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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.3 05-Jul-07  Version 8.22
5    ------------
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
10    2.  Fixed a bug in the code for calculating the fixed length of lookbehind
11        assertions.
14    Version 8.21 12-Dec-2011
15    ------------------------
17    1.  Updating the JIT compiler.
19    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
20        are added as well.
22    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
23        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
24        calling _pcre_jit_exec. Some extra comments are added.
26    4.  (*MARK) settings inside atomic groups that do not contain any capturing
27        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
28        was introduced by change 18 for 8.20.
30    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
31        ECMA-262 standard.
33    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
34        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
35        This bug was probably introduced by change 9 of 8.13.
37    7.  While fixing 6 above, I noticed that a number of other items were being
38        incorrectly rejected as "not fixed length". This arose partly because newer
39        opcodes had not been added to the fixed-length checking code. I have (a)
40        corrected the bug and added tests for these items, and (b) arranged for an
41        error to occur if an unknown opcode is encountered while checking for fixed
42        length instead of just assuming "not fixed length". The items that were
43        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
44        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
45        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
47    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
48        being incorrectly compiled and would have given unpredicatble results.
50    9.  A possessively repeated subpattern with minimum repeat count greater than
51        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
52        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
53        the first (A) could occur when it should not.
55    10. Add a cast and remove a redundant test from the code.
57    11. JIT should use pcre_malloc/pcre_free for allocation.
59    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
60        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
61        is anything other than /usr, -L is still shown).
63    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
65    14. Perl does not support \N without a following name in a [] class; PCRE now
66        also gives an error.
68    15. If a forward reference was repeated with an upper limit of around 2000,
69        it caused the error "internal error: overran compiling workspace". The
70        maximum number of forward references (including repeats) was limited by the
71        internal workspace, and dependent on the LINK_SIZE. The code has been
72        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
73        the default depends on LINK_SIZE. There is a new upper limit (for safety)
74        of around 200,000 forward references. While doing this, I also speeded up
75        the filling in of repeated forward references.
77    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
78        incorrectly expecting the subject to contain another "a" after the start.
80    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
81        in the match, the SKIP should be ignored. This was not happening; instead
82        the SKIP was being treated as NOMATCH. For patterns such as
83        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
84        tested.
86    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
87        now much more compatible with Perl, in particular in cases where the result
88        is a non-match for a non-anchored pattern. For example, if
89        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
90        "m", where previously it did not return a name. A side effect of this
91        change is that for partial matches, the last encountered mark name is
92        returned, as for non matches. A number of tests that were previously not
93        Perl-compatible have been moved into the Perl-compatible test files. The
94        refactoring has had the pleasing side effect of removing one argument from
95        the match() function, thus reducing its stack requirements.
97    19. If the /S+ option was used in pcretest to study a pattern using JIT,
98        subsequent uses of /S (without +) incorrectly behaved like /S+.
100    21. Retrieve executable code size support for the JIT compiler and fixing
101        some warnings.
103    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
104        not work when the shorter character appeared right at the end of the
105        subject string.
107    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
108        systems.
110    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
111        output it when the /M option is used in pcretest.
113    25. The CheckMan script was not being included in the distribution. Also, added
114        an explicit "perl" to run Perl scripts from the PrepareRelease script
115        because this is reportedly needed in Windows.
117    26. If study data was being save in a file and studying had not found a set of
118        "starts with" bytes for the pattern, the data written to the file (though
119        never used) was taken from uninitialized memory and so caused valgrind to
120        complain.
122    27. Updated RunTest.bat as provided by Sheri Pierce.
124    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
126    29. Computation of memory usage for the table of capturing group names was
127        giving an unnecessarily large value.
130    Version 8.20 21-Oct-2011
131    ------------------------
133    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
134        a POSIX class. After further experiments with Perl, which convinced me that
135        Perl has bugs and confusions, a closing square bracket is no longer allowed
136        in a POSIX name. This bug also affected patterns with classes that started
137        with full stops.
139    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
140        captured substring, but while checking the failing first alternative,
141        substring 1 is temporarily captured. If the output vector supplied to
142        pcre_exec() was not big enough for this capture, the yield of the function
143        was still zero ("insufficient space for captured substrings"). This cannot
144        be totally fixed without adding another stack variable, which seems a lot
145        of expense for a edge case. However, I have improved the situation in cases
146        such as /(a)(b)x|abc/ matched against "abc", where the return code
147        indicates that fewer than the maximum number of slots in the ovector have
148        been set.
150    3.  Related to (2) above: when there are more back references in a pattern than
151        slots in the output vector, pcre_exec() uses temporary memory during
152        matching, and copies in the captures as far as possible afterwards. It was
153        using the entire output vector, but this conflicts with the specification
154        that only 2/3 is used for passing back captured substrings. Now it uses
155        only the first 2/3, for compatibility. This is, of course, another edge
156        case.
158    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
159        main code base, and can be used by building with --enable-jit. When this is
160        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
161        runtime --no-jit option is given.
163    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
164        ovector, the return from the function was zero, implying that there were
165        other matches that did not fit. The correct "exactly full" value is now
166        returned.
168    6.  If a subpattern that was called recursively or as a subroutine contained
169        (*PRUNE) or any other control that caused it to give a non-standard return,
170        invalid errors such as "Error -26 (nested recursion at the same subject
171        position)" or even infinite loops could occur.
173    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
174        computing the minimum length on reaching *ACCEPT, and so ended up with the
175        wrong value of 1 rather than 0. Further investigation indicates that
176        computing a minimum subject length in the presence of *ACCEPT is difficult
177        (think back references, subroutine calls), and so I have changed the code
178        so that no minimum is registered for a pattern that contains *ACCEPT.
