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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.1 12-Mar-07  Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
13    Version 8.20 21-Oct-2011
14    ------------------------
16    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
17        a POSIX class. After further experiments with Perl, which convinced me that
18        Perl has bugs and confusions, a closing square bracket is no longer allowed
19        in a POSIX name. This bug also affected patterns with classes that started
20        with full stops.
22    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
23        captured substring, but while checking the failing first alternative,
24        substring 1 is temporarily captured. If the output vector supplied to
25        pcre_exec() was not big enough for this capture, the yield of the function
26        was still zero ("insufficient space for captured substrings"). This cannot
27        be totally fixed without adding another stack variable, which seems a lot
28        of expense for a edge case. However, I have improved the situation in cases
29        such as /(a)(b)x|abc/ matched against "abc", where the return code
30        indicates that fewer than the maximum number of slots in the ovector have
31        been set.
33    3.  Related to (2) above: when there are more back references in a pattern than
34        slots in the output vector, pcre_exec() uses temporary memory during
35        matching, and copies in the captures as far as possible afterwards. It was
36        using the entire output vector, but this conflicts with the specification
37        that only 2/3 is used for passing back captured substrings. Now it uses
38        only the first 2/3, for compatibility. This is, of course, another edge
39        case.
41    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
42        main code base, and can be used by building with --enable-jit. When this is
43        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
44        runtime --no-jit option is given.
46    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
47        ovector, the return from the function was zero, implying that there were
48        other matches that did not fit. The correct "exactly full" value is now
49        returned.
51    6.  If a subpattern that was called recursively or as a subroutine contained
52        (*PRUNE) or any other control that caused it to give a non-standard return,
53        invalid errors such as "Error -26 (nested recursion at the same subject
54        position)" or even infinite loops could occur.
56    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
57        computing the minimum length on reaching *ACCEPT, and so ended up with the
58        wrong value of 1 rather than 0. Further investigation indicates that
59        computing a minimum subject length in the presence of *ACCEPT is difficult
60        (think back references, subroutine calls), and so I have changed the code
61        so that no minimum is registered for a pattern that contains *ACCEPT.
63    8.  If (*THEN) was present in the first (true) branch of a conditional group,
64        it was not handled as intended. [But see 16 below.]
66    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
67        Sheri Pierce.
69    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
70        the first byte in a match must be "a".
72    11. Change 17 for 8.13 increased the recursion depth for patterns like
73        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
74        pattern contains any instances of (*THEN). If it does not, the old
75        optimizations are restored. It would be nice to do this on a per-group
76        basis, but at the moment that is not feasible.
78    12. In some environments, the output of pcretest -C is CRLF terminated. This
79        broke RunTest's code that checks for the link size. A single white space
80        character after the value is now allowed for.
82    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
83        For "fr", it uses the Windows-specific input and output files.
85    14. If (*THEN) appeared in a group that was called recursively or as a
86        subroutine, it did not work as intended. [But see next item.]
88    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
89        pattern fragments (but not containing any | characters). If A and B are
90        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
91        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
92        D. In other words, Perl considers parentheses that do not contain any |
93        characters to be part of a surrounding alternative, whereas PCRE was
94        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
95        differently. PCRE now behaves in the same way as Perl, except in the case
96        of subroutine/recursion calls such as (?1) which have in any case always
97        been different (but PCRE had them first :-).
99    16. Related to 15 above: Perl does not treat the | in a conditional group as
100        creating alternatives. Such a group is treated in the same way as an
101        ordinary group without any | characters when processing (*THEN). PCRE has
102        been changed to match Perl's behaviour.
104    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
105        RunGrepTest script failed.
107    18. Change 22 for version 13 caused atomic groups to use more stack. This is
108        inevitable for groups that contain captures, but it can lead to a lot of
109        stack use in large patterns. The old behaviour has been restored for atomic
110        groups that do not contain any capturing parentheses.
112    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
113        suppress the check for a minimum subject length at run time. (If it was
114        given to pcre_exec() or pcre_dfa_exec() it did work.)
116    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
117        fail to work when decoding hex characters in data strings in EBCDIC
118        environments.
120    21. It appears that in at least one Mac OS environment, the isxdigit() function
121        is implemented as a macro that evaluates to its argument more than once,
122        contravening the C 90 Standard (I haven't checked a later standard). There
123        was an instance in pcretest which caused it to go wrong when processing
124        \x{...} escapes in subject strings. The has been rewritten to avoid using
125        things like p++ in the argument of isxdigit().
128    Version 8.13 16-Aug-2011
129    ------------------------
131    1.  The Unicode data tables have been updated to Unicode 6.0.0.
133    2.  Two minor typos in pcre_internal.h have been fixed.
135    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
136        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
137        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
139    4.  There were a number of related bugs in the code for matching backrefences
140        caselessly in UTF-8 mode when codes for the characters concerned were
141        different numbers of bytes. For example, U+023A and U+2C65 are an upper
142        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
143        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
144        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
145        2-byte code at the end of the subject (it thought there wasn't enough data
146        left).
148    5.  Comprehensive information about what went wrong is now returned by
149        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
150        as the output vector has at least 2 elements. The offset of the start of
151        the failing character and a reason code are placed in the vector.
153    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
154        now returned is for the first byte of the failing character, instead of the
155        last byte inspected. This is an incompatible change, but I hope it is small
156        enough not to be a problem. It makes the returned offset consistent with
157        pcre_exec() and pcre_dfa_exec().
159    7.  pcretest now gives a text phrase as well as the error number when
160        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
161        failure, the offset and reason code are output.
163    8.  When \R was used with a maximizing quantifier it failed to skip backwards
164        over a \r\n pair if the subsequent match failed. Instead, it just skipped
165        back over a single character (\n). This seems wrong (because it treated the
166        two characters as a single entity when going forwards), conflicts with the
167        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
168        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
169        has been changed.
171    9.  Some internal refactoring has changed the processing so that the handling
172        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
173        time (the PCRE_DOTALL option was changed this way some time ago: version
174        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
175        which was always a bit of a fudge. It also means that there is one less
176        argument for the match() function, which reduces its stack requirements
177        slightly. This change also fixes an incompatibility with Perl: the pattern
178        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
180    10. More internal refactoring has drastically reduced the number of recursive
181        calls to match() for possessively repeated groups such as (abc)++ when
182        using pcre_exec().
184    11. While implementing 10, a number of bugs in the handling of groups were
185        discovered and fixed:
187        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
188        (a|)*(?1) gave a compile-time internal error.
189        ((a|)+)+  did not notice that the outer group could match an empty string.
190        (^a|^)+   was not marked as anchored.
191        (.*a|.*)+ was not marked as matching at start or after a newline.
193    12. Yet more internal refactoring has removed another argument from the match()
194        function. Special calls to this function are now indicated by setting a
195        value in a variable in the "match data" data block.
197    13. Be more explicit in pcre_study() instead of relying on "default" for
198        opcodes that mean there is no starting character; this means that when new
199        ones are added and accidentally left out of pcre_study(), testing should
200        pick them up.
202    14. The -s option of pcretest has been documented for ages as being an old
203        synonym of -m (show memory usage). I have changed it to mean "force study
204        for every regex", that is, assume /S for every regex. This is similar to -i
205        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
206        using it. It makes it easier to run collections of tests with and without
207        study enabled, and thereby test pcre_study() more easily. All the standard
208        tests are now run with and without -s (but some patterns can be marked as
209        "never study" - see 20 below).
