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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.5 12-Nov-07  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 the code for calculating the fixed length of lookbehind
11        assertions.
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    
34    Version 8.21 12-Dec-2011
35    ------------------------
36    
37    1.  Updating the JIT compiler.
38    
39    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
40        are added as well.
41    
42    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
43        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
44        calling _pcre_jit_exec. Some extra comments are added.
45    
46    4.  (*MARK) settings inside atomic groups that do not contain any capturing
47        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
48        was introduced by change 18 for 8.20.
49    
50    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
51        ECMA-262 standard.
52    
53    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
54        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
55        This bug was probably introduced by change 9 of 8.13.
56    
57    7.  While fixing 6 above, I noticed that a number of other items were being
58        incorrectly rejected as "not fixed length". This arose partly because newer
59        opcodes had not been added to the fixed-length checking code. I have (a)
60        corrected the bug and added tests for these items, and (b) arranged for an
61        error to occur if an unknown opcode is encountered while checking for fixed
62        length instead of just assuming "not fixed length". The items that were
63        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
64        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
65        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
66    
67    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
68        being incorrectly compiled and would have given unpredicatble results.
69    
70    9.  A possessively repeated subpattern with minimum repeat count greater than
71        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
72        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
73        the first (A) could occur when it should not.
74    
75    10. Add a cast and remove a redundant test from the code.
76    
77    11. JIT should use pcre_malloc/pcre_free for allocation.
78    
79    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
80        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
81        is anything other than /usr, -L is still shown).
82    
83    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
84    
85    14. Perl does not support \N without a following name in a [] class; PCRE now
86        also gives an error.
87    
88    15. If a forward reference was repeated with an upper limit of around 2000,
89        it caused the error "internal error: overran compiling workspace". The
90        maximum number of forward references (including repeats) was limited by the
91        internal workspace, and dependent on the LINK_SIZE. The code has been
92        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
93        the default depends on LINK_SIZE. There is a new upper limit (for safety)
94        of around 200,000 forward references. While doing this, I also speeded up
95        the filling in of repeated forward references.
96    
97    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
98        incorrectly expecting the subject to contain another "a" after the start.
99    
100    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
101        in the match, the SKIP should be ignored. This was not happening; instead
102        the SKIP was being treated as NOMATCH. For patterns such as
103        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
104        tested.
105    
106    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
107        now much more compatible with Perl, in particular in cases where the result
108        is a non-match for a non-anchored pattern. For example, if
109        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
110        "m", where previously it did not return a name. A side effect of this
111        change is that for partial matches, the last encountered mark name is
112        returned, as for non matches. A number of tests that were previously not
113        Perl-compatible have been moved into the Perl-compatible test files. The
114        refactoring has had the pleasing side effect of removing one argument from
115        the match() function, thus reducing its stack requirements.
116    
117    19. If the /S+ option was used in pcretest to study a pattern using JIT,
118        subsequent uses of /S (without +) incorrectly behaved like /S+.
119    
120    21. Retrieve executable code size support for the JIT compiler and fixing
121        some warnings.
122    
123    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
124        not work when the shorter character appeared right at the end of the
125        subject string.
126    
127    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
128        systems.
129    
130    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
131        output it when the /M option is used in pcretest.
132    
133    25. The CheckMan script was not being included in the distribution. Also, added
134        an explicit "perl" to run Perl scripts from the PrepareRelease script
135        because this is reportedly needed in Windows.
136    
137    26. If study data was being save in a file and studying had not found a set of
138        "starts with" bytes for the pattern, the data written to the file (though
139        never used) was taken from uninitialized memory and so caused valgrind to
140        complain.
141    
142    27. Updated RunTest.bat as provided by Sheri Pierce.
143    
144    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
145    
146    29. Computation of memory usage for the table of capturing group names was
147        giving an unnecessarily large value.
148    
149    
150    Version 8.20 21-Oct-2011
151    ------------------------
152    
153    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
154        a POSIX class. After further experiments with Perl, which convinced me that
155        Perl has bugs and confusions, a closing square bracket is no longer allowed
156        in a POSIX name. This bug also affected patterns with classes that started
157        with full stops.
158    
159    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
160        captured substring, but while checking the failing first alternative,
161        substring 1 is temporarily captured. If the output vector supplied to
162        pcre_exec() was not big enough for this capture, the yield of the function
163        was still zero ("insufficient space for captured substrings"). This cannot
164        be totally fixed without adding another stack variable, which seems a lot
165        of expense for a edge case. However, I have improved the situation in cases
166        such as /(a)(b)x|abc/ matched against "abc", where the return code
167        indicates that fewer than the maximum number of slots in the ovector have
168        been set.
169    
170    3.  Related to (2) above: when there are more back references in a pattern than
171        slots in the output vector, pcre_exec() uses temporary memory during
172        matching, and copies in the captures as far as possible afterwards. It was
173        using the entire output vector, but this conflicts with the specification
174        that only 2/3 is used for passing back captured substrings. Now it uses
175        only the first 2/3, for compatibility. This is, of course, another edge
176        case.
177    
178    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
179        main code base, and can be used by building with --enable-jit. When this is
180        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
181        runtime --no-jit option is given.
182    
183    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
184        ovector, the return from the function was zero, implying that there were
185        other matches that did not fit. The correct "exactly full" value is now
186        returned.
187    
188    6.  If a subpattern that was called recursively or as a subroutine contained
189        (*PRUNE) or any other control that caused it to give a non-standard return,
190        invalid errors such as "Error -26 (nested recursion at the same subject
191        position)" or even infinite loops could occur.
192    
193    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
194        computing the minimum length on reaching *ACCEPT, and so ended up with the
195        wrong value of 1 rather than 0. Further investigation indicates that
196        computing a minimum subject length in the presence of *ACCEPT is difficult
197        (think back references, subroutine calls), and so I have changed the code
198        so that no minimum is registered for a pattern that contains *ACCEPT.
199    
200    8.  If (*THEN) was present in the first (true) branch of a conditional group,
201        it was not handled as intended. [But see 16 below.]
202    
203    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
204        Sheri Pierce.
205    
206    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
207        the first byte in a match must be "a".
208    
209    11. Change 17 for 8.13 increased the recursion depth for patterns like
210        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
211        pattern contains any instances of (*THEN). If it does not, the old
212        optimizations are restored. It would be nice to do this on a per-group
213        basis, but at the moment that is not feasible.
214    
215    12. In some environments, the output of pcretest -C is CRLF terminated. This
216        broke RunTest's code that checks for the link size. A single white space
217        character after the value is now allowed for.
218    
219    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
220        For "fr", it uses the Windows-specific input and output files.
221    
222    14. If (*THEN) appeared in a group that was called recursively or as a
223        subroutine, it did not work as intended. [But see next item.]
224    
225    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
226        pattern fragments (but not containing any | characters). If A and B are
227        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
228        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
229        D. In other words, Perl considers parentheses that do not contain any |
230        characters to be part of a surrounding alternative, whereas PCRE was
231        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
232        differently. PCRE now behaves in the same way as Perl, except in the case
233        of subroutine/recursion calls such as (?1) which have in any case always
234        been different (but PCRE had them first :-).
