/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 189 by ph10, Thu Jul 5 11:50:49 2007 UTC revision 687 by ph10, Tue Sep 6 16:09:43 2011 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-07  Version 8.20
5    ------------
6    
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8       a POSIX class. After further experiments with Perl, which convinced me that
9       Perl has bugs and confusions, a closing square bracket is no longer allowed
10       in a POSIX name.
11    
12    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
13       substring, but while checking the failing first alternative, substring 1 is
14       temporarily captured. If the output vector supplied to pcre_exec() was not
15       big enough for this capture, the yield of the function was still zero
16       ("insufficient space for captured substrings"). This cannot be totally fixed
17       without adding another stack variable, which seems a lot of expense for a
18       edge case. However, I have improved the situation in cases such as
19       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
20       fewer than the maximum number of slots in the ovector have been set.
21    
22    3. Related to (2) above: when there are more back references in a pattern than
23       slots in the output vector, pcre_exec() uses temporary memory during
24       matching, and copies in the captures as far as possible afterwards. It was
25       using the entire output vector, but this conflicts with the specification
26       that only 2/3 is used for passing back captured substrings. Now it uses only
27       the first 2/3, for compatibility. This is, of course, another edge case.
28    
29    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
30       main code base, and can be used by building with --enable-jit. When this is
31       done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
32       runtime --no-jit option is given.
33    
34    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
35       ovector, the return from the function was zero, implying that there were
36       other matches that did not fit. The correct "exactly full" value is now
37       returned.
38    
39    6. If a subpattern that was called recursively or as a subroutine contained
40       (*PRUNE) or any other control that caused it to give a non-standard return,
41       invalid errors such as "Error -26 (nested recursion at the same subject
42       position)" or even infinite loops could occur.
43    
44    
45    Version 8.13 16-Aug-2011
46    ------------------------
47    
48    1.  The Unicode data tables have been updated to Unicode 6.0.0.
49    
50    2.  Two minor typos in pcre_internal.h have been fixed.
51    
52    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
53        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
54        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
55    
56    4.  There were a number of related bugs in the code for matching backrefences
57        caselessly in UTF-8 mode when codes for the characters concerned were
58        different numbers of bytes. For example, U+023A and U+2C65 are an upper
59        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
60        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
61        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
62        2-byte code at the end of the subject (it thought there wasn't enough data
63        left).
64    
65    5.  Comprehensive information about what went wrong is now returned by
66        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
67        as the output vector has at least 2 elements. The offset of the start of
68        the failing character and a reason code are placed in the vector.
69    
70    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
71        now returned is for the first byte of the failing character, instead of the
72        last byte inspected. This is an incompatible change, but I hope it is small
73        enough not to be a problem. It makes the returned offset consistent with
74        pcre_exec() and pcre_dfa_exec().
75    
76    7.  pcretest now gives a text phrase as well as the error number when
77        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
78        failure, the offset and reason code are output.
79    
80    8.  When \R was used with a maximizing quantifier it failed to skip backwards
81        over a \r\n pair if the subsequent match failed. Instead, it just skipped
82        back over a single character (\n). This seems wrong (because it treated the
83        two characters as a single entity when going forwards), conflicts with the
84        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
85        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
86        has been changed.
87    
88    9.  Some internal refactoring has changed the processing so that the handling
89        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
90        time (the PCRE_DOTALL option was changed this way some time ago: version
91        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
92        which was always a bit of a fudge. It also means that there is one less
93        argument for the match() function, which reduces its stack requirements
94        slightly. This change also fixes an incompatibility with Perl: the pattern
95        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
96    
97    10. More internal refactoring has drastically reduced the number of recursive
98        calls to match() for possessively repeated groups such as (abc)++ when
99        using pcre_exec().
100    
101    11. While implementing 10, a number of bugs in the handling of groups were
102        discovered and fixed:
103    
104        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
105        (a|)*(?1) gave a compile-time internal error.
106        ((a|)+)+  did not notice that the outer group could match an empty string.
107        (^a|^)+   was not marked as anchored.
108        (.*a|.*)+ was not marked as matching at start or after a newline.
109    
110    12. Yet more internal refactoring has removed another argument from the match()
111        function. Special calls to this function are now indicated by setting a
112        value in a variable in the "match data" data block.
113    
114    13. Be more explicit in pcre_study() instead of relying on "default" for
115        opcodes that mean there is no starting character; this means that when new
116        ones are added and accidentally left out of pcre_study(), testing should
117        pick them up.
118    
119    14. The -s option of pcretest has been documented for ages as being an old
120        synonym of -m (show memory usage). I have changed it to mean "force study
121        for every regex", that is, assume /S for every regex. This is similar to -i
122        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
123        using it. It makes it easier to run collections of tests with and without
124        study enabled, and thereby test pcre_study() more easily. All the standard
125        tests are now run with and without -s (but some patterns can be marked as
126        "never study" - see 20 below).
127    
128    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
129        restoration of the capturing data to the outer values was not happening
130        correctly.
131    
132    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
133        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
134        pattern had matched an empty string, and so incorrectly returned a no
135        match.
136    
137    17. There was optimizing code for the last branch of non-capturing parentheses,
138        and also for the obeyed branch of a conditional subexpression, which used
139        tail recursion to cut down on stack usage. Unfortunately, now that there is
140        the possibility of (*THEN) occurring in these branches, tail recursion is
141        no longer possible because the return has to be checked for (*THEN). These
142        two optimizations have therefore been removed.
143    
144    18. If a pattern containing \R was studied, it was assumed that \R always
145        matched two bytes, thus causing the minimum subject length to be
146        incorrectly computed because \R can also match just one byte.
147    
148    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
149        was incorrectly computed.
150    
151    20. If /S is present twice on a test pattern in pcretest input, it now
152        *disables* studying, thereby overriding the use of -s on the command line
153        (see 14 above). This is necessary for one or two tests to keep the output
154        identical in both cases.
155    
156    21. When (*ACCEPT) was used in an assertion that matched an empty string and
157        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
158    
159    22. When an atomic group that contained a capturing parenthesis was
160        successfully matched, but the branch in which it appeared failed, the
161        capturing was not being forgotten if a higher numbered group was later
162        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
163        group 1 to "a", when in fact it should be unset. This applied to multi-
164        branched capturing and non-capturing groups, repeated or not, and also to
165        positive assertions (capturing in negative assertions does not happen
166        in PCRE) and also to nested atomic groups.
167    
168    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
169        subject after a captured substring, to make it easier to tell which of a
170        number of identical substrings has been captured.
171    
172    24. The way atomic groups are processed by pcre_exec() has been changed so that
173        if they are repeated, backtracking one repetition now resets captured
174        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
175        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
176        "aaa". Previously, it would have been "a". As part of this code
177        refactoring, the way recursive calls are handled has also been changed.
178    
179    25. If an assertion condition captured any substrings, they were not passed
180        back unless some other capturing happened later. For example, if
181        (?(?=(a))a) was matched against "a", no capturing was returned.
182    
183    26. When studying a pattern that contained subroutine calls or assertions,
184        the code for finding the minimum length of a possible match was handling
185        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
186        group 1 called group 2 while simultaneously a separate group 2 called group
187        1). A stack overflow occurred in this case. I have fixed this by limiting
188        the recursion depth to 10.
