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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Improved \X and back reference partial matching.
18    
19    
20    Version 8.30 04-February-2012
21    -----------------------------
22    
23    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
24        name is defined in ctype.h.
25    
26    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
27        only in quite long subpatterns.
28    
29    3.  Removed the function pcre_info(), which has been obsolete and deprecated
30        since it was replaced by pcre_fullinfo() in February 2000.
31    
32    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
33        match a (*MARK), and the match failed at the start of the subject, a
34        reference to memory before the start of the subject could occur. This bug
35        was introduced by fix 17 of release 8.21.
36    
37    5.  A reference to an unset group with zero minimum repetition was giving
38        totally wrong answers (in non-JavaScript-compatibility mode). For example,
39        /(another)?(\1?)test/ matched against "hello world test". This bug was
40        introduced in release 8.13.
41    
42    6.  Add support for 16-bit character strings (a large amount of work involving
43        many changes and refactorings).
44    
45    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
46        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
47        from a file.
48    
49    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
50        rounding is not applied in this particular case).
51    
52    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
53        if they appear, or are escaped, in patterns.
54    
55    10. Get rid of a number of -Wunused-but-set-variable warnings.
56    
57    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
58        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
59        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
60        also returns the mark "x". This bug applied to capturing parentheses,
61        non-capturing parentheses, and atomic parentheses. It also applied to some
62        assertions.
63    
64    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
65        information out of configure.ac instead of relying on pcre.h.generic, which
66        is not stored in the repository.
67    
68    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
69        -lreadline.
70    
71    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
72    
73    15. Applied Graycode's patch to put the top-level frame on the stack rather
74        than the heap when not using the stack for recursion. This gives a
75        performance improvement in many cases when recursion is not deep.
76    
77    16. Experimental code added to "pcretest -C" to output the stack frame size.
78    
79    
80    Version 8.21 12-Dec-2011
81    ------------------------
82    
83    1.  Updating the JIT compiler.
84    
85    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
86        are added as well.
87    
88    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
89        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
90        calling _pcre_jit_exec. Some extra comments are added.
91    
92    4.  (*MARK) settings inside atomic groups that do not contain any capturing
93        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
94        was introduced by change 18 for 8.20.
95    
96    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
97        ECMA-262 standard.
98    
99    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
100        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
101        This bug was probably introduced by change 9 of 8.13.
102    
103    7.  While fixing 6 above, I noticed that a number of other items were being
104        incorrectly rejected as "not fixed length". This arose partly because newer
105        opcodes had not been added to the fixed-length checking code. I have (a)
106        corrected the bug and added tests for these items, and (b) arranged for an
107        error to occur if an unknown opcode is encountered while checking for fixed
108        length instead of just assuming "not fixed length". The items that were
109        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
110        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
111        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
112    
113    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
114        being incorrectly compiled and would have given unpredicatble results.
115    
116    9.  A possessively repeated subpattern with minimum repeat count greater than
117        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
118        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
119        the first (A) could occur when it should not.
120    
121    10. Add a cast and remove a redundant test from the code.
122    
123    11. JIT should use pcre_malloc/pcre_free for allocation.
124    
125    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
126        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
127        is anything other than /usr, -L is still shown).
128    
129    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
130    
131    14. Perl does not support \N without a following name in a [] class; PCRE now
132        also gives an error.
133    
134    15. If a forward reference was repeated with an upper limit of around 2000,
135        it caused the error "internal error: overran compiling workspace". The
136        maximum number of forward references (including repeats) was limited by the
137        internal workspace, and dependent on the LINK_SIZE. The code has been
138        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
139        the default depends on LINK_SIZE. There is a new upper limit (for safety)
140        of around 200,000 forward references. While doing this, I also speeded up
141        the filling in of repeated forward references.
142    
143    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
144        incorrectly expecting the subject to contain another "a" after the start.
145    
146    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
147        in the match, the SKIP should be ignored. This was not happening; instead
148        the SKIP was being treated as NOMATCH. For patterns such as
149        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
150        tested.
151    
152    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
153        now much more compatible with Perl, in particular in cases where the result
154        is a non-match for a non-anchored pattern. For example, if
155        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
156        "m", where previously it did not return a name. A side effect of this
157        change is that for partial matches, the last encountered mark name is
158        returned, as for non matches. A number of tests that were previously not
159        Perl-compatible have been moved into the Perl-compatible test files. The
160        refactoring has had the pleasing side effect of removing one argument from
161        the match() function, thus reducing its stack requirements.
162    
163    19. If the /S+ option was used in pcretest to study a pattern using JIT,
164        subsequent uses of /S (without +) incorrectly behaved like /S+.
165    
166    21. Retrieve executable code size support for the JIT compiler and fixing
167        some warnings.
168    
169    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
170        not work when the shorter character appeared right at the end of the
171        subject string.
172    
173    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
174        systems.
175    
176    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
177        output it when the /M option is used in pcretest.
178    
179    25. The CheckMan script was not being included in the distribution. Also, added
180        an explicit "perl" to run Perl scripts from the PrepareRelease script
181        because this is reportedly needed in Windows.
182    
183    26. If study data was being save in a file and studying had not found a set of
184        "starts with" bytes for the pattern, the data written to the file (though
185        never used) was taken from uninitialized memory and so caused valgrind to
186        complain.
187    
188    27. Updated RunTest.bat as provided by Sheri Pierce.
