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revision 67 by nigel, Sat Feb 24 21:40:13 2007 UTC revision 700 by ph10, Tue Sep 20 10:51:26 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.20 12-Sep-2011
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. This bug also affected patterns with classes that started
11       with full stops.
12    
13    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
14       substring, but while checking the failing first alternative, substring 1 is
15       temporarily captured. If the output vector supplied to pcre_exec() was not
16       big enough for this capture, the yield of the function was still zero
17       ("insufficient space for captured substrings"). This cannot be totally fixed
18       without adding another stack variable, which seems a lot of expense for a
19       edge case. However, I have improved the situation in cases such as
20       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
21       fewer than the maximum number of slots in the ovector have been set.
22    
23    3. Related to (2) above: when there are more back references in a pattern than
24       slots in the output vector, pcre_exec() uses temporary memory during
25       matching, and copies in the captures as far as possible afterwards. It was
26       using the entire output vector, but this conflicts with the specification
27       that only 2/3 is used for passing back captured substrings. Now it uses only
28       the first 2/3, for compatibility. This is, of course, another edge case.
29    
30    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
31       main code base, and can be used by building with --enable-jit. When this is
32       done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
33       runtime --no-jit option is given.
34    
35    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
36       ovector, the return from the function was zero, implying that there were
37       other matches that did not fit. The correct "exactly full" value is now
38       returned.
39    
40    6. If a subpattern that was called recursively or as a subroutine contained
41       (*PRUNE) or any other control that caused it to give a non-standard return,
42       invalid errors such as "Error -26 (nested recursion at the same subject
43       position)" or even infinite loops could occur.
44    
45    7. If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
46       computing the minimum length on reaching *ACCEPT, and so ended up with the
47       wrong value of 1 rather than 0. Further investigation indicates that
48       computing a minimum subject length in the presence of *ACCEPT is difficult
49       (think back references, subroutine calls), and so I have changed the code so
50       that no minimum is registered for a pattern that contains *ACCEPT.
51    
52    8. If (*THEN) was present in the first (true) branch of a conditional group,
53       it was not handled as intended.
54    
55    9. Replaced RunTest.bat with the much improved version provided by Sheri
56       Pierce.
57    
58    
59    Version 8.13 16-Aug-2011
60    ------------------------
61    
62    1.  The Unicode data tables have been updated to Unicode 6.0.0.
63    
64    2.  Two minor typos in pcre_internal.h have been fixed.
65    
66    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
67        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
68        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
69    
70    4.  There were a number of related bugs in the code for matching backrefences
71        caselessly in UTF-8 mode when codes for the characters concerned were
72        different numbers of bytes. For example, U+023A and U+2C65 are an upper
73        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
74        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
75        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
76        2-byte code at the end of the subject (it thought there wasn't enough data
77        left).
78    
79    5.  Comprehensive information about what went wrong is now returned by
80        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
81        as the output vector has at least 2 elements. The offset of the start of
82        the failing character and a reason code are placed in the vector.
83    
84    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
85        now returned is for the first byte of the failing character, instead of the
86        last byte inspected. This is an incompatible change, but I hope it is small
87        enough not to be a problem. It makes the returned offset consistent with
88        pcre_exec() and pcre_dfa_exec().
89    
90    7.  pcretest now gives a text phrase as well as the error number when
91        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
92        failure, the offset and reason code are output.
93    
94    8.  When \R was used with a maximizing quantifier it failed to skip backwards
95        over a \r\n pair if the subsequent match failed. Instead, it just skipped
96        back over a single character (\n). This seems wrong (because it treated the
97        two characters as a single entity when going forwards), conflicts with the
98        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
99        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
100        has been changed.
101    
102    9.  Some internal refactoring has changed the processing so that the handling
103        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
104        time (the PCRE_DOTALL option was changed this way some time ago: version
105        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
106        which was always a bit of a fudge. It also means that there is one less
107        argument for the match() function, which reduces its stack requirements
108        slightly. This change also fixes an incompatibility with Perl: the pattern
109        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
110    
111    10. More internal refactoring has drastically reduced the number of recursive
112        calls to match() for possessively repeated groups such as (abc)++ when
113        using pcre_exec().
114    
115    11. While implementing 10, a number of bugs in the handling of groups were
116        discovered and fixed:
117    
118        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
119        (a|)*(?1) gave a compile-time internal error.
120        ((a|)+)+  did not notice that the outer group could match an empty string.
121        (^a|^)+   was not marked as anchored.
122        (.*a|.*)+ was not marked as matching at start or after a newline.
123    
124    12. Yet more internal refactoring has removed another argument from the match()
125        function. Special calls to this function are now indicated by setting a
126        value in a variable in the "match data" data block.
127    
128    13. Be more explicit in pcre_study() instead of relying on "default" for
129        opcodes that mean there is no starting character; this means that when new
130        ones are added and accidentally left out of pcre_study(), testing should
131        pick them up.
132    
133    14. The -s option of pcretest has been documented for ages as being an old
134        synonym of -m (show memory usage). I have changed it to mean "force study
135        for every regex", that is, assume /S for every regex. This is similar to -i
136        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
137        using it. It makes it easier to run collections of tests with and without
138        study enabled, and thereby test pcre_study() more easily. All the standard
139        tests are now run with and without -s (but some patterns can be marked as
140        "never study" - see 20 below).
141    
142    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
143        restoration of the capturing data to the outer values was not happening
144        correctly.
145    
146    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
147        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
148        pattern had matched an empty string, and so incorrectly returned a no
149        match.
150    
151    17. There was optimizing code for the last branch of non-capturing parentheses,
152        and also for the obeyed branch of a conditional subexpression, which used
153        tail recursion to cut down on stack usage. Unfortunately, now that there is
154        the possibility of (*THEN) occurring in these branches, tail recursion is
155        no longer possible because the return has to be checked for (*THEN). These
156        two optimizations have therefore been removed.
157    
158    18. If a pattern containing \R was studied, it was assumed that \R always
159        matched two bytes, thus causing the minimum subject length to be
160        incorrectly computed because \R can also match just one byte.
161    
162    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
163        was incorrectly computed.
164    
165    20. If /S is present twice on a test pattern in pcretest input, it now
166        *disables* studying, thereby overriding the use of -s on the command line
167        (see 14 above). This is necessary for one or two tests to keep the output
168        identical in both cases.
169    
170    21. When (*ACCEPT) was used in an assertion that matched an empty string and
171        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
172    
173    22. When an atomic group that contained a capturing parenthesis was
174        successfully matched, but the branch in which it appeared failed, the
175        capturing was not being forgotten if a higher numbered group was later
176        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
177        group 1 to "a", when in fact it should be unset. This applied to multi-
178        branched capturing and non-capturing groups, repeated or not, and also to
179        positive assertions (capturing in negative assertions does not happen
180        in PCRE) and also to nested atomic groups.
181    
182    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
183        subject after a captured substring, to make it easier to tell which of a
184        number of identical substrings has been captured.
185    
186    24. The way atomic groups are processed by pcre_exec() has been changed so that
187        if they are repeated, backtracking one repetition now resets captured
188        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
189        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
190        "aaa". Previously, it would have been "a". As part of this code
191        refactoring, the way recursive calls are handled has also been changed.
192    
193    25. If an assertion condition captured any substrings, they were not passed
194        back unless some other capturing happened later. For example, if
195        (?(?=(a))a) was matched against "a", no capturing was returned.
196    
197    26. When studying a pattern that contained subroutine calls or assertions,
198        the code for finding the minimum length of a possible match was handling
199        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
200        group 1 called group 2 while simultaneously a separate group 2 called group
201        1). A stack overflow occurred in this case. I have fixed this by limiting
202        the recursion depth to 10.
203    
204    27. Updated RunTest.bat in the distribution to the version supplied by Tom
205        Fortmann. This supports explicit test numbers on the command line, and has
206        argument validation and error reporting.
207    
208    28. An instance of \X with an unlimited repeat could fail if at any point the
209        first character it looked at was a mark character.
210    
211    29. Some minor code refactoring concerning Unicode properties and scripts
212        should reduce the stack requirement of match() slightly.
213    
214    30. Added the '=' option to pcretest to check the setting of unused capturing
215        slots at the end of the pattern, which are documented as being -1, but are
216        not included in the return count.
217    
218    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
219        compiled something random. Now it gives a compile-time error (as does
220        Perl).
221    
222    32. A *MARK encountered during the processing of a positive assertion is now
223        recorded and passed back (compatible with Perl).
224    
225    33. If --only-matching or --colour was set on a pcregrep call whose pattern
226        had alternative anchored branches, the search for a second match in a line
227        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
228        matched the line "0102" twice. The same bug affected patterns that started
229        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
230        twice.
231    
232    34. Previously, PCRE did not allow quantification of assertions. However, Perl
233        does, and because of capturing effects, quantifying parenthesized
234        assertions may at times be useful. Quantifiers are now allowed for
235        parenthesized assertions.
236    
237    35. A minor code tidy in pcre_compile() when checking options for \R usage.
238    
239    36. \g was being checked for fancy things in a character class, when it should
240        just be a literal "g".
241    
242    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
243        appearance of a nested POSIX class supersedes an apparent external class.
244        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
245        unescaped square brackets may also appear as part of class names. For
246        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
247        more like Perl. (But see 8.20/1 above.)
248    
249    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
250        was because it thought it was \N{name}, which is not supported).
251    
252    39. Add minix to OS list not supporting the -S option in pcretest.
253    
254    40. PCRE tries to detect cases of infinite recursion at compile time, but it
255        cannot analyze patterns in sufficient detail to catch mutual recursions
256        such as ((?1))((?2)). There is now a runtime test that gives an error if a
257        subgroup is called recursively as a subpattern for a second time at the
258        same position in the subject string. In previous releases this might have
259        been caught by the recursion limit, or it might have run out of stack.
260    
261    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
262        happen only once. PCRE was, however incorrectly giving a compile time error
263        "recursive call could loop indefinitely" because it cannot analyze the
264        pattern in sufficient detail. The compile time test no longer happens when
265        PCRE is compiling a conditional subpattern, but actual runaway loops are
266        now caught at runtime (see 40 above).
267    
268    42. It seems that Perl allows any characters other than a closing parenthesis
269        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
270        has been changed to be the same.
271    
272    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
273        as not to get warnings when autogen.sh is called. Also changed
274        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
275    
276    44. To help people who use pcregrep to scan files containing exceedingly long
277        lines, the following changes have been made:
278    
279        (a) The default value of the buffer size parameter has been increased from
280            8K to 20K. (The actual buffer used is three times this size.)
281    
282        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
283            PCRE is built.
284    
285        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
286            to be set at run time.
287    
288        (d) Numerical values in pcregrep options can be followed by K or M, for
289            example --buffer-size=50K.
290    
291        (e) If a line being scanned overflows pcregrep's buffer, an error is now
292            given and the return code is set to 2.
293    
294    45. Add a pointer to the latest mark to the callout data block.
295    
296    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
297        partial match of an empty string instead of no match. This was specific to
298        the use of ".".
299    
300    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
301        complete match instead of a partial match. This bug was dependent on both
302        the PCRE_UTF8 and PCRE_DOTALL options being set.
303    
304    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
305        starting byte set, because \b was not being ignored.
306    
307    
308    Version 8.12 15-Jan-2011
309    ------------------------
310    
311    1.  Fixed some typos in the markup of the man pages, and wrote a script that
312        checks for such things as part of the documentation building process.
313    
314    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
315        --match-limit and --recursion-limit options (added for 8.11). In
316        particular, this made one of the standard tests fail. (The integer value
317        went into the wrong half of a long int.)
318    
319    3.  If the --colour option was given to pcregrep with -v (invert match), it
320        did strange things, either producing crazy output, or crashing. It should,
321        of course, ignore a request for colour when reporting lines that do not
322        match.
323    
324    4.  Another pcregrep bug caused similar problems if --colour was specified with
325        -M (multiline) and the pattern match finished with a line ending.
326    
327    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
328        matched in multiline mode, the following line was shown as part of the
329        match. This seems wrong, so I have changed it.
330    
331    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
332        the check for further matches in the same line (so they could be coloured)
333        to overrun the end of the current line. If another match was found, it was
334        incorrectly shown (and then shown again when found in the next line).
335    
336    7.  If pcregrep was compiled under Windows, there was a reference to the
337        function pcregrep_exit() before it was defined. I am assuming this was
338        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
339        reported by a user. I've moved the definition above the reference.
340    
341    
342    Version 8.11 10-Dec-2010
343    ------------------------
344    
345    1.  (*THEN) was not working properly if there were untried alternatives prior
346        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
347        backtracked to try for "b" instead of moving to the next alternative branch
348        at the same level (in this case, to look for "c"). The Perl documentation
349        is clear that when (*THEN) is backtracked onto, it goes to the "next
350        alternative in the innermost enclosing group".
351    
352    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
353        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
354        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
355        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
356        (*THEN).
357    
358    3.  If \s appeared in a character class, it removed the VT character from
359        the class, even if it had been included by some previous item, for example
360        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
361        of \s, but is part of the POSIX "space" class.)
362    
363    4.  A partial match never returns an empty string (because you can always
364        match an empty string at the end of the subject); however the checking for
365        an empty string was starting at the "start of match" point. This has been
366        changed to the "earliest inspected character" point, because the returned
367        data for a partial match starts at this character. This means that, for
368        example, /(?<=abc)def/ gives a partial match for the subject "abc"
369        (previously it gave "no match").
370    
371    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
372        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
373        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
374        has an implication that the given string is incomplete (because a partial
375        match is preferred over a full match). For this reason, these items now
376        give a partial match in this situation. [Aside: previously, the one case
377        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
378        match rather than a full match, which was wrong by the old rules, but is
379        now correct.]
380    
381    6.  There was a bug in the handling of #-introduced comments, recognized when
382        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
383        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
384        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
385        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
386        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
387        places in pcre_compile().
388    
389    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
390        comments when looking ahead for named forward references to subpatterns,
391        the only newline sequence it recognized was NL. It now handles newlines
392        according to the set newline convention.
393    
394    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
395        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
396        cater for a lack of strerror(). These oversights have been fixed.
