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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.0 02 Jul-08  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    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
63        incorrectly expecting the subject to contain another "a" after the start.
64    
65    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
66        in the match, the SKIP should be ignored. This was not happening; instead
67        the SKIP was being treated as NOMATCH. For patterns such as
68        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
69        tested.
70    
71    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
72        now much more compatible with Perl, in particular in cases where the result
73        is a non-match for a non-anchored pattern. For example, if
74        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
75        "m", where previously it did not return a name. A side effect of this
76        change is that for partial matches, the last encountered mark name is
77        returned, as for non matches. A number of tests that were previously not
78        Perl-compatible have been moved into the Perl-compatible test files. The
79        refactoring has had the pleasing side effect of removing one argument from
80        the match() function, thus reducing its stack requirements.
81    
82    
83    Version 8.20 21-Oct-2011
84    ------------------------
85    
86    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
87        a POSIX class. After further experiments with Perl, which convinced me that
88        Perl has bugs and confusions, a closing square bracket is no longer allowed
89        in a POSIX name. This bug also affected patterns with classes that started
90        with full stops.
91    
92    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
93        captured substring, but while checking the failing first alternative,
94        substring 1 is temporarily captured. If the output vector supplied to
95        pcre_exec() was not big enough for this capture, the yield of the function
96        was still zero ("insufficient space for captured substrings"). This cannot
97        be totally fixed without adding another stack variable, which seems a lot
98        of expense for a edge case. However, I have improved the situation in cases
99        such as /(a)(b)x|abc/ matched against "abc", where the return code
100        indicates that fewer than the maximum number of slots in the ovector have
101        been set.
102    
103    3.  Related to (2) above: when there are more back references in a pattern than
104        slots in the output vector, pcre_exec() uses temporary memory during
105        matching, and copies in the captures as far as possible afterwards. It was
106        using the entire output vector, but this conflicts with the specification
107        that only 2/3 is used for passing back captured substrings. Now it uses
108        only the first 2/3, for compatibility. This is, of course, another edge
109        case.
110    
111    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
112        main code base, and can be used by building with --enable-jit. When this is
113        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
114        runtime --no-jit option is given.
115    
116    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
117        ovector, the return from the function was zero, implying that there were
118        other matches that did not fit. The correct "exactly full" value is now
119        returned.
120    
121    6.  If a subpattern that was called recursively or as a subroutine contained
122        (*PRUNE) or any other control that caused it to give a non-standard return,
123        invalid errors such as "Error -26 (nested recursion at the same subject
124        position)" or even infinite loops could occur.
125    
126    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
127        computing the minimum length on reaching *ACCEPT, and so ended up with the
128        wrong value of 1 rather than 0. Further investigation indicates that
129        computing a minimum subject length in the presence of *ACCEPT is difficult
130        (think back references, subroutine calls), and so I have changed the code
131        so that no minimum is registered for a pattern that contains *ACCEPT.
132    
133    8.  If (*THEN) was present in the first (true) branch of a conditional group,
134        it was not handled as intended. [But see 16 below.]
135    
136    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
137        Sheri Pierce.
138    
139    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
140        the first byte in a match must be "a".
141    
142    11. Change 17 for 8.13 increased the recursion depth for patterns like
143        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
144        pattern contains any instances of (*THEN). If it does not, the old
145        optimizations are restored. It would be nice to do this on a per-group
146        basis, but at the moment that is not feasible.
147    
148    12. In some environments, the output of pcretest -C is CRLF terminated. This
149        broke RunTest's code that checks for the link size. A single white space
150        character after the value is now allowed for.
151    
152    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
153        For "fr", it uses the Windows-specific input and output files.
154    
155    14. If (*THEN) appeared in a group that was called recursively or as a
156        subroutine, it did not work as intended. [But see next item.]
157    
158    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
159        pattern fragments (but not containing any | characters). If A and B are
160        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
161        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
162        D. In other words, Perl considers parentheses that do not contain any |
163        characters to be part of a surrounding alternative, whereas PCRE was
164        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
165        differently. PCRE now behaves in the same way as Perl, except in the case
166        of subroutine/recursion calls such as (?1) which have in any case always
167        been different (but PCRE had them first :-).
168    
169    16. Related to 15 above: Perl does not treat the | in a conditional group as
170        creating alternatives. Such a group is treated in the same way as an
171        ordinary group without any | characters when processing (*THEN). PCRE has
172        been changed to match Perl's behaviour.
173    
174    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
175        RunGrepTest script failed.
176    
177    18. Change 22 for version 13 caused atomic groups to use more stack. This is
178        inevitable for groups that contain captures, but it can lead to a lot of
179        stack use in large patterns. The old behaviour has been restored for atomic
180        groups that do not contain any capturing parentheses.
181    
182    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
183        suppress the check for a minimum subject length at run time. (If it was
184        given to pcre_exec() or pcre_dfa_exec() it did work.)
185    
186    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
187        fail to work when decoding hex characters in data strings in EBCDIC
188        environments.
189    
190    21. It appears that in at least one Mac OS environment, the isxdigit() function
191        is implemented as a macro that evaluates to its argument more than once,
192        contravening the C 90 Standard (I haven't checked a later standard). There
193        was an instance in pcretest which caused it to go wrong when processing
194        \x{...} escapes in subject strings. The has been rewritten to avoid using
195        things like p++ in the argument of isxdigit().
196    
197    
198    Version 8.13 16-Aug-2011
199    ------------------------
200    
201    1.  The Unicode data tables have been updated to Unicode 6.0.0.
