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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.30
5    ------------
6    
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
9    
10    2.  Fixed a bug in the code for calculating the fixed length of lookbehind
11        assertions.
12    
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
15    
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
20    
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
25    
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
28    
29    
30    Version 8.21 12-Dec-2011
31    ------------------------
32    
33    1.  Updating the JIT compiler.
34    
35    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
36        are added as well.
37    
38    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
39        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
40        calling _pcre_jit_exec. Some extra comments are added.
41    
42    4.  (*MARK) settings inside atomic groups that do not contain any capturing
43        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
44        was introduced by change 18 for 8.20.
45    
46    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
47        ECMA-262 standard.
48    
49    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
50        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
51        This bug was probably introduced by change 9 of 8.13.
52    
53    7.  While fixing 6 above, I noticed that a number of other items were being
54        incorrectly rejected as "not fixed length". This arose partly because newer
55        opcodes had not been added to the fixed-length checking code. I have (a)
56        corrected the bug and added tests for these items, and (b) arranged for an
57        error to occur if an unknown opcode is encountered while checking for fixed
58        length instead of just assuming "not fixed length". The items that were
59        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
60        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
61        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
62    
63    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
64        being incorrectly compiled and would have given unpredicatble results.
65    
66    9.  A possessively repeated subpattern with minimum repeat count greater than
67        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
68        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
69        the first (A) could occur when it should not.
70    
71    10. Add a cast and remove a redundant test from the code.
72    
73    11. JIT should use pcre_malloc/pcre_free for allocation.
74    
75    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
76        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
77        is anything other than /usr, -L is still shown).
78    
79    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
80    
81    14. Perl does not support \N without a following name in a [] class; PCRE now
82        also gives an error.
83    
84    15. If a forward reference was repeated with an upper limit of around 2000,
85        it caused the error "internal error: overran compiling workspace". The
86        maximum number of forward references (including repeats) was limited by the
87        internal workspace, and dependent on the LINK_SIZE. The code has been
88        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
89        the default depends on LINK_SIZE. There is a new upper limit (for safety)
90        of around 200,000 forward references. While doing this, I also speeded up
91        the filling in of repeated forward references.
92    
93    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
94        incorrectly expecting the subject to contain another "a" after the start.
95    
96    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
97        in the match, the SKIP should be ignored. This was not happening; instead
98        the SKIP was being treated as NOMATCH. For patterns such as
99        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
100        tested.
101    
102    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
103        now much more compatible with Perl, in particular in cases where the result
104        is a non-match for a non-anchored pattern. For example, if
105        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
106        "m", where previously it did not return a name. A side effect of this
107        change is that for partial matches, the last encountered mark name is
108        returned, as for non matches. A number of tests that were previously not
109        Perl-compatible have been moved into the Perl-compatible test files. The
110        refactoring has had the pleasing side effect of removing one argument from
111        the match() function, thus reducing its stack requirements.
112    
113    19. If the /S+ option was used in pcretest to study a pattern using JIT,
114        subsequent uses of /S (without +) incorrectly behaved like /S+.
115    
116    21. Retrieve executable code size support for the JIT compiler and fixing
117        some warnings.
118    
119    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
120        not work when the shorter character appeared right at the end of the
121        subject string.
122    
123    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
124        systems.
125    
126    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
127        output it when the /M option is used in pcretest.
128    
129    25. The CheckMan script was not being included in the distribution. Also, added
130        an explicit "perl" to run Perl scripts from the PrepareRelease script
131        because this is reportedly needed in Windows.
132    
133    26. If study data was being save in a file and studying had not found a set of
134        "starts with" bytes for the pattern, the data written to the file (though
135        never used) was taken from uninitialized memory and so caused valgrind to
136        complain.
137    
138    27. Updated RunTest.bat as provided by Sheri Pierce.
139    
140    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
141    
142    29. Computation of memory usage for the table of capturing group names was
143        giving an unnecessarily large value.
144    
145    
146    Version 8.20 21-Oct-2011
147    ------------------------
148    
149    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
150        a POSIX class. After further experiments with Perl, which convinced me that
151        Perl has bugs and confusions, a closing square bracket is no longer allowed
152        in a POSIX name. This bug also affected patterns with classes that started
153        with full stops.
154    
155    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
156        captured substring, but while checking the failing first alternative,
157        substring 1 is temporarily captured. If the output vector supplied to
158        pcre_exec() was not big enough for this capture, the yield of the function
159        was still zero ("insufficient space for captured substrings"). This cannot
160        be totally fixed without adding another stack variable, which seems a lot
161        of expense for a edge case. However, I have improved the situation in cases
162        such as /(a)(b)x|abc/ matched against "abc", where the return code
163        indicates that fewer than the maximum number of slots in the ovector have
164        been set.
165    
166    3.  Related to (2) above: when there are more back references in a pattern than
167        slots in the output vector, pcre_exec() uses temporary memory during
168        matching, and copies in the captures as far as possible afterwards. It was
169        using the entire output vector, but this conflicts with the specification
170        that only 2/3 is used for passing back captured substrings. Now it uses
171        only the first 2/3, for compatibility. This is, of course, another edge
172        case.