189    
190    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
191    
192    29. Computation of memory usage for the table of capturing group names was
193        giving an unnecessarily large value.
194    
195    
196    Version 8.20 21-Oct-2011
197    ------------------------
198    
199    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
200        a POSIX class. After further experiments with Perl, which convinced me that
201        Perl has bugs and confusions, a closing square bracket is no longer allowed
202        in a POSIX name. This bug also affected patterns with classes that started
203        with full stops.
204    
205    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
206        captured substring, but while checking the failing first alternative,
207        substring 1 is temporarily captured. If the output vector supplied to
208        pcre_exec() was not big enough for this capture, the yield of the function
209        was still zero ("insufficient space for captured substrings"). This cannot
210        be totally fixed without adding another stack variable, which seems a lot
211        of expense for a edge case. However, I have improved the situation in cases
212        such as /(a)(b)x|abc/ matched against "abc", where the return code
213        indicates that fewer than the maximum number of slots in the ovector have
214        been set.
215    
216    3.  Related to (2) above: when there are more back references in a pattern than
217        slots in the output vector, pcre_exec() uses temporary memory during
218        matching, and copies in the captures as far as possible afterwards. It was
219        using the entire output vector, but this conflicts with the specification
220        that only 2/3 is used for passing back captured substrings. Now it uses
221        only the first 2/3, for compatibility. This is, of course, another edge
222        case.
223    
224    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
225        main code base, and can be used by building with --enable-jit. When this is
226        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
227        runtime --no-jit option is given.
228    
229    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
230        ovector, the return from the function was zero, implying that there were
231        other matches that did not fit. The correct "exactly full" value is now
232        returned.
233    
234    6.  If a subpattern that was called recursively or as a subroutine contained
235        (*PRUNE) or any other control that caused it to give a non-standard return,
236        invalid errors such as "Error -26 (nested recursion at the same subject
237        position)" or even infinite loops could occur.
238    
239    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
240        computing the minimum length on reaching *ACCEPT, and so ended up with the
241        wrong value of 1 rather than 0. Further investigation indicates that
242        computing a minimum subject length in the presence of *ACCEPT is difficult
243        (think back references, subroutine calls), and so I have changed the code
244        so that no minimum is registered for a pattern that contains *ACCEPT.
245    
246    8.  If (*THEN) was present in the first (true) branch of a conditional group,
247        it was not handled as intended. [But see 16 below.]
248    
249    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
250        Sheri Pierce.
251    
252    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
253        the first byte in a match must be "a".
254    
255    11. Change 17 for 8.13 increased the recursion depth for patterns like
256        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
257        pattern contains any instances of (*THEN). If it does not, the old
258        optimizations are restored. It would be nice to do this on a per-group
259        basis, but at the moment that is not feasible.
260    
261    12. In some environments, the output of pcretest -C is CRLF terminated. This
262        broke RunTest's code that checks for the link size. A single white space
263        character after the value is now allowed for.
264    
265    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
266        For "fr", it uses the Windows-specific input and output files.
267    
268    14. If (*THEN) appeared in a group that was called recursively or as a
269        subroutine, it did not work as intended. [But see next item.]
270    
271    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
272        pattern fragments (but not containing any | characters). If A and B are
273        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
274        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
275        D. In other words, Perl considers parentheses that do not contain any |
276        characters to be part of a surrounding alternative, whereas PCRE was
277        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
278        differently. PCRE now behaves in the same way as Perl, except in the case
279        of subroutine/recursion calls such as (?1) which have in any case always
280        been different (but PCRE had them first :-).
281    
282    16. Related to 15 above: Perl does not treat the | in a conditional group as
283        creating alternatives. Such a group is treated in the same way as an
284        ordinary group without any | characters when processing (*THEN). PCRE has
285        been changed to match Perl's behaviour.
286    
287    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
288        RunGrepTest script failed.
289    
290    18. Change 22 for version 13 caused atomic groups to use more stack. This is
291        inevitable for groups that contain captures, but it can lead to a lot of
292        stack use in large patterns. The old behaviour has been restored for atomic
293        groups that do not contain any capturing parentheses.
294    
295    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
296        suppress the check for a minimum subject length at run time. (If it was
297        given to pcre_exec() or pcre_dfa_exec() it did work.)
298    
299    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
300        fail to work when decoding hex characters in data strings in EBCDIC
301        environments.
302    
303    21. It appears that in at least one Mac OS environment, the isxdigit() function
304        is implemented as a macro that evaluates to its argument more than once,
305        contravening the C 90 Standard (I haven't checked a later standard). There
306        was an instance in pcretest which caused it to go wrong when processing
307        \x{...} escapes in subject strings. The has been rewritten to avoid using
308        things like p++ in the argument of isxdigit().
309    
310    
311    Version 8.13 16-Aug-2011
312    ------------------------
313    
314    1.  The Unicode data tables have been updated to Unicode 6.0.0.
315    
316    2.  Two minor typos in pcre_internal.h have been fixed.
317    
318    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
319        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
320        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
321    
322    4.  There were a number of related bugs in the code for matching backrefences
323        caselessly in UTF-8 mode when codes for the characters concerned were
324        different numbers of bytes. For example, U+023A and U+2C65 are an upper
325        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
326        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
327        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
328        2-byte code at the end of the subject (it thought there wasn't enough data
329        left).