189    
190    27. Updated RunTest.bat in the distribution to the version supplied by Tom
191        Fortmann. This supports explicit test numbers on the command line, and has
192        argument validation and error reporting.
193    
194    28. An instance of \X with an unlimited repeat could fail if at any point the
195        first character it looked at was a mark character.
196    
197    29. Some minor code refactoring concerning Unicode properties and scripts
198        should reduce the stack requirement of match() slightly.
199    
200    30. Added the '=' option to pcretest to check the setting of unused capturing
201        slots at the end of the pattern, which are documented as being -1, but are
202        not included in the return count.
203    
204    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
205        compiled something random. Now it gives a compile-time error (as does
206        Perl).
207    
208    32. A *MARK encountered during the processing of a positive assertion is now
209        recorded and passed back (compatible with Perl).
210    
211    33. If --only-matching or --colour was set on a pcregrep call whose pattern
212        had alternative anchored branches, the search for a second match in a line
213        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
214        matched the line "0102" twice. The same bug affected patterns that started
215        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
216        twice.
217    
218    34. Previously, PCRE did not allow quantification of assertions. However, Perl
219        does, and because of capturing effects, quantifying parenthesized
220        assertions may at times be useful. Quantifiers are now allowed for
221        parenthesized assertions.
222    
223    35. A minor code tidy in pcre_compile() when checking options for \R usage.
224    
225    36. \g was being checked for fancy things in a character class, when it should
226        just be a literal "g".
227    
228    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
229        appearance of a nested POSIX class supersedes an apparent external class.
230        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
231        unescaped square brackets may also appear as part of class names. For
232        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
233        more like Perl. (But see 8.20/1 above.)
234    
235    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
236        was because it thought it was \N{name}, which is not supported).
237    
238    39. Add minix to OS list not supporting the -S option in pcretest.
239    
240    40. PCRE tries to detect cases of infinite recursion at compile time, but it
241        cannot analyze patterns in sufficient detail to catch mutual recursions
242        such as ((?1))((?2)). There is now a runtime test that gives an error if a
243        subgroup is called recursively as a subpattern for a second time at the
244        same position in the subject string. In previous releases this might have
245        been caught by the recursion limit, or it might have run out of stack.
246    
247    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
248        happen only once. PCRE was, however incorrectly giving a compile time error
249        "recursive call could loop indefinitely" because it cannot analyze the
250        pattern in sufficient detail. The compile time test no longer happens when
251        PCRE is compiling a conditional subpattern, but actual runaway loops are
252        now caught at runtime (see 40 above).
253    
254    42. It seems that Perl allows any characters other than a closing parenthesis
255        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
256        has been changed to be the same.
257    
258    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
259        as not to get warnings when autogen.sh is called. Also changed
260        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
261    
262    44. To help people who use pcregrep to scan files containing exceedingly long
263        lines, the following changes have been made:
264    
265        (a) The default value of the buffer size parameter has been increased from
266            8K to 20K. (The actual buffer used is three times this size.)
267    
268        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
269            PCRE is built.
270    
271        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
272            to be set at run time.
273    
274        (d) Numerical values in pcregrep options can be followed by K or M, for
275            example --buffer-size=50K.
276    
277        (e) If a line being scanned overflows pcregrep's buffer, an error is now
278            given and the return code is set to 2.
279    
280    45. Add a pointer to the latest mark to the callout data block.
281    
282    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
283        partial match of an empty string instead of no match. This was specific to
284        the use of ".".
285    
286    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
287        complete match instead of a partial match. This bug was dependent on both
288        the PCRE_UTF8 and PCRE_DOTALL options being set.
289    
290    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
291        starting byte set, because \b was not being ignored.
292    
293    
294    Version 8.12 15-Jan-2011
295    ------------------------
296    
297    1.  Fixed some typos in the markup of the man pages, and wrote a script that
298        checks for such things as part of the documentation building process.
299    
300    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
301        --match-limit and --recursion-limit options (added for 8.11). In
302        particular, this made one of the standard tests fail. (The integer value
303        went into the wrong half of a long int.)
304    
305    3.  If the --colour option was given to pcregrep with -v (invert match), it
306        did strange things, either producing crazy output, or crashing. It should,
307        of course, ignore a request for colour when reporting lines that do not
308        match.
309    
310    4.  Another pcregrep bug caused similar problems if --colour was specified with
311        -M (multiline) and the pattern match finished with a line ending.
312    
313    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
314        matched in multiline mode, the following line was shown as part of the
315        match. This seems wrong, so I have changed it.
316    
317    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
318        the check for further matches in the same line (so they could be coloured)
319        to overrun the end of the current line. If another match was found, it was
320        incorrectly shown (and then shown again when found in the next line).
321    
322    7.  If pcregrep was compiled under Windows, there was a reference to the
323        function pcregrep_exit() before it was defined. I am assuming this was
324        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
325        reported by a user. I've moved the definition above the reference.
326    
327    
328    Version 8.11 10-Dec-2010
329    ------------------------
330    
331    1.  (*THEN) was not working properly if there were untried alternatives prior
332        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
333        backtracked to try for "b" instead of moving to the next alternative branch
334        at the same level (in this case, to look for "c"). The Perl documentation
335        is clear that when (*THEN) is backtracked onto, it goes to the "next
336        alternative in the innermost enclosing group".
337    
338    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
339        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
340        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
341        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
342        (*THEN).
343    
344    3.  If \s appeared in a character class, it removed the VT character from
345        the class, even if it had been included by some previous item, for example
346        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
347        of \s, but is part of the POSIX "space" class.)
348    
349    4.  A partial match never returns an empty string (because you can always
350        match an empty string at the end of the subject); however the checking for
351        an empty string was starting at the "start of match" point. This has been
352        changed to the "earliest inspected character" point, because the returned
353        data for a partial match starts at this character. This means that, for
354        example, /(?<=abc)def/ gives a partial match for the subject "abc"
355        (previously it gave "no match").
356    
357    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
358        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
359        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
360        has an implication that the given string is incomplete (because a partial
361        match is preferred over a full match). For this reason, these items now
362        give a partial match in this situation. [Aside: previously, the one case
363        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
364        match rather than a full match, which was wrong by the old rules, but is
365        now correct.]
366    
367    6.  There was a bug in the handling of #-introduced comments, recognized when
368        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
369        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
370        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
371        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
372        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
373        places in pcre_compile().
374    
375    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
376        comments when looking ahead for named forward references to subpatterns,
377        the only newline sequence it recognized was NL. It now handles newlines
378        according to the set newline convention.
379    
380    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
381        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
382        cater for a lack of strerror(). These oversights have been fixed.
383    
384    9.  Added --match-limit and --recursion-limit to pcregrep.
385    
386    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
387    
388    11. When the -o option was used, pcregrep was setting a return code of 1, even
389        when matches were found, and --line-buffered was not being honoured.
390    
391    12. Added an optional parentheses number to the -o and --only-matching options
392        of pcregrep.
393    
394    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
395        can match an empty string. The code to do it in pcretest and pcredemo
396        needed fixing:
397    
398        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
399            only one byte after an empty string match just before CRLF (this case
400            just got forgotten; "any" and "anycrlf" were OK).
401    
402        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
403            mode when an empty string match preceded an ASCII character followed by
404            a non-ASCII character. (The code for advancing by one character rather
405            than one byte was nonsense.)
