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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  Version 8.30
5    ------------
6    
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
9    
10    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
11        only in quite long subpatterns.
12    
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
15    
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
20    
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
25    
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
28    
29    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
30        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
31        from a file.
32    
33    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
34        rounding is not applied in this particular case).
35    
36    
37    Version 8.21 12-Dec-2011
38    ------------------------
39    
40    1.  Updating the JIT compiler.
41    
42    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
43        are added as well.
44    
45    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
46        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
47        calling _pcre_jit_exec. Some extra comments are added.
48    
49    4.  (*MARK) settings inside atomic groups that do not contain any capturing
50        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
51        was introduced by change 18 for 8.20.
52    
53    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
54        ECMA-262 standard.
55    
56    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
57        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
58        This bug was probably introduced by change 9 of 8.13.
59    
60    7.  While fixing 6 above, I noticed that a number of other items were being
61        incorrectly rejected as "not fixed length". This arose partly because newer
62        opcodes had not been added to the fixed-length checking code. I have (a)
63        corrected the bug and added tests for these items, and (b) arranged for an
64        error to occur if an unknown opcode is encountered while checking for fixed
65        length instead of just assuming "not fixed length". The items that were
66        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
67        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
68        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
69    
70    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
71        being incorrectly compiled and would have given unpredicatble results.
72    
73    9.  A possessively repeated subpattern with minimum repeat count greater than
74        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
75        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
76        the first (A) could occur when it should not.
77    
78    10. Add a cast and remove a redundant test from the code.
79    
80    11. JIT should use pcre_malloc/pcre_free for allocation.
81    
82    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
83        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
84        is anything other than /usr, -L is still shown).
85    
86    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
87    
88    14. Perl does not support \N without a following name in a [] class; PCRE now
89        also gives an error.
90    
91    15. If a forward reference was repeated with an upper limit of around 2000,
92        it caused the error "internal error: overran compiling workspace". The
93        maximum number of forward references (including repeats) was limited by the
94        internal workspace, and dependent on the LINK_SIZE. The code has been
95        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
96        the default depends on LINK_SIZE. There is a new upper limit (for safety)
97        of around 200,000 forward references. While doing this, I also speeded up
98        the filling in of repeated forward references.
99    
100    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
101        incorrectly expecting the subject to contain another "a" after the start.
102    
103    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
104        in the match, the SKIP should be ignored. This was not happening; instead
105        the SKIP was being treated as NOMATCH. For patterns such as
106        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
107        tested.
108    
109    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
110        now much more compatible with Perl, in particular in cases where the result
111        is a non-match for a non-anchored pattern. For example, if
112        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
113        "m", where previously it did not return a name. A side effect of this
114        change is that for partial matches, the last encountered mark name is
115        returned, as for non matches. A number of tests that were previously not
116        Perl-compatible have been moved into the Perl-compatible test files. The
117        refactoring has had the pleasing side effect of removing one argument from
118        the match() function, thus reducing its stack requirements.
119    
120    19. If the /S+ option was used in pcretest to study a pattern using JIT,
121        subsequent uses of /S (without +) incorrectly behaved like /S+.
122    
123    21. Retrieve executable code size support for the JIT compiler and fixing
124        some warnings.
125    
126    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
127        not work when the shorter character appeared right at the end of the
128        subject string.
129    
130    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
131        systems.
132    
133    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
134        output it when the /M option is used in pcretest.
135    
136    25. The CheckMan script was not being included in the distribution. Also, added
137        an explicit "perl" to run Perl scripts from the PrepareRelease script
138        because this is reportedly needed in Windows.
139    
140    26. If study data was being save in a file and studying had not found a set of
141        "starts with" bytes for the pattern, the data written to the file (though
142        never used) was taken from uninitialized memory and so caused valgrind to
143        complain.
144    
145    27. Updated RunTest.bat as provided by Sheri Pierce.
146    
147    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
148    
149    29. Computation of memory usage for the table of capturing group names was
150        giving an unnecessarily large value.
151    
152    
153    Version 8.20 21-Oct-2011
154    ------------------------
155    
156    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
157        a POSIX class. After further experiments with Perl, which convinced me that
158        Perl has bugs and confusions, a closing square bracket is no longer allowed
159        in a POSIX name. This bug also affected patterns with classes that started
160        with full stops.
161    
162    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
163        captured substring, but while checking the failing first alternative,
164        substring 1 is temporarily captured. If the output vector supplied to
165        pcre_exec() was not big enough for this capture, the yield of the function
166        was still zero ("insufficient space for captured substrings"). This cannot
167        be totally fixed without adding another stack variable, which seems a lot
168        of expense for a edge case. However, I have improved the situation in cases
169        such as /(a)(b)x|abc/ matched against "abc", where the return code
170        indicates that fewer than the maximum number of slots in the ovector have
171        been set.
172    
173    3.  Related to (2) above: when there are more back references in a pattern than
174        slots in the output vector, pcre_exec() uses temporary memory during
175        matching, and copies in the captures as far as possible afterwards. It was
176        using the entire output vector, but this conflicts with the specification
177        that only 2/3 is used for passing back captured substrings. Now it uses
178        only the first 2/3, for compatibility. This is, of course, another edge
179        case.
180    
181    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
182        main code base, and can be used by building with --enable-jit. When this is
183        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
184        runtime --no-jit option is given.
185    
186    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
187        ovector, the return from the function was zero, implying that there were
188        other matches that did not fit. The correct "exactly full" value is now
189        returned.
190    
191    6.  If a subpattern that was called recursively or as a subroutine contained
192        (*PRUNE) or any other control that caused it to give a non-standard return,
193        invalid errors such as "Error -26 (nested recursion at the same subject
194        position)" or even infinite loops could occur.
