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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 8.20 21-Oct-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
14        captured substring, but while checking the failing first alternative,
15        substring 1 is temporarily captured. If the output vector supplied to
16        pcre_exec() was not big enough for this capture, the yield of the function
17        was still zero ("insufficient space for captured substrings"). This cannot
18        be totally fixed without adding another stack variable, which seems a lot
19        of expense for a edge case. However, I have improved the situation in cases
20        such as /(a)(b)x|abc/ matched against "abc", where the return code
21        indicates that fewer than the maximum number of slots in the ovector have
22        been set.
23    
24    3.  Related to (2) above: when there are more back references in a pattern than
25        slots in the output vector, pcre_exec() uses temporary memory during
26        matching, and copies in the captures as far as possible afterwards. It was
27        using the entire output vector, but this conflicts with the specification
28        that only 2/3 is used for passing back captured substrings. Now it uses
29        only the first 2/3, for compatibility. This is, of course, another edge
30        case.
31    
32    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
33        main code base, and can be used by building with --enable-jit. When this is
34        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
35        runtime --no-jit option is given.
36    
37    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
38        ovector, the return from the function was zero, implying that there were
39        other matches that did not fit. The correct "exactly full" value is now
40        returned.
41    
42    6.  If a subpattern that was called recursively or as a subroutine contained
43        (*PRUNE) or any other control that caused it to give a non-standard return,
44        invalid errors such as "Error -26 (nested recursion at the same subject
45        position)" or even infinite loops could occur.
46    
47    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
48        computing the minimum length on reaching *ACCEPT, and so ended up with the
49        wrong value of 1 rather than 0. Further investigation indicates that
50        computing a minimum subject length in the presence of *ACCEPT is difficult
51        (think back references, subroutine calls), and so I have changed the code
52        so that no minimum is registered for a pattern that contains *ACCEPT.
53    
54    8.  If (*THEN) was present in the first (true) branch of a conditional group,
55        it was not handled as intended. [But see 16 below.]
56    
57    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
58        Sheri Pierce.
59    
60    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
61        the first byte in a match must be "a".
62    
63    11. Change 17 for 8.13 increased the recursion depth for patterns like
64        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
65        pattern contains any instances of (*THEN). If it does not, the old
66        optimizations are restored. It would be nice to do this on a per-group
67        basis, but at the moment that is not feasible.
68    
69    12. In some environments, the output of pcretest -C is CRLF terminated. This
70        broke RunTest's code that checks for the link size. A single white space
71        character after the value is now allowed for.
72    
73    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
74        For "fr", it uses the Windows-specific input and output files.
75    
76    14. If (*THEN) appeared in a group that was called recursively or as a
77        subroutine, it did not work as intended. [But see next item.]
78    
79    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
80        pattern fragments (but not containing any | characters). If A and B are
81        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
82        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
83        D. In other words, Perl considers parentheses that do not contain any |
84        characters to be part of a surrounding alternative, whereas PCRE was
85        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
86        differently. PCRE now behaves in the same way as Perl, except in the case
87        of subroutine/recursion calls such as (?1) which have in any case always
88        been different (but PCRE had them first :-).
89    
90    16. Related to 15 above: Perl does not treat the | in a conditional group as
91        creating alternatives. Such a group is treated in the same way as an
92        ordinary group without any | characters when processing (*THEN). PCRE has
93        been changed to match Perl's behaviour.
94    
95    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
96        RunGrepTest script failed.
97    
98    18. Change 22 for version 13 caused atomic groups to use more stack. This is
99        inevitable for groups that contain captures, but it can lead to a lot of
100        stack use in large patterns. The old behaviour has been restored for atomic
101        groups that do not contain any capturing parentheses.
102    
103    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
104        suppress the check for a minimum subject length at run time. (If it was
105        given to pcre_exec() or pcre_dfa_exec() it did work.)
106    
107    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
108        fail to work when decoding hex characters in data strings in EBCDIC
109        environments.
110    
111    21. It appears that in at least one Mac OS environment, the isxdigit() function
112        is implemented as a macro that evaluates to its argument more than once,
113        contravening the C 90 Standard (I haven't checked a later standard). There
114        was an instance in pcretest which caused it to go wrong when processing
115        \x{...} escapes in subject strings. The has been rewritten to avoid using
116        things like p++ in the argument of isxdigit().
117    
118    
119    Version 8.13 16-Aug-2011
120    ------------------------
121    
122    1.  The Unicode data tables have been updated to Unicode 6.0.0.
123    
124    2.  Two minor typos in pcre_internal.h have been fixed.
125    
126    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
127        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
128        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
129    
130    4.  There were a number of related bugs in the code for matching backrefences
131        caselessly in UTF-8 mode when codes for the characters concerned were
132        different numbers of bytes. For example, U+023A and U+2C65 are an upper
133        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
134        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
135        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
136        2-byte code at the end of the subject (it thought there wasn't enough data
137        left).
138    
139    5.  Comprehensive information about what went wrong is now returned by
140        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
141        as the output vector has at least 2 elements. The offset of the start of
142        the failing character and a reason code are placed in the vector.
143    
144    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
145        now returned is for the first byte of the failing character, instead of the
146        last byte inspected. This is an incompatible change, but I hope it is small
147        enough not to be a problem. It makes the returned offset consistent with
148        pcre_exec() and pcre_dfa_exec().
149    
150    7.  pcretest now gives a text phrase as well as the error number when
151        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
152        failure, the offset and reason code are output.
153    
154    8.  When \R was used with a maximizing quantifier it failed to skip backwards
155        over a \r\n pair if the subsequent match failed. Instead, it just skipped
156        back over a single character (\n). This seems wrong (because it treated the
157        two characters as a single entity when going forwards), conflicts with the
158        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
159        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
160        has been changed.
161    
162    9.  Some internal refactoring has changed the processing so that the handling
163        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
164        time (the PCRE_DOTALL option was changed this way some time ago: version
165        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
166        which was always a bit of a fudge. It also means that there is one less
167        argument for the match() function, which reduces its stack requirements
168        slightly. This change also fixes an incompatibility with Perl: the pattern
169        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
170    
171    10. More internal refactoring has drastically reduced the number of recursive
172        calls to match() for possessively repeated groups such as (abc)++ when
173        using pcre_exec().
174    
175    11. While implementing 10, a number of bugs in the handling of groups were
176        discovered and fixed:
177    
178        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
179        (a|)*(?1) gave a compile-time internal error.
180        ((a|)+)+  did not notice that the outer group could match an empty string.
181        (^a|^)+   was not marked as anchored.
182        (.*a|.*)+ was not marked as matching at start or after a newline.
183    
184    12. Yet more internal refactoring has removed another argument from the match()
185        function. Special calls to this function are now indicated by setting a
186        value in a variable in the "match data" data block.
187    
188    13. Be more explicit in pcre_study() instead of relying on "default" for
189        opcodes that mean there is no starting character; this means that when new
190        ones are added and accidentally left out of pcre_study(), testing should
191        pick them up.
192    
193    14. The -s option of pcretest has been documented for ages as being an old
194        synonym of -m (show memory usage). I have changed it to mean "force study
195        for every regex", that is, assume /S for every regex. This is similar to -i
196        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
197        using it. It makes it easier to run collections of tests with and without
198        study enabled, and thereby test pcre_study() more easily. All the standard
199        tests are now run with and without -s (but some patterns can be marked as
200        "never study" - see 20 below).
201    
202    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
203        restoration of the capturing data to the outer values was not happening
204        correctly.
205    
206    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
207        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
208        pattern had matched an empty string, and so incorrectly returned a no
209        match.
210    
211    17. There was optimizing code for the last branch of non-capturing parentheses,
212        and also for the obeyed branch of a conditional subexpression, which used
213        tail recursion to cut down on stack usage. Unfortunately, now that there is
214        the possibility of (*THEN) occurring in these branches, tail recursion is
215        no longer possible because the return has to be checked for (*THEN). These
216        two optimizations have therefore been removed. [But see 8.20/11 above.]