397    
398    9.  Added --match-limit and --recursion-limit to pcregrep.
399    
400    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
401    
402    11. When the -o option was used, pcregrep was setting a return code of 1, even
403        when matches were found, and --line-buffered was not being honoured.
404    
405    12. Added an optional parentheses number to the -o and --only-matching options
406        of pcregrep.
407    
408    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
409        can match an empty string. The code to do it in pcretest and pcredemo
410        needed fixing:
411    
412        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
413            only one byte after an empty string match just before CRLF (this case
414            just got forgotten; "any" and "anycrlf" were OK).
415    
416        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
417            mode when an empty string match preceded an ASCII character followed by
418            a non-ASCII character. (The code for advancing by one character rather
419            than one byte was nonsense.)
420    
421        (c) The pcredemo.c sample program did not have any code at all to handle
422            the cases when CRLF is a valid newline sequence.
423    
424    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
425        as a starting offset was within the subject string. There is now a new
426        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
427        negative or greater than the length of the string. In order to test this,
428        pcretest is extended to allow the setting of negative starting offsets.
429    
430    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
431        starting offset points to the beginning of a UTF-8 character was
432        unnecessarily clumsy. I tidied it up.
433    
434    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
435        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
436    
437    17. Nobody had reported that the --include_dir option, which was added in
438        release 7.7 should have been called --include-dir (hyphen, not underscore)
439        for compatibility with GNU grep. I have changed it to --include-dir, but
440        left --include_dir as an undocumented synonym, and the same for
441        --exclude-dir, though that is not available in GNU grep, at least as of
442        release 2.5.4.
443    
444    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
445        characters from a string of bytes) have been redefined so as not to use
446        loops, in order to improve performance in some environments. At the same
447        time, I abstracted some of the common code into auxiliary macros to save
448        repetition (this should not affect the compiled code).
449    
450    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
451        compile-time error is now given if \c is not followed by an ASCII
452        character, that is, a byte less than 128. (In EBCDIC mode, the code is
453        different, and any byte value is allowed.)
454    
455    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
456        START_OPTIMIZE option, which is now allowed at compile time - but just
457        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
458        to pcregrep and other applications that have no direct access to PCRE
459        options. The new /Y option in pcretest sets this option when calling
460        pcre_compile().
461    
462    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
463        back references. Groups containing recursive back references were forced to
464        be atomic by that change, but in the case of named groups, the amount of
465        memory required was incorrectly computed, leading to "Failed: internal
466        error: code overflow". This has been fixed.
467    
468    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
469        pcretest.c, to avoid build problems in some Borland environments.
470    
471    
472    Version 8.10 25-Jun-2010
473    ------------------------
474    
475    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
476        THEN.
477    
478    2.  (*ACCEPT) was not working when inside an atomic group.
479    
480    3.  Inside a character class, \B is treated as a literal by default, but
481        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
482        causes the error). The code is unchanged, but I tidied the documentation.
483    
484    4.  Inside a character class, PCRE always treated \R and \X as literals,
485        whereas Perl faults them if its -w option is set. I have changed PCRE so
486        that it faults them when PCRE_EXTRA is set.
487    
488    5.  Added support for \N, which always matches any character other than
489        newline. (It is the same as "." when PCRE_DOTALL is not set.)
490    
491    6.  When compiling pcregrep with newer versions of gcc which may have
492        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
493        declared with attribute warn_unused_result" were given. Just casting the
494        result to (void) does not stop the warnings; a more elaborate fudge is
495        needed. I've used a macro to implement this.
496    
497    7.  Minor change to pcretest.c to avoid a compiler warning.
498    
499    8.  Added four artifical Unicode properties to help with an option to make
500        \s etc use properties (see next item). The new properties are: Xan
501        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
502    
503    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
504        use Unicode properties. (*UCP) at the start of a pattern can be used to set
505        this option. Modified pcretest to add /W to test this facility. Added
506        REG_UCP to make it available via the POSIX interface.
507    
508    10. Added --line-buffered to pcregrep.
509    
510    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
511        studied, and the match started with a letter with a code point greater than
512        127 whose first byte was different to the first byte of the other case of
513        the letter, the other case of this starting letter was not recognized
514        (#976).
515    
516    12. If a pattern that was studied started with a repeated Unicode property
517        test, for example, \p{Nd}+, there was the theoretical possibility of
518        setting up an incorrect bitmap of starting bytes, but fortunately it could
519        not have actually happened in practice until change 8 above was made (it
520        added property types that matched character-matching opcodes).
521    
522    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
523        possible starting bytes for non-anchored patterns.
524    
525    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
526        \R, and also a number of cases that involve Unicode properties, both
527        explicit and implicit when PCRE_UCP is set.
528    
529    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
530        input, it could crash or give wrong results if characters with values
531        greater than 0xc0 were present in the subject string. (Detail: it assumed
532        UTF-8 input when processing these items.)
533    
534    16. Added a lot of (int) casts to avoid compiler warnings in systems where
535        size_t is 64-bit (#991).
536    
537    17. Added a check for running out of memory when PCRE is compiled with
538        --disable-stack-for-recursion (#990).
539    
540    18. If the last data line in a file for pcretest does not have a newline on
541        the end, a newline was missing in the output.
542    
543    19. The default pcre_chartables.c file recognizes only ASCII characters (values
544        less than 128) in its various bitmaps. However, there is a facility for
545        generating tables according to the current locale when PCRE is compiled. It
546        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
547        characters, are recognized by isspace() and therefore were getting set in
548        these tables, and indeed these tables seem to approximate to ISO 8859. This
549        caused a problem in UTF-8 mode when pcre_study() was used to create a list
550        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
551        which of course cannot start UTF-8 characters. I have changed the code so
552        that only real ASCII characters (less than 128) and the correct starting
553        bytes for UTF-8 encodings are set for characters greater than 127 when in
554        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
555        altogether.)
556    
557    20. Added the /T option to pcretest so as to be able to run tests with non-
558        standard character tables, thus making it possible to include the tests
559        used for 19 above in the standard set of tests.
560    
561    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
562        reference to a subpattern the other side of a comment that contains an
563        opening parenthesis caused either an internal compiling error, or a
564        reference to the wrong subpattern.
565    
566    
567    Version 8.02 19-Mar-2010
568    ------------------------
569    
570    1.  The Unicode data tables have been updated to Unicode 5.2.0.
571    
572    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
573        configured.
574    
575    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
576        original author of that file, following a query about its status.
577    
578    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
579        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
580    
581    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
582        quantifier applied to a forward-referencing subroutine call, could compile
583        incorrect code or give the error "internal error: previously-checked
584        referenced subpattern not found".
585    
586    6.  Both MS Visual Studio and Symbian OS have problems with initializing
587        variables to point to external functions. For these systems, therefore,
588        pcre_malloc etc. are now initialized to local functions that call the
589        relevant global functions.
590    
591    7.  There were two entries missing in the vectors called coptable and poptable
592        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
593        I've fixed the data, and added a kludgy way of testing at compile time that
594        the lengths are correct (equal to the number of opcodes).
595    
596    8.  Following on from 7, I added a similar kludge to check the length of the
597        eint vector in pcreposix.c.
598    
599    9.  Error texts for pcre_compile() are held as one long string to avoid too
600        much relocation at load time. To find a text, the string is searched,
601        counting zeros. There was no check for running off the end of the string,
602        which could happen if a new error number was added without updating the
603        string.
604    
605    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
606    
607    11. \K was not working if it appeared in an atomic group or in a group that
608        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
609        \K is "not well defined" if used in an assertion. PCRE now accepts it if
610        the assertion is positive, but not if it is negative.
611    
612    12. Change 11 fortuitously reduced the size of the stack frame used in the
613        "match()" function of pcre_exec.c by one pointer. Forthcoming
614        implementation of support for (*MARK) will need an extra pointer on the
615        stack; I have reserved it now, so that the stack frame size does not
616        decrease.
617    
618    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
619        item in branch that calls a recursion is a subroutine call - as in the
620        second branch in the above example - was incorrectly given the compile-
621        time error "recursive call could loop indefinitely" because pcre_compile()
622        was not correctly checking the subroutine for matching a non-empty string.
623    
624    14. The checks for overrunning compiling workspace could trigger after an
625        overrun had occurred. This is a "should never occur" error, but it can be
626        triggered by pathological patterns such as hundreds of nested parentheses.
627        The checks now trigger 100 bytes before the end of the workspace.
628    
629    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
630    
631    
632    Version 8.01 19-Jan-2010
633    ------------------------
634    
635    1.  If a pattern contained a conditional subpattern with only one branch (in
636        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
637        computed the wrong minimum data length (which is of course zero for such
638        subpatterns). This could cause incorrect "no match" results.
639    
640    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
641        the pattern is reset in the first branch, pcre_compile() failed with
642        "internal error: code overflow at offset...". This happened only when
643        the reset was to the original external option setting. (An optimization
644        abstracts leading options settings into an external setting, which was the
645        cause of this.)
646    
647    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
648        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
649        assertion pattern did not match (meaning that the assertion was true), it
650        was incorrectly treated as false if the SKIP had been reached during the
651        matching. This also applied to assertions used as conditions.
652    
653    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
654        assertion subpattern, including such a pattern used as a condition,
655        unpredictable results occurred, instead of the error return
656        PCRE_ERROR_DFA_UITEM.
657    
658    5.  The C++ GlobalReplace function was not working like Perl for the special
659        situation when an empty string is matched. It now does the fancy magic
660        stuff that is necessary.
661    
662    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
663        removed. (These were left over from very, very early versions of PCRE.)
664    
665    7.  Some cosmetic changes to the code to make life easier when compiling it
666        as part of something else:
667    
668        (a) Change DEBUG to PCRE_DEBUG.
669    
670        (b) In pcre_compile(), rename the member of the "branch_chain" structure
671            called "current" as "current_branch", to prevent a collision with the
672            Linux macro when compiled as a kernel module.
673    
674        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
675            prevent a collision with the Linux macro when compiled as a kernel
676            module.
677    
678    8.  In pcre_compile() there are some checks for integer overflows that used to
679        cast potentially large values to (double). This has been changed to that
680        when building, a check for int64_t is made, and if it is found, it is used
681        instead, thus avoiding the use of floating point arithmetic. (There is no
682        other use of FP in PCRE.) If int64_t is not found, the fallback is to
683        double.
684    
685    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
686        2005 (difference between two addresses compared to an unsigned value).
687    
688    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
689        custom one, because of the following reported problem in Windows:
690    
691          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
692              under Win32.
693          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
694              therefore missing the function definition.
695          - The compiler thus generates a "C" signature for the test function.
696          - The linker fails to find the "C" function.
697          - PCRE fails to configure if asked to do so against libbz2.
698    
699    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
700        messages were output:
701    
702          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
703          rerunning libtoolize, to keep the correct libtool macros in-tree.
704          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
705    
706        I have done both of these things.
707    
708    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
709        most of the time, it *can* run out if it is given a pattern that contains a
710        runaway infinite recursion. I updated the discussion in the pcrestack man
711        page.
712    
713    13. Now that we have gone to the x.xx style of version numbers, the minor
714        version may start with zero. Using 08 or 09 is a bad idea because users
715        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
716        interpreted as invalid octal numbers. I've updated the previous comment in
717        configure.ac, and also added a check that gives an error if 08 or 09 are
718        used.
719    
720    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
721        causing partial matching to fail when the end of the subject matched \W
722        in a UTF-8 pattern where \W was quantified with a minimum of 3.
723    
724    15. There were some discrepancies between the declarations in pcre_internal.h
725        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
726        their definitions. The declarations used "const uschar *" and the
727        definitions used USPTR. Even though USPTR is normally defined as "const
728        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
729        reported that: "This difference in casting confuses some C++ compilers, for
730        example, SunCC recognizes above declarations as different functions and
731        generates broken code for hbpcre." I have changed the declarations to use
732        USPTR.
733    
734    16. GNU libtool is named differently on some systems. The autogen.sh script now
735        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
736        (FreeBSD).
737    
738    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
739        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
740        comment: "Figure out how to create a longlong from a string: strtoll and
741        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
742        instance, but it only takes 2 args instead of 3!"
743    
744    18. A subtle bug concerned with back references has been fixed by a change of
745        specification, with a corresponding code fix. A pattern such as
746        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
747        refers, was giving matches when it shouldn't. For example, xa=xaaa would
748        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
749        same bug. Such groups have to be quantified to be useful, or contained
750        inside another quantified group. (If there's no repetition, the reference
751        can never match.) The problem arises because, having left the group and
752        moved on to the rest of the pattern, a later failure that backtracks into
753        the group uses the captured value from the final iteration of the group
754        rather than the correct earlier one. I have fixed this in PCRE by forcing
755        any group that contains a reference to itself to be an atomic group; that
756        is, there cannot be any backtracking into it once it has completed. This is
757        similar to recursive and subroutine calls.
758    
759    
760    Version 8.00 19-Oct-09
761    ----------------------
762    
763    1.  The table for translating pcre_compile() error codes into POSIX error codes
764        was out-of-date, and there was no check on the pcre_compile() error code
765        being within the table. This could lead to an OK return being given in
766        error.
767    
768    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
769        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
770        in a Windows environment.
771    
772    3.  The pcregrep --count option prints the count for each file even when it is
773        zero, as does GNU grep. However, pcregrep was also printing all files when
774        --files-with-matches was added. Now, when both options are given, it prints
775        counts only for those files that have at least one match. (GNU grep just
776        prints the file name in this circumstance, but including the count seems
777        more useful - otherwise, why use --count?) Also ensured that the
778        combination -clh just lists non-zero counts, with no names.
779    
780    4.  The long form of the pcregrep -F option was incorrectly implemented as
781        --fixed_strings instead of --fixed-strings. This is an incompatible change,
782        but it seems right to fix it, and I didn't think it was worth preserving
783        the old behaviour.
784    
785    5.  The command line items --regex=pattern and --regexp=pattern were not
786        recognized by pcregrep, which required --regex pattern or --regexp pattern
787        (with a space rather than an '='). The man page documented the '=' forms,
788        which are compatible with GNU grep; these now work.