195    
196    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
197        computing the minimum length on reaching *ACCEPT, and so ended up with the
198        wrong value of 1 rather than 0. Further investigation indicates that
199        computing a minimum subject length in the presence of *ACCEPT is difficult
200        (think back references, subroutine calls), and so I have changed the code
201        so that no minimum is registered for a pattern that contains *ACCEPT.
202    
203    8.  If (*THEN) was present in the first (true) branch of a conditional group,
204        it was not handled as intended. [But see 16 below.]
205    
206    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
207        Sheri Pierce.
208    
209    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
210        the first byte in a match must be "a".
211    
212    11. Change 17 for 8.13 increased the recursion depth for patterns like
213        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
214        pattern contains any instances of (*THEN). If it does not, the old
215        optimizations are restored. It would be nice to do this on a per-group
216        basis, but at the moment that is not feasible.
217    
218    12. In some environments, the output of pcretest -C is CRLF terminated. This
219        broke RunTest's code that checks for the link size. A single white space
220        character after the value is now allowed for.
221    
222    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
223        For "fr", it uses the Windows-specific input and output files.
224    
225    14. If (*THEN) appeared in a group that was called recursively or as a
226        subroutine, it did not work as intended. [But see next item.]
227    
228    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
229        pattern fragments (but not containing any | characters). If A and B are
230        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
231        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
232        D. In other words, Perl considers parentheses that do not contain any |
233        characters to be part of a surrounding alternative, whereas PCRE was
234        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
235        differently. PCRE now behaves in the same way as Perl, except in the case
236        of subroutine/recursion calls such as (?1) which have in any case always
237        been different (but PCRE had them first :-).
238    
239    16. Related to 15 above: Perl does not treat the | in a conditional group as
240        creating alternatives. Such a group is treated in the same way as an
241        ordinary group without any | characters when processing (*THEN). PCRE has
242        been changed to match Perl's behaviour.
243    
244    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
245        RunGrepTest script failed.
246    
247    18. Change 22 for version 13 caused atomic groups to use more stack. This is
248        inevitable for groups that contain captures, but it can lead to a lot of
249        stack use in large patterns. The old behaviour has been restored for atomic
250        groups that do not contain any capturing parentheses.
251    
252    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
253        suppress the check for a minimum subject length at run time. (If it was
254        given to pcre_exec() or pcre_dfa_exec() it did work.)
255    
256    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
257        fail to work when decoding hex characters in data strings in EBCDIC
258        environments.
259    
260    21. It appears that in at least one Mac OS environment, the isxdigit() function
261        is implemented as a macro that evaluates to its argument more than once,
262        contravening the C 90 Standard (I haven't checked a later standard). There
263        was an instance in pcretest which caused it to go wrong when processing
264        \x{...} escapes in subject strings. The has been rewritten to avoid using
265        things like p++ in the argument of isxdigit().
266    
267    
268    Version 8.13 16-Aug-2011
269    ------------------------
270    
271    1.  The Unicode data tables have been updated to Unicode 6.0.0.
272    
273    2.  Two minor typos in pcre_internal.h have been fixed.
274    
275    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
276        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
277        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
278    
279    4.  There were a number of related bugs in the code for matching backrefences
280        caselessly in UTF-8 mode when codes for the characters concerned were
281        different numbers of bytes. For example, U+023A and U+2C65 are an upper
282        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
283        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
284        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
285        2-byte code at the end of the subject (it thought there wasn't enough data
286        left).
287    
288    5.  Comprehensive information about what went wrong is now returned by
289        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
290        as the output vector has at least 2 elements. The offset of the start of
291        the failing character and a reason code are placed in the vector.
292    
293    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
294        now returned is for the first byte of the failing character, instead of the
295        last byte inspected. This is an incompatible change, but I hope it is small
296        enough not to be a problem. It makes the returned offset consistent with
297        pcre_exec() and pcre_dfa_exec().
298    
299    7.  pcretest now gives a text phrase as well as the error number when
300        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
301        failure, the offset and reason code are output.
302    
303    8.  When \R was used with a maximizing quantifier it failed to skip backwards
304        over a \r\n pair if the subsequent match failed. Instead, it just skipped
305        back over a single character (\n). This seems wrong (because it treated the
306        two characters as a single entity when going forwards), conflicts with the
307        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
308        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
309        has been changed.
310    
311    9.  Some internal refactoring has changed the processing so that the handling
312        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
313        time (the PCRE_DOTALL option was changed this way some time ago: version
314        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
315        which was always a bit of a fudge. It also means that there is one less
316        argument for the match() function, which reduces its stack requirements
317        slightly. This change also fixes an incompatibility with Perl: the pattern
318        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
319    
320    10. More internal refactoring has drastically reduced the number of recursive
321        calls to match() for possessively repeated groups such as (abc)++ when
322        using pcre_exec().
323    
324    11. While implementing 10, a number of bugs in the handling of groups were
325        discovered and fixed:
326    
327        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
328        (a|)*(?1) gave a compile-time internal error.
329        ((a|)+)+  did not notice that the outer group could match an empty string.
330        (^a|^)+   was not marked as anchored.
331        (.*a|.*)+ was not marked as matching at start or after a newline.
332    
333    12. Yet more internal refactoring has removed another argument from the match()
334        function. Special calls to this function are now indicated by setting a
335        value in a variable in the "match data" data block.
336    
337    13. Be more explicit in pcre_study() instead of relying on "default" for
338        opcodes that mean there is no starting character; this means that when new
339        ones are added and accidentally left out of pcre_study(), testing should
340        pick them up.