173    
174    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
175        main code base, and can be used by building with --enable-jit. When this is
176        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
177        runtime --no-jit option is given.
178    
179    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
180        ovector, the return from the function was zero, implying that there were
181        other matches that did not fit. The correct "exactly full" value is now
182        returned.
183    
184    6.  If a subpattern that was called recursively or as a subroutine contained
185        (*PRUNE) or any other control that caused it to give a non-standard return,
186        invalid errors such as "Error -26 (nested recursion at the same subject
187        position)" or even infinite loops could occur.
188    
189    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
190        computing the minimum length on reaching *ACCEPT, and so ended up with the
191        wrong value of 1 rather than 0. Further investigation indicates that
192        computing a minimum subject length in the presence of *ACCEPT is difficult
193        (think back references, subroutine calls), and so I have changed the code
194        so that no minimum is registered for a pattern that contains *ACCEPT.
195    
196    8.  If (*THEN) was present in the first (true) branch of a conditional group,
197        it was not handled as intended. [But see 16 below.]
198    
199    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
200        Sheri Pierce.
201    
202    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
203        the first byte in a match must be "a".
204    
205    11. Change 17 for 8.13 increased the recursion depth for patterns like
206        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
207        pattern contains any instances of (*THEN). If it does not, the old
208        optimizations are restored. It would be nice to do this on a per-group
209        basis, but at the moment that is not feasible.
210    
211    12. In some environments, the output of pcretest -C is CRLF terminated. This
212        broke RunTest's code that checks for the link size. A single white space
213        character after the value is now allowed for.
214    
215    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
216        For "fr", it uses the Windows-specific input and output files.
217    
218    14. If (*THEN) appeared in a group that was called recursively or as a
219        subroutine, it did not work as intended. [But see next item.]
220    
221    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
222        pattern fragments (but not containing any | characters). If A and B are
223        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
224        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
225        D. In other words, Perl considers parentheses that do not contain any |
226        characters to be part of a surrounding alternative, whereas PCRE was
227        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
228        differently. PCRE now behaves in the same way as Perl, except in the case
229        of subroutine/recursion calls such as (?1) which have in any case always
230        been different (but PCRE had them first :-).
231    
232    16. Related to 15 above: Perl does not treat the | in a conditional group as
233        creating alternatives. Such a group is treated in the same way as an
234        ordinary group without any | characters when processing (*THEN). PCRE has
235        been changed to match Perl's behaviour.
236    
237    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
238        RunGrepTest script failed.
239    
240    18. Change 22 for version 13 caused atomic groups to use more stack. This is
241        inevitable for groups that contain captures, but it can lead to a lot of
242        stack use in large patterns. The old behaviour has been restored for atomic
243        groups that do not contain any capturing parentheses.
244    
245    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
246        suppress the check for a minimum subject length at run time. (If it was
247        given to pcre_exec() or pcre_dfa_exec() it did work.)
248    
249    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
250        fail to work when decoding hex characters in data strings in EBCDIC
251        environments.
252    
253    21. It appears that in at least one Mac OS environment, the isxdigit() function
254        is implemented as a macro that evaluates to its argument more than once,
255        contravening the C 90 Standard (I haven't checked a later standard). There
256        was an instance in pcretest which caused it to go wrong when processing
257        \x{...} escapes in subject strings. The has been rewritten to avoid using
258        things like p++ in the argument of isxdigit().
259    
260    
261    Version 8.13 16-Aug-2011
262    ------------------------
263    
264    1.  The Unicode data tables have been updated to Unicode 6.0.0.
265    
266    2.  Two minor typos in pcre_internal.h have been fixed.
267    
268    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
269        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
270        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
271    
272    4.  There were a number of related bugs in the code for matching backrefences
273        caselessly in UTF-8 mode when codes for the characters concerned were
274        different numbers of bytes. For example, U+023A and U+2C65 are an upper
275        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
276        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
277        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
278        2-byte code at the end of the subject (it thought there wasn't enough data
279        left).
280    
281    5.  Comprehensive information about what went wrong is now returned by
282        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
283        as the output vector has at least 2 elements. The offset of the start of
284        the failing character and a reason code are placed in the vector.
285    
286    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
287        now returned is for the first byte of the failing character, instead of the
288        last byte inspected. This is an incompatible change, but I hope it is small
289        enough not to be a problem. It makes the returned offset consistent with
290        pcre_exec() and pcre_dfa_exec().
291    
292    7.  pcretest now gives a text phrase as well as the error number when
293        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
294        failure, the offset and reason code are output.
295    
296    8.  When \R was used with a maximizing quantifier it failed to skip backwards
297        over a \r\n pair if the subsequent match failed. Instead, it just skipped
298        back over a single character (\n). This seems wrong (because it treated the
299        two characters as a single entity when going forwards), conflicts with the
300        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
301        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
302        has been changed.
303    
304    9.  Some internal refactoring has changed the processing so that the handling
305        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
306        time (the PCRE_DOTALL option was changed this way some time ago: version
307        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
308        which was always a bit of a fudge. It also means that there is one less
309        argument for the match() function, which reduces its stack requirements
310        slightly. This change also fixes an incompatibility with Perl: the pattern
311        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
312    
313    10. More internal refactoring has drastically reduced the number of recursive
314        calls to match() for possessively repeated groups such as (abc)++ when
315        using pcre_exec().