180    8.  If (*THEN) was present in the first (true) branch of a conditional group,
181        it was not handled as intended. [But see 16 below.]
183    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
184        Sheri Pierce.
186    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
187        the first byte in a match must be "a".
189    11. Change 17 for 8.13 increased the recursion depth for patterns like
190        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
191        pattern contains any instances of (*THEN). If it does not, the old
192        optimizations are restored. It would be nice to do this on a per-group
193        basis, but at the moment that is not feasible.
195    12. In some environments, the output of pcretest -C is CRLF terminated. This
196        broke RunTest's code that checks for the link size. A single white space
197        character after the value is now allowed for.
199    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
200        For "fr", it uses the Windows-specific input and output files.
202    14. If (*THEN) appeared in a group that was called recursively or as a
203        subroutine, it did not work as intended. [But see next item.]
205    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
206        pattern fragments (but not containing any | characters). If A and B are
207        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
208        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
209        D. In other words, Perl considers parentheses that do not contain any |
210        characters to be part of a surrounding alternative, whereas PCRE was
211        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
212        differently. PCRE now behaves in the same way as Perl, except in the case
213        of subroutine/recursion calls such as (?1) which have in any case always
214        been different (but PCRE had them first :-).
216    16. Related to 15 above: Perl does not treat the | in a conditional group as
217        creating alternatives. Such a group is treated in the same way as an
218        ordinary group without any | characters when processing (*THEN). PCRE has
219        been changed to match Perl's behaviour.
221    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
222        RunGrepTest script failed.
224    18. Change 22 for version 13 caused atomic groups to use more stack. This is
225        inevitable for groups that contain captures, but it can lead to a lot of
226        stack use in large patterns. The old behaviour has been restored for atomic
227        groups that do not contain any capturing parentheses.
229    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
230        suppress the check for a minimum subject length at run time. (If it was
231        given to pcre_exec() or pcre_dfa_exec() it did work.)
233    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
234        fail to work when decoding hex characters in data strings in EBCDIC
235        environments.
237    21. It appears that in at least one Mac OS environment, the isxdigit() function
238        is implemented as a macro that evaluates to its argument more than once,
239        contravening the C 90 Standard (I haven't checked a later standard). There
240        was an instance in pcretest which caused it to go wrong when processing
241        \x{...} escapes in subject strings. The has been rewritten to avoid using
242        things like p++ in the argument of isxdigit().
245    Version 8.13 16-Aug-2011
246    ------------------------
248    1.  The Unicode data tables have been updated to Unicode 6.0.0.
250    2.  Two minor typos in pcre_internal.h have been fixed.
252    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
253        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
254        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
256    4.  There were a number of related bugs in the code for matching backrefences
257        caselessly in UTF-8 mode when codes for the characters concerned were
258        different numbers of bytes. For example, U+023A and U+2C65 are an upper
259        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
260        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
261        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
262        2-byte code at the end of the subject (it thought there wasn't enough data
263        left).
265    5.  Comprehensive information about what went wrong is now returned by
266        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
267        as the output vector has at least 2 elements. The offset of the start of
268        the failing character and a reason code are placed in the vector.
270    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
271        now returned is for the first byte of the failing character, instead of the
272        last byte inspected. This is an incompatible change, but I hope it is small
273        enough not to be a problem. It makes the returned offset consistent with
274        pcre_exec() and pcre_dfa_exec().
276    7.  pcretest now gives a text phrase as well as the error number when
277        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
278        failure, the offset and reason code are output.
280    8.  When \R was used with a maximizing quantifier it failed to skip backwards
281        over a \r\n pair if the subsequent match failed. Instead, it just skipped
282        back over a single character (\n). This seems wrong (because it treated the
283        two characters as a single entity when going forwards), conflicts with the
284        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
285        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
286        has been changed.
288    9.  Some internal refactoring has changed the processing so that the handling
289        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
290        time (the PCRE_DOTALL option was changed this way some time ago: version
291        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
292        which was always a bit of a fudge. It also means that there is one less
293        argument for the match() function, which reduces its stack requirements
294        slightly. This change also fixes an incompatibility with Perl: the pattern
295        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
297    10. More internal refactoring has drastically reduced the number of recursive
298        calls to match() for possessively repeated groups such as (abc)++ when
299        using pcre_exec().
301    11. While implementing 10, a number of bugs in the handling of groups were
302        discovered and fixed:
304        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
305        (a|)*(?1) gave a compile-time internal error.
306        ((a|)+)+  did not notice that the outer group could match an empty string.
307        (^a|^)+   was not marked as anchored.
308        (.*a|.*)+ was not marked as matching at start or after a newline.
310    12. Yet more internal refactoring has removed another argument from the match()
311        function. Special calls to this function are now indicated by setting a
312        value in a variable in the "match data" data block.
314    13. Be more explicit in pcre_study() instead of relying on "default" for
315        opcodes that mean there is no starting character; this means that when new
316        ones are added and accidentally left out of pcre_study(), testing should
317        pick them up.
319    14. The -s option of pcretest has been documented for ages as being an old
320        synonym of -m (show memory usage). I have changed it to mean "force study
321        for every regex", that is, assume /S for every regex. This is similar to -i
322        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
323        using it. It makes it easier to run collections of tests with and without
324        study enabled, and thereby test pcre_study() more easily. All the standard
325        tests are now run with and without -s (but some patterns can be marked as
326        "never study" - see 20 below).
328    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
329        restoration of the capturing data to the outer values was not happening
330        correctly.
332    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
333        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
334        pattern had matched an empty string, and so incorrectly returned a no
335        match.