406    
407        (c) The pcredemo.c sample program did not have any code at all to handle
408            the cases when CRLF is a valid newline sequence.
409    
410    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
411        as a starting offset was within the subject string. There is now a new
412        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
413        negative or greater than the length of the string. In order to test this,
414        pcretest is extended to allow the setting of negative starting offsets.
415    
416    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
417        starting offset points to the beginning of a UTF-8 character was
418        unnecessarily clumsy. I tidied it up.
419    
420    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
421        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
422    
423    17. Nobody had reported that the --include_dir option, which was added in
424        release 7.7 should have been called --include-dir (hyphen, not underscore)
425        for compatibility with GNU grep. I have changed it to --include-dir, but
426        left --include_dir as an undocumented synonym, and the same for
427        --exclude-dir, though that is not available in GNU grep, at least as of
428        release 2.5.4.
429    
430    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
431        characters from a string of bytes) have been redefined so as not to use
432        loops, in order to improve performance in some environments. At the same
433        time, I abstracted some of the common code into auxiliary macros to save
434        repetition (this should not affect the compiled code).
435    
436    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
437        compile-time error is now given if \c is not followed by an ASCII
438        character, that is, a byte less than 128. (In EBCDIC mode, the code is
439        different, and any byte value is allowed.)
440    
441    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
442        START_OPTIMIZE option, which is now allowed at compile time - but just
443        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
444        to pcregrep and other applications that have no direct access to PCRE
445        options. The new /Y option in pcretest sets this option when calling
446        pcre_compile().
447    
448    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
449        back references. Groups containing recursive back references were forced to
450        be atomic by that change, but in the case of named groups, the amount of
451        memory required was incorrectly computed, leading to "Failed: internal
452        error: code overflow". This has been fixed.
453    
454    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
455        pcretest.c, to avoid build problems in some Borland environments.
456    
457    
458    Version 8.10 25-Jun-2010
459    ------------------------
460    
461    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
462        THEN.
463    
464    2.  (*ACCEPT) was not working when inside an atomic group.
465    
466    3.  Inside a character class, \B is treated as a literal by default, but
467        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
468        causes the error). The code is unchanged, but I tidied the documentation.
469    
470    4.  Inside a character class, PCRE always treated \R and \X as literals,
471        whereas Perl faults them if its -w option is set. I have changed PCRE so
472        that it faults them when PCRE_EXTRA is set.
473    
474    5.  Added support for \N, which always matches any character other than
475        newline. (It is the same as "." when PCRE_DOTALL is not set.)
476    
477    6.  When compiling pcregrep with newer versions of gcc which may have
478        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
479        declared with attribute warn_unused_result" were given. Just casting the
480        result to (void) does not stop the warnings; a more elaborate fudge is
481        needed. I've used a macro to implement this.
482    
483    7.  Minor change to pcretest.c to avoid a compiler warning.
484    
485    8.  Added four artifical Unicode properties to help with an option to make
486        \s etc use properties (see next item). The new properties are: Xan
487        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
488    
489    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
490        use Unicode properties. (*UCP) at the start of a pattern can be used to set
491        this option. Modified pcretest to add /W to test this facility. Added
492        REG_UCP to make it available via the POSIX interface.
493    
494    10. Added --line-buffered to pcregrep.
495    
496    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
497        studied, and the match started with a letter with a code point greater than
498        127 whose first byte was different to the first byte of the other case of
499        the letter, the other case of this starting letter was not recognized
500        (#976).
501    
502    12. If a pattern that was studied started with a repeated Unicode property
503        test, for example, \p{Nd}+, there was the theoretical possibility of
504        setting up an incorrect bitmap of starting bytes, but fortunately it could
505        not have actually happened in practice until change 8 above was made (it
506        added property types that matched character-matching opcodes).
507    
508    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
509        possible starting bytes for non-anchored patterns.
510    
511    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
512        \R, and also a number of cases that involve Unicode properties, both
513        explicit and implicit when PCRE_UCP is set.
514    
515    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
516        input, it could crash or give wrong results if characters with values
517        greater than 0xc0 were present in the subject string. (Detail: it assumed
518        UTF-8 input when processing these items.)
519    
520    16. Added a lot of (int) casts to avoid compiler warnings in systems where
521        size_t is 64-bit (#991).
522    
523    17. Added a check for running out of memory when PCRE is compiled with
524        --disable-stack-for-recursion (#990).
525    
526    18. If the last data line in a file for pcretest does not have a newline on
527        the end, a newline was missing in the output.
528    
529    19. The default pcre_chartables.c file recognizes only ASCII characters (values
530        less than 128) in its various bitmaps. However, there is a facility for
531        generating tables according to the current locale when PCRE is compiled. It
532        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
533        characters, are recognized by isspace() and therefore were getting set in
534        these tables, and indeed these tables seem to approximate to ISO 8859. This
535        caused a problem in UTF-8 mode when pcre_study() was used to create a list
536        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
537        which of course cannot start UTF-8 characters. I have changed the code so
538        that only real ASCII characters (less than 128) and the correct starting
539        bytes for UTF-8 encodings are set for characters greater than 127 when in
540        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
541        altogether.)
542    
543    20. Added the /T option to pcretest so as to be able to run tests with non-
544        standard character tables, thus making it possible to include the tests
545        used for 19 above in the standard set of tests.
546    
547    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
548        reference to a subpattern the other side of a comment that contains an
549        opening parenthesis caused either an internal compiling error, or a
550        reference to the wrong subpattern.
551    
552    
553    Version 8.02 19-Mar-2010
554    ------------------------
555    
556    1.  The Unicode data tables have been updated to Unicode 5.2.0.
557    
558    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
559        configured.
560    
561    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
562        original author of that file, following a query about its status.
563    
564    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
565        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
566    
567    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
568        quantifier applied to a forward-referencing subroutine call, could compile
569        incorrect code or give the error "internal error: previously-checked
570        referenced subpattern not found".
571    
572    6.  Both MS Visual Studio and Symbian OS have problems with initializing
573        variables to point to external functions. For these systems, therefore,
574        pcre_malloc etc. are now initialized to local functions that call the
575        relevant global functions.
576    
577    7.  There were two entries missing in the vectors called coptable and poptable
578        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
579        I've fixed the data, and added a kludgy way of testing at compile time that
580        the lengths are correct (equal to the number of opcodes).
581    
582    8.  Following on from 7, I added a similar kludge to check the length of the
583        eint vector in pcreposix.c.
584    
585    9.  Error texts for pcre_compile() are held as one long string to avoid too
586        much relocation at load time. To find a text, the string is searched,
587        counting zeros. There was no check for running off the end of the string,
588        which could happen if a new error number was added without updating the
589        string.
590    
591    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
592    
593    11. \K was not working if it appeared in an atomic group or in a group that
594        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
595        \K is "not well defined" if used in an assertion. PCRE now accepts it if
596        the assertion is positive, but not if it is negative.
597    
598    12. Change 11 fortuitously reduced the size of the stack frame used in the
599        "match()" function of pcre_exec.c by one pointer. Forthcoming
600        implementation of support for (*MARK) will need an extra pointer on the
601        stack; I have reserved it now, so that the stack frame size does not
602        decrease.
