
770        generating tables according to the current locale when PCRE is compiled. It
771        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
772        characters, are recognized by isspace() and therefore were getting set in
773        these tables, and indeed these tables seem to approximate to ISO 8859. This
774        caused a problem in UTF-8 mode when pcre_study() was used to create a list
775        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
776        which of course cannot start UTF-8 characters. I have changed the code so
777        that only real ASCII characters (less than 128) and the correct starting
778        bytes for UTF-8 encodings are set for characters greater than 127 when in
779        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
780        altogether.)
782    20. Added the /T option to pcretest so as to be able to run tests with non-
783        standard character tables, thus making it possible to include the tests
784        used for 19 above in the standard set of tests.
786    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
787        reference to a subpattern the other side of a comment that contains an
788        opening parenthesis caused either an internal compiling error, or a
789        reference to the wrong subpattern.
792    Version 8.02 19-Mar-2010
793    ------------------------
795    1.  The Unicode data tables have been updated to Unicode 5.2.0.
797    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
798        configured.
800    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
801        original author of that file, following a query about its status.
803    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
804        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
806    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
807        quantifier applied to a forward-referencing subroutine call, could compile
808        incorrect code or give the error "internal error: previously-checked
809        referenced subpattern not found".
811    6.  Both MS Visual Studio and Symbian OS have problems with initializing
812        variables to point to external functions. For these systems, therefore,
813        pcre_malloc etc. are now initialized to local functions that call the
814        relevant global functions.
816    7.  There were two entries missing in the vectors called coptable and poptable
817        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
818        I've fixed the data, and added a kludgy way of testing at compile time that
819        the lengths are correct (equal to the number of opcodes).
821    8.  Following on from 7, I added a similar kludge to check the length of the
822        eint vector in pcreposix.c.
824    9.  Error texts for pcre_compile() are held as one long string to avoid too
825        much relocation at load time. To find a text, the string is searched,
826        counting zeros. There was no check for running off the end of the string,
827        which could happen if a new error number was added without updating the
828        string.
830    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
832    11. \K was not working if it appeared in an atomic group or in a group that
833        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
834        \K is "not well defined" if used in an assertion. PCRE now accepts it if
835        the assertion is positive, but not if it is negative.
837    12. Change 11 fortuitously reduced the size of the stack frame used in the
838        "match()" function of pcre_exec.c by one pointer. Forthcoming
839        implementation of support for (*MARK) will need an extra pointer on the
840        stack; I have reserved it now, so that the stack frame size does not
841        decrease.
843    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
844        item in branch that calls a recursion is a subroutine call - as in the
845        second branch in the above example - was incorrectly given the compile-
846        time error "recursive call could loop indefinitely" because pcre_compile()
847        was not correctly checking the subroutine for matching a non-empty string.
849    14. The checks for overrunning compiling workspace could trigger after an
850        overrun had occurred. This is a "should never occur" error, but it can be
851        triggered by pathological patterns such as hundreds of nested parentheses.
852        The checks now trigger 100 bytes before the end of the workspace.
854    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
857    Version 8.01 19-Jan-2010
858    ------------------------
860    1.  If a pattern contained a conditional subpattern with only one branch (in
861        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
862        computed the wrong minimum data length (which is of course zero for such
863        subpatterns). This could cause incorrect "no match" results.
865    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
866        the pattern is reset in the first branch, pcre_compile() failed with
867        "internal error: code overflow at offset...". This happened only when
868        the reset was to the original external option setting. (An optimization
869        abstracts leading options settings into an external setting, which was the
870        cause of this.)
872    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
873        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
874        assertion pattern did not match (meaning that the assertion was true), it
875        was incorrectly treated as false if the SKIP had been reached during the
876        matching. This also applied to assertions used as conditions.
878    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
879        assertion subpattern, including such a pattern used as a condition,
880        unpredictable results occurred, instead of the error return
883    5.  The C++ GlobalReplace function was not working like Perl for the special
884        situation when an empty string is matched. It now does the fancy magic
885        stuff that is necessary.
887    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
888        removed. (These were left over from very, very early versions of PCRE.)
890    7.  Some cosmetic changes to the code to make life easier when compiling it
891        as part of something else:
893        (a) Change DEBUG to PCRE_DEBUG.
895        (b) In pcre_compile(), rename the member of the "branch_chain" structure
896            called "current" as "current_branch", to prevent a collision with the
897            Linux macro when compiled as a kernel module.
899        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
900            prevent a collision with the Linux macro when compiled as a kernel
901            module.
903    8.  In pcre_compile() there are some checks for integer overflows that used to
904        cast potentially large values to (double). This has been changed to that
905        when building, a check for int64_t is made, and if it is found, it is used
906        instead, thus avoiding the use of floating point arithmetic. (There is no
907        other use of FP in PCRE.) If int64_t is not found, the fallback is to
908        double.