789    
790    6.  No libpcreposix.pc file was created for pkg-config; there was just
791        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
792    
793    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
794        when UCP support is not needed, by modifying the Python script that
795        generates it from Unicode data files. This should not matter if the module
796        is correctly used as a library, but I received one complaint about 50K of
797        unwanted data. My guess is that the person linked everything into his
798        program rather than using a library. Anyway, it does no harm.
799    
800    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
801        was a minimum greater than 1 for a wide character in a possessive
802        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
803        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
804        character. Chaos in the form of incorrect output or a compiling loop could
805        result.
806    
807    9.  The restrictions on what a pattern can contain when partial matching is
808        requested for pcre_exec() have been removed. All patterns can now be
809        partially matched by this function. In addition, if there are at least two
810        slots in the offset vector, the offset of the earliest inspected character
811        for the match and the offset of the end of the subject are set in them when
812        PCRE_ERROR_PARTIAL is returned.
813    
814    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
815        synonymous with PCRE_PARTIAL, for backwards compatibility, and
816        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
817        and may be more useful for multi-segment matching.
818    
819    11. Partial matching with pcre_exec() is now more intuitive. A partial match
820        used to be given if ever the end of the subject was reached; now it is
821        given only if matching could not proceed because another character was
822        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
823        string "Z", which now yields "no match" instead of "partial match". In the
824        case of pcre_dfa_exec(), "no match" is given if every matching path for the
825        final character ended with (*FAIL).
826    
827    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
828        if the pattern had a "must contain" character that was already found in the
829        earlier partial match, unless partial matching was again requested. For
830        example, with the pattern /dog.(body)?/, the "must contain" character is
831        "g". If the first part-match was for the string "dog", restarting with
832        "sbody" failed. This bug has been fixed.
833    
834    13. The string returned by pcre_dfa_exec() after a partial match has been
835        changed so that it starts at the first inspected character rather than the
836        first character of the match. This makes a difference only if the pattern
837        starts with a lookbehind assertion or \b or \B (\K is not supported by
838        pcre_dfa_exec()). It's an incompatible change, but it makes the two
839        matching functions compatible, and I think it's the right thing to do.
840    
841    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
842        so that the demonstration program is easily available in environments where
843        PCRE has not been installed from source.
844    
845    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
846        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
847        library.
848    
849    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
850        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
851        is not the first non-POSIX option to be added. Clearly some people find
852        these options useful.
853    
854    17. If a caller to the POSIX matching function regexec() passes a non-zero
855        value for nmatch with a NULL value for pmatch, the value of
856        nmatch is forced to zero.
857    
858    18. RunGrepTest did not have a test for the availability of the -u option of
859        the diff command, as RunTest does. It now checks in the same way as
860        RunTest, and also checks for the -b option.
861    
862    19. If an odd number of negated classes containing just a single character
863        interposed, within parentheses, between a forward reference to a named
864        subpattern and the definition of the subpattern, compilation crashed with
865        an internal error, complaining that it could not find the referenced
866        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
867        [The bug was that it was starting one character too far in when skipping
868        over the character class, thus treating the ] as data rather than
869        terminating the class. This meant it could skip too much.]
870    
871    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
872        /g option in pcretest when the pattern contains \K, which makes it possible
873        to have an empty string match not at the start, even when the pattern is
874        anchored. Updated pcretest and pcredemo to use this option.
875    
876    21. If the maximum number of capturing subpatterns in a recursion was greater
877        than the maximum at the outer level, the higher number was returned, but
878        with unset values at the outer level. The correct (outer level) value is
879        now given.
880    
881    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
882        PCRE did not set those parentheses (unlike Perl). I have now found a way to
883        make it do so. The string so far is captured, making this feature
884        compatible with Perl.
885    
886    23. The tests have been re-organized, adding tests 11 and 12, to make it
887        possible to check the Perl 5.10 features against Perl 5.10.
888    
889    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
890        pattern matches a fixed length string. PCRE did not allow this; now it
891        does. Neither allows recursion.
892    
893    25. I finally figured out how to implement a request to provide the minimum
894        length of subject string that was needed in order to match a given pattern.
895        (It was back references and recursion that I had previously got hung up
896        on.) This code has now been added to pcre_study(); it finds a lower bound
897        to the length of subject needed. It is not necessarily the greatest lower
898        bound, but using it to avoid searching strings that are too short does give
899        some useful speed-ups. The value is available to calling programs via
900        pcre_fullinfo().
901    
902    26. While implementing 25, I discovered to my embarrassment that pcretest had
903        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
904        study optimizations had never been tested with that matching function.
905        Oops. What is worse, even when it was passed study data, there was a bug in
906        pcre_dfa_exec() that meant it never actually used it. Double oops. There
907        were also very few tests of studied patterns with pcre_dfa_exec().
908    
909    27. If (?| is used to create subpatterns with duplicate numbers, they are now
910        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
911        on the other side of the coin, they are no longer allowed to have different
912        names, because these cannot be distinguished in PCRE, and this has caused
913        confusion. (This is a difference from Perl.)
914    
915    28. When duplicate subpattern names are present (necessarily with different
916        numbers, as required by 27 above), and a test is made by name in a
917        conditional pattern, either for a subpattern having been matched, or for
918        recursion in such a pattern, all the associated numbered subpatterns are
919        tested, and the overall condition is true if the condition is true for any
920        one of them. This is the way Perl works, and is also more like the way
921        testing by number works.
922    
923    
924    Version 7.9 11-Apr-09
925    ---------------------
926    
927    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
928        (pcretest), all targets were linked against these libraries. This included
929        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
930        libraries. This caused unwanted dependencies to be created. This problem
931        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
932        pcretest is linked with readline.
933    
934    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
935        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
936        moved outside it again, because FALSE and TRUE are already defined in AIX,
937        but BOOL is not.
938    
939    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
940        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
941    
942    4.  The pcregrep documentation said spaces were inserted as well as colons (or
943        hyphens) following file names and line numbers when outputting matching
944        lines. This is not true; no spaces are inserted. I have also clarified the
945        wording for the --colour (or --color) option.
946    
947    5.  In pcregrep, when --colour was used with -o, the list of matching strings
948        was not coloured; this is different to GNU grep, so I have changed it to be
949        the same.
950    
951    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
952        each matching line was coloured. Now it goes on to look for further matches
953        of any of the test patterns, which is the same behaviour as GNU grep.
954    
955    7.  A pattern that could match an empty string could cause pcregrep to loop; it
956        doesn't make sense to accept an empty string match in pcregrep, so I have
957        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
958        seems to be how GNU grep behaves.
959    
960    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
961        start or after a newline", because the conditional assertion was not being
962        correctly handled. The rule now is that both the assertion and what follows
963        in the first alternative must satisfy the test.
964    
965    9.  If auto-callout was enabled in a pattern with a conditional group whose
966        condition was an assertion, PCRE could crash during matching, both with
967        pcre_exec() and pcre_dfa_exec().
968    
969    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
970        used for matching.
971    
972    11. Unicode property support in character classes was not working for
973        characters (bytes) greater than 127 when not in UTF-8 mode.
974    
975    12. Added the -M command line option to pcretest.
976    
977    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
978    
979    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
980    
981    16. Added comments and documentation about mis-use of no_arg in the C++
982        wrapper.
983    
984    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
985        from Martin Jerabek that uses macro names for all relevant character and
986        string constants.
987    
988    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
989        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
990        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
991        these, but not everybody uses configure.
992    
993    19. A conditional group that had only one branch was not being correctly
994        recognized as an item that could match an empty string. This meant that an
995        enclosing group might also not be so recognized, causing infinite looping
996        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
997        with the subject "ab", where knowledge that the repeated group can match
998        nothing is needed in order to break the loop.
999    
1000    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1001        exec(), but without supplying a callout function, matching went wrong.
1002    
1003    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1004        leak if the size of the offset vector was greater than 30. When the vector
1005        is smaller, the saved offsets during recursion go onto a local stack
1006        vector, but for larger vectors malloc() is used. It was failing to free
1007        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1008        error, in fact).
1009    
1010    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1011        heapframe that is used only when UTF-8 support is enabled. This caused no
1012        problem, but was untidy.
1013    
1014    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1015        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1016        included within another project.
1017    
1018    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1019        slightly modified by me:
1020    
1021          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1022              not building pcregrep.
1023    
1024          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1025              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1026    
1027    25. Forward references, both numeric and by name, in patterns that made use of
1028        duplicate group numbers, could behave incorrectly or give incorrect errors,
1029        because when scanning forward to find the reference group, PCRE was not
1030        taking into account the duplicate group numbers. A pattern such as
1031        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1032    
1033    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1034        the feature of a custom pointer more persuasive (as requested by a user).
1035    
1036    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1037        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1038        pre-defined.
1039    
1040    28. Added support for (*UTF8) at the start of a pattern.
1041    
1042    29. Arrange for flags added by the "release type" setting in CMake to be shown
1043        in the configuration summary.
1044    
1045    
1046    Version 7.8 05-Sep-08
1047    ---------------------
1048    
1049    1.  Replaced UCP searching code with optimized version as implemented for Ad
1050        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1051        stage table and inline lookup instead of a function, giving speed ups of 2
1052        to 5 times on some simple patterns that I tested. Permission was given to
1053        distribute the MultiStage2.py script that generates the tables (it's not in
1054        the tarball, but is in the Subversion repository).
1055    
1056    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1057        scripts.
1058    
1059    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1060        a group with a zero qualifier. The result of the study could be incorrect,
1061        or the function might crash, depending on the pattern.
1062    
1063    4.  Caseless matching was not working for non-ASCII characters in back
1064        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1065        It now works when Unicode Property Support is available.
1066    
1067    5.  In pcretest, an escape such as \x{de} in the data was always generating
1068        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1069        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1070        truncation.
1071    
1072    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1073    
1074    7.  Added two (int) casts to pcregrep when printing the difference of two
1075        pointers, in case they are 64-bit values.
1076    
1077    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1078        test 2 if it fails.
1079    
1080    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1081        and a #define of that name to empty if it is not externally set. This is to
1082        allow users of MSVC to set it if necessary.
1083    
1084    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1085        the convenience functions in the pcre_get.c source file.
1086    
1087    11. An option change at the start of a pattern that had top-level alternatives
1088        could cause overwriting and/or a crash. This command provoked a crash in
1089        some environments:
1090    
1091          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1092    
1093        This potential security problem was recorded as CVE-2008-2371.
1094    
1095    12. For a pattern where the match had to start at the beginning or immediately
1096        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1097        pcre_dfa_exec() could read past the end of the passed subject if there was
1098        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1099        pcretest so that it places the subject at the end of its malloc-ed buffer.
1100    
1101    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1102        exec() might read past the end of the data buffer in UTF-8 mode.
1103    
1104    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1105        the data contained the byte 0x85 as part of a UTF-8 character within its
1106        first line. This applied both to normal and DFA matching.
1107    
1108    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1109        /^[^d]*?$/8 failed to match "abc".
1110    
1111    16. Added a missing copyright notice to pcrecpp_internal.h.
1112    
1113    17. Make it more clear in the documentation that values returned from
1114        pcre_exec() in ovector are byte offsets, not character counts.
1115    
1116    18. Tidied a few places to stop certain compilers from issuing warnings.
1117    
1118    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1119        supplied by Stefan Weber. I made a further small update for 7.8 because
1120        there is a change of source arrangements: the pcre_searchfuncs.c module is
1121        replaced by pcre_ucd.c.
1122    
1123    
1124    Version 7.7 07-May-08
1125    ---------------------
1126    
1127    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1128        a string to a long long, pretend we don't even have a long long." This is
1129        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1130    
1131    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1132        pre-7.6 versions, which defined a global no_arg variable instead of putting
1133        it in the RE class. (See also #8 below.)
1134    
1135    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1136        Lopes.
1137    
1138    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1139    
1140        (1) The include/exclude patterns were being applied to the whole pathnames
1141            of files, instead of just to the final components.
1142    
1143        (2) If there was more than one level of directory, the subdirectories were
1144            skipped unless they satisfied the include/exclude conditions. This is
1145            inconsistent with GNU grep (and could even be seen as contrary to the
1146            pcregrep specification - which I improved to make it absolutely clear).
1147            The action now is always to scan all levels of directory, and just
1148            apply the include/exclude patterns to regular files.
1149    
1150    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1151        --exclude_dir in the tests to avoid scanning .svn directories.
1152    
1153    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1154        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1155        doesn't support NULs in patterns.
1156    
1157    7.  Added some missing "const"s to declarations of static tables in
1158        pcre_compile.c and pcre_dfa_exec.c.
1159    
1160    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1161        caused by fix #2  above. (Subsequently also a second patch to fix the
1162        first patch. And a third patch - this was a messy problem.)
1163    
1164    9.  Applied Craig's patch to remove the use of push_back().
1165    
1166    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1167        matching function regexec().
1168    
1169    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1170        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1171        references. PCRE supports relative numbers with this syntax (I don't think
1172        Oniguruma does).
1173    
1174    12. Previously, a group with a zero repeat such as (...){0} was completely
1175        omitted from the compiled regex. However, this means that if the group
1176        was called as a subroutine from elsewhere in the pattern, things went wrong
1177        (an internal error was given). Such groups are now left in the compiled
1178        pattern, with a new opcode that causes them to be skipped at execution
1179        time.
1180    
1181    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1182        to the way PCRE behaves:
1183    
1184        (a) A lone ] character is dis-allowed (Perl treats it as data).
1185    
1186        (b) A back reference to an unmatched subpattern matches an empty string
1187            (Perl fails the current match path).
1188    
1189        (c) A data ] in a character class must be notated as \] because if the
1190            first data character in a class is ], it defines an empty class. (In
1191            Perl it is not possible to have an empty class.) The empty class []
1192            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1193            The negative empty class [^] matches any one character, independently
1194            of the DOTALL setting.
1195    
1196    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1197        non-existent subpattern following a character class starting with ']' and
1198        containing () gave an internal compiling error instead of "reference to
1199        non-existent subpattern". Fortunately, when the pattern did exist, the
1200        compiled code was correct. (When scanning forwards to check for the
1201        existencd of the subpattern, it was treating the data ']' as terminating
1202        the class, so got the count wrong. When actually compiling, the reference
1203        was subsequently set up correctly.)