217    
218    18. If a pattern containing \R was studied, it was assumed that \R always
219        matched two bytes, thus causing the minimum subject length to be
220        incorrectly computed because \R can also match just one byte.
221    
222    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
223        was incorrectly computed.
224    
225    20. If /S is present twice on a test pattern in pcretest input, it now
226        *disables* studying, thereby overriding the use of -s on the command line
227        (see 14 above). This is necessary for one or two tests to keep the output
228        identical in both cases.
229    
230    21. When (*ACCEPT) was used in an assertion that matched an empty string and
231        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
232    
233    22. When an atomic group that contained a capturing parenthesis was
234        successfully matched, but the branch in which it appeared failed, the
235        capturing was not being forgotten if a higher numbered group was later
236        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
237        group 1 to "a", when in fact it should be unset. This applied to multi-
238        branched capturing and non-capturing groups, repeated or not, and also to
239        positive assertions (capturing in negative assertions does not happen
240        in PCRE) and also to nested atomic groups.
241    
242    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
243        subject after a captured substring, to make it easier to tell which of a
244        number of identical substrings has been captured.
245    
246    24. The way atomic groups are processed by pcre_exec() has been changed so that
247        if they are repeated, backtracking one repetition now resets captured
248        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
249        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
250        "aaa". Previously, it would have been "a". As part of this code
251        refactoring, the way recursive calls are handled has also been changed.
252    
253    25. If an assertion condition captured any substrings, they were not passed
254        back unless some other capturing happened later. For example, if
255        (?(?=(a))a) was matched against "a", no capturing was returned.
256    
257    26. When studying a pattern that contained subroutine calls or assertions,
258        the code for finding the minimum length of a possible match was handling
259        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
260        group 1 called group 2 while simultaneously a separate group 2 called group
261        1). A stack overflow occurred in this case. I have fixed this by limiting
262        the recursion depth to 10.
263    
264    27. Updated RunTest.bat in the distribution to the version supplied by Tom
265        Fortmann. This supports explicit test numbers on the command line, and has
266        argument validation and error reporting.
267    
268    28. An instance of \X with an unlimited repeat could fail if at any point the
269        first character it looked at was a mark character.
270    
271    29. Some minor code refactoring concerning Unicode properties and scripts
272        should reduce the stack requirement of match() slightly.
273    
274    30. Added the '=' option to pcretest to check the setting of unused capturing
275        slots at the end of the pattern, which are documented as being -1, but are
276        not included in the return count.
277    
278    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
279        compiled something random. Now it gives a compile-time error (as does
280        Perl).
281    
282    32. A *MARK encountered during the processing of a positive assertion is now
283        recorded and passed back (compatible with Perl).
284    
285    33. If --only-matching or --colour was set on a pcregrep call whose pattern
286        had alternative anchored branches, the search for a second match in a line
287        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
288        matched the line "0102" twice. The same bug affected patterns that started
289        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
290        twice.
291    
292    34. Previously, PCRE did not allow quantification of assertions. However, Perl
293        does, and because of capturing effects, quantifying parenthesized
294        assertions may at times be useful. Quantifiers are now allowed for
295        parenthesized assertions.
296    
297    35. A minor code tidy in pcre_compile() when checking options for \R usage.
298    
299    36. \g was being checked for fancy things in a character class, when it should
300        just be a literal "g".
301    
302    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
303        appearance of a nested POSIX class supersedes an apparent external class.
304        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
305        unescaped square brackets may also appear as part of class names. For
306        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
307        more like Perl. (But see 8.20/1 above.)
308    
309    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
310        was because it thought it was \N{name}, which is not supported).
311    
312    39. Add minix to OS list not supporting the -S option in pcretest.
313    
314    40. PCRE tries to detect cases of infinite recursion at compile time, but it
315        cannot analyze patterns in sufficient detail to catch mutual recursions
316        such as ((?1))((?2)). There is now a runtime test that gives an error if a
317        subgroup is called recursively as a subpattern for a second time at the
318        same position in the subject string. In previous releases this might have
319        been caught by the recursion limit, or it might have run out of stack.
320    
321    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
322        happen only once. PCRE was, however incorrectly giving a compile time error
323        "recursive call could loop indefinitely" because it cannot analyze the
324        pattern in sufficient detail. The compile time test no longer happens when
325        PCRE is compiling a conditional subpattern, but actual runaway loops are
326        now caught at runtime (see 40 above).
327    
328    42. It seems that Perl allows any characters other than a closing parenthesis
329        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
330        has been changed to be the same.
331    
332    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
333        as not to get warnings when autogen.sh is called. Also changed
334        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
335    
336    44. To help people who use pcregrep to scan files containing exceedingly long
337        lines, the following changes have been made:
338    
339        (a) The default value of the buffer size parameter has been increased from
340            8K to 20K. (The actual buffer used is three times this size.)
341    
342        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
343            PCRE is built.
344    
345        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
346            to be set at run time.
347    
348        (d) Numerical values in pcregrep options can be followed by K or M, for
349            example --buffer-size=50K.
350    
351        (e) If a line being scanned overflows pcregrep's buffer, an error is now
352            given and the return code is set to 2.
353    
354    45. Add a pointer to the latest mark to the callout data block.
355    
356    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
357        partial match of an empty string instead of no match. This was specific to
358        the use of ".".
359    
360    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
361        complete match instead of a partial match. This bug was dependent on both
362        the PCRE_UTF8 and PCRE_DOTALL options being set.
363    
364    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
365        starting byte set, because \b was not being ignored.
366    
367    
368    Version 8.12 15-Jan-2011
369    ------------------------
370    
371    1.  Fixed some typos in the markup of the man pages, and wrote a script that
372        checks for such things as part of the documentation building process.
373    
374    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
375        --match-limit and --recursion-limit options (added for 8.11). In
376        particular, this made one of the standard tests fail. (The integer value
377        went into the wrong half of a long int.)
378    
379    3.  If the --colour option was given to pcregrep with -v (invert match), it
380        did strange things, either producing crazy output, or crashing. It should,
381        of course, ignore a request for colour when reporting lines that do not
382        match.
383    
384    4.  Another pcregrep bug caused similar problems if --colour was specified with
385        -M (multiline) and the pattern match finished with a line ending.
386    
387    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
388        matched in multiline mode, the following line was shown as part of the
389        match. This seems wrong, so I have changed it.
390    
391    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
392        the check for further matches in the same line (so they could be coloured)
393        to overrun the end of the current line. If another match was found, it was
394        incorrectly shown (and then shown again when found in the next line).
395    
396    7.  If pcregrep was compiled under Windows, there was a reference to the
397        function pcregrep_exit() before it was defined. I am assuming this was
398        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
399        reported by a user. I've moved the definition above the reference.
400    
401    
402    Version 8.11 10-Dec-2010
403    ------------------------
404    
405    1.  (*THEN) was not working properly if there were untried alternatives prior
406        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
407        backtracked to try for "b" instead of moving to the next alternative branch
408        at the same level (in this case, to look for "c"). The Perl documentation
409        is clear that when (*THEN) is backtracked onto, it goes to the "next
410        alternative in the innermost enclosing group".
411    
412    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
413        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
414        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
415        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
416        (*THEN).
417    
418    3.  If \s appeared in a character class, it removed the VT character from
419        the class, even if it had been included by some previous item, for example
420        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
421        of \s, but is part of the POSIX "space" class.)
422    
423    4.  A partial match never returns an empty string (because you can always
424        match an empty string at the end of the subject); however the checking for
425        an empty string was starting at the "start of match" point. This has been
426        changed to the "earliest inspected character" point, because the returned
427        data for a partial match starts at this character. This means that, for
428        example, /(?<=abc)def/ gives a partial match for the subject "abc"
429        (previously it gave "no match").