211    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
212        restoration of the capturing data to the outer values was not happening
213        correctly.
215    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
216        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
217        pattern had matched an empty string, and so incorrectly returned a no
218        match.
220    17. There was optimizing code for the last branch of non-capturing parentheses,
221        and also for the obeyed branch of a conditional subexpression, which used
222        tail recursion to cut down on stack usage. Unfortunately, now that there is
223        the possibility of (*THEN) occurring in these branches, tail recursion is
224        no longer possible because the return has to be checked for (*THEN). These
225        two optimizations have therefore been removed. [But see 8.20/11 above.]
227    18. If a pattern containing \R was studied, it was assumed that \R always
228        matched two bytes, thus causing the minimum subject length to be
229        incorrectly computed because \R can also match just one byte.
231    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
232        was incorrectly computed.
234    20. If /S is present twice on a test pattern in pcretest input, it now
235        *disables* studying, thereby overriding the use of -s on the command line
236        (see 14 above). This is necessary for one or two tests to keep the output
237        identical in both cases.
239    21. When (*ACCEPT) was used in an assertion that matched an empty string and
240        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
242    22. When an atomic group that contained a capturing parenthesis was
243        successfully matched, but the branch in which it appeared failed, the
244        capturing was not being forgotten if a higher numbered group was later
245        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
246        group 1 to "a", when in fact it should be unset. This applied to multi-
247        branched capturing and non-capturing groups, repeated or not, and also to
248        positive assertions (capturing in negative assertions does not happen
249        in PCRE) and also to nested atomic groups.
251    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
252        subject after a captured substring, to make it easier to tell which of a
253        number of identical substrings has been captured.
255    24. The way atomic groups are processed by pcre_exec() has been changed so that
256        if they are repeated, backtracking one repetition now resets captured
257        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
258        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
259        "aaa". Previously, it would have been "a". As part of this code
260        refactoring, the way recursive calls are handled has also been changed.
262    25. If an assertion condition captured any substrings, they were not passed
263        back unless some other capturing happened later. For example, if
264        (?(?=(a))a) was matched against "a", no capturing was returned.
266    26. When studying a pattern that contained subroutine calls or assertions,
267        the code for finding the minimum length of a possible match was handling
268        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
269        group 1 called group 2 while simultaneously a separate group 2 called group
270        1). A stack overflow occurred in this case. I have fixed this by limiting
271        the recursion depth to 10.
273    27. Updated RunTest.bat in the distribution to the version supplied by Tom
274        Fortmann. This supports explicit test numbers on the command line, and has
275        argument validation and error reporting.
277    28. An instance of \X with an unlimited repeat could fail if at any point the
278        first character it looked at was a mark character.
280    29. Some minor code refactoring concerning Unicode properties and scripts
281        should reduce the stack requirement of match() slightly.
283    30. Added the '=' option to pcretest to check the setting of unused capturing
284        slots at the end of the pattern, which are documented as being -1, but are
285        not included in the return count.
287    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
288        compiled something random. Now it gives a compile-time error (as does
289        Perl).
291    32. A *MARK encountered during the processing of a positive assertion is now
292        recorded and passed back (compatible with Perl).
294    33. If --only-matching or --colour was set on a pcregrep call whose pattern
295        had alternative anchored branches, the search for a second match in a line
296        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
297        matched the line "0102" twice. The same bug affected patterns that started
298        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
299        twice.
301    34. Previously, PCRE did not allow quantification of assertions. However, Perl
302        does, and because of capturing effects, quantifying parenthesized
303        assertions may at times be useful. Quantifiers are now allowed for
304        parenthesized assertions.
306    35. A minor code tidy in pcre_compile() when checking options for \R usage.
308    36. \g was being checked for fancy things in a character class, when it should
309        just be a literal "g".
311    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
312        appearance of a nested POSIX class supersedes an apparent external class.
313        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
314        unescaped square brackets may also appear as part of class names. For
315        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
316        more like Perl. (But see 8.20/1 above.)
318    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
319        was because it thought it was \N{name}, which is not supported).
321    39. Add minix to OS list not supporting the -S option in pcretest.
323    40. PCRE tries to detect cases of infinite recursion at compile time, but it
324        cannot analyze patterns in sufficient detail to catch mutual recursions
325        such as ((?1))((?2)). There is now a runtime test that gives an error if a
326        subgroup is called recursively as a subpattern for a second time at the
327        same position in the subject string. In previous releases this might have
328        been caught by the recursion limit, or it might have run out of stack.
330    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
331        happen only once. PCRE was, however incorrectly giving a compile time error
332        "recursive call could loop indefinitely" because it cannot analyze the
333        pattern in sufficient detail. The compile time test no longer happens when
334        PCRE is compiling a conditional subpattern, but actual runaway loops are
335        now caught at runtime (see 40 above).
337    42. It seems that Perl allows any characters other than a closing parenthesis
338        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
339        has been changed to be the same.
341    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
342        as not to get warnings when autogen.sh is called. Also changed
343        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
345    44. To help people who use pcregrep to scan files containing exceedingly long
346        lines, the following changes have been made:
348        (a) The default value of the buffer size parameter has been increased from
349            8K to 20K. (The actual buffer used is three times this size.)
351        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
352            PCRE is built.
354        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
355            to be set at run time.
357        (d) Numerical values in pcregrep options can be followed by K or M, for
358            example --buffer-size=50K.
360        (e) If a line being scanned overflows pcregrep's buffer, an error is now
361            given and the return code is set to 2.
363    45. Add a pointer to the latest mark to the callout data block.
365    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
366        partial match of an empty string instead of no match. This was specific to
367        the use of ".".
369    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
370        complete match instead of a partial match. This bug was dependent on both
371        the PCRE_UTF8 and PCRE_DOTALL options being set.
373    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
374        starting byte set, because \b was not being ignored.
377    Version 8.12 15-Jan-2011
378    ------------------------
380    1.  Fixed some typos in the markup of the man pages, and wrote a script that
381        checks for such things as part of the documentation building process.
383    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
384        --match-limit and --recursion-limit options (added for 8.11). In
385        particular, this made one of the standard tests fail. (The integer value
386        went into the wrong half of a long int.)
388    3.  If the --colour option was given to pcregrep with -v (invert match), it
389        did strange things, either producing crazy output, or crashing. It should,
390        of course, ignore a request for colour when reporting lines that do not
391        match.
393    4.  Another pcregrep bug caused similar problems if --colour was specified with
394        -M (multiline) and the pattern match finished with a line ending.
396    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
397        matched in multiline mode, the following line was shown as part of the
398        match. This seems wrong, so I have changed it.
400    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
401        the check for further matches in the same line (so they could be coloured)
402        to overrun the end of the current line. If another match was found, it was
403        incorrectly shown (and then shown again when found in the next line).
405    7.  If pcregrep was compiled under Windows, there was a reference to the
406        function pcregrep_exit() before it was defined. I am assuming this was
407        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
408        reported by a user. I've moved the definition above the reference.
411    Version 8.11 10-Dec-2010
412    ------------------------
414    1.  (*THEN) was not working properly if there were untried alternatives prior
415        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
416        backtracked to try for "b" instead of moving to the next alternative branch
417        at the same level (in this case, to look for "c"). The Perl documentation
418        is clear that when (*THEN) is backtracked onto, it goes to the "next
419        alternative in the innermost enclosing group".
421    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
422        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
423        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
424        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
425        (*THEN).