1204    
1205    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1206        it was being rejected as not supported by pcre_dfa_exec(), even though
1207        other assertions are supported. I have made pcre_dfa_exec() support
1208        (*FAIL).
1209    
1210    16. The implementation of 13c above involved the invention of a new opcode,
1211        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1212        cannot be changed at match time, I realized I could make a small
1213        improvement to matching performance by compiling OP_ALLANY instead of
1214        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1215        on the OP_ANY path.
1216    
1217    17. Compiling pcretest on Windows with readline support failed without the
1218        following two fixes: (1) Make the unistd.h include conditional on
1219        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1220    
1221    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1222        ncurses library to be included for pcretest when ReadLine support is
1223        requested, but also to allow for it to be overridden. This patch came from
1224        Daniel Bergström.
1225    
1226    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1227        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1228        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1229        spotting this.
1230    
1231    
1232    Version 7.6 28-Jan-08
1233    ---------------------
1234    
1235    1.  A character class containing a very large number of characters with
1236        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1237        overflow.
1238    
1239    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1240        HAVE_LONG_LONG is not defined.
1241    
1242    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1243        bring them up to date and include new features. This patch includes:
1244    
1245        - Fixed PH's badly added libz and libbz2 support.
1246        - Fixed a problem with static linking.
1247        - Added pcredemo. [But later removed - see 7 below.]
1248        - Fixed dftables problem and added an option.
1249        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1250            HAVE_LONG_LONG.
1251        - Added readline support for pcretest.
1252        - Added an listing of the option settings after cmake has run.
1253    
1254    4.  A user submitted a patch to Makefile that makes it easy to create
1255        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1256        Makefile.am that cause it to include this special target, without
1257        affecting anything else. Note that the same mingw target plus all
1258        the other distribution libraries and programs are now supported
1259        when configuring with CMake (see 6 below) instead of with
1260        Configure/Make.
1261    
1262    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1263        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1264        exported in the Windows port". It has not yet been confirmed that the patch
1265        solves the problem, but it does no harm.
1266    
1267    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1268        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1269        with CMake, and also correct the comment about stack recursion.
1270    
1271    7.  Remove the automatic building of pcredemo from the ./configure system and
1272        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1273        of a program that users should build themselves after PCRE is installed, so
1274        building it automatically is not really right. What is more, it gave
1275        trouble in some build environments.
1276    
1277    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1278    
1279    
1280    Version 7.5 10-Jan-08
1281    ---------------------
1282    
1283    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1284        values in parens when parsing an RE using the C++ wrapper."
1285    
1286    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1287        Characters greater than 255 were excluded from the class instead of being
1288        included.
1289    
1290    3.  The same bug as (2) above applied to negated POSIX classes such as
1291        [:^space:].
1292    
1293    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1294        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1295        I have changed it.
1296    
1297    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1298        first named subpattern) and a construct such as (?&a) would reference the
1299        first named subpattern whose name started with "a" (in other words, the
1300        length check was missing). Both these problems are fixed. "Subpattern name
1301        expected" is now given for (?&) (a zero-length name), and this patch also
1302        makes it give the same error for \k'' (previously it complained that that
1303        was a reference to a non-existent subpattern).
1304    
1305    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1306        this is right because (?- can be followed by option settings as well as by
1307        digits. I have, however, made the messages clearer.
1308    
1309    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1310        than the number used in the conditional) now cause a compile-time error.
1311        This is actually not compatible with Perl, which accepts such patterns, but
1312        treats the conditional as always being FALSE (as PCRE used to), but it
1313        seems to me that giving a diagnostic is better.
1314    
1315    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1316        and messages.
1317    
1318    9.  Fix two occurrences of "backslash" in comments that should have been
1319        "backspace".
1320    
1321    10. Remove two redundant lines of code that can never be obeyed (their function
1322        was moved elsewhere).
1323    
1324    11. The program that makes PCRE's Unicode character property table had a bug
1325        which caused it to generate incorrect table entries for sequences of
1326        characters that have the same character type, but are in different scripts.
1327        It amalgamated them into a single range, with the script of the first of
1328        them. In other words, some characters were in the wrong script. There were
1329        thirteen such cases, affecting characters in the following ranges:
1330    
1331          U+002b0 - U+002c1
1332          U+0060c - U+0060d
1333          U+0061e - U+00612
1334          U+0064b - U+0065e
1335          U+0074d - U+0076d
1336          U+01800 - U+01805
1337          U+01d00 - U+01d77
1338          U+01d9b - U+01dbf
1339          U+0200b - U+0200f
1340          U+030fc - U+030fe
1341          U+03260 - U+0327f
1342          U+0fb46 - U+0fbb1
1343          U+10450 - U+1049d
1344    
1345    12. The -o option (show only the matching part of a line) for pcregrep was not
1346        compatible with GNU grep in that, if there was more than one match in a
1347        line, it showed only the first of them. It now behaves in the same way as
1348        GNU grep.
1349    
1350    13. If the -o and -v options were combined for pcregrep, it printed a blank
1351        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1352        does the same. The return code can be used to tell if there were any
1353        non-matching lines.
1354    
1355    14. Added --file-offsets and --line-offsets to pcregrep.
1356    
1357    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1358        infinitely looping recursion. The bug was that positive lookaheads were not
1359        being skipped when checking for a possible empty match (negative lookaheads
1360        and both kinds of lookbehind were skipped).
1361    
1362    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1363        inclusion of <windows.h> to before rather than after the definition of
1364        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1365    
1366    17. Specifying a possessive quantifier with a specific limit for a Unicode
1367        character property caused pcre_compile() to compile bad code, which led at
1368        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1369        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1370        caused the error; without that there was no problem.
1371    
1372    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1373    
1374    19. Added --enable-pcretest-libreadline.
1375    
1376    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1377        RE::GlobalReplace(). As a result, the number of replacements returned was
1378        double what it should be. I removed one of the increments, but Craig sent a
1379        later patch that removed the other one (the right fix) and added unit tests
1380        that check the return values (which was not done before).
1381    
1382    21. Several CMake things:
1383    
1384        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1385            the names libpcre and libpcreposix, not just pcre and pcreposix.
1386    
1387        (2) The above change means that pcretest and pcregrep are now correctly
1388            linked with the newly-built libraries, not previously installed ones.
1389    
1390        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1391    
1392    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1393        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1394        UTF-8 newline character). The key issue is that the pattern starts .*;
1395        this means that the match must be either at the beginning, or after a
1396        newline. The bug was in the code for advancing after a failed match and
1397        checking that the new position followed a newline. It was not taking
1398        account of UTF-8 characters correctly.
1399    
1400    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1401        character classes. PCRE was not treating the sequence [:...:] as a
1402        character class unless the ... were all letters. Perl, however, seems to
1403        allow any characters between [: and :], though of course it rejects as
1404        unknown any "names" that contain non-letters, because all the known class
1405        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1406        for example, whereas PCRE did not - it did not recognize a POSIX character
1407        class. This seemed a bit dangerous, so the code has been changed to be
1408        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1409        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1410        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1411        Perl does, and where it didn't before.
1412    
1413    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1414        Windows environments %n is disabled by default.
1415    
1416    
1417    Version 7.4 21-Sep-07
1418    ---------------------
1419    
1420    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1421        means that a class such as [\s] counted as "explicit reference to CR or
1422        LF". That isn't really right - the whole point of the change was to try to
1423        help when there was an actual mention of one of the two characters. So now
1424        the change happens only if \r or \n (or a literal CR or LF) character is
1425        encountered.
1426    
1427    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1428        of both had grown to the point where there were only 3 bits left.
1429        Fortunately, there was spare space in the data structure, and so I have
1430        moved the internal flags into a new 16-bit field to free up more option
1431        bits.
1432    
1433    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1434        but did not set the internal JCHANGED flag - either of these is enough to
1435        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1436        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1437        start sets both bits.
1438    
1439    4.  Added options (at build time, compile time, exec time) to change \R from
1440        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1441    
1442    5.  doc/pcresyntax.html was missing from the distribution.
1443    
1444    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1445        compatibility, even though it is no longer used.
1446    
1447    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1448        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1449        windows.h file is present (where different names are used). [This was
1450        reversed later after testing - see 16 below.]
1451    
1452    8.  Changed all #include <config.h> to #include "config.h". There were also
1453        some further <pcre.h> cases that I changed to "pcre.h".
1454    
1455    9.  When pcregrep was used with the --colour option, it missed the line ending
1456        sequence off the lines that it output.
1457    
1458    10. It was pointed out to me that arrays of string pointers cause lots of
1459        relocations when a shared library is dynamically loaded. A technique of
1460        using a single long string with a table of offsets can drastically reduce
1461        these. I have refactored PCRE in four places to do this. The result is
1462        dramatic:
1463    
1464          Originally:                          290
1465          After changing UCP table:            187
1466          After changing error message table:   43
1467          After changing table of "verbs"       36
1468          After changing table of Posix names   22
1469    
1470        Thanks to the folks working on Gregex for glib for this insight.
1471    
1472    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1473        unicode-properties was also set.
1474    
1475    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1476    
1477    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1478        checked only for CRLF.
1479    
1480    14. Added casts to pcretest.c to avoid compiler warnings.
1481    
1482    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1483    
1484    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1485        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1486        entirely. This removes changes made in 7 above.
1487    
1488    17. The CMake files have been updated, and there is now more information about
1489        building with CMake in the NON-UNIX-USE document.
1490    
1491    
1492    Version 7.3 28-Aug-07
1493    ---------------------
1494    
1495     1. In the rejigging of the build system that eventually resulted in 7.1, the
1496        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1497        brackets there is not right, since it causes compilers to look for an
1498        installed pcre.h, not the version that is in the source that is being
1499        compiled (which of course may be different). I have changed it back to:
1500    
1501          #include "pcre.h"
1502    
1503        I have a vague recollection that the change was concerned with compiling in
1504        different directories, but in the new build system, that is taken care of
1505        by the VPATH setting the Makefile.
1506    
1507     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1508        when the subject happened to end in the byte 0x85 (e.g. if the last
1509        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1510        characters but of course it shouldn't be taken as a newline when it is part
1511        of another character. The bug was that, for an unlimited repeat of . in
1512        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1513        characters when looking for a newline.
1514    
1515     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1516    
1517     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1518        in debug output.
1519    
1520     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1521        long printing in the pcrecpp unittest when running under MinGW.
1522    
1523     6. ESC_K was left out of the EBCDIC table.
1524    
1525     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1526        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1527        limit also applies to "virtual nesting" when a pattern is recursive, and in
1528        this case 1000 isn't so big. I have been able to remove this limit at the
1529        expense of backing off one optimization in certain circumstances. Normally,
1530        when pcre_exec() would call its internal match() function recursively and
1531        immediately return the result unconditionally, it uses a "tail recursion"
1532        feature to save stack. However, when a subpattern that can match an empty
1533        string has an unlimited repetition quantifier, it no longer makes this
1534        optimization. That gives it a stack frame in which to save the data for
1535        checking that an empty string has been matched. Previously this was taken
1536        from the 1000-entry workspace that had been reserved. So now there is no
1537        explicit limit, but more stack is used.
1538    
1539     8. Applied Daniel's patches to solve problems with the import/export magic
1540        syntax that is required for Windows, and which was going wrong for the
1541        pcreposix and pcrecpp parts of the library. These were overlooked when this
1542        problem was solved for the main library.
1543    
1544     9. There were some crude static tests to avoid integer overflow when computing
1545        the size of patterns that contain repeated groups with explicit upper
1546        limits. As the maximum quantifier is 65535, the maximum group length was
1547        set at 30,000 so that the product of these two numbers did not overflow a
1548        32-bit integer. However, it turns out that people want to use groups that
1549        are longer than 30,000 bytes (though not repeat them that many times).
1550        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1551        made it possible to implement the integer overflow checks in a much more
1552        dynamic way, which I have now done. The artificial limitation on group
1553        length has been removed - we now have only the limit on the total length of
1554        the compiled pattern, which depends on the LINK_SIZE setting.
1555    
1556    10. Fixed a bug in the documentation for get/copy named substring when
1557        duplicate names are permitted. If none of the named substrings are set, the
1558        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1559        empty string.
1560    
1561    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1562        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1563        because the ] is interpreted as the first data character and the
1564        terminating ] is not found. PCRE has been made compatible with Perl in this
1565        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1566        cause memory overwriting.
1567    
1568    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1569        string has been matched (to stop an infinite loop). It was not recognizing
1570        a conditional subpattern that could match an empty string if that
1571        subpattern was within another subpattern. For example, it looped when
1572        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1573        condition was not nested. This bug has been fixed.
1574    
1575    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1576        past the start of the subject in the presence of bytes with the top bit
1577        set, for example "\x8aBCD".
1578    
1579    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1580        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1581    
1582    14. Optimized (?!) to (*FAIL).
1583    
1584    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1585        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1586        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1587        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1588        does: it's just the validity check that is more restrictive.
1589    
1590    16. Inserted checks for integer overflows during escape sequence (backslash)
1591        processing, and also fixed erroneous offset values for syntax errors during
1592        backslash processing.
1593    
1594    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1595        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1596    
1597    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1598        caused an overrun.
1599    
1600    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1601        something other than just ASCII characters) inside a group that had an
1602        unlimited repeat caused a loop at compile time (while checking to see
1603        whether the group could match an empty string).
1604    
1605    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1606        [\P{Any}] did so. (Error in the code for printing property names.)
1607    
1608    21. An orphan \E inside a character class could cause a crash.
1609    
1610    22. A repeated capturing bracket such as (A)? could cause a wild memory
1611        reference during compilation.
1612    
1613    23. There are several functions in pcre_compile() that scan along a compiled
1614        expression for various reasons (e.g. to see if it's fixed length for look
1615        behind). There were bugs in these functions when a repeated \p or \P was
1616        present in the pattern. These operators have additional parameters compared
1617        with \d, etc, and these were not being taken into account when moving along
1618        the compiled data. Specifically:
1619    
1620        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1621            length.
1622    
1623        (b) An item such as \pL+ within a repeated group could cause crashes or
1624            loops.
1625    
1626        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1627            "reference to non-existent subpattern" error.