430    
431    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
432        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
433        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
434        has an implication that the given string is incomplete (because a partial
435        match is preferred over a full match). For this reason, these items now
436        give a partial match in this situation. [Aside: previously, the one case
437        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
438        match rather than a full match, which was wrong by the old rules, but is
439        now correct.]
440    
441    6.  There was a bug in the handling of #-introduced comments, recognized when
442        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
443        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
444        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
445        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
446        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
447        places in pcre_compile().
448    
449    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
450        comments when looking ahead for named forward references to subpatterns,
451        the only newline sequence it recognized was NL. It now handles newlines
452        according to the set newline convention.
453    
454    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
455        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
456        cater for a lack of strerror(). These oversights have been fixed.
457    
458    9.  Added --match-limit and --recursion-limit to pcregrep.
459    
460    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
461    
462    11. When the -o option was used, pcregrep was setting a return code of 1, even
463        when matches were found, and --line-buffered was not being honoured.
464    
465    12. Added an optional parentheses number to the -o and --only-matching options
466        of pcregrep.
467    
468    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
469        can match an empty string. The code to do it in pcretest and pcredemo
470        needed fixing:
471    
472        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
473            only one byte after an empty string match just before CRLF (this case
474            just got forgotten; "any" and "anycrlf" were OK).
475    
476        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
477            mode when an empty string match preceded an ASCII character followed by
478            a non-ASCII character. (The code for advancing by one character rather
479            than one byte was nonsense.)
480    
481        (c) The pcredemo.c sample program did not have any code at all to handle
482            the cases when CRLF is a valid newline sequence.
483    
484    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
485        as a starting offset was within the subject string. There is now a new
486        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
487        negative or greater than the length of the string. In order to test this,
488        pcretest is extended to allow the setting of negative starting offsets.
489    
490    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
491        starting offset points to the beginning of a UTF-8 character was
492        unnecessarily clumsy. I tidied it up.
493    
494    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
495        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
496    
497    17. Nobody had reported that the --include_dir option, which was added in
498        release 7.7 should have been called --include-dir (hyphen, not underscore)
499        for compatibility with GNU grep. I have changed it to --include-dir, but
500        left --include_dir as an undocumented synonym, and the same for
501        --exclude-dir, though that is not available in GNU grep, at least as of
502        release 2.5.4.
503    
504    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
505        characters from a string of bytes) have been redefined so as not to use
506        loops, in order to improve performance in some environments. At the same
507        time, I abstracted some of the common code into auxiliary macros to save
508        repetition (this should not affect the compiled code).
509    
510    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
511        compile-time error is now given if \c is not followed by an ASCII
512        character, that is, a byte less than 128. (In EBCDIC mode, the code is
513        different, and any byte value is allowed.)
514    
515    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
516        START_OPTIMIZE option, which is now allowed at compile time - but just
517        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
518        to pcregrep and other applications that have no direct access to PCRE
519        options. The new /Y option in pcretest sets this option when calling
520        pcre_compile().
521    
522    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
523        back references. Groups containing recursive back references were forced to
524        be atomic by that change, but in the case of named groups, the amount of
525        memory required was incorrectly computed, leading to "Failed: internal
526        error: code overflow". This has been fixed.
527    
528    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
529        pcretest.c, to avoid build problems in some Borland environments.
530    
531    
532    Version 8.10 25-Jun-2010
533    ------------------------
534    
535    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
536        THEN.
537    
538    2.  (*ACCEPT) was not working when inside an atomic group.
539    
540    3.  Inside a character class, \B is treated as a literal by default, but
541        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
542        causes the error). The code is unchanged, but I tidied the documentation.
543    
544    4.  Inside a character class, PCRE always treated \R and \X as literals,
545        whereas Perl faults them if its -w option is set. I have changed PCRE so
546        that it faults them when PCRE_EXTRA is set.
547    
548    5.  Added support for \N, which always matches any character other than
549        newline. (It is the same as "." when PCRE_DOTALL is not set.)
550    
551    6.  When compiling pcregrep with newer versions of gcc which may have
552        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
553        declared with attribute warn_unused_result" were given. Just casting the
554        result to (void) does not stop the warnings; a more elaborate fudge is
555        needed. I've used a macro to implement this.
556    
557    7.  Minor change to pcretest.c to avoid a compiler warning.
558    
559    8.  Added four artifical Unicode properties to help with an option to make
560        \s etc use properties (see next item). The new properties are: Xan
561        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
562    
563    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
564        use Unicode properties. (*UCP) at the start of a pattern can be used to set
565        this option. Modified pcretest to add /W to test this facility. Added
566        REG_UCP to make it available via the POSIX interface.
567    
568    10. Added --line-buffered to pcregrep.
569    
570    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
571        studied, and the match started with a letter with a code point greater than
572        127 whose first byte was different to the first byte of the other case of
573        the letter, the other case of this starting letter was not recognized
574        (#976).
575    
576    12. If a pattern that was studied started with a repeated Unicode property
577        test, for example, \p{Nd}+, there was the theoretical possibility of
578        setting up an incorrect bitmap of starting bytes, but fortunately it could
579        not have actually happened in practice until change 8 above was made (it
580        added property types that matched character-matching opcodes).
581    
582    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
583        possible starting bytes for non-anchored patterns.
584    
585    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
586        \R, and also a number of cases that involve Unicode properties, both
587        explicit and implicit when PCRE_UCP is set.
588    
589    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
590        input, it could crash or give wrong results if characters with values
591        greater than 0xc0 were present in the subject string. (Detail: it assumed
592        UTF-8 input when processing these items.)
593    
594    16. Added a lot of (int) casts to avoid compiler warnings in systems where
595        size_t is 64-bit (#991).
596    
597    17. Added a check for running out of memory when PCRE is compiled with
598        --disable-stack-for-recursion (#990).
599    
600    18. If the last data line in a file for pcretest does not have a newline on
601        the end, a newline was missing in the output.
602    
603    19. The default pcre_chartables.c file recognizes only ASCII characters (values
604        less than 128) in its various bitmaps. However, there is a facility for
605        generating tables according to the current locale when PCRE is compiled. It
606        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
607        characters, are recognized by isspace() and therefore were getting set in
608        these tables, and indeed these tables seem to approximate to ISO 8859. This
609        caused a problem in UTF-8 mode when pcre_study() was used to create a list
610        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
611        which of course cannot start UTF-8 characters. I have changed the code so
612        that only real ASCII characters (less than 128) and the correct starting
613        bytes for UTF-8 encodings are set for characters greater than 127 when in
614        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
615        altogether.)
616    
617    20. Added the /T option to pcretest so as to be able to run tests with non-
618        standard character tables, thus making it possible to include the tests
619        used for 19 above in the standard set of tests.
620    
621    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
622        reference to a subpattern the other side of a comment that contains an
623        opening parenthesis caused either an internal compiling error, or a
624        reference to the wrong subpattern.
625    
626    
627    Version 8.02 19-Mar-2010
628    ------------------------
629    
630    1.  The Unicode data tables have been updated to Unicode 5.2.0.
631    
632    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
633        configured.
634    
635    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
636        original author of that file, following a query about its status.
637    
638    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
639        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
640    
641    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
642        quantifier applied to a forward-referencing subroutine call, could compile
643        incorrect code or give the error "internal error: previously-checked
644        referenced subpattern not found".
645    
646    6.  Both MS Visual Studio and Symbian OS have problems with initializing
647        variables to point to external functions. For these systems, therefore,
648        pcre_malloc etc. are now initialized to local functions that call the
649        relevant global functions.
650    
651    7.  There were two entries missing in the vectors called coptable and poptable
652        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
653        I've fixed the data, and added a kludgy way of testing at compile time that
654        the lengths are correct (equal to the number of opcodes).
655    
656    8.  Following on from 7, I added a similar kludge to check the length of the
657        eint vector in pcreposix.c.
658    
659    9.  Error texts for pcre_compile() are held as one long string to avoid too
660        much relocation at load time. To find a text, the string is searched,
661        counting zeros. There was no check for running off the end of the string,
662        which could happen if a new error number was added without updating the
663        string.