603    
604    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
605        item in branch that calls a recursion is a subroutine call - as in the
606        second branch in the above example - was incorrectly given the compile-
607        time error "recursive call could loop indefinitely" because pcre_compile()
608        was not correctly checking the subroutine for matching a non-empty string.
609    
610    14. The checks for overrunning compiling workspace could trigger after an
611        overrun had occurred. This is a "should never occur" error, but it can be
612        triggered by pathological patterns such as hundreds of nested parentheses.
613        The checks now trigger 100 bytes before the end of the workspace.
614    
615    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
616    
617    
618    Version 8.01 19-Jan-2010
619    ------------------------
620    
621    1.  If a pattern contained a conditional subpattern with only one branch (in
622        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
623        computed the wrong minimum data length (which is of course zero for such
624        subpatterns). This could cause incorrect "no match" results.
625    
626    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
627        the pattern is reset in the first branch, pcre_compile() failed with
628        "internal error: code overflow at offset...". This happened only when
629        the reset was to the original external option setting. (An optimization
630        abstracts leading options settings into an external setting, which was the
631        cause of this.)
632    
633    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
634        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
635        assertion pattern did not match (meaning that the assertion was true), it
636        was incorrectly treated as false if the SKIP had been reached during the
637        matching. This also applied to assertions used as conditions.
638    
639    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
640        assertion subpattern, including such a pattern used as a condition,
641        unpredictable results occurred, instead of the error return
642        PCRE_ERROR_DFA_UITEM.
643    
644    5.  The C++ GlobalReplace function was not working like Perl for the special
645        situation when an empty string is matched. It now does the fancy magic
646        stuff that is necessary.
647    
648    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
649        removed. (These were left over from very, very early versions of PCRE.)
650    
651    7.  Some cosmetic changes to the code to make life easier when compiling it
652        as part of something else:
653    
654        (a) Change DEBUG to PCRE_DEBUG.
655    
656        (b) In pcre_compile(), rename the member of the "branch_chain" structure
657            called "current" as "current_branch", to prevent a collision with the
658            Linux macro when compiled as a kernel module.
659    
660        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
661            prevent a collision with the Linux macro when compiled as a kernel
662            module.
663    
664    8.  In pcre_compile() there are some checks for integer overflows that used to
665        cast potentially large values to (double). This has been changed to that
666        when building, a check for int64_t is made, and if it is found, it is used
667        instead, thus avoiding the use of floating point arithmetic. (There is no
668        other use of FP in PCRE.) If int64_t is not found, the fallback is to
669        double.
670    
671    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
672        2005 (difference between two addresses compared to an unsigned value).
673    
674    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
675        custom one, because of the following reported problem in Windows:
676    
677          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
678              under Win32.
679          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
680              therefore missing the function definition.
681          - The compiler thus generates a "C" signature for the test function.
682          - The linker fails to find the "C" function.
683          - PCRE fails to configure if asked to do so against libbz2.
684    
685    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
686        messages were output:
687    
688          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
689          rerunning libtoolize, to keep the correct libtool macros in-tree.
690          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
691    
692        I have done both of these things.
693    
694    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
695        most of the time, it *can* run out if it is given a pattern that contains a
696        runaway infinite recursion. I updated the discussion in the pcrestack man
697        page.
698    
699    13. Now that we have gone to the x.xx style of version numbers, the minor
700        version may start with zero. Using 08 or 09 is a bad idea because users
701        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
702        interpreted as invalid octal numbers. I've updated the previous comment in
703        configure.ac, and also added a check that gives an error if 08 or 09 are
704        used.
705    
706    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
707        causing partial matching to fail when the end of the subject matched \W
708        in a UTF-8 pattern where \W was quantified with a minimum of 3.
709    
710    15. There were some discrepancies between the declarations in pcre_internal.h
711        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
712        their definitions. The declarations used "const uschar *" and the
713        definitions used USPTR. Even though USPTR is normally defined as "const
714        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
715        reported that: "This difference in casting confuses some C++ compilers, for
716        example, SunCC recognizes above declarations as different functions and
717        generates broken code for hbpcre." I have changed the declarations to use
718        USPTR.
719    
720    16. GNU libtool is named differently on some systems. The autogen.sh script now
721        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
722        (FreeBSD).
723    
724    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
725        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
726        comment: "Figure out how to create a longlong from a string: strtoll and
727        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
728        instance, but it only takes 2 args instead of 3!"
729    
730    18. A subtle bug concerned with back references has been fixed by a change of
731        specification, with a corresponding code fix. A pattern such as
732        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
733        refers, was giving matches when it shouldn't. For example, xa=xaaa would
734        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
735        same bug. Such groups have to be quantified to be useful, or contained
736        inside another quantified group. (If there's no repetition, the reference
737        can never match.) The problem arises because, having left the group and
738        moved on to the rest of the pattern, a later failure that backtracks into
739        the group uses the captured value from the final iteration of the group
740        rather than the correct earlier one. I have fixed this in PCRE by forcing
741        any group that contains a reference to itself to be an atomic group; that
742        is, there cannot be any backtracking into it once it has completed. This is
743        similar to recursive and subroutine calls.
744    
745    
746    Version 8.00 19-Oct-09
747    ----------------------
748    
749    1.  The table for translating pcre_compile() error codes into POSIX error codes
750        was out-of-date, and there was no check on the pcre_compile() error code
751        being within the table. This could lead to an OK return being given in
752        error.
753    
754    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
755        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
756        in a Windows environment.
757    
758    3.  The pcregrep --count option prints the count for each file even when it is
759        zero, as does GNU grep. However, pcregrep was also printing all files when
760        --files-with-matches was added. Now, when both options are given, it prints
761        counts only for those files that have at least one match. (GNU grep just
762        prints the file name in this circumstance, but including the count seems
763        more useful - otherwise, why use --count?) Also ensured that the
764        combination -clh just lists non-zero counts, with no names.
765    
766    4.  The long form of the pcregrep -F option was incorrectly implemented as
767        --fixed_strings instead of --fixed-strings. This is an incompatible change,
768        but it seems right to fix it, and I didn't think it was worth preserving
769        the old behaviour.
770    
771    5.  The command line items --regex=pattern and --regexp=pattern were not
772        recognized by pcregrep, which required --regex pattern or --regexp pattern
773        (with a space rather than an '='). The man page documented the '=' forms,
774        which are compatible with GNU grep; these now work.
775    
776    6.  No libpcreposix.pc file was created for pkg-config; there was just
777        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
778    
779    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
780        when UCP support is not needed, by modifying the Python script that
781        generates it from Unicode data files. This should not matter if the module
782        is correctly used as a library, but I received one complaint about 50K of
783        unwanted data. My guess is that the person linked everything into his
784        program rather than using a library. Anyway, it does no harm.
785    
786    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
787        was a minimum greater than 1 for a wide character in a possessive
788        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
789        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
790        character. Chaos in the form of incorrect output or a compiling loop could
791        result.
792    
793    9.  The restrictions on what a pattern can contain when partial matching is
794        requested for pcre_exec() have been removed. All patterns can now be
795        partially matched by this function. In addition, if there are at least two
796        slots in the offset vector, the offset of the earliest inspected character
797        for the match and the offset of the end of the subject are set in them when
798        PCRE_ERROR_PARTIAL is returned.
799    
800    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
801        synonymous with PCRE_PARTIAL, for backwards compatibility, and
802        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
803        and may be more useful for multi-segment matching.
