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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.20
5    ------------
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8       a POSIX class. After further experiments with Perl, which convinced me that
9       Perl has bugs and confusions, a closing square bracket is no longer allowed
10       in a POSIX name.
12    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
13       substring, but while checking the failing first alternative, substring 1 is
14       temporarily captured. If the output vector supplied to pcre_exec() was not
15       big enough for this capture, the yield of the function was still zero
16       ("insufficient space for captured substrings"). This cannot be totally fixed
17       without adding another stack variable, which seems a lot of expense for a
18       edge case. However, I have improved the situation in cases such as
19       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
20       fewer than the maximum number of slots in the ovector have been set.
22    3. Related to (2) above: when there are more back references in a pattern than
23       slots in the output vector, pcre_exec() uses temporary memory during
24       matching, and copies in the captures as far as possible afterwards. It was
25       using the entire output vector, but this conflicts with the specification
26       that only 2/3 is used for passing back captured substrings. Now it uses only
27       the first 2/3, for compatibility. This is, of course, another edge case.
29    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
30       main code base, and can be used by building with --enable-jit. When this is
31       done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
32       runtime --no-jit option is given.
34    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
35       ovector, the return from the function was zero, implying that there were
36       other matches that did not fit. The correct "exactly full" value is now
37       returned.
39    6. If a subpattern that was called recursively or as a subroutine contained
40       (*PRUNE) or any other control that caused it to give a non-standard return,
41       invalid errors such as "Error -26 (nested recursion at the same subject
42       position)" or even infinite loops could occur.
45    Version 8.13 16-Aug-2011
46    ------------------------
48    1.  The Unicode data tables have been updated to Unicode 6.0.0.
50    2.  Two minor typos in pcre_internal.h have been fixed.
52    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
53        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
54        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
56    4.  There were a number of related bugs in the code for matching backrefences
57        caselessly in UTF-8 mode when codes for the characters concerned were
58        different numbers of bytes. For example, U+023A and U+2C65 are an upper
59        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
60        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
61        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
62        2-byte code at the end of the subject (it thought there wasn't enough data
63        left).
65    5.  Comprehensive information about what went wrong is now returned by
66        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
67        as the output vector has at least 2 elements. The offset of the start of
68        the failing character and a reason code are placed in the vector.
70    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
71        now returned is for the first byte of the failing character, instead of the
72        last byte inspected. This is an incompatible change, but I hope it is small
73        enough not to be a problem. It makes the returned offset consistent with
74        pcre_exec() and pcre_dfa_exec().
76    7.  pcretest now gives a text phrase as well as the error number when
77        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
78        failure, the offset and reason code are output.
80    8.  When \R was used with a maximizing quantifier it failed to skip backwards
81        over a \r\n pair if the subsequent match failed. Instead, it just skipped
82        back over a single character (\n). This seems wrong (because it treated the
83        two characters as a single entity when going forwards), conflicts with the
84        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
85        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
86        has been changed.
88    9.  Some internal refactoring has changed the processing so that the handling
89        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
90        time (the PCRE_DOTALL option was changed this way some time ago: version
91        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
92        which was always a bit of a fudge. It also means that there is one less
93        argument for the match() function, which reduces its stack requirements
94        slightly. This change also fixes an incompatibility with Perl: the pattern
95        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
97    10. More internal refactoring has drastically reduced the number of recursive
98        calls to match() for possessively repeated groups such as (abc)++ when
99        using pcre_exec().
101    11. While implementing 10, a number of bugs in the handling of groups were
102        discovered and fixed:
104        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
105        (a|)*(?1) gave a compile-time internal error.
106        ((a|)+)+  did not notice that the outer group could match an empty string.
107        (^a|^)+   was not marked as anchored.
108        (.*a|.*)+ was not marked as matching at start or after a newline.
110    12. Yet more internal refactoring has removed another argument from the match()
111        function. Special calls to this function are now indicated by setting a
112        value in a variable in the "match data" data block.
114    13. Be more explicit in pcre_study() instead of relying on "default" for
115        opcodes that mean there is no starting character; this means that when new
116        ones are added and accidentally left out of pcre_study(), testing should
117        pick them up.
119    14. The -s option of pcretest has been documented for ages as being an old
120        synonym of -m (show memory usage). I have changed it to mean "force study
121        for every regex", that is, assume /S for every regex. This is similar to -i
122        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
123        using it. It makes it easier to run collections of tests with and without
124        study enabled, and thereby test pcre_study() more easily. All the standard
125        tests are now run with and without -s (but some patterns can be marked as
126        "never study" - see 20 below).
128    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
129        restoration of the capturing data to the outer values was not happening
130        correctly.
132    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
133        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
134        pattern had matched an empty string, and so incorrectly returned a no
135        match.
137    17. There was optimizing code for the last branch of non-capturing parentheses,
138        and also for the obeyed branch of a conditional subexpression, which used
139        tail recursion to cut down on stack usage. Unfortunately, now that there is
140        the possibility of (*THEN) occurring in these branches, tail recursion is
141        no longer possible because the return has to be checked for (*THEN). These
142        two optimizations have therefore been removed.
144    18. If a pattern containing \R was studied, it was assumed that \R always
145        matched two bytes, thus causing the minimum subject length to be
146        incorrectly computed because \R can also match just one byte.
148    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
149        was incorrectly computed.
151    20. If /S is present twice on a test pattern in pcretest input, it now
152        *disables* studying, thereby overriding the use of -s on the command line
153        (see 14 above). This is necessary for one or two tests to keep the output
154        identical in both cases.
156    21. When (*ACCEPT) was used in an assertion that matched an empty string and
157        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
159    22. When an atomic group that contained a capturing parenthesis was
160        successfully matched, but the branch in which it appeared failed, the
161        capturing was not being forgotten if a higher numbered group was later
162        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
163        group 1 to "a", when in fact it should be unset. This applied to multi-
164        branched capturing and non-capturing groups, repeated or not, and also to
165        positive assertions (capturing in negative assertions does not happen
166        in PCRE) and also to nested atomic groups.
168    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
169        subject after a captured substring, to make it easier to tell which of a
170        number of identical substrings has been captured.
172    24. The way atomic groups are processed by pcre_exec() has been changed so that
173        if they are repeated, backtracking one repetition now resets captured
174        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
175        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
176        "aaa". Previously, it would have been "a". As part of this code
177        refactoring, the way recursive calls are handled has also been changed.
179    25. If an assertion condition captured any substrings, they were not passed
180        back unless some other capturing happened later. For example, if
181        (?(?=(a))a) was matched against "a", no capturing was returned.
183    26. When studying a pattern that contained subroutine calls or assertions,
184        the code for finding the minimum length of a possible match was handling
185        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
186        group 1 called group 2 while simultaneously a separate group 2 called group
187        1). A stack overflow occurred in this case. I have fixed this by limiting
188        the recursion depth to 10.
190    27. Updated RunTest.bat in the distribution to the version supplied by Tom
191        Fortmann. This supports explicit test numbers on the command line, and has
192        argument validation and error reporting.
194    28. An instance of \X with an unlimited repeat could fail if at any point the
195        first character it looked at was a mark character.
197    29. Some minor code refactoring concerning Unicode properties and scripts
198        should reduce the stack requirement of match() slightly.
200    30. Added the '=' option to pcretest to check the setting of unused capturing
201        slots at the end of the pattern, which are documented as being -1, but are
202        not included in the return count.
204    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
205        compiled something random. Now it gives a compile-time error (as does
206        Perl).
208    32. A *MARK encountered during the processing of a positive assertion is now
209        recorded and passed back (compatible with Perl).
211    33. If --only-matching or --colour was set on a pcregrep call whose pattern
212        had alternative anchored branches, the search for a second match in a line
213        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
214        matched the line "0102" twice. The same bug affected patterns that started
215        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
216        twice.
218    34. Previously, PCRE did not allow quantification of assertions. However, Perl
219        does, and because of capturing effects, quantifying parenthesized
220        assertions may at times be useful. Quantifiers are now allowed for
221        parenthesized assertions.
223    35. A minor code tidy in pcre_compile() when checking options for \R usage.
225    36. \g was being checked for fancy things in a character class, when it should
226        just be a literal "g".
228    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
229        appearance of a nested POSIX class supersedes an apparent external class.
230        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
231        unescaped square brackets may also appear as part of class names. For
232        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
233        more like Perl. (But see 8.20/1 above.)
235    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
236        was because it thought it was \N{name}, which is not supported).
238    39. Add minix to OS list not supporting the -S option in pcretest.
240    40. PCRE tries to detect cases of infinite recursion at compile time, but it
241        cannot analyze patterns in sufficient detail to catch mutual recursions
242        such as ((?1))((?2)). There is now a runtime test that gives an error if a
243        subgroup is called recursively as a subpattern for a second time at the
244        same position in the subject string. In previous releases this might have
245        been caught by the recursion limit, or it might have run out of stack.
247    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
248        happen only once. PCRE was, however incorrectly giving a compile time error
249        "recursive call could loop indefinitely" because it cannot analyze the
250        pattern in sufficient detail. The compile time test no longer happens when
251        PCRE is compiling a conditional subpattern, but actual runaway loops are
252        now caught at runtime (see 40 above).
254    42. It seems that Perl allows any characters other than a closing parenthesis
255        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
256        has been changed to be the same.
258    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
259        as not to get warnings when autogen.sh is called. Also changed
260        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
262    44. To help people who use pcregrep to scan files containing exceedingly long
263        lines, the following changes have been made:
265        (a) The default value of the buffer size parameter has been increased from
266            8K to 20K. (The actual buffer used is three times this size.)
268        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
269            PCRE is built.
271        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
272            to be set at run time.