235    
236    16. Related to 15 above: Perl does not treat the | in a conditional group as
237        creating alternatives. Such a group is treated in the same way as an
238        ordinary group without any | characters when processing (*THEN). PCRE has
239        been changed to match Perl's behaviour.
240    
241    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
242        RunGrepTest script failed.
243    
244    18. Change 22 for version 13 caused atomic groups to use more stack. This is
245        inevitable for groups that contain captures, but it can lead to a lot of
246        stack use in large patterns. The old behaviour has been restored for atomic
247        groups that do not contain any capturing parentheses.
248    
249    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
250        suppress the check for a minimum subject length at run time. (If it was
251        given to pcre_exec() or pcre_dfa_exec() it did work.)
252    
253    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
254        fail to work when decoding hex characters in data strings in EBCDIC
255        environments.
256    
257    21. It appears that in at least one Mac OS environment, the isxdigit() function
258        is implemented as a macro that evaluates to its argument more than once,
259        contravening the C 90 Standard (I haven't checked a later standard). There
260        was an instance in pcretest which caused it to go wrong when processing
261        \x{...} escapes in subject strings. The has been rewritten to avoid using
262        things like p++ in the argument of isxdigit().
263    
264    
265    Version 8.13 16-Aug-2011
266    ------------------------
267    
268    1.  The Unicode data tables have been updated to Unicode 6.0.0.
269    
270    2.  Two minor typos in pcre_internal.h have been fixed.
271    
272    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
273        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
274        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
275    
276    4.  There were a number of related bugs in the code for matching backrefences
277        caselessly in UTF-8 mode when codes for the characters concerned were
278        different numbers of bytes. For example, U+023A and U+2C65 are an upper
279        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
280        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
281        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
282        2-byte code at the end of the subject (it thought there wasn't enough data
283        left).
284    
285    5.  Comprehensive information about what went wrong is now returned by
286        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
287        as the output vector has at least 2 elements. The offset of the start of
288        the failing character and a reason code are placed in the vector.
289    
290    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
291        now returned is for the first byte of the failing character, instead of the
292        last byte inspected. This is an incompatible change, but I hope it is small
293        enough not to be a problem. It makes the returned offset consistent with
294        pcre_exec() and pcre_dfa_exec().
295    
296    7.  pcretest now gives a text phrase as well as the error number when
297        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
298        failure, the offset and reason code are output.
299    
300    8.  When \R was used with a maximizing quantifier it failed to skip backwards
301        over a \r\n pair if the subsequent match failed. Instead, it just skipped
302        back over a single character (\n). This seems wrong (because it treated the
303        two characters as a single entity when going forwards), conflicts with the
304        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
305        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
306        has been changed.
307    
308    9.  Some internal refactoring has changed the processing so that the handling
309        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
310        time (the PCRE_DOTALL option was changed this way some time ago: version
311        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
312        which was always a bit of a fudge. It also means that there is one less
313        argument for the match() function, which reduces its stack requirements
314        slightly. This change also fixes an incompatibility with Perl: the pattern
315        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
316    
317    10. More internal refactoring has drastically reduced the number of recursive
318        calls to match() for possessively repeated groups such as (abc)++ when
319        using pcre_exec().
320    
321    11. While implementing 10, a number of bugs in the handling of groups were
322        discovered and fixed:
323    
324        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
325        (a|)*(?1) gave a compile-time internal error.
326        ((a|)+)+  did not notice that the outer group could match an empty string.
327        (^a|^)+   was not marked as anchored.
328        (.*a|.*)+ was not marked as matching at start or after a newline.
329    
330    12. Yet more internal refactoring has removed another argument from the match()
331        function. Special calls to this function are now indicated by setting a
332        value in a variable in the "match data" data block.
333    
334    13. Be more explicit in pcre_study() instead of relying on "default" for
335        opcodes that mean there is no starting character; this means that when new
336        ones are added and accidentally left out of pcre_study(), testing should
337        pick them up.
338    
339    14. The -s option of pcretest has been documented for ages as being an old
340        synonym of -m (show memory usage). I have changed it to mean "force study
341        for every regex", that is, assume /S for every regex. This is similar to -i
342        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
343        using it. It makes it easier to run collections of tests with and without
344        study enabled, and thereby test pcre_study() more easily. All the standard
345        tests are now run with and without -s (but some patterns can be marked as
346        "never study" - see 20 below).
347    
348    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
349        restoration of the capturing data to the outer values was not happening
350        correctly.
351    
352    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
353        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
354        pattern had matched an empty string, and so incorrectly returned a no
355        match.
356    
357    17. There was optimizing code for the last branch of non-capturing parentheses,
358        and also for the obeyed branch of a conditional subexpression, which used
359        tail recursion to cut down on stack usage. Unfortunately, now that there is
360        the possibility of (*THEN) occurring in these branches, tail recursion is
361        no longer possible because the return has to be checked for (*THEN). These
362        two optimizations have therefore been removed. [But see 8.20/11 above.]
363    
364    18. If a pattern containing \R was studied, it was assumed that \R always
365        matched two bytes, thus causing the minimum subject length to be
366        incorrectly computed because \R can also match just one byte.
367    
368    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
369        was incorrectly computed.
370    
371    20. If /S is present twice on a test pattern in pcretest input, it now
372        *disables* studying, thereby overriding the use of -s on the command line
373        (see 14 above). This is necessary for one or two tests to keep the output
374        identical in both cases.
375    
376    21. When (*ACCEPT) was used in an assertion that matched an empty string and
377        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
378    
379    22. When an atomic group that contained a capturing parenthesis was
380        successfully matched, but the branch in which it appeared failed, the
381        capturing was not being forgotten if a higher numbered group was later
382        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
383        group 1 to "a", when in fact it should be unset. This applied to multi-
384        branched capturing and non-capturing groups, repeated or not, and also to
385        positive assertions (capturing in negative assertions does not happen
386        in PCRE) and also to nested atomic groups.
387    
388    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
389        subject after a captured substring, to make it easier to tell which of a
390        number of identical substrings has been captured.
391    
392    24. The way atomic groups are processed by pcre_exec() has been changed so that
393        if they are repeated, backtracking one repetition now resets captured
394        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
395        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
396        "aaa". Previously, it would have been "a". As part of this code
397        refactoring, the way recursive calls are handled has also been changed.
398    
399    25. If an assertion condition captured any substrings, they were not passed
400        back unless some other capturing happened later. For example, if
401        (?(?=(a))a) was matched against "a", no capturing was returned.
402    
403    26. When studying a pattern that contained subroutine calls or assertions,
404        the code for finding the minimum length of a possible match was handling
405        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
406        group 1 called group 2 while simultaneously a separate group 2 called group
407        1). A stack overflow occurred in this case. I have fixed this by limiting
408        the recursion depth to 10.
409    
410    27. Updated RunTest.bat in the distribution to the version supplied by Tom
411        Fortmann. This supports explicit test numbers on the command line, and has
412        argument validation and error reporting.