804    
805    11. Partial matching with pcre_exec() is now more intuitive. A partial match
806        used to be given if ever the end of the subject was reached; now it is
807        given only if matching could not proceed because another character was
808        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
809        string "Z", which now yields "no match" instead of "partial match". In the
810        case of pcre_dfa_exec(), "no match" is given if every matching path for the
811        final character ended with (*FAIL).
812    
813    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
814        if the pattern had a "must contain" character that was already found in the
815        earlier partial match, unless partial matching was again requested. For
816        example, with the pattern /dog.(body)?/, the "must contain" character is
817        "g". If the first part-match was for the string "dog", restarting with
818        "sbody" failed. This bug has been fixed.
819    
820    13. The string returned by pcre_dfa_exec() after a partial match has been
821        changed so that it starts at the first inspected character rather than the
822        first character of the match. This makes a difference only if the pattern
823        starts with a lookbehind assertion or \b or \B (\K is not supported by
824        pcre_dfa_exec()). It's an incompatible change, but it makes the two
825        matching functions compatible, and I think it's the right thing to do.
826    
827    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
828        so that the demonstration program is easily available in environments where
829        PCRE has not been installed from source.
830    
831    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
832        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
833        library.
834    
835    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
836        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
837        is not the first non-POSIX option to be added. Clearly some people find
838        these options useful.
839    
840    17. If a caller to the POSIX matching function regexec() passes a non-zero
841        value for nmatch with a NULL value for pmatch, the value of
842        nmatch is forced to zero.
843    
844    18. RunGrepTest did not have a test for the availability of the -u option of
845        the diff command, as RunTest does. It now checks in the same way as
846        RunTest, and also checks for the -b option.
847    
848    19. If an odd number of negated classes containing just a single character
849        interposed, within parentheses, between a forward reference to a named
850        subpattern and the definition of the subpattern, compilation crashed with
851        an internal error, complaining that it could not find the referenced
852        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
853        [The bug was that it was starting one character too far in when skipping
854        over the character class, thus treating the ] as data rather than
855        terminating the class. This meant it could skip too much.]
856    
857    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
858        /g option in pcretest when the pattern contains \K, which makes it possible
859        to have an empty string match not at the start, even when the pattern is
860        anchored. Updated pcretest and pcredemo to use this option.
861    
862    21. If the maximum number of capturing subpatterns in a recursion was greater
863        than the maximum at the outer level, the higher number was returned, but
864        with unset values at the outer level. The correct (outer level) value is
865        now given.
866    
867    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
868        PCRE did not set those parentheses (unlike Perl). I have now found a way to
869        make it do so. The string so far is captured, making this feature
870        compatible with Perl.
871    
872    23. The tests have been re-organized, adding tests 11 and 12, to make it
873        possible to check the Perl 5.10 features against Perl 5.10.
874    
875    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
876        pattern matches a fixed length string. PCRE did not allow this; now it
877        does. Neither allows recursion.
878    
879    25. I finally figured out how to implement a request to provide the minimum
880        length of subject string that was needed in order to match a given pattern.
881        (It was back references and recursion that I had previously got hung up
882        on.) This code has now been added to pcre_study(); it finds a lower bound
883        to the length of subject needed. It is not necessarily the greatest lower
884        bound, but using it to avoid searching strings that are too short does give
885        some useful speed-ups. The value is available to calling programs via
886        pcre_fullinfo().
887    
888    26. While implementing 25, I discovered to my embarrassment that pcretest had
889        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
890        study optimizations had never been tested with that matching function.
891        Oops. What is worse, even when it was passed study data, there was a bug in
892        pcre_dfa_exec() that meant it never actually used it. Double oops. There
893        were also very few tests of studied patterns with pcre_dfa_exec().
894    
895    27. If (?| is used to create subpatterns with duplicate numbers, they are now
896        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
897        on the other side of the coin, they are no longer allowed to have different
898        names, because these cannot be distinguished in PCRE, and this has caused
899        confusion. (This is a difference from Perl.)
900    
901    28. When duplicate subpattern names are present (necessarily with different
902        numbers, as required by 27 above), and a test is made by name in a
903        conditional pattern, either for a subpattern having been matched, or for
904        recursion in such a pattern, all the associated numbered subpatterns are
905        tested, and the overall condition is true if the condition is true for any
906        one of them. This is the way Perl works, and is also more like the way
907        testing by number works.
908    
909    
910    Version 7.9 11-Apr-09
911    ---------------------
912    
913    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
914        (pcretest), all targets were linked against these libraries. This included
915        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
916        libraries. This caused unwanted dependencies to be created. This problem
917        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
918        pcretest is linked with readline.
919    
920    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
921        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
922        moved outside it again, because FALSE and TRUE are already defined in AIX,
923        but BOOL is not.
924    
925    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
926        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
927    
928    4.  The pcregrep documentation said spaces were inserted as well as colons (or
929        hyphens) following file names and line numbers when outputting matching
930        lines. This is not true; no spaces are inserted. I have also clarified the
931        wording for the --colour (or --color) option.
932    
933    5.  In pcregrep, when --colour was used with -o, the list of matching strings
934        was not coloured; this is different to GNU grep, so I have changed it to be
935        the same.
936    
937    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
938        each matching line was coloured. Now it goes on to look for further matches
939        of any of the test patterns, which is the same behaviour as GNU grep.
940    
941    7.  A pattern that could match an empty string could cause pcregrep to loop; it
942        doesn't make sense to accept an empty string match in pcregrep, so I have
943        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
944        seems to be how GNU grep behaves.
945    
946    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
947        start or after a newline", because the conditional assertion was not being
948        correctly handled. The rule now is that both the assertion and what follows
949        in the first alternative must satisfy the test.
950    
951    9.  If auto-callout was enabled in a pattern with a conditional group whose
952        condition was an assertion, PCRE could crash during matching, both with
953        pcre_exec() and pcre_dfa_exec().
954    
955    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
956        used for matching.
957    
958    11. Unicode property support in character classes was not working for
959        characters (bytes) greater than 127 when not in UTF-8 mode.
960    
961    12. Added the -M command line option to pcretest.
962    
963    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
964    
965    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
966    
967    16. Added comments and documentation about mis-use of no_arg in the C++
968        wrapper.
969    
970    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
971        from Martin Jerabek that uses macro names for all relevant character and
972        string constants.
973    
974    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
975        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
976        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
977        these, but not everybody uses configure.
978    
979    19. A conditional group that had only one branch was not being correctly
980        recognized as an item that could match an empty string. This meant that an
981        enclosing group might also not be so recognized, causing infinite looping
982        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
983        with the subject "ab", where knowledge that the repeated group can match
984        nothing is needed in order to break the loop.
985    
986    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
987        exec(), but without supplying a callout function, matching went wrong.
988    
989    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
990        leak if the size of the offset vector was greater than 30. When the vector
991        is smaller, the saved offsets during recursion go onto a local stack
992        vector, but for larger vectors malloc() is used. It was failing to free
993        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
994        error, in fact).
995    
996    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
997        heapframe that is used only when UTF-8 support is enabled. This caused no
998        problem, but was untidy.
999    
1000    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1001        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1002        included within another project.