274        (d) Numerical values in pcregrep options can be followed by K or M, for
275            example --buffer-size=50K.
277        (e) If a line being scanned overflows pcregrep's buffer, an error is now
278            given and the return code is set to 2.
280    45. Add a pointer to the latest mark to the callout data block.
282    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
283        partial match of an empty string instead of no match. This was specific to
284        the use of ".".
286    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
287        complete match instead of a partial match. This bug was dependent on both
288        the PCRE_UTF8 and PCRE_DOTALL options being set.
290    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
291        starting byte set, because \b was not being ignored.
294    Version 8.12 15-Jan-2011
295    ------------------------
297    1.  Fixed some typos in the markup of the man pages, and wrote a script that
298        checks for such things as part of the documentation building process.
300    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
301        --match-limit and --recursion-limit options (added for 8.11). In
302        particular, this made one of the standard tests fail. (The integer value
303        went into the wrong half of a long int.)
305    3.  If the --colour option was given to pcregrep with -v (invert match), it
306        did strange things, either producing crazy output, or crashing. It should,
307        of course, ignore a request for colour when reporting lines that do not
308        match.
310    4.  Another pcregrep bug caused similar problems if --colour was specified with
311        -M (multiline) and the pattern match finished with a line ending.
313    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
314        matched in multiline mode, the following line was shown as part of the
315        match. This seems wrong, so I have changed it.
317    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
318        the check for further matches in the same line (so they could be coloured)
319        to overrun the end of the current line. If another match was found, it was
320        incorrectly shown (and then shown again when found in the next line).
322    7.  If pcregrep was compiled under Windows, there was a reference to the
323        function pcregrep_exit() before it was defined. I am assuming this was
324        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
325        reported by a user. I've moved the definition above the reference.
328    Version 8.11 10-Dec-2010
329    ------------------------
331    1.  (*THEN) was not working properly if there were untried alternatives prior
332        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
333        backtracked to try for "b" instead of moving to the next alternative branch
334        at the same level (in this case, to look for "c"). The Perl documentation
335        is clear that when (*THEN) is backtracked onto, it goes to the "next
336        alternative in the innermost enclosing group".
338    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
339        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
340        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
341        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
342        (*THEN).
344    3.  If \s appeared in a character class, it removed the VT character from
345        the class, even if it had been included by some previous item, for example
346        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
347        of \s, but is part of the POSIX "space" class.)
349    4.  A partial match never returns an empty string (because you can always
350        match an empty string at the end of the subject); however the checking for
351        an empty string was starting at the "start of match" point. This has been
352        changed to the "earliest inspected character" point, because the returned
353        data for a partial match starts at this character. This means that, for
354        example, /(?<=abc)def/ gives a partial match for the subject "abc"
355        (previously it gave "no match").
357    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
358        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
359        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
360        has an implication that the given string is incomplete (because a partial
361        match is preferred over a full match). For this reason, these items now
362        give a partial match in this situation. [Aside: previously, the one case
363        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
364        match rather than a full match, which was wrong by the old rules, but is
365        now correct.]
367    6.  There was a bug in the handling of #-introduced comments, recognized when
368        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
369        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
370        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
371        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
372        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
373        places in pcre_compile().
375    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
376        comments when looking ahead for named forward references to subpatterns,
377        the only newline sequence it recognized was NL. It now handles newlines
378        according to the set newline convention.
380    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
381        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
382        cater for a lack of strerror(). These oversights have been fixed.
384    9.  Added --match-limit and --recursion-limit to pcregrep.
386    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
388    11. When the -o option was used, pcregrep was setting a return code of 1, even
389        when matches were found, and --line-buffered was not being honoured.
391    12. Added an optional parentheses number to the -o and --only-matching options
392        of pcregrep.
394    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
395        can match an empty string. The code to do it in pcretest and pcredemo
396        needed fixing:
398        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
399            only one byte after an empty string match just before CRLF (this case
400            just got forgotten; "any" and "anycrlf" were OK).
402        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
403            mode when an empty string match preceded an ASCII character followed by
404            a non-ASCII character. (The code for advancing by one character rather
405            than one byte was nonsense.)
407        (c) The pcredemo.c sample program did not have any code at all to handle
408            the cases when CRLF is a valid newline sequence.
410    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
411        as a starting offset was within the subject string. There is now a new
412        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
413        negative or greater than the length of the string. In order to test this,
414        pcretest is extended to allow the setting of negative starting offsets.
416    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
417        starting offset points to the beginning of a UTF-8 character was
418        unnecessarily clumsy. I tidied it up.
420    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
421        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
423    17. Nobody had reported that the --include_dir option, which was added in
424        release 7.7 should have been called --include-dir (hyphen, not underscore)
425        for compatibility with GNU grep. I have changed it to --include-dir, but
426        left --include_dir as an undocumented synonym, and the same for
427        --exclude-dir, though that is not available in GNU grep, at least as of
428        release 2.5.4.
430    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
431        characters from a string of bytes) have been redefined so as not to use
432        loops, in order to improve performance in some environments. At the same
433        time, I abstracted some of the common code into auxiliary macros to save
434        repetition (this should not affect the compiled code).
436    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
437        compile-time error is now given if \c is not followed by an ASCII
438        character, that is, a byte less than 128. (In EBCDIC mode, the code is
439        different, and any byte value is allowed.)
441    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
442        START_OPTIMIZE option, which is now allowed at compile time - but just
443        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
444        to pcregrep and other applications that have no direct access to PCRE
445        options. The new /Y option in pcretest sets this option when calling
446        pcre_compile().
448    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
449        back references. Groups containing recursive back references were forced to
450        be atomic by that change, but in the case of named groups, the amount of
451        memory required was incorrectly computed, leading to "Failed: internal
452        error: code overflow". This has been fixed.
454    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
455        pcretest.c, to avoid build problems in some Borland environments.
458    Version 8.10 25-Jun-2010
459    ------------------------
461    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
462        THEN.
464    2.  (*ACCEPT) was not working when inside an atomic group.
466    3.  Inside a character class, \B is treated as a literal by default, but
467        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
468        causes the error). The code is unchanged, but I tidied the documentation.
470    4.  Inside a character class, PCRE always treated \R and \X as literals,
471        whereas Perl faults them if its -w option is set. I have changed PCRE so
472        that it faults them when PCRE_EXTRA is set.
474    5.  Added support for \N, which always matches any character other than
475        newline. (It is the same as "." when PCRE_DOTALL is not set.)
477    6.  When compiling pcregrep with newer versions of gcc which may have
478        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
479        declared with attribute warn_unused_result" were given. Just casting the
480        result to (void) does not stop the warnings; a more elaborate fudge is
481        needed. I've used a macro to implement this.
483    7.  Minor change to pcretest.c to avoid a compiler warning.
485    8.  Added four artifical Unicode properties to help with an option to make
486        \s etc use properties (see next item). The new properties are: Xan
487        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
489    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
490        use Unicode properties. (*UCP) at the start of a pattern can be used to set
491        this option. Modified pcretest to add /W to test this facility. Added
492        REG_UCP to make it available via the POSIX interface.
494    10. Added --line-buffered to pcregrep.
496    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
497        studied, and the match started with a letter with a code point greater than
498        127 whose first byte was different to the first byte of the other case of
499        the letter, the other case of this starting letter was not recognized
500        (#976).
502    12. If a pattern that was studied started with a repeated Unicode property
503        test, for example, \p{Nd}+, there was the theoretical possibility of
504        setting up an incorrect bitmap of starting bytes, but fortunately it could
505        not have actually happened in practice until change 8 above was made (it
506        added property types that matched character-matching opcodes).
508    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
509        possible starting bytes for non-anchored patterns.
511    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
512        \R, and also a number of cases that involve Unicode properties, both
513        explicit and implicit when PCRE_UCP is set.
515    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
516        input, it could crash or give wrong results if characters with values
517        greater than 0xc0 were present in the subject string. (Detail: it assumed
518        UTF-8 input when processing these items.)
520    16. Added a lot of (int) casts to avoid compiler warnings in systems where
521        size_t is 64-bit (#991).
523    17. Added a check for running out of memory when PCRE is compiled with
524        --disable-stack-for-recursion (#990).
526    18. If the last data line in a file for pcretest does not have a newline on
527        the end, a newline was missing in the output.
529    19. The default pcre_chartables.c file recognizes only ASCII characters (values
530        less than 128) in its various bitmaps. However, there is a facility for
531        generating tables according to the current locale when PCRE is compiled. It
532        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
533        characters, are recognized by isspace() and therefore were getting set in
534        these tables, and indeed these tables seem to approximate to ISO 8859. This
535        caused a problem in UTF-8 mode when pcre_study() was used to create a list
536        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
537        which of course cannot start UTF-8 characters. I have changed the code so
538        that only real ASCII characters (less than 128) and the correct starting
539        bytes for UTF-8 encodings are set for characters greater than 127 when in
540        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
541        altogether.)
543    20. Added the /T option to pcretest so as to be able to run tests with non-
544        standard character tables, thus making it possible to include the tests
545        used for 19 above in the standard set of tests.
547    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
548        reference to a subpattern the other side of a comment that contains an
549        opening parenthesis caused either an internal compiling error, or a
550        reference to the wrong subpattern.
553    Version 8.02 19-Mar-2010
554    ------------------------
556    1.  The Unicode data tables have been updated to Unicode 5.2.0.
558    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
559        configured.
561    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
562        original author of that file, following a query about its status.
564    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
565        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
567    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
568        quantifier applied to a forward-referencing subroutine call, could compile
569        incorrect code or give the error "internal error: previously-checked
570        referenced subpattern not found".
572    6.  Both MS Visual Studio and Symbian OS have problems with initializing
573        variables to point to external functions. For these systems, therefore,
574        pcre_malloc etc. are now initialized to local functions that call the
575        relevant global functions.