910    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
911        2005 (difference between two addresses compared to an unsigned value).
913    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
914        custom one, because of the following reported problem in Windows:
916          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
917              under Win32.
918          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
919              therefore missing the function definition.
920          - The compiler thus generates a "C" signature for the test function.
921          - The linker fails to find the "C" function.
922          - PCRE fails to configure if asked to do so against libbz2.
924    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
925        messages were output:
927          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
928          rerunning libtoolize, to keep the correct libtool macros in-tree.
929          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
931        I have done both of these things.
933    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
934        most of the time, it *can* run out if it is given a pattern that contains a
935        runaway infinite recursion. I updated the discussion in the pcrestack man
936        page.
938    13. Now that we have gone to the x.xx style of version numbers, the minor
939        version may start with zero. Using 08 or 09 is a bad idea because users
940        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
941        interpreted as invalid octal numbers. I've updated the previous comment in
942        configure.ac, and also added a check that gives an error if 08 or 09 are
943        used.
945    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
946        causing partial matching to fail when the end of the subject matched \W
947        in a UTF-8 pattern where \W was quantified with a minimum of 3.
949    15. There were some discrepancies between the declarations in pcre_internal.h
950        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
951        their definitions. The declarations used "const uschar *" and the
952        definitions used USPTR. Even though USPTR is normally defined as "const
953        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
954        reported that: "This difference in casting confuses some C++ compilers, for
955        example, SunCC recognizes above declarations as different functions and
956        generates broken code for hbpcre." I have changed the declarations to use
957        USPTR.
959    16. GNU libtool is named differently on some systems. The autogen.sh script now
960        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
961        (FreeBSD).
963    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
964        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
965        comment: "Figure out how to create a longlong from a string: strtoll and
966        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
967        instance, but it only takes 2 args instead of 3!"
969    18. A subtle bug concerned with back references has been fixed by a change of
970        specification, with a corresponding code fix. A pattern such as
971        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
972        refers, was giving matches when it shouldn't. For example, xa=xaaa would
973        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
974        same bug. Such groups have to be quantified to be useful, or contained
975        inside another quantified group. (If there's no repetition, the reference
976        can never match.) The problem arises because, having left the group and
977        moved on to the rest of the pattern, a later failure that backtracks into
978        the group uses the captured value from the final iteration of the group
979        rather than the correct earlier one. I have fixed this in PCRE by forcing
980        any group that contains a reference to itself to be an atomic group; that
981        is, there cannot be any backtracking into it once it has completed. This is
982        similar to recursive and subroutine calls.
985    Version 8.00 19-Oct-09
986    ----------------------
988    1.  The table for translating pcre_compile() error codes into POSIX error codes
989        was out-of-date, and there was no check on the pcre_compile() error code
990        being within the table. This could lead to an OK return being given in
991        error.
993    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
994        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
995        in a Windows environment.
997    3.  The pcregrep --count option prints the count for each file even when it is
998        zero, as does GNU grep. However, pcregrep was also printing all files when
999        --files-with-matches was added. Now, when both options are given, it prints
1000        counts only for those files that have at least one match. (GNU grep just
1001        prints the file name in this circumstance, but including the count seems
1002        more useful - otherwise, why use --count?) Also ensured that the
1003        combination -clh just lists non-zero counts, with no names.
1005    4.  The long form of the pcregrep -F option was incorrectly implemented as
1006        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1007        but it seems right to fix it, and I didn't think it was worth preserving
1008        the old behaviour.
1010    5.  The command line items --regex=pattern and --regexp=pattern were not
1011        recognized by pcregrep, which required --regex pattern or --regexp pattern
1012        (with a space rather than an '='). The man page documented the '=' forms,
1013        which are compatible with GNU grep; these now work.
1015    6.  No libpcreposix.pc file was created for pkg-config; there was just
1016        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1018    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1019        when UCP support is not needed, by modifying the Python script that
1020        generates it from Unicode data files. This should not matter if the module
1021        is correctly used as a library, but I received one complaint about 50K of
1022        unwanted data. My guess is that the person linked everything into his
1023        program rather than using a library. Anyway, it does no harm.
1025    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1026        was a minimum greater than 1 for a wide character in a possessive
1027        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1028        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1029        character. Chaos in the form of incorrect output or a compiling loop could
1030        result.
1032    9.  The restrictions on what a pattern can contain when partial matching is
1033        requested for pcre_exec() have been removed. All patterns can now be
1034        partially matched by this function. In addition, if there are at least two
1035        slots in the offset vector, the offset of the earliest inspected character
1036        for the match and the offset of the end of the subject are set in them when
1037        PCRE_ERROR_PARTIAL is returned.
1039    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1040        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1041        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1042        and may be more useful for multi-segment matching.