427    3.  If \s appeared in a character class, it removed the VT character from
428        the class, even if it had been included by some previous item, for example
429        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
430        of \s, but is part of the POSIX "space" class.)
432    4.  A partial match never returns an empty string (because you can always
433        match an empty string at the end of the subject); however the checking for
434        an empty string was starting at the "start of match" point. This has been
435        changed to the "earliest inspected character" point, because the returned
436        data for a partial match starts at this character. This means that, for
437        example, /(?<=abc)def/ gives a partial match for the subject "abc"
438        (previously it gave "no match").
440    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
441        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
442        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
443        has an implication that the given string is incomplete (because a partial
444        match is preferred over a full match). For this reason, these items now
445        give a partial match in this situation. [Aside: previously, the one case
446        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
447        match rather than a full match, which was wrong by the old rules, but is
448        now correct.]
450    6.  There was a bug in the handling of #-introduced comments, recognized when
451        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
452        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
453        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
454        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
455        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
456        places in pcre_compile().
458    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
459        comments when looking ahead for named forward references to subpatterns,
460        the only newline sequence it recognized was NL. It now handles newlines
461        according to the set newline convention.
463    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
464        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
465        cater for a lack of strerror(). These oversights have been fixed.
467    9.  Added --match-limit and --recursion-limit to pcregrep.
469    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
471    11. When the -o option was used, pcregrep was setting a return code of 1, even
472        when matches were found, and --line-buffered was not being honoured.
474    12. Added an optional parentheses number to the -o and --only-matching options
475        of pcregrep.
477    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
478        can match an empty string. The code to do it in pcretest and pcredemo
479        needed fixing:
481        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
482            only one byte after an empty string match just before CRLF (this case
483            just got forgotten; "any" and "anycrlf" were OK).
485        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
486            mode when an empty string match preceded an ASCII character followed by
487            a non-ASCII character. (The code for advancing by one character rather
488            than one byte was nonsense.)
490        (c) The pcredemo.c sample program did not have any code at all to handle
491            the cases when CRLF is a valid newline sequence.
493    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
494        as a starting offset was within the subject string. There is now a new
495        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
496        negative or greater than the length of the string. In order to test this,
497        pcretest is extended to allow the setting of negative starting offsets.
499    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
500        starting offset points to the beginning of a UTF-8 character was
501        unnecessarily clumsy. I tidied it up.
503    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
504        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
506    17. Nobody had reported that the --include_dir option, which was added in
507        release 7.7 should have been called --include-dir (hyphen, not underscore)
508        for compatibility with GNU grep. I have changed it to --include-dir, but
509        left --include_dir as an undocumented synonym, and the same for
510        --exclude-dir, though that is not available in GNU grep, at least as of
511        release 2.5.4.
513    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
514        characters from a string of bytes) have been redefined so as not to use
515        loops, in order to improve performance in some environments. At the same
516        time, I abstracted some of the common code into auxiliary macros to save
517        repetition (this should not affect the compiled code).
519    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
520        compile-time error is now given if \c is not followed by an ASCII
521        character, that is, a byte less than 128. (In EBCDIC mode, the code is
522        different, and any byte value is allowed.)
524    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
525        START_OPTIMIZE option, which is now allowed at compile time - but just
526        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
527        to pcregrep and other applications that have no direct access to PCRE
528        options. The new /Y option in pcretest sets this option when calling
529        pcre_compile().
531    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
532        back references. Groups containing recursive back references were forced to
533        be atomic by that change, but in the case of named groups, the amount of
534        memory required was incorrectly computed, leading to "Failed: internal
535        error: code overflow". This has been fixed.
537    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
538        pcretest.c, to avoid build problems in some Borland environments.
541    Version 8.10 25-Jun-2010
542    ------------------------
544    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
545        THEN.
547    2.  (*ACCEPT) was not working when inside an atomic group.
549    3.  Inside a character class, \B is treated as a literal by default, but
550        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
551        causes the error). The code is unchanged, but I tidied the documentation.
553    4.  Inside a character class, PCRE always treated \R and \X as literals,
554        whereas Perl faults them if its -w option is set. I have changed PCRE so
555        that it faults them when PCRE_EXTRA is set.
557    5.  Added support for \N, which always matches any character other than
558        newline. (It is the same as "." when PCRE_DOTALL is not set.)
560    6.  When compiling pcregrep with newer versions of gcc which may have
561        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
562        declared with attribute warn_unused_result" were given. Just casting the
563        result to (void) does not stop the warnings; a more elaborate fudge is
564        needed. I've used a macro to implement this.
566    7.  Minor change to pcretest.c to avoid a compiler warning.
568    8.  Added four artifical Unicode properties to help with an option to make
569        \s etc use properties (see next item). The new properties are: Xan
570        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
572    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
573        use Unicode properties. (*UCP) at the start of a pattern can be used to set
574        this option. Modified pcretest to add /W to test this facility. Added
575        REG_UCP to make it available via the POSIX interface.
577    10. Added --line-buffered to pcregrep.
579    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
580        studied, and the match started with a letter with a code point greater than
581        127 whose first byte was different to the first byte of the other case of
582        the letter, the other case of this starting letter was not recognized
583        (#976).
585    12. If a pattern that was studied started with a repeated Unicode property
586        test, for example, \p{Nd}+, there was the theoretical possibility of
587        setting up an incorrect bitmap of starting bytes, but fortunately it could
588        not have actually happened in practice until change 8 above was made (it
589        added property types that matched character-matching opcodes).
591    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
592        possible starting bytes for non-anchored patterns.
594    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
595        \R, and also a number of cases that involve Unicode properties, both
596        explicit and implicit when PCRE_UCP is set.
598    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
599        input, it could crash or give wrong results if characters with values
600        greater than 0xc0 were present in the subject string. (Detail: it assumed
601        UTF-8 input when processing these items.)
603    16. Added a lot of (int) casts to avoid compiler warnings in systems where
604        size_t is 64-bit (#991).
606    17. Added a check for running out of memory when PCRE is compiled with
607        --disable-stack-for-recursion (#990).
609    18. If the last data line in a file for pcretest does not have a newline on
610        the end, a newline was missing in the output.
612    19. The default pcre_chartables.c file recognizes only ASCII characters (values
613        less than 128) in its various bitmaps. However, there is a facility for
614        generating tables according to the current locale when PCRE is compiled. It
615        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
616        characters, are recognized by isspace() and therefore were getting set in
617        these tables, and indeed these tables seem to approximate to ISO 8859. This
618        caused a problem in UTF-8 mode when pcre_study() was used to create a list
619        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
620        which of course cannot start UTF-8 characters. I have changed the code so
621        that only real ASCII characters (less than 128) and the correct starting
622        bytes for UTF-8 encodings are set for characters greater than 127 when in
623        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
624        altogether.)
626    20. Added the /T option to pcretest so as to be able to run tests with non-
627        standard character tables, thus making it possible to include the tests
628        used for 19 above in the standard set of tests.
630    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
631        reference to a subpattern the other side of a comment that contains an
632        opening parenthesis caused either an internal compiling error, or a
633        reference to the wrong subpattern.
636    Version 8.02 19-Mar-2010
637    ------------------------
639    1.  The Unicode data tables have been updated to Unicode 5.2.0.
641    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
642        configured.
644    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
645        original author of that file, following a query about its status.
647    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
648        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
650    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
651        quantifier applied to a forward-referencing subroutine call, could compile
652        incorrect code or give the error "internal error: previously-checked
653        referenced subpattern not found".