577    7.  There were two entries missing in the vectors called coptable and poptable
578        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
579        I've fixed the data, and added a kludgy way of testing at compile time that
580        the lengths are correct (equal to the number of opcodes).
582    8.  Following on from 7, I added a similar kludge to check the length of the
583        eint vector in pcreposix.c.
585    9.  Error texts for pcre_compile() are held as one long string to avoid too
586        much relocation at load time. To find a text, the string is searched,
587        counting zeros. There was no check for running off the end of the string,
588        which could happen if a new error number was added without updating the
589        string.
591    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
593    11. \K was not working if it appeared in an atomic group or in a group that
594        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
595        \K is "not well defined" if used in an assertion. PCRE now accepts it if
596        the assertion is positive, but not if it is negative.
598    12. Change 11 fortuitously reduced the size of the stack frame used in the
599        "match()" function of pcre_exec.c by one pointer. Forthcoming
600        implementation of support for (*MARK) will need an extra pointer on the
601        stack; I have reserved it now, so that the stack frame size does not
602        decrease.
604    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
605        item in branch that calls a recursion is a subroutine call - as in the
606        second branch in the above example - was incorrectly given the compile-
607        time error "recursive call could loop indefinitely" because pcre_compile()
608        was not correctly checking the subroutine for matching a non-empty string.
610    14. The checks for overrunning compiling workspace could trigger after an
611        overrun had occurred. This is a "should never occur" error, but it can be
612        triggered by pathological patterns such as hundreds of nested parentheses.
613        The checks now trigger 100 bytes before the end of the workspace.
615    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
618    Version 8.01 19-Jan-2010
619    ------------------------
621    1.  If a pattern contained a conditional subpattern with only one branch (in
622        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
623        computed the wrong minimum data length (which is of course zero for such
624        subpatterns). This could cause incorrect "no match" results.
626    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
627        the pattern is reset in the first branch, pcre_compile() failed with
628        "internal error: code overflow at offset...". This happened only when
629        the reset was to the original external option setting. (An optimization
630        abstracts leading options settings into an external setting, which was the
631        cause of this.)
633    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
634        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
635        assertion pattern did not match (meaning that the assertion was true), it
636        was incorrectly treated as false if the SKIP had been reached during the
637        matching. This also applied to assertions used as conditions.
639    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
640        assertion subpattern, including such a pattern used as a condition,
641        unpredictable results occurred, instead of the error return
644    5.  The C++ GlobalReplace function was not working like Perl for the special
645        situation when an empty string is matched. It now does the fancy magic
646        stuff that is necessary.
648    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
649        removed. (These were left over from very, very early versions of PCRE.)
651    7.  Some cosmetic changes to the code to make life easier when compiling it
652        as part of something else:
654        (a) Change DEBUG to PCRE_DEBUG.
656        (b) In pcre_compile(), rename the member of the "branch_chain" structure
657            called "current" as "current_branch", to prevent a collision with the
658            Linux macro when compiled as a kernel module.
660        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
661            prevent a collision with the Linux macro when compiled as a kernel
662            module.
664    8.  In pcre_compile() there are some checks for integer overflows that used to
665        cast potentially large values to (double). This has been changed to that
666        when building, a check for int64_t is made, and if it is found, it is used
667        instead, thus avoiding the use of floating point arithmetic. (There is no
668        other use of FP in PCRE.) If int64_t is not found, the fallback is to
669        double.
671    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
672        2005 (difference between two addresses compared to an unsigned value).
674    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
675        custom one, because of the following reported problem in Windows:
677          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
678              under Win32.
679          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
680              therefore missing the function definition.
681          - The compiler thus generates a "C" signature for the test function.
682          - The linker fails to find the "C" function.
683          - PCRE fails to configure if asked to do so against libbz2.
685    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
686        messages were output:
688          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
689          rerunning libtoolize, to keep the correct libtool macros in-tree.
690          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
692        I have done both of these things.
694    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
695        most of the time, it *can* run out if it is given a pattern that contains a
696        runaway infinite recursion. I updated the discussion in the pcrestack man
697        page.
699    13. Now that we have gone to the x.xx style of version numbers, the minor
700        version may start with zero. Using 08 or 09 is a bad idea because users
701        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
702        interpreted as invalid octal numbers. I've updated the previous comment in
703        configure.ac, and also added a check that gives an error if 08 or 09 are
704        used.
706    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
707        causing partial matching to fail when the end of the subject matched \W
708        in a UTF-8 pattern where \W was quantified with a minimum of 3.
710    15. There were some discrepancies between the declarations in pcre_internal.h
711        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
712        their definitions. The declarations used "const uschar *" and the
713        definitions used USPTR. Even though USPTR is normally defined as "const
714        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
715        reported that: "This difference in casting confuses some C++ compilers, for
716        example, SunCC recognizes above declarations as different functions and
717        generates broken code for hbpcre." I have changed the declarations to use
718        USPTR.
720    16. GNU libtool is named differently on some systems. The autogen.sh script now
721        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
722        (FreeBSD).
724    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
725        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
726        comment: "Figure out how to create a longlong from a string: strtoll and
727        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
728        instance, but it only takes 2 args instead of 3!"
730    18. A subtle bug concerned with back references has been fixed by a change of
731        specification, with a corresponding code fix. A pattern such as
732        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
733        refers, was giving matches when it shouldn't. For example, xa=xaaa would
734        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
735        same bug. Such groups have to be quantified to be useful, or contained
736        inside another quantified group. (If there's no repetition, the reference
737        can never match.) The problem arises because, having left the group and
738        moved on to the rest of the pattern, a later failure that backtracks into
739        the group uses the captured value from the final iteration of the group
740        rather than the correct earlier one. I have fixed this in PCRE by forcing
741        any group that contains a reference to itself to be an atomic group; that
742        is, there cannot be any backtracking into it once it has completed. This is
743        similar to recursive and subroutine calls.
746    Version 8.00 19-Oct-09
747    ----------------------
749    1.  The table for translating pcre_compile() error codes into POSIX error codes
750        was out-of-date, and there was no check on the pcre_compile() error code
751        being within the table. This could lead to an OK return being given in
752        error.
754    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
755        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
756        in a Windows environment.
758    3.  The pcregrep --count option prints the count for each file even when it is
759        zero, as does GNU grep. However, pcregrep was also printing all files when
760        --files-with-matches was added. Now, when both options are given, it prints
761        counts only for those files that have at least one match. (GNU grep just
762        prints the file name in this circumstance, but including the count seems
763        more useful - otherwise, why use --count?) Also ensured that the
764        combination -clh just lists non-zero counts, with no names.
766    4.  The long form of the pcregrep -F option was incorrectly implemented as
767        --fixed_strings instead of --fixed-strings. This is an incompatible change,
768        but it seems right to fix it, and I didn't think it was worth preserving
769        the old behaviour.
771    5.  The command line items --regex=pattern and --regexp=pattern were not
772        recognized by pcregrep, which required --regex pattern or --regexp pattern
773        (with a space rather than an '='). The man page documented the '=' forms,
774        which are compatible with GNU grep; these now work.
776    6.  No libpcreposix.pc file was created for pkg-config; there was just
777        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
779    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
780        when UCP support is not needed, by modifying the Python script that
781        generates it from Unicode data files. This should not matter if the module
782        is correctly used as a library, but I received one complaint about 50K of
783        unwanted data. My guess is that the person linked everything into his
784        program rather than using a library. Anyway, it does no harm.
786    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
787        was a minimum greater than 1 for a wide character in a possessive
788        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
789        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
790        character. Chaos in the form of incorrect output or a compiling loop could
791        result.
793    9.  The restrictions on what a pattern can contain when partial matching is
794        requested for pcre_exec() have been removed. All patterns can now be
795        partially matched by this function. In addition, if there are at least two
796        slots in the offset vector, the offset of the earliest inspected character
797        for the match and the offset of the end of the subject are set in them when
798        PCRE_ERROR_PARTIAL is returned.
800    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
801        synonymous with PCRE_PARTIAL, for backwards compatibility, and
802        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
803        and may be more useful for multi-segment matching.
805    11. Partial matching with pcre_exec() is now more intuitive. A partial match
806        used to be given if ever the end of the subject was reached; now it is
807        given only if matching could not proceed because another character was
808        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
809        string "Z", which now yields "no match" instead of "partial match". In the
810        case of pcre_dfa_exec(), "no match" is given if every matching path for the
811        final character ended with (*FAIL).
813    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
814        if the pattern had a "must contain" character that was already found in the
815        earlier partial match, unless partial matching was again requested. For
816        example, with the pattern /dog.(body)?/, the "must contain" character is
817        "g". If the first part-match was for the string "dog", restarting with
818        "sbody" failed. This bug has been fixed.
820    13. The string returned by pcre_dfa_exec() after a partial match has been
821        changed so that it starts at the first inspected character rather than the
822        first character of the match. This makes a difference only if the pattern
823        starts with a lookbehind assertion or \b or \B (\K is not supported by
824        pcre_dfa_exec()). It's an incompatible change, but it makes the two
825        matching functions compatible, and I think it's the right thing to do.
827    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
828        so that the demonstration program is easily available in environments where
829        PCRE has not been installed from source.
831    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
832        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
833        library.
835    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
836        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
837        is not the first non-POSIX option to be added. Clearly some people find
838        these options useful.
840    17. If a caller to the POSIX matching function regexec() passes a non-zero
841        value for nmatch with a NULL value for pmatch, the value of
842        nmatch is forced to zero.