341    
342    14. The -s option of pcretest has been documented for ages as being an old
343        synonym of -m (show memory usage). I have changed it to mean "force study
344        for every regex", that is, assume /S for every regex. This is similar to -i
345        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
346        using it. It makes it easier to run collections of tests with and without
347        study enabled, and thereby test pcre_study() more easily. All the standard
348        tests are now run with and without -s (but some patterns can be marked as
349        "never study" - see 20 below).
350    
351    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
352        restoration of the capturing data to the outer values was not happening
353        correctly.
354    
355    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
356        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
357        pattern had matched an empty string, and so incorrectly returned a no
358        match.
359    
360    17. There was optimizing code for the last branch of non-capturing parentheses,
361        and also for the obeyed branch of a conditional subexpression, which used
362        tail recursion to cut down on stack usage. Unfortunately, now that there is
363        the possibility of (*THEN) occurring in these branches, tail recursion is
364        no longer possible because the return has to be checked for (*THEN). These
365        two optimizations have therefore been removed. [But see 8.20/11 above.]
366    
367    18. If a pattern containing \R was studied, it was assumed that \R always
368        matched two bytes, thus causing the minimum subject length to be
369        incorrectly computed because \R can also match just one byte.
370    
371    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
372        was incorrectly computed.
373    
374    20. If /S is present twice on a test pattern in pcretest input, it now
375        *disables* studying, thereby overriding the use of -s on the command line
376        (see 14 above). This is necessary for one or two tests to keep the output
377        identical in both cases.
378    
379    21. When (*ACCEPT) was used in an assertion that matched an empty string and
380        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
381    
382    22. When an atomic group that contained a capturing parenthesis was
383        successfully matched, but the branch in which it appeared failed, the
384        capturing was not being forgotten if a higher numbered group was later
385        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
386        group 1 to "a", when in fact it should be unset. This applied to multi-
387        branched capturing and non-capturing groups, repeated or not, and also to
388        positive assertions (capturing in negative assertions does not happen
389        in PCRE) and also to nested atomic groups.
390    
391    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
392        subject after a captured substring, to make it easier to tell which of a
393        number of identical substrings has been captured.
394    
395    24. The way atomic groups are processed by pcre_exec() has been changed so that
396        if they are repeated, backtracking one repetition now resets captured
397        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
398        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
399        "aaa". Previously, it would have been "a". As part of this code
400        refactoring, the way recursive calls are handled has also been changed.
401    
402    25. If an assertion condition captured any substrings, they were not passed
403        back unless some other capturing happened later. For example, if
404        (?(?=(a))a) was matched against "a", no capturing was returned.
405    
406    26. When studying a pattern that contained subroutine calls or assertions,
407        the code for finding the minimum length of a possible match was handling
408        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
409        group 1 called group 2 while simultaneously a separate group 2 called group
410        1). A stack overflow occurred in this case. I have fixed this by limiting
411        the recursion depth to 10.
412    
413    27. Updated RunTest.bat in the distribution to the version supplied by Tom
414        Fortmann. This supports explicit test numbers on the command line, and has
415        argument validation and error reporting.
416    
417    28. An instance of \X with an unlimited repeat could fail if at any point the
418        first character it looked at was a mark character.
419    
420    29. Some minor code refactoring concerning Unicode properties and scripts
421        should reduce the stack requirement of match() slightly.
422    
423    30. Added the '=' option to pcretest to check the setting of unused capturing
424        slots at the end of the pattern, which are documented as being -1, but are
425        not included in the return count.
426    
427    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
428        compiled something random. Now it gives a compile-time error (as does
429        Perl).
430    
431    32. A *MARK encountered during the processing of a positive assertion is now
432        recorded and passed back (compatible with Perl).
433    
434    33. If --only-matching or --colour was set on a pcregrep call whose pattern
435        had alternative anchored branches, the search for a second match in a line
436        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
437        matched the line "0102" twice. The same bug affected patterns that started
438        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
439        twice.
440    
441    34. Previously, PCRE did not allow quantification of assertions. However, Perl
442        does, and because of capturing effects, quantifying parenthesized
443        assertions may at times be useful. Quantifiers are now allowed for
444        parenthesized assertions.
445    
446    35. A minor code tidy in pcre_compile() when checking options for \R usage.
447    
448    36. \g was being checked for fancy things in a character class, when it should
449        just be a literal "g".
450    
451    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
452        appearance of a nested POSIX class supersedes an apparent external class.
453        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
454        unescaped square brackets may also appear as part of class names. For
455        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
456        more like Perl. (But see 8.20/1 above.)
457    
458    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
459        was because it thought it was \N{name}, which is not supported).
460    
461    39. Add minix to OS list not supporting the -S option in pcretest.
462    
463    40. PCRE tries to detect cases of infinite recursion at compile time, but it
464        cannot analyze patterns in sufficient detail to catch mutual recursions
465        such as ((?1))((?2)). There is now a runtime test that gives an error if a
466        subgroup is called recursively as a subpattern for a second time at the
467        same position in the subject string. In previous releases this might have
468        been caught by the recursion limit, or it might have run out of stack.
469    
470    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
471        happen only once. PCRE was, however incorrectly giving a compile time error
472        "recursive call could loop indefinitely" because it cannot analyze the
473        pattern in sufficient detail. The compile time test no longer happens when
474        PCRE is compiling a conditional subpattern, but actual runaway loops are
475        now caught at runtime (see 40 above).
476    
477    42. It seems that Perl allows any characters other than a closing parenthesis
478        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
479        has been changed to be the same.