316    
317    11. While implementing 10, a number of bugs in the handling of groups were
318        discovered and fixed:
319    
320        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
321        (a|)*(?1) gave a compile-time internal error.
322        ((a|)+)+  did not notice that the outer group could match an empty string.
323        (^a|^)+   was not marked as anchored.
324        (.*a|.*)+ was not marked as matching at start or after a newline.
325    
326    12. Yet more internal refactoring has removed another argument from the match()
327        function. Special calls to this function are now indicated by setting a
328        value in a variable in the "match data" data block.
329    
330    13. Be more explicit in pcre_study() instead of relying on "default" for
331        opcodes that mean there is no starting character; this means that when new
332        ones are added and accidentally left out of pcre_study(), testing should
333        pick them up.
334    
335    14. The -s option of pcretest has been documented for ages as being an old
336        synonym of -m (show memory usage). I have changed it to mean "force study
337        for every regex", that is, assume /S for every regex. This is similar to -i
338        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
339        using it. It makes it easier to run collections of tests with and without
340        study enabled, and thereby test pcre_study() more easily. All the standard
341        tests are now run with and without -s (but some patterns can be marked as
342        "never study" - see 20 below).
343    
344    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
345        restoration of the capturing data to the outer values was not happening
346        correctly.
347    
348    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
349        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
350        pattern had matched an empty string, and so incorrectly returned a no
351        match.
352    
353    17. There was optimizing code for the last branch of non-capturing parentheses,
354        and also for the obeyed branch of a conditional subexpression, which used
355        tail recursion to cut down on stack usage. Unfortunately, now that there is
356        the possibility of (*THEN) occurring in these branches, tail recursion is
357        no longer possible because the return has to be checked for (*THEN). These
358        two optimizations have therefore been removed. [But see 8.20/11 above.]
359    
360    18. If a pattern containing \R was studied, it was assumed that \R always
361        matched two bytes, thus causing the minimum subject length to be
362        incorrectly computed because \R can also match just one byte.
363    
364    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
365        was incorrectly computed.
366    
367    20. If /S is present twice on a test pattern in pcretest input, it now
368        *disables* studying, thereby overriding the use of -s on the command line
369        (see 14 above). This is necessary for one or two tests to keep the output
370        identical in both cases.
371    
372    21. When (*ACCEPT) was used in an assertion that matched an empty string and
373        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
374    
375    22. When an atomic group that contained a capturing parenthesis was
376        successfully matched, but the branch in which it appeared failed, the
377        capturing was not being forgotten if a higher numbered group was later
378        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
379        group 1 to "a", when in fact it should be unset. This applied to multi-
380        branched capturing and non-capturing groups, repeated or not, and also to
381        positive assertions (capturing in negative assertions does not happen
382        in PCRE) and also to nested atomic groups.
383    
384    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
385        subject after a captured substring, to make it easier to tell which of a
386        number of identical substrings has been captured.
387    
388    24. The way atomic groups are processed by pcre_exec() has been changed so that
389        if they are repeated, backtracking one repetition now resets captured
390        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
391        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
392        "aaa". Previously, it would have been "a". As part of this code
393        refactoring, the way recursive calls are handled has also been changed.
394    
395    25. If an assertion condition captured any substrings, they were not passed
396        back unless some other capturing happened later. For example, if
397        (?(?=(a))a) was matched against "a", no capturing was returned.
398    
399    26. When studying a pattern that contained subroutine calls or assertions,
400        the code for finding the minimum length of a possible match was handling
401        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
402        group 1 called group 2 while simultaneously a separate group 2 called group
403        1). A stack overflow occurred in this case. I have fixed this by limiting
404        the recursion depth to 10.
405    
406    27. Updated RunTest.bat in the distribution to the version supplied by Tom
407        Fortmann. This supports explicit test numbers on the command line, and has
408        argument validation and error reporting.
409    
410    28. An instance of \X with an unlimited repeat could fail if at any point the
411        first character it looked at was a mark character.
412    
413    29. Some minor code refactoring concerning Unicode properties and scripts
414        should reduce the stack requirement of match() slightly.
415    
416    30. Added the '=' option to pcretest to check the setting of unused capturing
417        slots at the end of the pattern, which are documented as being -1, but are
418        not included in the return count.
419    
420    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
421        compiled something random. Now it gives a compile-time error (as does
422        Perl).
423    
424    32. A *MARK encountered during the processing of a positive assertion is now
425        recorded and passed back (compatible with Perl).
426    
427    33. If --only-matching or --colour was set on a pcregrep call whose pattern
428        had alternative anchored branches, the search for a second match in a line
429        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
430        matched the line "0102" twice. The same bug affected patterns that started
431        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
432        twice.
433    
434    34. Previously, PCRE did not allow quantification of assertions. However, Perl
435        does, and because of capturing effects, quantifying parenthesized
436        assertions may at times be useful. Quantifiers are now allowed for
437        parenthesized assertions.