844    18. RunGrepTest did not have a test for the availability of the -u option of
845        the diff command, as RunTest does. It now checks in the same way as
846        RunTest, and also checks for the -b option.
848    19. If an odd number of negated classes containing just a single character
849        interposed, within parentheses, between a forward reference to a named
850        subpattern and the definition of the subpattern, compilation crashed with
851        an internal error, complaining that it could not find the referenced
852        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
853        [The bug was that it was starting one character too far in when skipping
854        over the character class, thus treating the ] as data rather than
855        terminating the class. This meant it could skip too much.]
857    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
858        /g option in pcretest when the pattern contains \K, which makes it possible
859        to have an empty string match not at the start, even when the pattern is
860        anchored. Updated pcretest and pcredemo to use this option.
862    21. If the maximum number of capturing subpatterns in a recursion was greater
863        than the maximum at the outer level, the higher number was returned, but
864        with unset values at the outer level. The correct (outer level) value is
865        now given.
867    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
868        PCRE did not set those parentheses (unlike Perl). I have now found a way to
869        make it do so. The string so far is captured, making this feature
870        compatible with Perl.
872    23. The tests have been re-organized, adding tests 11 and 12, to make it
873        possible to check the Perl 5.10 features against Perl 5.10.
875    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
876        pattern matches a fixed length string. PCRE did not allow this; now it
877        does. Neither allows recursion.
879    25. I finally figured out how to implement a request to provide the minimum
880        length of subject string that was needed in order to match a given pattern.
881        (It was back references and recursion that I had previously got hung up
882        on.) This code has now been added to pcre_study(); it finds a lower bound
883        to the length of subject needed. It is not necessarily the greatest lower
884        bound, but using it to avoid searching strings that are too short does give
885        some useful speed-ups. The value is available to calling programs via
886        pcre_fullinfo().
888    26. While implementing 25, I discovered to my embarrassment that pcretest had
889        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
890        study optimizations had never been tested with that matching function.
891        Oops. What is worse, even when it was passed study data, there was a bug in
892        pcre_dfa_exec() that meant it never actually used it. Double oops. There
893        were also very few tests of studied patterns with pcre_dfa_exec().
895    27. If (?| is used to create subpatterns with duplicate numbers, they are now
896        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
897        on the other side of the coin, they are no longer allowed to have different
898        names, because these cannot be distinguished in PCRE, and this has caused
899        confusion. (This is a difference from Perl.)
901    28. When duplicate subpattern names are present (necessarily with different
902        numbers, as required by 27 above), and a test is made by name in a
903        conditional pattern, either for a subpattern having been matched, or for
904        recursion in such a pattern, all the associated numbered subpatterns are
905        tested, and the overall condition is true if the condition is true for any
906        one of them. This is the way Perl works, and is also more like the way
907        testing by number works.
910    Version 7.9 11-Apr-09
911    ---------------------
913    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
914        (pcretest), all targets were linked against these libraries. This included
915        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
916        libraries. This caused unwanted dependencies to be created. This problem
917        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
918        pcretest is linked with readline.
920    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
921        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
922        moved outside it again, because FALSE and TRUE are already defined in AIX,
923        but BOOL is not.
925    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
926        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
928    4.  The pcregrep documentation said spaces were inserted as well as colons (or
929        hyphens) following file names and line numbers when outputting matching
930        lines. This is not true; no spaces are inserted. I have also clarified the
931        wording for the --colour (or --color) option.
933    5.  In pcregrep, when --colour was used with -o, the list of matching strings
934        was not coloured; this is different to GNU grep, so I have changed it to be
935        the same.
937    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
938        each matching line was coloured. Now it goes on to look for further matches
939        of any of the test patterns, which is the same behaviour as GNU grep.
941    7.  A pattern that could match an empty string could cause pcregrep to loop; it
942        doesn't make sense to accept an empty string match in pcregrep, so I have
943        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
944        seems to be how GNU grep behaves.
946    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
947        start or after a newline", because the conditional assertion was not being
948        correctly handled. The rule now is that both the assertion and what follows
949        in the first alternative must satisfy the test.
951    9.  If auto-callout was enabled in a pattern with a conditional group whose
952        condition was an assertion, PCRE could crash during matching, both with
953        pcre_exec() and pcre_dfa_exec().
955    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
956        used for matching.
958    11. Unicode property support in character classes was not working for
959        characters (bytes) greater than 127 when not in UTF-8 mode.
961    12. Added the -M command line option to pcretest.
963    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
965    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
967    16. Added comments and documentation about mis-use of no_arg in the C++
968        wrapper.
970    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
971        from Martin Jerabek that uses macro names for all relevant character and
972        string constants.
974    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
975        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
976        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
977        these, but not everybody uses configure.
979    19. A conditional group that had only one branch was not being correctly
980        recognized as an item that could match an empty string. This meant that an
981        enclosing group might also not be so recognized, causing infinite looping
982        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
983        with the subject "ab", where knowledge that the repeated group can match
984        nothing is needed in order to break the loop.
986    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
987        exec(), but without supplying a callout function, matching went wrong.
989    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
990        leak if the size of the offset vector was greater than 30. When the vector
991        is smaller, the saved offsets during recursion go onto a local stack
992        vector, but for larger vectors malloc() is used. It was failing to free
993        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
994        error, in fact).
996    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
997        heapframe that is used only when UTF-8 support is enabled. This caused no
998        problem, but was untidy.
1000    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1001        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1002        included within another project.
1004    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1005        slightly modified by me:
1007          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1008              not building pcregrep.
1010          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1011              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1013    25. Forward references, both numeric and by name, in patterns that made use of
1014        duplicate group numbers, could behave incorrectly or give incorrect errors,
1015        because when scanning forward to find the reference group, PCRE was not
1016        taking into account the duplicate group numbers. A pattern such as
1017        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1019    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1020        the feature of a custom pointer more persuasive (as requested by a user).
1022    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1023        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1024        pre-defined.
1026    28. Added support for (*UTF8) at the start of a pattern.
1028    29. Arrange for flags added by the "release type" setting in CMake to be shown
1029        in the configuration summary.
1032    Version 7.8 05-Sep-08
1033    ---------------------
1035    1.  Replaced UCP searching code with optimized version as implemented for Ad
1036        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1037        stage table and inline lookup instead of a function, giving speed ups of 2
1038        to 5 times on some simple patterns that I tested. Permission was given to
1039        distribute the MultiStage2.py script that generates the tables (it's not in
1040        the tarball, but is in the Subversion repository).
1042    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1043        scripts.
1045    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1046        a group with a zero qualifier. The result of the study could be incorrect,
1047        or the function might crash, depending on the pattern.
1049    4.  Caseless matching was not working for non-ASCII characters in back
1050        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1051        It now works when Unicode Property Support is available.
1053    5.  In pcretest, an escape such as \x{de} in the data was always generating
1054        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1055        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1056        truncation.
1058    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1060    7.  Added two (int) casts to pcregrep when printing the difference of two
1061        pointers, in case they are 64-bit values.
1063    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1064        test 2 if it fails.
1066    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1067        and a #define of that name to empty if it is not externally set. This is to
1068        allow users of MSVC to set it if necessary.
1070    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1071        the convenience functions in the pcre_get.c source file.
1073    11. An option change at the start of a pattern that had top-level alternatives
1074        could cause overwriting and/or a crash. This command provoked a crash in
1075        some environments:
1077          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1079        This potential security problem was recorded as CVE-2008-2371.
1081    12. For a pattern where the match had to start at the beginning or immediately
1082        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1083        pcre_dfa_exec() could read past the end of the passed subject if there was
1084        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1085        pcretest so that it places the subject at the end of its malloc-ed buffer.
1087    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1088        exec() might read past the end of the data buffer in UTF-8 mode.
1090    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1091        the data contained the byte 0x85 as part of a UTF-8 character within its
1092        first line. This applied both to normal and DFA matching.
1094    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1095        /^[^d]*?$/8 failed to match "abc".
1097    16. Added a missing copyright notice to pcrecpp_internal.h.
1099    17. Make it more clear in the documentation that values returned from
1100        pcre_exec() in ovector are byte offsets, not character counts.
1102    18. Tidied a few places to stop certain compilers from issuing warnings.
1104    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1105        supplied by Stefan Weber. I made a further small update for 7.8 because
1106        there is a change of source arrangements: the pcre_searchfuncs.c module is
1107        replaced by pcre_ucd.c.
1110    Version 7.7 07-May-08
1111    ---------------------
1113    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1114        a string to a long long, pretend we don't even have a long long." This is
1115        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1117    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1118        pre-7.6 versions, which defined a global no_arg variable instead of putting
1119        it in the RE class. (See also #8 below.)
1121    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1122        Lopes.
1124    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1126        (1) The include/exclude patterns were being applied to the whole pathnames
1127            of files, instead of just to the final components.
1129        (2) If there was more than one level of directory, the subdirectories were
1130            skipped unless they satisfied the include/exclude conditions. This is
1131            inconsistent with GNU grep (and could even be seen as contrary to the
1132            pcregrep specification - which I improved to make it absolutely clear).
1133            The action now is always to scan all levels of directory, and just
1134            apply the include/exclude patterns to regular files.
1136    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1137        --exclude_dir in the tests to avoid scanning .svn directories.
1139    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1140        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1141        doesn't support NULs in patterns.
1143    7.  Added some missing "const"s to declarations of static tables in
1144        pcre_compile.c and pcre_dfa_exec.c.
1146    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1147        caused by fix #2  above. (Subsequently also a second patch to fix the
1148        first patch. And a third patch - this was a messy problem.)
1150    9.  Applied Craig's patch to remove the use of push_back().
1152    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1153        matching function regexec().