480    
481    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
482        as not to get warnings when autogen.sh is called. Also changed
483        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
484    
485    44. To help people who use pcregrep to scan files containing exceedingly long
486        lines, the following changes have been made:
487    
488        (a) The default value of the buffer size parameter has been increased from
489            8K to 20K. (The actual buffer used is three times this size.)
490    
491        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
492            PCRE is built.
493    
494        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
495            to be set at run time.
496    
497        (d) Numerical values in pcregrep options can be followed by K or M, for
498            example --buffer-size=50K.
499    
500        (e) If a line being scanned overflows pcregrep's buffer, an error is now
501            given and the return code is set to 2.
502    
503    45. Add a pointer to the latest mark to the callout data block.
504    
505    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
506        partial match of an empty string instead of no match. This was specific to
507        the use of ".".
508    
509    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
510        complete match instead of a partial match. This bug was dependent on both
511        the PCRE_UTF8 and PCRE_DOTALL options being set.
512    
513    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
514        starting byte set, because \b was not being ignored.
515    
516    
517    Version 8.12 15-Jan-2011
518    ------------------------
519    
520    1.  Fixed some typos in the markup of the man pages, and wrote a script that
521        checks for such things as part of the documentation building process.
522    
523    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
524        --match-limit and --recursion-limit options (added for 8.11). In
525        particular, this made one of the standard tests fail. (The integer value
526        went into the wrong half of a long int.)
527    
528    3.  If the --colour option was given to pcregrep with -v (invert match), it
529        did strange things, either producing crazy output, or crashing. It should,
530        of course, ignore a request for colour when reporting lines that do not
531        match.
532    
533    4.  Another pcregrep bug caused similar problems if --colour was specified with
534        -M (multiline) and the pattern match finished with a line ending.
535    
536    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
537        matched in multiline mode, the following line was shown as part of the
538        match. This seems wrong, so I have changed it.
539    
540    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
541        the check for further matches in the same line (so they could be coloured)
542        to overrun the end of the current line. If another match was found, it was
543        incorrectly shown (and then shown again when found in the next line).
544    
545    7.  If pcregrep was compiled under Windows, there was a reference to the
546        function pcregrep_exit() before it was defined. I am assuming this was
547        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
548        reported by a user. I've moved the definition above the reference.
549    
550    
551    Version 8.11 10-Dec-2010
552    ------------------------
553    
554    1.  (*THEN) was not working properly if there were untried alternatives prior
555        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
556        backtracked to try for "b" instead of moving to the next alternative branch
557        at the same level (in this case, to look for "c"). The Perl documentation
558        is clear that when (*THEN) is backtracked onto, it goes to the "next
559        alternative in the innermost enclosing group".
560    
561    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
562        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
563        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
564        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
565        (*THEN).
566    
567    3.  If \s appeared in a character class, it removed the VT character from
568        the class, even if it had been included by some previous item, for example
569        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
570        of \s, but is part of the POSIX "space" class.)
571    
572    4.  A partial match never returns an empty string (because you can always
573        match an empty string at the end of the subject); however the checking for
574        an empty string was starting at the "start of match" point. This has been
575        changed to the "earliest inspected character" point, because the returned
576        data for a partial match starts at this character. This means that, for
577        example, /(?<=abc)def/ gives a partial match for the subject "abc"
578        (previously it gave "no match").
579    
580    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
581        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
582        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
583        has an implication that the given string is incomplete (because a partial
584        match is preferred over a full match). For this reason, these items now
585        give a partial match in this situation. [Aside: previously, the one case
586        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
587        match rather than a full match, which was wrong by the old rules, but is
588        now correct.]
589    
590    6.  There was a bug in the handling of #-introduced comments, recognized when
591        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
592        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
593        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
594        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
595        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
596        places in pcre_compile().
597    
598    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
599        comments when looking ahead for named forward references to subpatterns,
600        the only newline sequence it recognized was NL. It now handles newlines
601        according to the set newline convention.
602    
603    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
604        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
605        cater for a lack of strerror(). These oversights have been fixed.
606    
607    9.  Added --match-limit and --recursion-limit to pcregrep.
608    
609    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
610    
611    11. When the -o option was used, pcregrep was setting a return code of 1, even
612        when matches were found, and --line-buffered was not being honoured.
613    
614    12. Added an optional parentheses number to the -o and --only-matching options
615        of pcregrep.
616    
617    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
618        can match an empty string. The code to do it in pcretest and pcredemo
619        needed fixing:
620    
621        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
622            only one byte after an empty string match just before CRLF (this case
623            just got forgotten; "any" and "anycrlf" were OK).
624    
625        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
626            mode when an empty string match preceded an ASCII character followed by
627            a non-ASCII character. (The code for advancing by one character rather
628            than one byte was nonsense.)
629    
630        (c) The pcredemo.c sample program did not have any code at all to handle
631            the cases when CRLF is a valid newline sequence.
632    
633    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
634        as a starting offset was within the subject string. There is now a new
635        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
636        negative or greater than the length of the string. In order to test this,
637        pcretest is extended to allow the setting of negative starting offsets.
638    
639    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
640        starting offset points to the beginning of a UTF-8 character was
641        unnecessarily clumsy. I tidied it up.
642    
643    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
644        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
645    
646    17. Nobody had reported that the --include_dir option, which was added in
647        release 7.7 should have been called --include-dir (hyphen, not underscore)
648        for compatibility with GNU grep. I have changed it to --include-dir, but
649        left --include_dir as an undocumented synonym, and the same for
650        --exclude-dir, though that is not available in GNU grep, at least as of
651        release 2.5.4.
