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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.11 10-Oct-2010  Version 8.21
5    ------------
6    
7    1.  Updating the JIT compiler.
8    
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
11    
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
15    
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
19    
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
26    
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
36    
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
39    
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
44    
45    10. Add a cast and remove a redundant test from the code.
46    
47    11. JIT should use pcre_malloc/pcre_free for allocation.
48    
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
52    
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
54    
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
57    
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
61    
62    
63    Version 8.20 21-Oct-2011
64    ------------------------
65    
66    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
67        a POSIX class. After further experiments with Perl, which convinced me that
68        Perl has bugs and confusions, a closing square bracket is no longer allowed
69        in a POSIX name. This bug also affected patterns with classes that started
70        with full stops.
71    
72    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
73        captured substring, but while checking the failing first alternative,
74        substring 1 is temporarily captured. If the output vector supplied to
75        pcre_exec() was not big enough for this capture, the yield of the function
76        was still zero ("insufficient space for captured substrings"). This cannot
77        be totally fixed without adding another stack variable, which seems a lot
78        of expense for a edge case. However, I have improved the situation in cases
79        such as /(a)(b)x|abc/ matched against "abc", where the return code
80        indicates that fewer than the maximum number of slots in the ovector have
81        been set.
82    
83    3.  Related to (2) above: when there are more back references in a pattern than
84        slots in the output vector, pcre_exec() uses temporary memory during
85        matching, and copies in the captures as far as possible afterwards. It was
86        using the entire output vector, but this conflicts with the specification
87        that only 2/3 is used for passing back captured substrings. Now it uses
88        only the first 2/3, for compatibility. This is, of course, another edge
89        case.
90    
91    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
92        main code base, and can be used by building with --enable-jit. When this is
93        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
94        runtime --no-jit option is given.
95    
96    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
97        ovector, the return from the function was zero, implying that there were
98        other matches that did not fit. The correct "exactly full" value is now
99        returned.
100    
101    6.  If a subpattern that was called recursively or as a subroutine contained
102        (*PRUNE) or any other control that caused it to give a non-standard return,
103        invalid errors such as "Error -26 (nested recursion at the same subject
104        position)" or even infinite loops could occur.
105    
106    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
107        computing the minimum length on reaching *ACCEPT, and so ended up with the
108        wrong value of 1 rather than 0. Further investigation indicates that
109        computing a minimum subject length in the presence of *ACCEPT is difficult
110        (think back references, subroutine calls), and so I have changed the code
111        so that no minimum is registered for a pattern that contains *ACCEPT.
112    
113    8.  If (*THEN) was present in the first (true) branch of a conditional group,
114        it was not handled as intended. [But see 16 below.]
115    
116    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
117        Sheri Pierce.
118    
119    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
120        the first byte in a match must be "a".
121    
122    11. Change 17 for 8.13 increased the recursion depth for patterns like
123        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
124        pattern contains any instances of (*THEN). If it does not, the old
125        optimizations are restored. It would be nice to do this on a per-group
126        basis, but at the moment that is not feasible.
127    
128    12. In some environments, the output of pcretest -C is CRLF terminated. This
129        broke RunTest's code that checks for the link size. A single white space
130        character after the value is now allowed for.
131    
132    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
133        For "fr", it uses the Windows-specific input and output files.
134    
135    14. If (*THEN) appeared in a group that was called recursively or as a
136        subroutine, it did not work as intended. [But see next item.]
137    
138    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
139        pattern fragments (but not containing any | characters). If A and B are
140        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
141        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
142        D. In other words, Perl considers parentheses that do not contain any |
143        characters to be part of a surrounding alternative, whereas PCRE was
144        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
145        differently. PCRE now behaves in the same way as Perl, except in the case
146        of subroutine/recursion calls such as (?1) which have in any case always
147        been different (but PCRE had them first :-).
148    
149    16. Related to 15 above: Perl does not treat the | in a conditional group as
150        creating alternatives. Such a group is treated in the same way as an
151        ordinary group without any | characters when processing (*THEN). PCRE has
152        been changed to match Perl's behaviour.
