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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.1 05-Mar-07  Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
17    Version 8.20 21-Oct-2011
18    ------------------------
20    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
21        a POSIX class. After further experiments with Perl, which convinced me that
22        Perl has bugs and confusions, a closing square bracket is no longer allowed
23        in a POSIX name. This bug also affected patterns with classes that started
24        with full stops.
26    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
27        captured substring, but while checking the failing first alternative,
28        substring 1 is temporarily captured. If the output vector supplied to
29        pcre_exec() was not big enough for this capture, the yield of the function
30        was still zero ("insufficient space for captured substrings"). This cannot
31        be totally fixed without adding another stack variable, which seems a lot
32        of expense for a edge case. However, I have improved the situation in cases
33        such as /(a)(b)x|abc/ matched against "abc", where the return code
34        indicates that fewer than the maximum number of slots in the ovector have
35        been set.
37    3.  Related to (2) above: when there are more back references in a pattern than
38        slots in the output vector, pcre_exec() uses temporary memory during
39        matching, and copies in the captures as far as possible afterwards. It was
40        using the entire output vector, but this conflicts with the specification
41        that only 2/3 is used for passing back captured substrings. Now it uses
42        only the first 2/3, for compatibility. This is, of course, another edge
43        case.
45    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
46        main code base, and can be used by building with --enable-jit. When this is
47        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
48        runtime --no-jit option is given.
50    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
51        ovector, the return from the function was zero, implying that there were
52        other matches that did not fit. The correct "exactly full" value is now
53        returned.
55    6.  If a subpattern that was called recursively or as a subroutine contained
56        (*PRUNE) or any other control that caused it to give a non-standard return,
57        invalid errors such as "Error -26 (nested recursion at the same subject
58        position)" or even infinite loops could occur.
60    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
61        computing the minimum length on reaching *ACCEPT, and so ended up with the
62        wrong value of 1 rather than 0. Further investigation indicates that
63        computing a minimum subject length in the presence of *ACCEPT is difficult
64        (think back references, subroutine calls), and so I have changed the code
65        so that no minimum is registered for a pattern that contains *ACCEPT.
67    8.  If (*THEN) was present in the first (true) branch of a conditional group,
68        it was not handled as intended. [But see 16 below.]
70    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
71        Sheri Pierce.
73    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
74        the first byte in a match must be "a".
76    11. Change 17 for 8.13 increased the recursion depth for patterns like
77        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
78        pattern contains any instances of (*THEN). If it does not, the old
79        optimizations are restored. It would be nice to do this on a per-group
80        basis, but at the moment that is not feasible.
82    12. In some environments, the output of pcretest -C is CRLF terminated. This
83        broke RunTest's code that checks for the link size. A single white space
84        character after the value is now allowed for.
86    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
87        For "fr", it uses the Windows-specific input and output files.
89    14. If (*THEN) appeared in a group that was called recursively or as a
90        subroutine, it did not work as intended. [But see next item.]
92    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
93        pattern fragments (but not containing any | characters). If A and B are
94        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
95        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
96        D. In other words, Perl considers parentheses that do not contain any |
97        characters to be part of a surrounding alternative, whereas PCRE was
98        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
99        differently. PCRE now behaves in the same way as Perl, except in the case
100        of subroutine/recursion calls such as (?1) which have in any case always
101        been different (but PCRE had them first :-).
103    16. Related to 15 above: Perl does not treat the | in a conditional group as
104        creating alternatives. Such a group is treated in the same way as an
105        ordinary group without any | characters when processing (*THEN). PCRE has
106        been changed to match Perl's behaviour.
108    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
109        RunGrepTest script failed.
111    18. Change 22 for version 13 caused atomic groups to use more stack. This is
112        inevitable for groups that contain captures, but it can lead to a lot of
113        stack use in large patterns. The old behaviour has been restored for atomic
114        groups that do not contain any capturing parentheses.
116    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
117        suppress the check for a minimum subject length at run time. (If it was
118        given to pcre_exec() or pcre_dfa_exec() it did work.)
120    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
121        fail to work when decoding hex characters in data strings in EBCDIC
122        environments.
124    21. It appears that in at least one Mac OS environment, the isxdigit() function
125        is implemented as a macro that evaluates to its argument more than once,
126        contravening the C 90 Standard (I haven't checked a later standard). There
127        was an instance in pcretest which caused it to go wrong when processing
128        \x{...} escapes in subject strings. The has been rewritten to avoid using
129        things like p++ in the argument of isxdigit().
132    Version 8.13 16-Aug-2011
133    ------------------------
135    1.  The Unicode data tables have been updated to Unicode 6.0.0.
137    2.  Two minor typos in pcre_internal.h have been fixed.
139    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
140        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
141        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
143    4.  There were a number of related bugs in the code for matching backrefences
144        caselessly in UTF-8 mode when codes for the characters concerned were
145        different numbers of bytes. For example, U+023A and U+2C65 are an upper
146        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
147        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
148        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
149        2-byte code at the end of the subject (it thought there wasn't enough data
150        left).
152    5.  Comprehensive information about what went wrong is now returned by
153        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
154        as the output vector has at least 2 elements. The offset of the start of
155        the failing character and a reason code are placed in the vector.
157    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
158        now returned is for the first byte of the failing character, instead of the
159        last byte inspected. This is an incompatible change, but I hope it is small
160        enough not to be a problem. It makes the returned offset consistent with
161        pcre_exec() and pcre_dfa_exec().
163    7.  pcretest now gives a text phrase as well as the error number when
164        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
165        failure, the offset and reason code are output.
167    8.  When \R was used with a maximizing quantifier it failed to skip backwards
168        over a \r\n pair if the subsequent match failed. Instead, it just skipped
169        back over a single character (\n). This seems wrong (because it treated the
170        two characters as a single entity when going forwards), conflicts with the
171        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
172        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
173        has been changed.
175    9.  Some internal refactoring has changed the processing so that the handling
176        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
177        time (the PCRE_DOTALL option was changed this way some time ago: version
178        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
179        which was always a bit of a fudge. It also means that there is one less
180        argument for the match() function, which reduces its stack requirements
181        slightly. This change also fixes an incompatibility with Perl: the pattern
182        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
184    10. More internal refactoring has drastically reduced the number of recursive
185        calls to match() for possessively repeated groups such as (abc)++ when
186        using pcre_exec().
188    11. While implementing 10, a number of bugs in the handling of groups were
189        discovered and fixed:
191        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
192        (a|)*(?1) gave a compile-time internal error.
193        ((a|)+)+  did not notice that the outer group could match an empty string.
194        (^a|^)+   was not marked as anchored.
195        (.*a|.*)+ was not marked as matching at start or after a newline.
197    12. Yet more internal refactoring has removed another argument from the match()
198        function. Special calls to this function are now indicated by setting a
199        value in a variable in the "match data" data block.
201    13. Be more explicit in pcre_study() instead of relying on "default" for
202        opcodes that mean there is no starting character; this means that when new
203        ones are added and accidentally left out of pcre_study(), testing should
204        pick them up.
206    14. The -s option of pcretest has been documented for ages as being an old
207        synonym of -m (show memory usage). I have changed it to mean "force study
208        for every regex", that is, assume /S for every regex. This is similar to -i
209        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
210        using it. It makes it easier to run collections of tests with and without
211        study enabled, and thereby test pcre_study() more easily. All the standard
212        tests are now run with and without -s (but some patterns can be marked as
213        "never study" - see 20 below).
215    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
216        restoration of the capturing data to the outer values was not happening
217        correctly.
219    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
220        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
221        pattern had matched an empty string, and so incorrectly returned a no
222        match.
224    17. There was optimizing code for the last branch of non-capturing parentheses,
225        and also for the obeyed branch of a conditional subexpression, which used
226        tail recursion to cut down on stack usage. Unfortunately, now that there is
227        the possibility of (*THEN) occurring in these branches, tail recursion is
228        no longer possible because the return has to be checked for (*THEN). These
229        two optimizations have therefore been removed. [But see 8.20/11 above.]
231    18. If a pattern containing \R was studied, it was assumed that \R always
232        matched two bytes, thus causing the minimum subject length to be
233        incorrectly computed because \R can also match just one byte.