330    
331    5.  Comprehensive information about what went wrong is now returned by
332        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
333        as the output vector has at least 2 elements. The offset of the start of
334        the failing character and a reason code are placed in the vector.
335    
336    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
337        now returned is for the first byte of the failing character, instead of the
338        last byte inspected. This is an incompatible change, but I hope it is small
339        enough not to be a problem. It makes the returned offset consistent with
340        pcre_exec() and pcre_dfa_exec().
341    
342    7.  pcretest now gives a text phrase as well as the error number when
343        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
344        failure, the offset and reason code are output.
345    
346    8.  When \R was used with a maximizing quantifier it failed to skip backwards
347        over a \r\n pair if the subsequent match failed. Instead, it just skipped
348        back over a single character (\n). This seems wrong (because it treated the
349        two characters as a single entity when going forwards), conflicts with the
350        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
351        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
352        has been changed.
353    
354    9.  Some internal refactoring has changed the processing so that the handling
355        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
356        time (the PCRE_DOTALL option was changed this way some time ago: version
357        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
358        which was always a bit of a fudge. It also means that there is one less
359        argument for the match() function, which reduces its stack requirements
360        slightly. This change also fixes an incompatibility with Perl: the pattern
361        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
362    
363    10. More internal refactoring has drastically reduced the number of recursive
364        calls to match() for possessively repeated groups such as (abc)++ when
365        using pcre_exec().
366    
367    11. While implementing 10, a number of bugs in the handling of groups were
368        discovered and fixed:
369    
370        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
371        (a|)*(?1) gave a compile-time internal error.
372        ((a|)+)+  did not notice that the outer group could match an empty string.
373        (^a|^)+   was not marked as anchored.
374        (.*a|.*)+ was not marked as matching at start or after a newline.
375    
376    12. Yet more internal refactoring has removed another argument from the match()
377        function. Special calls to this function are now indicated by setting a
378        value in a variable in the "match data" data block.
379    
380    13. Be more explicit in pcre_study() instead of relying on "default" for
381        opcodes that mean there is no starting character; this means that when new
382        ones are added and accidentally left out of pcre_study(), testing should
383        pick them up.
384    
385    14. The -s option of pcretest has been documented for ages as being an old
386        synonym of -m (show memory usage). I have changed it to mean "force study
387        for every regex", that is, assume /S for every regex. This is similar to -i
388        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
389        using it. It makes it easier to run collections of tests with and without
390        study enabled, and thereby test pcre_study() more easily. All the standard
391        tests are now run with and without -s (but some patterns can be marked as
392        "never study" - see 20 below).
393    
394    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
395        restoration of the capturing data to the outer values was not happening
396        correctly.
397    
398    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
399        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
400        pattern had matched an empty string, and so incorrectly returned a no
401        match.
402    
403    17. There was optimizing code for the last branch of non-capturing parentheses,
404        and also for the obeyed branch of a conditional subexpression, which used
405        tail recursion to cut down on stack usage. Unfortunately, now that there is
406        the possibility of (*THEN) occurring in these branches, tail recursion is
407        no longer possible because the return has to be checked for (*THEN). These
408        two optimizations have therefore been removed. [But see 8.20/11 above.]
409    
410    18. If a pattern containing \R was studied, it was assumed that \R always
411        matched two bytes, thus causing the minimum subject length to be
412        incorrectly computed because \R can also match just one byte.
413    
414    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
415        was incorrectly computed.
416    
417    20. If /S is present twice on a test pattern in pcretest input, it now
418        *disables* studying, thereby overriding the use of -s on the command line
419        (see 14 above). This is necessary for one or two tests to keep the output
420        identical in both cases.
421    
422    21. When (*ACCEPT) was used in an assertion that matched an empty string and
423        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
424    
425    22. When an atomic group that contained a capturing parenthesis was
426        successfully matched, but the branch in which it appeared failed, the
427        capturing was not being forgotten if a higher numbered group was later
428        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
429        group 1 to "a", when in fact it should be unset. This applied to multi-
430        branched capturing and non-capturing groups, repeated or not, and also to
431        positive assertions (capturing in negative assertions does not happen
432        in PCRE) and also to nested atomic groups.
433    
434    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
435        subject after a captured substring, to make it easier to tell which of a
436        number of identical substrings has been captured.
437    
438    24. The way atomic groups are processed by pcre_exec() has been changed so that
439        if they are repeated, backtracking one repetition now resets captured
440        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
441        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
442        "aaa". Previously, it would have been "a". As part of this code
443        refactoring, the way recursive calls are handled has also been changed.
444    
445    25. If an assertion condition captured any substrings, they were not passed
446        back unless some other capturing happened later. For example, if
447        (?(?=(a))a) was matched against "a", no capturing was returned.
448    
449    26. When studying a pattern that contained subroutine calls or assertions,
450        the code for finding the minimum length of a possible match was handling
451        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
452        group 1 called group 2 while simultaneously a separate group 2 called group
453        1). A stack overflow occurred in this case. I have fixed this by limiting
454        the recursion depth to 10.
455    
456    27. Updated RunTest.bat in the distribution to the version supplied by Tom
457        Fortmann. This supports explicit test numbers on the command line, and has
458        argument validation and error reporting.
459    
460    28. An instance of \X with an unlimited repeat could fail if at any point the
461        first character it looked at was a mark character.