1044    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1045        used to be given if ever the end of the subject was reached; now it is
1046        given only if matching could not proceed because another character was
1047        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1048        string "Z", which now yields "no match" instead of "partial match". In the
1049        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1050        final character ended with (*FAIL).
1052    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1053        if the pattern had a "must contain" character that was already found in the
1054        earlier partial match, unless partial matching was again requested. For
1055        example, with the pattern /dog.(body)?/, the "must contain" character is
1056        "g". If the first part-match was for the string "dog", restarting with
1057        "sbody" failed. This bug has been fixed.
1059    13. The string returned by pcre_dfa_exec() after a partial match has been
1060        changed so that it starts at the first inspected character rather than the
1061        first character of the match. This makes a difference only if the pattern
1062        starts with a lookbehind assertion or \b or \B (\K is not supported by
1063        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1064        matching functions compatible, and I think it's the right thing to do.
1066    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1067        so that the demonstration program is easily available in environments where
1068        PCRE has not been installed from source.
1070    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1071        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1072        library.
1074    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1075        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1076        is not the first non-POSIX option to be added. Clearly some people find
1077        these options useful.
1079    17. If a caller to the POSIX matching function regexec() passes a non-zero
1080        value for nmatch with a NULL value for pmatch, the value of
1081        nmatch is forced to zero.
1083    18. RunGrepTest did not have a test for the availability of the -u option of
1084        the diff command, as RunTest does. It now checks in the same way as
1085        RunTest, and also checks for the -b option.
1087    19. If an odd number of negated classes containing just a single character
1088        interposed, within parentheses, between a forward reference to a named
1089        subpattern and the definition of the subpattern, compilation crashed with
1090        an internal error, complaining that it could not find the referenced
1091        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1092        [The bug was that it was starting one character too far in when skipping
1093        over the character class, thus treating the ] as data rather than
1094        terminating the class. This meant it could skip too much.]
1096    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1097        /g option in pcretest when the pattern contains \K, which makes it possible
1098        to have an empty string match not at the start, even when the pattern is
1099        anchored. Updated pcretest and pcredemo to use this option.
1101    21. If the maximum number of capturing subpatterns in a recursion was greater
1102        than the maximum at the outer level, the higher number was returned, but
1103        with unset values at the outer level. The correct (outer level) value is
1104        now given.
1106    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1107        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1108        make it do so. The string so far is captured, making this feature
1109        compatible with Perl.
1111    23. The tests have been re-organized, adding tests 11 and 12, to make it
1112        possible to check the Perl 5.10 features against Perl 5.10.
1114    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1115        pattern matches a fixed length string. PCRE did not allow this; now it
1116        does. Neither allows recursion.
1118    25. I finally figured out how to implement a request to provide the minimum
1119        length of subject string that was needed in order to match a given pattern.
1120        (It was back references and recursion that I had previously got hung up
1121        on.) This code has now been added to pcre_study(); it finds a lower bound
1122        to the length of subject needed. It is not necessarily the greatest lower
1123        bound, but using it to avoid searching strings that are too short does give
1124        some useful speed-ups. The value is available to calling programs via
1125        pcre_fullinfo().
1127    26. While implementing 25, I discovered to my embarrassment that pcretest had
1128        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1129        study optimizations had never been tested with that matching function.
1130        Oops. What is worse, even when it was passed study data, there was a bug in
1131        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1132        were also very few tests of studied patterns with pcre_dfa_exec().
1134    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1135        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1136        on the other side of the coin, they are no longer allowed to have different
1137        names, because these cannot be distinguished in PCRE, and this has caused
1138        confusion. (This is a difference from Perl.)
1140    28. When duplicate subpattern names are present (necessarily with different
1141        numbers, as required by 27 above), and a test is made by name in a
1142        conditional pattern, either for a subpattern having been matched, or for
1143        recursion in such a pattern, all the associated numbered subpatterns are
1144        tested, and the overall condition is true if the condition is true for any
1145        one of them. This is the way Perl works, and is also more like the way
1146        testing by number works.
1149    Version 7.9 11-Apr-09
1150    ---------------------
1152    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1153        (pcretest), all targets were linked against these libraries. This included
1154        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1155        libraries. This caused unwanted dependencies to be created. This problem
1156        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1157        pcretest is linked with readline.
1159    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1160        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1161        moved outside it again, because FALSE and TRUE are already defined in AIX,
1162        but BOOL is not.
1164    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1165        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1167    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1168        hyphens) following file names and line numbers when outputting matching
1169        lines. This is not true; no spaces are inserted. I have also clarified the
1170        wording for the --colour (or --color) option.
1172    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1173        was not coloured; this is different to GNU grep, so I have changed it to be
1174        the same.
1176    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1177        each matching line was coloured. Now it goes on to look for further matches
1178        of any of the test patterns, which is the same behaviour as GNU grep.
1180    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1181        doesn't make sense to accept an empty string match in pcregrep, so I have
1182        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1183        seems to be how GNU grep behaves.