438    
439    35. A minor code tidy in pcre_compile() when checking options for \R usage.
440    
441    36. \g was being checked for fancy things in a character class, when it should
442        just be a literal "g".
443    
444    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
445        appearance of a nested POSIX class supersedes an apparent external class.
446        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
447        unescaped square brackets may also appear as part of class names. For
448        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
449        more like Perl. (But see 8.20/1 above.)
450    
451    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
452        was because it thought it was \N{name}, which is not supported).
453    
454    39. Add minix to OS list not supporting the -S option in pcretest.
455    
456    40. PCRE tries to detect cases of infinite recursion at compile time, but it
457        cannot analyze patterns in sufficient detail to catch mutual recursions
458        such as ((?1))((?2)). There is now a runtime test that gives an error if a
459        subgroup is called recursively as a subpattern for a second time at the
460        same position in the subject string. In previous releases this might have
461        been caught by the recursion limit, or it might have run out of stack.
462    
463    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
464        happen only once. PCRE was, however incorrectly giving a compile time error
465        "recursive call could loop indefinitely" because it cannot analyze the
466        pattern in sufficient detail. The compile time test no longer happens when
467        PCRE is compiling a conditional subpattern, but actual runaway loops are
468        now caught at runtime (see 40 above).
469    
470    42. It seems that Perl allows any characters other than a closing parenthesis
471        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
472        has been changed to be the same.
473    
474    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
475        as not to get warnings when autogen.sh is called. Also changed
476        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
477    
478    44. To help people who use pcregrep to scan files containing exceedingly long
479        lines, the following changes have been made:
480    
481        (a) The default value of the buffer size parameter has been increased from
482            8K to 20K. (The actual buffer used is three times this size.)
483    
484        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
485            PCRE is built.
486    
487        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
488            to be set at run time.
489    
490        (d) Numerical values in pcregrep options can be followed by K or M, for
491            example --buffer-size=50K.
492    
493        (e) If a line being scanned overflows pcregrep's buffer, an error is now
494            given and the return code is set to 2.
495    
496    45. Add a pointer to the latest mark to the callout data block.
497    
498    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
499        partial match of an empty string instead of no match. This was specific to
500        the use of ".".
501    
502    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
503        complete match instead of a partial match. This bug was dependent on both
504        the PCRE_UTF8 and PCRE_DOTALL options being set.
505    
506    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
507        starting byte set, because \b was not being ignored.
508    
509    
510    Version 8.12 15-Jan-2011
511    ------------------------
512    
513    1.  Fixed some typos in the markup of the man pages, and wrote a script that
514        checks for such things as part of the documentation building process.
515    
516    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
517        --match-limit and --recursion-limit options (added for 8.11). In
518        particular, this made one of the standard tests fail. (The integer value
519        went into the wrong half of a long int.)
520    
521    3.  If the --colour option was given to pcregrep with -v (invert match), it
522        did strange things, either producing crazy output, or crashing. It should,
523        of course, ignore a request for colour when reporting lines that do not
524        match.
525    
526    4.  Another pcregrep bug caused similar problems if --colour was specified with
527        -M (multiline) and the pattern match finished with a line ending.
528    
529    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
530        matched in multiline mode, the following line was shown as part of the
531        match. This seems wrong, so I have changed it.
532    
533    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
534        the check for further matches in the same line (so they could be coloured)
535        to overrun the end of the current line. If another match was found, it was
536        incorrectly shown (and then shown again when found in the next line).
537    
538    7.  If pcregrep was compiled under Windows, there was a reference to the
539        function pcregrep_exit() before it was defined. I am assuming this was
540        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
541        reported by a user. I've moved the definition above the reference.
542    
543    
544    Version 8.11 10-Dec-2010
545    ------------------------
546    
547    1.  (*THEN) was not working properly if there were untried alternatives prior
548        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
549        backtracked to try for "b" instead of moving to the next alternative branch
550        at the same level (in this case, to look for "c"). The Perl documentation
551        is clear that when (*THEN) is backtracked onto, it goes to the "next
552        alternative in the innermost enclosing group".
553    
554    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
555        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
556        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
557        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
558        (*THEN).
559    
560    3.  If \s appeared in a character class, it removed the VT character from
561        the class, even if it had been included by some previous item, for example
562        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
563        of \s, but is part of the POSIX "space" class.)
564    
565    4.  A partial match never returns an empty string (because you can always
566        match an empty string at the end of the subject); however the checking for
567        an empty string was starting at the "start of match" point. This has been
568        changed to the "earliest inspected character" point, because the returned
569        data for a partial match starts at this character. This means that, for
570        example, /(?<=abc)def/ gives a partial match for the subject "abc"
571        (previously it gave "no match").
572    
573    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
574        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
575        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
576        has an implication that the given string is incomplete (because a partial
577        match is preferred over a full match). For this reason, these items now
578        give a partial match in this situation. [Aside: previously, the one case
579        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
580        match rather than a full match, which was wrong by the old rules, but is
581        now correct.]
582    
583    6.  There was a bug in the handling of #-introduced comments, recognized when
584        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
585        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
586        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
587        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
588        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
589        places in pcre_compile().