462    
463    29. Some minor code refactoring concerning Unicode properties and scripts
464        should reduce the stack requirement of match() slightly.
465    
466    30. Added the '=' option to pcretest to check the setting of unused capturing
467        slots at the end of the pattern, which are documented as being -1, but are
468        not included in the return count.
469    
470    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
471        compiled something random. Now it gives a compile-time error (as does
472        Perl).
473    
474    32. A *MARK encountered during the processing of a positive assertion is now
475        recorded and passed back (compatible with Perl).
476    
477    33. If --only-matching or --colour was set on a pcregrep call whose pattern
478        had alternative anchored branches, the search for a second match in a line
479        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
480        matched the line "0102" twice. The same bug affected patterns that started
481        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
482        twice.
483    
484    34. Previously, PCRE did not allow quantification of assertions. However, Perl
485        does, and because of capturing effects, quantifying parenthesized
486        assertions may at times be useful. Quantifiers are now allowed for
487        parenthesized assertions.
488    
489    35. A minor code tidy in pcre_compile() when checking options for \R usage.
490    
491    36. \g was being checked for fancy things in a character class, when it should
492        just be a literal "g".
493    
494    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
495        appearance of a nested POSIX class supersedes an apparent external class.
496        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
497        unescaped square brackets may also appear as part of class names. For
498        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
499        more like Perl. (But see 8.20/1 above.)
500    
501    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
502        was because it thought it was \N{name}, which is not supported).
503    
504    39. Add minix to OS list not supporting the -S option in pcretest.
505    
506    40. PCRE tries to detect cases of infinite recursion at compile time, but it
507        cannot analyze patterns in sufficient detail to catch mutual recursions
508        such as ((?1))((?2)). There is now a runtime test that gives an error if a
509        subgroup is called recursively as a subpattern for a second time at the
510        same position in the subject string. In previous releases this might have
511        been caught by the recursion limit, or it might have run out of stack.
512    
513    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
514        happen only once. PCRE was, however incorrectly giving a compile time error
515        "recursive call could loop indefinitely" because it cannot analyze the
516        pattern in sufficient detail. The compile time test no longer happens when
517        PCRE is compiling a conditional subpattern, but actual runaway loops are
518        now caught at runtime (see 40 above).
519    
520    42. It seems that Perl allows any characters other than a closing parenthesis
521        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
522        has been changed to be the same.
523    
524    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
525        as not to get warnings when autogen.sh is called. Also changed
526        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
527    
528    44. To help people who use pcregrep to scan files containing exceedingly long
529        lines, the following changes have been made:
530    
531        (a) The default value of the buffer size parameter has been increased from
532            8K to 20K. (The actual buffer used is three times this size.)
533    
534        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
535            PCRE is built.
536    
537        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
538            to be set at run time.
539    
540        (d) Numerical values in pcregrep options can be followed by K or M, for
541            example --buffer-size=50K.
542    
543        (e) If a line being scanned overflows pcregrep's buffer, an error is now
544            given and the return code is set to 2.
545    
546    45. Add a pointer to the latest mark to the callout data block.
547    
548    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
549        partial match of an empty string instead of no match. This was specific to
550        the use of ".".
551    
552    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
553        complete match instead of a partial match. This bug was dependent on both
554        the PCRE_UTF8 and PCRE_DOTALL options being set.
555    
556    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
557        starting byte set, because \b was not being ignored.
558    
559    
560    Version 8.12 15-Jan-2011
561    ------------------------
562    
563    1.  Fixed some typos in the markup of the man pages, and wrote a script that
564        checks for such things as part of the documentation building process.
565    
566    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
567        --match-limit and --recursion-limit options (added for 8.11). In
568        particular, this made one of the standard tests fail. (The integer value
569        went into the wrong half of a long int.)
570    
571    3.  If the --colour option was given to pcregrep with -v (invert match), it
572        did strange things, either producing crazy output, or crashing. It should,
573        of course, ignore a request for colour when reporting lines that do not
574        match.
575    
576    4.  Another pcregrep bug caused similar problems if --colour was specified with
577        -M (multiline) and the pattern match finished with a line ending.
578    
579    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
580        matched in multiline mode, the following line was shown as part of the
581        match. This seems wrong, so I have changed it.
582    
583    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
584        the check for further matches in the same line (so they could be coloured)
585        to overrun the end of the current line. If another match was found, it was
586        incorrectly shown (and then shown again when found in the next line).
587    
588    7.  If pcregrep was compiled under Windows, there was a reference to the
589        function pcregrep_exit() before it was defined. I am assuming this was
590        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
591        reported by a user. I've moved the definition above the reference.
592    
593    
594    Version 8.11 10-Dec-2010
595    ------------------------
596    
597    1.  (*THEN) was not working properly if there were untried alternatives prior
598        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
599        backtracked to try for "b" instead of moving to the next alternative branch
600        at the same level (in this case, to look for "c"). The Perl documentation
601        is clear that when (*THEN) is backtracked onto, it goes to the "next
602        alternative in the innermost enclosing group".
603    
604    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
605        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
606        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
607        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
608        (*THEN).
609    
610    3.  If \s appeared in a character class, it removed the VT character from
611        the class, even if it had been included by some previous item, for example
612        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
613        of \s, but is part of the POSIX "space" class.)