202    
203    2.  Two minor typos in pcre_internal.h have been fixed.
204    
205    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
206        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
207        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
208    
209    4.  There were a number of related bugs in the code for matching backrefences
210        caselessly in UTF-8 mode when codes for the characters concerned were
211        different numbers of bytes. For example, U+023A and U+2C65 are an upper
212        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
213        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
214        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
215        2-byte code at the end of the subject (it thought there wasn't enough data
216        left).
217    
218    5.  Comprehensive information about what went wrong is now returned by
219        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
220        as the output vector has at least 2 elements. The offset of the start of
221        the failing character and a reason code are placed in the vector.
222    
223    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
224        now returned is for the first byte of the failing character, instead of the
225        last byte inspected. This is an incompatible change, but I hope it is small
226        enough not to be a problem. It makes the returned offset consistent with
227        pcre_exec() and pcre_dfa_exec().
228    
229    7.  pcretest now gives a text phrase as well as the error number when
230        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
231        failure, the offset and reason code are output.
232    
233    8.  When \R was used with a maximizing quantifier it failed to skip backwards
234        over a \r\n pair if the subsequent match failed. Instead, it just skipped
235        back over a single character (\n). This seems wrong (because it treated the
236        two characters as a single entity when going forwards), conflicts with the
237        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
238        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
239        has been changed.
240    
241    9.  Some internal refactoring has changed the processing so that the handling
242        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
243        time (the PCRE_DOTALL option was changed this way some time ago: version
244        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
245        which was always a bit of a fudge. It also means that there is one less
246        argument for the match() function, which reduces its stack requirements
247        slightly. This change also fixes an incompatibility with Perl: the pattern
248        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
249    
250    10. More internal refactoring has drastically reduced the number of recursive
251        calls to match() for possessively repeated groups such as (abc)++ when
252        using pcre_exec().
253    
254    11. While implementing 10, a number of bugs in the handling of groups were
255        discovered and fixed:
256    
257        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
258        (a|)*(?1) gave a compile-time internal error.
259        ((a|)+)+  did not notice that the outer group could match an empty string.
260        (^a|^)+   was not marked as anchored.
261        (.*a|.*)+ was not marked as matching at start or after a newline.
262    
263    12. Yet more internal refactoring has removed another argument from the match()
264        function. Special calls to this function are now indicated by setting a
265        value in a variable in the "match data" data block.
266    
267    13. Be more explicit in pcre_study() instead of relying on "default" for
268        opcodes that mean there is no starting character; this means that when new
269        ones are added and accidentally left out of pcre_study(), testing should
270        pick them up.
271    
272    14. The -s option of pcretest has been documented for ages as being an old
273        synonym of -m (show memory usage). I have changed it to mean "force study
274        for every regex", that is, assume /S for every regex. This is similar to -i
275        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
276        using it. It makes it easier to run collections of tests with and without
277        study enabled, and thereby test pcre_study() more easily. All the standard
278        tests are now run with and without -s (but some patterns can be marked as
279        "never study" - see 20 below).
280    
281    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
282        restoration of the capturing data to the outer values was not happening
283        correctly.
284    
285    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
286        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
287        pattern had matched an empty string, and so incorrectly returned a no
288        match.
289    
290    17. There was optimizing code for the last branch of non-capturing parentheses,
291        and also for the obeyed branch of a conditional subexpression, which used
292        tail recursion to cut down on stack usage. Unfortunately, now that there is
293        the possibility of (*THEN) occurring in these branches, tail recursion is
294        no longer possible because the return has to be checked for (*THEN). These
295        two optimizations have therefore been removed. [But see 8.20/11 above.]
296    
297    18. If a pattern containing \R was studied, it was assumed that \R always
298        matched two bytes, thus causing the minimum subject length to be
299        incorrectly computed because \R can also match just one byte.
300    
301    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
302        was incorrectly computed.
303    
304    20. If /S is present twice on a test pattern in pcretest input, it now
305        *disables* studying, thereby overriding the use of -s on the command line
306        (see 14 above). This is necessary for one or two tests to keep the output
307        identical in both cases.
308    
309    21. When (*ACCEPT) was used in an assertion that matched an empty string and
310        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
311    
312    22. When an atomic group that contained a capturing parenthesis was
313        successfully matched, but the branch in which it appeared failed, the
314        capturing was not being forgotten if a higher numbered group was later
315        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
316        group 1 to "a", when in fact it should be unset. This applied to multi-
317        branched capturing and non-capturing groups, repeated or not, and also to
318        positive assertions (capturing in negative assertions does not happen
319        in PCRE) and also to nested atomic groups.
320    
321    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
322        subject after a captured substring, to make it easier to tell which of a
323        number of identical substrings has been captured.
324    
325    24. The way atomic groups are processed by pcre_exec() has been changed so that
326        if they are repeated, backtracking one repetition now resets captured
327        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
328        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
329        "aaa". Previously, it would have been "a". As part of this code
330        refactoring, the way recursive calls are handled has also been changed.
331    
332    25. If an assertion condition captured any substrings, they were not passed
333        back unless some other capturing happened later. For example, if
334        (?(?=(a))a) was matched against "a", no capturing was returned.
335    
336    26. When studying a pattern that contained subroutine calls or assertions,
337        the code for finding the minimum length of a possible match was handling
338        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
339        group 1 called group 2 while simultaneously a separate group 2 called group
340        1). A stack overflow occurred in this case. I have fixed this by limiting
341        the recursion depth to 10.