337    17. There was optimizing code for the last branch of non-capturing parentheses,
338        and also for the obeyed branch of a conditional subexpression, which used
339        tail recursion to cut down on stack usage. Unfortunately, now that there is
340        the possibility of (*THEN) occurring in these branches, tail recursion is
341        no longer possible because the return has to be checked for (*THEN). These
342        two optimizations have therefore been removed. [But see 8.20/11 above.]
344    18. If a pattern containing \R was studied, it was assumed that \R always
345        matched two bytes, thus causing the minimum subject length to be
346        incorrectly computed because \R can also match just one byte.
348    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
349        was incorrectly computed.
351    20. If /S is present twice on a test pattern in pcretest input, it now
352        *disables* studying, thereby overriding the use of -s on the command line
353        (see 14 above). This is necessary for one or two tests to keep the output
354        identical in both cases.
356    21. When (*ACCEPT) was used in an assertion that matched an empty string and
357        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
359    22. When an atomic group that contained a capturing parenthesis was
360        successfully matched, but the branch in which it appeared failed, the
361        capturing was not being forgotten if a higher numbered group was later
362        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
363        group 1 to "a", when in fact it should be unset. This applied to multi-
364        branched capturing and non-capturing groups, repeated or not, and also to
365        positive assertions (capturing in negative assertions does not happen
366        in PCRE) and also to nested atomic groups.
368    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
369        subject after a captured substring, to make it easier to tell which of a
370        number of identical substrings has been captured.
372    24. The way atomic groups are processed by pcre_exec() has been changed so that
373        if they are repeated, backtracking one repetition now resets captured
374        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
375        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
376        "aaa". Previously, it would have been "a". As part of this code
377        refactoring, the way recursive calls are handled has also been changed.
379    25. If an assertion condition captured any substrings, they were not passed
380        back unless some other capturing happened later. For example, if
381        (?(?=(a))a) was matched against "a", no capturing was returned.
383    26. When studying a pattern that contained subroutine calls or assertions,
384        the code for finding the minimum length of a possible match was handling
385        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
386        group 1 called group 2 while simultaneously a separate group 2 called group
387        1). A stack overflow occurred in this case. I have fixed this by limiting
388        the recursion depth to 10.
390    27. Updated RunTest.bat in the distribution to the version supplied by Tom
391        Fortmann. This supports explicit test numbers on the command line, and has
392        argument validation and error reporting.
394    28. An instance of \X with an unlimited repeat could fail if at any point the
395        first character it looked at was a mark character.
397    29. Some minor code refactoring concerning Unicode properties and scripts
398        should reduce the stack requirement of match() slightly.
400    30. Added the '=' option to pcretest to check the setting of unused capturing
401        slots at the end of the pattern, which are documented as being -1, but are
402        not included in the return count.
404    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
405        compiled something random. Now it gives a compile-time error (as does
406        Perl).
408    32. A *MARK encountered during the processing of a positive assertion is now
409        recorded and passed back (compatible with Perl).
411    33. If --only-matching or --colour was set on a pcregrep call whose pattern
412        had alternative anchored branches, the search for a second match in a line
413        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
414        matched the line "0102" twice. The same bug affected patterns that started
415        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
416        twice.
418    34. Previously, PCRE did not allow quantification of assertions. However, Perl
419        does, and because of capturing effects, quantifying parenthesized
420        assertions may at times be useful. Quantifiers are now allowed for
421        parenthesized assertions.
423    35. A minor code tidy in pcre_compile() when checking options for \R usage.
425    36. \g was being checked for fancy things in a character class, when it should
426        just be a literal "g".
428    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
429        appearance of a nested POSIX class supersedes an apparent external class.
430        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
431        unescaped square brackets may also appear as part of class names. For
432        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
433        more like Perl. (But see 8.20/1 above.)
435    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
436        was because it thought it was \N{name}, which is not supported).
438    39. Add minix to OS list not supporting the -S option in pcretest.
440    40. PCRE tries to detect cases of infinite recursion at compile time, but it
441        cannot analyze patterns in sufficient detail to catch mutual recursions
442        such as ((?1))((?2)). There is now a runtime test that gives an error if a
443        subgroup is called recursively as a subpattern for a second time at the
444        same position in the subject string. In previous releases this might have
445        been caught by the recursion limit, or it might have run out of stack.
447    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
448        happen only once. PCRE was, however incorrectly giving a compile time error
449        "recursive call could loop indefinitely" because it cannot analyze the
450        pattern in sufficient detail. The compile time test no longer happens when
451        PCRE is compiling a conditional subpattern, but actual runaway loops are
452        now caught at runtime (see 40 above).
454    42. It seems that Perl allows any characters other than a closing parenthesis
455        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
456        has been changed to be the same.
458    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
459        as not to get warnings when autogen.sh is called. Also changed
460        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
462    44. To help people who use pcregrep to scan files containing exceedingly long
463        lines, the following changes have been made:
465        (a) The default value of the buffer size parameter has been increased from
466            8K to 20K. (The actual buffer used is three times this size.)
468        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
469            PCRE is built.
471        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
472            to be set at run time.
474        (d) Numerical values in pcregrep options can be followed by K or M, for
475            example --buffer-size=50K.
477        (e) If a line being scanned overflows pcregrep's buffer, an error is now
478            given and the return code is set to 2.
480    45. Add a pointer to the latest mark to the callout data block.
482    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
483        partial match of an empty string instead of no match. This was specific to
484        the use of ".".
486    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
487        complete match instead of a partial match. This bug was dependent on both
488        the PCRE_UTF8 and PCRE_DOTALL options being set.
490    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
491        starting byte set, because \b was not being ignored.
494    Version 8.12 15-Jan-2011
495    ------------------------
497    1.  Fixed some typos in the markup of the man pages, and wrote a script that
498        checks for such things as part of the documentation building process.