413    
414    28. An instance of \X with an unlimited repeat could fail if at any point the
415        first character it looked at was a mark character.
416    
417    29. Some minor code refactoring concerning Unicode properties and scripts
418        should reduce the stack requirement of match() slightly.
419    
420    30. Added the '=' option to pcretest to check the setting of unused capturing
421        slots at the end of the pattern, which are documented as being -1, but are
422        not included in the return count.
423    
424    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
425        compiled something random. Now it gives a compile-time error (as does
426        Perl).
427    
428    32. A *MARK encountered during the processing of a positive assertion is now
429        recorded and passed back (compatible with Perl).
430    
431    33. If --only-matching or --colour was set on a pcregrep call whose pattern
432        had alternative anchored branches, the search for a second match in a line
433        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
434        matched the line "0102" twice. The same bug affected patterns that started
435        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
436        twice.
437    
438    34. Previously, PCRE did not allow quantification of assertions. However, Perl
439        does, and because of capturing effects, quantifying parenthesized
440        assertions may at times be useful. Quantifiers are now allowed for
441        parenthesized assertions.
442    
443    35. A minor code tidy in pcre_compile() when checking options for \R usage.
444    
445    36. \g was being checked for fancy things in a character class, when it should
446        just be a literal "g".
447    
448    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
449        appearance of a nested POSIX class supersedes an apparent external class.
450        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
451        unescaped square brackets may also appear as part of class names. For
452        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
453        more like Perl. (But see 8.20/1 above.)
454    
455    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
456        was because it thought it was \N{name}, which is not supported).
457    
458    39. Add minix to OS list not supporting the -S option in pcretest.
459    
460    40. PCRE tries to detect cases of infinite recursion at compile time, but it
461        cannot analyze patterns in sufficient detail to catch mutual recursions
462        such as ((?1))((?2)). There is now a runtime test that gives an error if a
463        subgroup is called recursively as a subpattern for a second time at the
464        same position in the subject string. In previous releases this might have
465        been caught by the recursion limit, or it might have run out of stack.
466    
467    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
468        happen only once. PCRE was, however incorrectly giving a compile time error
469        "recursive call could loop indefinitely" because it cannot analyze the
470        pattern in sufficient detail. The compile time test no longer happens when
471        PCRE is compiling a conditional subpattern, but actual runaway loops are
472        now caught at runtime (see 40 above).
473    
474    42. It seems that Perl allows any characters other than a closing parenthesis
475        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
476        has been changed to be the same.
477    
478    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
479        as not to get warnings when autogen.sh is called. Also changed
480        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
481    
482    44. To help people who use pcregrep to scan files containing exceedingly long
483        lines, the following changes have been made:
484    
485        (a) The default value of the buffer size parameter has been increased from
486            8K to 20K. (The actual buffer used is three times this size.)
487    
488        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
489            PCRE is built.
490    
491        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
492            to be set at run time.
493    
494        (d) Numerical values in pcregrep options can be followed by K or M, for
495            example --buffer-size=50K.
496    
497        (e) If a line being scanned overflows pcregrep's buffer, an error is now
498            given and the return code is set to 2.
499    
500    45. Add a pointer to the latest mark to the callout data block.
501    
502    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
503        partial match of an empty string instead of no match. This was specific to
504        the use of ".".
505    
506    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
507        complete match instead of a partial match. This bug was dependent on both
508        the PCRE_UTF8 and PCRE_DOTALL options being set.
509    
510    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
511        starting byte set, because \b was not being ignored.
512    
513    
514    Version 8.12 15-Jan-2011
515    ------------------------
516    
517    1.  Fixed some typos in the markup of the man pages, and wrote a script that
518        checks for such things as part of the documentation building process.
519    
520    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
521        --match-limit and --recursion-limit options (added for 8.11). In
522        particular, this made one of the standard tests fail. (The integer value
523        went into the wrong half of a long int.)
524    
525    3.  If the --colour option was given to pcregrep with -v (invert match), it
526        did strange things, either producing crazy output, or crashing. It should,
527        of course, ignore a request for colour when reporting lines that do not
528        match.
529    
530    4.  Another pcregrep bug caused similar problems if --colour was specified with
531        -M (multiline) and the pattern match finished with a line ending.
532    
533    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
534        matched in multiline mode, the following line was shown as part of the
535        match. This seems wrong, so I have changed it.
536    
537    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
538        the check for further matches in the same line (so they could be coloured)
539        to overrun the end of the current line. If another match was found, it was
540        incorrectly shown (and then shown again when found in the next line).
541    
542    7.  If pcregrep was compiled under Windows, there was a reference to the
543        function pcregrep_exit() before it was defined. I am assuming this was
544        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
545        reported by a user. I've moved the definition above the reference.
546    
547    
548    Version 8.11 10-Dec-2010
549    ------------------------
550    
551    1.  (*THEN) was not working properly if there were untried alternatives prior
552        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
553        backtracked to try for "b" instead of moving to the next alternative branch
554        at the same level (in this case, to look for "c"). The Perl documentation
555        is clear that when (*THEN) is backtracked onto, it goes to the "next
556        alternative in the innermost enclosing group".
557    
558    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
559        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
560        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
561        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
562        (*THEN).
563    
564    3.  If \s appeared in a character class, it removed the VT character from
565        the class, even if it had been included by some previous item, for example
566        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
567        of \s, but is part of the POSIX "space" class.)
568    
569    4.  A partial match never returns an empty string (because you can always
570        match an empty string at the end of the subject); however the checking for
571        an empty string was starting at the "start of match" point. This has been
572        changed to the "earliest inspected character" point, because the returned
573        data for a partial match starts at this character. This means that, for
574        example, /(?<=abc)def/ gives a partial match for the subject "abc"
575        (previously it gave "no match").
576    
577    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
578        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
579        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
580        has an implication that the given string is incomplete (because a partial
581        match is preferred over a full match). For this reason, these items now
582        give a partial match in this situation. [Aside: previously, the one case
583        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
584        match rather than a full match, which was wrong by the old rules, but is
585        now correct.]
586    
587    6.  There was a bug in the handling of #-introduced comments, recognized when
588        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
589        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
590        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
591        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
592        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
593        places in pcre_compile().
594    
595    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
596        comments when looking ahead for named forward references to subpatterns,
597        the only newline sequence it recognized was NL. It now handles newlines
598        according to the set newline convention.
599    
600    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
601        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
602        cater for a lack of strerror(). These oversights have been fixed.
603    
604    9.  Added --match-limit and --recursion-limit to pcregrep.
605    
606    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
607    
608    11. When the -o option was used, pcregrep was setting a return code of 1, even
609        when matches were found, and --line-buffered was not being honoured.
610    
611    12. Added an optional parentheses number to the -o and --only-matching options
612        of pcregrep.
613    
614    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
615        can match an empty string. The code to do it in pcretest and pcredemo
616        needed fixing:
617    
618        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
619            only one byte after an empty string match just before CRLF (this case
620            just got forgotten; "any" and "anycrlf" were OK).
621    
622        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
623            mode when an empty string match preceded an ASCII character followed by
624            a non-ASCII character. (The code for advancing by one character rather
625            than one byte was nonsense.)