655    6.  Both MS Visual Studio and Symbian OS have problems with initializing
656        variables to point to external functions. For these systems, therefore,
657        pcre_malloc etc. are now initialized to local functions that call the
658        relevant global functions.
660    7.  There were two entries missing in the vectors called coptable and poptable
661        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
662        I've fixed the data, and added a kludgy way of testing at compile time that
663        the lengths are correct (equal to the number of opcodes).
665    8.  Following on from 7, I added a similar kludge to check the length of the
666        eint vector in pcreposix.c.
668    9.  Error texts for pcre_compile() are held as one long string to avoid too
669        much relocation at load time. To find a text, the string is searched,
670        counting zeros. There was no check for running off the end of the string,
671        which could happen if a new error number was added without updating the
672        string.
674    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
676    11. \K was not working if it appeared in an atomic group or in a group that
677        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
678        \K is "not well defined" if used in an assertion. PCRE now accepts it if
679        the assertion is positive, but not if it is negative.
681    12. Change 11 fortuitously reduced the size of the stack frame used in the
682        "match()" function of pcre_exec.c by one pointer. Forthcoming
683        implementation of support for (*MARK) will need an extra pointer on the
684        stack; I have reserved it now, so that the stack frame size does not
685        decrease.
687    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
688        item in branch that calls a recursion is a subroutine call - as in the
689        second branch in the above example - was incorrectly given the compile-
690        time error "recursive call could loop indefinitely" because pcre_compile()
691        was not correctly checking the subroutine for matching a non-empty string.
693    14. The checks for overrunning compiling workspace could trigger after an
694        overrun had occurred. This is a "should never occur" error, but it can be
695        triggered by pathological patterns such as hundreds of nested parentheses.
696        The checks now trigger 100 bytes before the end of the workspace.
698    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
701    Version 8.01 19-Jan-2010
702    ------------------------
704    1.  If a pattern contained a conditional subpattern with only one branch (in
705        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
706        computed the wrong minimum data length (which is of course zero for such
707        subpatterns). This could cause incorrect "no match" results.
709    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
710        the pattern is reset in the first branch, pcre_compile() failed with
711        "internal error: code overflow at offset...". This happened only when
712        the reset was to the original external option setting. (An optimization
713        abstracts leading options settings into an external setting, which was the
714        cause of this.)
716    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
717        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
718        assertion pattern did not match (meaning that the assertion was true), it
719        was incorrectly treated as false if the SKIP had been reached during the
720        matching. This also applied to assertions used as conditions.
722    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
723        assertion subpattern, including such a pattern used as a condition,
724        unpredictable results occurred, instead of the error return
727    5.  The C++ GlobalReplace function was not working like Perl for the special
728        situation when an empty string is matched. It now does the fancy magic
729        stuff that is necessary.
731    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
732        removed. (These were left over from very, very early versions of PCRE.)
734    7.  Some cosmetic changes to the code to make life easier when compiling it
735        as part of something else:
737        (a) Change DEBUG to PCRE_DEBUG.
739        (b) In pcre_compile(), rename the member of the "branch_chain" structure
740            called "current" as "current_branch", to prevent a collision with the
741            Linux macro when compiled as a kernel module.
743        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
744            prevent a collision with the Linux macro when compiled as a kernel
745            module.
747    8.  In pcre_compile() there are some checks for integer overflows that used to
748        cast potentially large values to (double). This has been changed to that
749        when building, a check for int64_t is made, and if it is found, it is used
750        instead, thus avoiding the use of floating point arithmetic. (There is no
751        other use of FP in PCRE.) If int64_t is not found, the fallback is to
752        double.
754    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
755        2005 (difference between two addresses compared to an unsigned value).
757    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
758        custom one, because of the following reported problem in Windows:
760          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
761              under Win32.
762          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
763              therefore missing the function definition.
764          - The compiler thus generates a "C" signature for the test function.
765          - The linker fails to find the "C" function.
766          - PCRE fails to configure if asked to do so against libbz2.
768    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
769        messages were output:
771          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
772          rerunning libtoolize, to keep the correct libtool macros in-tree.
773          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
775        I have done both of these things.
777    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
778        most of the time, it *can* run out if it is given a pattern that contains a
779        runaway infinite recursion. I updated the discussion in the pcrestack man
780        page.
782    13. Now that we have gone to the x.xx style of version numbers, the minor
783        version may start with zero. Using 08 or 09 is a bad idea because users
784        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
785        interpreted as invalid octal numbers. I've updated the previous comment in
786        configure.ac, and also added a check that gives an error if 08 or 09 are
787        used.
789    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
790        causing partial matching to fail when the end of the subject matched \W
791        in a UTF-8 pattern where \W was quantified with a minimum of 3.
793    15. There were some discrepancies between the declarations in pcre_internal.h
794        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
795        their definitions. The declarations used "const uschar *" and the
796        definitions used USPTR. Even though USPTR is normally defined as "const
797        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
798        reported that: "This difference in casting confuses some C++ compilers, for
799        example, SunCC recognizes above declarations as different functions and
800        generates broken code for hbpcre." I have changed the declarations to use
801        USPTR.
803    16. GNU libtool is named differently on some systems. The autogen.sh script now
804        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
805        (FreeBSD).
807    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
808        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
809        comment: "Figure out how to create a longlong from a string: strtoll and
810        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
811        instance, but it only takes 2 args instead of 3!"
813    18. A subtle bug concerned with back references has been fixed by a change of
814        specification, with a corresponding code fix. A pattern such as
815        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
816        refers, was giving matches when it shouldn't. For example, xa=xaaa would
817        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
818        same bug. Such groups have to be quantified to be useful, or contained
819        inside another quantified group. (If there's no repetition, the reference
820        can never match.) The problem arises because, having left the group and
821        moved on to the rest of the pattern, a later failure that backtracks into
822        the group uses the captured value from the final iteration of the group
823        rather than the correct earlier one. I have fixed this in PCRE by forcing
824        any group that contains a reference to itself to be an atomic group; that
825        is, there cannot be any backtracking into it once it has completed. This is
826        similar to recursive and subroutine calls.
829    Version 8.00 19-Oct-09
830    ----------------------
832    1.  The table for translating pcre_compile() error codes into POSIX error codes
833        was out-of-date, and there was no check on the pcre_compile() error code
834        being within the table. This could lead to an OK return being given in
835        error.
837    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
838        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
839        in a Windows environment.
841    3.  The pcregrep --count option prints the count for each file even when it is
842        zero, as does GNU grep. However, pcregrep was also printing all files when
843        --files-with-matches was added. Now, when both options are given, it prints
844        counts only for those files that have at least one match. (GNU grep just
845        prints the file name in this circumstance, but including the count seems
846        more useful - otherwise, why use --count?) Also ensured that the
847        combination -clh just lists non-zero counts, with no names.
849    4.  The long form of the pcregrep -F option was incorrectly implemented as
850        --fixed_strings instead of --fixed-strings. This is an incompatible change,
851        but it seems right to fix it, and I didn't think it was worth preserving
852        the old behaviour.
854    5.  The command line items --regex=pattern and --regexp=pattern were not
855        recognized by pcregrep, which required --regex pattern or --regexp pattern
856        (with a space rather than an '='). The man page documented the '=' forms,
857        which are compatible with GNU grep; these now work.