153    
154    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
155        RunGrepTest script failed.
156    
157    18. Change 22 for version 13 caused atomic groups to use more stack. This is
158        inevitable for groups that contain captures, but it can lead to a lot of
159        stack use in large patterns. The old behaviour has been restored for atomic
160        groups that do not contain any capturing parentheses.
161    
162    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
163        suppress the check for a minimum subject length at run time. (If it was
164        given to pcre_exec() or pcre_dfa_exec() it did work.)
165    
166    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
167        fail to work when decoding hex characters in data strings in EBCDIC
168        environments.
169    
170    21. It appears that in at least one Mac OS environment, the isxdigit() function
171        is implemented as a macro that evaluates to its argument more than once,
172        contravening the C 90 Standard (I haven't checked a later standard). There
173        was an instance in pcretest which caused it to go wrong when processing
174        \x{...} escapes in subject strings. The has been rewritten to avoid using
175        things like p++ in the argument of isxdigit().
176    
177    
178    Version 8.13 16-Aug-2011
179    ------------------------
180    
181    1.  The Unicode data tables have been updated to Unicode 6.0.0.
182    
183    2.  Two minor typos in pcre_internal.h have been fixed.
184    
185    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
186        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
187        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
188    
189    4.  There were a number of related bugs in the code for matching backrefences
190        caselessly in UTF-8 mode when codes for the characters concerned were
191        different numbers of bytes. For example, U+023A and U+2C65 are an upper
192        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
193        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
194        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
195        2-byte code at the end of the subject (it thought there wasn't enough data
196        left).
197    
198    5.  Comprehensive information about what went wrong is now returned by
199        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
200        as the output vector has at least 2 elements. The offset of the start of
201        the failing character and a reason code are placed in the vector.
202    
203    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
204        now returned is for the first byte of the failing character, instead of the
205        last byte inspected. This is an incompatible change, but I hope it is small
206        enough not to be a problem. It makes the returned offset consistent with
207        pcre_exec() and pcre_dfa_exec().
208    
209    7.  pcretest now gives a text phrase as well as the error number when
210        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
211        failure, the offset and reason code are output.
212    
213    8.  When \R was used with a maximizing quantifier it failed to skip backwards
214        over a \r\n pair if the subsequent match failed. Instead, it just skipped
215        back over a single character (\n). This seems wrong (because it treated the
216        two characters as a single entity when going forwards), conflicts with the
217        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
218        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
219        has been changed.
220    
221    9.  Some internal refactoring has changed the processing so that the handling
222        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
223        time (the PCRE_DOTALL option was changed this way some time ago: version
224        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
225        which was always a bit of a fudge. It also means that there is one less
226        argument for the match() function, which reduces its stack requirements
227        slightly. This change also fixes an incompatibility with Perl: the pattern
228        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
229    
230    10. More internal refactoring has drastically reduced the number of recursive
231        calls to match() for possessively repeated groups such as (abc)++ when
232        using pcre_exec().
233    
234    11. While implementing 10, a number of bugs in the handling of groups were
235        discovered and fixed:
236    
237        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
238        (a|)*(?1) gave a compile-time internal error.
239        ((a|)+)+  did not notice that the outer group could match an empty string.
240        (^a|^)+   was not marked as anchored.
241        (.*a|.*)+ was not marked as matching at start or after a newline.
242    
243    12. Yet more internal refactoring has removed another argument from the match()
244        function. Special calls to this function are now indicated by setting a
245        value in a variable in the "match data" data block.
246    
247    13. Be more explicit in pcre_study() instead of relying on "default" for
248        opcodes that mean there is no starting character; this means that when new
249        ones are added and accidentally left out of pcre_study(), testing should
250        pick them up.
251    
252    14. The -s option of pcretest has been documented for ages as being an old
253        synonym of -m (show memory usage). I have changed it to mean "force study
254        for every regex", that is, assume /S for every regex. This is similar to -i
255        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
256        using it. It makes it easier to run collections of tests with and without
257        study enabled, and thereby test pcre_study() more easily. All the standard
258        tests are now run with and without -s (but some patterns can be marked as
259        "never study" - see 20 below).