614    
615    4.  A partial match never returns an empty string (because you can always
616        match an empty string at the end of the subject); however the checking for
617        an empty string was starting at the "start of match" point. This has been
618        changed to the "earliest inspected character" point, because the returned
619        data for a partial match starts at this character. This means that, for
620        example, /(?<=abc)def/ gives a partial match for the subject "abc"
621        (previously it gave "no match").
622    
623    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
624        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
625        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
626        has an implication that the given string is incomplete (because a partial
627        match is preferred over a full match). For this reason, these items now
628        give a partial match in this situation. [Aside: previously, the one case
629        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
630        match rather than a full match, which was wrong by the old rules, but is
631        now correct.]
632    
633    6.  There was a bug in the handling of #-introduced comments, recognized when
634        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
635        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
636        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
637        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
638        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
639        places in pcre_compile().
640    
641    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
642        comments when looking ahead for named forward references to subpatterns,
643        the only newline sequence it recognized was NL. It now handles newlines
644        according to the set newline convention.
645    
646    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
647        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
648        cater for a lack of strerror(). These oversights have been fixed.
649    
650    9.  Added --match-limit and --recursion-limit to pcregrep.
651    
652    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
653    
654    11. When the -o option was used, pcregrep was setting a return code of 1, even
655        when matches were found, and --line-buffered was not being honoured.
656    
657    12. Added an optional parentheses number to the -o and --only-matching options
658        of pcregrep.
659    
660    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
661        can match an empty string. The code to do it in pcretest and pcredemo
662        needed fixing:
663    
664        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
665            only one byte after an empty string match just before CRLF (this case
666            just got forgotten; "any" and "anycrlf" were OK).
667    
668        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
669            mode when an empty string match preceded an ASCII character followed by
670            a non-ASCII character. (The code for advancing by one character rather
671            than one byte was nonsense.)
672    
673        (c) The pcredemo.c sample program did not have any code at all to handle
674            the cases when CRLF is a valid newline sequence.
675    
676    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
677        as a starting offset was within the subject string. There is now a new
678        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
679        negative or greater than the length of the string. In order to test this,
680        pcretest is extended to allow the setting of negative starting offsets.
681    
682    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
683        starting offset points to the beginning of a UTF-8 character was
684        unnecessarily clumsy. I tidied it up.
685    
686    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
687        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
688    
689    17. Nobody had reported that the --include_dir option, which was added in
690        release 7.7 should have been called --include-dir (hyphen, not underscore)
691        for compatibility with GNU grep. I have changed it to --include-dir, but
692        left --include_dir as an undocumented synonym, and the same for
693        --exclude-dir, though that is not available in GNU grep, at least as of
694        release 2.5.4.
695    
696    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
697        characters from a string of bytes) have been redefined so as not to use
698        loops, in order to improve performance in some environments. At the same
699        time, I abstracted some of the common code into auxiliary macros to save
700        repetition (this should not affect the compiled code).
701    
702    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
703        compile-time error is now given if \c is not followed by an ASCII
704        character, that is, a byte less than 128. (In EBCDIC mode, the code is
705        different, and any byte value is allowed.)
706    
707    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
708        START_OPTIMIZE option, which is now allowed at compile time - but just
709        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
710        to pcregrep and other applications that have no direct access to PCRE
711        options. The new /Y option in pcretest sets this option when calling
712        pcre_compile().
713    
714    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
715        back references. Groups containing recursive back references were forced to
716        be atomic by that change, but in the case of named groups, the amount of
717        memory required was incorrectly computed, leading to "Failed: internal
718        error: code overflow". This has been fixed.
719    
720    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
721        pcretest.c, to avoid build problems in some Borland environments.
722    
723    
724    Version 8.10 25-Jun-2010
725    ------------------------
726    
727    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
728        THEN.
729    
730    2.  (*ACCEPT) was not working when inside an atomic group.
731    
732    3.  Inside a character class, \B is treated as a literal by default, but
733        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
734        causes the error). The code is unchanged, but I tidied the documentation.
735    
736    4.  Inside a character class, PCRE always treated \R and \X as literals,
737        whereas Perl faults them if its -w option is set. I have changed PCRE so
738        that it faults them when PCRE_EXTRA is set.
739    
740    5.  Added support for \N, which always matches any character other than
741        newline. (It is the same as "." when PCRE_DOTALL is not set.)
742    
743    6.  When compiling pcregrep with newer versions of gcc which may have
744        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
745        declared with attribute warn_unused_result" were given. Just casting the
746        result to (void) does not stop the warnings; a more elaborate fudge is
747        needed. I've used a macro to implement this.
748    
749    7.  Minor change to pcretest.c to avoid a compiler warning.
750    
751    8.  Added four artifical Unicode properties to help with an option to make
752        \s etc use properties (see next item). The new properties are: Xan
753        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
754    
755    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
756        use Unicode properties. (*UCP) at the start of a pattern can be used to set
757        this option. Modified pcretest to add /W to test this facility. Added
758        REG_UCP to make it available via the POSIX interface.
759    
760    10. Added --line-buffered to pcregrep.
761    
762    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
763        studied, and the match started with a letter with a code point greater than
764        127 whose first byte was different to the first byte of the other case of
765        the letter, the other case of this starting letter was not recognized
766        (#976).
767    
768    12. If a pattern that was studied started with a repeated Unicode property
769        test, for example, \p{Nd}+, there was the theoretical possibility of
770        setting up an incorrect bitmap of starting bytes, but fortunately it could
771        not have actually happened in practice until change 8 above was made (it
772        added property types that matched character-matching opcodes).