652    
653    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
654        characters from a string of bytes) have been redefined so as not to use
655        loops, in order to improve performance in some environments. At the same
656        time, I abstracted some of the common code into auxiliary macros to save
657        repetition (this should not affect the compiled code).
658    
659    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
660        compile-time error is now given if \c is not followed by an ASCII
661        character, that is, a byte less than 128. (In EBCDIC mode, the code is
662        different, and any byte value is allowed.)
663    
664    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
665        START_OPTIMIZE option, which is now allowed at compile time - but just
666        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
667        to pcregrep and other applications that have no direct access to PCRE
668        options. The new /Y option in pcretest sets this option when calling
669        pcre_compile().
670    
671    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
672        back references. Groups containing recursive back references were forced to
673        be atomic by that change, but in the case of named groups, the amount of
674        memory required was incorrectly computed, leading to "Failed: internal
675        error: code overflow". This has been fixed.
676    
677    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
678        pcretest.c, to avoid build problems in some Borland environments.
679    
680    
681    Version 8.10 25-Jun-2010
682    ------------------------
683    
684    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
685        THEN.
686    
687    2.  (*ACCEPT) was not working when inside an atomic group.
688    
689    3.  Inside a character class, \B is treated as a literal by default, but
690        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
691        causes the error). The code is unchanged, but I tidied the documentation.
692    
693    4.  Inside a character class, PCRE always treated \R and \X as literals,
694        whereas Perl faults them if its -w option is set. I have changed PCRE so
695        that it faults them when PCRE_EXTRA is set.
696    
697    5.  Added support for \N, which always matches any character other than
698        newline. (It is the same as "." when PCRE_DOTALL is not set.)
699    
700    6.  When compiling pcregrep with newer versions of gcc which may have
701        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
702        declared with attribute warn_unused_result" were given. Just casting the
703        result to (void) does not stop the warnings; a more elaborate fudge is
704        needed. I've used a macro to implement this.
705    
706    7.  Minor change to pcretest.c to avoid a compiler warning.
707    
708    8.  Added four artifical Unicode properties to help with an option to make
709        \s etc use properties (see next item). The new properties are: Xan
710        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
711    
712    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
713        use Unicode properties. (*UCP) at the start of a pattern can be used to set
714        this option. Modified pcretest to add /W to test this facility. Added
715        REG_UCP to make it available via the POSIX interface.
716    
717    10. Added --line-buffered to pcregrep.
718    
719    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
720        studied, and the match started with a letter with a code point greater than
721        127 whose first byte was different to the first byte of the other case of
722        the letter, the other case of this starting letter was not recognized
723        (#976).
724    
725    12. If a pattern that was studied started with a repeated Unicode property
726        test, for example, \p{Nd}+, there was the theoretical possibility of
727        setting up an incorrect bitmap of starting bytes, but fortunately it could
728        not have actually happened in practice until change 8 above was made (it
729        added property types that matched character-matching opcodes).
730    
731    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
732        possible starting bytes for non-anchored patterns.
733    
734    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
735        \R, and also a number of cases that involve Unicode properties, both
736        explicit and implicit when PCRE_UCP is set.
737    
738    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
739        input, it could crash or give wrong results if characters with values
740        greater than 0xc0 were present in the subject string. (Detail: it assumed
741        UTF-8 input when processing these items.)
742    
743    16. Added a lot of (int) casts to avoid compiler warnings in systems where
744        size_t is 64-bit (#991).
745    
746    17. Added a check for running out of memory when PCRE is compiled with
747        --disable-stack-for-recursion (#990).
748    
749    18. If the last data line in a file for pcretest does not have a newline on
750        the end, a newline was missing in the output.
751    
752    19. The default pcre_chartables.c file recognizes only ASCII characters (values
753        less than 128) in its various bitmaps. However, there is a facility for
754        generating tables according to the current locale when PCRE is compiled. It
755        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
756        characters, are recognized by isspace() and therefore were getting set in
757        these tables, and indeed these tables seem to approximate to ISO 8859. This
758        caused a problem in UTF-8 mode when pcre_study() was used to create a list
759        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
760        which of course cannot start UTF-8 characters. I have changed the code so
761        that only real ASCII characters (less than 128) and the correct starting
762        bytes for UTF-8 encodings are set for characters greater than 127 when in
763        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
764        altogether.)
765    
766    20. Added the /T option to pcretest so as to be able to run tests with non-
767        standard character tables, thus making it possible to include the tests
768        used for 19 above in the standard set of tests.
769    
770    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
771        reference to a subpattern the other side of a comment that contains an
772        opening parenthesis caused either an internal compiling error, or a
773        reference to the wrong subpattern.
774    
775    
776    Version 8.02 19-Mar-2010
777    ------------------------
778    
779    1.  The Unicode data tables have been updated to Unicode 5.2.0.
780    
781    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
782        configured.
783    
784    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
785        original author of that file, following a query about its status.
786    
787    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
788        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
789    
790    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
791        quantifier applied to a forward-referencing subroutine call, could compile
792        incorrect code or give the error "internal error: previously-checked
793        referenced subpattern not found".
794    
795    6.  Both MS Visual Studio and Symbian OS have problems with initializing
796        variables to point to external functions. For these systems, therefore,
797        pcre_malloc etc. are now initialized to local functions that call the
798        relevant global functions.
799    
800    7.  There were two entries missing in the vectors called coptable and poptable
801        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
802        I've fixed the data, and added a kludgy way of testing at compile time that
803        the lengths are correct (equal to the number of opcodes).
804    
805    8.  Following on from 7, I added a similar kludge to check the length of the
806        eint vector in pcreposix.c.