342    
343    27. Updated RunTest.bat in the distribution to the version supplied by Tom
344        Fortmann. This supports explicit test numbers on the command line, and has
345        argument validation and error reporting.
346    
347    28. An instance of \X with an unlimited repeat could fail if at any point the
348        first character it looked at was a mark character.
349    
350    29. Some minor code refactoring concerning Unicode properties and scripts
351        should reduce the stack requirement of match() slightly.
352    
353    30. Added the '=' option to pcretest to check the setting of unused capturing
354        slots at the end of the pattern, which are documented as being -1, but are
355        not included in the return count.
356    
357    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
358        compiled something random. Now it gives a compile-time error (as does
359        Perl).
360    
361    32. A *MARK encountered during the processing of a positive assertion is now
362        recorded and passed back (compatible with Perl).
363    
364    33. If --only-matching or --colour was set on a pcregrep call whose pattern
365        had alternative anchored branches, the search for a second match in a line
366        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
367        matched the line "0102" twice. The same bug affected patterns that started
368        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
369        twice.
370    
371    34. Previously, PCRE did not allow quantification of assertions. However, Perl
372        does, and because of capturing effects, quantifying parenthesized
373        assertions may at times be useful. Quantifiers are now allowed for
374        parenthesized assertions.
375    
376    35. A minor code tidy in pcre_compile() when checking options for \R usage.
377    
378    36. \g was being checked for fancy things in a character class, when it should
379        just be a literal "g".
380    
381    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
382        appearance of a nested POSIX class supersedes an apparent external class.
383        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
384        unescaped square brackets may also appear as part of class names. For
385        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
386        more like Perl. (But see 8.20/1 above.)
387    
388    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
389        was because it thought it was \N{name}, which is not supported).
390    
391    39. Add minix to OS list not supporting the -S option in pcretest.
392    
393    40. PCRE tries to detect cases of infinite recursion at compile time, but it
394        cannot analyze patterns in sufficient detail to catch mutual recursions
395        such as ((?1))((?2)). There is now a runtime test that gives an error if a
396        subgroup is called recursively as a subpattern for a second time at the
397        same position in the subject string. In previous releases this might have
398        been caught by the recursion limit, or it might have run out of stack.
399    
400    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
401        happen only once. PCRE was, however incorrectly giving a compile time error
402        "recursive call could loop indefinitely" because it cannot analyze the
403        pattern in sufficient detail. The compile time test no longer happens when
404        PCRE is compiling a conditional subpattern, but actual runaway loops are
405        now caught at runtime (see 40 above).
406    
407    42. It seems that Perl allows any characters other than a closing parenthesis
408        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
409        has been changed to be the same.
410    
411    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
412        as not to get warnings when autogen.sh is called. Also changed
413        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
414    
415    44. To help people who use pcregrep to scan files containing exceedingly long
416        lines, the following changes have been made:
417    
418        (a) The default value of the buffer size parameter has been increased from
419            8K to 20K. (The actual buffer used is three times this size.)
420    
421        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
422            PCRE is built.
423    
424        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
425            to be set at run time.
426    
427        (d) Numerical values in pcregrep options can be followed by K or M, for
428            example --buffer-size=50K.
429    
430        (e) If a line being scanned overflows pcregrep's buffer, an error is now
431            given and the return code is set to 2.
432    
433    45. Add a pointer to the latest mark to the callout data block.
434    
435    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
436        partial match of an empty string instead of no match. This was specific to
437        the use of ".".
438    
439    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
440        complete match instead of a partial match. This bug was dependent on both
441        the PCRE_UTF8 and PCRE_DOTALL options being set.
442    
443    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
444        starting byte set, because \b was not being ignored.
445    
446    
447    Version 8.12 15-Jan-2011
448    ------------------------
449    
450    1.  Fixed some typos in the markup of the man pages, and wrote a script that
451        checks for such things as part of the documentation building process.
452    
453    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
454        --match-limit and --recursion-limit options (added for 8.11). In
455        particular, this made one of the standard tests fail. (The integer value
456        went into the wrong half of a long int.)
457    
458    3.  If the --colour option was given to pcregrep with -v (invert match), it
459        did strange things, either producing crazy output, or crashing. It should,
460        of course, ignore a request for colour when reporting lines that do not
461        match.
462    
463    4.  Another pcregrep bug caused similar problems if --colour was specified with
464        -M (multiline) and the pattern match finished with a line ending.
465    
466    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
467        matched in multiline mode, the following line was shown as part of the
468        match. This seems wrong, so I have changed it.
469    
470    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
471        the check for further matches in the same line (so they could be coloured)
472        to overrun the end of the current line. If another match was found, it was
473        incorrectly shown (and then shown again when found in the next line).
474    
475    7.  If pcregrep was compiled under Windows, there was a reference to the
476        function pcregrep_exit() before it was defined. I am assuming this was
477        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
478        reported by a user. I've moved the definition above the reference.
479    
480    
481    Version 8.11 10-Dec-2010
482    ------------------------
483    
484    1.  (*THEN) was not working properly if there were untried alternatives prior
485        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
486        backtracked to try for "b" instead of moving to the next alternative branch
487        at the same level (in this case, to look for "c"). The Perl documentation
488        is clear that when (*THEN) is backtracked onto, it goes to the "next
489        alternative in the innermost enclosing group".
490    
491    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
492        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
493        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
494        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
495        (*THEN).
496    
497    3.  If \s appeared in a character class, it removed the VT character from
498        the class, even if it had been included by some previous item, for example
499        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
500        of \s, but is part of the POSIX "space" class.)