500    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
501        --match-limit and --recursion-limit options (added for 8.11). In
502        particular, this made one of the standard tests fail. (The integer value
503        went into the wrong half of a long int.)
505    3.  If the --colour option was given to pcregrep with -v (invert match), it
506        did strange things, either producing crazy output, or crashing. It should,
507        of course, ignore a request for colour when reporting lines that do not
508        match.
510    4.  Another pcregrep bug caused similar problems if --colour was specified with
511        -M (multiline) and the pattern match finished with a line ending.
513    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
514        matched in multiline mode, the following line was shown as part of the
515        match. This seems wrong, so I have changed it.
517    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
518        the check for further matches in the same line (so they could be coloured)
519        to overrun the end of the current line. If another match was found, it was
520        incorrectly shown (and then shown again when found in the next line).
522    7.  If pcregrep was compiled under Windows, there was a reference to the
523        function pcregrep_exit() before it was defined. I am assuming this was
524        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
525        reported by a user. I've moved the definition above the reference.
528    Version 8.11 10-Dec-2010
529    ------------------------
531    1.  (*THEN) was not working properly if there were untried alternatives prior
532        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
533        backtracked to try for "b" instead of moving to the next alternative branch
534        at the same level (in this case, to look for "c"). The Perl documentation
535        is clear that when (*THEN) is backtracked onto, it goes to the "next
536        alternative in the innermost enclosing group".
538    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
539        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
540        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
541        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
542        (*THEN).
544    3.  If \s appeared in a character class, it removed the VT character from
545        the class, even if it had been included by some previous item, for example
546        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
547        of \s, but is part of the POSIX "space" class.)
549    4.  A partial match never returns an empty string (because you can always
550        match an empty string at the end of the subject); however the checking for
551        an empty string was starting at the "start of match" point. This has been
552        changed to the "earliest inspected character" point, because the returned
553        data for a partial match starts at this character. This means that, for
554        example, /(?<=abc)def/ gives a partial match for the subject "abc"
555        (previously it gave "no match").
557    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
558        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
559        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
560        has an implication that the given string is incomplete (because a partial
561        match is preferred over a full match). For this reason, these items now
562        give a partial match in this situation. [Aside: previously, the one case
563        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
564        match rather than a full match, which was wrong by the old rules, but is
565        now correct.]
567    6.  There was a bug in the handling of #-introduced comments, recognized when
568        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
569        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
570        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
571        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
572        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
573        places in pcre_compile().
575    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
576        comments when looking ahead for named forward references to subpatterns,
577        the only newline sequence it recognized was NL. It now handles newlines
578        according to the set newline convention.
580    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
581        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
582        cater for a lack of strerror(). These oversights have been fixed.
584    9.  Added --match-limit and --recursion-limit to pcregrep.
586    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
588    11. When the -o option was used, pcregrep was setting a return code of 1, even
589        when matches were found, and --line-buffered was not being honoured.
591    12. Added an optional parentheses number to the -o and --only-matching options
592        of pcregrep.
594    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
595        can match an empty string. The code to do it in pcretest and pcredemo
596        needed fixing:
598        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
599            only one byte after an empty string match just before CRLF (this case
600            just got forgotten; "any" and "anycrlf" were OK).
602        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
603            mode when an empty string match preceded an ASCII character followed by
604            a non-ASCII character. (The code for advancing by one character rather
605            than one byte was nonsense.)
607        (c) The pcredemo.c sample program did not have any code at all to handle
608            the cases when CRLF is a valid newline sequence.
610    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
611        as a starting offset was within the subject string. There is now a new
612        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
613        negative or greater than the length of the string. In order to test this,
614        pcretest is extended to allow the setting of negative starting offsets.
616    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
617        starting offset points to the beginning of a UTF-8 character was
618        unnecessarily clumsy. I tidied it up.
620    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
621        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
623    17. Nobody had reported that the --include_dir option, which was added in
624        release 7.7 should have been called --include-dir (hyphen, not underscore)
625        for compatibility with GNU grep. I have changed it to --include-dir, but
626        left --include_dir as an undocumented synonym, and the same for
627        --exclude-dir, though that is not available in GNU grep, at least as of
628        release 2.5.4.
630    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
631        characters from a string of bytes) have been redefined so as not to use
632        loops, in order to improve performance in some environments. At the same
633        time, I abstracted some of the common code into auxiliary macros to save
634        repetition (this should not affect the compiled code).
636    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
637        compile-time error is now given if \c is not followed by an ASCII
638        character, that is, a byte less than 128. (In EBCDIC mode, the code is
639        different, and any byte value is allowed.)
641    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
642        START_OPTIMIZE option, which is now allowed at compile time - but just
643        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
644        to pcregrep and other applications that have no direct access to PCRE
645        options. The new /Y option in pcretest sets this option when calling
646        pcre_compile().
648    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
649        back references. Groups containing recursive back references were forced to
650        be atomic by that change, but in the case of named groups, the amount of
651        memory required was incorrectly computed, leading to "Failed: internal
652        error: code overflow". This has been fixed.
654    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
655        pcretest.c, to avoid build problems in some Borland environments.
658    Version 8.10 25-Jun-2010
659    ------------------------
661    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
662        THEN.
664    2.  (*ACCEPT) was not working when inside an atomic group.
666    3.  Inside a character class, \B is treated as a literal by default, but
667        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
668        causes the error). The code is unchanged, but I tidied the documentation.
670    4.  Inside a character class, PCRE always treated \R and \X as literals,
671        whereas Perl faults them if its -w option is set. I have changed PCRE so
672        that it faults them when PCRE_EXTRA is set.
674    5.  Added support for \N, which always matches any character other than
675        newline. (It is the same as "." when PCRE_DOTALL is not set.)