773    
774    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
775        possible starting bytes for non-anchored patterns.
776    
777    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
778        \R, and also a number of cases that involve Unicode properties, both
779        explicit and implicit when PCRE_UCP is set.
780    
781    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
782        input, it could crash or give wrong results if characters with values
783        greater than 0xc0 were present in the subject string. (Detail: it assumed
784        UTF-8 input when processing these items.)
785    
786    16. Added a lot of (int) casts to avoid compiler warnings in systems where
787        size_t is 64-bit (#991).
788    
789    17. Added a check for running out of memory when PCRE is compiled with
790        --disable-stack-for-recursion (#990).
791    
792    18. If the last data line in a file for pcretest does not have a newline on
793        the end, a newline was missing in the output.
794    
795    19. The default pcre_chartables.c file recognizes only ASCII characters (values
796        less than 128) in its various bitmaps. However, there is a facility for
797        generating tables according to the current locale when PCRE is compiled. It
798        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
799        characters, are recognized by isspace() and therefore were getting set in
800        these tables, and indeed these tables seem to approximate to ISO 8859. This
801        caused a problem in UTF-8 mode when pcre_study() was used to create a list
802        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
803        which of course cannot start UTF-8 characters. I have changed the code so
804        that only real ASCII characters (less than 128) and the correct starting
805        bytes for UTF-8 encodings are set for characters greater than 127 when in
806        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
807        altogether.)
808    
809    20. Added the /T option to pcretest so as to be able to run tests with non-
810        standard character tables, thus making it possible to include the tests
811        used for 19 above in the standard set of tests.
812    
813    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
814        reference to a subpattern the other side of a comment that contains an
815        opening parenthesis caused either an internal compiling error, or a
816        reference to the wrong subpattern.
817    
818    
819    Version 8.02 19-Mar-2010
820    ------------------------
821    
822    1.  The Unicode data tables have been updated to Unicode 5.2.0.
823    
824    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
825        configured.
826    
827    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
828        original author of that file, following a query about its status.
829    
830    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
831        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
832    
833    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
834        quantifier applied to a forward-referencing subroutine call, could compile
835        incorrect code or give the error "internal error: previously-checked
836        referenced subpattern not found".
837    
838    6.  Both MS Visual Studio and Symbian OS have problems with initializing
839        variables to point to external functions. For these systems, therefore,
840        pcre_malloc etc. are now initialized to local functions that call the
841        relevant global functions.
842    
843    7.  There were two entries missing in the vectors called coptable and poptable
844        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
845        I've fixed the data, and added a kludgy way of testing at compile time that
846        the lengths are correct (equal to the number of opcodes).
847    
848    8.  Following on from 7, I added a similar kludge to check the length of the
849        eint vector in pcreposix.c.
850    
851    9.  Error texts for pcre_compile() are held as one long string to avoid too
852        much relocation at load time. To find a text, the string is searched,
853        counting zeros. There was no check for running off the end of the string,
854        which could happen if a new error number was added without updating the
855        string.
856    
857    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
858    
859    11. \K was not working if it appeared in an atomic group or in a group that
860        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
861        \K is "not well defined" if used in an assertion. PCRE now accepts it if
862        the assertion is positive, but not if it is negative.
863    
864    12. Change 11 fortuitously reduced the size of the stack frame used in the
865        "match()" function of pcre_exec.c by one pointer. Forthcoming
866        implementation of support for (*MARK) will need an extra pointer on the
867        stack; I have reserved it now, so that the stack frame size does not
868        decrease.
869    
870    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
871        item in branch that calls a recursion is a subroutine call - as in the
872        second branch in the above example - was incorrectly given the compile-
873        time error "recursive call could loop indefinitely" because pcre_compile()
874        was not correctly checking the subroutine for matching a non-empty string.
875    
876    14. The checks for overrunning compiling workspace could trigger after an
877        overrun had occurred. This is a "should never occur" error, but it can be
878        triggered by pathological patterns such as hundreds of nested parentheses.
879        The checks now trigger 100 bytes before the end of the workspace.
880    
881    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
882    
883    
884    Version 8.01 19-Jan-2010
885    ------------------------
886    
887    1.  If a pattern contained a conditional subpattern with only one branch (in
888        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
889        computed the wrong minimum data length (which is of course zero for such
890        subpatterns). This could cause incorrect "no match" results.
891    
892    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
893        the pattern is reset in the first branch, pcre_compile() failed with
894        "internal error: code overflow at offset...". This happened only when
895        the reset was to the original external option setting. (An optimization
896        abstracts leading options settings into an external setting, which was the
897        cause of this.)
898    
899    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
900        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
901        assertion pattern did not match (meaning that the assertion was true), it
902        was incorrectly treated as false if the SKIP had been reached during the
903        matching. This also applied to assertions used as conditions.
904    
905    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
906        assertion subpattern, including such a pattern used as a condition,
907        unpredictable results occurred, instead of the error return
908        PCRE_ERROR_DFA_UITEM.
909    
910    5.  The C++ GlobalReplace function was not working like Perl for the special
911        situation when an empty string is matched. It now does the fancy magic
912        stuff that is necessary.
913    
914    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
915        removed. (These were left over from very, very early versions of PCRE.)