1185    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1186        start or after a newline", because the conditional assertion was not being
1187        correctly handled. The rule now is that both the assertion and what follows
1188        in the first alternative must satisfy the test.
1190    9.  If auto-callout was enabled in a pattern with a conditional group whose
1191        condition was an assertion, PCRE could crash during matching, both with
1192        pcre_exec() and pcre_dfa_exec().
1194    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1195        used for matching.
1197    11. Unicode property support in character classes was not working for
1198        characters (bytes) greater than 127 when not in UTF-8 mode.
1200    12. Added the -M command line option to pcretest.
1202    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1204    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1206    16. Added comments and documentation about mis-use of no_arg in the C++
1207        wrapper.
1209    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1210        from Martin Jerabek that uses macro names for all relevant character and
1211        string constants.
1213    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1214        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1215        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1216        these, but not everybody uses configure.
1218    19. A conditional group that had only one branch was not being correctly
1219        recognized as an item that could match an empty string. This meant that an
1220        enclosing group might also not be so recognized, causing infinite looping
1221        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1222        with the subject "ab", where knowledge that the repeated group can match
1223        nothing is needed in order to break the loop.
1225    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1226        exec(), but without supplying a callout function, matching went wrong.
1228    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1229        leak if the size of the offset vector was greater than 30. When the vector
1230        is smaller, the saved offsets during recursion go onto a local stack
1231        vector, but for larger vectors malloc() is used. It was failing to free
1232        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1233        error, in fact).
1235    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1236        heapframe that is used only when UTF-8 support is enabled. This caused no
1237        problem, but was untidy.
1239    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1240        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1241        included within another project.
1243    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1244        slightly modified by me:
1246          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1247              not building pcregrep.
1249          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1250              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1252    25. Forward references, both numeric and by name, in patterns that made use of
1253        duplicate group numbers, could behave incorrectly or give incorrect errors,
1254        because when scanning forward to find the reference group, PCRE was not
1255        taking into account the duplicate group numbers. A pattern such as
1256        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1258    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1259        the feature of a custom pointer more persuasive (as requested by a user).
1261    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1262        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1263        pre-defined.
1265    28. Added support for (*UTF8) at the start of a pattern.
1267    29. Arrange for flags added by the "release type" setting in CMake to be shown
1268        in the configuration summary.
1271    Version 7.8 05-Sep-08
1272    ---------------------
1274    1.  Replaced UCP searching code with optimized version as implemented for Ad
1275        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1276        stage table and inline lookup instead of a function, giving speed ups of 2
1277        to 5 times on some simple patterns that I tested. Permission was given to
1278        distribute the MultiStage2.py script that generates the tables (it's not in
1279        the tarball, but is in the Subversion repository).
1281    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1282        scripts.
1284    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1285        a group with a zero qualifier. The result of the study could be incorrect,
1286        or the function might crash, depending on the pattern.
1288    4.  Caseless matching was not working for non-ASCII characters in back
1289        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1290        It now works when Unicode Property Support is available.
1292    5.  In pcretest, an escape such as \x{de} in the data was always generating
1293        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1294        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1295        truncation.
1297    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1299    7.  Added two (int) casts to pcregrep when printing the difference of two
1300        pointers, in case they are 64-bit values.
1302    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1303        test 2 if it fails.
1305    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1306        and a #define of that name to empty if it is not externally set. This is to
1307        allow users of MSVC to set it if necessary.
1309    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1310        the convenience functions in the pcre_get.c source file.
1312    11. An option change at the start of a pattern that had top-level alternatives
1313        could cause overwriting and/or a crash. This command provoked a crash in
1314        some environments:
1316          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1318        This potential security problem was recorded as CVE-2008-2371.
1320    12. For a pattern where the match had to start at the beginning or immediately
1321        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1322        pcre_dfa_exec() could read past the end of the passed subject if there was
1323        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1324        pcretest so that it places the subject at the end of its malloc-ed buffer.
1326    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1327        exec() might read past the end of the data buffer in UTF-8 mode.
1329    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1330        the data contained the byte 0x85 as part of a UTF-8 character within its
1331        first line. This applied both to normal and DFA matching.
1333    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1334        /^[^d]*?$/8 failed to match "abc".
1336    16. Added a missing copyright notice to pcrecpp_internal.h.
1338    17. Make it more clear in the documentation that values returned from
1339        pcre_exec() in ovector are byte offsets, not character counts.
1341    18. Tidied a few places to stop certain compilers from issuing warnings.
1343    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1344        supplied by Stefan Weber. I made a further small update for 7.8 because
1345        there is a change of source arrangements: the pcre_searchfuncs.c module is
1346        replaced by pcre_ucd.c.