501    
502    4.  A partial match never returns an empty string (because you can always
503        match an empty string at the end of the subject); however the checking for
504        an empty string was starting at the "start of match" point. This has been
505        changed to the "earliest inspected character" point, because the returned
506        data for a partial match starts at this character. This means that, for
507        example, /(?<=abc)def/ gives a partial match for the subject "abc"
508        (previously it gave "no match").
509    
510    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
511        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
512        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
513        has an implication that the given string is incomplete (because a partial
514        match is preferred over a full match). For this reason, these items now
515        give a partial match in this situation. [Aside: previously, the one case
516        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
517        match rather than a full match, which was wrong by the old rules, but is
518        now correct.]
519    
520    6.  There was a bug in the handling of #-introduced comments, recognized when
521        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
522        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
523        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
524        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
525        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
526        places in pcre_compile().
527    
528    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
529        comments when looking ahead for named forward references to subpatterns,
530        the only newline sequence it recognized was NL. It now handles newlines
531        according to the set newline convention.
532    
533    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
534        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
535        cater for a lack of strerror(). These oversights have been fixed.
536    
537    9.  Added --match-limit and --recursion-limit to pcregrep.
538    
539    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
540    
541    11. When the -o option was used, pcregrep was setting a return code of 1, even
542        when matches were found, and --line-buffered was not being honoured.
543    
544    12. Added an optional parentheses number to the -o and --only-matching options
545        of pcregrep.
546    
547    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
548        can match an empty string. The code to do it in pcretest and pcredemo
549        needed fixing:
550    
551        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
552            only one byte after an empty string match just before CRLF (this case
553            just got forgotten; "any" and "anycrlf" were OK).
554    
555        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
556            mode when an empty string match preceded an ASCII character followed by
557            a non-ASCII character. (The code for advancing by one character rather
558            than one byte was nonsense.)
559    
560        (c) The pcredemo.c sample program did not have any code at all to handle
561            the cases when CRLF is a valid newline sequence.
562    
563    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
564        as a starting offset was within the subject string. There is now a new
565        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
566        negative or greater than the length of the string. In order to test this,
567        pcretest is extended to allow the setting of negative starting offsets.
568    
569    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
570        starting offset points to the beginning of a UTF-8 character was
571        unnecessarily clumsy. I tidied it up.
572    
573    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
574        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
575    
576    17. Nobody had reported that the --include_dir option, which was added in
577        release 7.7 should have been called --include-dir (hyphen, not underscore)
578        for compatibility with GNU grep. I have changed it to --include-dir, but
579        left --include_dir as an undocumented synonym, and the same for
580        --exclude-dir, though that is not available in GNU grep, at least as of
581        release 2.5.4.
582    
583    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
584        characters from a string of bytes) have been redefined so as not to use
585        loops, in order to improve performance in some environments. At the same
586        time, I abstracted some of the common code into auxiliary macros to save
587        repetition (this should not affect the compiled code).
588    
589    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
590        compile-time error is now given if \c is not followed by an ASCII
591        character, that is, a byte less than 128. (In EBCDIC mode, the code is
592        different, and any byte value is allowed.)
593    
594    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
595        START_OPTIMIZE option, which is now allowed at compile time - but just
596        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
597        to pcregrep and other applications that have no direct access to PCRE
598        options. The new /Y option in pcretest sets this option when calling
599        pcre_compile().
600    
601    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
602        back references. Groups containing recursive back references were forced to
603        be atomic by that change, but in the case of named groups, the amount of
604        memory required was incorrectly computed, leading to "Failed: internal
605        error: code overflow". This has been fixed.
606    
607    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
608        pcretest.c, to avoid build problems in some Borland environments.
609    
610    
611    Version 8.10 25-Jun-2010
612    ------------------------
613    
614    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
615        THEN.
616    
617    2.  (*ACCEPT) was not working when inside an atomic group.
618    
619    3.  Inside a character class, \B is treated as a literal by default, but
620        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
621        causes the error). The code is unchanged, but I tidied the documentation.
622    
623    4.  Inside a character class, PCRE always treated \R and \X as literals,
624        whereas Perl faults them if its -w option is set. I have changed PCRE so
625        that it faults them when PCRE_EXTRA is set.
626    
627    5.  Added support for \N, which always matches any character other than
628        newline. (It is the same as "." when PCRE_DOTALL is not set.)
629    
630    6.  When compiling pcregrep with newer versions of gcc which may have
631        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
632        declared with attribute warn_unused_result" were given. Just casting the
633        result to (void) does not stop the warnings; a more elaborate fudge is
634        needed. I've used a macro to implement this.
635    
636    7.  Minor change to pcretest.c to avoid a compiler warning.
637    
638    8.  Added four artifical Unicode properties to help with an option to make
639        \s etc use properties (see next item). The new properties are: Xan
640        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
641    
642    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
643        use Unicode properties. (*UCP) at the start of a pattern can be used to set
644        this option. Modified pcretest to add /W to test this facility. Added
645        REG_UCP to make it available via the POSIX interface.
646    
647    10. Added --line-buffered to pcregrep.
648    
649    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
650        studied, and the match started with a letter with a code point greater than
651        127 whose first byte was different to the first byte of the other case of
652        the letter, the other case of this starting letter was not recognized
653        (#976).
654    
655    12. If a pattern that was studied started with a repeated Unicode property
656        test, for example, \p{Nd}+, there was the theoretical possibility of
657        setting up an incorrect bitmap of starting bytes, but fortunately it could
658        not have actually happened in practice until change 8 above was made (it
659        added property types that matched character-matching opcodes).