626    
627        (c) The pcredemo.c sample program did not have any code at all to handle
628            the cases when CRLF is a valid newline sequence.
629    
630    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
631        as a starting offset was within the subject string. There is now a new
632        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
633        negative or greater than the length of the string. In order to test this,
634        pcretest is extended to allow the setting of negative starting offsets.
635    
636    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
637        starting offset points to the beginning of a UTF-8 character was
638        unnecessarily clumsy. I tidied it up.
639    
640    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
641        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
642    
643    17. Nobody had reported that the --include_dir option, which was added in
644        release 7.7 should have been called --include-dir (hyphen, not underscore)
645        for compatibility with GNU grep. I have changed it to --include-dir, but
646        left --include_dir as an undocumented synonym, and the same for
647        --exclude-dir, though that is not available in GNU grep, at least as of
648        release 2.5.4.
649    
650    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
651        characters from a string of bytes) have been redefined so as not to use
652        loops, in order to improve performance in some environments. At the same
653        time, I abstracted some of the common code into auxiliary macros to save
654        repetition (this should not affect the compiled code).
655    
656    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
657        compile-time error is now given if \c is not followed by an ASCII
658        character, that is, a byte less than 128. (In EBCDIC mode, the code is
659        different, and any byte value is allowed.)
660    
661    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
662        START_OPTIMIZE option, which is now allowed at compile time - but just
663        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
664        to pcregrep and other applications that have no direct access to PCRE
665        options. The new /Y option in pcretest sets this option when calling
666        pcre_compile().
667    
668    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
669        back references. Groups containing recursive back references were forced to
670        be atomic by that change, but in the case of named groups, the amount of
671        memory required was incorrectly computed, leading to "Failed: internal
672        error: code overflow". This has been fixed.
673    
674    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
675        pcretest.c, to avoid build problems in some Borland environments.
676    
677    
678    Version 8.10 25-Jun-2010
679    ------------------------
680    
681    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
682        THEN.
683    
684    2.  (*ACCEPT) was not working when inside an atomic group.
685    
686    3.  Inside a character class, \B is treated as a literal by default, but
687        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
688        causes the error). The code is unchanged, but I tidied the documentation.
689    
690    4.  Inside a character class, PCRE always treated \R and \X as literals,
691        whereas Perl faults them if its -w option is set. I have changed PCRE so
692        that it faults them when PCRE_EXTRA is set.
693    
694    5.  Added support for \N, which always matches any character other than
695        newline. (It is the same as "." when PCRE_DOTALL is not set.)
696    
697    6.  When compiling pcregrep with newer versions of gcc which may have
698        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
699        declared with attribute warn_unused_result" were given. Just casting the
700        result to (void) does not stop the warnings; a more elaborate fudge is
701        needed. I've used a macro to implement this.
702    
703    7.  Minor change to pcretest.c to avoid a compiler warning.
704    
705    8.  Added four artifical Unicode properties to help with an option to make
706        \s etc use properties (see next item). The new properties are: Xan
707        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
708    
709    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
710        use Unicode properties. (*UCP) at the start of a pattern can be used to set
711        this option. Modified pcretest to add /W to test this facility. Added
712        REG_UCP to make it available via the POSIX interface.
713    
714    10. Added --line-buffered to pcregrep.
715    
716    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
717        studied, and the match started with a letter with a code point greater than
718        127 whose first byte was different to the first byte of the other case of
719        the letter, the other case of this starting letter was not recognized
720        (#976).
721    
722    12. If a pattern that was studied started with a repeated Unicode property
723        test, for example, \p{Nd}+, there was the theoretical possibility of
724        setting up an incorrect bitmap of starting bytes, but fortunately it could
725        not have actually happened in practice until change 8 above was made (it
726        added property types that matched character-matching opcodes).
727    
728    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
729        possible starting bytes for non-anchored patterns.
730    
731    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
732        \R, and also a number of cases that involve Unicode properties, both
733        explicit and implicit when PCRE_UCP is set.
734    
735    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
736        input, it could crash or give wrong results if characters with values
737        greater than 0xc0 were present in the subject string. (Detail: it assumed
738        UTF-8 input when processing these items.)
739    
740    16. Added a lot of (int) casts to avoid compiler warnings in systems where
741        size_t is 64-bit (#991).
742    
743    17. Added a check for running out of memory when PCRE is compiled with
744        --disable-stack-for-recursion (#990).
745    
746    18. If the last data line in a file for pcretest does not have a newline on
747        the end, a newline was missing in the output.
748    
749    19. The default pcre_chartables.c file recognizes only ASCII characters (values
750        less than 128) in its various bitmaps. However, there is a facility for
751        generating tables according to the current locale when PCRE is compiled. It
752        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
753        characters, are recognized by isspace() and therefore were getting set in
754        these tables, and indeed these tables seem to approximate to ISO 8859. This
755        caused a problem in UTF-8 mode when pcre_study() was used to create a list
756        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
757        which of course cannot start UTF-8 characters. I have changed the code so
758        that only real ASCII characters (less than 128) and the correct starting
759        bytes for UTF-8 encodings are set for characters greater than 127 when in
760        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
761        altogether.)
762    
763    20. Added the /T option to pcretest so as to be able to run tests with non-
764        standard character tables, thus making it possible to include the tests
765        used for 19 above in the standard set of tests.
766    
767    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
768        reference to a subpattern the other side of a comment that contains an
769        opening parenthesis caused either an internal compiling error, or a
770        reference to the wrong subpattern.
771    
772    
773    Version 8.02 19-Mar-2010
774    ------------------------
775    
776    1.  The Unicode data tables have been updated to Unicode 5.2.0.
777    
778    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
779        configured.
780    
781    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
782        original author of that file, following a query about its status.
783    
784    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
785        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
786    
787    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
788        quantifier applied to a forward-referencing subroutine call, could compile
789        incorrect code or give the error "internal error: previously-checked
790        referenced subpattern not found".
791    
792    6.  Both MS Visual Studio and Symbian OS have problems with initializing
793        variables to point to external functions. For these systems, therefore,
794        pcre_malloc etc. are now initialized to local functions that call the
795        relevant global functions.
796    
797    7.  There were two entries missing in the vectors called coptable and poptable
798        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
799        I've fixed the data, and added a kludgy way of testing at compile time that
800        the lengths are correct (equal to the number of opcodes).
801    
802    8.  Following on from 7, I added a similar kludge to check the length of the
803        eint vector in pcreposix.c.
804    
805    9.  Error texts for pcre_compile() are held as one long string to avoid too
806        much relocation at load time. To find a text, the string is searched,
807        counting zeros. There was no check for running off the end of the string,
808        which could happen if a new error number was added without updating the
809        string.
810    
811    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
812    
813    11. \K was not working if it appeared in an atomic group or in a group that
814        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
815        \K is "not well defined" if used in an assertion. PCRE now accepts it if
816        the assertion is positive, but not if it is negative.