677    6.  When compiling pcregrep with newer versions of gcc which may have
678        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
679        declared with attribute warn_unused_result" were given. Just casting the
680        result to (void) does not stop the warnings; a more elaborate fudge is
681        needed. I've used a macro to implement this.
683    7.  Minor change to pcretest.c to avoid a compiler warning.
685    8.  Added four artifical Unicode properties to help with an option to make
686        \s etc use properties (see next item). The new properties are: Xan
687        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
689    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
690        use Unicode properties. (*UCP) at the start of a pattern can be used to set
691        this option. Modified pcretest to add /W to test this facility. Added
692        REG_UCP to make it available via the POSIX interface.
694    10. Added --line-buffered to pcregrep.
696    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
697        studied, and the match started with a letter with a code point greater than
698        127 whose first byte was different to the first byte of the other case of
699        the letter, the other case of this starting letter was not recognized
700        (#976).
702    12. If a pattern that was studied started with a repeated Unicode property
703        test, for example, \p{Nd}+, there was the theoretical possibility of
704        setting up an incorrect bitmap of starting bytes, but fortunately it could
705        not have actually happened in practice until change 8 above was made (it
706        added property types that matched character-matching opcodes).
708    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
709        possible starting bytes for non-anchored patterns.
711    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
712        \R, and also a number of cases that involve Unicode properties, both
713        explicit and implicit when PCRE_UCP is set.
715    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
716        input, it could crash or give wrong results if characters with values
717        greater than 0xc0 were present in the subject string. (Detail: it assumed
718        UTF-8 input when processing these items.)
720    16. Added a lot of (int) casts to avoid compiler warnings in systems where
721        size_t is 64-bit (#991).
723    17. Added a check for running out of memory when PCRE is compiled with
724        --disable-stack-for-recursion (#990).
726    18. If the last data line in a file for pcretest does not have a newline on
727        the end, a newline was missing in the output.
729    19. The default pcre_chartables.c file recognizes only ASCII characters (values
730        less than 128) in its various bitmaps. However, there is a facility for
731        generating tables according to the current locale when PCRE is compiled. It
732        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
733        characters, are recognized by isspace() and therefore were getting set in
734        these tables, and indeed these tables seem to approximate to ISO 8859. This
735        caused a problem in UTF-8 mode when pcre_study() was used to create a list
736        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
737        which of course cannot start UTF-8 characters. I have changed the code so
738        that only real ASCII characters (less than 128) and the correct starting
739        bytes for UTF-8 encodings are set for characters greater than 127 when in
740        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
741        altogether.)
743    20. Added the /T option to pcretest so as to be able to run tests with non-
744        standard character tables, thus making it possible to include the tests
745        used for 19 above in the standard set of tests.
747    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
748        reference to a subpattern the other side of a comment that contains an
749        opening parenthesis caused either an internal compiling error, or a
750        reference to the wrong subpattern.
753    Version 8.02 19-Mar-2010
754    ------------------------
756    1.  The Unicode data tables have been updated to Unicode 5.2.0.
758    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
759        configured.
761    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
762        original author of that file, following a query about its status.
764    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
765        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
767    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
768        quantifier applied to a forward-referencing subroutine call, could compile
769        incorrect code or give the error "internal error: previously-checked
770        referenced subpattern not found".
772    6.  Both MS Visual Studio and Symbian OS have problems with initializing
773        variables to point to external functions. For these systems, therefore,
774        pcre_malloc etc. are now initialized to local functions that call the
775        relevant global functions.
777    7.  There were two entries missing in the vectors called coptable and poptable
778        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
779        I've fixed the data, and added a kludgy way of testing at compile time that
780        the lengths are correct (equal to the number of opcodes).
782    8.  Following on from 7, I added a similar kludge to check the length of the
783        eint vector in pcreposix.c.
785    9.  Error texts for pcre_compile() are held as one long string to avoid too
786        much relocation at load time. To find a text, the string is searched,
787        counting zeros. There was no check for running off the end of the string,
788        which could happen if a new error number was added without updating the
789        string.
791    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
793    11. \K was not working if it appeared in an atomic group or in a group that
794        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
795        \K is "not well defined" if used in an assertion. PCRE now accepts it if
796        the assertion is positive, but not if it is negative.
798    12. Change 11 fortuitously reduced the size of the stack frame used in the
799        "match()" function of pcre_exec.c by one pointer. Forthcoming
800        implementation of support for (*MARK) will need an extra pointer on the
801        stack; I have reserved it now, so that the stack frame size does not
802        decrease.
804    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
805        item in branch that calls a recursion is a subroutine call - as in the
806        second branch in the above example - was incorrectly given the compile-
807        time error "recursive call could loop indefinitely" because pcre_compile()
808        was not correctly checking the subroutine for matching a non-empty string.
810    14. The checks for overrunning compiling workspace could trigger after an
811        overrun had occurred. This is a "should never occur" error, but it can be
812        triggered by pathological patterns such as hundreds of nested parentheses.
813        The checks now trigger 100 bytes before the end of the workspace.
815    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
818    Version 8.01 19-Jan-2010
819    ------------------------
821    1.  If a pattern contained a conditional subpattern with only one branch (in
822        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
823        computed the wrong minimum data length (which is of course zero for such
824        subpatterns). This could cause incorrect "no match" results.
826    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
827        the pattern is reset in the first branch, pcre_compile() failed with
828        "internal error: code overflow at offset...". This happened only when
829        the reset was to the original external option setting. (An optimization
830        abstracts leading options settings into an external setting, which was the
831        cause of this.)
833    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
834        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
835        assertion pattern did not match (meaning that the assertion was true), it
836        was incorrectly treated as false if the SKIP had been reached during the
837        matching. This also applied to assertions used as conditions.