590    
591    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
592        comments when looking ahead for named forward references to subpatterns,
593        the only newline sequence it recognized was NL. It now handles newlines
594        according to the set newline convention.
595    
596    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
597        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
598        cater for a lack of strerror(). These oversights have been fixed.
599    
600    9.  Added --match-limit and --recursion-limit to pcregrep.
601    
602    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
603    
604    11. When the -o option was used, pcregrep was setting a return code of 1, even
605        when matches were found, and --line-buffered was not being honoured.
606    
607    12. Added an optional parentheses number to the -o and --only-matching options
608        of pcregrep.
609    
610    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
611        can match an empty string. The code to do it in pcretest and pcredemo
612        needed fixing:
613    
614        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
615            only one byte after an empty string match just before CRLF (this case
616            just got forgotten; "any" and "anycrlf" were OK).
617    
618        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
619            mode when an empty string match preceded an ASCII character followed by
620            a non-ASCII character. (The code for advancing by one character rather
621            than one byte was nonsense.)
622    
623        (c) The pcredemo.c sample program did not have any code at all to handle
624            the cases when CRLF is a valid newline sequence.
625    
626    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
627        as a starting offset was within the subject string. There is now a new
628        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
629        negative or greater than the length of the string. In order to test this,
630        pcretest is extended to allow the setting of negative starting offsets.
631    
632    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
633        starting offset points to the beginning of a UTF-8 character was
634        unnecessarily clumsy. I tidied it up.
635    
636    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
637        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
638    
639    17. Nobody had reported that the --include_dir option, which was added in
640        release 7.7 should have been called --include-dir (hyphen, not underscore)
641        for compatibility with GNU grep. I have changed it to --include-dir, but
642        left --include_dir as an undocumented synonym, and the same for
643        --exclude-dir, though that is not available in GNU grep, at least as of
644        release 2.5.4.
645    
646    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
647        characters from a string of bytes) have been redefined so as not to use
648        loops, in order to improve performance in some environments. At the same
649        time, I abstracted some of the common code into auxiliary macros to save
650        repetition (this should not affect the compiled code).
651    
652    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
653        compile-time error is now given if \c is not followed by an ASCII
654        character, that is, a byte less than 128. (In EBCDIC mode, the code is
655        different, and any byte value is allowed.)
656    
657    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
658        START_OPTIMIZE option, which is now allowed at compile time - but just
659        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
660        to pcregrep and other applications that have no direct access to PCRE
661        options. The new /Y option in pcretest sets this option when calling
662        pcre_compile().
663    
664    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
665        back references. Groups containing recursive back references were forced to
666        be atomic by that change, but in the case of named groups, the amount of
667        memory required was incorrectly computed, leading to "Failed: internal
668        error: code overflow". This has been fixed.
669    
670    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
671        pcretest.c, to avoid build problems in some Borland environments.
672    
673    
674    Version 8.10 25-Jun-2010
675    ------------------------
676    
677    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
678        THEN.
679    
680    2.  (*ACCEPT) was not working when inside an atomic group.
681    
682    3.  Inside a character class, \B is treated as a literal by default, but
683        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
684        causes the error). The code is unchanged, but I tidied the documentation.
685    
686    4.  Inside a character class, PCRE always treated \R and \X as literals,
687        whereas Perl faults them if its -w option is set. I have changed PCRE so
688        that it faults them when PCRE_EXTRA is set.
689    
690    5.  Added support for \N, which always matches any character other than
691        newline. (It is the same as "." when PCRE_DOTALL is not set.)
692    
693    6.  When compiling pcregrep with newer versions of gcc which may have
694        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
695        declared with attribute warn_unused_result" were given. Just casting the
696        result to (void) does not stop the warnings; a more elaborate fudge is
697        needed. I've used a macro to implement this.
698    
699    7.  Minor change to pcretest.c to avoid a compiler warning.
700    
701    8.  Added four artifical Unicode properties to help with an option to make
702        \s etc use properties (see next item). The new properties are: Xan
703        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
704    
705    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
706        use Unicode properties. (*UCP) at the start of a pattern can be used to set
707        this option. Modified pcretest to add /W to test this facility. Added
708        REG_UCP to make it available via the POSIX interface.
709    
710    10. Added --line-buffered to pcregrep.
711    
712    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
713        studied, and the match started with a letter with a code point greater than
714        127 whose first byte was different to the first byte of the other case of
715        the letter, the other case of this starting letter was not recognized
716        (#976).
717    
718    12. If a pattern that was studied started with a repeated Unicode property
719        test, for example, \p{Nd}+, there was the theoretical possibility of
720        setting up an incorrect bitmap of starting bytes, but fortunately it could
721        not have actually happened in practice until change 8 above was made (it
722        added property types that matched character-matching opcodes).
723    
724    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
725        possible starting bytes for non-anchored patterns.
726    
727    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
728        \R, and also a number of cases that involve Unicode properties, both
729        explicit and implicit when PCRE_UCP is set.