660    
661    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
662        possible starting bytes for non-anchored patterns.
663    
664    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
665        \R, and also a number of cases that involve Unicode properties, both
666        explicit and implicit when PCRE_UCP is set.
667    
668    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
669        input, it could crash or give wrong results if characters with values
670        greater than 0xc0 were present in the subject string. (Detail: it assumed
671        UTF-8 input when processing these items.)
672    
673    16. Added a lot of (int) casts to avoid compiler warnings in systems where
674        size_t is 64-bit (#991).
675    
676    17. Added a check for running out of memory when PCRE is compiled with
677        --disable-stack-for-recursion (#990).
678    
679    18. If the last data line in a file for pcretest does not have a newline on
680        the end, a newline was missing in the output.
681    
682    19. The default pcre_chartables.c file recognizes only ASCII characters (values
683        less than 128) in its various bitmaps. However, there is a facility for
684        generating tables according to the current locale when PCRE is compiled. It
685        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
686        characters, are recognized by isspace() and therefore were getting set in
687        these tables, and indeed these tables seem to approximate to ISO 8859. This
688        caused a problem in UTF-8 mode when pcre_study() was used to create a list
689        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
690        which of course cannot start UTF-8 characters. I have changed the code so
691        that only real ASCII characters (less than 128) and the correct starting
692        bytes for UTF-8 encodings are set for characters greater than 127 when in
693        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
694        altogether.)
695    
696    20. Added the /T option to pcretest so as to be able to run tests with non-
697        standard character tables, thus making it possible to include the tests
698        used for 19 above in the standard set of tests.
699    
700    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
701        reference to a subpattern the other side of a comment that contains an
702        opening parenthesis caused either an internal compiling error, or a
703        reference to the wrong subpattern.
704    
705    
706    Version 8.02 19-Mar-2010
707    ------------------------
708    
709    1.  The Unicode data tables have been updated to Unicode 5.2.0.
710    
711    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
712        configured.
713    
714    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
715        original author of that file, following a query about its status.
716    
717    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
718        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
719    
720    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
721        quantifier applied to a forward-referencing subroutine call, could compile
722        incorrect code or give the error "internal error: previously-checked
723        referenced subpattern not found".
724    
725    6.  Both MS Visual Studio and Symbian OS have problems with initializing
726        variables to point to external functions. For these systems, therefore,
727        pcre_malloc etc. are now initialized to local functions that call the
728        relevant global functions.
729    
730    7.  There were two entries missing in the vectors called coptable and poptable
731        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
732        I've fixed the data, and added a kludgy way of testing at compile time that
733        the lengths are correct (equal to the number of opcodes).
734    
735    8.  Following on from 7, I added a similar kludge to check the length of the
736        eint vector in pcreposix.c.
737    
738    9.  Error texts for pcre_compile() are held as one long string to avoid too
739        much relocation at load time. To find a text, the string is searched,
740        counting zeros. There was no check for running off the end of the string,
741        which could happen if a new error number was added without updating the
742        string.
743    
744    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
745    
746    11. \K was not working if it appeared in an atomic group or in a group that
747        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
748        \K is "not well defined" if used in an assertion. PCRE now accepts it if
749        the assertion is positive, but not if it is negative.
750    
751    12. Change 11 fortuitously reduced the size of the stack frame used in the
752        "match()" function of pcre_exec.c by one pointer. Forthcoming
753        implementation of support for (*MARK) will need an extra pointer on the
754        stack; I have reserved it now, so that the stack frame size does not
755        decrease.
756    
757    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
758        item in branch that calls a recursion is a subroutine call - as in the
759        second branch in the above example - was incorrectly given the compile-
760        time error "recursive call could loop indefinitely" because pcre_compile()
761        was not correctly checking the subroutine for matching a non-empty string.
762    
763    14. The checks for overrunning compiling workspace could trigger after an
764        overrun had occurred. This is a "should never occur" error, but it can be
765        triggered by pathological patterns such as hundreds of nested parentheses.
766        The checks now trigger 100 bytes before the end of the workspace.
767    
768    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
769    
770    
771    Version 8.01 19-Jan-2010
772    ------------------------
773    
774    1.  If a pattern contained a conditional subpattern with only one branch (in
775        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
776        computed the wrong minimum data length (which is of course zero for such
777        subpatterns). This could cause incorrect "no match" results.
778    
779    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
780        the pattern is reset in the first branch, pcre_compile() failed with
781        "internal error: code overflow at offset...". This happened only when
782        the reset was to the original external option setting. (An optimization
783        abstracts leading options settings into an external setting, which was the
784        cause of this.)
785    
786    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
787        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
788        assertion pattern did not match (meaning that the assertion was true), it
789        was incorrectly treated as false if the SKIP had been reached during the
790        matching. This also applied to assertions used as conditions.
791    
792    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
793        assertion subpattern, including such a pattern used as a condition,
794        unpredictable results occurred, instead of the error return
795        PCRE_ERROR_DFA_UITEM.
796    
797    5.  The C++ GlobalReplace function was not working like Perl for the special
798        situation when an empty string is matched. It now does the fancy magic
799        stuff that is necessary.
800    
801    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
802        removed. (These were left over from very, very early versions of PCRE.)
803    
804    7.  Some cosmetic changes to the code to make life easier when compiling it
805        as part of something else:
806    
807        (a) Change DEBUG to PCRE_DEBUG.