859    6.  No libpcreposix.pc file was created for pkg-config; there was just
860        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
862    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
863        when UCP support is not needed, by modifying the Python script that
864        generates it from Unicode data files. This should not matter if the module
865        is correctly used as a library, but I received one complaint about 50K of
866        unwanted data. My guess is that the person linked everything into his
867        program rather than using a library. Anyway, it does no harm.
869    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
870        was a minimum greater than 1 for a wide character in a possessive
871        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
872        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
873        character. Chaos in the form of incorrect output or a compiling loop could
874        result.
876    9.  The restrictions on what a pattern can contain when partial matching is
877        requested for pcre_exec() have been removed. All patterns can now be
878        partially matched by this function. In addition, if there are at least two
879        slots in the offset vector, the offset of the earliest inspected character
880        for the match and the offset of the end of the subject are set in them when
881        PCRE_ERROR_PARTIAL is returned.
883    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
884        synonymous with PCRE_PARTIAL, for backwards compatibility, and
885        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
886        and may be more useful for multi-segment matching.
888    11. Partial matching with pcre_exec() is now more intuitive. A partial match
889        used to be given if ever the end of the subject was reached; now it is
890        given only if matching could not proceed because another character was
891        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
892        string "Z", which now yields "no match" instead of "partial match". In the
893        case of pcre_dfa_exec(), "no match" is given if every matching path for the
894        final character ended with (*FAIL).
896    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
897        if the pattern had a "must contain" character that was already found in the
898        earlier partial match, unless partial matching was again requested. For
899        example, with the pattern /dog.(body)?/, the "must contain" character is
900        "g". If the first part-match was for the string "dog", restarting with
901        "sbody" failed. This bug has been fixed.
903    13. The string returned by pcre_dfa_exec() after a partial match has been
904        changed so that it starts at the first inspected character rather than the
905        first character of the match. This makes a difference only if the pattern
906        starts with a lookbehind assertion or \b or \B (\K is not supported by
907        pcre_dfa_exec()). It's an incompatible change, but it makes the two
908        matching functions compatible, and I think it's the right thing to do.
910    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
911        so that the demonstration program is easily available in environments where
912        PCRE has not been installed from source.
914    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
915        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
916        library.
918    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
919        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
920        is not the first non-POSIX option to be added. Clearly some people find
921        these options useful.
923    17. If a caller to the POSIX matching function regexec() passes a non-zero
924        value for nmatch with a NULL value for pmatch, the value of
925        nmatch is forced to zero.
927    18. RunGrepTest did not have a test for the availability of the -u option of
928        the diff command, as RunTest does. It now checks in the same way as
929        RunTest, and also checks for the -b option.
931    19. If an odd number of negated classes containing just a single character
932        interposed, within parentheses, between a forward reference to a named
933        subpattern and the definition of the subpattern, compilation crashed with
934        an internal error, complaining that it could not find the referenced
935        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
936        [The bug was that it was starting one character too far in when skipping
937        over the character class, thus treating the ] as data rather than
938        terminating the class. This meant it could skip too much.]
940    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
941        /g option in pcretest when the pattern contains \K, which makes it possible
942        to have an empty string match not at the start, even when the pattern is
943        anchored. Updated pcretest and pcredemo to use this option.
945    21. If the maximum number of capturing subpatterns in a recursion was greater
946        than the maximum at the outer level, the higher number was returned, but
947        with unset values at the outer level. The correct (outer level) value is
948        now given.
950    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
951        PCRE did not set those parentheses (unlike Perl). I have now found a way to
952        make it do so. The string so far is captured, making this feature
953        compatible with Perl.
955    23. The tests have been re-organized, adding tests 11 and 12, to make it
956        possible to check the Perl 5.10 features against Perl 5.10.
958    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
959        pattern matches a fixed length string. PCRE did not allow this; now it
960        does. Neither allows recursion.
962    25. I finally figured out how to implement a request to provide the minimum
963        length of subject string that was needed in order to match a given pattern.
964        (It was back references and recursion that I had previously got hung up
965        on.) This code has now been added to pcre_study(); it finds a lower bound
966        to the length of subject needed. It is not necessarily the greatest lower
967        bound, but using it to avoid searching strings that are too short does give
968        some useful speed-ups. The value is available to calling programs via
969        pcre_fullinfo().
971    26. While implementing 25, I discovered to my embarrassment that pcretest had
972        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
973        study optimizations had never been tested with that matching function.
974        Oops. What is worse, even when it was passed study data, there was a bug in
975        pcre_dfa_exec() that meant it never actually used it. Double oops. There
976        were also very few tests of studied patterns with pcre_dfa_exec().
978    27. If (?| is used to create subpatterns with duplicate numbers, they are now
979        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
980        on the other side of the coin, they are no longer allowed to have different
981        names, because these cannot be distinguished in PCRE, and this has caused
982        confusion. (This is a difference from Perl.)
984    28. When duplicate subpattern names are present (necessarily with different
985        numbers, as required by 27 above), and a test is made by name in a
986        conditional pattern, either for a subpattern having been matched, or for
987        recursion in such a pattern, all the associated numbered subpatterns are
988        tested, and the overall condition is true if the condition is true for any
989        one of them. This is the way Perl works, and is also more like the way
990        testing by number works.
993    Version 7.9 11-Apr-09
994    ---------------------
996    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
997        (pcretest), all targets were linked against these libraries. This included
998        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
999        libraries. This caused unwanted dependencies to be created. This problem
1000        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1001        pcretest is linked with readline.
1003    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1004        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1005        moved outside it again, because FALSE and TRUE are already defined in AIX,
1006        but BOOL is not.
1008    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1009        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1011    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1012        hyphens) following file names and line numbers when outputting matching
1013        lines. This is not true; no spaces are inserted. I have also clarified the
1014        wording for the --colour (or --color) option.
1016    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1017        was not coloured; this is different to GNU grep, so I have changed it to be
1018        the same.
1020    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1021        each matching line was coloured. Now it goes on to look for further matches
1022        of any of the test patterns, which is the same behaviour as GNU grep.
1024    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1025        doesn't make sense to accept an empty string match in pcregrep, so I have
1026        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1027        seems to be how GNU grep behaves.
1029    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1030        start or after a newline", because the conditional assertion was not being
1031        correctly handled. The rule now is that both the assertion and what follows
1032        in the first alternative must satisfy the test.
1034    9.  If auto-callout was enabled in a pattern with a conditional group whose
1035        condition was an assertion, PCRE could crash during matching, both with
1036        pcre_exec() and pcre_dfa_exec().
1038    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1039        used for matching.
1041    11. Unicode property support in character classes was not working for
1042        characters (bytes) greater than 127 when not in UTF-8 mode.
1044    12. Added the -M command line option to pcretest.
1046    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1048    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1050    16. Added comments and documentation about mis-use of no_arg in the C++
1051        wrapper.
1053    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1054        from Martin Jerabek that uses macro names for all relevant character and
1055        string constants.
1057    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1058        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1059        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1060        these, but not everybody uses configure.
1062    19. A conditional group that had only one branch was not being correctly
1063        recognized as an item that could match an empty string. This meant that an
1064        enclosing group might also not be so recognized, causing infinite looping
1065        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1066        with the subject "ab", where knowledge that the repeated group can match
1067        nothing is needed in order to break the loop.
1069    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1070        exec(), but without supplying a callout function, matching went wrong.
1072    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1073        leak if the size of the offset vector was greater than 30. When the vector
1074        is smaller, the saved offsets during recursion go onto a local stack
1075        vector, but for larger vectors malloc() is used. It was failing to free
1076        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1077        error, in fact).