817    
818    12. Change 11 fortuitously reduced the size of the stack frame used in the
819        "match()" function of pcre_exec.c by one pointer. Forthcoming
820        implementation of support for (*MARK) will need an extra pointer on the
821        stack; I have reserved it now, so that the stack frame size does not
822        decrease.
823    
824    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
825        item in branch that calls a recursion is a subroutine call - as in the
826        second branch in the above example - was incorrectly given the compile-
827        time error "recursive call could loop indefinitely" because pcre_compile()
828        was not correctly checking the subroutine for matching a non-empty string.
829    
830    14. The checks for overrunning compiling workspace could trigger after an
831        overrun had occurred. This is a "should never occur" error, but it can be
832        triggered by pathological patterns such as hundreds of nested parentheses.
833        The checks now trigger 100 bytes before the end of the workspace.
834    
835    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
836    
837    
838    Version 8.01 19-Jan-2010
839    ------------------------
840    
841    1.  If a pattern contained a conditional subpattern with only one branch (in
842        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
843        computed the wrong minimum data length (which is of course zero for such
844        subpatterns). This could cause incorrect "no match" results.
845    
846    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
847        the pattern is reset in the first branch, pcre_compile() failed with
848        "internal error: code overflow at offset...". This happened only when
849        the reset was to the original external option setting. (An optimization
850        abstracts leading options settings into an external setting, which was the
851        cause of this.)
852    
853    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
854        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
855        assertion pattern did not match (meaning that the assertion was true), it
856        was incorrectly treated as false if the SKIP had been reached during the
857        matching. This also applied to assertions used as conditions.
858    
859    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
860        assertion subpattern, including such a pattern used as a condition,
861        unpredictable results occurred, instead of the error return
862        PCRE_ERROR_DFA_UITEM.
863    
864    5.  The C++ GlobalReplace function was not working like Perl for the special
865        situation when an empty string is matched. It now does the fancy magic
866        stuff that is necessary.
867    
868    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
869        removed. (These were left over from very, very early versions of PCRE.)
870    
871    7.  Some cosmetic changes to the code to make life easier when compiling it
872        as part of something else:
873    
874        (a) Change DEBUG to PCRE_DEBUG.
875    
876        (b) In pcre_compile(), rename the member of the "branch_chain" structure
877            called "current" as "current_branch", to prevent a collision with the
878            Linux macro when compiled as a kernel module.
879    
880        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
881            prevent a collision with the Linux macro when compiled as a kernel
882            module.
883    
884    8.  In pcre_compile() there are some checks for integer overflows that used to
885        cast potentially large values to (double). This has been changed to that
886        when building, a check for int64_t is made, and if it is found, it is used
887        instead, thus avoiding the use of floating point arithmetic. (There is no
888        other use of FP in PCRE.) If int64_t is not found, the fallback is to
889        double.
890    
891    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
892        2005 (difference between two addresses compared to an unsigned value).
893    
894    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
895        custom one, because of the following reported problem in Windows:
896    
897          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
898              under Win32.
899          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
900              therefore missing the function definition.
901          - The compiler thus generates a "C" signature for the test function.
902          - The linker fails to find the "C" function.
903          - PCRE fails to configure if asked to do so against libbz2.
904    
905    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
906        messages were output:
907    
908          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
909          rerunning libtoolize, to keep the correct libtool macros in-tree.
910          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
911    
912        I have done both of these things.
913    
914    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
915        most of the time, it *can* run out if it is given a pattern that contains a
916        runaway infinite recursion. I updated the discussion in the pcrestack man
917        page.
918    
919    13. Now that we have gone to the x.xx style of version numbers, the minor
920        version may start with zero. Using 08 or 09 is a bad idea because users
921        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
922        interpreted as invalid octal numbers. I've updated the previous comment in
923        configure.ac, and also added a check that gives an error if 08 or 09 are
924        used.
925    
926    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
927        causing partial matching to fail when the end of the subject matched \W
928        in a UTF-8 pattern where \W was quantified with a minimum of 3.
929    
930    15. There were some discrepancies between the declarations in pcre_internal.h
931        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
932        their definitions. The declarations used "const uschar *" and the
933        definitions used USPTR. Even though USPTR is normally defined as "const
934        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
935        reported that: "This difference in casting confuses some C++ compilers, for
936        example, SunCC recognizes above declarations as different functions and
937        generates broken code for hbpcre." I have changed the declarations to use
938        USPTR.
939    
940    16. GNU libtool is named differently on some systems. The autogen.sh script now
941        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
942        (FreeBSD).
943    
944    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
945        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
946        comment: "Figure out how to create a longlong from a string: strtoll and
947        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
948        instance, but it only takes 2 args instead of 3!"
949    
950    18. A subtle bug concerned with back references has been fixed by a change of
951        specification, with a corresponding code fix. A pattern such as
952        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
953        refers, was giving matches when it shouldn't. For example, xa=xaaa would
954        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
955        same bug. Such groups have to be quantified to be useful, or contained
956        inside another quantified group. (If there's no repetition, the reference
957        can never match.) The problem arises because, having left the group and
958        moved on to the rest of the pattern, a later failure that backtracks into
959        the group uses the captured value from the final iteration of the group
960        rather than the correct earlier one. I have fixed this in PCRE by forcing
961        any group that contains a reference to itself to be an atomic group; that
962        is, there cannot be any backtracking into it once it has completed. This is
963        similar to recursive and subroutine calls.
964    
965    
966    Version 8.00 19-Oct-09
967    ----------------------
968    
969    1.  The table for translating pcre_compile() error codes into POSIX error codes
970        was out-of-date, and there was no check on the pcre_compile() error code
971        being within the table. This could lead to an OK return being given in
972        error.
973    
974    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
975        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
976        in a Windows environment.
977    
978    3.  The pcregrep --count option prints the count for each file even when it is
979        zero, as does GNU grep. However, pcregrep was also printing all files when
980        --files-with-matches was added. Now, when both options are given, it prints
981        counts only for those files that have at least one match. (GNU grep just
982        prints the file name in this circumstance, but including the count seems
983        more useful - otherwise, why use --count?) Also ensured that the
984        combination -clh just lists non-zero counts, with no names.
985    
986    4.  The long form of the pcregrep -F option was incorrectly implemented as
987        --fixed_strings instead of --fixed-strings. This is an incompatible change,
988        but it seems right to fix it, and I didn't think it was worth preserving
989        the old behaviour.
990    
991    5.  The command line items --regex=pattern and --regexp=pattern were not
992        recognized by pcregrep, which required --regex pattern or --regexp pattern
993        (with a space rather than an '='). The man page documented the '=' forms,
994        which are compatible with GNU grep; these now work.
995    
996    6.  No libpcreposix.pc file was created for pkg-config; there was just
997        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
998    
999    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1000        when UCP support is not needed, by modifying the Python script that
1001        generates it from Unicode data files. This should not matter if the module
1002        is correctly used as a library, but I received one complaint about 50K of
1003        unwanted data. My guess is that the person linked everything into his
1004        program rather than using a library. Anyway, it does no harm.
1005    
1006    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1007        was a minimum greater than 1 for a wide character in a possessive
1008        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1009        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1010        character. Chaos in the form of incorrect output or a compiling loop could
1011        result.