1003    
1004    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1005        slightly modified by me:
1006    
1007          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1008              not building pcregrep.
1009    
1010          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1011              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1012    
1013    25. Forward references, both numeric and by name, in patterns that made use of
1014        duplicate group numbers, could behave incorrectly or give incorrect errors,
1015        because when scanning forward to find the reference group, PCRE was not
1016        taking into account the duplicate group numbers. A pattern such as
1017        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1018    
1019    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1020        the feature of a custom pointer more persuasive (as requested by a user).
1021    
1022    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1023        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1024        pre-defined.
1025    
1026    28. Added support for (*UTF8) at the start of a pattern.
1027    
1028    29. Arrange for flags added by the "release type" setting in CMake to be shown
1029        in the configuration summary.
1030    
1031    
1032    Version 7.8 05-Sep-08
1033    ---------------------
1034    
1035    1.  Replaced UCP searching code with optimized version as implemented for Ad
1036        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1037        stage table and inline lookup instead of a function, giving speed ups of 2
1038        to 5 times on some simple patterns that I tested. Permission was given to
1039        distribute the MultiStage2.py script that generates the tables (it's not in
1040        the tarball, but is in the Subversion repository).
1041    
1042    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1043        scripts.
1044    
1045    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1046        a group with a zero qualifier. The result of the study could be incorrect,
1047        or the function might crash, depending on the pattern.
1048    
1049    4.  Caseless matching was not working for non-ASCII characters in back
1050        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1051        It now works when Unicode Property Support is available.
1052    
1053    5.  In pcretest, an escape such as \x{de} in the data was always generating
1054        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1055        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1056        truncation.
1057    
1058    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1059    
1060    7.  Added two (int) casts to pcregrep when printing the difference of two
1061        pointers, in case they are 64-bit values.
1062    
1063    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1064        test 2 if it fails.
1065    
1066    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1067        and a #define of that name to empty if it is not externally set. This is to
1068        allow users of MSVC to set it if necessary.
1069    
1070    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1071        the convenience functions in the pcre_get.c source file.
1072    
1073    11. An option change at the start of a pattern that had top-level alternatives
1074        could cause overwriting and/or a crash. This command provoked a crash in
1075        some environments:
1076    
1077          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1078    
1079        This potential security problem was recorded as CVE-2008-2371.
1080    
1081    12. For a pattern where the match had to start at the beginning or immediately
1082        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1083        pcre_dfa_exec() could read past the end of the passed subject if there was
1084        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1085        pcretest so that it places the subject at the end of its malloc-ed buffer.
1086    
1087    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1088        exec() might read past the end of the data buffer in UTF-8 mode.
1089    
1090    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1091        the data contained the byte 0x85 as part of a UTF-8 character within its
1092        first line. This applied both to normal and DFA matching.
1093    
1094    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1095        /^[^d]*?$/8 failed to match "abc".
1096    
1097    16. Added a missing copyright notice to pcrecpp_internal.h.
1098    
1099    17. Make it more clear in the documentation that values returned from
1100        pcre_exec() in ovector are byte offsets, not character counts.
1101    
1102    18. Tidied a few places to stop certain compilers from issuing warnings.
1103    
1104    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1105        supplied by Stefan Weber. I made a further small update for 7.8 because
1106        there is a change of source arrangements: the pcre_searchfuncs.c module is
1107        replaced by pcre_ucd.c.
1108    
1109    
1110    Version 7.7 07-May-08
1111    ---------------------
1112    
1113    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1114        a string to a long long, pretend we don't even have a long long." This is
1115        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1116    
1117    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1118        pre-7.6 versions, which defined a global no_arg variable instead of putting
1119        it in the RE class. (See also #8 below.)
1120    
1121    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1122        Lopes.
1123    
1124    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1125    
1126        (1) The include/exclude patterns were being applied to the whole pathnames
1127            of files, instead of just to the final components.
1128    
1129        (2) If there was more than one level of directory, the subdirectories were
1130            skipped unless they satisfied the include/exclude conditions. This is
1131            inconsistent with GNU grep (and could even be seen as contrary to the
1132            pcregrep specification - which I improved to make it absolutely clear).
1133            The action now is always to scan all levels of directory, and just
1134            apply the include/exclude patterns to regular files.
1135    
1136    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1137        --exclude_dir in the tests to avoid scanning .svn directories.
1138    
1139    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1140        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1141        doesn't support NULs in patterns.
1142    
1143    7.  Added some missing "const"s to declarations of static tables in
1144        pcre_compile.c and pcre_dfa_exec.c.
1145    
1146    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1147        caused by fix #2  above. (Subsequently also a second patch to fix the
1148        first patch. And a third patch - this was a messy problem.)
1149    
1150    9.  Applied Craig's patch to remove the use of push_back().
1151    
1152    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1153        matching function regexec().
1154    
1155    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1156        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1157        references. PCRE supports relative numbers with this syntax (I don't think
1158        Oniguruma does).
1159    
1160    12. Previously, a group with a zero repeat such as (...){0} was completely
1161        omitted from the compiled regex. However, this means that if the group
1162        was called as a subroutine from elsewhere in the pattern, things went wrong
1163        (an internal error was given). Such groups are now left in the compiled
1164        pattern, with a new opcode that causes them to be skipped at execution
1165        time.
1166    
1167    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1168        to the way PCRE behaves:
1169    
1170        (a) A lone ] character is dis-allowed (Perl treats it as data).
1171    
1172        (b) A back reference to an unmatched subpattern matches an empty string
1173            (Perl fails the current match path).
1174    
1175        (c) A data ] in a character class must be notated as \] because if the
1176            first data character in a class is ], it defines an empty class. (In
1177            Perl it is not possible to have an empty class.) The empty class []
1178            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1179            The negative empty class [^] matches any one character, independently
1180            of the DOTALL setting.
1181    
1182    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1183        non-existent subpattern following a character class starting with ']' and
1184        containing () gave an internal compiling error instead of "reference to
1185        non-existent subpattern". Fortunately, when the pattern did exist, the
1186        compiled code was correct. (When scanning forwards to check for the
1187        existencd of the subpattern, it was treating the data ']' as terminating
1188        the class, so got the count wrong. When actually compiling, the reference
1189        was subsequently set up correctly.)
1190    
1191    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1192        it was being rejected as not supported by pcre_dfa_exec(), even though
1193        other assertions are supported. I have made pcre_dfa_exec() support
1194        (*FAIL).
1195    
1196    16. The implementation of 13c above involved the invention of a new opcode,
1197        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1198        cannot be changed at match time, I realized I could make a small
1199        improvement to matching performance by compiling OP_ALLANY instead of
1200        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1201        on the OP_ANY path.
1202    
1203    17. Compiling pcretest on Windows with readline support failed without the
1204        following two fixes: (1) Make the unistd.h include conditional on
1205        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1206    
1207    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1208        ncurses library to be included for pcretest when ReadLine support is
1209        requested, but also to allow for it to be overridden. This patch came from
1210        Daniel Bergström.
1211    
1212    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1213        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1214        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1215        spotting this.
1216    
1217    
1218    Version 7.6 28-Jan-08
1219    ---------------------
1220    
1221    1.  A character class containing a very large number of characters with
1222        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1223        overflow.
1224    
1225    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1226        HAVE_LONG_LONG is not defined.