808    
809        (b) In pcre_compile(), rename the member of the "branch_chain" structure
810            called "current" as "current_branch", to prevent a collision with the
811            Linux macro when compiled as a kernel module.
812    
813        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
814            prevent a collision with the Linux macro when compiled as a kernel
815            module.
816    
817    8.  In pcre_compile() there are some checks for integer overflows that used to
818        cast potentially large values to (double). This has been changed to that
819        when building, a check for int64_t is made, and if it is found, it is used
820        instead, thus avoiding the use of floating point arithmetic. (There is no
821        other use of FP in PCRE.) If int64_t is not found, the fallback is to
822        double.
823    
824    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
825        2005 (difference between two addresses compared to an unsigned value).
826    
827    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
828        custom one, because of the following reported problem in Windows:
829    
830          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
831              under Win32.
832          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
833              therefore missing the function definition.
834          - The compiler thus generates a "C" signature for the test function.
835          - The linker fails to find the "C" function.
836          - PCRE fails to configure if asked to do so against libbz2.
837    
838    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
839        messages were output:
840    
841          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
842          rerunning libtoolize, to keep the correct libtool macros in-tree.
843          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
844    
845        I have done both of these things.
846    
847    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
848        most of the time, it *can* run out if it is given a pattern that contains a
849        runaway infinite recursion. I updated the discussion in the pcrestack man
850        page.
851    
852    13. Now that we have gone to the x.xx style of version numbers, the minor
853        version may start with zero. Using 08 or 09 is a bad idea because users
854        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
855        interpreted as invalid octal numbers. I've updated the previous comment in
856        configure.ac, and also added a check that gives an error if 08 or 09 are
857        used.
858    
859    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
860        causing partial matching to fail when the end of the subject matched \W
861        in a UTF-8 pattern where \W was quantified with a minimum of 3.
862    
863    15. There were some discrepancies between the declarations in pcre_internal.h
864        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
865        their definitions. The declarations used "const uschar *" and the
866        definitions used USPTR. Even though USPTR is normally defined as "const
867        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
868        reported that: "This difference in casting confuses some C++ compilers, for
869        example, SunCC recognizes above declarations as different functions and
870        generates broken code for hbpcre." I have changed the declarations to use
871        USPTR.
872    
873    16. GNU libtool is named differently on some systems. The autogen.sh script now
874        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
875        (FreeBSD).
876    
877    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
878        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
879        comment: "Figure out how to create a longlong from a string: strtoll and
880        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
881        instance, but it only takes 2 args instead of 3!"
882    
883    18. A subtle bug concerned with back references has been fixed by a change of
884        specification, with a corresponding code fix. A pattern such as
885        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
886        refers, was giving matches when it shouldn't. For example, xa=xaaa would
887        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
888        same bug. Such groups have to be quantified to be useful, or contained
889        inside another quantified group. (If there's no repetition, the reference
890        can never match.) The problem arises because, having left the group and
891        moved on to the rest of the pattern, a later failure that backtracks into
892        the group uses the captured value from the final iteration of the group
893        rather than the correct earlier one. I have fixed this in PCRE by forcing
894        any group that contains a reference to itself to be an atomic group; that
895        is, there cannot be any backtracking into it once it has completed. This is
896        similar to recursive and subroutine calls.
897    
898    
899    Version 8.00 19-Oct-09
900    ----------------------
901    
902    1.  The table for translating pcre_compile() error codes into POSIX error codes
903        was out-of-date, and there was no check on the pcre_compile() error code
904        being within the table. This could lead to an OK return being given in
905        error.
906    
907    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
908        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
909        in a Windows environment.
910    
911    3.  The pcregrep --count option prints the count for each file even when it is
912        zero, as does GNU grep. However, pcregrep was also printing all files when
913        --files-with-matches was added. Now, when both options are given, it prints
914        counts only for those files that have at least one match. (GNU grep just
915        prints the file name in this circumstance, but including the count seems
916        more useful - otherwise, why use --count?) Also ensured that the
917        combination -clh just lists non-zero counts, with no names.
918    
919    4.  The long form of the pcregrep -F option was incorrectly implemented as
920        --fixed_strings instead of --fixed-strings. This is an incompatible change,
921        but it seems right to fix it, and I didn't think it was worth preserving
922        the old behaviour.
923    
924    5.  The command line items --regex=pattern and --regexp=pattern were not
925        recognized by pcregrep, which required --regex pattern or --regexp pattern
926        (with a space rather than an '='). The man page documented the '=' forms,
927        which are compatible with GNU grep; these now work.
928    
929    6.  No libpcreposix.pc file was created for pkg-config; there was just
930        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
931    
932    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
933        when UCP support is not needed, by modifying the Python script that
934        generates it from Unicode data files. This should not matter if the module
935        is correctly used as a library, but I received one complaint about 50K of
936        unwanted data. My guess is that the person linked everything into his
937        program rather than using a library. Anyway, it does no harm.
938    
939    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
940        was a minimum greater than 1 for a wide character in a possessive
941        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
942        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
943        character. Chaos in the form of incorrect output or a compiling loop could
944        result.
945    
946    9.  The restrictions on what a pattern can contain when partial matching is
947        requested for pcre_exec() have been removed. All patterns can now be
948        partially matched by this function. In addition, if there are at least two
949        slots in the offset vector, the offset of the earliest inspected character
950        for the match and the offset of the end of the subject are set in them when
951        PCRE_ERROR_PARTIAL is returned.
952    
953    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
954        synonymous with PCRE_PARTIAL, for backwards compatibility, and
955        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
956        and may be more useful for multi-segment matching.