260    
261    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
262        restoration of the capturing data to the outer values was not happening
263        correctly.
264    
265    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
266        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
267        pattern had matched an empty string, and so incorrectly returned a no
268        match.
269    
270    17. There was optimizing code for the last branch of non-capturing parentheses,
271        and also for the obeyed branch of a conditional subexpression, which used
272        tail recursion to cut down on stack usage. Unfortunately, now that there is
273        the possibility of (*THEN) occurring in these branches, tail recursion is
274        no longer possible because the return has to be checked for (*THEN). These
275        two optimizations have therefore been removed. [But see 8.20/11 above.]
276    
277    18. If a pattern containing \R was studied, it was assumed that \R always
278        matched two bytes, thus causing the minimum subject length to be
279        incorrectly computed because \R can also match just one byte.
280    
281    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
282        was incorrectly computed.
283    
284    20. If /S is present twice on a test pattern in pcretest input, it now
285        *disables* studying, thereby overriding the use of -s on the command line
286        (see 14 above). This is necessary for one or two tests to keep the output
287        identical in both cases.
288    
289    21. When (*ACCEPT) was used in an assertion that matched an empty string and
290        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
291    
292    22. When an atomic group that contained a capturing parenthesis was
293        successfully matched, but the branch in which it appeared failed, the
294        capturing was not being forgotten if a higher numbered group was later
295        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
296        group 1 to "a", when in fact it should be unset. This applied to multi-
297        branched capturing and non-capturing groups, repeated or not, and also to
298        positive assertions (capturing in negative assertions does not happen
299        in PCRE) and also to nested atomic groups.
300    
301    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
302        subject after a captured substring, to make it easier to tell which of a
303        number of identical substrings has been captured.
304    
305    24. The way atomic groups are processed by pcre_exec() has been changed so that
306        if they are repeated, backtracking one repetition now resets captured
307        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
308        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
309        "aaa". Previously, it would have been "a". As part of this code
310        refactoring, the way recursive calls are handled has also been changed.
311    
312    25. If an assertion condition captured any substrings, they were not passed
313        back unless some other capturing happened later. For example, if
314        (?(?=(a))a) was matched against "a", no capturing was returned.
315    
316    26. When studying a pattern that contained subroutine calls or assertions,
317        the code for finding the minimum length of a possible match was handling
318        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
319        group 1 called group 2 while simultaneously a separate group 2 called group
320        1). A stack overflow occurred in this case. I have fixed this by limiting
321        the recursion depth to 10.
322    
323    27. Updated RunTest.bat in the distribution to the version supplied by Tom
324        Fortmann. This supports explicit test numbers on the command line, and has
325        argument validation and error reporting.
326    
327    28. An instance of \X with an unlimited repeat could fail if at any point the
328        first character it looked at was a mark character.
329    
330    29. Some minor code refactoring concerning Unicode properties and scripts
331        should reduce the stack requirement of match() slightly.
332    
333    30. Added the '=' option to pcretest to check the setting of unused capturing
334        slots at the end of the pattern, which are documented as being -1, but are
335        not included in the return count.
336    
337    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
338        compiled something random. Now it gives a compile-time error (as does
339        Perl).
340    
341    32. A *MARK encountered during the processing of a positive assertion is now
342        recorded and passed back (compatible with Perl).
343    
344    33. If --only-matching or --colour was set on a pcregrep call whose pattern
345        had alternative anchored branches, the search for a second match in a line
346        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
347        matched the line "0102" twice. The same bug affected patterns that started
348        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
349        twice.
350    
351    34. Previously, PCRE did not allow quantification of assertions. However, Perl
352        does, and because of capturing effects, quantifying parenthesized
353        assertions may at times be useful. Quantifiers are now allowed for
354        parenthesized assertions.
355    
356    35. A minor code tidy in pcre_compile() when checking options for \R usage.