1628    
1629        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1630    
1631    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1632        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1633    
1634    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1635    
1636    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1637        character were causing crashes (broken optimization).
1638    
1639    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1640        \p or \P) caused a compile-time loop.
1641    
1642    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1643        break. For example, the unstudied pattern [\r\n]A does not match the string
1644        "\r\nA" because change 7.0/46 below moves the current point on by two
1645        characters after failing to match at the start. However, the pattern \nA
1646        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1647        the same is true. There doesn't seem any very clean way out of this, but
1648        what I have chosen to do makes the common cases work: PCRE now takes note
1649        of whether there can be an explicit match for \r or \n anywhere in the
1650        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1651        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1652        pattern has explicit CR or LF references.
1653    
1654    29. Added (*CR) etc for changing newline setting at start of pattern.
1655    
1656    
1657    Version 7.2 19-Jun-07
1658    ---------------------
1659    
1660     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1661        which is apparently normally available under Windows.
1662    
1663     2. Re-jig the pcregrep tests with different newline settings in an attempt
1664        to make them independent of the local environment's newline setting.
1665    
1666     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1667    
1668     4. Some of the "internals" tests were previously cut out when the link size
1669        was not 2, because the output contained actual offsets. The recent new
1670        "Z" feature of pcretest means that these can be cut out, making the tests
1671        usable with all link sizes.
1672    
1673     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1674        stack recursion. This gives a massive performance boost under BSD, but just
1675        a small improvement under Linux. However, it saves one field in the frame
1676        in all cases.
1677    
1678     6. Added more features from the forthcoming Perl 5.10:
1679    
1680        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1681            recursion call. It refers to the nth most recently opened parentheses.
1682    
1683        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1684            to be opened parentheses.
1685    
1686        (c) Conditions that refer to capturing parentheses can be specified
1687            relatively, for example, (?(-2)... or (?(+3)...
1688    
1689        (d) \K resets the start of the current match so that everything before
1690            is not part of it.
1691    
1692        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1693    
1694        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1695            reference syntax.
1696    
1697        (g) (?| introduces a group in which the numbering of parentheses in each
1698            alternative starts with the same number.
1699    
1700        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1701    
1702     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1703        PCRE_INFO_JCHANGED.
1704    
1705     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1706        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1707        for detecting groups that can match an empty string.
1708    
1709     9. A pattern with a very large number of alternatives (more than several
1710        hundred) was running out of internal workspace during the pre-compile
1711        phase, where pcre_compile() figures out how much memory will be needed. A
1712        bit of new cunning has reduced the workspace needed for groups with
1713        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1714        workspace instead of running out of the 4096 that are available.
1715    
1716    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1717    
1718    11. Applied patch from Google to remove an optimization that didn't quite work.
1719        The report of the bug said:
1720    
1721          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1722          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1723          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1724    
1725    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1726        it matched the wrong number of bytes.
1727    
1728    
1729    Version 7.1 24-Apr-07
1730    ---------------------
1731    
1732     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1733        that is more "standard", making use of automake and other Autotools. There
1734        is some re-arrangement of the files and adjustment of comments consequent
1735        on this.
1736    
1737     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1738        for recursive directory scanning broke on some systems because the files
1739        are not scanned in any specific order and on different systems the order
1740        was different. A call to "sort" has been inserted into RunGrepTest for the
1741        approprate test as a short-term fix. In the longer term there may be an
1742        alternative.
1743    
1744     3. I had an email from Eric Raymond about problems translating some of PCRE's
1745        man pages to HTML (despite the fact that I distribute HTML pages, some
1746        people do their own conversions for various reasons). The problems
1747        concerned the use of low-level troff macros .br and .in. I have therefore
1748        removed all such uses from the man pages (some were redundant, some could
1749        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1750        HTML has been updated to handle .nf/.fi and to complain if it encounters
1751        .br or .in.
1752    
1753     4. Updated comments in configure.ac that get placed in config.h.in and also
1754        arranged for config.h to be included in the distribution, with the name
1755        config.h.generic, for the benefit of those who have to compile without
1756        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1757    
1758     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1759        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1760        makevp.bat for the current PCRE, using the additional files
1761        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1762    
1763     6. A Windows user reported a minor discrepancy with test 2, which turned out
1764        to be caused by a trailing space on an input line that had got lost in his
1765        copy. The trailing space was an accident, so I've just removed it.
1766    
1767     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1768        that is needed.
1769    
1770     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1771        as "const" (a) because they are and (b) because it helps the PHP
1772        maintainers who have recently made a script to detect big data structures
1773        in the php code that should be moved to the .rodata section. I remembered
1774        to update Builducptable as well, so it won't revert if ucptable.h is ever
1775        re-created.
1776    
1777     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1778        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1779        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1780        support is not required. This saves 1.5-2K of code, which is important in
1781        some applications.
1782    
1783        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1784        so as not to refer to the tables, even though these functions will never be
1785        called when UTF-8 support is disabled. Otherwise there are problems with a
1786        shared library.
1787    
1788    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1789    
1790        (a) It was defining its arguments as char * instead of void *.
1791    
1792        (b) It was assuming that all moves were upwards in memory; this was true
1793            a long time ago when I wrote it, but is no longer the case.
1794    
1795        The emulated memove() is provided for those environments that have neither
1796        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1797        is clearly not the case, as these two bugs were recently reported.
1798    
1799    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1800        and Detrail to create the HTML documentation, the .txt form of the man
1801        pages, and it removes trailing spaces from listed files. It also creates
1802        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1803        case, it wraps all the #defines with #ifndefs. This script should be run
1804        before "make dist".
1805    
1806    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1807        with Unicode property support.
1808    
1809        (a) For a maximizing quantifier, if the two different cases of the
1810            character were of different lengths in their UTF-8 codings (there are
1811            some cases like this - I found 11), and the matching function had to
1812            back up over a mixture of the two cases, it incorrectly assumed they
1813            were both the same length.
1814    
1815        (b) When PCRE was configured to use the heap rather than the stack for
1816            recursion during matching, it was not correctly preserving the data for
1817            the other case of a UTF-8 character when checking ahead for a match
1818            while processing a minimizing repeat. If the check also involved
1819            matching a wide character, but failed, corruption could cause an
1820            erroneous result when trying to check for a repeat of the original
1821            character.
1822    
1823    13. Some tidying changes to the testing mechanism:
1824    
1825        (a) The RunTest script now detects the internal link size and whether there
1826            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1827            values substituted by "configure". (The RunGrepTest script already did
1828            this for UTF-8.) The configure.ac script no longer substitutes the
1829            relevant variables.
1830    
1831        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1832            with length and offset values. This means that the output is different
1833            for different internal link sizes. Test 2 is skipped for link sizes
1834            other than 2 because of this, bypassing the problem. Unfortunately,
1835            there was also a test in test 3 (the locale tests) that used /B and
1836            failed for link sizes other than 2. Rather than cut the whole test out,
1837            I have added a new /Z option to pcretest that replaces the length and
1838            offset values with spaces. This is now used to make test 3 independent
1839            of link size. (Test 2 will be tidied up later.)
1840    
1841    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1842        segmentation fault instead of returning the appropriate error message.
1843    
1844    15. In multiline mode when the newline sequence was set to "any", the pattern
1845        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1846        This doesn't seem right; it now treats the CRLF combination as the line
1847        ending, and so does not match in that case. It's only a pattern such as ^$
1848        that would hit this one: something like ^ABC$ would have failed after \r
1849        and then tried again after \r\n.
1850    
1851    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1852        in an attempt to make files that differ only in their line terminators
1853        compare equal. This works on Linux.
1854    
1855    17. Under certain error circumstances pcregrep might try to free random memory
1856        as it exited. This is now fixed, thanks to valgrind.
1857    
1858    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1859        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1860        was because its rules for how to advance for /g after matching an empty
1861        string at the end of a line did not allow for this case. They now check for
1862        it specially.
1863    
1864    20. pcretest is supposed to handle patterns and data of any length, by
1865        extending its buffers when necessary. It was getting this wrong when the
1866        buffer for a data line had to be extended.
1867    
1868    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1869        CRLF as a newline sequence.
1870    
1871    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1872        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1873        I have nevertheless tidied it up.
1874    
1875    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1876    
1877    24. Added a man page for pcre-config.
1878    
1879    
1880    Version 7.0 19-Dec-06
1881    ---------------------
1882    
1883     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1884        moving to gcc 4.1.1.
1885    
1886     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1887        sys/time.h, which is documented as needed for this function. It doesn't
1888        seem to matter on Linux, but it showed up on some releases of OS X.
1889    
1890     3. It seems that there are systems where bytes whose values are greater than
1891        127 match isprint() in the "C" locale. The "C" locale should be the
1892        default when a C program starts up. In most systems, only ASCII printing
1893        characters match isprint(). This difference caused the output from pcretest
1894        to vary, making some of the tests fail. I have changed pcretest so that:
1895    
1896        (a) When it is outputting text in the compiled version of a pattern, bytes
1897            other than 32-126 are always shown as hex escapes.
1898    
1899        (b) When it is outputting text that is a matched part of a subject string,
1900            it does the same, unless a different locale has been set for the match
1901            (using the /L modifier). In this case, it uses isprint() to decide.
1902    
1903     4. Fixed a major bug that caused incorrect computation of the amount of memory
1904        required for a compiled pattern when options that changed within the
1905        pattern affected the logic of the preliminary scan that determines the
1906        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1907        that the computed length was too small. The symptoms of this bug were
1908        either the PCRE error "internal error: code overflow" from pcre_compile(),
1909        or a glibc crash with a message such as "pcretest: free(): invalid next
1910        size (fast)". Examples of patterns that provoked this bug (shown in
1911        pcretest format) are:
1912    
1913          /(?-x: )/x
1914          /(?x)(?-x: \s*#\s*)/
1915          /((?i)[\x{c0}])/8
1916          /(?i:[\x{c0}])/8
1917    
1918        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1919        is now done differently.
1920    
1921     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1922        wrapper classes; (b) implement a new function in the C++ scanner that is
1923        more efficient than the old way of doing things because it avoids levels of
1924        recursion in the regex matching; (c) add a paragraph to the documentation
1925        for the FullMatch() function.
1926    
1927     6. The escape sequence \n was being treated as whatever was defined as
1928        "newline". Not only was this contrary to the documentation, which states
1929        that \n is character 10 (hex 0A), but it also went horribly wrong when
1930        "newline" was defined as CRLF. This has been fixed.
1931    
1932     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1933        was being set to -1 for the "end of line" case (supposedly a value that no
1934        character can have). Though this value is never used (the check for end of
1935        line is "zero bytes in current character"), it caused compiler complaints.
1936        I've changed it to 0xffffffff.
1937    
1938     8. In pcre_version.c, the version string was being built by a sequence of
1939        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1940        string (as it is for production releases) called a macro with an empty
1941        argument. The C standard says the result of this is undefined. The gcc
1942        compiler treats it as an empty string (which was what was wanted) but it is
1943        reported that Visual C gives an error. The source has been hacked around to
1944        avoid this problem.
1945    
1946     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1947        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1948        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1949        of them did).
1950    
1951    10. Originally, pcretest opened its input and output without "b"; then I was
1952        told that "b" was needed in some environments, so it was added for release
1953        5.0 to both the input and output. (It makes no difference on Unix-like
1954        systems.) Later I was told that it is wrong for the input on Windows. I've
1955        now abstracted the modes into two macros, to make it easier to fiddle with
1956        them, and removed "b" from the input mode under Windows.
1957    
1958    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1959    
1960    12. Added -help and --help to pcretest as an official way of being reminded
1961        of the options.
1962    
1963    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1964        and pcrecpp.cc because they annoy compilers at high warning levels.
1965    
1966    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1967    
1968    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1969        scripts are not C programs :-) and which was not noticed because it works
1970        on Linux.
1971    
1972    16. pcretest is supposed to handle any length of pattern and data line (as one
1973        line or as a continued sequence of lines) by extending its input buffer if
1974        necessary. This feature was broken for very long pattern lines, leading to
1975        a string of junk being passed to pcre_compile() if the pattern was longer
1976        than about 50K.
1977    
1978    17. I have done a major re-factoring of the way pcre_compile() computes the
1979        amount of memory needed for a compiled pattern. Previously, there was code
1980        that made a preliminary scan of the pattern in order to do this. That was
1981        OK when PCRE was new, but as the facilities have expanded, it has become
1982        harder and harder to keep it in step with the real compile phase, and there
1983        have been a number of bugs (see for example, 4 above). I have now found a
1984        cunning way of running the real compile function in a "fake" mode that
1985        enables it to compute how much memory it would need, while actually only
1986        ever using a few hundred bytes of working memory and without too many
1987        tests of the mode. This should make future maintenance and development
1988        easier. A side effect of this work is that the limit of 200 on the nesting
1989        depth of parentheses has been removed (though this was never a serious
1990        limitation, I suspect). However, there is a downside: pcre_compile() now
1991        runs more slowly than before (30% or more, depending on the pattern). I
1992        hope this isn't a big issue. There is no effect on runtime performance.
1993    
1994    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1995        newline (only possible for the last line of a file) and it was a
1996        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1997    
1998    19. Added additional timing features to pcretest. (1) The -tm option now times
1999        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2000        separate command line item, by a number that specifies the number of
2001        repeats to use when timing. The default is 50000; this gives better
2002        precision, but takes uncomfortably long for very large patterns.
2003    
2004    20. Extended pcre_study() to be more clever in cases where a branch of a
2005        subpattern has no definite first character. For example, (a*|b*)[cd] would
2006        previously give no result from pcre_study(). Now it recognizes that the
2007        first character must be a, b, c, or d.
2008    
2009    21. There was an incorrect error "recursive call could loop indefinitely" if
2010        a subpattern (or the entire pattern) that was being tested for matching an
2011        empty string contained only one non-empty item after a nested subpattern.
2012        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2013        incorrectly, because the \d was being skipped in the check.
2014    
2015    22. The pcretest program now has a new pattern option /B and a command line
2016        option -b, which is equivalent to adding /B to every pattern. This causes
2017        it to show the compiled bytecode, without the additional information that
2018        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2019        is the same as /B/I).