235    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
236        was incorrectly computed.
238    20. If /S is present twice on a test pattern in pcretest input, it now
239        *disables* studying, thereby overriding the use of -s on the command line
240        (see 14 above). This is necessary for one or two tests to keep the output
241        identical in both cases.
243    21. When (*ACCEPT) was used in an assertion that matched an empty string and
244        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
246    22. When an atomic group that contained a capturing parenthesis was
247        successfully matched, but the branch in which it appeared failed, the
248        capturing was not being forgotten if a higher numbered group was later
249        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
250        group 1 to "a", when in fact it should be unset. This applied to multi-
251        branched capturing and non-capturing groups, repeated or not, and also to
252        positive assertions (capturing in negative assertions does not happen
253        in PCRE) and also to nested atomic groups.
255    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
256        subject after a captured substring, to make it easier to tell which of a
257        number of identical substrings has been captured.
259    24. The way atomic groups are processed by pcre_exec() has been changed so that
260        if they are repeated, backtracking one repetition now resets captured
261        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
262        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
263        "aaa". Previously, it would have been "a". As part of this code
264        refactoring, the way recursive calls are handled has also been changed.
266    25. If an assertion condition captured any substrings, they were not passed
267        back unless some other capturing happened later. For example, if
268        (?(?=(a))a) was matched against "a", no capturing was returned.
270    26. When studying a pattern that contained subroutine calls or assertions,
271        the code for finding the minimum length of a possible match was handling
272        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
273        group 1 called group 2 while simultaneously a separate group 2 called group
274        1). A stack overflow occurred in this case. I have fixed this by limiting
275        the recursion depth to 10.
277    27. Updated RunTest.bat in the distribution to the version supplied by Tom
278        Fortmann. This supports explicit test numbers on the command line, and has
279        argument validation and error reporting.
281    28. An instance of \X with an unlimited repeat could fail if at any point the
282        first character it looked at was a mark character.
284    29. Some minor code refactoring concerning Unicode properties and scripts
285        should reduce the stack requirement of match() slightly.
287    30. Added the '=' option to pcretest to check the setting of unused capturing
288        slots at the end of the pattern, which are documented as being -1, but are
289        not included in the return count.
291    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
292        compiled something random. Now it gives a compile-time error (as does
293        Perl).
295    32. A *MARK encountered during the processing of a positive assertion is now
296        recorded and passed back (compatible with Perl).
298    33. If --only-matching or --colour was set on a pcregrep call whose pattern
299        had alternative anchored branches, the search for a second match in a line
300        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
301        matched the line "0102" twice. The same bug affected patterns that started
302        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
303        twice.
305    34. Previously, PCRE did not allow quantification of assertions. However, Perl
306        does, and because of capturing effects, quantifying parenthesized
307        assertions may at times be useful. Quantifiers are now allowed for
308        parenthesized assertions.
310    35. A minor code tidy in pcre_compile() when checking options for \R usage.
312    36. \g was being checked for fancy things in a character class, when it should
313        just be a literal "g".
315    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
316        appearance of a nested POSIX class supersedes an apparent external class.
317        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
318        unescaped square brackets may also appear as part of class names. For
319        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
320        more like Perl. (But see 8.20/1 above.)
322    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
323        was because it thought it was \N{name}, which is not supported).
325    39. Add minix to OS list not supporting the -S option in pcretest.
327    40. PCRE tries to detect cases of infinite recursion at compile time, but it
328        cannot analyze patterns in sufficient detail to catch mutual recursions
329        such as ((?1))((?2)). There is now a runtime test that gives an error if a
330        subgroup is called recursively as a subpattern for a second time at the
331        same position in the subject string. In previous releases this might have
332        been caught by the recursion limit, or it might have run out of stack.
334    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
335        happen only once. PCRE was, however incorrectly giving a compile time error
336        "recursive call could loop indefinitely" because it cannot analyze the
337        pattern in sufficient detail. The compile time test no longer happens when
338        PCRE is compiling a conditional subpattern, but actual runaway loops are
339        now caught at runtime (see 40 above).
341    42. It seems that Perl allows any characters other than a closing parenthesis
342        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
343        has been changed to be the same.
345    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
346        as not to get warnings when autogen.sh is called. Also changed
347        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
349    44. To help people who use pcregrep to scan files containing exceedingly long
350        lines, the following changes have been made:
352        (a) The default value of the buffer size parameter has been increased from
353            8K to 20K. (The actual buffer used is three times this size.)
355        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
356            PCRE is built.
358        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
359            to be set at run time.
361        (d) Numerical values in pcregrep options can be followed by K or M, for
362            example --buffer-size=50K.
364        (e) If a line being scanned overflows pcregrep's buffer, an error is now
365            given and the return code is set to 2.
367    45. Add a pointer to the latest mark to the callout data block.
369    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
370        partial match of an empty string instead of no match. This was specific to
371        the use of ".".
373    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
374        complete match instead of a partial match. This bug was dependent on both
375        the PCRE_UTF8 and PCRE_DOTALL options being set.
377    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
378        starting byte set, because \b was not being ignored.
381    Version 8.12 15-Jan-2011
382    ------------------------
384    1.  Fixed some typos in the markup of the man pages, and wrote a script that
385        checks for such things as part of the documentation building process.
387    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
388        --match-limit and --recursion-limit options (added for 8.11). In
389        particular, this made one of the standard tests fail. (The integer value
390        went into the wrong half of a long int.)
392    3.  If the --colour option was given to pcregrep with -v (invert match), it
393        did strange things, either producing crazy output, or crashing. It should,
394        of course, ignore a request for colour when reporting lines that do not
395        match.
397    4.  Another pcregrep bug caused similar problems if --colour was specified with
398        -M (multiline) and the pattern match finished with a line ending.
400    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
401        matched in multiline mode, the following line was shown as part of the
402        match. This seems wrong, so I have changed it.
404    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
405        the check for further matches in the same line (so they could be coloured)
406        to overrun the end of the current line. If another match was found, it was
407        incorrectly shown (and then shown again when found in the next line).
409    7.  If pcregrep was compiled under Windows, there was a reference to the
410        function pcregrep_exit() before it was defined. I am assuming this was
411        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
412        reported by a user. I've moved the definition above the reference.
415    Version 8.11 10-Dec-2010
416    ------------------------
418    1.  (*THEN) was not working properly if there were untried alternatives prior
419        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
420        backtracked to try for "b" instead of moving to the next alternative branch
421        at the same level (in this case, to look for "c"). The Perl documentation
422        is clear that when (*THEN) is backtracked onto, it goes to the "next
423        alternative in the innermost enclosing group".
425    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
426        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
427        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
428        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
429        (*THEN).
431    3.  If \s appeared in a character class, it removed the VT character from
432        the class, even if it had been included by some previous item, for example
433        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
434        of \s, but is part of the POSIX "space" class.)
436    4.  A partial match never returns an empty string (because you can always
437        match an empty string at the end of the subject); however the checking for
438        an empty string was starting at the "start of match" point. This has been
439        changed to the "earliest inspected character" point, because the returned
440        data for a partial match starts at this character. This means that, for
441        example, /(?<=abc)def/ gives a partial match for the subject "abc"
442        (previously it gave "no match").
444    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
445        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
446        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
447        has an implication that the given string is incomplete (because a partial
448        match is preferred over a full match). For this reason, these items now
449        give a partial match in this situation. [Aside: previously, the one case
450        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
451        match rather than a full match, which was wrong by the old rules, but is
452        now correct.]
454    6.  There was a bug in the handling of #-introduced comments, recognized when
455        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
456        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
457        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
458        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
459        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
460        places in pcre_compile().
462    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
463        comments when looking ahead for named forward references to subpatterns,
464        the only newline sequence it recognized was NL. It now handles newlines
465        according to the set newline convention.
467    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
468        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
469        cater for a lack of strerror(). These oversights have been fixed.
471    9.  Added --match-limit and --recursion-limit to pcregrep.
473    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
475    11. When the -o option was used, pcregrep was setting a return code of 1, even
476        when matches were found, and --line-buffered was not being honoured.
478    12. Added an optional parentheses number to the -o and --only-matching options
479        of pcregrep.