1155    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1156        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1157        references. PCRE supports relative numbers with this syntax (I don't think
1158        Oniguruma does).
1160    12. Previously, a group with a zero repeat such as (...){0} was completely
1161        omitted from the compiled regex. However, this means that if the group
1162        was called as a subroutine from elsewhere in the pattern, things went wrong
1163        (an internal error was given). Such groups are now left in the compiled
1164        pattern, with a new opcode that causes them to be skipped at execution
1165        time.
1167    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1168        to the way PCRE behaves:
1170        (a) A lone ] character is dis-allowed (Perl treats it as data).
1172        (b) A back reference to an unmatched subpattern matches an empty string
1173            (Perl fails the current match path).
1175        (c) A data ] in a character class must be notated as \] because if the
1176            first data character in a class is ], it defines an empty class. (In
1177            Perl it is not possible to have an empty class.) The empty class []
1178            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1179            The negative empty class [^] matches any one character, independently
1180            of the DOTALL setting.
1182    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1183        non-existent subpattern following a character class starting with ']' and
1184        containing () gave an internal compiling error instead of "reference to
1185        non-existent subpattern". Fortunately, when the pattern did exist, the
1186        compiled code was correct. (When scanning forwards to check for the
1187        existencd of the subpattern, it was treating the data ']' as terminating
1188        the class, so got the count wrong. When actually compiling, the reference
1189        was subsequently set up correctly.)
1191    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1192        it was being rejected as not supported by pcre_dfa_exec(), even though
1193        other assertions are supported. I have made pcre_dfa_exec() support
1194        (*FAIL).
1196    16. The implementation of 13c above involved the invention of a new opcode,
1197        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1198        cannot be changed at match time, I realized I could make a small
1199        improvement to matching performance by compiling OP_ALLANY instead of
1200        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1201        on the OP_ANY path.
1203    17. Compiling pcretest on Windows with readline support failed without the
1204        following two fixes: (1) Make the unistd.h include conditional on
1205        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1207    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1208        ncurses library to be included for pcretest when ReadLine support is
1209        requested, but also to allow for it to be overridden. This patch came from
1210        Daniel Bergström.
1212    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1213        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1214        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1215        spotting this.
1218    Version 7.6 28-Jan-08
1219    ---------------------
1221    1.  A character class containing a very large number of characters with
1222        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1223        overflow.
1225    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1226        HAVE_LONG_LONG is not defined.
1228    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1229        bring them up to date and include new features. This patch includes:
1231        - Fixed PH's badly added libz and libbz2 support.
1232        - Fixed a problem with static linking.
1233        - Added pcredemo. [But later removed - see 7 below.]
1234        - Fixed dftables problem and added an option.
1235        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1236            HAVE_LONG_LONG.
1237        - Added readline support for pcretest.
1238        - Added an listing of the option settings after cmake has run.
1240    4.  A user submitted a patch to Makefile that makes it easy to create
1241        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1242        Makefile.am that cause it to include this special target, without
1243        affecting anything else. Note that the same mingw target plus all
1244        the other distribution libraries and programs are now supported
1245        when configuring with CMake (see 6 below) instead of with
1246        Configure/Make.
1248    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1249        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1250        exported in the Windows port". It has not yet been confirmed that the patch
1251        solves the problem, but it does no harm.
1253    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1254        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1255        with CMake, and also correct the comment about stack recursion.
1257    7.  Remove the automatic building of pcredemo from the ./configure system and
1258        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1259        of a program that users should build themselves after PCRE is installed, so
1260        building it automatically is not really right. What is more, it gave
1261        trouble in some build environments.
1263    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1266    Version 7.5 10-Jan-08
1267    ---------------------
1269    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1270        values in parens when parsing an RE using the C++ wrapper."
1272    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1273        Characters greater than 255 were excluded from the class instead of being
1274        included.
1276    3.  The same bug as (2) above applied to negated POSIX classes such as
1277        [:^space:].
1279    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1280        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1281        I have changed it.
1283    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1284        first named subpattern) and a construct such as (?&a) would reference the
1285        first named subpattern whose name started with "a" (in other words, the
1286        length check was missing). Both these problems are fixed. "Subpattern name
1287        expected" is now given for (?&) (a zero-length name), and this patch also
1288        makes it give the same error for \k'' (previously it complained that that
1289        was a reference to a non-existent subpattern).
1291    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1292        this is right because (?- can be followed by option settings as well as by
1293        digits. I have, however, made the messages clearer.
1295    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1296        than the number used in the conditional) now cause a compile-time error.
1297        This is actually not compatible with Perl, which accepts such patterns, but
1298        treats the conditional as always being FALSE (as PCRE used to), but it
1299        seems to me that giving a diagnostic is better.
1301    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1302        and messages.
1304    9.  Fix two occurrences of "backslash" in comments that should have been
1305        "backspace".
1307    10. Remove two redundant lines of code that can never be obeyed (their function
1308        was moved elsewhere).
1310    11. The program that makes PCRE's Unicode character property table had a bug
1311        which caused it to generate incorrect table entries for sequences of
1312        characters that have the same character type, but are in different scripts.
1313        It amalgamated them into a single range, with the script of the first of
1314        them. In other words, some characters were in the wrong script. There were
1315        thirteen such cases, affecting characters in the following ranges:
1317          U+002b0 - U+002c1
1318          U+0060c - U+0060d
1319          U+0061e - U+00612
1320          U+0064b - U+0065e
1321          U+0074d - U+0076d
1322          U+01800 - U+01805
1323          U+01d00 - U+01d77
1324          U+01d9b - U+01dbf
1325          U+0200b - U+0200f
1326          U+030fc - U+030fe
1327          U+03260 - U+0327f
1328          U+0fb46 - U+0fbb1
1329          U+10450 - U+1049d
1331    12. The -o option (show only the matching part of a line) for pcregrep was not
1332        compatible with GNU grep in that, if there was more than one match in a
1333        line, it showed only the first of them. It now behaves in the same way as
1334        GNU grep.
1336    13. If the -o and -v options were combined for pcregrep, it printed a blank
1337        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1338        does the same. The return code can be used to tell if there were any
1339        non-matching lines.
1341    14. Added --file-offsets and --line-offsets to pcregrep.
1343    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1344        infinitely looping recursion. The bug was that positive lookaheads were not
1345        being skipped when checking for a possible empty match (negative lookaheads
1346        and both kinds of lookbehind were skipped).
1348    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1349        inclusion of <windows.h> to before rather than after the definition of
1350        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1352    17. Specifying a possessive quantifier with a specific limit for a Unicode
1353        character property caused pcre_compile() to compile bad code, which led at
1354        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1355        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1356        caused the error; without that there was no problem.
1358    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1360    19. Added --enable-pcretest-libreadline.
1362    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1363        RE::GlobalReplace(). As a result, the number of replacements returned was
1364        double what it should be. I removed one of the increments, but Craig sent a
1365        later patch that removed the other one (the right fix) and added unit tests
1366        that check the return values (which was not done before).
1368    21. Several CMake things:
1370        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1371            the names libpcre and libpcreposix, not just pcre and pcreposix.
1373        (2) The above change means that pcretest and pcregrep are now correctly
1374            linked with the newly-built libraries, not previously installed ones.
1378    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1379        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1380        UTF-8 newline character). The key issue is that the pattern starts .*;
1381        this means that the match must be either at the beginning, or after a
1382        newline. The bug was in the code for advancing after a failed match and
1383        checking that the new position followed a newline. It was not taking
1384        account of UTF-8 characters correctly.
1386    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1387        character classes. PCRE was not treating the sequence [:...:] as a
1388        character class unless the ... were all letters. Perl, however, seems to
1389        allow any characters between [: and :], though of course it rejects as
1390        unknown any "names" that contain non-letters, because all the known class
1391        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1392        for example, whereas PCRE did not - it did not recognize a POSIX character
1393        class. This seemed a bit dangerous, so the code has been changed to be
1394        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1395        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1396        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1397        Perl does, and where it didn't before.
1399    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1400        Windows environments %n is disabled by default.
1403    Version 7.4 21-Sep-07
1404    ---------------------
1406    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1407        means that a class such as [\s] counted as "explicit reference to CR or
1408        LF". That isn't really right - the whole point of the change was to try to
1409        help when there was an actual mention of one of the two characters. So now
1410        the change happens only if \r or \n (or a literal CR or LF) character is
1411        encountered.
1413    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1414        of both had grown to the point where there were only 3 bits left.
1415        Fortunately, there was spare space in the data structure, and so I have
1416        moved the internal flags into a new 16-bit field to free up more option
1417        bits.
1419    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1420        but did not set the internal JCHANGED flag - either of these is enough to
1421        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1422        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1423        start sets both bits.
1425    4.  Added options (at build time, compile time, exec time) to change \R from
1426        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1428    5.  doc/pcresyntax.html was missing from the distribution.
1430    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1431        compatibility, even though it is no longer used.
1433    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1434        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1435        windows.h file is present (where different names are used). [This was
1436        reversed later after testing - see 16 below.]
1438    8.  Changed all #include <config.h> to #include "config.h". There were also
1439        some further <pcre.h> cases that I changed to "pcre.h".
1441    9.  When pcregrep was used with the --colour option, it missed the line ending
1442        sequence off the lines that it output.
1444    10. It was pointed out to me that arrays of string pointers cause lots of
1445        relocations when a shared library is dynamically loaded. A technique of
1446        using a single long string with a table of offsets can drastically reduce
1447        these. I have refactored PCRE in four places to do this. The result is
1448        dramatic:
1450          Originally:                          290
1451          After changing UCP table:            187
1452          After changing error message table:   43
1453          After changing table of "verbs"       36
1454          After changing table of Posix names   22
1456        Thanks to the folks working on Gregex for glib for this insight.
1458    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1459        unicode-properties was also set.
1461    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1463    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1464        checked only for CRLF.