807    
808    9.  Error texts for pcre_compile() are held as one long string to avoid too
809        much relocation at load time. To find a text, the string is searched,
810        counting zeros. There was no check for running off the end of the string,
811        which could happen if a new error number was added without updating the
812        string.
813    
814    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
815    
816    11. \K was not working if it appeared in an atomic group or in a group that
817        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
818        \K is "not well defined" if used in an assertion. PCRE now accepts it if
819        the assertion is positive, but not if it is negative.
820    
821    12. Change 11 fortuitously reduced the size of the stack frame used in the
822        "match()" function of pcre_exec.c by one pointer. Forthcoming
823        implementation of support for (*MARK) will need an extra pointer on the
824        stack; I have reserved it now, so that the stack frame size does not
825        decrease.
826    
827    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
828        item in branch that calls a recursion is a subroutine call - as in the
829        second branch in the above example - was incorrectly given the compile-
830        time error "recursive call could loop indefinitely" because pcre_compile()
831        was not correctly checking the subroutine for matching a non-empty string.
832    
833    14. The checks for overrunning compiling workspace could trigger after an
834        overrun had occurred. This is a "should never occur" error, but it can be
835        triggered by pathological patterns such as hundreds of nested parentheses.
836        The checks now trigger 100 bytes before the end of the workspace.
837    
838    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
839    
840    
841    Version 8.01 19-Jan-2010
842    ------------------------
843    
844    1.  If a pattern contained a conditional subpattern with only one branch (in
845        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
846        computed the wrong minimum data length (which is of course zero for such
847        subpatterns). This could cause incorrect "no match" results.
848    
849    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
850        the pattern is reset in the first branch, pcre_compile() failed with
851        "internal error: code overflow at offset...". This happened only when
852        the reset was to the original external option setting. (An optimization
853        abstracts leading options settings into an external setting, which was the
854        cause of this.)
855    
856    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
857        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
858        assertion pattern did not match (meaning that the assertion was true), it
859        was incorrectly treated as false if the SKIP had been reached during the
860        matching. This also applied to assertions used as conditions.
861    
862    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
863        assertion subpattern, including such a pattern used as a condition,
864        unpredictable results occurred, instead of the error return
865        PCRE_ERROR_DFA_UITEM.
866    
867    5.  The C++ GlobalReplace function was not working like Perl for the special
868        situation when an empty string is matched. It now does the fancy magic
869        stuff that is necessary.
870    
871    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
872        removed. (These were left over from very, very early versions of PCRE.)
873    
874    7.  Some cosmetic changes to the code to make life easier when compiling it
875        as part of something else:
876    
877        (a) Change DEBUG to PCRE_DEBUG.
878    
879        (b) In pcre_compile(), rename the member of the "branch_chain" structure
880            called "current" as "current_branch", to prevent a collision with the
881            Linux macro when compiled as a kernel module.
882    
883        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
884            prevent a collision with the Linux macro when compiled as a kernel
885            module.
886    
887    8.  In pcre_compile() there are some checks for integer overflows that used to
888        cast potentially large values to (double). This has been changed to that
889        when building, a check for int64_t is made, and if it is found, it is used
890        instead, thus avoiding the use of floating point arithmetic. (There is no
891        other use of FP in PCRE.) If int64_t is not found, the fallback is to
892        double.
893    
894    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
895        2005 (difference between two addresses compared to an unsigned value).
896    
897    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
898        custom one, because of the following reported problem in Windows:
899    
900          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
901              under Win32.
902          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
903              therefore missing the function definition.
904          - The compiler thus generates a "C" signature for the test function.
905          - The linker fails to find the "C" function.
906          - PCRE fails to configure if asked to do so against libbz2.
907    
908    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
909        messages were output:
910    
911          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
912          rerunning libtoolize, to keep the correct libtool macros in-tree.
913          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
914    
915        I have done both of these things.
916    
917    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
918        most of the time, it *can* run out if it is given a pattern that contains a
919        runaway infinite recursion. I updated the discussion in the pcrestack man
920        page.
921    
922    13. Now that we have gone to the x.xx style of version numbers, the minor
923        version may start with zero. Using 08 or 09 is a bad idea because users
924        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
925        interpreted as invalid octal numbers. I've updated the previous comment in
926        configure.ac, and also added a check that gives an error if 08 or 09 are
927        used.
928    
929    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
930        causing partial matching to fail when the end of the subject matched \W
931        in a UTF-8 pattern where \W was quantified with a minimum of 3.
932    
933    15. There were some discrepancies between the declarations in pcre_internal.h
934        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
935        their definitions. The declarations used "const uschar *" and the
936        definitions used USPTR. Even though USPTR is normally defined as "const
937        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
938        reported that: "This difference in casting confuses some C++ compilers, for
939        example, SunCC recognizes above declarations as different functions and
940        generates broken code for hbpcre." I have changed the declarations to use
941        USPTR.
942    
943    16. GNU libtool is named differently on some systems. The autogen.sh script now
944        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
945        (FreeBSD).
946    
947    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
948        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
949        comment: "Figure out how to create a longlong from a string: strtoll and
950        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
951        instance, but it only takes 2 args instead of 3!"
952    
953    18. A subtle bug concerned with back references has been fixed by a change of
954        specification, with a corresponding code fix. A pattern such as
955        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
956        refers, was giving matches when it shouldn't. For example, xa=xaaa would
957        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
958        same bug. Such groups have to be quantified to be useful, or contained
959        inside another quantified group. (If there's no repetition, the reference
960        can never match.) The problem arises because, having left the group and
961        moved on to the rest of the pattern, a later failure that backtracks into
962        the group uses the captured value from the final iteration of the group
963        rather than the correct earlier one. I have fixed this in PCRE by forcing
964        any group that contains a reference to itself to be an atomic group; that
965        is, there cannot be any backtracking into it once it has completed. This is
966        similar to recursive and subroutine calls.