481    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
482        can match an empty string. The code to do it in pcretest and pcredemo
483        needed fixing:
485        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
486            only one byte after an empty string match just before CRLF (this case
487            just got forgotten; "any" and "anycrlf" were OK).
489        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
490            mode when an empty string match preceded an ASCII character followed by
491            a non-ASCII character. (The code for advancing by one character rather
492            than one byte was nonsense.)
494        (c) The pcredemo.c sample program did not have any code at all to handle
495            the cases when CRLF is a valid newline sequence.
497    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
498        as a starting offset was within the subject string. There is now a new
499        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
500        negative or greater than the length of the string. In order to test this,
501        pcretest is extended to allow the setting of negative starting offsets.
503    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
504        starting offset points to the beginning of a UTF-8 character was
505        unnecessarily clumsy. I tidied it up.
507    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
508        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
510    17. Nobody had reported that the --include_dir option, which was added in
511        release 7.7 should have been called --include-dir (hyphen, not underscore)
512        for compatibility with GNU grep. I have changed it to --include-dir, but
513        left --include_dir as an undocumented synonym, and the same for
514        --exclude-dir, though that is not available in GNU grep, at least as of
515        release 2.5.4.
517    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
518        characters from a string of bytes) have been redefined so as not to use
519        loops, in order to improve performance in some environments. At the same
520        time, I abstracted some of the common code into auxiliary macros to save
521        repetition (this should not affect the compiled code).
523    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
524        compile-time error is now given if \c is not followed by an ASCII
525        character, that is, a byte less than 128. (In EBCDIC mode, the code is
526        different, and any byte value is allowed.)
528    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
529        START_OPTIMIZE option, which is now allowed at compile time - but just
530        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
531        to pcregrep and other applications that have no direct access to PCRE
532        options. The new /Y option in pcretest sets this option when calling
533        pcre_compile().
535    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
536        back references. Groups containing recursive back references were forced to
537        be atomic by that change, but in the case of named groups, the amount of
538        memory required was incorrectly computed, leading to "Failed: internal
539        error: code overflow". This has been fixed.
541    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
542        pcretest.c, to avoid build problems in some Borland environments.
545    Version 8.10 25-Jun-2010
546    ------------------------
548    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
549        THEN.
551    2.  (*ACCEPT) was not working when inside an atomic group.
553    3.  Inside a character class, \B is treated as a literal by default, but
554        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
555        causes the error). The code is unchanged, but I tidied the documentation.
557    4.  Inside a character class, PCRE always treated \R and \X as literals,
558        whereas Perl faults them if its -w option is set. I have changed PCRE so
559        that it faults them when PCRE_EXTRA is set.
561    5.  Added support for \N, which always matches any character other than
562        newline. (It is the same as "." when PCRE_DOTALL is not set.)
564    6.  When compiling pcregrep with newer versions of gcc which may have
565        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
566        declared with attribute warn_unused_result" were given. Just casting the
567        result to (void) does not stop the warnings; a more elaborate fudge is
568        needed. I've used a macro to implement this.
570    7.  Minor change to pcretest.c to avoid a compiler warning.
572    8.  Added four artifical Unicode properties to help with an option to make
573        \s etc use properties (see next item). The new properties are: Xan
574        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
576    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
577        use Unicode properties. (*UCP) at the start of a pattern can be used to set
578        this option. Modified pcretest to add /W to test this facility. Added
579        REG_UCP to make it available via the POSIX interface.
581    10. Added --line-buffered to pcregrep.
583    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
584        studied, and the match started with a letter with a code point greater than
585        127 whose first byte was different to the first byte of the other case of
586        the letter, the other case of this starting letter was not recognized
587        (#976).
589    12. If a pattern that was studied started with a repeated Unicode property
590        test, for example, \p{Nd}+, there was the theoretical possibility of
591        setting up an incorrect bitmap of starting bytes, but fortunately it could
592        not have actually happened in practice until change 8 above was made (it
593        added property types that matched character-matching opcodes).
595    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
596        possible starting bytes for non-anchored patterns.
598    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
599        \R, and also a number of cases that involve Unicode properties, both
600        explicit and implicit when PCRE_UCP is set.
602    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
603        input, it could crash or give wrong results if characters with values
604        greater than 0xc0 were present in the subject string. (Detail: it assumed
605        UTF-8 input when processing these items.)
607    16. Added a lot of (int) casts to avoid compiler warnings in systems where
608        size_t is 64-bit (#991).
610    17. Added a check for running out of memory when PCRE is compiled with
611        --disable-stack-for-recursion (#990).
613    18. If the last data line in a file for pcretest does not have a newline on
614        the end, a newline was missing in the output.
616    19. The default pcre_chartables.c file recognizes only ASCII characters (values
617        less than 128) in its various bitmaps. However, there is a facility for
618        generating tables according to the current locale when PCRE is compiled. It
619        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
620        characters, are recognized by isspace() and therefore were getting set in
621        these tables, and indeed these tables seem to approximate to ISO 8859. This
622        caused a problem in UTF-8 mode when pcre_study() was used to create a list
623        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
624        which of course cannot start UTF-8 characters. I have changed the code so
625        that only real ASCII characters (less than 128) and the correct starting
626        bytes for UTF-8 encodings are set for characters greater than 127 when in
627        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
628        altogether.)
630    20. Added the /T option to pcretest so as to be able to run tests with non-
631        standard character tables, thus making it possible to include the tests
632        used for 19 above in the standard set of tests.
634    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
635        reference to a subpattern the other side of a comment that contains an
636        opening parenthesis caused either an internal compiling error, or a
637        reference to the wrong subpattern.
640    Version 8.02 19-Mar-2010
641    ------------------------
643    1.  The Unicode data tables have been updated to Unicode 5.2.0.
645    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
646        configured.
648    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
649        original author of that file, following a query about its status.
651    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
652        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
654    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
655        quantifier applied to a forward-referencing subroutine call, could compile
656        incorrect code or give the error "internal error: previously-checked
657        referenced subpattern not found".
659    6.  Both MS Visual Studio and Symbian OS have problems with initializing
660        variables to point to external functions. For these systems, therefore,
661        pcre_malloc etc. are now initialized to local functions that call the
662        relevant global functions.
664    7.  There were two entries missing in the vectors called coptable and poptable
665        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
666        I've fixed the data, and added a kludgy way of testing at compile time that
667        the lengths are correct (equal to the number of opcodes).
669    8.  Following on from 7, I added a similar kludge to check the length of the
670        eint vector in pcreposix.c.
672    9.  Error texts for pcre_compile() are held as one long string to avoid too
673        much relocation at load time. To find a text, the string is searched,
674        counting zeros. There was no check for running off the end of the string,
675        which could happen if a new error number was added without updating the
676        string.
678    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
680    11. \K was not working if it appeared in an atomic group or in a group that
681        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
682        \K is "not well defined" if used in an assertion. PCRE now accepts it if
683        the assertion is positive, but not if it is negative.
685    12. Change 11 fortuitously reduced the size of the stack frame used in the
686        "match()" function of pcre_exec.c by one pointer. Forthcoming
687        implementation of support for (*MARK) will need an extra pointer on the
688        stack; I have reserved it now, so that the stack frame size does not
689        decrease.
691    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
692        item in branch that calls a recursion is a subroutine call - as in the
693        second branch in the above example - was incorrectly given the compile-
694        time error "recursive call could loop indefinitely" because pcre_compile()
695        was not correctly checking the subroutine for matching a non-empty string.
697    14. The checks for overrunning compiling workspace could trigger after an
698        overrun had occurred. This is a "should never occur" error, but it can be
699        triggered by pathological patterns such as hundreds of nested parentheses.
700        The checks now trigger 100 bytes before the end of the workspace.
702    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
705    Version 8.01 19-Jan-2010
706    ------------------------
708    1.  If a pattern contained a conditional subpattern with only one branch (in
709        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
710        computed the wrong minimum data length (which is of course zero for such
711        subpatterns). This could cause incorrect "no match" results.
713    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
714        the pattern is reset in the first branch, pcre_compile() failed with
715        "internal error: code overflow at offset...". This happened only when
716        the reset was to the original external option setting. (An optimization
717        abstracts leading options settings into an external setting, which was the
718        cause of this.)