1227    
1228    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1229        bring them up to date and include new features. This patch includes:
1230    
1231        - Fixed PH's badly added libz and libbz2 support.
1232        - Fixed a problem with static linking.
1233        - Added pcredemo. [But later removed - see 7 below.]
1234        - Fixed dftables problem and added an option.
1235        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1236            HAVE_LONG_LONG.
1237        - Added readline support for pcretest.
1238        - Added an listing of the option settings after cmake has run.
1239    
1240    4.  A user submitted a patch to Makefile that makes it easy to create
1241        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1242        Makefile.am that cause it to include this special target, without
1243        affecting anything else. Note that the same mingw target plus all
1244        the other distribution libraries and programs are now supported
1245        when configuring with CMake (see 6 below) instead of with
1246        Configure/Make.
1247    
1248    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1249        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1250        exported in the Windows port". It has not yet been confirmed that the patch
1251        solves the problem, but it does no harm.
1252    
1253    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1254        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1255        with CMake, and also correct the comment about stack recursion.
1256    
1257    7.  Remove the automatic building of pcredemo from the ./configure system and
1258        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1259        of a program that users should build themselves after PCRE is installed, so
1260        building it automatically is not really right. What is more, it gave
1261        trouble in some build environments.
1262    
1263    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1264    
1265    
1266    Version 7.5 10-Jan-08
1267    ---------------------
1268    
1269    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1270        values in parens when parsing an RE using the C++ wrapper."
1271    
1272    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1273        Characters greater than 255 were excluded from the class instead of being
1274        included.
1275    
1276    3.  The same bug as (2) above applied to negated POSIX classes such as
1277        [:^space:].
1278    
1279    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1280        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1281        I have changed it.
1282    
1283    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1284        first named subpattern) and a construct such as (?&a) would reference the
1285        first named subpattern whose name started with "a" (in other words, the
1286        length check was missing). Both these problems are fixed. "Subpattern name
1287        expected" is now given for (?&) (a zero-length name), and this patch also
1288        makes it give the same error for \k'' (previously it complained that that
1289        was a reference to a non-existent subpattern).
1290    
1291    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1292        this is right because (?- can be followed by option settings as well as by
1293        digits. I have, however, made the messages clearer.
1294    
1295    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1296        than the number used in the conditional) now cause a compile-time error.
1297        This is actually not compatible with Perl, which accepts such patterns, but
1298        treats the conditional as always being FALSE (as PCRE used to), but it
1299        seems to me that giving a diagnostic is better.
1300    
1301    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1302        and messages.
1303    
1304    9.  Fix two occurrences of "backslash" in comments that should have been
1305        "backspace".
1306    
1307    10. Remove two redundant lines of code that can never be obeyed (their function
1308        was moved elsewhere).
1309    
1310    11. The program that makes PCRE's Unicode character property table had a bug
1311        which caused it to generate incorrect table entries for sequences of
1312        characters that have the same character type, but are in different scripts.
1313        It amalgamated them into a single range, with the script of the first of
1314        them. In other words, some characters were in the wrong script. There were
1315        thirteen such cases, affecting characters in the following ranges:
1316    
1317          U+002b0 - U+002c1
1318          U+0060c - U+0060d
1319          U+0061e - U+00612
1320          U+0064b - U+0065e
1321          U+0074d - U+0076d
1322          U+01800 - U+01805
1323          U+01d00 - U+01d77
1324          U+01d9b - U+01dbf
1325          U+0200b - U+0200f
1326          U+030fc - U+030fe
1327          U+03260 - U+0327f
1328          U+0fb46 - U+0fbb1
1329          U+10450 - U+1049d
1330    
1331    12. The -o option (show only the matching part of a line) for pcregrep was not
1332        compatible with GNU grep in that, if there was more than one match in a
1333        line, it showed only the first of them. It now behaves in the same way as
1334        GNU grep.
1335    
1336    13. If the -o and -v options were combined for pcregrep, it printed a blank
1337        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1338        does the same. The return code can be used to tell if there were any
1339        non-matching lines.
1340    
1341    14. Added --file-offsets and --line-offsets to pcregrep.
1342    
1343    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1344        infinitely looping recursion. The bug was that positive lookaheads were not
1345        being skipped when checking for a possible empty match (negative lookaheads
1346        and both kinds of lookbehind were skipped).
1347    
1348    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1349        inclusion of <windows.h> to before rather than after the definition of
1350        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1351    
1352    17. Specifying a possessive quantifier with a specific limit for a Unicode
1353        character property caused pcre_compile() to compile bad code, which led at
1354        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1355        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1356        caused the error; without that there was no problem.
1357    
1358    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1359    
1360    19. Added --enable-pcretest-libreadline.
1361    
1362    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1363        RE::GlobalReplace(). As a result, the number of replacements returned was
1364        double what it should be. I removed one of the increments, but Craig sent a
1365        later patch that removed the other one (the right fix) and added unit tests
1366        that check the return values (which was not done before).
1367    
1368    21. Several CMake things:
1369    
1370        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1371            the names libpcre and libpcreposix, not just pcre and pcreposix.
1372    
1373        (2) The above change means that pcretest and pcregrep are now correctly
1374            linked with the newly-built libraries, not previously installed ones.
1375    
1376        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1377    
1378    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1379        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1380        UTF-8 newline character). The key issue is that the pattern starts .*;
1381        this means that the match must be either at the beginning, or after a
1382        newline. The bug was in the code for advancing after a failed match and
1383        checking that the new position followed a newline. It was not taking
1384        account of UTF-8 characters correctly.
1385    
1386    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1387        character classes. PCRE was not treating the sequence [:...:] as a
1388        character class unless the ... were all letters. Perl, however, seems to
1389        allow any characters between [: and :], though of course it rejects as
1390        unknown any "names" that contain non-letters, because all the known class
1391        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1392        for example, whereas PCRE did not - it did not recognize a POSIX character
1393        class. This seemed a bit dangerous, so the code has been changed to be
1394        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1395        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1396        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1397        Perl does, and where it didn't before.
1398    
1399    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1400        Windows environments %n is disabled by default.
1401    
1402    
1403    Version 7.4 21-Sep-07
1404    ---------------------
1405    
1406    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1407        means that a class such as [\s] counted as "explicit reference to CR or
1408        LF". That isn't really right - the whole point of the change was to try to
1409        help when there was an actual mention of one of the two characters. So now
1410        the change happens only if \r or \n (or a literal CR or LF) character is
1411        encountered.
1412    
1413    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1414        of both had grown to the point where there were only 3 bits left.
1415        Fortunately, there was spare space in the data structure, and so I have
1416        moved the internal flags into a new 16-bit field to free up more option
1417        bits.
1418    
1419    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1420        but did not set the internal JCHANGED flag - either of these is enough to
1421        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1422        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1423        start sets both bits.
1424    
1425    4.  Added options (at build time, compile time, exec time) to change \R from
1426        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1427    
1428    5.  doc/pcresyntax.html was missing from the distribution.
1429    
1430    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1431        compatibility, even though it is no longer used.
1432    
1433    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1434        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1435        windows.h file is present (where different names are used). [This was
1436        reversed later after testing - see 16 below.]
1437    
1438    8.  Changed all #include <config.h> to #include "config.h". There were also
1439        some further <pcre.h> cases that I changed to "pcre.h".