1349    Version 7.7 07-May-08
1350    ---------------------
1352    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1353        a string to a long long, pretend we don't even have a long long." This is
1354        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1356    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1357        pre-7.6 versions, which defined a global no_arg variable instead of putting
1358        it in the RE class. (See also #8 below.)
1360    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1361        Lopes.
1363    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1365        (1) The include/exclude patterns were being applied to the whole pathnames
1366            of files, instead of just to the final components.
1368        (2) If there was more than one level of directory, the subdirectories were
1369            skipped unless they satisfied the include/exclude conditions. This is
1370            inconsistent with GNU grep (and could even be seen as contrary to the
1371            pcregrep specification - which I improved to make it absolutely clear).
1372            The action now is always to scan all levels of directory, and just
1373            apply the include/exclude patterns to regular files.
1375    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1376        --exclude_dir in the tests to avoid scanning .svn directories.
1378    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1379        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1380        doesn't support NULs in patterns.
1382    7.  Added some missing "const"s to declarations of static tables in
1383        pcre_compile.c and pcre_dfa_exec.c.
1385    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1386        caused by fix #2  above. (Subsequently also a second patch to fix the
1387        first patch. And a third patch - this was a messy problem.)
1389    9.  Applied Craig's patch to remove the use of push_back().
1391    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1392        matching function regexec().
1394    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1395        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1396        references. PCRE supports relative numbers with this syntax (I don't think
1397        Oniguruma does).
1399    12. Previously, a group with a zero repeat such as (...){0} was completely
1400        omitted from the compiled regex. However, this means that if the group
1401        was called as a subroutine from elsewhere in the pattern, things went wrong
1402        (an internal error was given). Such groups are now left in the compiled
1403        pattern, with a new opcode that causes them to be skipped at execution
1404        time.
1406    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1407        to the way PCRE behaves:
1409        (a) A lone ] character is dis-allowed (Perl treats it as data).
1411        (b) A back reference to an unmatched subpattern matches an empty string
1412            (Perl fails the current match path).
1414        (c) A data ] in a character class must be notated as \] because if the
1415            first data character in a class is ], it defines an empty class. (In
1416            Perl it is not possible to have an empty class.) The empty class []
1417            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1418            The negative empty class [^] matches any one character, independently
1419            of the DOTALL setting.
1421    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1422        non-existent subpattern following a character class starting with ']' and
1423        containing () gave an internal compiling error instead of "reference to
1424        non-existent subpattern". Fortunately, when the pattern did exist, the
1425        compiled code was correct. (When scanning forwards to check for the
1426        existencd of the subpattern, it was treating the data ']' as terminating
1427        the class, so got the count wrong. When actually compiling, the reference
1428        was subsequently set up correctly.)
1430    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1431        it was being rejected as not supported by pcre_dfa_exec(), even though
1432        other assertions are supported. I have made pcre_dfa_exec() support
1433        (*FAIL).
1435    16. The implementation of 13c above involved the invention of a new opcode,
1436        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1437        cannot be changed at match time, I realized I could make a small
1438        improvement to matching performance by compiling OP_ALLANY instead of
1439        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1440        on the OP_ANY path.
1442    17. Compiling pcretest on Windows with readline support failed without the
1443        following two fixes: (1) Make the unistd.h include conditional on
1444        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1446    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1447        ncurses library to be included for pcretest when ReadLine support is
1448        requested, but also to allow for it to be overridden. This patch came from
1449        Daniel Bergström.
1451    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1452        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1453        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1454        spotting this.
1457    Version 7.6 28-Jan-08
1458    ---------------------
1460    1.  A character class containing a very large number of characters with
1461        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1462        overflow.
1464    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1465        HAVE_LONG_LONG is not defined.
1467    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1468        bring them up to date and include new features. This patch includes:
1470        - Fixed PH's badly added libz and libbz2 support.
1471        - Fixed a problem with static linking.
1472        - Added pcredemo. [But later removed - see 7 below.]
1473        - Fixed dftables problem and added an option.
1474        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1475            HAVE_LONG_LONG.
1476        - Added readline support for pcretest.
1477        - Added an listing of the option settings after cmake has run.
1479    4.  A user submitted a patch to Makefile that makes it easy to create
1480        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1481        Makefile.am that cause it to include this special target, without
1482        affecting anything else. Note that the same mingw target plus all
1483        the other distribution libraries and programs are now supported
1484        when configuring with CMake (see 6 below) instead of with
1485        Configure/Make.
1487    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1488        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1489        exported in the Windows port". It has not yet been confirmed that the patch
1490        solves the problem, but it does no harm.
1492    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1493        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1494        with CMake, and also correct the comment about stack recursion.
1496    7.  Remove the automatic building of pcredemo from the ./configure system and
1497        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1498        of a program that users should build themselves after PCRE is installed, so
1499        building it automatically is not really right. What is more, it gave
1500        trouble in some build environments.