720    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
721        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
722        assertion pattern did not match (meaning that the assertion was true), it
723        was incorrectly treated as false if the SKIP had been reached during the
724        matching. This also applied to assertions used as conditions.
726    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
727        assertion subpattern, including such a pattern used as a condition,
728        unpredictable results occurred, instead of the error return
731    5.  The C++ GlobalReplace function was not working like Perl for the special
732        situation when an empty string is matched. It now does the fancy magic
733        stuff that is necessary.
735    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
736        removed. (These were left over from very, very early versions of PCRE.)
738    7.  Some cosmetic changes to the code to make life easier when compiling it
739        as part of something else:
741        (a) Change DEBUG to PCRE_DEBUG.
743        (b) In pcre_compile(), rename the member of the "branch_chain" structure
744            called "current" as "current_branch", to prevent a collision with the
745            Linux macro when compiled as a kernel module.
747        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
748            prevent a collision with the Linux macro when compiled as a kernel
749            module.
751    8.  In pcre_compile() there are some checks for integer overflows that used to
752        cast potentially large values to (double). This has been changed to that
753        when building, a check for int64_t is made, and if it is found, it is used
754        instead, thus avoiding the use of floating point arithmetic. (There is no
755        other use of FP in PCRE.) If int64_t is not found, the fallback is to
756        double.
758    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
759        2005 (difference between two addresses compared to an unsigned value).
761    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
762        custom one, because of the following reported problem in Windows:
764          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
765              under Win32.
766          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
767              therefore missing the function definition.
768          - The compiler thus generates a "C" signature for the test function.
769          - The linker fails to find the "C" function.
770          - PCRE fails to configure if asked to do so against libbz2.
772    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
773        messages were output:
775          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
776          rerunning libtoolize, to keep the correct libtool macros in-tree.
777          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
779        I have done both of these things.
781    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
782        most of the time, it *can* run out if it is given a pattern that contains a
783        runaway infinite recursion. I updated the discussion in the pcrestack man
784        page.
786    13. Now that we have gone to the x.xx style of version numbers, the minor
787        version may start with zero. Using 08 or 09 is a bad idea because users
788        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
789        interpreted as invalid octal numbers. I've updated the previous comment in
790        configure.ac, and also added a check that gives an error if 08 or 09 are
791        used.
793    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
794        causing partial matching to fail when the end of the subject matched \W
795        in a UTF-8 pattern where \W was quantified with a minimum of 3.
797    15. There were some discrepancies between the declarations in pcre_internal.h
798        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
799        their definitions. The declarations used "const uschar *" and the
800        definitions used USPTR. Even though USPTR is normally defined as "const
801        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
802        reported that: "This difference in casting confuses some C++ compilers, for
803        example, SunCC recognizes above declarations as different functions and
804        generates broken code for hbpcre." I have changed the declarations to use
805        USPTR.
807    16. GNU libtool is named differently on some systems. The autogen.sh script now
808        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
809        (FreeBSD).
811    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
812        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
813        comment: "Figure out how to create a longlong from a string: strtoll and
814        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
815        instance, but it only takes 2 args instead of 3!"
817    18. A subtle bug concerned with back references has been fixed by a change of
818        specification, with a corresponding code fix. A pattern such as
819        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
820        refers, was giving matches when it shouldn't. For example, xa=xaaa would
821        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
822        same bug. Such groups have to be quantified to be useful, or contained
823        inside another quantified group. (If there's no repetition, the reference
824        can never match.) The problem arises because, having left the group and
825        moved on to the rest of the pattern, a later failure that backtracks into
826        the group uses the captured value from the final iteration of the group
827        rather than the correct earlier one. I have fixed this in PCRE by forcing
828        any group that contains a reference to itself to be an atomic group; that
829        is, there cannot be any backtracking into it once it has completed. This is
830        similar to recursive and subroutine calls.
833    Version 8.00 19-Oct-09
834    ----------------------
836    1.  The table for translating pcre_compile() error codes into POSIX error codes
837        was out-of-date, and there was no check on the pcre_compile() error code
838        being within the table. This could lead to an OK return being given in
839        error.
841    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
842        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
843        in a Windows environment.
845    3.  The pcregrep --count option prints the count for each file even when it is
846        zero, as does GNU grep. However, pcregrep was also printing all files when
847        --files-with-matches was added. Now, when both options are given, it prints
848        counts only for those files that have at least one match. (GNU grep just
849        prints the file name in this circumstance, but including the count seems
850        more useful - otherwise, why use --count?) Also ensured that the
851        combination -clh just lists non-zero counts, with no names.
853    4.  The long form of the pcregrep -F option was incorrectly implemented as
854        --fixed_strings instead of --fixed-strings. This is an incompatible change,
855        but it seems right to fix it, and I didn't think it was worth preserving
856        the old behaviour.
858    5.  The command line items --regex=pattern and --regexp=pattern were not
859        recognized by pcregrep, which required --regex pattern or --regexp pattern
860        (with a space rather than an '='). The man page documented the '=' forms,
861        which are compatible with GNU grep; these now work.
863    6.  No libpcreposix.pc file was created for pkg-config; there was just
864        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
866    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
867        when UCP support is not needed, by modifying the Python script that
868        generates it from Unicode data files. This should not matter if the module
869        is correctly used as a library, but I received one complaint about 50K of
870        unwanted data. My guess is that the person linked everything into his
871        program rather than using a library. Anyway, it does no harm.
873    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
874        was a minimum greater than 1 for a wide character in a possessive
875        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
876        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
877        character. Chaos in the form of incorrect output or a compiling loop could
878        result.
880    9.  The restrictions on what a pattern can contain when partial matching is
881        requested for pcre_exec() have been removed. All patterns can now be
882        partially matched by this function. In addition, if there are at least two
883        slots in the offset vector, the offset of the earliest inspected character
884        for the match and the offset of the end of the subject are set in them when
885        PCRE_ERROR_PARTIAL is returned.
887    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
888        synonymous with PCRE_PARTIAL, for backwards compatibility, and
889        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
890        and may be more useful for multi-segment matching.
892    11. Partial matching with pcre_exec() is now more intuitive. A partial match
893        used to be given if ever the end of the subject was reached; now it is
894        given only if matching could not proceed because another character was
895        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
896        string "Z", which now yields "no match" instead of "partial match". In the
897        case of pcre_dfa_exec(), "no match" is given if every matching path for the
898        final character ended with (*FAIL).
900    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
901        if the pattern had a "must contain" character that was already found in the
902        earlier partial match, unless partial matching was again requested. For
903        example, with the pattern /dog.(body)?/, the "must contain" character is
904        "g". If the first part-match was for the string "dog", restarting with
905        "sbody" failed. This bug has been fixed.
907    13. The string returned by pcre_dfa_exec() after a partial match has been
908        changed so that it starts at the first inspected character rather than the
909        first character of the match. This makes a difference only if the pattern
910        starts with a lookbehind assertion or \b or \B (\K is not supported by
911        pcre_dfa_exec()). It's an incompatible change, but it makes the two
912        matching functions compatible, and I think it's the right thing to do.
914    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
915        so that the demonstration program is easily available in environments where
916        PCRE has not been installed from source.
918    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
919        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
920        library.
922    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
923        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
924        is not the first non-POSIX option to be added. Clearly some people find
925        these options useful.
927    17. If a caller to the POSIX matching function regexec() passes a non-zero
928        value for nmatch with a NULL value for pmatch, the value of
929        nmatch is forced to zero.
931    18. RunGrepTest did not have a test for the availability of the -u option of
932        the diff command, as RunTest does. It now checks in the same way as
933        RunTest, and also checks for the -b option.
935    19. If an odd number of negated classes containing just a single character
936        interposed, within parentheses, between a forward reference to a named
937        subpattern and the definition of the subpattern, compilation crashed with
938        an internal error, complaining that it could not find the referenced
939        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
940        [The bug was that it was starting one character too far in when skipping
941        over the character class, thus treating the ] as data rather than
942        terminating the class. This meant it could skip too much.]
944    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
945        /g option in pcretest when the pattern contains \K, which makes it possible
946        to have an empty string match not at the start, even when the pattern is
947        anchored. Updated pcretest and pcredemo to use this option.