1012    
1013    9.  The restrictions on what a pattern can contain when partial matching is
1014        requested for pcre_exec() have been removed. All patterns can now be
1015        partially matched by this function. In addition, if there are at least two
1016        slots in the offset vector, the offset of the earliest inspected character
1017        for the match and the offset of the end of the subject are set in them when
1018        PCRE_ERROR_PARTIAL is returned.
1019    
1020    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1021        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1022        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1023        and may be more useful for multi-segment matching.
1024    
1025    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1026        used to be given if ever the end of the subject was reached; now it is
1027        given only if matching could not proceed because another character was
1028        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1029        string "Z", which now yields "no match" instead of "partial match". In the
1030        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1031        final character ended with (*FAIL).
1032    
1033    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1034        if the pattern had a "must contain" character that was already found in the
1035        earlier partial match, unless partial matching was again requested. For
1036        example, with the pattern /dog.(body)?/, the "must contain" character is
1037        "g". If the first part-match was for the string "dog", restarting with
1038        "sbody" failed. This bug has been fixed.
1039    
1040    13. The string returned by pcre_dfa_exec() after a partial match has been
1041        changed so that it starts at the first inspected character rather than the
1042        first character of the match. This makes a difference only if the pattern
1043        starts with a lookbehind assertion or \b or \B (\K is not supported by
1044        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1045        matching functions compatible, and I think it's the right thing to do.
1046    
1047    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1048        so that the demonstration program is easily available in environments where
1049        PCRE has not been installed from source.
1050    
1051    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1052        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1053        library.
1054    
1055    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1056        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1057        is not the first non-POSIX option to be added. Clearly some people find
1058        these options useful.
1059    
1060    17. If a caller to the POSIX matching function regexec() passes a non-zero
1061        value for nmatch with a NULL value for pmatch, the value of
1062        nmatch is forced to zero.
1063    
1064    18. RunGrepTest did not have a test for the availability of the -u option of
1065        the diff command, as RunTest does. It now checks in the same way as
1066        RunTest, and also checks for the -b option.
1067    
1068    19. If an odd number of negated classes containing just a single character
1069        interposed, within parentheses, between a forward reference to a named
1070        subpattern and the definition of the subpattern, compilation crashed with
1071        an internal error, complaining that it could not find the referenced
1072        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1073        [The bug was that it was starting one character too far in when skipping
1074        over the character class, thus treating the ] as data rather than
1075        terminating the class. This meant it could skip too much.]
1076    
1077    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1078        /g option in pcretest when the pattern contains \K, which makes it possible
1079        to have an empty string match not at the start, even when the pattern is
1080        anchored. Updated pcretest and pcredemo to use this option.
1081    
1082    21. If the maximum number of capturing subpatterns in a recursion was greater
1083        than the maximum at the outer level, the higher number was returned, but
1084        with unset values at the outer level. The correct (outer level) value is
1085        now given.
1086    
1087    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1088        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1089        make it do so. The string so far is captured, making this feature
1090        compatible with Perl.
1091    
1092    23. The tests have been re-organized, adding tests 11 and 12, to make it
1093        possible to check the Perl 5.10 features against Perl 5.10.
1094    
1095    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1096        pattern matches a fixed length string. PCRE did not allow this; now it
1097        does. Neither allows recursion.
1098    
1099    25. I finally figured out how to implement a request to provide the minimum
1100        length of subject string that was needed in order to match a given pattern.
1101        (It was back references and recursion that I had previously got hung up
1102        on.) This code has now been added to pcre_study(); it finds a lower bound
1103        to the length of subject needed. It is not necessarily the greatest lower
1104        bound, but using it to avoid searching strings that are too short does give
1105        some useful speed-ups. The value is available to calling programs via
1106        pcre_fullinfo().
1107    
1108    26. While implementing 25, I discovered to my embarrassment that pcretest had
1109        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1110        study optimizations had never been tested with that matching function.
1111        Oops. What is worse, even when it was passed study data, there was a bug in
1112        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1113        were also very few tests of studied patterns with pcre_dfa_exec().
1114    
1115    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1116        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1117        on the other side of the coin, they are no longer allowed to have different
1118        names, because these cannot be distinguished in PCRE, and this has caused
1119        confusion. (This is a difference from Perl.)
1120    
1121    28. When duplicate subpattern names are present (necessarily with different
1122        numbers, as required by 27 above), and a test is made by name in a
1123        conditional pattern, either for a subpattern having been matched, or for
1124        recursion in such a pattern, all the associated numbered subpatterns are
1125        tested, and the overall condition is true if the condition is true for any
1126        one of them. This is the way Perl works, and is also more like the way
1127        testing by number works.
1128    
1129    
1130    Version 7.9 11-Apr-09
1131    ---------------------
1132    
1133    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1134        (pcretest), all targets were linked against these libraries. This included
1135        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1136        libraries. This caused unwanted dependencies to be created. This problem
1137        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1138        pcretest is linked with readline.
1139    
1140    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1141        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1142        moved outside it again, because FALSE and TRUE are already defined in AIX,
1143        but BOOL is not.
1144    
1145    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1146        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1147    
1148    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1149        hyphens) following file names and line numbers when outputting matching
1150        lines. This is not true; no spaces are inserted. I have also clarified the
1151        wording for the --colour (or --color) option.
1152    
1153    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1154        was not coloured; this is different to GNU grep, so I have changed it to be
1155        the same.
1156    
1157    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1158        each matching line was coloured. Now it goes on to look for further matches
1159        of any of the test patterns, which is the same behaviour as GNU grep.
1160    
1161    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1162        doesn't make sense to accept an empty string match in pcregrep, so I have
1163        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1164        seems to be how GNU grep behaves.
1165    
1166    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1167        start or after a newline", because the conditional assertion was not being
1168        correctly handled. The rule now is that both the assertion and what follows
1169        in the first alternative must satisfy the test.
1170    
1171    9.  If auto-callout was enabled in a pattern with a conditional group whose
1172        condition was an assertion, PCRE could crash during matching, both with
1173        pcre_exec() and pcre_dfa_exec().
1174    
1175    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1176        used for matching.
1177    
1178    11. Unicode property support in character classes was not working for
1179        characters (bytes) greater than 127 when not in UTF-8 mode.
1180    
1181    12. Added the -M command line option to pcretest.
1182    
1183    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1184    
1185    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1186    
1187    16. Added comments and documentation about mis-use of no_arg in the C++
1188        wrapper.
1189    
1190    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1191        from Martin Jerabek that uses macro names for all relevant character and
1192        string constants.
1193    
1194    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1195        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1196        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1197        these, but not everybody uses configure.
1198    
1199    19. A conditional group that had only one branch was not being correctly
1200        recognized as an item that could match an empty string. This meant that an
1201        enclosing group might also not be so recognized, causing infinite looping
1202        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1203        with the subject "ab", where knowledge that the repeated group can match
1204        nothing is needed in order to break the loop.
1205    
1206    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1207        exec(), but without supplying a callout function, matching went wrong.