357    
358    36. \g was being checked for fancy things in a character class, when it should
359        just be a literal "g".
360    
361    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
362        appearance of a nested POSIX class supersedes an apparent external class.
363        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
364        unescaped square brackets may also appear as part of class names. For
365        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
366        more like Perl. (But see 8.20/1 above.)
367    
368    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
369        was because it thought it was \N{name}, which is not supported).
370    
371    39. Add minix to OS list not supporting the -S option in pcretest.
372    
373    40. PCRE tries to detect cases of infinite recursion at compile time, but it
374        cannot analyze patterns in sufficient detail to catch mutual recursions
375        such as ((?1))((?2)). There is now a runtime test that gives an error if a
376        subgroup is called recursively as a subpattern for a second time at the
377        same position in the subject string. In previous releases this might have
378        been caught by the recursion limit, or it might have run out of stack.
379    
380    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
381        happen only once. PCRE was, however incorrectly giving a compile time error
382        "recursive call could loop indefinitely" because it cannot analyze the
383        pattern in sufficient detail. The compile time test no longer happens when
384        PCRE is compiling a conditional subpattern, but actual runaway loops are
385        now caught at runtime (see 40 above).
386    
387    42. It seems that Perl allows any characters other than a closing parenthesis
388        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
389        has been changed to be the same.
390    
391    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
392        as not to get warnings when autogen.sh is called. Also changed
393        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
394    
395    44. To help people who use pcregrep to scan files containing exceedingly long
396        lines, the following changes have been made:
397    
398        (a) The default value of the buffer size parameter has been increased from
399            8K to 20K. (The actual buffer used is three times this size.)
400    
401        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
402            PCRE is built.
403    
404        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
405            to be set at run time.
406    
407        (d) Numerical values in pcregrep options can be followed by K or M, for
408            example --buffer-size=50K.
409    
410        (e) If a line being scanned overflows pcregrep's buffer, an error is now
411            given and the return code is set to 2.
412    
413    45. Add a pointer to the latest mark to the callout data block.
414    
415    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
416        partial match of an empty string instead of no match. This was specific to
417        the use of ".".
418    
419    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
420        complete match instead of a partial match. This bug was dependent on both
421        the PCRE_UTF8 and PCRE_DOTALL options being set.
422    
423    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
424        starting byte set, because \b was not being ignored.
425    
426    
427    Version 8.12 15-Jan-2011
428    ------------------------
429    
430    1.  Fixed some typos in the markup of the man pages, and wrote a script that
431        checks for such things as part of the documentation building process.
432    
433    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
434        --match-limit and --recursion-limit options (added for 8.11). In
435        particular, this made one of the standard tests fail. (The integer value
436        went into the wrong half of a long int.)
437    
438    3.  If the --colour option was given to pcregrep with -v (invert match), it
439        did strange things, either producing crazy output, or crashing. It should,
440        of course, ignore a request for colour when reporting lines that do not
441        match.
442    
443    4.  Another pcregrep bug caused similar problems if --colour was specified with
444        -M (multiline) and the pattern match finished with a line ending.
445    
446    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
447        matched in multiline mode, the following line was shown as part of the
448        match. This seems wrong, so I have changed it.
449    
450    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
451        the check for further matches in the same line (so they could be coloured)
452        to overrun the end of the current line. If another match was found, it was
453        incorrectly shown (and then shown again when found in the next line).
454    
455    7.  If pcregrep was compiled under Windows, there was a reference to the
456        function pcregrep_exit() before it was defined. I am assuming this was
457        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
458        reported by a user. I've moved the definition above the reference.
459    
460    
461    Version 8.11 10-Dec-2010
462  ------------------------  ------------------------
463    
464  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
465      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
466      backtracked to try for "b" instead of moving to the next alternative branch      backtracked to try for "b" instead of moving to the next alternative branch
467      at the same level (in this case, to look for "c"). The Perl documentation      at the same level (in this case, to look for "c"). The Perl documentation
468      is clear that when (*THEN) is backtracked onto, it goes to the "next      is clear that when (*THEN) is backtracked onto, it goes to the "next
469      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
470    
471  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
472      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
473      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
474      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
475      (*THEN).      (*THEN).