949    21. If the maximum number of capturing subpatterns in a recursion was greater
950        than the maximum at the outer level, the higher number was returned, but
951        with unset values at the outer level. The correct (outer level) value is
952        now given.
954    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
955        PCRE did not set those parentheses (unlike Perl). I have now found a way to
956        make it do so. The string so far is captured, making this feature
957        compatible with Perl.
959    23. The tests have been re-organized, adding tests 11 and 12, to make it
960        possible to check the Perl 5.10 features against Perl 5.10.
962    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
963        pattern matches a fixed length string. PCRE did not allow this; now it
964        does. Neither allows recursion.
966    25. I finally figured out how to implement a request to provide the minimum
967        length of subject string that was needed in order to match a given pattern.
968        (It was back references and recursion that I had previously got hung up
969        on.) This code has now been added to pcre_study(); it finds a lower bound
970        to the length of subject needed. It is not necessarily the greatest lower
971        bound, but using it to avoid searching strings that are too short does give
972        some useful speed-ups. The value is available to calling programs via
973        pcre_fullinfo().
975    26. While implementing 25, I discovered to my embarrassment that pcretest had
976        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
977        study optimizations had never been tested with that matching function.
978        Oops. What is worse, even when it was passed study data, there was a bug in
979        pcre_dfa_exec() that meant it never actually used it. Double oops. There
980        were also very few tests of studied patterns with pcre_dfa_exec().
982    27. If (?| is used to create subpatterns with duplicate numbers, they are now
983        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
984        on the other side of the coin, they are no longer allowed to have different
985        names, because these cannot be distinguished in PCRE, and this has caused
986        confusion. (This is a difference from Perl.)
988    28. When duplicate subpattern names are present (necessarily with different
989        numbers, as required by 27 above), and a test is made by name in a
990        conditional pattern, either for a subpattern having been matched, or for
991        recursion in such a pattern, all the associated numbered subpatterns are
992        tested, and the overall condition is true if the condition is true for any
993        one of them. This is the way Perl works, and is also more like the way
994        testing by number works.
997    Version 7.9 11-Apr-09
998  ---------------------  ---------------------
1000   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1001      that is more "standard", making use of automake and other autotools. There      (pcretest), all targets were linked against these libraries. This included
1002        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1003        libraries. This caused unwanted dependencies to be created. This problem
1004        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1005        pcretest is linked with readline.
1007    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1008        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1009        moved outside it again, because FALSE and TRUE are already defined in AIX,
1010        but BOOL is not.
1012    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1013        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1015    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1016        hyphens) following file names and line numbers when outputting matching
1017        lines. This is not true; no spaces are inserted. I have also clarified the
1018        wording for the --colour (or --color) option.
1020    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1021        was not coloured; this is different to GNU grep, so I have changed it to be
1022        the same.
1024    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1025        each matching line was coloured. Now it goes on to look for further matches
1026        of any of the test patterns, which is the same behaviour as GNU grep.
1028    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1029        doesn't make sense to accept an empty string match in pcregrep, so I have
1030        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1031        seems to be how GNU grep behaves.
1033    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1034        start or after a newline", because the conditional assertion was not being
1035        correctly handled. The rule now is that both the assertion and what follows
1036        in the first alternative must satisfy the test.
1038    9.  If auto-callout was enabled in a pattern with a conditional group whose
1039        condition was an assertion, PCRE could crash during matching, both with
1040        pcre_exec() and pcre_dfa_exec().
1042    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1043        used for matching.
1045    11. Unicode property support in character classes was not working for
1046        characters (bytes) greater than 127 when not in UTF-8 mode.
1048    12. Added the -M command line option to pcretest.
1050    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1052    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1054    16. Added comments and documentation about mis-use of no_arg in the C++
1055        wrapper.
1057    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1058        from Martin Jerabek that uses macro names for all relevant character and
1059        string constants.
1061    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1062        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1063        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1064        these, but not everybody uses configure.
1066    19. A conditional group that had only one branch was not being correctly
1067        recognized as an item that could match an empty string. This meant that an
1068        enclosing group might also not be so recognized, causing infinite looping
1069        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1070        with the subject "ab", where knowledge that the repeated group can match
1071        nothing is needed in order to break the loop.
1073    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1074        exec(), but without supplying a callout function, matching went wrong.
1076    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1077        leak if the size of the offset vector was greater than 30. When the vector
1078        is smaller, the saved offsets during recursion go onto a local stack
1079        vector, but for larger vectors malloc() is used. It was failing to free
1080        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1081        error, in fact).
1083    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1084        heapframe that is used only when UTF-8 support is enabled. This caused no
1085        problem, but was untidy.
1087    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1088        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1089        included within another project.
1091    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1092        slightly modified by me:
1094          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1095              not building pcregrep.
1097          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1098              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1100    25. Forward references, both numeric and by name, in patterns that made use of
1101        duplicate group numbers, could behave incorrectly or give incorrect errors,
1102        because when scanning forward to find the reference group, PCRE was not
1103        taking into account the duplicate group numbers. A pattern such as
1104        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1106    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1107        the feature of a custom pointer more persuasive (as requested by a user).
1109    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1110        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1111        pre-defined.
1113    28. Added support for (*UTF8) at the start of a pattern.
1115    29. Arrange for flags added by the "release type" setting in CMake to be shown
1116        in the configuration summary.
1119    Version 7.8 05-Sep-08
1120    ---------------------
1122    1.  Replaced UCP searching code with optimized version as implemented for Ad
1123        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1124        stage table and inline lookup instead of a function, giving speed ups of 2
1125        to 5 times on some simple patterns that I tested. Permission was given to
1126        distribute the MultiStage2.py script that generates the tables (it's not in
1127        the tarball, but is in the Subversion repository).
1129    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1130        scripts.
1132    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1133        a group with a zero qualifier. The result of the study could be incorrect,
1134        or the function might crash, depending on the pattern.
1136    4.  Caseless matching was not working for non-ASCII characters in back
1137        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1138        It now works when Unicode Property Support is available.
1140    5.  In pcretest, an escape such as \x{de} in the data was always generating
1141        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1142        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1143        truncation.
1145    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1147    7.  Added two (int) casts to pcregrep when printing the difference of two
1148        pointers, in case they are 64-bit values.
1150    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1151        test 2 if it fails.
1153    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1154        and a #define of that name to empty if it is not externally set. This is to
1155        allow users of MSVC to set it if necessary.
1157    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1158        the convenience functions in the pcre_get.c source file.
1160    11. An option change at the start of a pattern that had top-level alternatives
1161        could cause overwriting and/or a crash. This command provoked a crash in
1162        some environments:
1164          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1166        This potential security problem was recorded as CVE-2008-2371.
1168    12. For a pattern where the match had to start at the beginning or immediately
1169        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1170        pcre_dfa_exec() could read past the end of the passed subject if there was
1171        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1172        pcretest so that it places the subject at the end of its malloc-ed buffer.
1174    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1175        exec() might read past the end of the data buffer in UTF-8 mode.
1177    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1178        the data contained the byte 0x85 as part of a UTF-8 character within its
1179        first line. This applied both to normal and DFA matching.
1181    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1182        /^[^d]*?$/8 failed to match "abc".
1184    16. Added a missing copyright notice to pcrecpp_internal.h.
1186    17. Make it more clear in the documentation that values returned from
1187        pcre_exec() in ovector are byte offsets, not character counts.
1189    18. Tidied a few places to stop certain compilers from issuing warnings.
1191    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1192        supplied by Stefan Weber. I made a further small update for 7.8 because
1193        there is a change of source arrangements: the pcre_searchfuncs.c module is
1194        replaced by pcre_ucd.c.
1197    Version 7.7 07-May-08
1198    ---------------------
1200    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1201        a string to a long long, pretend we don't even have a long long." This is
1202        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1204    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1205        pre-7.6 versions, which defined a global no_arg variable instead of putting
1206        it in the RE class. (See also #8 below.)
1208    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1209        Lopes.
1211    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1213        (1) The include/exclude patterns were being applied to the whole pathnames
1214            of files, instead of just to the final components.