1208    
1209    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1210        leak if the size of the offset vector was greater than 30. When the vector
1211        is smaller, the saved offsets during recursion go onto a local stack
1212        vector, but for larger vectors malloc() is used. It was failing to free
1213        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1214        error, in fact).
1215    
1216    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1217        heapframe that is used only when UTF-8 support is enabled. This caused no
1218        problem, but was untidy.
1219    
1220    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1221        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1222        included within another project.
1223    
1224    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1225        slightly modified by me:
1226    
1227          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1228              not building pcregrep.
1229    
1230          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1231              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1232    
1233    25. Forward references, both numeric and by name, in patterns that made use of
1234        duplicate group numbers, could behave incorrectly or give incorrect errors,
1235        because when scanning forward to find the reference group, PCRE was not
1236        taking into account the duplicate group numbers. A pattern such as
1237        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1238    
1239    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1240        the feature of a custom pointer more persuasive (as requested by a user).
1241    
1242    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1243        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1244        pre-defined.
1245    
1246    28. Added support for (*UTF8) at the start of a pattern.
1247    
1248    29. Arrange for flags added by the "release type" setting in CMake to be shown
1249        in the configuration summary.
1250    
1251    
1252    Version 7.8 05-Sep-08
1253    ---------------------
1254    
1255    1.  Replaced UCP searching code with optimized version as implemented for Ad
1256        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1257        stage table and inline lookup instead of a function, giving speed ups of 2
1258        to 5 times on some simple patterns that I tested. Permission was given to
1259        distribute the MultiStage2.py script that generates the tables (it's not in
1260        the tarball, but is in the Subversion repository).
1261    
1262    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1263        scripts.
1264    
1265    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1266        a group with a zero qualifier. The result of the study could be incorrect,
1267        or the function might crash, depending on the pattern.
1268    
1269    4.  Caseless matching was not working for non-ASCII characters in back
1270        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1271        It now works when Unicode Property Support is available.
1272    
1273    5.  In pcretest, an escape such as \x{de} in the data was always generating
1274        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1275        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1276        truncation.
1277    
1278    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1279    
1280    7.  Added two (int) casts to pcregrep when printing the difference of two
1281        pointers, in case they are 64-bit values.
1282    
1283    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1284        test 2 if it fails.
1285    
1286    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1287        and a #define of that name to empty if it is not externally set. This is to
1288        allow users of MSVC to set it if necessary.
1289    
1290    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1291        the convenience functions in the pcre_get.c source file.
1292    
1293    11. An option change at the start of a pattern that had top-level alternatives
1294        could cause overwriting and/or a crash. This command provoked a crash in
1295        some environments:
1296    
1297          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1298    
1299        This potential security problem was recorded as CVE-2008-2371.
1300    
1301    12. For a pattern where the match had to start at the beginning or immediately
1302        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1303        pcre_dfa_exec() could read past the end of the passed subject if there was
1304        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1305        pcretest so that it places the subject at the end of its malloc-ed buffer.
1306    
1307    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1308        exec() might read past the end of the data buffer in UTF-8 mode.
1309    
1310    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1311        the data contained the byte 0x85 as part of a UTF-8 character within its
1312        first line. This applied both to normal and DFA matching.
1313    
1314    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1315        /^[^d]*?$/8 failed to match "abc".
1316    
1317    16. Added a missing copyright notice to pcrecpp_internal.h.
1318    
1319    17. Make it more clear in the documentation that values returned from
1320        pcre_exec() in ovector are byte offsets, not character counts.
1321    
1322    18. Tidied a few places to stop certain compilers from issuing warnings.
1323    
1324    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1325        supplied by Stefan Weber. I made a further small update for 7.8 because
1326        there is a change of source arrangements: the pcre_searchfuncs.c module is
1327        replaced by pcre_ucd.c.
1328    
1329    
1330    Version 7.7 07-May-08
1331    ---------------------
1332    
1333    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1334        a string to a long long, pretend we don't even have a long long." This is
1335        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1336    
1337    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1338        pre-7.6 versions, which defined a global no_arg variable instead of putting
1339        it in the RE class. (See also #8 below.)
1340    
1341    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1342        Lopes.
1343    
1344    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1345    
1346        (1) The include/exclude patterns were being applied to the whole pathnames
1347            of files, instead of just to the final components.
1348    
1349        (2) If there was more than one level of directory, the subdirectories were
1350            skipped unless they satisfied the include/exclude conditions. This is
1351            inconsistent with GNU grep (and could even be seen as contrary to the
1352            pcregrep specification - which I improved to make it absolutely clear).
1353            The action now is always to scan all levels of directory, and just
1354            apply the include/exclude patterns to regular files.
1355    
1356    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1357        --exclude_dir in the tests to avoid scanning .svn directories.
1358    
1359    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1360        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1361        doesn't support NULs in patterns.
1362    
1363    7.  Added some missing "const"s to declarations of static tables in
1364        pcre_compile.c and pcre_dfa_exec.c.
1365    
1366    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1367        caused by fix #2  above. (Subsequently also a second patch to fix the
1368        first patch. And a third patch - this was a messy problem.)
1369    
1370    9.  Applied Craig's patch to remove the use of push_back().
1371    
1372    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1373        matching function regexec().
1374    
1375    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1376        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1377        references. PCRE supports relative numbers with this syntax (I don't think
1378        Oniguruma does).
1379    
1380    12. Previously, a group with a zero repeat such as (...){0} was completely
1381        omitted from the compiled regex. However, this means that if the group
1382        was called as a subroutine from elsewhere in the pattern, things went wrong
1383        (an internal error was given). Such groups are now left in the compiled
1384        pattern, with a new opcode that causes them to be skipped at execution
1385        time.
1386    
1387    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1388        to the way PCRE behaves:
1389    
1390        (a) A lone ] character is dis-allowed (Perl treats it as data).
1391    
1392        (b) A back reference to an unmatched subpattern matches an empty string
1393            (Perl fails the current match path).
1394    
1395        (c) A data ] in a character class must be notated as \] because if the
1396            first data character in a class is ], it defines an empty class. (In
1397            Perl it is not possible to have an empty class.) The empty class []
1398            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1399            The negative empty class [^] matches any one character, independently
1400            of the DOTALL setting.
1401    
1402    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1403        non-existent subpattern following a character class starting with ']' and
1404        containing () gave an internal compiling error instead of "reference to
1405        non-existent subpattern". Fortunately, when the pattern did exist, the
1406        compiled code was correct. (When scanning forwards to check for the
1407        existencd of the subpattern, it was treating the data ']' as terminating
1408        the class, so got the count wrong. When actually compiling, the reference
1409        was subsequently set up correctly.)
1410    
1411    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1412        it was being rejected as not supported by pcre_dfa_exec(), even though
1413        other assertions are supported. I have made pcre_dfa_exec() support
1414        (*FAIL).
1415    
1416    16. The implementation of 13c above involved the invention of a new opcode,
1417        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1418        cannot be changed at match time, I realized I could make a small
1419        improvement to matching performance by compiling OP_ALLANY instead of
1420        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1421        on the OP_ANY path.