664    
665    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
666    
667    11. \K was not working if it appeared in an atomic group or in a group that
668        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
669        \K is "not well defined" if used in an assertion. PCRE now accepts it if
670        the assertion is positive, but not if it is negative.
671    
672    12. Change 11 fortuitously reduced the size of the stack frame used in the
673        "match()" function of pcre_exec.c by one pointer. Forthcoming
674        implementation of support for (*MARK) will need an extra pointer on the
675        stack; I have reserved it now, so that the stack frame size does not
676        decrease.
677    
678    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
679        item in branch that calls a recursion is a subroutine call - as in the
680        second branch in the above example - was incorrectly given the compile-
681        time error "recursive call could loop indefinitely" because pcre_compile()
682        was not correctly checking the subroutine for matching a non-empty string.
683    
684    14. The checks for overrunning compiling workspace could trigger after an
685        overrun had occurred. This is a "should never occur" error, but it can be
686        triggered by pathological patterns such as hundreds of nested parentheses.
687        The checks now trigger 100 bytes before the end of the workspace.
688    
689    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
690    
691    
692    Version 8.01 19-Jan-2010
693    ------------------------
694    
695    1.  If a pattern contained a conditional subpattern with only one branch (in
696        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
697        computed the wrong minimum data length (which is of course zero for such
698        subpatterns). This could cause incorrect "no match" results.
699    
700    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
701        the pattern is reset in the first branch, pcre_compile() failed with
702        "internal error: code overflow at offset...". This happened only when
703        the reset was to the original external option setting. (An optimization
704        abstracts leading options settings into an external setting, which was the
705        cause of this.)
706    
707    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
708        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
709        assertion pattern did not match (meaning that the assertion was true), it
710        was incorrectly treated as false if the SKIP had been reached during the
711        matching. This also applied to assertions used as conditions.
712    
713    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
714        assertion subpattern, including such a pattern used as a condition,
715        unpredictable results occurred, instead of the error return
716        PCRE_ERROR_DFA_UITEM.
717    
718    5.  The C++ GlobalReplace function was not working like Perl for the special
719        situation when an empty string is matched. It now does the fancy magic
720        stuff that is necessary.
721    
722    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
723        removed. (These were left over from very, very early versions of PCRE.)
724    
725    7.  Some cosmetic changes to the code to make life easier when compiling it
726        as part of something else:
727    
728        (a) Change DEBUG to PCRE_DEBUG.
729    
730        (b) In pcre_compile(), rename the member of the "branch_chain" structure
731            called "current" as "current_branch", to prevent a collision with the
732            Linux macro when compiled as a kernel module.
733    
734        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
735            prevent a collision with the Linux macro when compiled as a kernel
736            module.
737    
738    8.  In pcre_compile() there are some checks for integer overflows that used to
739        cast potentially large values to (double). This has been changed to that
740        when building, a check for int64_t is made, and if it is found, it is used
741        instead, thus avoiding the use of floating point arithmetic. (There is no
742        other use of FP in PCRE.) If int64_t is not found, the fallback is to
743        double.
744    
745    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
746        2005 (difference between two addresses compared to an unsigned value).
747    
748    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
749        custom one, because of the following reported problem in Windows:
750    
751          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
752              under Win32.
753          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
754              therefore missing the function definition.
755          - The compiler thus generates a "C" signature for the test function.
756          - The linker fails to find the "C" function.
757          - PCRE fails to configure if asked to do so against libbz2.
758    
759    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
760        messages were output:
761    
762          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
763          rerunning libtoolize, to keep the correct libtool macros in-tree.
764          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
765    
766        I have done both of these things.
767    
768    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
769        most of the time, it *can* run out if it is given a pattern that contains a
770        runaway infinite recursion. I updated the discussion in the pcrestack man
771        page.
772    
773    13. Now that we have gone to the x.xx style of version numbers, the minor
774        version may start with zero. Using 08 or 09 is a bad idea because users
775        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
776        interpreted as invalid octal numbers. I've updated the previous comment in
777        configure.ac, and also added a check that gives an error if 08 or 09 are
778        used.
779    
780    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
781        causing partial matching to fail when the end of the subject matched \W
782        in a UTF-8 pattern where \W was quantified with a minimum of 3.
783    
784    15. There were some discrepancies between the declarations in pcre_internal.h
785        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
786        their definitions. The declarations used "const uschar *" and the
787        definitions used USPTR. Even though USPTR is normally defined as "const
788        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
789        reported that: "This difference in casting confuses some C++ compilers, for
790        example, SunCC recognizes above declarations as different functions and
791        generates broken code for hbpcre." I have changed the declarations to use
792        USPTR.
793    
794    16. GNU libtool is named differently on some systems. The autogen.sh script now
795        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
796        (FreeBSD).
797    
798    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
799        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
800        comment: "Figure out how to create a longlong from a string: strtoll and
801        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
802        instance, but it only takes 2 args instead of 3!"
803    
804    18. A subtle bug concerned with back references has been fixed by a change of
805        specification, with a corresponding code fix. A pattern such as
806        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
807        refers, was giving matches when it shouldn't. For example, xa=xaaa would
808        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
809        same bug. Such groups have to be quantified to be useful, or contained
810        inside another quantified group. (If there's no repetition, the reference
811        can never match.) The problem arises because, having left the group and
812        moved on to the rest of the pattern, a later failure that backtracks into
813        the group uses the captured value from the final iteration of the group
814        rather than the correct earlier one. I have fixed this in PCRE by forcing
815        any group that contains a reference to itself to be an atomic group; that
816        is, there cannot be any backtracking into it once it has completed. This is
817        similar to recursive and subroutine calls.
818    
819    
820    Version 8.00 19-Oct-09
821    ----------------------
822    
823    1.  The table for translating pcre_compile() error codes into POSIX error codes
824        was out-of-date, and there was no check on the pcre_compile() error code
825        being within the table. This could lead to an OK return being given in
826        error.
827    
828    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
829        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
830        in a Windows environment.
831    
832    3.  The pcregrep --count option prints the count for each file even when it is
833        zero, as does GNU grep. However, pcregrep was also printing all files when
834        --files-with-matches was added. Now, when both options are given, it prints
835        counts only for those files that have at least one match. (GNU grep just
836        prints the file name in this circumstance, but including the count seems
837        more useful - otherwise, why use --count?) Also ensured that the
838        combination -clh just lists non-zero counts, with no names.
839    
840    4.  The long form of the pcregrep -F option was incorrectly implemented as
841        --fixed_strings instead of --fixed-strings. This is an incompatible change,
842        but it seems right to fix it, and I didn't think it was worth preserving
843        the old behaviour.
844    
845    5.  The command line items --regex=pattern and --regexp=pattern were not
846        recognized by pcregrep, which required --regex pattern or --regexp pattern
847        (with a space rather than an '='). The man page documented the '=' forms,
848        which are compatible with GNU grep; these now work.
849    
850    6.  No libpcreposix.pc file was created for pkg-config; there was just
851        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
852    
853    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
854        when UCP support is not needed, by modifying the Python script that
855        generates it from Unicode data files. This should not matter if the module
856        is correctly used as a library, but I received one complaint about 50K of
857        unwanted data. My guess is that the person linked everything into his
858        program rather than using a library. Anyway, it does no harm.
859    
860    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
861        was a minimum greater than 1 for a wide character in a possessive
862        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
863        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
864        character. Chaos in the form of incorrect output or a compiling loop could
865        result.
866    
867    9.  The restrictions on what a pattern can contain when partial matching is
868        requested for pcre_exec() have been removed. All patterns can now be
869        partially matched by this function. In addition, if there are at least two
870        slots in the offset vector, the offset of the earliest inspected character
871        for the match and the offset of the end of the subject are set in them when
872        PCRE_ERROR_PARTIAL is returned.
873    
874    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
875        synonymous with PCRE_PARTIAL, for backwards compatibility, and
876        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
877        and may be more useful for multi-segment matching.