1466    14. Added casts to pcretest.c to avoid compiler warnings.
1468    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1470    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1471        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1472        entirely. This removes changes made in 7 above.
1474    17. The CMake files have been updated, and there is now more information about
1475        building with CMake in the NON-UNIX-USE document.
1478    Version 7.3 28-Aug-07
1479    ---------------------
1481     1. In the rejigging of the build system that eventually resulted in 7.1, the
1482        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1483        brackets there is not right, since it causes compilers to look for an
1484        installed pcre.h, not the version that is in the source that is being
1485        compiled (which of course may be different). I have changed it back to:
1487          #include "pcre.h"
1489        I have a vague recollection that the change was concerned with compiling in
1490        different directories, but in the new build system, that is taken care of
1491        by the VPATH setting the Makefile.
1493     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1494        when the subject happened to end in the byte 0x85 (e.g. if the last
1495        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1496        characters but of course it shouldn't be taken as a newline when it is part
1497        of another character. The bug was that, for an unlimited repeat of . in
1498        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1499        characters when looking for a newline.
1501     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1503     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1504        in debug output.
1506     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1507        long printing in the pcrecpp unittest when running under MinGW.
1509     6. ESC_K was left out of the EBCDIC table.
1511     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1512        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1513        limit also applies to "virtual nesting" when a pattern is recursive, and in
1514        this case 1000 isn't so big. I have been able to remove this limit at the
1515        expense of backing off one optimization in certain circumstances. Normally,
1516        when pcre_exec() would call its internal match() function recursively and
1517        immediately return the result unconditionally, it uses a "tail recursion"
1518        feature to save stack. However, when a subpattern that can match an empty
1519        string has an unlimited repetition quantifier, it no longer makes this
1520        optimization. That gives it a stack frame in which to save the data for
1521        checking that an empty string has been matched. Previously this was taken
1522        from the 1000-entry workspace that had been reserved. So now there is no
1523        explicit limit, but more stack is used.
1525     8. Applied Daniel's patches to solve problems with the import/export magic
1526        syntax that is required for Windows, and which was going wrong for the
1527        pcreposix and pcrecpp parts of the library. These were overlooked when this
1528        problem was solved for the main library.
1530     9. There were some crude static tests to avoid integer overflow when computing
1531        the size of patterns that contain repeated groups with explicit upper
1532        limits. As the maximum quantifier is 65535, the maximum group length was
1533        set at 30,000 so that the product of these two numbers did not overflow a
1534        32-bit integer. However, it turns out that people want to use groups that
1535        are longer than 30,000 bytes (though not repeat them that many times).
1536        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1537        made it possible to implement the integer overflow checks in a much more
1538        dynamic way, which I have now done. The artificial limitation on group
1539        length has been removed - we now have only the limit on the total length of
1540        the compiled pattern, which depends on the LINK_SIZE setting.
1542    10. Fixed a bug in the documentation for get/copy named substring when
1543        duplicate names are permitted. If none of the named substrings are set, the
1544        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1545        empty string.
1547    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1548        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1549        because the ] is interpreted as the first data character and the
1550        terminating ] is not found. PCRE has been made compatible with Perl in this
1551        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1552        cause memory overwriting.
1554    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1555        string has been matched (to stop an infinite loop). It was not recognizing
1556        a conditional subpattern that could match an empty string if that
1557        subpattern was within another subpattern. For example, it looped when
1558        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1559        condition was not nested. This bug has been fixed.
1561    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1562        past the start of the subject in the presence of bytes with the top bit
1563        set, for example "\x8aBCD".
1565    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1566        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1568    14. Optimized (?!) to (*FAIL).
1570    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1571        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1572        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1573        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1574        does: it's just the validity check that is more restrictive.
1576    16. Inserted checks for integer overflows during escape sequence (backslash)
1577        processing, and also fixed erroneous offset values for syntax errors during
1578        backslash processing.
1580    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1581        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1583    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1584        caused an overrun.
1586    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1587        something other than just ASCII characters) inside a group that had an
1588        unlimited repeat caused a loop at compile time (while checking to see
1589        whether the group could match an empty string).
1591    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1592        [\P{Any}] did so. (Error in the code for printing property names.)
1594    21. An orphan \E inside a character class could cause a crash.
1596    22. A repeated capturing bracket such as (A)? could cause a wild memory
1597        reference during compilation.
1599    23. There are several functions in pcre_compile() that scan along a compiled
1600        expression for various reasons (e.g. to see if it's fixed length for look
1601        behind). There were bugs in these functions when a repeated \p or \P was
1602        present in the pattern. These operators have additional parameters compared
1603        with \d, etc, and these were not being taken into account when moving along
1604        the compiled data. Specifically:
1606        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1607            length.
1609        (b) An item such as \pL+ within a repeated group could cause crashes or
1610            loops.
1612        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1613            "reference to non-existent subpattern" error.
1615        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1617    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1618        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1620    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1622    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1623        character were causing crashes (broken optimization).
1625    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1626        \p or \P) caused a compile-time loop.
1628    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1629        break. For example, the unstudied pattern [\r\n]A does not match the string
1630        "\r\nA" because change 7.0/46 below moves the current point on by two
1631        characters after failing to match at the start. However, the pattern \nA
1632        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1633        the same is true. There doesn't seem any very clean way out of this, but
1634        what I have chosen to do makes the common cases work: PCRE now takes note
1635        of whether there can be an explicit match for \r or \n anywhere in the
1636        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1637        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1638        pattern has explicit CR or LF references.
1640    29. Added (*CR) etc for changing newline setting at start of pattern.
1643    Version 7.2 19-Jun-07
1644    ---------------------
1646     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1647        which is apparently normally available under Windows.
1649     2. Re-jig the pcregrep tests with different newline settings in an attempt
1650        to make them independent of the local environment's newline setting.
1652     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1654     4. Some of the "internals" tests were previously cut out when the link size
1655        was not 2, because the output contained actual offsets. The recent new
1656        "Z" feature of pcretest means that these can be cut out, making the tests
1657        usable with all link sizes.
1659     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1660        stack recursion. This gives a massive performance boost under BSD, but just
1661        a small improvement under Linux. However, it saves one field in the frame
1662        in all cases.
1664     6. Added more features from the forthcoming Perl 5.10:
1666        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1667            recursion call. It refers to the nth most recently opened parentheses.
1669        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1670            to be opened parentheses.
1672        (c) Conditions that refer to capturing parentheses can be specified
1673            relatively, for example, (?(-2)... or (?(+3)...
1675        (d) \K resets the start of the current match so that everything before
1676            is not part of it.
1678        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1680        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1681            reference syntax.
1683        (g) (?| introduces a group in which the numbering of parentheses in each
1684            alternative starts with the same number.
1686        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1688     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1691     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1692        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1693        for detecting groups that can match an empty string.
1695     9. A pattern with a very large number of alternatives (more than several
1696        hundred) was running out of internal workspace during the pre-compile
1697        phase, where pcre_compile() figures out how much memory will be needed. A
1698        bit of new cunning has reduced the workspace needed for groups with
1699        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1700        workspace instead of running out of the 4096 that are available.
1702    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1704    11. Applied patch from Google to remove an optimization that didn't quite work.
1705        The report of the bug said:
1707          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1708          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1709          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1711    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1712        it matched the wrong number of bytes.
1715    Version 7.1 24-Apr-07
1716    ---------------------
1718     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1719        that is more "standard", making use of automake and other Autotools. There
1720        is some re-arrangement of the files and adjustment of comments consequent
1721        on this.
1723     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1724        for recursive directory scanning broke on some systems because the files
1725        are not scanned in any specific order and on different systems the order
1726        was different. A call to "sort" has been inserted into RunGrepTest for the
1727        approprate test as a short-term fix. In the longer term there may be an
1728        alternative.
1730     3. I had an email from Eric Raymond about problems translating some of PCRE's
1731        man pages to HTML (despite the fact that I distribute HTML pages, some
1732        people do their own conversions for various reasons). The problems
1733        concerned the use of low-level troff macros .br and .in. I have therefore
1734        removed all such uses from the man pages (some were redundant, some could
1735        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1736        HTML has been updated to handle .nf/.fi and to complain if it encounters
1737        .br or .in.
1739     4. Updated comments in configure.ac that get placed in config.h.in and also
1740        arranged for config.h to be included in the distribution, with the name
1741        config.h.generic, for the benefit of those who have to compile without
1742        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1744     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1745        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1746        makevp.bat for the current PCRE, using the additional files
1747        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1749     6. A Windows user reported a minor discrepancy with test 2, which turned out
1750        to be caused by a trailing space on an input line that had got lost in his
1751        copy. The trailing space was an accident, so I've just removed it.
1753     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1754        that is needed.
1756     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1757        as "const" (a) because they are and (b) because it helps the PHP
1758        maintainers who have recently made a script to detect big data structures
1759        in the php code that should be moved to the .rodata section. I remembered
1760        to update Builducptable as well, so it won't revert if ucptable.h is ever
1761        re-created.
1763     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1764        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1765        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1766        support is not required. This saves 1.5-2K of code, which is important in
1767        some applications.
1769        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1770        so as not to refer to the tables, even though these functions will never be
1771        called when UTF-8 support is disabled. Otherwise there are problems with a
1772        shared library.
1774    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1776        (a) It was defining its arguments as char * instead of void *.
1778        (b) It was assuming that all moves were upwards in memory; this was true
1779            a long time ago when I wrote it, but is no longer the case.
1781        The emulated memove() is provided for those environments that have neither
1782        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1783        is clearly not the case, as these two bugs were recently reported.
1785    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1786        and Detrail to create the HTML documentation, the .txt form of the man
1787        pages, and it removes trailing spaces from listed files. It also creates
1788        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1789        case, it wraps all the #defines with #ifndefs. This script should be run
1790        before "make dist".