2020    
2021    23. A new optimization is now able automatically to treat some sequences such
2022        as a*b as a*+b. More specifically, if something simple (such as a character
2023        or a simple class like \d) has an unlimited quantifier, and is followed by
2024        something that cannot possibly match the quantified thing, the quantifier
2025        is automatically "possessified".
2026    
2027    24. A recursive reference to a subpattern whose number was greater than 39
2028        went wrong under certain circumstances in UTF-8 mode. This bug could also
2029        have affected the operation of pcre_study().
2030    
2031    25. Realized that a little bit of performance could be had by replacing
2032        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2033    
2034    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2035    
2036    27. Possessive quantifiers such as a++ were previously implemented by turning
2037        them into atomic groups such as ($>a+). Now they have their own opcodes,
2038        which improves performance. This includes the automatically created ones
2039        from 23 above.
2040    
2041    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2042        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2043        the first matched character to be a colon. This applied both to named and
2044        numbered groups.
2045    
2046    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2047    
2048    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2049        building PCRE on Windows easier, so I have included it in the distribution.
2050    
2051    31. There is now a check in pcretest against a ridiculously large number being
2052        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2053        loop, the loop is abandoned.
2054    
2055    32. Forward references to subpatterns in conditions such as (?(2)...) where
2056        subpattern 2 is defined later cause pcre_compile() to search forwards in
2057        the pattern for the relevant set of parentheses. This search went wrong
2058        when there were unescaped parentheses in a character class, parentheses
2059        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2060    
2061    33. "Subroutine" calls and backreferences were previously restricted to
2062        referencing subpatterns earlier in the regex. This restriction has now
2063        been removed.
2064    
2065    34. Added a number of extra features that are going to be in Perl 5.10. On the
2066        whole, these are just syntactic alternatives for features that PCRE had
2067        previously implemented using the Python syntax or my own invention. The
2068        other formats are all retained for compatibility.
2069    
2070        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2071            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2072            also .NET compatible.
2073    
2074        (b) A recursion or subroutine call to a named group can now be defined as
2075            (?&name) as well as (?P>name).
2076    
2077        (c) A backreference to a named group can now be defined as \k<name> or
2078            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2079            5.10, are also .NET compatible.
2080    
2081        (d) A conditional reference to a named group can now use the syntax
2082            (?(<name>) or (?('name') as well as (?(name).
2083    
2084        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2085            groups (named and numbered) that are never evaluated inline, but can be
2086            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2087            is always false. There may be only one alternative in such a group.
2088    
2089        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2090            as the simple (?(R). The condition is true only if the most recent
2091            recursion is that of the given number or name. It does not search out
2092            through the entire recursion stack.
2093    
2094        (g) The escape \gN or \g{N} has been added, where N is a positive or
2095            negative number, specifying an absolute or relative reference.
2096    
2097    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2098        some "unreachable code" warnings.
2099    
2100    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2101        things, this adds five new scripts.
2102    
2103    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2104        There were also incompatibilities regarding the handling of \Q..\E inside
2105        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2106        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2107    
2108    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2109        matches an empty string, and forcibly breaks the loop. There were bugs in
2110        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2111        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2112        separate and independent bugs (that affected different cases) have been
2113        fixed.
2114    
2115    39. Refactored the code to abolish the use of different opcodes for small
2116        capturing bracket numbers. This is a tidy that I avoided doing when I
2117        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2118        The new approach is not only tidier, it makes it possible to reduce the
2119        memory needed to fix the previous bug (38).
2120    
2121    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2122        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2123        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2124        mode.
2125    
2126    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2127        report.
2128    
2129    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2130        copy construction and assignment in the C++ wrapper.
2131    
2132    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2133        couple of bugs that could have given wrong results in the "--newline=crlf"
2134        case.
2135    
2136    44. Added a number of casts and did some reorganization of signed/unsigned int
2137        variables following suggestions from Dair Grant. Also renamed the variable
2138        "this" as "item" because it is a C++ keyword.
2139    
2140    45. Arranged for dftables to add
2141    
2142          #include "pcre_internal.h"
2143    
2144        to pcre_chartables.c because without it, gcc 4.x may remove the array
2145        definition from the final binary if PCRE is built into a static library and
2146        dead code stripping is activated.
2147    
2148    46. For an unanchored pattern, if a match attempt fails at the start of a
2149        newline sequence, and the newline setting is CRLF or ANY, and the next two
2150        characters are CRLF, advance by two characters instead of one.
2151    
2152    
2153    Version 6.7 04-Jul-06
2154    ---------------------
2155    
2156     1. In order to handle tests when input lines are enormously long, pcretest has
2157        been re-factored so that it automatically extends its buffers when
2158        necessary. The code is crude, but this _is_ just a test program. The
2159        default size has been increased from 32K to 50K.
2160    
2161     2. The code in pcre_study() was using the value of the re argument before
2162        testing it for NULL. (Of course, in any sensible call of the function, it
2163        won't be NULL.)
2164    
2165     3. The memmove() emulation function in pcre_internal.h, which is used on
2166        systems that lack both memmove() and bcopy() - that is, hardly ever -
2167        was missing a "static" storage class specifier.
2168    
2169     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2170        containing an extended class (one that cannot be represented by a bitmap
2171        because it contains high-valued characters or Unicode property items, e.g.
2172        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2173        pattern, but PCRE should not loop if you do not (it no longer does).
2174        [Detail: two cases were found: (a) a repeated subpattern containing an
2175        extended class; (b) a recursive reference to a subpattern that followed a
2176        previous extended class. It wasn't skipping over the extended class
2177        correctly when UTF-8 mode was not set.]
2178    
2179     5. A negated single-character class was not being recognized as fixed-length
2180        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2181        compile error "lookbehind assertion is not fixed length".
2182    
2183     6. The RunPerlTest auxiliary script was showing an unexpected difference
2184        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2185        write a Perl script that can interpret lines of an input file either as
2186        byte characters or as UTF-8, which is what "perltest" was being required to
2187        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2188        can't do is switch easily at run time between having the "use utf8;" pragma
2189        or not. In the end, I fudged it by using the RunPerlTest script to insert
2190        "use utf8;" explicitly for the UTF-8 tests.
2191    
2192     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2193        the end of the subject string, contrary to the documentation and to what
2194        Perl does. This was true of both matching functions. Now it matches only at
2195        the start of the subject and immediately after *internal* newlines.
2196    
2197     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2198        a pointer to an int instead of a pointer to an unsigned long int. This
2199        caused problems on 64-bit systems.
2200    
2201     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2202        instance of the 'standard' template library not being so standard".
2203    
2204    10. There was no check on the number of named subpatterns nor the maximum
2205        length of a subpattern name. The product of these values is used to compute
2206        the size of the memory block for a compiled pattern. By supplying a very
2207        long subpattern name and a large number of named subpatterns, the size
2208        computation could be caused to overflow. This is now prevented by limiting
2209        the length of names to 32 characters, and the number of named subpatterns
2210        to 10,000.
2211    
2212    11. Subpatterns that are repeated with specific counts have to be replicated in
2213        the compiled pattern. The size of memory for this was computed from the
2214        length of the subpattern and the repeat count. The latter is limited to
2215        65535, but there was no limit on the former, meaning that integer overflow
2216        could in principle occur. The compiled length of a repeated subpattern is
2217        now limited to 30,000 bytes in order to prevent this.
2218    
2219    12. Added the optional facility to have named substrings with the same name.
2220    
2221    13. Added the ability to use a named substring as a condition, using the
2222        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2223        are numbers (not recommended). Forward references are permitted.
2224    
2225    14. Added forward references in named backreferences (if you see what I mean).
2226    
2227    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2228        pattern could run off the end of the subject. For example, the pattern
2229        "(?s)(.{1,5})"8 did this with the subject "ab".
2230    
2231    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2232        PCRE_CASELESS was set when matching characters that were quantified with ?
2233        or *.
2234    
2235    17. A character class other than a single negated character that had a minimum
2236        but no maximum quantifier - for example [ab]{6,} - was not handled
2237        correctly by pce_dfa_exec(). It would match only one character.
2238    
2239    18. A valid (though odd) pattern that looked like a POSIX character
2240        class but used an invalid character after [ (for example [[,abc,]]) caused
2241        pcre_compile() to give the error "Failed: internal error: code overflow" or
2242        in some cases to crash with a glibc free() error. This could even happen if
2243        the pattern terminated after [[ but there just happened to be a sequence of
2244        letters, a binary zero, and a closing ] in the memory that followed.
2245    
2246    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2247        over the years. Originally (before any Unicode support), just the bottom 8
2248        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2249        output from "man perlunicode" includes this:
2250    
2251          The regular expression compiler produces polymorphic opcodes.  That
2252          is, the pattern adapts to the data and automatically switches to
2253          the Unicode character scheme when presented with Unicode data--or
2254          instead uses a traditional byte scheme when presented with byte
2255          data.
2256    
2257        Sadly, a wide octal escape does not cause a switch, and in a string with
2258        no other multibyte characters, these octal escapes are treated as before.
2259        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2260        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2261        Unicode string.
2262    
2263        I have not perpetrated such confusion in PCRE. Up till now, it took just
2264        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2265        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2266        translate to the appropriate multibyte character.
2267    
2268    29. Applied some refactoring to reduce the number of warnings from Microsoft
2269        and Borland compilers. This has included removing the fudge introduced
2270        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2271        a warning about an unused variable.
2272    
2273    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2274        characters since release 4.0, because Perl (from release 5.004) does not.
2275        [Or at least, is documented not to: some releases seem to be in conflict
2276        with the documentation.] However, when a pattern was studied with
2277        pcre_study() and all its branches started with \s, PCRE still included VT
2278        as a possible starting character. Of course, this did no harm; it just
2279        caused an unnecessary match attempt.
2280    
2281    22. Removed a now-redundant internal flag bit that recorded the fact that case
2282        dependency changed within the pattern. This was once needed for "required
2283        byte" processing, but is no longer used. This recovers a now-scarce options
2284        bit. Also moved the least significant internal flag bit to the most-
2285        significant bit of the word, which was not previously used (hangover from
2286        the days when it was an int rather than a uint) to free up another bit for
2287        the future.
2288    
2289    23. Added support for CRLF line endings as well as CR and LF. As well as the
2290        default being selectable at build time, it can now be changed at runtime
2291        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2292        specify that it is scanning data with non-default line endings.
2293    
2294    24. Changed the definition of CXXLINK to make it agree with the definition of
2295        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2296    
2297    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2298        recursions. This makes a big different to stack usage for some patterns.
2299    
2300    26. If a subpattern containing a named recursion or subroutine reference such
2301        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2302        the space required for the compiled pattern went wrong and gave too small a
2303        value. Depending on the environment, this could lead to "Failed: internal
2304        error: code overflow at offset 49" or "glibc detected double free or
2305        corruption" errors.
2306    
2307    27. Applied patches from Google (a) to support the new newline modes and (b) to
2308        advance over multibyte UTF-8 characters in GlobalReplace.
2309    
2310    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2311        difference for some implementation of PCRE in some Windows version.
2312    
2313    29. Added some extra testing facilities to pcretest:
2314    
2315        \q<number>   in a data line sets the "match limit" value
2316        \Q<number>   in a data line sets the "match recursion limt" value
2317        -S <number>  sets the stack size, where <number> is in megabytes
2318    
2319        The -S option isn't available for Windows.
2320    
2321    
2322    Version 6.6 06-Feb-06
2323    ---------------------
2324    
2325     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2326        in pcreposix.h. I have copied the definition from pcre.h.
2327    
2328     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2329        because pcre.h is no longer a built file.
2330    
2331     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2332        not normally included in the compiled code.
2333    
2334    
2335    Version 6.5 01-Feb-06
2336    ---------------------
2337    
2338     1. When using the partial match feature with pcre_dfa_exec(), it was not
2339        anchoring the second and subsequent partial matches at the new starting
2340        point. This could lead to incorrect results. For example, with the pattern
2341        /1234/, partially matching against "123" and then "a4" gave a match.
2342    
2343     2. Changes to pcregrep:
2344    
2345        (a) All non-match returns from pcre_exec() were being treated as failures
2346            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2347            error message is output. Some extra information is given for the
2348            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2349            probably the only errors that are likely to be caused by users (by
2350            specifying a regex that has nested indefinite repeats, for instance).
2351            If there are more than 20 of these errors, pcregrep is abandoned.
2352    
2353        (b) A binary zero was treated as data while matching, but terminated the
2354            output line if it was written out. This has been fixed: binary zeroes
2355            are now no different to any other data bytes.
2356    
2357        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2358            used to set a locale for matching. The --locale=xxxx long option has
2359            been added (no short equivalent) to specify a locale explicitly on the
2360            pcregrep command, overriding the environment variables.
2361    
2362        (d) When -B was used with -n, some line numbers in the output were one less
2363            than they should have been.
2364    
2365        (e) Added the -o (--only-matching) option.
2366    
2367        (f) If -A or -C was used with -c (count only), some lines of context were
2368            accidentally printed for the final match.
2369    
2370        (g) Added the -H (--with-filename) option.
2371    
2372        (h) The combination of options -rh failed to suppress file names for files
2373            that were found from directory arguments.
2374    
2375        (i) Added the -D (--devices) and -d (--directories) options.
2376    
2377        (j) Added the -F (--fixed-strings) option.
2378    
2379        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2380    
2381        (l) Added the --colo(u)r option.
2382    
2383        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2384            is not present by default.
2385    
2386     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2387        items such as (?R) or (?1), when the recursion could match a number of
2388        alternatives. If it matched one of the alternatives, but subsequently,
2389        outside the recursion, there was a failure, the code tried to back up into
2390        the recursion. However, because of the way PCRE is implemented, this is not
2391        possible, and the result was an incorrect result from the match.
2392    
2393        In order to prevent this happening, the specification of recursion has
2394        been changed so that all such subpatterns are automatically treated as
2395        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2396    
2397     4. I had overlooked the fact that, in some locales, there are characters for
2398        which isalpha() is true but neither isupper() nor islower() are true. In
2399        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2400        and ordfeminine) are like this. This affected the treatment of \w and \W
2401        when they appeared in character classes, but not when they appeared outside
2402        a character class. The bit map for "word" characters is now created
2403        separately from the results of isalnum() instead of just taking it from the
2404        upper, lower, and digit maps. (Plus the underscore character, of course.)