1422    
1423    17. Compiling pcretest on Windows with readline support failed without the
1424        following two fixes: (1) Make the unistd.h include conditional on
1425        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1426    
1427    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1428        ncurses library to be included for pcretest when ReadLine support is
1429        requested, but also to allow for it to be overridden. This patch came from
1430        Daniel Bergström.
1431    
1432    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1433        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1434        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1435        spotting this.
1436    
1437    
1438    Version 7.6 28-Jan-08
1439    ---------------------
1440    
1441    1.  A character class containing a very large number of characters with
1442        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1443        overflow.
1444    
1445    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1446        HAVE_LONG_LONG is not defined.
1447    
1448    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1449        bring them up to date and include new features. This patch includes:
1450    
1451        - Fixed PH's badly added libz and libbz2 support.
1452        - Fixed a problem with static linking.
1453        - Added pcredemo. [But later removed - see 7 below.]
1454        - Fixed dftables problem and added an option.
1455        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1456            HAVE_LONG_LONG.
1457        - Added readline support for pcretest.
1458        - Added an listing of the option settings after cmake has run.
1459    
1460    4.  A user submitted a patch to Makefile that makes it easy to create
1461        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1462        Makefile.am that cause it to include this special target, without
1463        affecting anything else. Note that the same mingw target plus all
1464        the other distribution libraries and programs are now supported
1465        when configuring with CMake (see 6 below) instead of with
1466        Configure/Make.
1467    
1468    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1469        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1470        exported in the Windows port". It has not yet been confirmed that the patch
1471        solves the problem, but it does no harm.
1472    
1473    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1474        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1475        with CMake, and also correct the comment about stack recursion.
1476    
1477    7.  Remove the automatic building of pcredemo from the ./configure system and
1478        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1479        of a program that users should build themselves after PCRE is installed, so
1480        building it automatically is not really right. What is more, it gave
1481        trouble in some build environments.
1482    
1483    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1484    
1485    
1486    Version 7.5 10-Jan-08
1487  ---------------------  ---------------------
1488    
1489  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1490      values in parens when parsing an RE using the C++ wrapper."      values in parens when parsing an RE using the C++ wrapper."
1491    
1492  2.  Negative specials like \S did not work in character classes in UTF-8 mode.  2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1493      Characters greater than 255 were excluded from the class instead of being      Characters greater than 255 were excluded from the class instead of being
1494      included.      included.
1495    
1496    3.  The same bug as (2) above applied to negated POSIX classes such as
1497        [:^space:].
1498    
1499    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1500        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1501        I have changed it.
1502    
1503    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1504        first named subpattern) and a construct such as (?&a) would reference the
1505        first named subpattern whose name started with "a" (in other words, the
1506        length check was missing). Both these problems are fixed. "Subpattern name
1507        expected" is now given for (?&) (a zero-length name), and this patch also
1508        makes it give the same error for \k'' (previously it complained that that
1509        was a reference to a non-existent subpattern).
1510    
1511    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1512        this is right because (?- can be followed by option settings as well as by
1513        digits. I have, however, made the messages clearer.
1514    
1515    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1516        than the number used in the conditional) now cause a compile-time error.
1517        This is actually not compatible with Perl, which accepts such patterns, but
1518        treats the conditional as always being FALSE (as PCRE used to), but it
1519        seems to me that giving a diagnostic is better.
1520    
1521    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1522        and messages.
1523    
1524    9.  Fix two occurrences of "backslash" in comments that should have been
1525        "backspace".
1526    
1527    10. Remove two redundant lines of code that can never be obeyed (their function
1528        was moved elsewhere).
1529    
1530    11. The program that makes PCRE's Unicode character property table had a bug
1531        which caused it to generate incorrect table entries for sequences of
1532        characters that have the same character type, but are in different scripts.
1533        It amalgamated them into a single range, with the script of the first of
1534        them. In other words, some characters were in the wrong script. There were
1535        thirteen such cases, affecting characters in the following ranges:
1536    
1537          U+002b0 - U+002c1
1538          U+0060c - U+0060d
1539          U+0061e - U+00612
1540          U+0064b - U+0065e
1541          U+0074d - U+0076d
1542          U+01800 - U+01805
1543          U+01d00 - U+01d77
1544          U+01d9b - U+01dbf
1545          U+0200b - U+0200f
1546          U+030fc - U+030fe
1547          U+03260 - U+0327f
1548          U+0fb46 - U+0fbb1
1549          U+10450 - U+1049d
1550    
1551    12. The -o option (show only the matching part of a line) for pcregrep was not
1552        compatible with GNU grep in that, if there was more than one match in a
1553        line, it showed only the first of them. It now behaves in the same way as
1554        GNU grep.
1555    
1556    13. If the -o and -v options were combined for pcregrep, it printed a blank
1557        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1558        does the same. The return code can be used to tell if there were any
1559        non-matching lines.
1560    
1561    14. Added --file-offsets and --line-offsets to pcregrep.
1562    
1563    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1564        infinitely looping recursion. The bug was that positive lookaheads were not
1565        being skipped when checking for a possible empty match (negative lookaheads
1566        and both kinds of lookbehind were skipped).
1567    
1568    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1569        inclusion of <windows.h> to before rather than after the definition of
1570        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1571    
1572    17. Specifying a possessive quantifier with a specific limit for a Unicode
1573        character property caused pcre_compile() to compile bad code, which led at
1574        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1575        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1576        caused the error; without that there was no problem.
1577    
1578    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1579    
1580    19. Added --enable-pcretest-libreadline.
1581    
1582    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1583        RE::GlobalReplace(). As a result, the number of replacements returned was
1584        double what it should be. I removed one of the increments, but Craig sent a
1585        later patch that removed the other one (the right fix) and added unit tests
1586        that check the return values (which was not done before).
1587    
1588    21. Several CMake things:
1589    
1590        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1591            the names libpcre and libpcreposix, not just pcre and pcreposix.
1592    
1593        (2) The above change means that pcretest and pcregrep are now correctly
1594            linked with the newly-built libraries, not previously installed ones.
1595    
1596        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1597    
1598    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1599        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1600        UTF-8 newline character). The key issue is that the pattern starts .*;
1601        this means that the match must be either at the beginning, or after a
1602        newline. The bug was in the code for advancing after a failed match and
1603        checking that the new position followed a newline. It was not taking
1604        account of UTF-8 characters correctly.
1605    
1606    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1607        character classes. PCRE was not treating the sequence [:...:] as a
1608        character class unless the ... were all letters. Perl, however, seems to
1609        allow any characters between [: and :], though of course it rejects as
1610        unknown any "names" that contain non-letters, because all the known class
1611        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1612        for example, whereas PCRE did not - it did not recognize a POSIX character
1613        class. This seemed a bit dangerous, so the code has been changed to be
1614        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1615        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1616        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1617        Perl does, and where it didn't before.
1618    
1619    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1620        Windows environments %n is disabled by default.
1621    
1622    
1623  Version 7.4 21-Sep-07  Version 7.4 21-Sep-07
1624  ---------------------  ---------------------

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