1792    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1793        with Unicode property support.
1795        (a) For a maximizing quantifier, if the two different cases of the
1796            character were of different lengths in their UTF-8 codings (there are
1797            some cases like this - I found 11), and the matching function had to
1798            back up over a mixture of the two cases, it incorrectly assumed they
1799            were both the same length.
1801        (b) When PCRE was configured to use the heap rather than the stack for
1802            recursion during matching, it was not correctly preserving the data for
1803            the other case of a UTF-8 character when checking ahead for a match
1804            while processing a minimizing repeat. If the check also involved
1805            matching a wide character, but failed, corruption could cause an
1806            erroneous result when trying to check for a repeat of the original
1807            character.
1809    13. Some tidying changes to the testing mechanism:
1811        (a) The RunTest script now detects the internal link size and whether there
1812            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1813            values substituted by "configure". (The RunGrepTest script already did
1814            this for UTF-8.) The configure.ac script no longer substitutes the
1815            relevant variables.
1817        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1818            with length and offset values. This means that the output is different
1819            for different internal link sizes. Test 2 is skipped for link sizes
1820            other than 2 because of this, bypassing the problem. Unfortunately,
1821            there was also a test in test 3 (the locale tests) that used /B and
1822            failed for link sizes other than 2. Rather than cut the whole test out,
1823            I have added a new /Z option to pcretest that replaces the length and
1824            offset values with spaces. This is now used to make test 3 independent
1825            of link size. (Test 2 will be tidied up later.)
1827    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1828        segmentation fault instead of returning the appropriate error message.
1830    15. In multiline mode when the newline sequence was set to "any", the pattern
1831        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1832        This doesn't seem right; it now treats the CRLF combination as the line
1833        ending, and so does not match in that case. It's only a pattern such as ^$
1834        that would hit this one: something like ^ABC$ would have failed after \r
1835        and then tried again after \r\n.
1837    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1838        in an attempt to make files that differ only in their line terminators
1839        compare equal. This works on Linux.
1841    17. Under certain error circumstances pcregrep might try to free random memory
1842        as it exited. This is now fixed, thanks to valgrind.
1844    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1845        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1846        was because its rules for how to advance for /g after matching an empty
1847        string at the end of a line did not allow for this case. They now check for
1848        it specially.
1850    20. pcretest is supposed to handle patterns and data of any length, by
1851        extending its buffers when necessary. It was getting this wrong when the
1852        buffer for a data line had to be extended.
1854    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1855        CRLF as a newline sequence.
1857    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1858        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1859        I have nevertheless tidied it up.
1861    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1863    24. Added a man page for pcre-config.
1866    Version 7.0 19-Dec-06
1867    ---------------------
1869     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1870        moving to gcc 4.1.1.
1872     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1873        sys/time.h, which is documented as needed for this function. It doesn't
1874        seem to matter on Linux, but it showed up on some releases of OS X.
1876     3. It seems that there are systems where bytes whose values are greater than
1877        127 match isprint() in the "C" locale. The "C" locale should be the
1878        default when a C program starts up. In most systems, only ASCII printing
1879        characters match isprint(). This difference caused the output from pcretest
1880        to vary, making some of the tests fail. I have changed pcretest so that:
1882        (a) When it is outputting text in the compiled version of a pattern, bytes
1883            other than 32-126 are always shown as hex escapes.
1885        (b) When it is outputting text that is a matched part of a subject string,
1886            it does the same, unless a different locale has been set for the match
1887            (using the /L modifier). In this case, it uses isprint() to decide.
1889     4. Fixed a major bug that caused incorrect computation of the amount of memory
1890        required for a compiled pattern when options that changed within the
1891        pattern affected the logic of the preliminary scan that determines the
1892        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1893        that the computed length was too small. The symptoms of this bug were
1894        either the PCRE error "internal error: code overflow" from pcre_compile(),
1895        or a glibc crash with a message such as "pcretest: free(): invalid next
1896        size (fast)". Examples of patterns that provoked this bug (shown in
1897        pcretest format) are:
1899          /(?-x: )/x
1900          /(?x)(?-x: \s*#\s*)/
1901          /((?i)[\x{c0}])/8
1902          /(?i:[\x{c0}])/8
1904        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1905        is now done differently.
1907     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1908        wrapper classes; (b) implement a new function in the C++ scanner that is
1909        more efficient than the old way of doing things because it avoids levels of
1910        recursion in the regex matching; (c) add a paragraph to the documentation
1911        for the FullMatch() function.
1913     6. The escape sequence \n was being treated as whatever was defined as
1914        "newline". Not only was this contrary to the documentation, which states
1915        that \n is character 10 (hex 0A), but it also went horribly wrong when
1916        "newline" was defined as CRLF. This has been fixed.
1918     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1919        was being set to -1 for the "end of line" case (supposedly a value that no
1920        character can have). Though this value is never used (the check for end of
1921        line is "zero bytes in current character"), it caused compiler complaints.
1922        I've changed it to 0xffffffff.
1924     8. In pcre_version.c, the version string was being built by a sequence of
1925        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1926        string (as it is for production releases) called a macro with an empty
1927        argument. The C standard says the result of this is undefined. The gcc
1928        compiler treats it as an empty string (which was what was wanted) but it is
1929        reported that Visual C gives an error. The source has been hacked around to
1930        avoid this problem.
1932     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1933        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1934        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1935        of them did).
1937    10. Originally, pcretest opened its input and output without "b"; then I was
1938        told that "b" was needed in some environments, so it was added for release
1939        5.0 to both the input and output. (It makes no difference on Unix-like
1940        systems.) Later I was told that it is wrong for the input on Windows. I've
1941        now abstracted the modes into two macros, to make it easier to fiddle with
1942        them, and removed "b" from the input mode under Windows.
1944    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1946    12. Added -help and --help to pcretest as an official way of being reminded
1947        of the options.
1949    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1950        and pcrecpp.cc because they annoy compilers at high warning levels.
1952    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1954    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1955        scripts are not C programs :-) and which was not noticed because it works
1956        on Linux.
1958    16. pcretest is supposed to handle any length of pattern and data line (as one
1959        line or as a continued sequence of lines) by extending its input buffer if
1960        necessary. This feature was broken for very long pattern lines, leading to
1961        a string of junk being passed to pcre_compile() if the pattern was longer
1962        than about 50K.
1964    17. I have done a major re-factoring of the way pcre_compile() computes the
1965        amount of memory needed for a compiled pattern. Previously, there was code
1966        that made a preliminary scan of the pattern in order to do this. That was
1967        OK when PCRE was new, but as the facilities have expanded, it has become
1968        harder and harder to keep it in step with the real compile phase, and there
1969        have been a number of bugs (see for example, 4 above). I have now found a
1970        cunning way of running the real compile function in a "fake" mode that
1971        enables it to compute how much memory it would need, while actually only
1972        ever using a few hundred bytes of working memory and without too many
1973        tests of the mode. This should make future maintenance and development
1974        easier. A side effect of this work is that the limit of 200 on the nesting
1975        depth of parentheses has been removed (though this was never a serious
1976        limitation, I suspect). However, there is a downside: pcre_compile() now
1977        runs more slowly than before (30% or more, depending on the pattern). I
1978        hope this isn't a big issue. There is no effect on runtime performance.
1980    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1981        newline (only possible for the last line of a file) and it was a
1982        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1984    19. Added additional timing features to pcretest. (1) The -tm option now times
1985        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1986        separate command line item, by a number that specifies the number of
1987        repeats to use when timing. The default is 50000; this gives better
1988        precision, but takes uncomfortably long for very large patterns.
1990    20. Extended pcre_study() to be more clever in cases where a branch of a
1991        subpattern has no definite first character. For example, (a*|b*)[cd] would
1992        previously give no result from pcre_study(). Now it recognizes that the
1993        first character must be a, b, c, or d.
1995    21. There was an incorrect error "recursive call could loop indefinitely" if
1996        a subpattern (or the entire pattern) that was being tested for matching an
1997        empty string contained only one non-empty item after a nested subpattern.
1998        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1999        incorrectly, because the \d was being skipped in the check.
2001    22. The pcretest program now has a new pattern option /B and a command line
2002        option -b, which is equivalent to adding /B to every pattern. This causes
2003        it to show the compiled bytecode, without the additional information that
2004        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2005        is the same as /B/I).
2007    23. A new optimization is now able automatically to treat some sequences such
2008        as a*b as a*+b. More specifically, if something simple (such as a character
2009        or a simple class like \d) has an unlimited quantifier, and is followed by
2010        something that cannot possibly match the quantified thing, the quantifier
2011        is automatically "possessified".
2013    24. A recursive reference to a subpattern whose number was greater than 39
2014        went wrong under certain circumstances in UTF-8 mode. This bug could also
2015        have affected the operation of pcre_study().
2017    25. Realized that a little bit of performance could be had by replacing
2018        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2020    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2022    27. Possessive quantifiers such as a++ were previously implemented by turning
2023        them into atomic groups such as ($>a+). Now they have their own opcodes,
2024        which improves performance. This includes the automatically created ones
2025        from 23 above.
2027    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2028        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2029        the first matched character to be a colon. This applied both to named and
2030        numbered groups.
2032    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2034    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2035        building PCRE on Windows easier, so I have included it in the distribution.
2037    31. There is now a check in pcretest against a ridiculously large number being
2038        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2039        loop, the loop is abandoned.
2041    32. Forward references to subpatterns in conditions such as (?(2)...) where
2042        subpattern 2 is defined later cause pcre_compile() to search forwards in
2043        the pattern for the relevant set of parentheses. This search went wrong
2044        when there were unescaped parentheses in a character class, parentheses
2045        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2047    33. "Subroutine" calls and backreferences were previously restricted to
2048        referencing subpatterns earlier in the regex. This restriction has now
2049        been removed.