1440    
1441    9.  When pcregrep was used with the --colour option, it missed the line ending
1442        sequence off the lines that it output.
1443    
1444    10. It was pointed out to me that arrays of string pointers cause lots of
1445        relocations when a shared library is dynamically loaded. A technique of
1446        using a single long string with a table of offsets can drastically reduce
1447        these. I have refactored PCRE in four places to do this. The result is
1448        dramatic:
1449    
1450          Originally:                          290
1451          After changing UCP table:            187
1452          After changing error message table:   43
1453          After changing table of "verbs"       36
1454          After changing table of Posix names   22
1455    
1456        Thanks to the folks working on Gregex for glib for this insight.
1457    
1458    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1459        unicode-properties was also set.
1460    
1461    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1462    
1463    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1464        checked only for CRLF.
1465    
1466    14. Added casts to pcretest.c to avoid compiler warnings.
1467    
1468    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1469    
1470    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1471        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1472        entirely. This removes changes made in 7 above.
1473    
1474    17. The CMake files have been updated, and there is now more information about
1475        building with CMake in the NON-UNIX-USE document.
1476    
1477    
1478    Version 7.3 28-Aug-07
1479  ---------------------  ---------------------
1480    
1481   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 9  Version 7.3 05-Jul-07 Line 1483  Version 7.3 05-Jul-07
1483      brackets there is not right, since it causes compilers to look for an      brackets there is not right, since it causes compilers to look for an
1484      installed pcre.h, not the version that is in the source that is being      installed pcre.h, not the version that is in the source that is being
1485      compiled (which of course may be different). I have changed it back to:      compiled (which of course may be different). I have changed it back to:
1486    
1487        #include "pcre.h"        #include "pcre.h"
   
     I have a vague recollection that the change was concerned with compiling in  
     different directories, but in the new build system, that is taken care of  
     by the VPATH setting the Makefile.  
1488    
1489        I have a vague recollection that the change was concerned with compiling in
1490        different directories, but in the new build system, that is taken care of
1491        by the VPATH setting the Makefile.
1492    
1493     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1494        when the subject happened to end in the byte 0x85 (e.g. if the last
1495        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1496        characters but of course it shouldn't be taken as a newline when it is part
1497        of another character. The bug was that, for an unlimited repeat of . in
1498        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1499        characters when looking for a newline.
1500    
1501     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1502    
1503     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1504        in debug output.
1505    
1506     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1507        long printing in the pcrecpp unittest when running under MinGW.
1508    
1509     6. ESC_K was left out of the EBCDIC table.
1510    
1511     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1512        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1513        limit also applies to "virtual nesting" when a pattern is recursive, and in
1514        this case 1000 isn't so big. I have been able to remove this limit at the
1515        expense of backing off one optimization in certain circumstances. Normally,
1516        when pcre_exec() would call its internal match() function recursively and
1517        immediately return the result unconditionally, it uses a "tail recursion"
1518        feature to save stack. However, when a subpattern that can match an empty
1519        string has an unlimited repetition quantifier, it no longer makes this
1520        optimization. That gives it a stack frame in which to save the data for
1521        checking that an empty string has been matched. Previously this was taken
1522        from the 1000-entry workspace that had been reserved. So now there is no
1523        explicit limit, but more stack is used.
1524    
1525     8. Applied Daniel's patches to solve problems with the import/export magic
1526        syntax that is required for Windows, and which was going wrong for the
1527        pcreposix and pcrecpp parts of the library. These were overlooked when this
1528        problem was solved for the main library.
1529    
1530     9. There were some crude static tests to avoid integer overflow when computing
1531        the size of patterns that contain repeated groups with explicit upper
1532        limits. As the maximum quantifier is 65535, the maximum group length was
1533        set at 30,000 so that the product of these two numbers did not overflow a
1534        32-bit integer. However, it turns out that people want to use groups that
1535        are longer than 30,000 bytes (though not repeat them that many times).
1536        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1537        made it possible to implement the integer overflow checks in a much more
1538        dynamic way, which I have now done. The artificial limitation on group
1539        length has been removed - we now have only the limit on the total length of
1540        the compiled pattern, which depends on the LINK_SIZE setting.
1541    
1542    10. Fixed a bug in the documentation for get/copy named substring when
1543        duplicate names are permitted. If none of the named substrings are set, the
1544        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1545        empty string.
1546    
1547    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1548        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1549        because the ] is interpreted as the first data character and the
1550        terminating ] is not found. PCRE has been made compatible with Perl in this
1551        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1552        cause memory overwriting.
1553    
1554    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1555        string has been matched (to stop an infinite loop). It was not recognizing
1556        a conditional subpattern that could match an empty string if that
1557        subpattern was within another subpattern. For example, it looped when
1558        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1559        condition was not nested. This bug has been fixed.
1560    
1561    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1562        past the start of the subject in the presence of bytes with the top bit
1563        set, for example "\x8aBCD".
1564    
1565    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1566        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1567    
1568    14. Optimized (?!) to (*FAIL).
1569    
1570    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1571        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1572        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1573        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1574        does: it's just the validity check that is more restrictive.
1575    
1576    16. Inserted checks for integer overflows during escape sequence (backslash)
1577        processing, and also fixed erroneous offset values for syntax errors during
1578        backslash processing.
1579    
1580    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1581        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1582    
1583    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1584        caused an overrun.
1585    
1586    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1587        something other than just ASCII characters) inside a group that had an
1588        unlimited repeat caused a loop at compile time (while checking to see
1589        whether the group could match an empty string).
1590    
1591    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1592        [\P{Any}] did so. (Error in the code for printing property names.)
1593    
1594    21. An orphan \E inside a character class could cause a crash.
1595    
1596    22. A repeated capturing bracket such as (A)? could cause a wild memory
1597        reference during compilation.
1598    
1599    23. There are several functions in pcre_compile() that scan along a compiled
1600        expression for various reasons (e.g. to see if it's fixed length for look
1601        behind). There were bugs in these functions when a repeated \p or \P was
1602        present in the pattern. These operators have additional parameters compared
1603        with \d, etc, and these were not being taken into account when moving along
1604        the compiled data. Specifically:
1605    
1606        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1607            length.
1608    
1609        (b) An item such as \pL+ within a repeated group could cause crashes or
1610            loops.
1611    
1612        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1613            "reference to non-existent subpattern" error.
1614    
1615        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1616    
1617    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1618        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1619    
1620    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1621    
1622    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1623        character were causing crashes (broken optimization).
1624    
1625    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1626        \p or \P) caused a compile-time loop.
1627    
1628    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1629        break. For example, the unstudied pattern [\r\n]A does not match the string
1630        "\r\nA" because change 7.0/46 below moves the current point on by two
1631        characters after failing to match at the start. However, the pattern \nA
1632        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1633        the same is true. There doesn't seem any very clean way out of this, but
1634        what I have chosen to do makes the common cases work: PCRE now takes note
1635        of whether there can be an explicit match for \r or \n anywhere in the
1636        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1637        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1638        pattern has explicit CR or LF references.
1639    
1640    29. Added (*CR) etc for changing newline setting at start of pattern.
1641    
1642    
1643  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

Legend:
Removed from v.189  
changed lines
  Added in v.687

  ViewVC Help
Powered by ViewVC 1.1.5