878    
879    11. Partial matching with pcre_exec() is now more intuitive. A partial match
880        used to be given if ever the end of the subject was reached; now it is
881        given only if matching could not proceed because another character was
882        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
883        string "Z", which now yields "no match" instead of "partial match". In the
884        case of pcre_dfa_exec(), "no match" is given if every matching path for the
885        final character ended with (*FAIL).
886    
887    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
888        if the pattern had a "must contain" character that was already found in the
889        earlier partial match, unless partial matching was again requested. For
890        example, with the pattern /dog.(body)?/, the "must contain" character is
891        "g". If the first part-match was for the string "dog", restarting with
892        "sbody" failed. This bug has been fixed.
893    
894    13. The string returned by pcre_dfa_exec() after a partial match has been
895        changed so that it starts at the first inspected character rather than the
896        first character of the match. This makes a difference only if the pattern
897        starts with a lookbehind assertion or \b or \B (\K is not supported by
898        pcre_dfa_exec()). It's an incompatible change, but it makes the two
899        matching functions compatible, and I think it's the right thing to do.
900    
901    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
902        so that the demonstration program is easily available in environments where
903        PCRE has not been installed from source.
904    
905    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
906        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
907        library.
908    
909    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
910        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
911        is not the first non-POSIX option to be added. Clearly some people find
912        these options useful.
913    
914    17. If a caller to the POSIX matching function regexec() passes a non-zero
915        value for nmatch with a NULL value for pmatch, the value of
916        nmatch is forced to zero.
917    
918    18. RunGrepTest did not have a test for the availability of the -u option of
919        the diff command, as RunTest does. It now checks in the same way as
920        RunTest, and also checks for the -b option.
921    
922    19. If an odd number of negated classes containing just a single character
923        interposed, within parentheses, between a forward reference to a named
924        subpattern and the definition of the subpattern, compilation crashed with
925        an internal error, complaining that it could not find the referenced
926        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
927        [The bug was that it was starting one character too far in when skipping
928        over the character class, thus treating the ] as data rather than
929        terminating the class. This meant it could skip too much.]
930    
931    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
932        /g option in pcretest when the pattern contains \K, which makes it possible
933        to have an empty string match not at the start, even when the pattern is
934        anchored. Updated pcretest and pcredemo to use this option.
935    
936    21. If the maximum number of capturing subpatterns in a recursion was greater
937        than the maximum at the outer level, the higher number was returned, but
938        with unset values at the outer level. The correct (outer level) value is
939        now given.
940    
941    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
942        PCRE did not set those parentheses (unlike Perl). I have now found a way to
943        make it do so. The string so far is captured, making this feature
944        compatible with Perl.
945    
946    23. The tests have been re-organized, adding tests 11 and 12, to make it
947        possible to check the Perl 5.10 features against Perl 5.10.
948    
949    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
950        pattern matches a fixed length string. PCRE did not allow this; now it
951        does. Neither allows recursion.
952    
953    25. I finally figured out how to implement a request to provide the minimum
954        length of subject string that was needed in order to match a given pattern.
955        (It was back references and recursion that I had previously got hung up
956        on.) This code has now been added to pcre_study(); it finds a lower bound
957        to the length of subject needed. It is not necessarily the greatest lower
958        bound, but using it to avoid searching strings that are too short does give
959        some useful speed-ups. The value is available to calling programs via
960        pcre_fullinfo().
961    
962    26. While implementing 25, I discovered to my embarrassment that pcretest had
963        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
964        study optimizations had never been tested with that matching function.
965        Oops. What is worse, even when it was passed study data, there was a bug in
966        pcre_dfa_exec() that meant it never actually used it. Double oops. There
967        were also very few tests of studied patterns with pcre_dfa_exec().
968    
969    27. If (?| is used to create subpatterns with duplicate numbers, they are now
970        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
971        on the other side of the coin, they are no longer allowed to have different
972        names, because these cannot be distinguished in PCRE, and this has caused
973        confusion. (This is a difference from Perl.)
974    
975    28. When duplicate subpattern names are present (necessarily with different
976        numbers, as required by 27 above), and a test is made by name in a
977        conditional pattern, either for a subpattern having been matched, or for
978        recursion in such a pattern, all the associated numbered subpatterns are
979        tested, and the overall condition is true if the condition is true for any
980        one of them. This is the way Perl works, and is also more like the way
981        testing by number works.
982    
983    
984    Version 7.9 11-Apr-09
985    ---------------------
986    
987    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
988        (pcretest), all targets were linked against these libraries. This included
989        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
990        libraries. This caused unwanted dependencies to be created. This problem
991        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
992        pcretest is linked with readline.
993    
994    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
995        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
996        moved outside it again, because FALSE and TRUE are already defined in AIX,
997        but BOOL is not.
998    
999    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1000        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1001    
1002    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1003        hyphens) following file names and line numbers when outputting matching
1004        lines. This is not true; no spaces are inserted. I have also clarified the
1005        wording for the --colour (or --color) option.
1006    
1007    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1008        was not coloured; this is different to GNU grep, so I have changed it to be
1009        the same.
1010    
1011    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1012        each matching line was coloured. Now it goes on to look for further matches
1013        of any of the test patterns, which is the same behaviour as GNU grep.
1014    
1015    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1016        doesn't make sense to accept an empty string match in pcregrep, so I have
1017        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1018        seems to be how GNU grep behaves.
1019    
1020    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1021        start or after a newline", because the conditional assertion was not being
1022        correctly handled. The rule now is that both the assertion and what follows
1023        in the first alternative must satisfy the test.
1024    
1025    9.  If auto-callout was enabled in a pattern with a conditional group whose
1026        condition was an assertion, PCRE could crash during matching, both with
1027        pcre_exec() and pcre_dfa_exec().
1028    
1029    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1030        used for matching.
1031    
1032    11. Unicode property support in character classes was not working for
1033        characters (bytes) greater than 127 when not in UTF-8 mode.
1034    
1035    12. Added the -M command line option to pcretest.
1036    
1037    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1038    
1039    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1040    
1041    16. Added comments and documentation about mis-use of no_arg in the C++
1042        wrapper.
1043    
1044    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1045        from Martin Jerabek that uses macro names for all relevant character and
1046        string constants.
1047    
1048    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1049        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1050        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1051        these, but not everybody uses configure.
1052    
1053    19. A conditional group that had only one branch was not being correctly
1054        recognized as an item that could match an empty string. This meant that an
1055        enclosing group might also not be so recognized, causing infinite looping
1056        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1057        with the subject "ab", where knowledge that the repeated group can match
1058        nothing is needed in order to break the loop.
1059    
1060    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1061        exec(), but without supplying a callout function, matching went wrong.
1062    
1063    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1064        leak if the size of the offset vector was greater than 30. When the vector
1065        is smaller, the saved offsets during recursion go onto a local stack
1066        vector, but for larger vectors malloc() is used. It was failing to free
1067        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1068        error, in fact).
1069    
1070    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1071        heapframe that is used only when UTF-8 support is enabled. This caused no
1072        problem, but was untidy.
1073    
1074    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1075        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1076        included within another project.
1077    
1078    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1079        slightly modified by me:
1080    
1081          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1082              not building pcregrep.
1083    
1084          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1085              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1086    
1087    25. Forward references, both numeric and by name, in patterns that made use of
1088        duplicate group numbers, could behave incorrectly or give incorrect errors,
1089        because when scanning forward to find the reference group, PCRE was not
1090        taking into account the duplicate group numbers. A pattern such as
1091        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1092    
1093    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1094        the feature of a custom pointer more persuasive (as requested by a user).
1095    
1096    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1097        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1098        pre-defined.
1099    
1100    28. Added support for (*UTF8) at the start of a pattern.
1101    
1102    29. Arrange for flags added by the "release type" setting in CMake to be shown
1103        in the configuration summary.