1502    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1505    Version 7.5 10-Jan-08
1506    ---------------------
1508    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1509        values in parens when parsing an RE using the C++ wrapper."
1511    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1512        Characters greater than 255 were excluded from the class instead of being
1513        included.
1515    3.  The same bug as (2) above applied to negated POSIX classes such as
1516        [:^space:].
1518    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1519        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1520        I have changed it.
1522    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1523        first named subpattern) and a construct such as (?&a) would reference the
1524        first named subpattern whose name started with "a" (in other words, the
1525        length check was missing). Both these problems are fixed. "Subpattern name
1526        expected" is now given for (?&) (a zero-length name), and this patch also
1527        makes it give the same error for \k'' (previously it complained that that
1528        was a reference to a non-existent subpattern).
1530    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1531        this is right because (?- can be followed by option settings as well as by
1532        digits. I have, however, made the messages clearer.
1534    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1535        than the number used in the conditional) now cause a compile-time error.
1536        This is actually not compatible with Perl, which accepts such patterns, but
1537        treats the conditional as always being FALSE (as PCRE used to), but it
1538        seems to me that giving a diagnostic is better.
1540    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1541        and messages.
1543    9.  Fix two occurrences of "backslash" in comments that should have been
1544        "backspace".
1546    10. Remove two redundant lines of code that can never be obeyed (their function
1547        was moved elsewhere).
1549    11. The program that makes PCRE's Unicode character property table had a bug
1550        which caused it to generate incorrect table entries for sequences of
1551        characters that have the same character type, but are in different scripts.
1552        It amalgamated them into a single range, with the script of the first of
1553        them. In other words, some characters were in the wrong script. There were
1554        thirteen such cases, affecting characters in the following ranges:
1556          U+002b0 - U+002c1
1557          U+0060c - U+0060d
1558          U+0061e - U+00612
1559          U+0064b - U+0065e
1560          U+0074d - U+0076d
1561          U+01800 - U+01805
1562          U+01d00 - U+01d77
1563          U+01d9b - U+01dbf
1564          U+0200b - U+0200f
1565          U+030fc - U+030fe
1566          U+03260 - U+0327f
1567          U+0fb46 - U+0fbb1
1568          U+10450 - U+1049d
1570    12. The -o option (show only the matching part of a line) for pcregrep was not
1571        compatible with GNU grep in that, if there was more than one match in a
1572        line, it showed only the first of them. It now behaves in the same way as
1573        GNU grep.
1575    13. If the -o and -v options were combined for pcregrep, it printed a blank
1576        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1577        does the same. The return code can be used to tell if there were any
1578        non-matching lines.
1580    14. Added --file-offsets and --line-offsets to pcregrep.
1582    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1583        infinitely looping recursion. The bug was that positive lookaheads were not
1584        being skipped when checking for a possible empty match (negative lookaheads
1585        and both kinds of lookbehind were skipped).
1587    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1588        inclusion of <windows.h> to before rather than after the definition of
1589        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1591    17. Specifying a possessive quantifier with a specific limit for a Unicode
1592        character property caused pcre_compile() to compile bad code, which led at
1593        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1594        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1595        caused the error; without that there was no problem.
1597    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1599    19. Added --enable-pcretest-libreadline.
1601    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1602        RE::GlobalReplace(). As a result, the number of replacements returned was
1603        double what it should be. I removed one of the increments, but Craig sent a
1604        later patch that removed the other one (the right fix) and added unit tests
1605        that check the return values (which was not done before).
1607    21. Several CMake things:
1609        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1610            the names libpcre and libpcreposix, not just pcre and pcreposix.
1612        (2) The above change means that pcretest and pcregrep are now correctly
1613            linked with the newly-built libraries, not previously installed ones.
1617    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1618        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1619        UTF-8 newline character). The key issue is that the pattern starts .*;
1620        this means that the match must be either at the beginning, or after a
1621        newline. The bug was in the code for advancing after a failed match and
1622        checking that the new position followed a newline. It was not taking
1623        account of UTF-8 characters correctly.
1625    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1626        character classes. PCRE was not treating the sequence [:...:] as a
1627        character class unless the ... were all letters. Perl, however, seems to
1628        allow any characters between [: and :], though of course it rejects as
1629        unknown any "names" that contain non-letters, because all the known class
1630        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1631        for example, whereas PCRE did not - it did not recognize a POSIX character
1632        class. This seemed a bit dangerous, so the code has been changed to be
1633        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1634        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1635        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1636        Perl does, and where it didn't before.
1638    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1639        Windows environments %n is disabled by default.
1642    Version 7.4 21-Sep-07
1643    ---------------------
1645    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1646        means that a class such as [\s] counted as "explicit reference to CR or
1647        LF". That isn't really right - the whole point of the change was to try to
1648        help when there was an actual mention of one of the two characters. So now
1649        the change happens only if \r or \n (or a literal CR or LF) character is
1650        encountered.
