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

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