967    
968    
969    Version 8.00 19-Oct-09
970    ----------------------
971    
972    1.  The table for translating pcre_compile() error codes into POSIX error codes
973        was out-of-date, and there was no check on the pcre_compile() error code
974        being within the table. This could lead to an OK return being given in
975        error.
976    
977    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
978        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
979        in a Windows environment.
980    
981    3.  The pcregrep --count option prints the count for each file even when it is
982        zero, as does GNU grep. However, pcregrep was also printing all files when
983        --files-with-matches was added. Now, when both options are given, it prints
984        counts only for those files that have at least one match. (GNU grep just
985        prints the file name in this circumstance, but including the count seems
986        more useful - otherwise, why use --count?) Also ensured that the
987        combination -clh just lists non-zero counts, with no names.
988    
989    4.  The long form of the pcregrep -F option was incorrectly implemented as
990        --fixed_strings instead of --fixed-strings. This is an incompatible change,
991        but it seems right to fix it, and I didn't think it was worth preserving
992        the old behaviour.
993    
994    5.  The command line items --regex=pattern and --regexp=pattern were not
995        recognized by pcregrep, which required --regex pattern or --regexp pattern
996        (with a space rather than an '='). The man page documented the '=' forms,
997        which are compatible with GNU grep; these now work.
998    
999    6.  No libpcreposix.pc file was created for pkg-config; there was just
1000        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1001    
1002    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1003        when UCP support is not needed, by modifying the Python script that
1004        generates it from Unicode data files. This should not matter if the module
1005        is correctly used as a library, but I received one complaint about 50K of
1006        unwanted data. My guess is that the person linked everything into his
1007        program rather than using a library. Anyway, it does no harm.
1008    
1009    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1010        was a minimum greater than 1 for a wide character in a possessive
1011        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1012        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1013        character. Chaos in the form of incorrect output or a compiling loop could
1014        result.
1015    
1016    9.  The restrictions on what a pattern can contain when partial matching is
1017        requested for pcre_exec() have been removed. All patterns can now be
1018        partially matched by this function. In addition, if there are at least two
1019        slots in the offset vector, the offset of the earliest inspected character
1020        for the match and the offset of the end of the subject are set in them when
1021        PCRE_ERROR_PARTIAL is returned.
1022    
1023    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1024        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1025        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1026        and may be more useful for multi-segment matching.
1027    
1028    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1029        used to be given if ever the end of the subject was reached; now it is
1030        given only if matching could not proceed because another character was
1031        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1032        string "Z", which now yields "no match" instead of "partial match". In the
1033        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1034        final character ended with (*FAIL).
1035    
1036    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1037        if the pattern had a "must contain" character that was already found in the
1038        earlier partial match, unless partial matching was again requested. For
1039        example, with the pattern /dog.(body)?/, the "must contain" character is
1040        "g". If the first part-match was for the string "dog", restarting with
1041        "sbody" failed. This bug has been fixed.
1042    
1043    13. The string returned by pcre_dfa_exec() after a partial match has been
1044        changed so that it starts at the first inspected character rather than the
1045        first character of the match. This makes a difference only if the pattern
1046        starts with a lookbehind assertion or \b or \B (\K is not supported by
1047        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1048        matching functions compatible, and I think it's the right thing to do.
1049    
1050    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1051        so that the demonstration program is easily available in environments where
1052        PCRE has not been installed from source.
1053    
1054    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1055        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1056        library.
1057    
1058    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1059        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1060        is not the first non-POSIX option to be added. Clearly some people find
1061        these options useful.
1062    
1063    17. If a caller to the POSIX matching function regexec() passes a non-zero
1064        value for nmatch with a NULL value for pmatch, the value of
1065        nmatch is forced to zero.
1066    
1067    18. RunGrepTest did not have a test for the availability of the -u option of
1068        the diff command, as RunTest does. It now checks in the same way as
1069        RunTest, and also checks for the -b option.
1070    
1071    19. If an odd number of negated classes containing just a single character
1072        interposed, within parentheses, between a forward reference to a named
1073        subpattern and the definition of the subpattern, compilation crashed with
1074        an internal error, complaining that it could not find the referenced
1075        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1076        [The bug was that it was starting one character too far in when skipping
1077        over the character class, thus treating the ] as data rather than
1078        terminating the class. This meant it could skip too much.]
1079    
1080    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1081        /g option in pcretest when the pattern contains \K, which makes it possible
1082        to have an empty string match not at the start, even when the pattern is
1083        anchored. Updated pcretest and pcredemo to use this option.
1084    
1085    21. If the maximum number of capturing subpatterns in a recursion was greater
1086        than the maximum at the outer level, the higher number was returned, but
1087        with unset values at the outer level. The correct (outer level) value is
1088        now given.
1089    
1090    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1091        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1092        make it do so. The string so far is captured, making this feature
1093        compatible with Perl.
1094    
1095    23. The tests have been re-organized, adding tests 11 and 12, to make it
1096        possible to check the Perl 5.10 features against Perl 5.10.
1097    
1098    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1099        pattern matches a fixed length string. PCRE did not allow this; now it
1100        does. Neither allows recursion.
1101    
1102    25. I finally figured out how to implement a request to provide the minimum
1103        length of subject string that was needed in order to match a given pattern.