1079    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1080        heapframe that is used only when UTF-8 support is enabled. This caused no
1081        problem, but was untidy.
1083    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1084        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1085        included within another project.
1087    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1088        slightly modified by me:
1090          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1091              not building pcregrep.
1093          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1094              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1096    25. Forward references, both numeric and by name, in patterns that made use of
1097        duplicate group numbers, could behave incorrectly or give incorrect errors,
1098        because when scanning forward to find the reference group, PCRE was not
1099        taking into account the duplicate group numbers. A pattern such as
1100        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1102    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1103        the feature of a custom pointer more persuasive (as requested by a user).
1105    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1106        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1107        pre-defined.
1109    28. Added support for (*UTF8) at the start of a pattern.
1111    29. Arrange for flags added by the "release type" setting in CMake to be shown
1112        in the configuration summary.
1115    Version 7.8 05-Sep-08
1116    ---------------------
1118    1.  Replaced UCP searching code with optimized version as implemented for Ad
1119        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1120        stage table and inline lookup instead of a function, giving speed ups of 2
1121        to 5 times on some simple patterns that I tested. Permission was given to
1122        distribute the MultiStage2.py script that generates the tables (it's not in
1123        the tarball, but is in the Subversion repository).
1125    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1126        scripts.
1128    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1129        a group with a zero qualifier. The result of the study could be incorrect,
1130        or the function might crash, depending on the pattern.
1132    4.  Caseless matching was not working for non-ASCII characters in back
1133        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1134        It now works when Unicode Property Support is available.
1136    5.  In pcretest, an escape such as \x{de} in the data was always generating
1137        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1138        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1139        truncation.
1141    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1143    7.  Added two (int) casts to pcregrep when printing the difference of two
1144        pointers, in case they are 64-bit values.
1146    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1147        test 2 if it fails.
1149    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1150        and a #define of that name to empty if it is not externally set. This is to
1151        allow users of MSVC to set it if necessary.
1153    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1154        the convenience functions in the pcre_get.c source file.
1156    11. An option change at the start of a pattern that had top-level alternatives
1157        could cause overwriting and/or a crash. This command provoked a crash in
1158        some environments:
1160          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1162        This potential security problem was recorded as CVE-2008-2371.
1164    12. For a pattern where the match had to start at the beginning or immediately
1165        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1166        pcre_dfa_exec() could read past the end of the passed subject if there was
1167        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1168        pcretest so that it places the subject at the end of its malloc-ed buffer.
1170    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1171        exec() might read past the end of the data buffer in UTF-8 mode.
1173    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1174        the data contained the byte 0x85 as part of a UTF-8 character within its
1175        first line. This applied both to normal and DFA matching.
1177    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1178        /^[^d]*?$/8 failed to match "abc".
1180    16. Added a missing copyright notice to pcrecpp_internal.h.
1182    17. Make it more clear in the documentation that values returned from
1183        pcre_exec() in ovector are byte offsets, not character counts.
1185    18. Tidied a few places to stop certain compilers from issuing warnings.
1187    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1188        supplied by Stefan Weber. I made a further small update for 7.8 because
1189        there is a change of source arrangements: the pcre_searchfuncs.c module is
1190        replaced by pcre_ucd.c.
1193    Version 7.7 07-May-08
1194    ---------------------
1196    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1197        a string to a long long, pretend we don't even have a long long." This is
1198        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1200    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1201        pre-7.6 versions, which defined a global no_arg variable instead of putting
1202        it in the RE class. (See also #8 below.)
1204    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1205        Lopes.
1207    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1209        (1) The include/exclude patterns were being applied to the whole pathnames
1210            of files, instead of just to the final components.
1212        (2) If there was more than one level of directory, the subdirectories were
1213            skipped unless they satisfied the include/exclude conditions. This is
1214            inconsistent with GNU grep (and could even be seen as contrary to the
1215            pcregrep specification - which I improved to make it absolutely clear).
1216            The action now is always to scan all levels of directory, and just
1217            apply the include/exclude patterns to regular files.
1219    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1220        --exclude_dir in the tests to avoid scanning .svn directories.
1222    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1223        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1224        doesn't support NULs in patterns.
1226    7.  Added some missing "const"s to declarations of static tables in
1227        pcre_compile.c and pcre_dfa_exec.c.
1229    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1230        caused by fix #2  above. (Subsequently also a second patch to fix the
1231        first patch. And a third patch - this was a messy problem.)
1233    9.  Applied Craig's patch to remove the use of push_back().
1235    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1236        matching function regexec().
1238    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1239        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1240        references. PCRE supports relative numbers with this syntax (I don't think
1241        Oniguruma does).
1243    12. Previously, a group with a zero repeat such as (...){0} was completely
1244        omitted from the compiled regex. However, this means that if the group
1245        was called as a subroutine from elsewhere in the pattern, things went wrong
1246        (an internal error was given). Such groups are now left in the compiled
1247        pattern, with a new opcode that causes them to be skipped at execution
1248        time.
1250    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1251        to the way PCRE behaves:
1253        (a) A lone ] character is dis-allowed (Perl treats it as data).
1255        (b) A back reference to an unmatched subpattern matches an empty string
1256            (Perl fails the current match path).
1258        (c) A data ] in a character class must be notated as \] because if the
1259            first data character in a class is ], it defines an empty class. (In
1260            Perl it is not possible to have an empty class.) The empty class []
1261            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1262            The negative empty class [^] matches any one character, independently
1263            of the DOTALL setting.
1265    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1266        non-existent subpattern following a character class starting with ']' and
1267        containing () gave an internal compiling error instead of "reference to
1268        non-existent subpattern". Fortunately, when the pattern did exist, the
1269        compiled code was correct. (When scanning forwards to check for the
1270        existencd of the subpattern, it was treating the data ']' as terminating
1271        the class, so got the count wrong. When actually compiling, the reference
1272        was subsequently set up correctly.)
1274    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1275        it was being rejected as not supported by pcre_dfa_exec(), even though
1276        other assertions are supported. I have made pcre_dfa_exec() support
1277        (*FAIL).
1279    16. The implementation of 13c above involved the invention of a new opcode,
1280        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1281        cannot be changed at match time, I realized I could make a small
1282        improvement to matching performance by compiling OP_ALLANY instead of
1283        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1284        on the OP_ANY path.
1286    17. Compiling pcretest on Windows with readline support failed without the
1287        following two fixes: (1) Make the unistd.h include conditional on
1288        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1290    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1291        ncurses library to be included for pcretest when ReadLine support is
1292        requested, but also to allow for it to be overridden. This patch came from
1293        Daniel Bergström.
1295    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1296        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1297        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1298        spotting this.
1301    Version 7.6 28-Jan-08
1302    ---------------------
1304    1.  A character class containing a very large number of characters with
1305        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1306        overflow.
1308    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1309        HAVE_LONG_LONG is not defined.
1311    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1312        bring them up to date and include new features. This patch includes:
1314        - Fixed PH's badly added libz and libbz2 support.
1315        - Fixed a problem with static linking.
1316        - Added pcredemo. [But later removed - see 7 below.]
1317        - Fixed dftables problem and added an option.
1318        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1319            HAVE_LONG_LONG.
1320        - Added readline support for pcretest.
1321        - Added an listing of the option settings after cmake has run.