916    
917    7.  Some cosmetic changes to the code to make life easier when compiling it
918        as part of something else:
919    
920        (a) Change DEBUG to PCRE_DEBUG.
921    
922        (b) In pcre_compile(), rename the member of the "branch_chain" structure
923            called "current" as "current_branch", to prevent a collision with the
924            Linux macro when compiled as a kernel module.
925    
926        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
927            prevent a collision with the Linux macro when compiled as a kernel
928            module.
929    
930    8.  In pcre_compile() there are some checks for integer overflows that used to
931        cast potentially large values to (double). This has been changed to that
932        when building, a check for int64_t is made, and if it is found, it is used
933        instead, thus avoiding the use of floating point arithmetic. (There is no
934        other use of FP in PCRE.) If int64_t is not found, the fallback is to
935        double.
936    
937    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
938        2005 (difference between two addresses compared to an unsigned value).
939    
940    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
941        custom one, because of the following reported problem in Windows:
942    
943          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
944              under Win32.
945          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
946              therefore missing the function definition.
947          - The compiler thus generates a "C" signature for the test function.
948          - The linker fails to find the "C" function.
949          - PCRE fails to configure if asked to do so against libbz2.
950    
951    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
952        messages were output:
953    
954          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
955          rerunning libtoolize, to keep the correct libtool macros in-tree.
956          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
957    
958        I have done both of these things.
959    
960    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
961        most of the time, it *can* run out if it is given a pattern that contains a
962        runaway infinite recursion. I updated the discussion in the pcrestack man
963        page.
964    
965    13. Now that we have gone to the x.xx style of version numbers, the minor
966        version may start with zero. Using 08 or 09 is a bad idea because users
967        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
968        interpreted as invalid octal numbers. I've updated the previous comment in
969        configure.ac, and also added a check that gives an error if 08 or 09 are
970        used.
971    
972    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
973        causing partial matching to fail when the end of the subject matched \W
974        in a UTF-8 pattern where \W was quantified with a minimum of 3.
975    
976    15. There were some discrepancies between the declarations in pcre_internal.h
977        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
978        their definitions. The declarations used "const uschar *" and the
979        definitions used USPTR. Even though USPTR is normally defined as "const
980        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
981        reported that: "This difference in casting confuses some C++ compilers, for
982        example, SunCC recognizes above declarations as different functions and
983        generates broken code for hbpcre." I have changed the declarations to use
984        USPTR.
985    
986    16. GNU libtool is named differently on some systems. The autogen.sh script now
987        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
988        (FreeBSD).
989    
990    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
991        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
992        comment: "Figure out how to create a longlong from a string: strtoll and
993        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
994        instance, but it only takes 2 args instead of 3!"
995    
996    18. A subtle bug concerned with back references has been fixed by a change of
997        specification, with a corresponding code fix. A pattern such as
998        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
999        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1000        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1001        same bug. Such groups have to be quantified to be useful, or contained
1002        inside another quantified group. (If there's no repetition, the reference
1003        can never match.) The problem arises because, having left the group and
1004        moved on to the rest of the pattern, a later failure that backtracks into
1005        the group uses the captured value from the final iteration of the group
1006        rather than the correct earlier one. I have fixed this in PCRE by forcing
1007        any group that contains a reference to itself to be an atomic group; that
1008        is, there cannot be any backtracking into it once it has completed. This is
1009        similar to recursive and subroutine calls.
1010    
1011    
1012    Version 8.00 19-Oct-09
1013    ----------------------
1014    
1015    1.  The table for translating pcre_compile() error codes into POSIX error codes
1016        was out-of-date, and there was no check on the pcre_compile() error code
1017        being within the table. This could lead to an OK return being given in
1018        error.
1019    
1020    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1021        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1022        in a Windows environment.
1023    
1024    3.  The pcregrep --count option prints the count for each file even when it is
1025        zero, as does GNU grep. However, pcregrep was also printing all files when
1026        --files-with-matches was added. Now, when both options are given, it prints
1027        counts only for those files that have at least one match. (GNU grep just
1028        prints the file name in this circumstance, but including the count seems
1029        more useful - otherwise, why use --count?) Also ensured that the
1030        combination -clh just lists non-zero counts, with no names.
1031    
1032    4.  The long form of the pcregrep -F option was incorrectly implemented as
1033        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1034        but it seems right to fix it, and I didn't think it was worth preserving
1035        the old behaviour.
1036    
1037    5.  The command line items --regex=pattern and --regexp=pattern were not
1038        recognized by pcregrep, which required --regex pattern or --regexp pattern
1039        (with a space rather than an '='). The man page documented the '=' forms,
1040        which are compatible with GNU grep; these now work.
1041    
1042    6.  No libpcreposix.pc file was created for pkg-config; there was just
1043        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1044    
1045    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1046        when UCP support is not needed, by modifying the Python script that
1047        generates it from Unicode data files. This should not matter if the module
1048        is correctly used as a library, but I received one complaint about 50K of
1049        unwanted data. My guess is that the person linked everything into his
1050        program rather than using a library. Anyway, it does no harm.
1051    
1052    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1053        was a minimum greater than 1 for a wide character in a possessive
1054        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1055        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1056        character. Chaos in the form of incorrect output or a compiling loop could
1057        result.