2051    34. Added a number of extra features that are going to be in Perl 5.10. On the
2052        whole, these are just syntactic alternatives for features that PCRE had
2053        previously implemented using the Python syntax or my own invention. The
2054        other formats are all retained for compatibility.
2056        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2057            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2058            also .NET compatible.
2060        (b) A recursion or subroutine call to a named group can now be defined as
2061            (?&name) as well as (?P>name).
2063        (c) A backreference to a named group can now be defined as \k<name> or
2064            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2065            5.10, are also .NET compatible.
2067        (d) A conditional reference to a named group can now use the syntax
2068            (?(<name>) or (?('name') as well as (?(name).
2070        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2071            groups (named and numbered) that are never evaluated inline, but can be
2072            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2073            is always false. There may be only one alternative in such a group.
2075        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2076            as the simple (?(R). The condition is true only if the most recent
2077            recursion is that of the given number or name. It does not search out
2078            through the entire recursion stack.
2080        (g) The escape \gN or \g{N} has been added, where N is a positive or
2081            negative number, specifying an absolute or relative reference.
2083    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2084        some "unreachable code" warnings.
2086    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2087        things, this adds five new scripts.
2089    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2090        There were also incompatibilities regarding the handling of \Q..\E inside
2091        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2092        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2094    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2095        matches an empty string, and forcibly breaks the loop. There were bugs in
2096        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2097        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2098        separate and independent bugs (that affected different cases) have been
2099        fixed.
2101    39. Refactored the code to abolish the use of different opcodes for small
2102        capturing bracket numbers. This is a tidy that I avoided doing when I
2103        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2104        The new approach is not only tidier, it makes it possible to reduce the
2105        memory needed to fix the previous bug (38).
2107    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2108        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2109        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2110        mode.
2112    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2113        report.
2115    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2116        copy construction and assignment in the C++ wrapper.
2118    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2119        couple of bugs that could have given wrong results in the "--newline=crlf"
2120        case.
2122    44. Added a number of casts and did some reorganization of signed/unsigned int
2123        variables following suggestions from Dair Grant. Also renamed the variable
2124        "this" as "item" because it is a C++ keyword.
2126    45. Arranged for dftables to add
2128          #include "pcre_internal.h"
2130        to pcre_chartables.c because without it, gcc 4.x may remove the array
2131        definition from the final binary if PCRE is built into a static library and
2132        dead code stripping is activated.
2134    46. For an unanchored pattern, if a match attempt fails at the start of a
2135        newline sequence, and the newline setting is CRLF or ANY, and the next two
2136        characters are CRLF, advance by two characters instead of one.
2139    Version 6.7 04-Jul-06
2140    ---------------------
2142     1. In order to handle tests when input lines are enormously long, pcretest has
2143        been re-factored so that it automatically extends its buffers when
2144        necessary. The code is crude, but this _is_ just a test program. The
2145        default size has been increased from 32K to 50K.
2147     2. The code in pcre_study() was using the value of the re argument before
2148        testing it for NULL. (Of course, in any sensible call of the function, it
2149        won't be NULL.)
2151     3. The memmove() emulation function in pcre_internal.h, which is used on
2152        systems that lack both memmove() and bcopy() - that is, hardly ever -
2153        was missing a "static" storage class specifier.
2155     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2156        containing an extended class (one that cannot be represented by a bitmap
2157        because it contains high-valued characters or Unicode property items, e.g.
2158        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2159        pattern, but PCRE should not loop if you do not (it no longer does).
2160        [Detail: two cases were found: (a) a repeated subpattern containing an
2161        extended class; (b) a recursive reference to a subpattern that followed a
2162        previous extended class. It wasn't skipping over the extended class
2163        correctly when UTF-8 mode was not set.]
2165     5. A negated single-character class was not being recognized as fixed-length
2166        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2167        compile error "lookbehind assertion is not fixed length".
2169     6. The RunPerlTest auxiliary script was showing an unexpected difference
2170        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2171        write a Perl script that can interpret lines of an input file either as
2172        byte characters or as UTF-8, which is what "perltest" was being required to
2173        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2174        can't do is switch easily at run time between having the "use utf8;" pragma
2175        or not. In the end, I fudged it by using the RunPerlTest script to insert
2176        "use utf8;" explicitly for the UTF-8 tests.
2178     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2179        the end of the subject string, contrary to the documentation and to what
2180        Perl does. This was true of both matching functions. Now it matches only at
2181        the start of the subject and immediately after *internal* newlines.
2183     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2184        a pointer to an int instead of a pointer to an unsigned long int. This
2185        caused problems on 64-bit systems.
2187     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2188        instance of the 'standard' template library not being so standard".
2190    10. There was no check on the number of named subpatterns nor the maximum
2191        length of a subpattern name. The product of these values is used to compute
2192        the size of the memory block for a compiled pattern. By supplying a very
2193        long subpattern name and a large number of named subpatterns, the size
2194        computation could be caused to overflow. This is now prevented by limiting
2195        the length of names to 32 characters, and the number of named subpatterns
2196        to 10,000.
2198    11. Subpatterns that are repeated with specific counts have to be replicated in
2199        the compiled pattern. The size of memory for this was computed from the
2200        length of the subpattern and the repeat count. The latter is limited to
2201        65535, but there was no limit on the former, meaning that integer overflow
2202        could in principle occur. The compiled length of a repeated subpattern is
2203        now limited to 30,000 bytes in order to prevent this.
2205    12. Added the optional facility to have named substrings with the same name.
2207    13. Added the ability to use a named substring as a condition, using the
2208        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2209        are numbers (not recommended). Forward references are permitted.
2211    14. Added forward references in named backreferences (if you see what I mean).
2213    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2214        pattern could run off the end of the subject. For example, the pattern
2215        "(?s)(.{1,5})"8 did this with the subject "ab".
2217    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2218        PCRE_CASELESS was set when matching characters that were quantified with ?
2219        or *.
2221    17. A character class other than a single negated character that had a minimum
2222        but no maximum quantifier - for example [ab]{6,} - was not handled
2223        correctly by pce_dfa_exec(). It would match only one character.
2225    18. A valid (though odd) pattern that looked like a POSIX character
2226        class but used an invalid character after [ (for example [[,abc,]]) caused
2227        pcre_compile() to give the error "Failed: internal error: code overflow" or
2228        in some cases to crash with a glibc free() error. This could even happen if
2229        the pattern terminated after [[ but there just happened to be a sequence of
2230        letters, a binary zero, and a closing ] in the memory that followed.
2232    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2233        over the years. Originally (before any Unicode support), just the bottom 8
2234        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2235        output from "man perlunicode" includes this:
2237          The regular expression compiler produces polymorphic opcodes.  That
2238          is, the pattern adapts to the data and automatically switches to
2239          the Unicode character scheme when presented with Unicode data--or
2240          instead uses a traditional byte scheme when presented with byte
2241          data.
2243        Sadly, a wide octal escape does not cause a switch, and in a string with
2244        no other multibyte characters, these octal escapes are treated as before.
2245        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2246        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2247        Unicode string.
2249        I have not perpetrated such confusion in PCRE. Up till now, it took just
2250        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2251        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2252        translate to the appropriate multibyte character.
2254    29. Applied some refactoring to reduce the number of warnings from Microsoft
2255        and Borland compilers. This has included removing the fudge introduced
2256        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2257        a warning about an unused variable.
2259    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2260        characters since release 4.0, because Perl (from release 5.004) does not.
2261        [Or at least, is documented not to: some releases seem to be in conflict
2262        with the documentation.] However, when a pattern was studied with
2263        pcre_study() and all its branches started with \s, PCRE still included VT
2264        as a possible starting character. Of course, this did no harm; it just
2265        caused an unnecessary match attempt.
2267    22. Removed a now-redundant internal flag bit that recorded the fact that case
2268        dependency changed within the pattern. This was once needed for "required
2269        byte" processing, but is no longer used. This recovers a now-scarce options
2270        bit. Also moved the least significant internal flag bit to the most-
2271        significant bit of the word, which was not previously used (hangover from
2272        the days when it was an int rather than a uint) to free up another bit for
2273        the future.
2275    23. Added support for CRLF line endings as well as CR and LF. As well as the
2276        default being selectable at build time, it can now be changed at runtime
2277        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2278        specify that it is scanning data with non-default line endings.
2280    24. Changed the definition of CXXLINK to make it agree with the definition of
2281        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2283    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2284        recursions. This makes a big different to stack usage for some patterns.
2286    26. If a subpattern containing a named recursion or subroutine reference such
2287        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2288        the space required for the compiled pattern went wrong and gave too small a
2289        value. Depending on the environment, this could lead to "Failed: internal
2290        error: code overflow at offset 49" or "glibc detected double free or
2291        corruption" errors.
2293    27. Applied patches from Google (a) to support the new newline modes and (b) to
2294        advance over multibyte UTF-8 characters in GlobalReplace.
2296    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2297        difference for some implementation of PCRE in some Windows version.
2299    29. Added some extra testing facilities to pcretest:
2301        \q<number>   in a data line sets the "match limit" value
2302        \Q<number>   in a data line sets the "match recursion limt" value
2303        -S <number>  sets the stack size, where <number> is in megabytes
2305        The -S option isn't available for Windows.
2308    Version 6.6 06-Feb-06
2309    ---------------------
2311     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2312        in pcreposix.h. I have copied the definition from pcre.h.
2314     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2315        because pcre.h is no longer a built file.
2317     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2318        not normally included in the compiled code.
2321  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
2322  ---------------------  ---------------------

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