839    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
840        assertion subpattern, including such a pattern used as a condition,
841        unpredictable results occurred, instead of the error return
844    5.  The C++ GlobalReplace function was not working like Perl for the special
845        situation when an empty string is matched. It now does the fancy magic
846        stuff that is necessary.
848    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
849        removed. (These were left over from very, very early versions of PCRE.)
851    7.  Some cosmetic changes to the code to make life easier when compiling it
852        as part of something else:
854        (a) Change DEBUG to PCRE_DEBUG.
856        (b) In pcre_compile(), rename the member of the "branch_chain" structure
857            called "current" as "current_branch", to prevent a collision with the
858            Linux macro when compiled as a kernel module.
860        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
861            prevent a collision with the Linux macro when compiled as a kernel
862            module.
864    8.  In pcre_compile() there are some checks for integer overflows that used to
865        cast potentially large values to (double). This has been changed to that
866        when building, a check for int64_t is made, and if it is found, it is used
867        instead, thus avoiding the use of floating point arithmetic. (There is no
868        other use of FP in PCRE.) If int64_t is not found, the fallback is to
869        double.
871    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
872        2005 (difference between two addresses compared to an unsigned value).
874    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
875        custom one, because of the following reported problem in Windows:
877          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
878              under Win32.
879          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
880              therefore missing the function definition.
881          - The compiler thus generates a "C" signature for the test function.
882          - The linker fails to find the "C" function.
883          - PCRE fails to configure if asked to do so against libbz2.
885    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
886        messages were output:
888          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
889          rerunning libtoolize, to keep the correct libtool macros in-tree.
890          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
892        I have done both of these things.
894    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
895        most of the time, it *can* run out if it is given a pattern that contains a
896        runaway infinite recursion. I updated the discussion in the pcrestack man
897        page.
899    13. Now that we have gone to the x.xx style of version numbers, the minor
900        version may start with zero. Using 08 or 09 is a bad idea because users
901        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
902        interpreted as invalid octal numbers. I've updated the previous comment in
903        configure.ac, and also added a check that gives an error if 08 or 09 are
904        used.
906    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
907        causing partial matching to fail when the end of the subject matched \W
908        in a UTF-8 pattern where \W was quantified with a minimum of 3.
910    15. There were some discrepancies between the declarations in pcre_internal.h
911        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
912        their definitions. The declarations used "const uschar *" and the
913        definitions used USPTR. Even though USPTR is normally defined as "const
914        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
915        reported that: "This difference in casting confuses some C++ compilers, for
916        example, SunCC recognizes above declarations as different functions and
917        generates broken code for hbpcre." I have changed the declarations to use
918        USPTR.
920    16. GNU libtool is named differently on some systems. The autogen.sh script now
921        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
922        (FreeBSD).
924    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
925        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
926        comment: "Figure out how to create a longlong from a string: strtoll and
927        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
928        instance, but it only takes 2 args instead of 3!"
930    18. A subtle bug concerned with back references has been fixed by a change of
931        specification, with a corresponding code fix. A pattern such as
932        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
933        refers, was giving matches when it shouldn't. For example, xa=xaaa would
934        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
935        same bug. Such groups have to be quantified to be useful, or contained
936        inside another quantified group. (If there's no repetition, the reference
937        can never match.) The problem arises because, having left the group and
938        moved on to the rest of the pattern, a later failure that backtracks into
939        the group uses the captured value from the final iteration of the group
940        rather than the correct earlier one. I have fixed this in PCRE by forcing
941        any group that contains a reference to itself to be an atomic group; that
942        is, there cannot be any backtracking into it once it has completed. This is
943        similar to recursive and subroutine calls.
946    Version 8.00 19-Oct-09
947    ----------------------
949    1.  The table for translating pcre_compile() error codes into POSIX error codes
950        was out-of-date, and there was no check on the pcre_compile() error code
951        being within the table. This could lead to an OK return being given in
952        error.
954    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
955        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
956        in a Windows environment.
958    3.  The pcregrep --count option prints the count for each file even when it is
959        zero, as does GNU grep. However, pcregrep was also printing all files when
960        --files-with-matches was added. Now, when both options are given, it prints
961        counts only for those files that have at least one match. (GNU grep just
962        prints the file name in this circumstance, but including the count seems
963        more useful - otherwise, why use --count?) Also ensured that the
964        combination -clh just lists non-zero counts, with no names.
966    4.  The long form of the pcregrep -F option was incorrectly implemented as
967        --fixed_strings instead of --fixed-strings. This is an incompatible change,
968        but it seems right to fix it, and I didn't think it was worth preserving
969        the old behaviour.
971    5.  The command line items --regex=pattern and --regexp=pattern were not
972        recognized by pcregrep, which required --regex pattern or --regexp pattern
973        (with a space rather than an '='). The man page documented the '=' forms,
974        which are compatible with GNU grep; these now work.
976    6.  No libpcreposix.pc file was created for pkg-config; there was just
977        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
979    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
980        when UCP support is not needed, by modifying the Python script that
981        generates it from Unicode data files. This should not matter if the module
982        is correctly used as a library, but I received one complaint about 50K of
983        unwanted data. My guess is that the person linked everything into his
984        program rather than using a library. Anyway, it does no harm.
986    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
987        was a minimum greater than 1 for a wide character in a possessive
988        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
989        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
990        character. Chaos in the form of incorrect output or a compiling loop could
991        result.
993    9.  The restrictions on what a pattern can contain when partial matching is
994        requested for pcre_exec() have been removed. All patterns can now be
995        partially matched by this function. In addition, if there are at least two
996        slots in the offset vector, the offset of the earliest inspected character
997        for the match and the offset of the end of the subject are set in them when
998        PCRE_ERROR_PARTIAL is returned.
1000    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1001        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1002        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1003        and may be more useful for multi-segment matching.