1104    
1105    
1106    Version 7.8 05-Sep-08
1107    ---------------------
1108    
1109    1.  Replaced UCP searching code with optimized version as implemented for Ad
1110        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1111        stage table and inline lookup instead of a function, giving speed ups of 2
1112        to 5 times on some simple patterns that I tested. Permission was given to
1113        distribute the MultiStage2.py script that generates the tables (it's not in
1114        the tarball, but is in the Subversion repository).
1115    
1116    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1117        scripts.
1118    
1119    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1120        a group with a zero qualifier. The result of the study could be incorrect,
1121        or the function might crash, depending on the pattern.
1122    
1123    4.  Caseless matching was not working for non-ASCII characters in back
1124        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1125        It now works when Unicode Property Support is available.
1126    
1127    5.  In pcretest, an escape such as \x{de} in the data was always generating
1128        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1129        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1130        truncation.
1131    
1132    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1133    
1134    7.  Added two (int) casts to pcregrep when printing the difference of two
1135        pointers, in case they are 64-bit values.
1136    
1137    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1138        test 2 if it fails.
1139    
1140    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1141        and a #define of that name to empty if it is not externally set. This is to
1142        allow users of MSVC to set it if necessary.
1143    
1144    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1145        the convenience functions in the pcre_get.c source file.
1146    
1147    11. An option change at the start of a pattern that had top-level alternatives
1148        could cause overwriting and/or a crash. This command provoked a crash in
1149        some environments:
1150    
1151          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1152    
1153        This potential security problem was recorded as CVE-2008-2371.
1154    
1155    12. For a pattern where the match had to start at the beginning or immediately
1156        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1157        pcre_dfa_exec() could read past the end of the passed subject if there was
1158        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1159        pcretest so that it places the subject at the end of its malloc-ed buffer.
1160    
1161    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1162        exec() might read past the end of the data buffer in UTF-8 mode.
1163    
1164    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1165        the data contained the byte 0x85 as part of a UTF-8 character within its
1166        first line. This applied both to normal and DFA matching.
1167    
1168    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1169        /^[^d]*?$/8 failed to match "abc".
1170    
1171    16. Added a missing copyright notice to pcrecpp_internal.h.
1172    
1173    17. Make it more clear in the documentation that values returned from
1174        pcre_exec() in ovector are byte offsets, not character counts.
1175    
1176    18. Tidied a few places to stop certain compilers from issuing warnings.
1177    
1178    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1179        supplied by Stefan Weber. I made a further small update for 7.8 because
1180        there is a change of source arrangements: the pcre_searchfuncs.c module is
1181        replaced by pcre_ucd.c.
1182    
1183    
1184    Version 7.7 07-May-08
1185    ---------------------
1186    
1187    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1188        a string to a long long, pretend we don't even have a long long." This is
1189        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1190    
1191    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1192        pre-7.6 versions, which defined a global no_arg variable instead of putting
1193        it in the RE class. (See also #8 below.)
1194    
1195    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1196        Lopes.
1197    
1198    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1199    
1200        (1) The include/exclude patterns were being applied to the whole pathnames
1201            of files, instead of just to the final components.
1202    
1203        (2) If there was more than one level of directory, the subdirectories were
1204            skipped unless they satisfied the include/exclude conditions. This is
1205            inconsistent with GNU grep (and could even be seen as contrary to the
1206            pcregrep specification - which I improved to make it absolutely clear).
1207            The action now is always to scan all levels of directory, and just
1208            apply the include/exclude patterns to regular files.
1209    
1210    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1211        --exclude_dir in the tests to avoid scanning .svn directories.
1212    
1213    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1214        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1215        doesn't support NULs in patterns.
1216    
1217    7.  Added some missing "const"s to declarations of static tables in
1218        pcre_compile.c and pcre_dfa_exec.c.
1219    
1220    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1221        caused by fix #2  above. (Subsequently also a second patch to fix the
1222        first patch. And a third patch - this was a messy problem.)
1223    
1224    9.  Applied Craig's patch to remove the use of push_back().
1225    
1226    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1227        matching function regexec().
1228    
1229    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1230        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1231        references. PCRE supports relative numbers with this syntax (I don't think
1232        Oniguruma does).
1233    
1234    12. Previously, a group with a zero repeat such as (...){0} was completely
1235        omitted from the compiled regex. However, this means that if the group
1236        was called as a subroutine from elsewhere in the pattern, things went wrong
1237        (an internal error was given). Such groups are now left in the compiled
1238        pattern, with a new opcode that causes them to be skipped at execution
1239        time.
1240    
1241    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1242        to the way PCRE behaves:
1243    
1244        (a) A lone ] character is dis-allowed (Perl treats it as data).
1245    
1246        (b) A back reference to an unmatched subpattern matches an empty string
1247            (Perl fails the current match path).
1248    
1249        (c) A data ] in a character class must be notated as \] because if the
1250            first data character in a class is ], it defines an empty class. (In
1251            Perl it is not possible to have an empty class.) The empty class []
1252            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1253            The negative empty class [^] matches any one character, independently
1254            of the DOTALL setting.
1255    
1256    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1257        non-existent subpattern following a character class starting with ']' and
1258        containing () gave an internal compiling error instead of "reference to
1259        non-existent subpattern". Fortunately, when the pattern did exist, the
1260        compiled code was correct. (When scanning forwards to check for the
1261        existencd of the subpattern, it was treating the data ']' as terminating
1262        the class, so got the count wrong. When actually compiling, the reference
1263        was subsequently set up correctly.)
1264    
1265    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1266        it was being rejected as not supported by pcre_dfa_exec(), even though
1267        other assertions are supported. I have made pcre_dfa_exec() support
1268        (*FAIL).
1269    
1270    16. The implementation of 13c above involved the invention of a new opcode,
1271        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1272        cannot be changed at match time, I realized I could make a small
1273        improvement to matching performance by compiling OP_ALLANY instead of
1274        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1275        on the OP_ANY path.
1276    
1277    17. Compiling pcretest on Windows with readline support failed without the
1278        following two fixes: (1) Make the unistd.h include conditional on
1279        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1280    
1281    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1282        ncurses library to be included for pcretest when ReadLine support is
1283        requested, but also to allow for it to be overridden. This patch came from
1284        Daniel Bergström.
1285    
1286    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1287        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1288        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1289        spotting this.
1290    
1291    
1292    Version 7.6 28-Jan-08
1293    ---------------------
1294    
1295    1.  A character class containing a very large number of characters with
1296        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1297        overflow.
1298    
1299    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1300        HAVE_LONG_LONG is not defined.
1301    
1302    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1303        bring them up to date and include new features. This patch includes:
1304    
1305        - Fixed PH's badly added libz and libbz2 support.
1306        - Fixed a problem with static linking.
1307        - Added pcredemo. [But later removed - see 7 below.]
1308        - Fixed dftables problem and added an option.
1309        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1310            HAVE_LONG_LONG.
1311        - Added readline support for pcretest.
1312        - Added an listing of the option settings after cmake has run.
1313    
1314    4.  A user submitted a patch to Makefile that makes it easy to create
1315        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1316        Makefile.am that cause it to include this special target, without
1317        affecting anything else. Note that the same mingw target plus all
1318        the other distribution libraries and programs are now supported
1319        when configuring with CMake (see 6 below) instead of with
1320        Configure/Make.
1321    
1322    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1323        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1324        exported in the Windows port". It has not yet been confirmed that the patch
1325        solves the problem, but it does no harm.
1326    
1327    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1328        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1329        with CMake, and also correct the comment about stack recursion.
1330    
1331    7.  Remove the automatic building of pcredemo from the ./configure system and
1332        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1333        of a program that users should build themselves after PCRE is installed, so
1334        building it automatically is not really right. What is more, it gave
1335        trouble in some build environments.