957    
958    11. Partial matching with pcre_exec() is now more intuitive. A partial match
959        used to be given if ever the end of the subject was reached; now it is
960        given only if matching could not proceed because another character was
961        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
962        string "Z", which now yields "no match" instead of "partial match". In the
963        case of pcre_dfa_exec(), "no match" is given if every matching path for the
964        final character ended with (*FAIL).
965    
966    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
967        if the pattern had a "must contain" character that was already found in the
968        earlier partial match, unless partial matching was again requested. For
969        example, with the pattern /dog.(body)?/, the "must contain" character is
970        "g". If the first part-match was for the string "dog", restarting with
971        "sbody" failed. This bug has been fixed.
972    
973    13. The string returned by pcre_dfa_exec() after a partial match has been
974        changed so that it starts at the first inspected character rather than the
975        first character of the match. This makes a difference only if the pattern
976        starts with a lookbehind assertion or \b or \B (\K is not supported by
977        pcre_dfa_exec()). It's an incompatible change, but it makes the two
978        matching functions compatible, and I think it's the right thing to do.
979    
980    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
981        so that the demonstration program is easily available in environments where
982        PCRE has not been installed from source.
983    
984    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
985        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
986        library.
987    
988    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
989        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
990        is not the first non-POSIX option to be added. Clearly some people find
991        these options useful.
992    
993    17. If a caller to the POSIX matching function regexec() passes a non-zero
994        value for nmatch with a NULL value for pmatch, the value of
995        nmatch is forced to zero.
996    
997    18. RunGrepTest did not have a test for the availability of the -u option of
998        the diff command, as RunTest does. It now checks in the same way as
999        RunTest, and also checks for the -b option.
1000    
1001    19. If an odd number of negated classes containing just a single character
1002        interposed, within parentheses, between a forward reference to a named
1003        subpattern and the definition of the subpattern, compilation crashed with
1004        an internal error, complaining that it could not find the referenced
1005        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1006        [The bug was that it was starting one character too far in when skipping
1007        over the character class, thus treating the ] as data rather than
1008        terminating the class. This meant it could skip too much.]
1009    
1010    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1011        /g option in pcretest when the pattern contains \K, which makes it possible
1012        to have an empty string match not at the start, even when the pattern is
1013        anchored. Updated pcretest and pcredemo to use this option.
1014    
1015    21. If the maximum number of capturing subpatterns in a recursion was greater
1016        than the maximum at the outer level, the higher number was returned, but
1017        with unset values at the outer level. The correct (outer level) value is
1018        now given.
1019    
1020    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1021        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1022        make it do so. The string so far is captured, making this feature
1023        compatible with Perl.
1024    
1025    23. The tests have been re-organized, adding tests 11 and 12, to make it
1026        possible to check the Perl 5.10 features against Perl 5.10.
1027    
1028    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1029        pattern matches a fixed length string. PCRE did not allow this; now it
1030        does. Neither allows recursion.
1031    
1032    25. I finally figured out how to implement a request to provide the minimum
1033        length of subject string that was needed in order to match a given pattern.
1034        (It was back references and recursion that I had previously got hung up
1035        on.) This code has now been added to pcre_study(); it finds a lower bound
1036        to the length of subject needed. It is not necessarily the greatest lower
1037        bound, but using it to avoid searching strings that are too short does give
1038        some useful speed-ups. The value is available to calling programs via
1039        pcre_fullinfo().
1040    
1041    26. While implementing 25, I discovered to my embarrassment that pcretest had
1042        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1043        study optimizations had never been tested with that matching function.
1044        Oops. What is worse, even when it was passed study data, there was a bug in
1045        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1046        were also very few tests of studied patterns with pcre_dfa_exec().
1047    
1048    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1049        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1050        on the other side of the coin, they are no longer allowed to have different
1051        names, because these cannot be distinguished in PCRE, and this has caused
1052        confusion. (This is a difference from Perl.)
1053    
1054    28. When duplicate subpattern names are present (necessarily with different
1055        numbers, as required by 27 above), and a test is made by name in a
1056        conditional pattern, either for a subpattern having been matched, or for
1057        recursion in such a pattern, all the associated numbered subpatterns are
1058        tested, and the overall condition is true if the condition is true for any
1059        one of them. This is the way Perl works, and is also more like the way
1060        testing by number works.
1061    
1062    
1063    Version 7.9 11-Apr-09
1064    ---------------------
1065    
1066    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1067        (pcretest), all targets were linked against these libraries. This included
1068        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1069        libraries. This caused unwanted dependencies to be created. This problem
1070        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1071        pcretest is linked with readline.
1072    
1073    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1074        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1075        moved outside it again, because FALSE and TRUE are already defined in AIX,
1076        but BOOL is not.
1077    
1078    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1079        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1080    
1081    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1082        hyphens) following file names and line numbers when outputting matching
1083        lines. This is not true; no spaces are inserted. I have also clarified the
1084        wording for the --colour (or --color) option.
1085    
1086    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1087        was not coloured; this is different to GNU grep, so I have changed it to be
1088        the same.
1089    
1090    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1091        each matching line was coloured. Now it goes on to look for further matches
1092        of any of the test patterns, which is the same behaviour as GNU grep.
1093    
1094    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1095        doesn't make sense to accept an empty string match in pcregrep, so I have
1096        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1097        seems to be how GNU grep behaves.