1005    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1006        used to be given if ever the end of the subject was reached; now it is
1007        given only if matching could not proceed because another character was
1008        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1009        string "Z", which now yields "no match" instead of "partial match". In the
1010        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1011        final character ended with (*FAIL).
1013    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1014        if the pattern had a "must contain" character that was already found in the
1015        earlier partial match, unless partial matching was again requested. For
1016        example, with the pattern /dog.(body)?/, the "must contain" character is
1017        "g". If the first part-match was for the string "dog", restarting with
1018        "sbody" failed. This bug has been fixed.
1020    13. The string returned by pcre_dfa_exec() after a partial match has been
1021        changed so that it starts at the first inspected character rather than the
1022        first character of the match. This makes a difference only if the pattern
1023        starts with a lookbehind assertion or \b or \B (\K is not supported by
1024        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1025        matching functions compatible, and I think it's the right thing to do.
1027    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1028        so that the demonstration program is easily available in environments where
1029        PCRE has not been installed from source.
1031    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1032        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1033        library.
1035    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1036        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1037        is not the first non-POSIX option to be added. Clearly some people find
1038        these options useful.
1040    17. If a caller to the POSIX matching function regexec() passes a non-zero
1041        value for nmatch with a NULL value for pmatch, the value of
1042        nmatch is forced to zero.
1044    18. RunGrepTest did not have a test for the availability of the -u option of
1045        the diff command, as RunTest does. It now checks in the same way as
1046        RunTest, and also checks for the -b option.
1048    19. If an odd number of negated classes containing just a single character
1049        interposed, within parentheses, between a forward reference to a named
1050        subpattern and the definition of the subpattern, compilation crashed with
1051        an internal error, complaining that it could not find the referenced
1052        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1053        [The bug was that it was starting one character too far in when skipping
1054        over the character class, thus treating the ] as data rather than
1055        terminating the class. This meant it could skip too much.]
1057    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1058        /g option in pcretest when the pattern contains \K, which makes it possible
1059        to have an empty string match not at the start, even when the pattern is
1060        anchored. Updated pcretest and pcredemo to use this option.
1062    21. If the maximum number of capturing subpatterns in a recursion was greater
1063        than the maximum at the outer level, the higher number was returned, but
1064        with unset values at the outer level. The correct (outer level) value is
1065        now given.
1067    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1068        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1069        make it do so. The string so far is captured, making this feature
1070        compatible with Perl.
1072    23. The tests have been re-organized, adding tests 11 and 12, to make it
1073        possible to check the Perl 5.10 features against Perl 5.10.
1075    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1076        pattern matches a fixed length string. PCRE did not allow this; now it
1077        does. Neither allows recursion.
1079    25. I finally figured out how to implement a request to provide the minimum
1080        length of subject string that was needed in order to match a given pattern.
1081        (It was back references and recursion that I had previously got hung up
1082        on.) This code has now been added to pcre_study(); it finds a lower bound
1083        to the length of subject needed. It is not necessarily the greatest lower
1084        bound, but using it to avoid searching strings that are too short does give
1085        some useful speed-ups. The value is available to calling programs via
1086        pcre_fullinfo().
1088    26. While implementing 25, I discovered to my embarrassment that pcretest had
1089        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1090        study optimizations had never been tested with that matching function.
1091        Oops. What is worse, even when it was passed study data, there was a bug in
1092        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1093        were also very few tests of studied patterns with pcre_dfa_exec().
1095    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1096        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1097        on the other side of the coin, they are no longer allowed to have different
1098        names, because these cannot be distinguished in PCRE, and this has caused
1099        confusion. (This is a difference from Perl.)
1101    28. When duplicate subpattern names are present (necessarily with different
1102        numbers, as required by 27 above), and a test is made by name in a
1103        conditional pattern, either for a subpattern having been matched, or for
1104        recursion in such a pattern, all the associated numbered subpatterns are
1105        tested, and the overall condition is true if the condition is true for any
1106        one of them. This is the way Perl works, and is also more like the way
1107        testing by number works.
1110    Version 7.9 11-Apr-09
1111    ---------------------
1113    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1114        (pcretest), all targets were linked against these libraries. This included
1115        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1116        libraries. This caused unwanted dependencies to be created. This problem
1117        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1118        pcretest is linked with readline.
1120    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1121        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1122        moved outside it again, because FALSE and TRUE are already defined in AIX,
1123        but BOOL is not.
1125    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1126        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1128    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1129        hyphens) following file names and line numbers when outputting matching
1130        lines. This is not true; no spaces are inserted. I have also clarified the
1131        wording for the --colour (or --color) option.
1133    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1134        was not coloured; this is different to GNU grep, so I have changed it to be
1135        the same.
1137    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1138        each matching line was coloured. Now it goes on to look for further matches
1139        of any of the test patterns, which is the same behaviour as GNU grep.
1141    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1142        doesn't make sense to accept an empty string match in pcregrep, so I have
1143        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1144        seems to be how GNU grep behaves.
1146    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1147        start or after a newline", because the conditional assertion was not being
1148        correctly handled. The rule now is that both the assertion and what follows
1149        in the first alternative must satisfy the test.
1151    9.  If auto-callout was enabled in a pattern with a conditional group whose
1152        condition was an assertion, PCRE could crash during matching, both with
1153        pcre_exec() and pcre_dfa_exec().
1155    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1156        used for matching.
1158    11. Unicode property support in character classes was not working for
1159        characters (bytes) greater than 127 when not in UTF-8 mode.
1161    12. Added the -M command line option to pcretest.
1163    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1165    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1167    16. Added comments and documentation about mis-use of no_arg in the C++
1168        wrapper.