1652    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1653        of both had grown to the point where there were only 3 bits left.
1654        Fortunately, there was spare space in the data structure, and so I have
1655        moved the internal flags into a new 16-bit field to free up more option
1656        bits.
1658    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1659        but did not set the internal JCHANGED flag - either of these is enough to
1660        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1661        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1662        start sets both bits.
1664    4.  Added options (at build time, compile time, exec time) to change \R from
1665        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1667    5.  doc/pcresyntax.html was missing from the distribution.
1669    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1670        compatibility, even though it is no longer used.
1672    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1673        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1674        windows.h file is present (where different names are used). [This was
1675        reversed later after testing - see 16 below.]
1677    8.  Changed all #include <config.h> to #include "config.h". There were also
1678        some further <pcre.h> cases that I changed to "pcre.h".
1680    9.  When pcregrep was used with the --colour option, it missed the line ending
1681        sequence off the lines that it output.
1683    10. It was pointed out to me that arrays of string pointers cause lots of
1684        relocations when a shared library is dynamically loaded. A technique of
1685        using a single long string with a table of offsets can drastically reduce
1686        these. I have refactored PCRE in four places to do this. The result is
1687        dramatic:
1689          Originally:                          290
1690          After changing UCP table:            187
1691          After changing error message table:   43
1692          After changing table of "verbs"       36
1693          After changing table of Posix names   22
1695        Thanks to the folks working on Gregex for glib for this insight.
1697    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1698        unicode-properties was also set.
1700    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1702    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1703        checked only for CRLF.
1705    14. Added casts to pcretest.c to avoid compiler warnings.
1707    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1709    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1710        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1711        entirely. This removes changes made in 7 above.
1713    17. The CMake files have been updated, and there is now more information about
1714        building with CMake in the NON-UNIX-USE document.
1717    Version 7.3 28-Aug-07
1718    ---------------------
1720     1. In the rejigging of the build system that eventually resulted in 7.1, the
1721        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1722        brackets there is not right, since it causes compilers to look for an
1723        installed pcre.h, not the version that is in the source that is being
1724        compiled (which of course may be different). I have changed it back to:
1726          #include "pcre.h"
1728        I have a vague recollection that the change was concerned with compiling in
1729        different directories, but in the new build system, that is taken care of
1730        by the VPATH setting the Makefile.
1732     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1733        when the subject happened to end in the byte 0x85 (e.g. if the last
1734        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1735        characters but of course it shouldn't be taken as a newline when it is part
1736        of another character. The bug was that, for an unlimited repeat of . in
1737        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1738        characters when looking for a newline.
1740     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1742     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1743        in debug output.
1745     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1746        long printing in the pcrecpp unittest when running under MinGW.
1748     6. ESC_K was left out of the EBCDIC table.
1750     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1751        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1752        limit also applies to "virtual nesting" when a pattern is recursive, and in
1753        this case 1000 isn't so big. I have been able to remove this limit at the
1754        expense of backing off one optimization in certain circumstances. Normally,
1755        when pcre_exec() would call its internal match() function recursively and
1756        immediately return the result unconditionally, it uses a "tail recursion"
1757        feature to save stack. However, when a subpattern that can match an empty
1758        string has an unlimited repetition quantifier, it no longer makes this
1759        optimization. That gives it a stack frame in which to save the data for
1760        checking that an empty string has been matched. Previously this was taken
1761        from the 1000-entry workspace that had been reserved. So now there is no
1762        explicit limit, but more stack is used.
1764     8. Applied Daniel's patches to solve problems with the import/export magic
1765        syntax that is required for Windows, and which was going wrong for the
1766        pcreposix and pcrecpp parts of the library. These were overlooked when this
1767        problem was solved for the main library.
1769     9. There were some crude static tests to avoid integer overflow when computing
1770        the size of patterns that contain repeated groups with explicit upper
1771        limits. As the maximum quantifier is 65535, the maximum group length was
1772        set at 30,000 so that the product of these two numbers did not overflow a
1773        32-bit integer. However, it turns out that people want to use groups that
1774        are longer than 30,000 bytes (though not repeat them that many times).
1775        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1776        made it possible to implement the integer overflow checks in a much more
1777        dynamic way, which I have now done. The artificial limitation on group
1778        length has been removed - we now have only the limit on the total length of
1779        the compiled pattern, which depends on the LINK_SIZE setting.
1781    10. Fixed a bug in the documentation for get/copy named substring when
1782        duplicate names are permitted. If none of the named substrings are set, the
1783        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1784        empty string.
1786    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1787        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1788        because the ] is interpreted as the first data character and the
1789        terminating ] is not found. PCRE has been made compatible with Perl in this
1790        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1791        cause memory overwriting.