1058    
1059    9.  The restrictions on what a pattern can contain when partial matching is
1060        requested for pcre_exec() have been removed. All patterns can now be
1061        partially matched by this function. In addition, if there are at least two
1062        slots in the offset vector, the offset of the earliest inspected character
1063        for the match and the offset of the end of the subject are set in them when
1064        PCRE_ERROR_PARTIAL is returned.
1065    
1066    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1067        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1068        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1069        and may be more useful for multi-segment matching.
1070    
1071    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1072        used to be given if ever the end of the subject was reached; now it is
1073        given only if matching could not proceed because another character was
1074        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1075        string "Z", which now yields "no match" instead of "partial match". In the
1076        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1077        final character ended with (*FAIL).
1078    
1079    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1080        if the pattern had a "must contain" character that was already found in the
1081        earlier partial match, unless partial matching was again requested. For
1082        example, with the pattern /dog.(body)?/, the "must contain" character is
1083        "g". If the first part-match was for the string "dog", restarting with
1084        "sbody" failed. This bug has been fixed.
1085    
1086    13. The string returned by pcre_dfa_exec() after a partial match has been
1087        changed so that it starts at the first inspected character rather than the
1088        first character of the match. This makes a difference only if the pattern
1089        starts with a lookbehind assertion or \b or \B (\K is not supported by
1090        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1091        matching functions compatible, and I think it's the right thing to do.
1092    
1093    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1094        so that the demonstration program is easily available in environments where
1095        PCRE has not been installed from source.
1096    
1097    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1098        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1099        library.
1100    
1101    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1102        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1103        is not the first non-POSIX option to be added. Clearly some people find
1104        these options useful.
1105    
1106    17. If a caller to the POSIX matching function regexec() passes a non-zero
1107        value for nmatch with a NULL value for pmatch, the value of
1108        nmatch is forced to zero.
1109    
1110    18. RunGrepTest did not have a test for the availability of the -u option of
1111        the diff command, as RunTest does. It now checks in the same way as
1112        RunTest, and also checks for the -b option.
1113    
1114    19. If an odd number of negated classes containing just a single character
1115        interposed, within parentheses, between a forward reference to a named
1116        subpattern and the definition of the subpattern, compilation crashed with
1117        an internal error, complaining that it could not find the referenced
1118        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1119        [The bug was that it was starting one character too far in when skipping
1120        over the character class, thus treating the ] as data rather than
1121        terminating the class. This meant it could skip too much.]
1122    
1123    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1124        /g option in pcretest when the pattern contains \K, which makes it possible
1125        to have an empty string match not at the start, even when the pattern is
1126        anchored. Updated pcretest and pcredemo to use this option.
1127    
1128    21. If the maximum number of capturing subpatterns in a recursion was greater
1129        than the maximum at the outer level, the higher number was returned, but
1130        with unset values at the outer level. The correct (outer level) value is
1131        now given.
1132    
1133    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1134        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1135        make it do so. The string so far is captured, making this feature
1136        compatible with Perl.
1137    
1138    23. The tests have been re-organized, adding tests 11 and 12, to make it
1139        possible to check the Perl 5.10 features against Perl 5.10.
1140    
1141    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1142        pattern matches a fixed length string. PCRE did not allow this; now it
1143        does. Neither allows recursion.
1144    
1145    25. I finally figured out how to implement a request to provide the minimum
1146        length of subject string that was needed in order to match a given pattern.
1147        (It was back references and recursion that I had previously got hung up
1148        on.) This code has now been added to pcre_study(); it finds a lower bound
1149        to the length of subject needed. It is not necessarily the greatest lower
1150        bound, but using it to avoid searching strings that are too short does give
1151        some useful speed-ups. The value is available to calling programs via
1152        pcre_fullinfo().
1153    
1154    26. While implementing 25, I discovered to my embarrassment that pcretest had
1155        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1156        study optimizations had never been tested with that matching function.
1157        Oops. What is worse, even when it was passed study data, there was a bug in
1158        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1159        were also very few tests of studied patterns with pcre_dfa_exec().
1160    
1161    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1162        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1163        on the other side of the coin, they are no longer allowed to have different
1164        names, because these cannot be distinguished in PCRE, and this has caused
1165        confusion. (This is a difference from Perl.)
1166    
1167    28. When duplicate subpattern names are present (necessarily with different
1168        numbers, as required by 27 above), and a test is made by name in a
1169        conditional pattern, either for a subpattern having been matched, or for
1170        recursion in such a pattern, all the associated numbered subpatterns are
1171        tested, and the overall condition is true if the condition is true for any
1172        one of them. This is the way Perl works, and is also more like the way
1173        testing by number works.
1174    
1175    
1176  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1177  ---------------------  ---------------------
1178    
# Line 112  Version 7.9 11-Apr-09 Line 1284  Version 7.9 11-Apr-09
1284    
1285  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
1286      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
1287    
1288  27. Wrapped the definitions of fileno and isatty for Windows, which appear in  27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1289      pcretest.c, inside #ifndefs, because it seems they are sometimes already      pcretest.c, inside #ifndefs, because it seems they are sometimes already
1290      pre-defined.      pre-defined.
1291    
1292  28. Added support for (*UTF8) at the start of a pattern.  28. Added support for (*UTF8) at the start of a pattern.
1293    
1294    29. Arrange for flags added by the "release type" setting in CMake to be shown
1295        in the configuration summary.
1296    
1297    
1298  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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