1216        (2) If there was more than one level of directory, the subdirectories were
1217            skipped unless they satisfied the include/exclude conditions. This is
1218            inconsistent with GNU grep (and could even be seen as contrary to the
1219            pcregrep specification - which I improved to make it absolutely clear).
1220            The action now is always to scan all levels of directory, and just
1221            apply the include/exclude patterns to regular files.
1223    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1224        --exclude_dir in the tests to avoid scanning .svn directories.
1226    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1227        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1228        doesn't support NULs in patterns.
1230    7.  Added some missing "const"s to declarations of static tables in
1231        pcre_compile.c and pcre_dfa_exec.c.
1233    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1234        caused by fix #2  above. (Subsequently also a second patch to fix the
1235        first patch. And a third patch - this was a messy problem.)
1237    9.  Applied Craig's patch to remove the use of push_back().
1239    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1240        matching function regexec().
1242    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1243        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1244        references. PCRE supports relative numbers with this syntax (I don't think
1245        Oniguruma does).
1247    12. Previously, a group with a zero repeat such as (...){0} was completely
1248        omitted from the compiled regex. However, this means that if the group
1249        was called as a subroutine from elsewhere in the pattern, things went wrong
1250        (an internal error was given). Such groups are now left in the compiled
1251        pattern, with a new opcode that causes them to be skipped at execution
1252        time.
1254    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1255        to the way PCRE behaves:
1257        (a) A lone ] character is dis-allowed (Perl treats it as data).
1259        (b) A back reference to an unmatched subpattern matches an empty string
1260            (Perl fails the current match path).
1262        (c) A data ] in a character class must be notated as \] because if the
1263            first data character in a class is ], it defines an empty class. (In
1264            Perl it is not possible to have an empty class.) The empty class []
1265            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1266            The negative empty class [^] matches any one character, independently
1267            of the DOTALL setting.
1269    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1270        non-existent subpattern following a character class starting with ']' and
1271        containing () gave an internal compiling error instead of "reference to
1272        non-existent subpattern". Fortunately, when the pattern did exist, the
1273        compiled code was correct. (When scanning forwards to check for the
1274        existencd of the subpattern, it was treating the data ']' as terminating
1275        the class, so got the count wrong. When actually compiling, the reference
1276        was subsequently set up correctly.)
1278    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1279        it was being rejected as not supported by pcre_dfa_exec(), even though
1280        other assertions are supported. I have made pcre_dfa_exec() support
1281        (*FAIL).
1283    16. The implementation of 13c above involved the invention of a new opcode,
1284        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1285        cannot be changed at match time, I realized I could make a small
1286        improvement to matching performance by compiling OP_ALLANY instead of
1287        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1288        on the OP_ANY path.
1290    17. Compiling pcretest on Windows with readline support failed without the
1291        following two fixes: (1) Make the unistd.h include conditional on
1292        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1294    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1295        ncurses library to be included for pcretest when ReadLine support is
1296        requested, but also to allow for it to be overridden. This patch came from
1297        Daniel Bergström.
1299    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1300        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1301        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1302        spotting this.
1305    Version 7.6 28-Jan-08
1306    ---------------------
1308    1.  A character class containing a very large number of characters with
1309        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1310        overflow.
1312    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1313        HAVE_LONG_LONG is not defined.
1315    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1316        bring them up to date and include new features. This patch includes:
1318        - Fixed PH's badly added libz and libbz2 support.
1319        - Fixed a problem with static linking.
1320        - Added pcredemo. [But later removed - see 7 below.]
1321        - Fixed dftables problem and added an option.
1322        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1323            HAVE_LONG_LONG.
1324        - Added readline support for pcretest.
1325        - Added an listing of the option settings after cmake has run.
1327    4.  A user submitted a patch to Makefile that makes it easy to create
1328        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1329        Makefile.am that cause it to include this special target, without
1330        affecting anything else. Note that the same mingw target plus all
1331        the other distribution libraries and programs are now supported
1332        when configuring with CMake (see 6 below) instead of with
1333        Configure/Make.
1335    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1336        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1337        exported in the Windows port". It has not yet been confirmed that the patch
1338        solves the problem, but it does no harm.
1340    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1341        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1342        with CMake, and also correct the comment about stack recursion.
1344    7.  Remove the automatic building of pcredemo from the ./configure system and
1345        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1346        of a program that users should build themselves after PCRE is installed, so
1347        building it automatically is not really right. What is more, it gave
1348        trouble in some build environments.
1350    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1353    Version 7.5 10-Jan-08
1354    ---------------------
1356    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1357        values in parens when parsing an RE using the C++ wrapper."
1359    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1360        Characters greater than 255 were excluded from the class instead of being
1361        included.
1363    3.  The same bug as (2) above applied to negated POSIX classes such as
1364        [:^space:].
1366    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1367        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1368        I have changed it.
1370    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1371        first named subpattern) and a construct such as (?&a) would reference the
1372        first named subpattern whose name started with "a" (in other words, the
1373        length check was missing). Both these problems are fixed. "Subpattern name
1374        expected" is now given for (?&) (a zero-length name), and this patch also
1375        makes it give the same error for \k'' (previously it complained that that
1376        was a reference to a non-existent subpattern).
1378    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1379        this is right because (?- can be followed by option settings as well as by
1380        digits. I have, however, made the messages clearer.
1382    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1383        than the number used in the conditional) now cause a compile-time error.
1384        This is actually not compatible with Perl, which accepts such patterns, but
1385        treats the conditional as always being FALSE (as PCRE used to), but it
1386        seems to me that giving a diagnostic is better.
1388    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1389        and messages.
1391    9.  Fix two occurrences of "backslash" in comments that should have been
1392        "backspace".
1394    10. Remove two redundant lines of code that can never be obeyed (their function
1395        was moved elsewhere).
1397    11. The program that makes PCRE's Unicode character property table had a bug
1398        which caused it to generate incorrect table entries for sequences of
1399        characters that have the same character type, but are in different scripts.
1400        It amalgamated them into a single range, with the script of the first of
1401        them. In other words, some characters were in the wrong script. There were
1402        thirteen such cases, affecting characters in the following ranges:
1404          U+002b0 - U+002c1
1405          U+0060c - U+0060d
1406          U+0061e - U+00612
1407          U+0064b - U+0065e
1408          U+0074d - U+0076d
1409          U+01800 - U+01805
1410          U+01d00 - U+01d77
1411          U+01d9b - U+01dbf
1412          U+0200b - U+0200f
1413          U+030fc - U+030fe
1414          U+03260 - U+0327f
1415          U+0fb46 - U+0fbb1
1416          U+10450 - U+1049d
1418    12. The -o option (show only the matching part of a line) for pcregrep was not
1419        compatible with GNU grep in that, if there was more than one match in a
1420        line, it showed only the first of them. It now behaves in the same way as
1421        GNU grep.
1423    13. If the -o and -v options were combined for pcregrep, it printed a blank
1424        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1425        does the same. The return code can be used to tell if there were any
1426        non-matching lines.
1428    14. Added --file-offsets and --line-offsets to pcregrep.
1430    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1431        infinitely looping recursion. The bug was that positive lookaheads were not
1432        being skipped when checking for a possible empty match (negative lookaheads
1433        and both kinds of lookbehind were skipped).
1435    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1436        inclusion of <windows.h> to before rather than after the definition of
1437        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1439    17. Specifying a possessive quantifier with a specific limit for a Unicode
1440        character property caused pcre_compile() to compile bad code, which led at
1441        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1442        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1443        caused the error; without that there was no problem.
1445    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1447    19. Added --enable-pcretest-libreadline.
1449    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1450        RE::GlobalReplace(). As a result, the number of replacements returned was
1451        double what it should be. I removed one of the increments, but Craig sent a
1452        later patch that removed the other one (the right fix) and added unit tests
1453        that check the return values (which was not done before).
1455    21. Several CMake things:
1457        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1458            the names libpcre and libpcreposix, not just pcre and pcreposix.
1460        (2) The above change means that pcretest and pcregrep are now correctly
1461            linked with the newly-built libraries, not previously installed ones.
1465    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1466        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1467        UTF-8 newline character). The key issue is that the pattern starts .*;
1468        this means that the match must be either at the beginning, or after a
1469        newline. The bug was in the code for advancing after a failed match and
1470        checking that the new position followed a newline. It was not taking
1471        account of UTF-8 characters correctly.