2405    
2406     5. The above bug also affected the handling of POSIX character classes such as
2407        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2408        permanent tables. Instead, the bit maps for such a class were previously
2409        created as the appropriate unions of the upper, lower, and digit bitmaps.
2410        Now they are created by subtraction from the [[:word:]] class, which has
2411        its own bitmap.
2412    
2413     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2414        It is created by subtracting the vertical space characters (\x09, \x0a,
2415        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2416        subtraction was done in the overall bitmap for a character class, meaning
2417        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2418        be recognized. This bug has been fixed.
2419    
2420     7. Patches from the folks at Google:
2421    
2422          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2423          real life, but is still worth protecting against".
2424    
2425          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2426          regular expressions".
2427    
2428          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2429          have it.
2430    
2431          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2432          "configure" and the latter not, in order to fix a problem somebody had
2433          with compiling the Arg class on HP-UX.
2434    
2435          (e) Improve the error-handling of the C++ wrapper a little bit.
2436    
2437          (f) New tests for checking recursion limiting.
2438    
2439     8. The pcre_memmove() function, which is used only if the environment does not
2440        have a standard memmove() function (and is therefore rarely compiled),
2441        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2442        returning a result (though PCRE never actually uses the result).
2443    
2444     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2445        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2446        returned instead of calling malloc() with an overflowing number that would
2447        most likely cause subsequent chaos.
2448    
2449    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2450    
2451    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2452        with this option is matched, the nmatch and pmatch options of regexec() are
2453        ignored.
2454    
2455    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2456        provided in case anyone wants to the the POSIX interface with UTF-8
2457        strings.
2458    
2459    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2460        C++ linking (needed for some HP-UX environments).
2461    
2462    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2463        (unused parameter) and in the pcre_printint() function (omitted "default"
2464        switch label when the default is to do nothing).
2465    
2466    15. Added some code to make it possible, when PCRE is compiled as a C++
2467        library, to replace subject pointers for pcre_exec() with a smart pointer
2468        class, thus making it possible to process discontinuous strings.
2469    
2470    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2471        much the same function. They were added by different people who were trying
2472        to make PCRE easy to compile on non-Unix systems. It has been suggested
2473        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2474        for compiling on Windows systems. I have therefore replaced it with
2475        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2476        defaults to "extern" for C or "extern C" for C++, which works fine on
2477        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2478        SCOPE with something explicit in config.h. In addition:
2479    
2480        (a) pcreposix.h still had just "extern" instead of either of these macros;
2481            I have replaced it with PCRE_DATA_SCOPE.
2482    
2483        (b) Functions such as _pcre_xclass(), which are internal to the library,
2484            but external in the C sense, all had PCRE_EXPORT in their definitions.
2485            This is apparently wrong for the Windows case, so I have removed it.
2486            (It makes no difference on Unix-like systems.)
2487    
2488    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2489        of recursive calls to match(). This is different to MATCH_LIMIT because
2490        that limits the total number of calls to match(), not all of which increase
2491        the depth of recursion. Limiting the recursion depth limits the amount of
2492        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2493        when PCRE is compiled, and changed at run time. A patch from Google adds
2494        this functionality to the C++ interface.
2495    
2496    18. Changes to the handling of Unicode character properties:
2497    
2498        (a) Updated the table to Unicode 4.1.0.
2499    
2500        (b) Recognize characters that are not in the table as "Cn" (undefined).
2501    
2502        (c) I revised the way the table is implemented to a much improved format
2503            which includes recognition of ranges. It now supports the ranges that
2504            are defined in UnicodeData.txt, and it also amalgamates other
2505            characters into ranges. This has reduced the number of entries in the
2506            table from around 16,000 to around 3,000, thus reducing its size
2507            considerably. I realized I did not need to use a tree structure after
2508            all - a binary chop search is just as efficient. Having reduced the
2509            number of entries, I extended their size from 6 bytes to 8 bytes to
2510            allow for more data.
2511    
2512        (d) Added support for Unicode script names via properties such as \p{Han}.
2513    
2514    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2515        matching that character.
2516    
2517    20. When matching a repeated Unicode property with a minimum greater than zero,
2518        (for example \pL{2,}), PCRE could look past the end of the subject if it
2519        reached it while seeking the minimum number of characters. This could
2520        happen only if some of the characters were more than one byte long, because
2521        there is a check for at least the minimum number of bytes.
2522    
2523    21. Refactored the implementation of \p and \P so as to be more general, to
2524        allow for more different types of property in future. This has changed the
2525        compiled form incompatibly. Anybody with saved compiled patterns that use
2526        \p or \P will have to recompile them.
2527    
2528    22. Added "Any" and "L&" to the supported property types.
2529    
2530    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2531        but give a compile time error if the value is greater than 0xff.
2532    
2533    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2534        accidentally not being installed or uninstalled.
2535    
2536    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2537        made were to insert the current release number. This seemed silly, because
2538        it made things harder for people building PCRE on systems that don't run
2539        "configure". I have turned pcre.h into a distributed file, no longer built
2540        by "configure", with the version identification directly included. There is
2541        no longer a pcre.h.in file.
2542    
2543        However, this change necessitated a change to the pcre-config script as
2544        well. It is built from pcre-config.in, and one of the substitutions was the
2545        release number. I have updated configure.ac so that ./configure now finds
2546        the release number by grepping pcre.h.
2547    
2548    26. Added the ability to run the tests under valgrind.
2549    
2550    
2551    Version 6.4 05-Sep-05
2552    ---------------------
2553    
2554     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2555        "--" to be printed when multiple files were scanned, even when none of the
2556        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2557        consider it to be a bug, and have restored the previous behaviour.
2558    
2559     2. A couple of code tidies to get rid of compiler warnings.
2560    
2561     3. The pcretest program used to cheat by referring to symbols in the library
2562        whose names begin with _pcre_. These are internal symbols that are not
2563        really supposed to be visible externally, and in some environments it is
2564        possible to suppress them. The cheating is now confined to including
2565        certain files from the library's source, which is a bit cleaner.
2566    
2567     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2568        file's purpose clearer.
2569    
2570     5. Reorganized pcre_ucp_findchar().
2571    
2572    
2573    Version 6.3 15-Aug-05
2574    ---------------------
2575    
2576     1. The file libpcre.pc.in did not have general read permission in the tarball.
2577    
2578     2. There were some problems when building without C++ support:
2579    
2580        (a) If C++ support was not built, "make install" and "make test" still
2581            tried to test it.
2582    
2583        (b) There were problems when the value of CXX was explicitly set. Some
2584            changes have been made to try to fix these, and ...
2585    
2586        (c) --disable-cpp can now be used to explicitly disable C++ support.
2587    
2588        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2589            backslash in a target when C++ was disabled. This confuses some
2590            versions of "make", apparently. Using an intermediate variable solves
2591            this. (Same for CPP_LOBJ.)
2592    
2593     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2594        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2595        necessary on certain architectures.
2596    
2597     4. Added a setting of -export-symbols-regex to the link command to remove
2598        those symbols that are exported in the C sense, but actually are local
2599        within the library, and not documented. Their names all begin with
2600        "_pcre_". This is not a perfect job, because (a) we have to except some
2601        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2602        available (and never for static libraries). I have made a note to try to
2603        find a way round (a) in the future.
2604    
2605    
2606    Version 6.2 01-Aug-05
2607    ---------------------
2608    
2609     1. There was no test for integer overflow of quantifier values. A construction
2610        such as {1111111111111111} would give undefined results. What is worse, if
2611        a minimum quantifier for a parenthesized subpattern overflowed and became
2612        negative, the calculation of the memory size went wrong. This could have
2613        led to memory overwriting.
2614    
2615     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2616    
2617     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2618        operating environments where this matters.
2619    
2620     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2621        PCRE options from within the C++ wrapper.
2622    
2623     5. Named capturing subpatterns were not being correctly counted when a pattern
2624        was compiled. This caused two problems: (a) If there were more than 100
2625        such subpatterns, the calculation of the memory needed for the whole
2626        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2627        back references of the form \12, where the number was greater than 9, were
2628        not recognized as back references, even though there were sufficient
2629        previous subpatterns.
2630    
2631     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2632        versions of gcc, e.g. 2.95.4.
2633    
2634    
2635    Version 6.1 21-Jun-05
2636    ---------------------
2637    
2638     1. There was one reference to the variable "posix" in pcretest.c that was not
2639        surrounded by "#if !defined NOPOSIX".
2640    
2641     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2642        the cross-check on the old pcre_info() function, for the benefit of the
2643        cut-down version of PCRE that is currently imported into Exim.
2644    
2645     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2646        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2647        patterns that start (?i) but I don't think that matters. The use of (?i) is
2648        just an example; this all applies to the other options as well.
2649    
2650     4. Since libtool seems to echo the compile commands it is issuing, the output
2651        from "make" can be reduced a bit by putting "@" in front of each libtool
2652        compile command.
2653    
2654     5. Patch from the folks at Google for configure.in to be a bit more thorough
2655        in checking for a suitable C++ installation before trying to compile the
2656        C++ stuff. This should fix a reported problem when a compiler was present,
2657        but no suitable headers.
2658    
2659     6. The man pages all had just "PCRE" as their title. I have changed them to
2660        be the relevant file name. I have also arranged that these names are
2661        retained in the file doc/pcre.txt, which is a concatenation in text format
2662        of all the man pages except the little individual ones for each function.
2663    
2664     7. The NON-UNIX-USE file had not been updated for the different set of source
2665        files that come with release 6. I also added a few comments about the C++
2666        wrapper.
2667    
2668    
2669    Version 6.0 07-Jun-05
2670    ---------------------
2671    
2672     1. Some minor internal re-organization to help with my DFA experiments.
2673    
2674     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2675        didn't matter for the library itself when fully configured, but did matter
2676        when compiling without UCP support, or within Exim, where the ucp files are
2677        not imported.
2678    
2679     3. Refactoring of the library code to split up the various functions into
2680        different source modules. The addition of the new DFA matching code (see
2681        below) to a single monolithic source would have made it really too
2682        unwieldy, quite apart from causing all the code to be include in a
2683        statically linked application, when only some functions are used. This is
2684        relevant even without the DFA addition now that patterns can be compiled in
2685        one application and matched in another.
2686    
2687        The downside of splitting up is that there have to be some external
2688        functions and data tables that are used internally in different modules of
2689        the library but which are not part of the API. These have all had their
2690        names changed to start with "_pcre_" so that they are unlikely to clash
2691        with other external names.
2692    
2693     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2694        a different (DFA) algorithm. Although it is slower than the original
2695        function, it does have some advantages for certain types of matching
2696        problem.
2697    
2698     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2699        including restarting after a partial match.
2700    
2701     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2702        defined when compiling for Windows was sent to me. I have put it into the
2703        code, though I have no means of testing or verifying it.
2704    
2705     7. Added the pcre_refcount() auxiliary function.
2706    
2707     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2708        match before or at the first newline in the subject string. In pcretest,
2709        the /f option on a pattern can be used to set this.
2710    
2711     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2712        would behave wrongly. This has been present in PCRE since release 4.0.
2713    
2714    10. A number of changes to the pcregrep command:
2715    
2716        (a) Refactored how -x works; insert ^(...)$ instead of setting
2717            PCRE_ANCHORED and checking the length, in preparation for adding
2718            something similar for -w.
2719    
2720        (b) Added the -w (match as a word) option.
2721    
2722        (c) Refactored the way lines are read and buffered so as to have more
2723            than one at a time available.
2724    
2725        (d) Implemented a pcregrep test script.
2726    
2727        (e) Added the -M (multiline match) option. This allows patterns to match
2728            over several lines of the subject. The buffering ensures that at least
2729            8K, or the rest of the document (whichever is the shorter) is available
2730            for matching (and similarly the previous 8K for lookbehind assertions).
2731    
2732        (f) Changed the --help output so that it now says
2733    
2734              -w, --word-regex(p)
2735    
2736            instead of two lines, one with "regex" and the other with "regexp"
2737            because that confused at least one person since the short forms are the
2738            same. (This required a bit of code, as the output is generated
2739            automatically from a table. It wasn't just a text change.)
2740    
2741        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2742            option but starts with a hyphen. Could be a pattern or a path name
2743            starting with a hyphen, for instance.
2744    
2745        (h) "-" can be given as a file name to represent stdin.
2746    
2747        (i) When file names are being printed, "(standard input)" is used for
2748            the standard input, for compatibility with GNU grep. Previously
2749            "<stdin>" was used.
2750    
2751        (j) The option --label=xxx can be used to supply a name to be used for
2752            stdin when file names are being printed. There is no short form.
2753    
2754        (k) Re-factored the options decoding logic because we are going to add
2755            two more options that take data. Such options can now be given in four
2756            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2757    
2758        (l) Added the -A, -B, and -C options for requesting that lines of context
2759            around matches be printed.
2760    
2761        (m) Added the -L option to print the names of files that do not contain
2762            any matching lines, that is, the complement of -l.
2763    
2764        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2765            continue to scan other files.
2766    
2767        (o) The -s option was incorrectly implemented. For compatibility with other
2768            greps, it now suppresses the error message for a non-existent or non-
2769            accessible file (but not the return code). There is a new option called
2770            -q that suppresses the output of matching lines, which was what -s was
2771            previously doing.
2772    
2773        (p) Added --include and --exclude options to specify files for inclusion
2774            and exclusion when recursing.
2775    
2776    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2777        Hopefully, it now does.
2778    
2779    12. Missing cast in pcre_study().
2780    
2781    13. Added an "uninstall" target to the makefile.
2782    
2783    14. Replaced "extern" in the function prototypes in Makefile.in with
2784        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2785        world, but is set differently for Windows.
2786    
2787    15. Added a second compiling function called pcre_compile2(). The only
2788        difference is that it has an extra argument, which is a pointer to an
2789        integer error code. When there is a compile-time failure, this is set
2790        non-zero, in addition to the error test pointer being set to point to an
2791        error message. The new argument may be NULL if no error number is required
2792        (but then you may as well call pcre_compile(), which is now just a
2793        wrapper). This facility is provided because some applications need a
2794        numeric error indication, but it has also enabled me to tidy up the way
2795        compile-time errors are handled in the POSIX wrapper.