1323    4.  A user submitted a patch to Makefile that makes it easy to create
1324        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1325        Makefile.am that cause it to include this special target, without
1326        affecting anything else. Note that the same mingw target plus all
1327        the other distribution libraries and programs are now supported
1328        when configuring with CMake (see 6 below) instead of with
1329        Configure/Make.
1331    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1332        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1333        exported in the Windows port". It has not yet been confirmed that the patch
1334        solves the problem, but it does no harm.
1336    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1337        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1338        with CMake, and also correct the comment about stack recursion.
1340    7.  Remove the automatic building of pcredemo from the ./configure system and
1341        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1342        of a program that users should build themselves after PCRE is installed, so
1343        building it automatically is not really right. What is more, it gave
1344        trouble in some build environments.
1346    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1349    Version 7.5 10-Jan-08
1350    ---------------------
1352    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1353        values in parens when parsing an RE using the C++ wrapper."
1355    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1356        Characters greater than 255 were excluded from the class instead of being
1357        included.
1359    3.  The same bug as (2) above applied to negated POSIX classes such as
1360        [:^space:].
1362    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1363        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1364        I have changed it.
1366    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1367        first named subpattern) and a construct such as (?&a) would reference the
1368        first named subpattern whose name started with "a" (in other words, the
1369        length check was missing). Both these problems are fixed. "Subpattern name
1370        expected" is now given for (?&) (a zero-length name), and this patch also
1371        makes it give the same error for \k'' (previously it complained that that
1372        was a reference to a non-existent subpattern).
1374    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1375        this is right because (?- can be followed by option settings as well as by
1376        digits. I have, however, made the messages clearer.
1378    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1379        than the number used in the conditional) now cause a compile-time error.
1380        This is actually not compatible with Perl, which accepts such patterns, but
1381        treats the conditional as always being FALSE (as PCRE used to), but it
1382        seems to me that giving a diagnostic is better.
1384    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1385        and messages.
1387    9.  Fix two occurrences of "backslash" in comments that should have been
1388        "backspace".
1390    10. Remove two redundant lines of code that can never be obeyed (their function
1391        was moved elsewhere).
1393    11. The program that makes PCRE's Unicode character property table had a bug
1394        which caused it to generate incorrect table entries for sequences of
1395        characters that have the same character type, but are in different scripts.
1396        It amalgamated them into a single range, with the script of the first of
1397        them. In other words, some characters were in the wrong script. There were
1398        thirteen such cases, affecting characters in the following ranges:
1400          U+002b0 - U+002c1
1401          U+0060c - U+0060d
1402          U+0061e - U+00612
1403          U+0064b - U+0065e
1404          U+0074d - U+0076d
1405          U+01800 - U+01805
1406          U+01d00 - U+01d77
1407          U+01d9b - U+01dbf
1408          U+0200b - U+0200f
1409          U+030fc - U+030fe
1410          U+03260 - U+0327f
1411          U+0fb46 - U+0fbb1
1412          U+10450 - U+1049d
1414    12. The -o option (show only the matching part of a line) for pcregrep was not
1415        compatible with GNU grep in that, if there was more than one match in a
1416        line, it showed only the first of them. It now behaves in the same way as
1417        GNU grep.
1419    13. If the -o and -v options were combined for pcregrep, it printed a blank
1420        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1421        does the same. The return code can be used to tell if there were any
1422        non-matching lines.
1424    14. Added --file-offsets and --line-offsets to pcregrep.
1426    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1427        infinitely looping recursion. The bug was that positive lookaheads were not
1428        being skipped when checking for a possible empty match (negative lookaheads
1429        and both kinds of lookbehind were skipped).
1431    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1432        inclusion of <windows.h> to before rather than after the definition of
1433        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1435    17. Specifying a possessive quantifier with a specific limit for a Unicode
1436        character property caused pcre_compile() to compile bad code, which led at
1437        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1438        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1439        caused the error; without that there was no problem.
1441    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1443    19. Added --enable-pcretest-libreadline.
1445    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1446        RE::GlobalReplace(). As a result, the number of replacements returned was
1447        double what it should be. I removed one of the increments, but Craig sent a
1448        later patch that removed the other one (the right fix) and added unit tests
1449        that check the return values (which was not done before).
1451    21. Several CMake things:
1453        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1454            the names libpcre and libpcreposix, not just pcre and pcreposix.
1456        (2) The above change means that pcretest and pcregrep are now correctly
1457            linked with the newly-built libraries, not previously installed ones.
1461    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1462        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1463        UTF-8 newline character). The key issue is that the pattern starts .*;
1464        this means that the match must be either at the beginning, or after a
1465        newline. The bug was in the code for advancing after a failed match and
1466        checking that the new position followed a newline. It was not taking
1467        account of UTF-8 characters correctly.
1469    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1470        character classes. PCRE was not treating the sequence [:...:] as a
1471        character class unless the ... were all letters. Perl, however, seems to
1472        allow any characters between [: and :], though of course it rejects as
1473        unknown any "names" that contain non-letters, because all the known class
1474        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1475        for example, whereas PCRE did not - it did not recognize a POSIX character
1476        class. This seemed a bit dangerous, so the code has been changed to be
1477        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1478        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1479        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1480        Perl does, and where it didn't before.
1482    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1483        Windows environments %n is disabled by default.
1486    Version 7.4 21-Sep-07
1487    ---------------------
1489    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1490        means that a class such as [\s] counted as "explicit reference to CR or
1491        LF". That isn't really right - the whole point of the change was to try to
1492        help when there was an actual mention of one of the two characters. So now
1493        the change happens only if \r or \n (or a literal CR or LF) character is
1494        encountered.
1496    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1497        of both had grown to the point where there were only 3 bits left.
1498        Fortunately, there was spare space in the data structure, and so I have
1499        moved the internal flags into a new 16-bit field to free up more option
1500        bits.
1502    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1503        but did not set the internal JCHANGED flag - either of these is enough to
1504        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1505        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1506        start sets both bits.
1508    4.  Added options (at build time, compile time, exec time) to change \R from
1509        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1511    5.  doc/pcresyntax.html was missing from the distribution.
1513    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1514        compatibility, even though it is no longer used.
1516    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1517        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1518        windows.h file is present (where different names are used). [This was
1519        reversed later after testing - see 16 below.]
1521    8.  Changed all #include <config.h> to #include "config.h". There were also
1522        some further <pcre.h> cases that I changed to "pcre.h".
1524    9.  When pcregrep was used with the --colour option, it missed the line ending
1525        sequence off the lines that it output.
1527    10. It was pointed out to me that arrays of string pointers cause lots of
1528        relocations when a shared library is dynamically loaded. A technique of
1529        using a single long string with a table of offsets can drastically reduce
1530        these. I have refactored PCRE in four places to do this. The result is
1531        dramatic:
1533          Originally:                          290
1534          After changing UCP table:            187
1535          After changing error message table:   43
1536          After changing table of "verbs"       36
1537          After changing table of Posix names   22
1539        Thanks to the folks working on Gregex for glib for this insight.
1541    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1542        unicode-properties was also set.
1544    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1546    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1547        checked only for CRLF.
1549    14. Added casts to pcretest.c to avoid compiler warnings.
1551    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1553    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1554        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1555        entirely. This removes changes made in 7 above.
1557    17. The CMake files have been updated, and there is now more information about
1558        building with CMake in the NON-UNIX-USE document.