1473    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1474        character classes. PCRE was not treating the sequence [:...:] as a
1475        character class unless the ... were all letters. Perl, however, seems to
1476        allow any characters between [: and :], though of course it rejects as
1477        unknown any "names" that contain non-letters, because all the known class
1478        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1479        for example, whereas PCRE did not - it did not recognize a POSIX character
1480        class. This seemed a bit dangerous, so the code has been changed to be
1481        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1482        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1483        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1484        Perl does, and where it didn't before.
1486    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1487        Windows environments %n is disabled by default.
1490    Version 7.4 21-Sep-07
1491    ---------------------
1493    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1494        means that a class such as [\s] counted as "explicit reference to CR or
1495        LF". That isn't really right - the whole point of the change was to try to
1496        help when there was an actual mention of one of the two characters. So now
1497        the change happens only if \r or \n (or a literal CR or LF) character is
1498        encountered.
1500    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1501        of both had grown to the point where there were only 3 bits left.
1502        Fortunately, there was spare space in the data structure, and so I have
1503        moved the internal flags into a new 16-bit field to free up more option
1504        bits.
1506    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1507        but did not set the internal JCHANGED flag - either of these is enough to
1508        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1509        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1510        start sets both bits.
1512    4.  Added options (at build time, compile time, exec time) to change \R from
1513        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1515    5.  doc/pcresyntax.html was missing from the distribution.
1517    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1518        compatibility, even though it is no longer used.
1520    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1521        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1522        windows.h file is present (where different names are used). [This was
1523        reversed later after testing - see 16 below.]
1525    8.  Changed all #include <config.h> to #include "config.h". There were also
1526        some further <pcre.h> cases that I changed to "pcre.h".
1528    9.  When pcregrep was used with the --colour option, it missed the line ending
1529        sequence off the lines that it output.
1531    10. It was pointed out to me that arrays of string pointers cause lots of
1532        relocations when a shared library is dynamically loaded. A technique of
1533        using a single long string with a table of offsets can drastically reduce
1534        these. I have refactored PCRE in four places to do this. The result is
1535        dramatic:
1537          Originally:                          290
1538          After changing UCP table:            187
1539          After changing error message table:   43
1540          After changing table of "verbs"       36
1541          After changing table of Posix names   22
1543        Thanks to the folks working on Gregex for glib for this insight.
1545    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1546        unicode-properties was also set.
1548    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1550    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1551        checked only for CRLF.
1553    14. Added casts to pcretest.c to avoid compiler warnings.
1555    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1557    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1558        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1559        entirely. This removes changes made in 7 above.
1561    17. The CMake files have been updated, and there is now more information about
1562        building with CMake in the NON-UNIX-USE document.
1565    Version 7.3 28-Aug-07
1566    ---------------------
1568     1. In the rejigging of the build system that eventually resulted in 7.1, the
1569        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1570        brackets there is not right, since it causes compilers to look for an
1571        installed pcre.h, not the version that is in the source that is being
1572        compiled (which of course may be different). I have changed it back to:
1574          #include "pcre.h"
1576        I have a vague recollection that the change was concerned with compiling in
1577        different directories, but in the new build system, that is taken care of
1578        by the VPATH setting the Makefile.
1580     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1581        when the subject happened to end in the byte 0x85 (e.g. if the last
1582        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1583        characters but of course it shouldn't be taken as a newline when it is part
1584        of another character. The bug was that, for an unlimited repeat of . in
1585        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1586        characters when looking for a newline.
1588     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1590     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1591        in debug output.
1593     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1594        long printing in the pcrecpp unittest when running under MinGW.
1596     6. ESC_K was left out of the EBCDIC table.
1598     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1599        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1600        limit also applies to "virtual nesting" when a pattern is recursive, and in
1601        this case 1000 isn't so big. I have been able to remove this limit at the
1602        expense of backing off one optimization in certain circumstances. Normally,
1603        when pcre_exec() would call its internal match() function recursively and
1604        immediately return the result unconditionally, it uses a "tail recursion"
1605        feature to save stack. However, when a subpattern that can match an empty
1606        string has an unlimited repetition quantifier, it no longer makes this
1607        optimization. That gives it a stack frame in which to save the data for
1608        checking that an empty string has been matched. Previously this was taken
1609        from the 1000-entry workspace that had been reserved. So now there is no
1610        explicit limit, but more stack is used.
1612     8. Applied Daniel's patches to solve problems with the import/export magic
1613        syntax that is required for Windows, and which was going wrong for the
1614        pcreposix and pcrecpp parts of the library. These were overlooked when this
1615        problem was solved for the main library.
1617     9. There were some crude static tests to avoid integer overflow when computing
1618        the size of patterns that contain repeated groups with explicit upper
1619        limits. As the maximum quantifier is 65535, the maximum group length was
1620        set at 30,000 so that the product of these two numbers did not overflow a
1621        32-bit integer. However, it turns out that people want to use groups that
1622        are longer than 30,000 bytes (though not repeat them that many times).
1623        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1624        made it possible to implement the integer overflow checks in a much more
1625        dynamic way, which I have now done. The artificial limitation on group
1626        length has been removed - we now have only the limit on the total length of
1627        the compiled pattern, which depends on the LINK_SIZE setting.
1629    10. Fixed a bug in the documentation for get/copy named substring when
1630        duplicate names are permitted. If none of the named substrings are set, the
1631        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1632        empty string.
1634    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1635        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1636        because the ] is interpreted as the first data character and the
1637        terminating ] is not found. PCRE has been made compatible with Perl in this
1638        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1639        cause memory overwriting.
1641    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1642        string has been matched (to stop an infinite loop). It was not recognizing
1643        a conditional subpattern that could match an empty string if that
1644        subpattern was within another subpattern. For example, it looped when
1645        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1646        condition was not nested. This bug has been fixed.
1648    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1649        past the start of the subject in the presence of bytes with the top bit
1650        set, for example "\x8aBCD".
1652    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1653        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1655    14. Optimized (?!) to (*FAIL).
1657    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1658        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1659        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1660        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1661        does: it's just the validity check that is more restrictive.
1663    16. Inserted checks for integer overflows during escape sequence (backslash)
1664        processing, and also fixed erroneous offset values for syntax errors during
1665        backslash processing.
1667    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1668        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1670    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1671        caused an overrun.
1673    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1674        something other than just ASCII characters) inside a group that had an
1675        unlimited repeat caused a loop at compile time (while checking to see
1676        whether the group could match an empty string).
1678    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1679        [\P{Any}] did so. (Error in the code for printing property names.)
1681    21. An orphan \E inside a character class could cause a crash.
1683    22. A repeated capturing bracket such as (A)? could cause a wild memory
1684        reference during compilation.
1686    23. There are several functions in pcre_compile() that scan along a compiled
1687        expression for various reasons (e.g. to see if it's fixed length for look
1688        behind). There were bugs in these functions when a repeated \p or \P was
1689        present in the pattern. These operators have additional parameters compared
1690        with \d, etc, and these were not being taken into account when moving along
1691        the compiled data. Specifically:
1693        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1694            length.
1696        (b) An item such as \pL+ within a repeated group could cause crashes or
1697            loops.
1699        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1700            "reference to non-existent subpattern" error.
1702        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1704    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1705        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1707    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1709    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1710        character were causing crashes (broken optimization).
1712    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1713        \p or \P) caused a compile-time loop.
1715    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1716        break. For example, the unstudied pattern [\r\n]A does not match the string
1717        "\r\nA" because change 7.0/46 below moves the current point on by two
1718        characters after failing to match at the start. However, the pattern \nA
1719        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1720        the same is true. There doesn't seem any very clean way out of this, but
1721        what I have chosen to do makes the common cases work: PCRE now takes note
1722        of whether there can be an explicit match for \r or \n anywhere in the
1723        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1724        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1725        pattern has explicit CR or LF references.
1727    29. Added (*CR) etc for changing newline setting at start of pattern.
1730    Version 7.2 19-Jun-07
1731    ---------------------
1733     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1734        which is apparently normally available under Windows.