1098    
1099    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1100        start or after a newline", because the conditional assertion was not being
1101        correctly handled. The rule now is that both the assertion and what follows
1102        in the first alternative must satisfy the test.
1103    
1104    9.  If auto-callout was enabled in a pattern with a conditional group whose
1105        condition was an assertion, PCRE could crash during matching, both with
1106        pcre_exec() and pcre_dfa_exec().
1107    
1108    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1109        used for matching.
1110    
1111    11. Unicode property support in character classes was not working for
1112        characters (bytes) greater than 127 when not in UTF-8 mode.
1113    
1114    12. Added the -M command line option to pcretest.
1115    
1116    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1117    
1118    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1119    
1120    16. Added comments and documentation about mis-use of no_arg in the C++
1121        wrapper.
1122    
1123    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1124        from Martin Jerabek that uses macro names for all relevant character and
1125        string constants.
1126    
1127    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1128        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1129        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1130        these, but not everybody uses configure.
1131    
1132    19. A conditional group that had only one branch was not being correctly
1133        recognized as an item that could match an empty string. This meant that an
1134        enclosing group might also not be so recognized, causing infinite looping
1135        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1136        with the subject "ab", where knowledge that the repeated group can match
1137        nothing is needed in order to break the loop.
1138    
1139    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1140        exec(), but without supplying a callout function, matching went wrong.
1141    
1142    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1143        leak if the size of the offset vector was greater than 30. When the vector
1144        is smaller, the saved offsets during recursion go onto a local stack
1145        vector, but for larger vectors malloc() is used. It was failing to free
1146        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1147        error, in fact).
1148    
1149    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1150        heapframe that is used only when UTF-8 support is enabled. This caused no
1151        problem, but was untidy.
1152    
1153    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1154        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1155        included within another project.
1156    
1157    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1158        slightly modified by me:
1159    
1160          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1161              not building pcregrep.
1162    
1163          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1164              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1165    
1166    25. Forward references, both numeric and by name, in patterns that made use of
1167        duplicate group numbers, could behave incorrectly or give incorrect errors,
1168        because when scanning forward to find the reference group, PCRE was not
1169        taking into account the duplicate group numbers. A pattern such as
1170        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1171    
1172    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1173        the feature of a custom pointer more persuasive (as requested by a user).
1174    
1175    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1176        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1177        pre-defined.
1178    
1179    28. Added support for (*UTF8) at the start of a pattern.
1180    
1181    29. Arrange for flags added by the "release type" setting in CMake to be shown
1182        in the configuration summary.
1183    
1184    
1185    Version 7.8 05-Sep-08
1186  ---------------------  ---------------------
1187    
1188  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 13  Version 8.0 02 Jul-08 Line 1194  Version 8.0 02 Jul-08
1194    
1195  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1196      scripts.      scripts.
1197    
1198  3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained  3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1199      a group with a zero qualifier. The result of the study could be incorrect,      a group with a zero qualifier. The result of the study could be incorrect,
1200      or the function might crash, depending on the pattern.      or the function might crash, depending on the pattern.
1201    
1202  4.  Caseless matching was not working for non-ASCII characters in back  4.  Caseless matching was not working for non-ASCII characters in back
1203      references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.      references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1204      It now works when Unicode Property Support is available.      It now works when Unicode Property Support is available.
1205    
1206  5.  In pcretest, an escape such as \x{de} in the data was always generating  5.  In pcretest, an escape such as \x{de} in the data was always generating
1207      a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in      a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1208      non-UTF-8 mode. If the value is greater than 255, it gives a warning about      non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1209      truncation.      truncation.
1210    
1211  6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).  6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1212    
1213  7.  Added two (int) casts to pcregrep when printing the difference of two  7.  Added two (int) casts to pcregrep when printing the difference of two
1214      pointers, in case they are 64-bit values.      pointers, in case they are 64-bit values.
1215    
1216    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1217        test 2 if it fails.
1218    
1219    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1220        and a #define of that name to empty if it is not externally set. This is to
1221        allow users of MSVC to set it if necessary.
1222    
1223    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1224        the convenience functions in the pcre_get.c source file.
1225    
1226    11. An option change at the start of a pattern that had top-level alternatives
1227        could cause overwriting and/or a crash. This command provoked a crash in
1228        some environments:
1229    
1230          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1231    
1232        This potential security problem was recorded as CVE-2008-2371.
1233    
1234    12. For a pattern where the match had to start at the beginning or immediately
1235        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1236        pcre_dfa_exec() could read past the end of the passed subject if there was
1237        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1238        pcretest so that it places the subject at the end of its malloc-ed buffer.
1239    
1240    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1241        exec() might read past the end of the data buffer in UTF-8 mode.
1242    
1243    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1244        the data contained the byte 0x85 as part of a UTF-8 character within its
1245        first line. This applied both to normal and DFA matching.
1246    
1247    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1248        /^[^d]*?$/8 failed to match "abc".
1249    
1250    16. Added a missing copyright notice to pcrecpp_internal.h.
1251    
1252    17. Make it more clear in the documentation that values returned from
1253        pcre_exec() in ovector are byte offsets, not character counts.
1254    
1255    18. Tidied a few places to stop certain compilers from issuing warnings.
1256    
1257    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1258        supplied by Stefan Weber. I made a further small update for 7.8 because
1259        there is a change of source arrangements: the pcre_searchfuncs.c module is
1260        replaced by pcre_ucd.c.
1261    
1262    
1263  Version 7.7 07-May-08  Version 7.7 07-May-08
1264  ---------------------  ---------------------

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