1336    
1337    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1338    
1339    
1340    Version 7.5 10-Jan-08
1341    ---------------------
1342    
1343    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1344        values in parens when parsing an RE using the C++ wrapper."
1345    
1346    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1347        Characters greater than 255 were excluded from the class instead of being
1348        included.
1349    
1350    3.  The same bug as (2) above applied to negated POSIX classes such as
1351        [:^space:].
1352    
1353    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1354        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1355        I have changed it.
1356    
1357    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1358        first named subpattern) and a construct such as (?&a) would reference the
1359        first named subpattern whose name started with "a" (in other words, the
1360        length check was missing). Both these problems are fixed. "Subpattern name
1361        expected" is now given for (?&) (a zero-length name), and this patch also
1362        makes it give the same error for \k'' (previously it complained that that
1363        was a reference to a non-existent subpattern).
1364    
1365    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1366        this is right because (?- can be followed by option settings as well as by
1367        digits. I have, however, made the messages clearer.
1368    
1369    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1370        than the number used in the conditional) now cause a compile-time error.
1371        This is actually not compatible with Perl, which accepts such patterns, but
1372        treats the conditional as always being FALSE (as PCRE used to), but it
1373        seems to me that giving a diagnostic is better.
1374    
1375    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1376        and messages.
1377    
1378    9.  Fix two occurrences of "backslash" in comments that should have been
1379        "backspace".
1380    
1381    10. Remove two redundant lines of code that can never be obeyed (their function
1382        was moved elsewhere).
1383    
1384    11. The program that makes PCRE's Unicode character property table had a bug
1385        which caused it to generate incorrect table entries for sequences of
1386        characters that have the same character type, but are in different scripts.
1387        It amalgamated them into a single range, with the script of the first of
1388        them. In other words, some characters were in the wrong script. There were
1389        thirteen such cases, affecting characters in the following ranges:
1390    
1391          U+002b0 - U+002c1
1392          U+0060c - U+0060d
1393          U+0061e - U+00612
1394          U+0064b - U+0065e
1395          U+0074d - U+0076d
1396          U+01800 - U+01805
1397          U+01d00 - U+01d77
1398          U+01d9b - U+01dbf
1399          U+0200b - U+0200f
1400          U+030fc - U+030fe
1401          U+03260 - U+0327f
1402          U+0fb46 - U+0fbb1
1403          U+10450 - U+1049d
1404    
1405    12. The -o option (show only the matching part of a line) for pcregrep was not
1406        compatible with GNU grep in that, if there was more than one match in a
1407        line, it showed only the first of them. It now behaves in the same way as
1408        GNU grep.
1409    
1410    13. If the -o and -v options were combined for pcregrep, it printed a blank
1411        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1412        does the same. The return code can be used to tell if there were any
1413        non-matching lines.
1414    
1415    14. Added --file-offsets and --line-offsets to pcregrep.
1416    
1417    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1418        infinitely looping recursion. The bug was that positive lookaheads were not
1419        being skipped when checking for a possible empty match (negative lookaheads
1420        and both kinds of lookbehind were skipped).
1421    
1422    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1423        inclusion of <windows.h> to before rather than after the definition of
1424        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1425    
1426    17. Specifying a possessive quantifier with a specific limit for a Unicode
1427        character property caused pcre_compile() to compile bad code, which led at
1428        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1429        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1430        caused the error; without that there was no problem.
1431    
1432    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1433    
1434    19. Added --enable-pcretest-libreadline.
1435    
1436    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1437        RE::GlobalReplace(). As a result, the number of replacements returned was
1438        double what it should be. I removed one of the increments, but Craig sent a
1439        later patch that removed the other one (the right fix) and added unit tests
1440        that check the return values (which was not done before).
1441    
1442    21. Several CMake things:
1443    
1444        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1445            the names libpcre and libpcreposix, not just pcre and pcreposix.
1446    
1447        (2) The above change means that pcretest and pcregrep are now correctly
1448            linked with the newly-built libraries, not previously installed ones.
1449    
1450        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1451    
1452    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1453        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1454        UTF-8 newline character). The key issue is that the pattern starts .*;
1455        this means that the match must be either at the beginning, or after a
1456        newline. The bug was in the code for advancing after a failed match and
1457        checking that the new position followed a newline. It was not taking
1458        account of UTF-8 characters correctly.
1459    
1460    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1461        character classes. PCRE was not treating the sequence [:...:] as a
1462        character class unless the ... were all letters. Perl, however, seems to
1463        allow any characters between [: and :], though of course it rejects as
1464        unknown any "names" that contain non-letters, because all the known class
1465        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1466        for example, whereas PCRE did not - it did not recognize a POSIX character
1467        class. This seemed a bit dangerous, so the code has been changed to be
1468        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1469        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1470        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1471        Perl does, and where it didn't before.
1472    
1473    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1474        Windows environments %n is disabled by default.
1475    
1476    
1477    Version 7.4 21-Sep-07
1478    ---------------------
1479    
1480    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1481        means that a class such as [\s] counted as "explicit reference to CR or
1482        LF". That isn't really right - the whole point of the change was to try to
1483        help when there was an actual mention of one of the two characters. So now
1484        the change happens only if \r or \n (or a literal CR or LF) character is
1485        encountered.
1486    
1487    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1488        of both had grown to the point where there were only 3 bits left.
1489        Fortunately, there was spare space in the data structure, and so I have
1490        moved the internal flags into a new 16-bit field to free up more option
1491        bits.
1492    
1493    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1494        but did not set the internal JCHANGED flag - either of these is enough to
1495        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1496        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1497        start sets both bits.
1498    
1499    4.  Added options (at build time, compile time, exec time) to change \R from
1500        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1501    
1502    5.  doc/pcresyntax.html was missing from the distribution.
1503    
1504    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1505        compatibility, even though it is no longer used.
1506    
1507    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1508        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1509        windows.h file is present (where different names are used). [This was
1510        reversed later after testing - see 16 below.]
1511    
1512    8.  Changed all #include <config.h> to #include "config.h". There were also
1513        some further <pcre.h> cases that I changed to "pcre.h".
1514    
1515    9.  When pcregrep was used with the --colour option, it missed the line ending
1516        sequence off the lines that it output.
1517    
1518    10. It was pointed out to me that arrays of string pointers cause lots of
1519        relocations when a shared library is dynamically loaded. A technique of
1520        using a single long string with a table of offsets can drastically reduce
1521        these. I have refactored PCRE in four places to do this. The result is
1522        dramatic:
1523    
1524          Originally:                          290
1525          After changing UCP table:            187
1526          After changing error message table:   43
1527          After changing table of "verbs"       36
1528          After changing table of Posix names   22
1529    
1530        Thanks to the folks working on Gregex for glib for this insight.
1531    
1532    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1533        unicode-properties was also set.
1534    
1535    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1536    
1537    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1538        checked only for CRLF.
1539    
1540    14. Added casts to pcretest.c to avoid compiler warnings.
1541    
1542    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1543    
1544    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1545        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1546        entirely. This removes changes made in 7 above.
1547    
1548    17. The CMake files have been updated, and there is now more information about
1549        building with CMake in the NON-UNIX-USE document.
1550    
1551    
1552    Version 7.3 28-Aug-07
1553    ---------------------
1554    
1555     1. In the rejigging of the build system that eventually resulted in 7.1, the
1556        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1557        brackets there is not right, since it causes compilers to look for an
1558        installed pcre.h, not the version that is in the source that is being
1559        compiled (which of course may be different). I have changed it back to:
1560    
1561          #include "pcre.h"
1562    
1563        I have a vague recollection that the change was concerned with compiling in
1564        different directories, but in the new build system, that is taken care of
1565        by the VPATH setting the Makefile.
1566    
1567     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1568        when the subject happened to end in the byte 0x85 (e.g. if the last
1569        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1570        characters but of course it shouldn't be taken as a newline when it is part
1571        of another character. The bug was that, for an unlimited repeat of . in
1572        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1573        characters when looking for a newline.