1736     2. Re-jig the pcregrep tests with different newline settings in an attempt
1737        to make them independent of the local environment's newline setting.
1739     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1741     4. Some of the "internals" tests were previously cut out when the link size
1742        was not 2, because the output contained actual offsets. The recent new
1743        "Z" feature of pcretest means that these can be cut out, making the tests
1744        usable with all link sizes.
1746     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1747        stack recursion. This gives a massive performance boost under BSD, but just
1748        a small improvement under Linux. However, it saves one field in the frame
1749        in all cases.
1751     6. Added more features from the forthcoming Perl 5.10:
1753        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1754            recursion call. It refers to the nth most recently opened parentheses.
1756        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1757            to be opened parentheses.
1759        (c) Conditions that refer to capturing parentheses can be specified
1760            relatively, for example, (?(-2)... or (?(+3)...
1762        (d) \K resets the start of the current match so that everything before
1763            is not part of it.
1765        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1767        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1768            reference syntax.
1770        (g) (?| introduces a group in which the numbering of parentheses in each
1771            alternative starts with the same number.
1773        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1775     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1778     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1779        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1780        for detecting groups that can match an empty string.
1782     9. A pattern with a very large number of alternatives (more than several
1783        hundred) was running out of internal workspace during the pre-compile
1784        phase, where pcre_compile() figures out how much memory will be needed. A
1785        bit of new cunning has reduced the workspace needed for groups with
1786        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1787        workspace instead of running out of the 4096 that are available.
1789    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1791    11. Applied patch from Google to remove an optimization that didn't quite work.
1792        The report of the bug said:
1794          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1795          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1796          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1798    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1799        it matched the wrong number of bytes.
1802    Version 7.1 24-Apr-07
1803    ---------------------
1805     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1806        that is more "standard", making use of automake and other Autotools. There
1807      is some re-arrangement of the files and adjustment of comments consequent      is some re-arrangement of the files and adjustment of comments consequent
1808      on this.      on this.
1810   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1811      for recursive directory scanning broke on some systems because the files      for recursive directory scanning broke on some systems because the files
1812      are not scanned in any specific order and on different systems the order      are not scanned in any specific order and on different systems the order
1813      was different. A call to "sort" has been inserted into RunGrepTest for the      was different. A call to "sort" has been inserted into RunGrepTest for the
1814      approprate test as a short-term fix. In the longer term there may be an      approprate test as a short-term fix. In the longer term there may be an
1815      alternative.      alternative.
1817   3. I had an email from Eric Raymond about problems translating some of PCRE's   3. I had an email from Eric Raymond about problems translating some of PCRE's
1818      man pages to HTML (despite the fact that I distribute HTML pages, some      man pages to HTML (despite the fact that I distribute HTML pages, some
1819      people do their own conversions for various reasons). The problems      people do their own conversions for various reasons). The problems
1820      concerned the use of low-level troff macros .br and .in. I have therefore      concerned the use of low-level troff macros .br and .in. I have therefore
1821      removed all such uses from the man pages (some were redundant, some could      removed all such uses from the man pages (some were redundant, some could
1822      be replaced by .nf/.fi pairs). The maintain/132html script that I use to      be replaced by .nf/.fi pairs). The 132html script that I use to generate
1823      generate HTML has been updated to handle .nf/.fi and to complain if it      HTML has been updated to handle .nf/.fi and to complain if it encounters
1824      encounters .br or .in.      .br or .in.
1826   4. Updated comments in configure.ac that get placed in config.h.in and also   4. Updated comments in configure.ac that get placed in config.h.in and also
1827      arranged for config.h to be included in the distribution, for the benefit      arranged for config.h to be included in the distribution, with the name
1828      of those who have to compile without Autotools (compare pcre.h).      config.h.generic, for the benefit of those who have to compile without
1829        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1830   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan  
1831      Weber: (1) pcre_internal.h was missing some function renames; (2) updated   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1832      makevp.bat for the current PCRE, using the additional files !compile.txt,      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1833      !linklib.txt, and pcregexp.pas.      makevp.bat for the current PCRE, using the additional files
1834        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1835   6. A Windows user reported a minor discrepancy with test 2, which turned out  
1836      to be caused by a trailing space on an input line that had got lost in his   6. A Windows user reported a minor discrepancy with test 2, which turned out
1837        to be caused by a trailing space on an input line that had got lost in his
1838      copy. The trailing space was an accident, so I've just removed it.      copy. The trailing space was an accident, so I've just removed it.
1840     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1841        that is needed.
1843     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1844        as "const" (a) because they are and (b) because it helps the PHP
1845        maintainers who have recently made a script to detect big data structures
1846        in the php code that should be moved to the .rodata section. I remembered
1847        to update Builducptable as well, so it won't revert if ucptable.h is ever
1848        re-created.
1850     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1851        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1852        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1853        support is not required. This saves 1.5-2K of code, which is important in
1854        some applications.
1856        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1857        so as not to refer to the tables, even though these functions will never be
1858        called when UTF-8 support is disabled. Otherwise there are problems with a
1859        shared library.
1861    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1863        (a) It was defining its arguments as char * instead of void *.
1865        (b) It was assuming that all moves were upwards in memory; this was true
1866            a long time ago when I wrote it, but is no longer the case.
1868        The emulated memove() is provided for those environments that have neither
1869        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1870        is clearly not the case, as these two bugs were recently reported.
1872    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1873        and Detrail to create the HTML documentation, the .txt form of the man
1874        pages, and it removes trailing spaces from listed files. It also creates
1875        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1876        case, it wraps all the #defines with #ifndefs. This script should be run
1877        before "make dist".
1879    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1880        with Unicode property support.
1882        (a) For a maximizing quantifier, if the two different cases of the
1883            character were of different lengths in their UTF-8 codings (there are
1884            some cases like this - I found 11), and the matching function had to
1885            back up over a mixture of the two cases, it incorrectly assumed they
1886            were both the same length.
1888        (b) When PCRE was configured to use the heap rather than the stack for
1889            recursion during matching, it was not correctly preserving the data for
1890            the other case of a UTF-8 character when checking ahead for a match
1891            while processing a minimizing repeat. If the check also involved
1892            matching a wide character, but failed, corruption could cause an
1893            erroneous result when trying to check for a repeat of the original
1894            character.
1896    13. Some tidying changes to the testing mechanism:
1898        (a) The RunTest script now detects the internal link size and whether there
1899            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1900            values substituted by "configure". (The RunGrepTest script already did
1901            this for UTF-8.) The configure.ac script no longer substitutes the
1902            relevant variables.
1904        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1905            with length and offset values. This means that the output is different
1906            for different internal link sizes. Test 2 is skipped for link sizes
1907            other than 2 because of this, bypassing the problem. Unfortunately,
1908            there was also a test in test 3 (the locale tests) that used /B and
1909            failed for link sizes other than 2. Rather than cut the whole test out,
1910            I have added a new /Z option to pcretest that replaces the length and
1911            offset values with spaces. This is now used to make test 3 independent
1912            of link size. (Test 2 will be tidied up later.)
1914    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1915        segmentation fault instead of returning the appropriate error message.
1917    15. In multiline mode when the newline sequence was set to "any", the pattern
1918        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1919        This doesn't seem right; it now treats the CRLF combination as the line
1920        ending, and so does not match in that case. It's only a pattern such as ^$
1921        that would hit this one: something like ^ABC$ would have failed after \r
1922        and then tried again after \r\n.
1924    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1925        in an attempt to make files that differ only in their line terminators
1926        compare equal. This works on Linux.
1928    17. Under certain error circumstances pcregrep might try to free random memory
1929        as it exited. This is now fixed, thanks to valgrind.
1931    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1932        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1933        was because its rules for how to advance for /g after matching an empty
1934        string at the end of a line did not allow for this case. They now check for
1935        it specially.
1937    20. pcretest is supposed to handle patterns and data of any length, by
1938        extending its buffers when necessary. It was getting this wrong when the
1939        buffer for a data line had to be extended.
1941    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1942        CRLF as a newline sequence.
1944    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1945        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1946        I have nevertheless tidied it up.
1948    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1950    24. Added a man page for pcre-config.
1953  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
1954  ---------------------  ---------------------

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