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

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