1574    
1575     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1576    
1577     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1578        in debug output.
1579    
1580     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1581        long printing in the pcrecpp unittest when running under MinGW.
1582    
1583     6. ESC_K was left out of the EBCDIC table.
1584    
1585     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1586        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1587        limit also applies to "virtual nesting" when a pattern is recursive, and in
1588        this case 1000 isn't so big. I have been able to remove this limit at the
1589        expense of backing off one optimization in certain circumstances. Normally,
1590        when pcre_exec() would call its internal match() function recursively and
1591        immediately return the result unconditionally, it uses a "tail recursion"
1592        feature to save stack. However, when a subpattern that can match an empty
1593        string has an unlimited repetition quantifier, it no longer makes this
1594        optimization. That gives it a stack frame in which to save the data for
1595        checking that an empty string has been matched. Previously this was taken
1596        from the 1000-entry workspace that had been reserved. So now there is no
1597        explicit limit, but more stack is used.
1598    
1599     8. Applied Daniel's patches to solve problems with the import/export magic
1600        syntax that is required for Windows, and which was going wrong for the
1601        pcreposix and pcrecpp parts of the library. These were overlooked when this
1602        problem was solved for the main library.
1603    
1604     9. There were some crude static tests to avoid integer overflow when computing
1605        the size of patterns that contain repeated groups with explicit upper
1606        limits. As the maximum quantifier is 65535, the maximum group length was
1607        set at 30,000 so that the product of these two numbers did not overflow a
1608        32-bit integer. However, it turns out that people want to use groups that
1609        are longer than 30,000 bytes (though not repeat them that many times).
1610        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1611        made it possible to implement the integer overflow checks in a much more
1612        dynamic way, which I have now done. The artificial limitation on group
1613        length has been removed - we now have only the limit on the total length of
1614        the compiled pattern, which depends on the LINK_SIZE setting.
1615    
1616    10. Fixed a bug in the documentation for get/copy named substring when
1617        duplicate names are permitted. If none of the named substrings are set, the
1618        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1619        empty string.
1620    
1621    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1622        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1623        because the ] is interpreted as the first data character and the
1624        terminating ] is not found. PCRE has been made compatible with Perl in this
1625        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1626        cause memory overwriting.
1627    
1628    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1629        string has been matched (to stop an infinite loop). It was not recognizing
1630        a conditional subpattern that could match an empty string if that
1631        subpattern was within another subpattern. For example, it looped when
1632        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1633        condition was not nested. This bug has been fixed.
1634    
1635    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1636        past the start of the subject in the presence of bytes with the top bit
1637        set, for example "\x8aBCD".
1638    
1639    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1640        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1641    
1642    14. Optimized (?!) to (*FAIL).
1643    
1644    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1645        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1646        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1647        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1648        does: it's just the validity check that is more restrictive.
1649    
1650    16. Inserted checks for integer overflows during escape sequence (backslash)
1651        processing, and also fixed erroneous offset values for syntax errors during
1652        backslash processing.
1653    
1654    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1655        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1656    
1657    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1658        caused an overrun.
1659    
1660    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1661        something other than just ASCII characters) inside a group that had an
1662        unlimited repeat caused a loop at compile time (while checking to see
1663        whether the group could match an empty string).
1664    
1665    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1666        [\P{Any}] did so. (Error in the code for printing property names.)
1667    
1668    21. An orphan \E inside a character class could cause a crash.
1669    
1670    22. A repeated capturing bracket such as (A)? could cause a wild memory
1671        reference during compilation.
1672    
1673    23. There are several functions in pcre_compile() that scan along a compiled
1674        expression for various reasons (e.g. to see if it's fixed length for look
1675        behind). There were bugs in these functions when a repeated \p or \P was
1676        present in the pattern. These operators have additional parameters compared
1677        with \d, etc, and these were not being taken into account when moving along
1678        the compiled data. Specifically:
1679    
1680        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1681            length.
1682    
1683        (b) An item such as \pL+ within a repeated group could cause crashes or
1684            loops.
1685    
1686        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1687            "reference to non-existent subpattern" error.
1688    
1689        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1690    
1691    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1692        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1693    
1694    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1695    
1696    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1697        character were causing crashes (broken optimization).
1698    
1699    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1700        \p or \P) caused a compile-time loop.
1701    
1702    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1703        break. For example, the unstudied pattern [\r\n]A does not match the string
1704        "\r\nA" because change 7.0/46 below moves the current point on by two
1705        characters after failing to match at the start. However, the pattern \nA
1706        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1707        the same is true. There doesn't seem any very clean way out of this, but
1708        what I have chosen to do makes the common cases work: PCRE now takes note
1709        of whether there can be an explicit match for \r or \n anywhere in the
1710        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1711        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1712        pattern has explicit CR or LF references.
1713    
1714    29. Added (*CR) etc for changing newline setting at start of pattern.
1715    
1716    
1717    Version 7.2 19-Jun-07
1718    ---------------------
1719    
1720     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1721        which is apparently normally available under Windows.
1722    
1723     2. Re-jig the pcregrep tests with different newline settings in an attempt
1724        to make them independent of the local environment's newline setting.
1725    
1726     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1727    
1728     4. Some of the "internals" tests were previously cut out when the link size
1729        was not 2, because the output contained actual offsets. The recent new
1730        "Z" feature of pcretest means that these can be cut out, making the tests
1731        usable with all link sizes.
1732    
1733     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1734        stack recursion. This gives a massive performance boost under BSD, but just
1735        a small improvement under Linux. However, it saves one field in the frame
1736        in all cases.
1737    
1738     6. Added more features from the forthcoming Perl 5.10:
1739    
1740        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1741            recursion call. It refers to the nth most recently opened parentheses.
1742    
1743        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1744            to be opened parentheses.
1745    
1746        (c) Conditions that refer to capturing parentheses can be specified
1747            relatively, for example, (?(-2)... or (?(+3)...
1748    
1749        (d) \K resets the start of the current match so that everything before
1750            is not part of it.
1751    
1752        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1753    
1754        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1755            reference syntax.
1756    
1757        (g) (?| introduces a group in which the numbering of parentheses in each
1758            alternative starts with the same number.
1759    
1760        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1761    
1762     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1763        PCRE_INFO_JCHANGED.
1764    
1765     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1766        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1767        for detecting groups that can match an empty string.
1768    
1769     9. A pattern with a very large number of alternatives (more than several
1770        hundred) was running out of internal workspace during the pre-compile
1771        phase, where pcre_compile() figures out how much memory will be needed. A
1772        bit of new cunning has reduced the workspace needed for groups with
1773        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1774        workspace instead of running out of the 4096 that are available.
1775    
1776    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1777    
1778    11. Applied patch from Google to remove an optimization that didn't quite work.
1779        The report of the bug said:
1780    
1781          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1782          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1783          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1784    
1785    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1786        it matched the wrong number of bytes.
1787    
1788    
1789    Version 7.1 24-Apr-07
1790  ---------------------  ---------------------
1791    
1792   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 135  Version 7.1 12-Mar-07 Line 1920  Version 7.1 12-Mar-07
1920      was because its rules for how to advance for /g after matching an empty      was because its rules for how to advance for /g after matching an empty
1921      string at the end of a line did not allow for this case. They now check for      string at the end of a line did not allow for this case. They now check for
1922      it specially.      it specially.
1923    
1924  20. pcretest is supposed to handle patterns and data of any length, by  20. pcretest is supposed to handle patterns and data of any length, by
1925      extending its buffers when necessary. It was getting this wrong when the      extending its buffers when necessary. It was getting this wrong when the
1926      buffer for a data line had to be extended.      buffer for a data line had to be extended.
1927    
1928  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1929      CRLF as a newline sequence.      CRLF as a newline sequence.
1930    
1931    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1932        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1933        I have nevertheless tidied it up.
1934    
1935    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1936    
1937    24. Added a man page for pcre-config.
1938    
1939    
1940  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06

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