1793    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1794        string has been matched (to stop an infinite loop). It was not recognizing
1795        a conditional subpattern that could match an empty string if that
1796        subpattern was within another subpattern. For example, it looped when
1797        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1798        condition was not nested. This bug has been fixed.
1800    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1801        past the start of the subject in the presence of bytes with the top bit
1802        set, for example "\x8aBCD".
1804    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1805        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1807    14. Optimized (?!) to (*FAIL).
1809    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1810        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1811        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1812        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1813        does: it's just the validity check that is more restrictive.
1815    16. Inserted checks for integer overflows during escape sequence (backslash)
1816        processing, and also fixed erroneous offset values for syntax errors during
1817        backslash processing.
1819    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1820        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1822    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1823        caused an overrun.
1825    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1826        something other than just ASCII characters) inside a group that had an
1827        unlimited repeat caused a loop at compile time (while checking to see
1828        whether the group could match an empty string).
1830    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1831        [\P{Any}] did so. (Error in the code for printing property names.)
1833    21. An orphan \E inside a character class could cause a crash.
1835    22. A repeated capturing bracket such as (A)? could cause a wild memory
1836        reference during compilation.
1838    23. There are several functions in pcre_compile() that scan along a compiled
1839        expression for various reasons (e.g. to see if it's fixed length for look
1840        behind). There were bugs in these functions when a repeated \p or \P was
1841        present in the pattern. These operators have additional parameters compared
1842        with \d, etc, and these were not being taken into account when moving along
1843        the compiled data. Specifically:
1845        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1846            length.
1848        (b) An item such as \pL+ within a repeated group could cause crashes or
1849            loops.
1851        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1852            "reference to non-existent subpattern" error.
1854        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1856    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1857        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1859    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1861    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1862        character were causing crashes (broken optimization).
1864    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1865        \p or \P) caused a compile-time loop.
1867    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1868        break. For example, the unstudied pattern [\r\n]A does not match the string
1869        "\r\nA" because change 7.0/46 below moves the current point on by two
1870        characters after failing to match at the start. However, the pattern \nA
1871        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1872        the same is true. There doesn't seem any very clean way out of this, but
1873        what I have chosen to do makes the common cases work: PCRE now takes note
1874        of whether there can be an explicit match for \r or \n anywhere in the
1875        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1876        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1877        pattern has explicit CR or LF references.
1879    29. Added (*CR) etc for changing newline setting at start of pattern.
1882    Version 7.2 19-Jun-07
1883    ---------------------
1885     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1886        which is apparently normally available under Windows.
1888     2. Re-jig the pcregrep tests with different newline settings in an attempt
1889        to make them independent of the local environment's newline setting.
1891     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1893     4. Some of the "internals" tests were previously cut out when the link size
1894        was not 2, because the output contained actual offsets. The recent new
1895        "Z" feature of pcretest means that these can be cut out, making the tests
1896        usable with all link sizes.
1898     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1899        stack recursion. This gives a massive performance boost under BSD, but just
1900        a small improvement under Linux. However, it saves one field in the frame
1901        in all cases.
1903     6. Added more features from the forthcoming Perl 5.10:
1905        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1906            recursion call. It refers to the nth most recently opened parentheses.
1908        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1909            to be opened parentheses.
1911        (c) Conditions that refer to capturing parentheses can be specified
1912            relatively, for example, (?(-2)... or (?(+3)...
1914        (d) \K resets the start of the current match so that everything before
1915            is not part of it.
1917        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1919        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1920            reference syntax.
1922        (g) (?| introduces a group in which the numbering of parentheses in each
1923            alternative starts with the same number.
1925        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1927     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1930     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1931        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1932        for detecting groups that can match an empty string.
1934     9. A pattern with a very large number of alternatives (more than several
1935        hundred) was running out of internal workspace during the pre-compile
1936        phase, where pcre_compile() figures out how much memory will be needed. A
1937        bit of new cunning has reduced the workspace needed for groups with
1938        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1939        workspace instead of running out of the 4096 that are available.
1941    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1943    11. Applied patch from Google to remove an optimization that didn't quite work.
1944        The report of the bug said:
1946          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1947          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1948          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1950    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1951        it matched the wrong number of bytes.
1954    Version 7.1 24-Apr-07
1955  ---------------------  ---------------------
1957   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 136  Version 7.1 12-Mar-07 Line 2086  Version 7.1 12-Mar-07
2086      string at the end of a line did not allow for this case. They now check for      string at the end of a line did not allow for this case. They now check for
2087      it specially.      it specially.
2089    20. pcretest is supposed to handle patterns and data of any length, by
2090        extending its buffers when necessary. It was getting this wrong when the
2091        buffer for a data line had to be extended.
2093    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2094        CRLF as a newline sequence.
2096    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2097        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2098        I have nevertheless tidied it up.
2100    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2102    24. Added a man page for pcre-config.
2105  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
2106  ---------------------  ---------------------

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