730    
731    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
732        input, it could crash or give wrong results if characters with values
733        greater than 0xc0 were present in the subject string. (Detail: it assumed
734        UTF-8 input when processing these items.)
735    
736    16. Added a lot of (int) casts to avoid compiler warnings in systems where
737        size_t is 64-bit (#991).
738    
739    17. Added a check for running out of memory when PCRE is compiled with
740        --disable-stack-for-recursion (#990).
741    
742    18. If the last data line in a file for pcretest does not have a newline on
743        the end, a newline was missing in the output.
744    
745    19. The default pcre_chartables.c file recognizes only ASCII characters (values
746        less than 128) in its various bitmaps. However, there is a facility for
747        generating tables according to the current locale when PCRE is compiled. It
748        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
749        characters, are recognized by isspace() and therefore were getting set in
750        these tables, and indeed these tables seem to approximate to ISO 8859. This
751        caused a problem in UTF-8 mode when pcre_study() was used to create a list
752        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
753        which of course cannot start UTF-8 characters. I have changed the code so
754        that only real ASCII characters (less than 128) and the correct starting
755        bytes for UTF-8 encodings are set for characters greater than 127 when in
756        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
757        altogether.)
758    
759    20. Added the /T option to pcretest so as to be able to run tests with non-
760        standard character tables, thus making it possible to include the tests
761        used for 19 above in the standard set of tests.
762    
763    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
764        reference to a subpattern the other side of a comment that contains an
765        opening parenthesis caused either an internal compiling error, or a
766        reference to the wrong subpattern.
767    
768    
769    Version 8.02 19-Mar-2010
770    ------------------------
771    
772    1.  The Unicode data tables have been updated to Unicode 5.2.0.
773    
774    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
775        configured.
776    
777    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
778        original author of that file, following a query about its status.
779    
780    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
781        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
782    
783    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
784        quantifier applied to a forward-referencing subroutine call, could compile
785        incorrect code or give the error "internal error: previously-checked
786        referenced subpattern not found".
787    
788    6.  Both MS Visual Studio and Symbian OS have problems with initializing
789        variables to point to external functions. For these systems, therefore,
790        pcre_malloc etc. are now initialized to local functions that call the
791        relevant global functions.
792    
793    7.  There were two entries missing in the vectors called coptable and poptable
794        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
795        I've fixed the data, and added a kludgy way of testing at compile time that
796        the lengths are correct (equal to the number of opcodes).
797    
798    8.  Following on from 7, I added a similar kludge to check the length of the
799        eint vector in pcreposix.c.
800    
801    9.  Error texts for pcre_compile() are held as one long string to avoid too
802        much relocation at load time. To find a text, the string is searched,
803        counting zeros. There was no check for running off the end of the string,
804        which could happen if a new error number was added without updating the
805        string.
806    
807    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
808    
809    11. \K was not working if it appeared in an atomic group or in a group that
810        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
811        \K is "not well defined" if used in an assertion. PCRE now accepts it if
812        the assertion is positive, but not if it is negative.
813    
814    12. Change 11 fortuitously reduced the size of the stack frame used in the
815        "match()" function of pcre_exec.c by one pointer. Forthcoming
816        implementation of support for (*MARK) will need an extra pointer on the
817        stack; I have reserved it now, so that the stack frame size does not
818        decrease.
819    
820    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
821        item in branch that calls a recursion is a subroutine call - as in the
822        second branch in the above example - was incorrectly given the compile-
823        time error "recursive call could loop indefinitely" because pcre_compile()
824        was not correctly checking the subroutine for matching a non-empty string.
825    
826    14. The checks for overrunning compiling workspace could trigger after an
827        overrun had occurred. This is a "should never occur" error, but it can be
828        triggered by pathological patterns such as hundreds of nested parentheses.
829        The checks now trigger 100 bytes before the end of the workspace.
830    
831    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
832    
833    
834    Version 8.01 19-Jan-2010
835    ------------------------
836    
837    1.  If a pattern contained a conditional subpattern with only one branch (in
838        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
839        computed the wrong minimum data length (which is of course zero for such
840        subpatterns). This could cause incorrect "no match" results.
841    
842    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
843        the pattern is reset in the first branch, pcre_compile() failed with
844        "internal error: code overflow at offset...". This happened only when
845        the reset was to the original external option setting. (An optimization
846        abstracts leading options settings into an external setting, which was the
847        cause of this.)
848    
849    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
850        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
851        assertion pattern did not match (meaning that the assertion was true), it
852        was incorrectly treated as false if the SKIP had been reached during the
853        matching. This also applied to assertions used as conditions.
854    
855    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
856        assertion subpattern, including such a pattern used as a condition,
857        unpredictable results occurred, instead of the error return
858        PCRE_ERROR_DFA_UITEM.
859    
860    5.  The C++ GlobalReplace function was not working like Perl for the special
861        situation when an empty string is matched. It now does the fancy magic
862        stuff that is necessary.
863    
864    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
865        removed. (These were left over from very, very early versions of PCRE.)
866    
867    7.  Some cosmetic changes to the code to make life easier when compiling it
868        as part of something else:
869    
870        (a) Change DEBUG to PCRE_DEBUG.