1561    Version 7.3 28-Aug-07
1562    ---------------------
1564     1. In the rejigging of the build system that eventually resulted in 7.1, the
1565        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1566        brackets there is not right, since it causes compilers to look for an
1567        installed pcre.h, not the version that is in the source that is being
1568        compiled (which of course may be different). I have changed it back to:
1570          #include "pcre.h"
1572        I have a vague recollection that the change was concerned with compiling in
1573        different directories, but in the new build system, that is taken care of
1574        by the VPATH setting the Makefile.
1576     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1577        when the subject happened to end in the byte 0x85 (e.g. if the last
1578        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1579        characters but of course it shouldn't be taken as a newline when it is part
1580        of another character. The bug was that, for an unlimited repeat of . in
1581        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1582        characters when looking for a newline.
1584     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1586     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1587        in debug output.
1589     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1590        long printing in the pcrecpp unittest when running under MinGW.
1592     6. ESC_K was left out of the EBCDIC table.
1594     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1595        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1596        limit also applies to "virtual nesting" when a pattern is recursive, and in
1597        this case 1000 isn't so big. I have been able to remove this limit at the
1598        expense of backing off one optimization in certain circumstances. Normally,
1599        when pcre_exec() would call its internal match() function recursively and
1600        immediately return the result unconditionally, it uses a "tail recursion"
1601        feature to save stack. However, when a subpattern that can match an empty
1602        string has an unlimited repetition quantifier, it no longer makes this
1603        optimization. That gives it a stack frame in which to save the data for
1604        checking that an empty string has been matched. Previously this was taken
1605        from the 1000-entry workspace that had been reserved. So now there is no
1606        explicit limit, but more stack is used.
1608     8. Applied Daniel's patches to solve problems with the import/export magic
1609        syntax that is required for Windows, and which was going wrong for the
1610        pcreposix and pcrecpp parts of the library. These were overlooked when this
1611        problem was solved for the main library.
1613     9. There were some crude static tests to avoid integer overflow when computing
1614        the size of patterns that contain repeated groups with explicit upper
1615        limits. As the maximum quantifier is 65535, the maximum group length was
1616        set at 30,000 so that the product of these two numbers did not overflow a
1617        32-bit integer. However, it turns out that people want to use groups that
1618        are longer than 30,000 bytes (though not repeat them that many times).
1619        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1620        made it possible to implement the integer overflow checks in a much more
1621        dynamic way, which I have now done. The artificial limitation on group
1622        length has been removed - we now have only the limit on the total length of
1623        the compiled pattern, which depends on the LINK_SIZE setting.
1625    10. Fixed a bug in the documentation for get/copy named substring when
1626        duplicate names are permitted. If none of the named substrings are set, the
1627        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1628        empty string.
1630    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1631        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1632        because the ] is interpreted as the first data character and the
1633        terminating ] is not found. PCRE has been made compatible with Perl in this
1634        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1635        cause memory overwriting.
1637    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1638        string has been matched (to stop an infinite loop). It was not recognizing
1639        a conditional subpattern that could match an empty string if that
1640        subpattern was within another subpattern. For example, it looped when
1641        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1642        condition was not nested. This bug has been fixed.
1644    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1645        past the start of the subject in the presence of bytes with the top bit
1646        set, for example "\x8aBCD".
1648    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1649        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1651    14. Optimized (?!) to (*FAIL).
1653    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1654        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1655        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1656        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1657        does: it's just the validity check that is more restrictive.
1659    16. Inserted checks for integer overflows during escape sequence (backslash)
1660        processing, and also fixed erroneous offset values for syntax errors during
1661        backslash processing.
1663    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1664        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1666    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1667        caused an overrun.
1669    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1670        something other than just ASCII characters) inside a group that had an
1671        unlimited repeat caused a loop at compile time (while checking to see
1672        whether the group could match an empty string).
1674    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1675        [\P{Any}] did so. (Error in the code for printing property names.)
1677    21. An orphan \E inside a character class could cause a crash.
1679    22. A repeated capturing bracket such as (A)? could cause a wild memory
1680        reference during compilation.
1682    23. There are several functions in pcre_compile() that scan along a compiled
1683        expression for various reasons (e.g. to see if it's fixed length for look
1684        behind). There were bugs in these functions when a repeated \p or \P was
1685        present in the pattern. These operators have additional parameters compared
1686        with \d, etc, and these were not being taken into account when moving along
1687        the compiled data. Specifically:
1689        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1690            length.
1692        (b) An item such as \pL+ within a repeated group could cause crashes or
1693            loops.
1695        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1696            "reference to non-existent subpattern" error.
1698        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1700    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1701        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1703    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1705    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1706        character were causing crashes (broken optimization).
1708    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1709        \p or \P) caused a compile-time loop.
1711    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1712        break. For example, the unstudied pattern [\r\n]A does not match the string
1713        "\r\nA" because change 7.0/46 below moves the current point on by two
1714        characters after failing to match at the start. However, the pattern \nA
1715        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1716        the same is true. There doesn't seem any very clean way out of this, but
1717        what I have chosen to do makes the common cases work: PCRE now takes note
1718        of whether there can be an explicit match for \r or \n anywhere in the
1719        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1720        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1721        pattern has explicit CR or LF references.
1723    29. Added (*CR) etc for changing newline setting at start of pattern.
1726    Version 7.2 19-Jun-07
1727    ---------------------
1729     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1730        which is apparently normally available under Windows.
1732     2. Re-jig the pcregrep tests with different newline settings in an attempt
1733        to make them independent of the local environment's newline setting.
1735     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1737     4. Some of the "internals" tests were previously cut out when the link size
1738        was not 2, because the output contained actual offsets. The recent new
1739        "Z" feature of pcretest means that these can be cut out, making the tests
1740        usable with all link sizes.
1742     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1743        stack recursion. This gives a massive performance boost under BSD, but just
1744        a small improvement under Linux. However, it saves one field in the frame
1745        in all cases.
1747     6. Added more features from the forthcoming Perl 5.10:
1749        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1750            recursion call. It refers to the nth most recently opened parentheses.
1752        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1753            to be opened parentheses.
1755        (c) Conditions that refer to capturing parentheses can be specified
1756            relatively, for example, (?(-2)... or (?(+3)...
1758        (d) \K resets the start of the current match so that everything before
1759            is not part of it.
1761        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1763        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1764            reference syntax.
1766        (g) (?| introduces a group in which the numbering of parentheses in each
1767            alternative starts with the same number.
1769        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1771     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1774     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1775        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1776        for detecting groups that can match an empty string.
1778     9. A pattern with a very large number of alternatives (more than several
1779        hundred) was running out of internal workspace during the pre-compile
1780        phase, where pcre_compile() figures out how much memory will be needed. A
1781        bit of new cunning has reduced the workspace needed for groups with
1782        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1783        workspace instead of running out of the 4096 that are available.
1785    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1787    11. Applied patch from Google to remove an optimization that didn't quite work.
1788        The report of the bug said:
1790          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1791          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1792          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1794    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1795        it matched the wrong number of bytes.
1798    Version 7.1 24-Apr-07
1799  ---------------------  ---------------------
1801   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 142  Version 7.1 12-Mar-07 Line 1936  Version 7.1 12-Mar-07
1937  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1938      CRLF as a newline sequence.      CRLF as a newline sequence.
1940  22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut  22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1941      out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but      out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1942      I have nevertheless tidied it up.      I have nevertheless tidied it up.
1944  23. Added some casts to kill warnings from HP-UX ia64 compiler.  23. Added some casts to kill warnings from HP-UX ia64 compiler.
1946    24. Added a man page for pcre-config.
1949  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06

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