476    
477    3.  If \s appeared in a character class, it removed the VT character from
478        the class, even if it had been included by some previous item, for example
479        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
480        of \s, but is part of the POSIX "space" class.)
481    
482    4.  A partial match never returns an empty string (because you can always
483        match an empty string at the end of the subject); however the checking for
484        an empty string was starting at the "start of match" point. This has been
485        changed to the "earliest inspected character" point, because the returned
486        data for a partial match starts at this character. This means that, for
487        example, /(?<=abc)def/ gives a partial match for the subject "abc"
488        (previously it gave "no match").
489    
490    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
491        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
492        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
493        has an implication that the given string is incomplete (because a partial
494        match is preferred over a full match). For this reason, these items now
495        give a partial match in this situation. [Aside: previously, the one case
496        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
497        match rather than a full match, which was wrong by the old rules, but is
498        now correct.]
499    
500    6.  There was a bug in the handling of #-introduced comments, recognized when
501        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
502        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
503        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
504        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
505        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
506        places in pcre_compile().
507    
508    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
509        comments when looking ahead for named forward references to subpatterns,
510        the only newline sequence it recognized was NL. It now handles newlines
511        according to the set newline convention.
512    
513    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
514        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
515        cater for a lack of strerror(). These oversights have been fixed.
516    
517    9.  Added --match-limit and --recursion-limit to pcregrep.
518    
519    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
520    
521    11. When the -o option was used, pcregrep was setting a return code of 1, even
522        when matches were found, and --line-buffered was not being honoured.
523    
524    12. Added an optional parentheses number to the -o and --only-matching options
525        of pcregrep.
526    
527    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
528        can match an empty string. The code to do it in pcretest and pcredemo
529        needed fixing:
530    
531        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
532            only one byte after an empty string match just before CRLF (this case
533            just got forgotten; "any" and "anycrlf" were OK).
534    
535        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
536            mode when an empty string match preceded an ASCII character followed by
537            a non-ASCII character. (The code for advancing by one character rather
538            than one byte was nonsense.)
539    
540        (c) The pcredemo.c sample program did not have any code at all to handle
541            the cases when CRLF is a valid newline sequence.
542    
543    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
544        as a starting offset was within the subject string. There is now a new
545        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
546        negative or greater than the length of the string. In order to test this,
547        pcretest is extended to allow the setting of negative starting offsets.
548    
549    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
550        starting offset points to the beginning of a UTF-8 character was
551        unnecessarily clumsy. I tidied it up.
552    
553    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
554        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
555    
556    17. Nobody had reported that the --include_dir option, which was added in
557        release 7.7 should have been called --include-dir (hyphen, not underscore)
558        for compatibility with GNU grep. I have changed it to --include-dir, but
559        left --include_dir as an undocumented synonym, and the same for
560        --exclude-dir, though that is not available in GNU grep, at least as of
561        release 2.5.4.
562    
563    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
564        characters from a string of bytes) have been redefined so as not to use
565        loops, in order to improve performance in some environments. At the same
566        time, I abstracted some of the common code into auxiliary macros to save
567        repetition (this should not affect the compiled code).
568    
569    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
570        compile-time error is now given if \c is not followed by an ASCII
571        character, that is, a byte less than 128. (In EBCDIC mode, the code is
572        different, and any byte value is allowed.)
573    
574    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
575        START_OPTIMIZE option, which is now allowed at compile time - but just
576        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
577        to pcregrep and other applications that have no direct access to PCRE
578        options. The new /Y option in pcretest sets this option when calling
579        pcre_compile().
580    
581    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
582        back references. Groups containing recursive back references were forced to
583        be atomic by that change, but in the case of named groups, the amount of
584        memory required was incorrectly computed, leading to "Failed: internal
585        error: code overflow". This has been fixed.
586    
587    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
588        pcretest.c, to avoid build problems in some Borland environments.
589    
590    
591  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010

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