1104        (It was back references and recursion that I had previously got hung up
1105        on.) This code has now been added to pcre_study(); it finds a lower bound
1106        to the length of subject needed. It is not necessarily the greatest lower
1107        bound, but using it to avoid searching strings that are too short does give
1108        some useful speed-ups. The value is available to calling programs via
1109        pcre_fullinfo().
1110    
1111    26. While implementing 25, I discovered to my embarrassment that pcretest had
1112        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1113        study optimizations had never been tested with that matching function.
1114        Oops. What is worse, even when it was passed study data, there was a bug in
1115        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1116        were also very few tests of studied patterns with pcre_dfa_exec().
1117    
1118    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1119        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1120        on the other side of the coin, they are no longer allowed to have different
1121        names, because these cannot be distinguished in PCRE, and this has caused
1122        confusion. (This is a difference from Perl.)
1123    
1124    28. When duplicate subpattern names are present (necessarily with different
1125        numbers, as required by 27 above), and a test is made by name in a
1126        conditional pattern, either for a subpattern having been matched, or for
1127        recursion in such a pattern, all the associated numbered subpatterns are
1128        tested, and the overall condition is true if the condition is true for any
1129        one of them. This is the way Perl works, and is also more like the way
1130        testing by number works.
1131    
1132    
1133    Version 7.9 11-Apr-09
1134  ---------------------  ---------------------
1135    
1136  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1137      (pcretest), all targets were linked against these libraries. This included      (pcretest), all targets were linked against these libraries. This included
1138      libpcre, libpcreposix, and libpcrecpp, even though they do not use these      libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1139      libraries. This caused unwanted dependencies to be created. This problem      libraries. This caused unwanted dependencies to be created. This problem
1140      has been fixed, and now only pcregrep is linked with bzlib/zlib and only      has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1141      pcretest is linked with readline.      pcretest is linked with readline.
1142    
1143  2.  The "typedef int BOOL" in pcre_internal.h that was included inside the  2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1144      "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been      "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1145      moved outside it again, because FALSE and TRUE are already defined in AIX,      moved outside it again, because FALSE and TRUE are already defined in AIX,
1146      but BOOL is not.      but BOOL is not.
1147    
1148  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1149      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1150    
1151  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
1152      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
1153      lines. This is not true; no spaces are inserted. I have also clarified the      lines. This is not true; no spaces are inserted. I have also clarified the
1154      wording for the --colour (or --color) option.      wording for the --colour (or --color) option.
1155    
1156  5.  When --colour was used with -o, the list of matching strings was not  5.  In pcregrep, when --colour was used with -o, the list of matching strings
1157      coloured; this is different to GNU grep, so I have changed it to be the      was not coloured; this is different to GNU grep, so I have changed it to be
1158      same.      the same.
1159    
1160    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1161        each matching line was coloured. Now it goes on to look for further matches
1162        of any of the test patterns, which is the same behaviour as GNU grep.
1163    
1164    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1165        doesn't make sense to accept an empty string match in pcregrep, so I have
1166        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1167        seems to be how GNU grep behaves.
1168    
1169    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1170        start or after a newline", because the conditional assertion was not being
1171        correctly handled. The rule now is that both the assertion and what follows
1172        in the first alternative must satisfy the test.
1173    
1174    9.  If auto-callout was enabled in a pattern with a conditional group whose
1175        condition was an assertion, PCRE could crash during matching, both with
1176        pcre_exec() and pcre_dfa_exec().
1177    
1178    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1179        used for matching.
1180    
1181    11. Unicode property support in character classes was not working for
1182        characters (bytes) greater than 127 when not in UTF-8 mode.
1183    
1184    12. Added the -M command line option to pcretest.
1185    
1186    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1187    
1188    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1189    
1190    16. Added comments and documentation about mis-use of no_arg in the C++
1191        wrapper.
1192    
1193    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1194        from Martin Jerabek that uses macro names for all relevant character and
1195        string constants.
1196    
1197    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1198        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1199        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1200        these, but not everybody uses configure.
1201    
1202    19. A conditional group that had only one branch was not being correctly
1203        recognized as an item that could match an empty string. This meant that an
1204        enclosing group might also not be so recognized, causing infinite looping
1205        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1206        with the subject "ab", where knowledge that the repeated group can match
1207        nothing is needed in order to break the loop.
1208    
1209    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1210        exec(), but without supplying a callout function, matching went wrong.
1211    
1212    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1213        leak if the size of the offset vector was greater than 30. When the vector
1214        is smaller, the saved offsets during recursion go onto a local stack
1215        vector, but for larger vectors malloc() is used. It was failing to free
1216        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1217        error, in fact).
1218    
1219    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1220        heapframe that is used only when UTF-8 support is enabled. This caused no
1221        problem, but was untidy.
1222    
1223    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1224        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1225        included within another project.
1226    
1227    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1228        slightly modified by me:
1229    
1230          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1231              not building pcregrep.
1232    
1233          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1234              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1235    
1236    25. Forward references, both numeric and by name, in patterns that made use of
1237        duplicate group numbers, could behave incorrectly or give incorrect errors,
1238        because when scanning forward to find the reference group, PCRE was not
1239        taking into account the duplicate group numbers. A pattern such as
1240        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1241    
1242    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1243        the feature of a custom pointer more persuasive (as requested by a user).
1244    
1245    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1246        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1247        pre-defined.
1248    
1249    28. Added support for (*UTF8) at the start of a pattern.
1250    
1251    29. Arrange for flags added by the "release type" setting in CMake to be shown
1252        in the configuration summary.
1253    
1254    
1255  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
1256  ---------------------  ---------------------

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