2796    
2797    16. Added VPATH=.libs to the makefile; this should help when building with one
2798        prefix path and installing with another. (Or so I'm told by someone who
2799        knows more about this stuff than I do.)
2800    
2801    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2802        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2803        match everything, including newlines. This is not POSIX-compatible, but
2804        somebody wanted the feature. From pcretest it can be activated by using
2805        both the P and the s flags.
2806    
2807    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2808    
2809    19. libpcre.pc was being incorrectly installed as executable.
2810    
2811    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2812        it now also looks for '\r' so that it will work unmodified on Windows.
2813    
2814    21. Added Google's contributed C++ wrapper to the distribution.
2815    
2816    22. Added some untidy missing memory free() calls in pcretest, to keep
2817        Electric Fence happy when testing.
2818    
2819    
2820    
2821    Version 5.0 13-Sep-04
2822    ---------------------
2823    
2824     1. Internal change: literal characters are no longer packed up into items
2825        containing multiple characters in a single byte-string. Each character
2826        is now matched using a separate opcode. However, there may be more than one
2827        byte in the character in UTF-8 mode.
2828    
2829     2. The pcre_callout_block structure has two new fields: pattern_position and
2830        next_item_length. These contain the offset in the pattern to the next match
2831        item, and its length, respectively.
2832    
2833     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2834        insertion of callouts before each pattern item. Added the /C option to
2835        pcretest to make use of this.
2836    
2837     4. On the advice of a Windows user, the lines
2838    
2839          #if defined(_WIN32) || defined(WIN32)
2840          _setmode( _fileno( stdout ), 0x8000 );
2841          #endif  /* defined(_WIN32) || defined(WIN32) */
2842    
2843        have been added to the source of pcretest. This apparently does useful
2844        magic in relation to line terminators.
2845    
2846     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2847        for the benefit of those environments where the "b" makes a difference.
2848    
2849     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2850        to know about it. I have put a hack into configure.in that adds in code
2851        to set GCC=yes if CC=icc. This seems to end up at a point in the
2852        generated configure script that is early enough to affect the setting of
2853        compiler options, which is what is needed, but I have no means of testing
2854        whether it really works. (The user who reported this had patched the
2855        generated configure script, which of course I cannot do.)
2856    
2857        LATER: After change 22 below (new libtool files), the configure script
2858        seems to know about icc (and also ecc). Therefore, I have commented out
2859        this hack in configure.in.
2860    
2861     7. Added support for pkg-config (2 patches were sent in).
2862    
2863     8. Negated POSIX character classes that used a combination of internal tables
2864        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2865        [[:^ascii]]. Typically, they would match almost any characters. The other
2866        POSIX classes were not broken in this way.
2867    
2868     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2869        to find the match, as PCRE was deluded into thinking that the match had to
2870        start at the start point or following a newline. The same bug applied to
2871        patterns with negative forward assertions or any backward assertions
2872        preceding ".*" at the start, unless the pattern required a fixed first
2873        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2874    
2875    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2876        starting at the last subject character, bytes beyond the end of the subject
2877        string were read.
2878    
2879    11. Renamed the variable "class" as "classbits" to make life easier for C++
2880        users. (Previously there was a macro definition, but it apparently wasn't
2881        enough.)
2882    
2883    12. Added the new field "tables" to the extra data so that tables can be passed
2884        in at exec time, or the internal tables can be re-selected. This allows
2885        a compiled regex to be saved and re-used at a later time by a different
2886        program that might have everything at different addresses.
2887    
2888    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2889        -R library as well as a -L library.
2890    
2891    14. The debugging options of pcretest (-d on the command line or D on a
2892        pattern) showed incorrect output for anything following an extended class
2893        that contained multibyte characters and which was followed by a quantifier.
2894    
2895    15. Added optional support for general category Unicode character properties
2896        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2897        support. It adds about 90K to the size of the library. The meanings of the
2898        inbuilt class escapes such as \d and \s have NOT been changed.
2899    
2900    16. Updated pcredemo.c to include calls to free() to release the memory for the
2901        compiled pattern.
2902    
2903    17. The generated file chartables.c was being created in the source directory
2904        instead of in the building directory. This caused the build to fail if the
2905        source directory was different from the building directory, and was
2906        read-only.
2907    
2908    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2909        file. No doubt somebody will tell me if they don't make sense... Also added
2910        Dan Mooney's comments about building on OpenVMS.
2911    
2912    19. Added support for partial matching via the PCRE_PARTIAL option for
2913        pcre_exec() and the \P data escape in pcretest.
2914    
2915    20. Extended pcretest with 3 new pattern features:
2916    
2917        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2918              write the compiled pattern to the file whose name is "rest-of-line".
2919              This is a straight binary dump of the data, with the saved pointer to
2920              the character tables forced to be NULL. The study data, if any, is
2921              written too. After writing, pcretest reads a new pattern.
2922    
2923        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2924              compiled pattern from the given file. There must not be any
2925              occurrences of "<" in the file name (pretty unlikely); if there are,
2926              pcretest will instead treat the initial "<" as a pattern delimiter.
2927              After reading in the pattern, pcretest goes on to read data lines as
2928              usual.
2929    
2930        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2931              and 16-bit fields in a compiled pattern, to simulate a pattern that
2932              was compiled on a host of opposite endianness.
2933    
2934    21. The pcre-exec() function can now cope with patterns that were compiled on
2935        hosts of opposite endianness, with this restriction:
2936    
2937          As for any compiled expression that is saved and used later, the tables
2938          pointer field cannot be preserved; the extra_data field in the arguments
2939          to pcre_exec() should be used to pass in a tables address if a value
2940          other than the default internal tables were used at compile time.
2941    
2942    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2943        now diagnosed as an error. Previously, most of the time, a negative number
2944        would have been treated as zero, but if in addition "ovector" was passed as
2945        NULL, a crash could occur.
2946    
2947    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2948        new versions from the libtool 1.5 distribution (the last one is a copy of
2949        a file called libtool.m4). This seems to have fixed the need to patch
2950        "configure" to support Darwin 1.3 (which I used to do). However, I still
2951        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2952        workstation).
2953    
2954    24. Changed the PCRE licence to be the more standard "BSD" licence.
2955    
2956    
2957    Version 4.5 01-Dec-03
2958    ---------------------
2959    
2960     1. There has been some re-arrangement of the code for the match() function so
2961        that it can be compiled in a version that does not call itself recursively.
2962        Instead, it keeps those local variables that need separate instances for
2963        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2964        needs to "recurse". Keeping track of where control must go is done by means
2965        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2966        hide most of the details from the main code, and operates only if
2967        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2968        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2969        operating.
2970    
2971        To make it easier for callers to provide specially tailored get/free
2972        functions for this usage, two new functions, pcre_stack_malloc, and
2973        pcre_stack_free, are used. They are always called in strict stacking order,
2974        and the size of block requested is always the same.
2975    
2976        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2977        PCRE has been compiled to use the stack or the heap for recursion. The
2978        -C option of pcretest uses this to show which version is compiled.
2979    
2980        A new data escape \S, is added to pcretest; it causes the amounts of store
2981        obtained and freed by both kinds of malloc/free at match time to be added
2982        to the output.
2983    
2984     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2985        what's available on my current Linux desktop machine.
2986    
2987     3. When matching a UTF-8 string, the test for a valid string at the start has
2988        been extended. If start_offset is not zero, PCRE now checks that it points
2989        to a byte that is the start of a UTF-8 character. If not, it returns
2990        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2991        this is necessary because there may be backward assertions in the pattern.
2992        When matching the same subject several times, it may save resources to use
2993        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2994    
2995     4. The code for checking the validity of UTF-8 strings has been tightened so
2996        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2997        containing "overlong sequences".
2998    
2999     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
3000        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
3001        should have been "&", but it just so happened that all the cases this let
3002        through by mistake were picked up later in the function.
3003    
3004     6. I had used a variable called "isblank" - this is a C99 function, causing
3005        some compilers to warn. To avoid this, I renamed it (as "blankclass").
3006    
3007     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
3008        prompting; (b) run "./pcretest /dev/null" at the start of the test script
3009        so the version is shown; (c) stop "make test" echoing "./RunTest".
3010    
3011     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
3012    
3013     9. The prototype for memmove() for systems that don't have it was using
3014        size_t, but the inclusion of the header that defines size_t was later. I've
3015        moved the #includes for the C headers earlier to avoid this.
3016    
3017    10. Added some adjustments to the code to make it easier to compiler on certain
3018        special systems:
3019    
3020          (a) Some "const" qualifiers were missing.
3021          (b) Added the macro EXPORT before all exported functions; by default this
3022              is defined to be empty.
3023          (c) Changed the dftables auxiliary program (that builds chartables.c) so
3024              that it reads its output file name as an argument instead of writing
3025              to the standard output and assuming this can be redirected.
3026    
3027    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
3028        class containing characters with values greater than 255, PCRE compilation
3029        went into a loop.
3030    
3031    12. A recursive reference to a subpattern that was within another subpattern
3032        that had a minimum quantifier of zero caused PCRE to crash. For example,
3033        (x(y(?2))z)? provoked this bug with a subject that got as far as the
3034        recursion. If the recursively-called subpattern itself had a zero repeat,
3035        that was OK.
3036    
3037    13. In pcretest, the buffer for reading a data line was set at 30K, but the
3038        buffer into which it was copied (for escape processing) was still set at
3039        1024, so long lines caused crashes.
3040    
3041    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
3042        "internal error: code overflow...". This applied to any character class
3043        that was followed by a possessive quantifier.
3044    
3045    15. Modified the Makefile to add libpcre.la as a prerequisite for
3046        libpcreposix.la because I was told this is needed for a parallel build to
3047        work.
3048    
3049    16. If a pattern that contained .* following optional items at the start was
3050        studied, the wrong optimizing data was generated, leading to matching
3051        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
3052        matching string must start with a or b or c. The correct conclusion for
3053        this pattern is that a match can start with any character.
3054    
3055    
3056    Version 4.4 13-Aug-03
3057    ---------------------
3058    
3059     1. In UTF-8 mode, a character class containing characters with values between
3060        127 and 255 was not handled correctly if the compiled pattern was studied.
3061        In fixing this, I have also improved the studying algorithm for such
3062        classes (slightly).
3063    
3064     2. Three internal functions had redundant arguments passed to them. Removal
3065        might give a very teeny performance improvement.
3066    
3067     3. Documentation bug: the value of the capture_top field in a callout is *one
3068        more than* the number of the hightest numbered captured substring.
3069    
3070     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3071        in incorrectly linking with a previously installed version. They now link
3072        explicitly with libpcre.la.
3073    
3074     5. configure.in no longer needs to recognize Cygwin specially.
3075    
3076     6. A problem in pcre.in for Windows platforms is fixed.
3077    
3078     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3079        pcretest, it used to include the size of the study block as part of its
3080        output. Unfortunately, the structure contains a field that has a different
3081        size on different hardware architectures. This meant that the tests that
3082        showed this size failed. As the block is currently always of a fixed size,
3083        this information isn't actually particularly useful in pcretest output, so
3084        I have just removed it.
3085    
3086     8. Three pre-processor statements accidentally did not start in column 1.
3087        Sadly, there are *still* compilers around that complain, even though
3088        standard C has not required this for well over a decade. Sigh.
3089    
3090     9. In pcretest, the code for checking callouts passed small integers in the
3091        callout_data field, which is a void * field. However, some picky compilers
3092        complained about the casts involved for this on 64-bit systems. Now
3093        pcretest passes the address of the small integer instead, which should get
3094        rid of the warnings.
3095    
3096    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3097        both compile and run time, and gives an error if an invalid UTF-8 sequence
3098        is found. There is a option for disabling this check in cases where the
3099        string is known to be correct and/or the maximum performance is wanted.
3100    
3101    11. In response to a bug report, I changed one line in Makefile.in from
3102    
3103            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3104        to
3105            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3106    
3107        to look similar to other lines, but I have no way of telling whether this
3108        is the right thing to do, as I do not use Windows. No doubt I'll get told
3109        if it's wrong...
3110    
3111    
3112    Version 4.3 21-May-03
3113    ---------------------
3114    
3115    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
3116       Makefile.
3117    
3118    2. Some refactoring to improve the quality of the code:
3119    
3120       (i)   The utf8_table... variables are now declared "const".
3121    
3122       (ii)  The code for \cx, which used the "case flipping" table to upper case
3123             lower case letters, now just substracts 32. This is ASCII-specific,
3124             but the whole concept of \cx is ASCII-specific, so it seems
3125             reasonable.
3126    
3127       (iii) PCRE was using its character types table to recognize decimal and
3128             hexadecimal digits in the pattern. This is silly, because it handles
3129             only 0-9, a-f, and A-F, but the character types table is locale-
3130             specific, which means strange things might happen. A private
3131             table is now used for this - though it costs 256 bytes, a table is
3132             much faster than multiple explicit tests. Of course, the standard
3133             character types table is still used for matching digits in subject
3134             strings against \d.
3135    
3136       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
3137             ending in _t are). So I've renamed it as ESC_tee.
3138    
3139    3. The first argument for regexec() in the POSIX wrapper should have been
3140       defined as "const".
3141    
3142    4. Changed pcretest to use malloc() for its buffers so that they can be
3143       Electric Fenced for debugging.
3144    
3145    5. There were several places in the code where, in UTF-8 mode, PCRE would try
3146       to read one or more bytes before the start of the subject string. Often this
3147       had no effect on PCRE's behaviour, but in some circumstances it could
3148       provoke a segmentation fault.
3149    
3150    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
3151       to try to read one or more bytes before the start of the subject string.
3152    
3153    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
3154       UTF-8 support could misbehave in various ways if the subject string
3155       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
3156       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
3157       back over UTF-8 characters.)
3158    
3159    
3160  Version 4.2 14-Apr-03  Version 4.2 14-Apr-03
3161  ---------------------  ---------------------
3162    

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