871    
872        (b) In pcre_compile(), rename the member of the "branch_chain" structure
873            called "current" as "current_branch", to prevent a collision with the
874            Linux macro when compiled as a kernel module.
875    
876        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
877            prevent a collision with the Linux macro when compiled as a kernel
878            module.
879    
880    8.  In pcre_compile() there are some checks for integer overflows that used to
881        cast potentially large values to (double). This has been changed to that
882        when building, a check for int64_t is made, and if it is found, it is used
883        instead, thus avoiding the use of floating point arithmetic. (There is no
884        other use of FP in PCRE.) If int64_t is not found, the fallback is to
885        double.
886    
887    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
888        2005 (difference between two addresses compared to an unsigned value).
889    
890    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
891        custom one, because of the following reported problem in Windows:
892    
893          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
894              under Win32.
895          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
896              therefore missing the function definition.
897          - The compiler thus generates a "C" signature for the test function.
898          - The linker fails to find the "C" function.
899          - PCRE fails to configure if asked to do so against libbz2.
900    
901    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
902        messages were output:
903    
904          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
905          rerunning libtoolize, to keep the correct libtool macros in-tree.
906          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
907    
908        I have done both of these things.
909    
910    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
911        most of the time, it *can* run out if it is given a pattern that contains a
912        runaway infinite recursion. I updated the discussion in the pcrestack man
913        page.
914    
915    13. Now that we have gone to the x.xx style of version numbers, the minor
916        version may start with zero. Using 08 or 09 is a bad idea because users
917        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
918        interpreted as invalid octal numbers. I've updated the previous comment in
919        configure.ac, and also added a check that gives an error if 08 or 09 are
920        used.
921    
922    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
923        causing partial matching to fail when the end of the subject matched \W
924        in a UTF-8 pattern where \W was quantified with a minimum of 3.
925    
926    15. There were some discrepancies between the declarations in pcre_internal.h
927        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
928        their definitions. The declarations used "const uschar *" and the
929        definitions used USPTR. Even though USPTR is normally defined as "const
930        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
931        reported that: "This difference in casting confuses some C++ compilers, for
932        example, SunCC recognizes above declarations as different functions and
933        generates broken code for hbpcre." I have changed the declarations to use
934        USPTR.
935    
936    16. GNU libtool is named differently on some systems. The autogen.sh script now
937        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
938        (FreeBSD).
939    
940    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
941        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
942        comment: "Figure out how to create a longlong from a string: strtoll and
943        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
944        instance, but it only takes 2 args instead of 3!"
945    
946    18. A subtle bug concerned with back references has been fixed by a change of
947        specification, with a corresponding code fix. A pattern such as
948        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
949        refers, was giving matches when it shouldn't. For example, xa=xaaa would
950        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
951        same bug. Such groups have to be quantified to be useful, or contained
952        inside another quantified group. (If there's no repetition, the reference
953        can never match.) The problem arises because, having left the group and
954        moved on to the rest of the pattern, a later failure that backtracks into
955        the group uses the captured value from the final iteration of the group
956        rather than the correct earlier one. I have fixed this in PCRE by forcing
957        any group that contains a reference to itself to be an atomic group; that
958        is, there cannot be any backtracking into it once it has completed. This is
959        similar to recursive and subroutine calls.
960    
961    
962    Version 8.00 19-Oct-09
963    ----------------------
964    
965    1.  The table for translating pcre_compile() error codes into POSIX error codes
966        was out-of-date, and there was no check on the pcre_compile() error code
967        being within the table. This could lead to an OK return being given in
968        error.
969    
970    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
971        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
972        in a Windows environment.
973    
974    3.  The pcregrep --count option prints the count for each file even when it is
975        zero, as does GNU grep. However, pcregrep was also printing all files when
976        --files-with-matches was added. Now, when both options are given, it prints
977        counts only for those files that have at least one match. (GNU grep just
978        prints the file name in this circumstance, but including the count seems
979        more useful - otherwise, why use --count?) Also ensured that the
980        combination -clh just lists non-zero counts, with no names.
981    
982    4.  The long form of the pcregrep -F option was incorrectly implemented as
983        --fixed_strings instead of --fixed-strings. This is an incompatible change,
984        but it seems right to fix it, and I didn't think it was worth preserving
985        the old behaviour.
986    
987    5.  The command line items --regex=pattern and --regexp=pattern were not
988        recognized by pcregrep, which required --regex pattern or --regexp pattern
989        (with a space rather than an '='). The man page documented the '=' forms,
990        which are compatible with GNU grep; these now work.
991    
992    6.  No libpcreposix.pc file was created for pkg-config; there was just
993        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
994    
995    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
996        when UCP support is not needed, by modifying the Python script that
997        generates it from Unicode data files. This should not matter if the module
998        is correctly used as a library, but I received one complaint about 50K of
999        unwanted data. My guess is that the person linked everything into his
1000        program rather than using a library. Anyway, it does no harm.
1001    
1002    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1003        was a minimum greater than 1 for a wide character in a possessive
1004        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1005        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1006        character. Chaos in the form of incorrect output or a compiling loop could
1007        result.
1008    
1009    9.  The restrictions on what a pattern can contain when partial matching is
1010        requested for pcre_exec() have been removed. All patterns can now be
1011        partially matched by this function. In addition, if there are at least two
1012        slots in the offset vector, the offset of the earliest inspected character
1013        for the match and the offset of the end of the subject are set in them when
1014        PCRE_ERROR_PARTIAL is returned.
1015    
1016    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1017        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1018        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1019        and may be more useful for multi-segment matching.
1020    
1021    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1022        used to be given if ever the end of the subject was reached; now it is
1023        given only if matching could not proceed because another character was
1024        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1025        string "Z", which now yields "no match" instead of "partial match". In the
1026        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1027        final character ended with (*FAIL).
1028    
1029    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1030        if the pattern had a "must contain" character that was already found in the
1031        earlier partial match, unless partial matching was again requested. For
1032        example, with the pattern /dog.(body)?/, the "must contain" character is
1033        "g". If the first part-match was for the string "dog", restarting with
1034        "sbody" failed. This bug has been fixed.
1035    
1036    13. The string returned by pcre_dfa_exec() after a partial match has been
1037        changed so that it starts at the first inspected character rather than the
1038        first character of the match. This makes a difference only if the pattern
1039        starts with a lookbehind assertion or \b or \B (\K is not supported by
1040        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1041        matching functions compatible, and I think it's the right thing to do.
1042    
1043    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1044        so that the demonstration program is easily available in environments where
1045        PCRE has not been installed from source.
1046    
1047    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1048        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1049        library.
1050    
1051    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1052        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1053        is not the first non-POSIX option to be added. Clearly some people find
1054        these options useful.
1055    
1056    17. If a caller to the POSIX matching function regexec() passes a non-zero
1057        value for nmatch with a NULL value for pmatch, the value of
1058        nmatch is forced to zero.
1059    
1060    18. RunGrepTest did not have a test for the availability of the -u option of
1061        the diff command, as RunTest does. It now checks in the same way as
1062        RunTest, and also checks for the -b option.
1063    
1064    19. If an odd number of negated classes containing just a single character
1065        interposed, within parentheses, between a forward reference to a named
1066        subpattern and the definition of the subpattern, compilation crashed with
1067        an internal error, complaining that it could not find the referenced
1068        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1069        [The bug was that it was starting one character too far in when skipping
1070        over the character class, thus treating the ] as data rather than
1071        terminating the class. This meant it could skip too much.]
1072    
1073    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1074        /g option in pcretest when the pattern contains \K, which makes it possible
1075        to have an empty string match not at the start, even when the pattern is
1076        anchored. Updated pcretest and pcredemo to use this option.
1077    
1078    21. If the maximum number of capturing subpatterns in a recursion was greater
1079        than the maximum at the outer level, the higher number was returned, but
1080        with unset values at the outer level. The correct (outer level) value is
1081        now given.
1082    
1083    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1084        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1085        make it do so. The string so far is captured, making this feature
1086        compatible with Perl.
1087    
1088    23. The tests have been re-organized, adding tests 11 and 12, to make it
1089        possible to check the Perl 5.10 features against Perl 5.10.
1090    
1091    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1092        pattern matches a fixed length string. PCRE did not allow this; now it
1093        does. Neither allows recursion.
1094    
1095    25. I finally figured out how to implement a request to provide the minimum
1096        length of subject string that was needed in order to match a given pattern.
1097        (It was back references and recursion that I had previously got hung up
1098        on.) This code has now been added to pcre_study(); it finds a lower bound
1099        to the length of subject needed. It is not necessarily the greatest lower
1100        bound, but using it to avoid searching strings that are too short does give
1101        some useful speed-ups. The value is available to calling programs via
1102        pcre_fullinfo().
1103    
1104    26. While implementing 25, I discovered to my embarrassment that pcretest had
1105        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1106        study optimizations had never been tested with that matching function.
1107        Oops. What is worse, even when it was passed study data, there was a bug in
1108        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1109        were also very few tests of studied patterns with pcre_dfa_exec().
1110    
1111    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1112        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1113        on the other side of the coin, they are no longer allowed to have different
1114        names, because these cannot be distinguished in PCRE, and this has caused
1115        confusion. (This is a difference from Perl.)
1116    
1117    28. When duplicate subpattern names are present (necessarily with different
1118        numbers, as required by 27 above), and a test is made by name in a
1119        conditional pattern, either for a subpattern having been matched, or for
1120        recursion in such a pattern, all the associated numbered subpatterns are
1121        tested, and the overall condition is true if the condition is true for any
1122        one of them. This is the way Perl works, and is also more like the way
1123        testing by number works.
1124    
1125    
1126  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1127  ---------------------  ---------------------
1128    
# Line 112  Version 7.9 11-Apr-09 Line 1234  Version 7.9 11-Apr-09
1234    
1235  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
1236      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
1237    
1238  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1239      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
1240      pre-defined.      pre-defined.
1241    
1242  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
1243    
1244  29. Arrange for flags added by the "release type" setting in CMake to be shown  29. Arrange for flags added by the "release type" setting in CMake to be shown
1245      in the configuration summary.      in the configuration summary.

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