1170    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1171        from Martin Jerabek that uses macro names for all relevant character and
1172        string constants.
1174    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1175        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1176        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1177        these, but not everybody uses configure.
1179    19. A conditional group that had only one branch was not being correctly
1180        recognized as an item that could match an empty string. This meant that an
1181        enclosing group might also not be so recognized, causing infinite looping
1182        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1183        with the subject "ab", where knowledge that the repeated group can match
1184        nothing is needed in order to break the loop.
1186    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1187        exec(), but without supplying a callout function, matching went wrong.
1189    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1190        leak if the size of the offset vector was greater than 30. When the vector
1191        is smaller, the saved offsets during recursion go onto a local stack
1192        vector, but for larger vectors malloc() is used. It was failing to free
1193        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1194        error, in fact).
1196    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1197        heapframe that is used only when UTF-8 support is enabled. This caused no
1198        problem, but was untidy.
1200    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1201        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1202        included within another project.
1204    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1205        slightly modified by me:
1207          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1208              not building pcregrep.
1210          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1211              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1213    25. Forward references, both numeric and by name, in patterns that made use of
1214        duplicate group numbers, could behave incorrectly or give incorrect errors,
1215        because when scanning forward to find the reference group, PCRE was not
1216        taking into account the duplicate group numbers. A pattern such as
1217        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1219    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1220        the feature of a custom pointer more persuasive (as requested by a user).
1222    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1223        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1224        pre-defined.
1226    28. Added support for (*UTF8) at the start of a pattern.
1228    29. Arrange for flags added by the "release type" setting in CMake to be shown
1229        in the configuration summary.
1232    Version 7.8 05-Sep-08
1233    ---------------------
1235    1.  Replaced UCP searching code with optimized version as implemented for Ad
1236        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1237        stage table and inline lookup instead of a function, giving speed ups of 2
1238        to 5 times on some simple patterns that I tested. Permission was given to
1239        distribute the MultiStage2.py script that generates the tables (it's not in
1240        the tarball, but is in the Subversion repository).
1242    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1243        scripts.
1245    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1246        a group with a zero qualifier. The result of the study could be incorrect,
1247        or the function might crash, depending on the pattern.
1249    4.  Caseless matching was not working for non-ASCII characters in back
1250        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1251        It now works when Unicode Property Support is available.
1253    5.  In pcretest, an escape such as \x{de} in the data was always generating
1254        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1255        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1256        truncation.
1258    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1260    7.  Added two (int) casts to pcregrep when printing the difference of two
1261        pointers, in case they are 64-bit values.
1263    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1264        test 2 if it fails.
1266    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1267        and a #define of that name to empty if it is not externally set. This is to
1268        allow users of MSVC to set it if necessary.
1270    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1271        the convenience functions in the pcre_get.c source file.
1273    11. An option change at the start of a pattern that had top-level alternatives
1274        could cause overwriting and/or a crash. This command provoked a crash in
1275        some environments:
1277          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1279        This potential security problem was recorded as CVE-2008-2371.
1281    12. For a pattern where the match had to start at the beginning or immediately
1282        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1283        pcre_dfa_exec() could read past the end of the passed subject if there was
1284        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1285        pcretest so that it places the subject at the end of its malloc-ed buffer.
1287    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1288        exec() might read past the end of the data buffer in UTF-8 mode.
1290    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1291        the data contained the byte 0x85 as part of a UTF-8 character within its
1292        first line. This applied both to normal and DFA matching.
1294    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1295        /^[^d]*?$/8 failed to match "abc".
1297    16. Added a missing copyright notice to pcrecpp_internal.h.
1299    17. Make it more clear in the documentation that values returned from
1300        pcre_exec() in ovector are byte offsets, not character counts.
1302    18. Tidied a few places to stop certain compilers from issuing warnings.
1304    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1305        supplied by Stefan Weber. I made a further small update for 7.8 because
1306        there is a change of source arrangements: the pcre_searchfuncs.c module is
1307        replaced by pcre_ucd.c.
1310    Version 7.7 07-May-08
1311    ---------------------
1313    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1314        a string to a long long, pretend we don't even have a long long." This is
1315        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1317    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1318        pre-7.6 versions, which defined a global no_arg variable instead of putting
1319        it in the RE class. (See also #8 below.)
1321    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1322        Lopes.
1324    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1326        (1) The include/exclude patterns were being applied to the whole pathnames
1327            of files, instead of just to the final components.
1329        (2) If there was more than one level of directory, the subdirectories were
1330            skipped unless they satisfied the include/exclude conditions. This is
1331            inconsistent with GNU grep (and could even be seen as contrary to the
1332            pcregrep specification - which I improved to make it absolutely clear).
1333            The action now is always to scan all levels of directory, and just
1334            apply the include/exclude patterns to regular files.
1336    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1337        --exclude_dir in the tests to avoid scanning .svn directories.
1339    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1340        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1341        doesn't support NULs in patterns.
1343    7.  Added some missing "const"s to declarations of static tables in
1344        pcre_compile.c and pcre_dfa_exec.c.
1346    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1347        caused by fix #2  above. (Subsequently also a second patch to fix the
1348        first patch. And a third patch - this was a messy problem.)
1350    9.  Applied Craig's patch to remove the use of push_back().
1352    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1353        matching function regexec().
1355    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1356        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1357        references. PCRE supports relative numbers with this syntax (I don't think
1358        Oniguruma does).
1360    12. Previously, a group with a zero repeat such as (...){0} was completely
1361        omitted from the compiled regex. However, this means that if the group
1362        was called as a subroutine from elsewhere in the pattern, things went wrong
1363        (an internal error was given). Such groups are now left in the compiled
1364        pattern, with a new opcode that causes them to be skipped at execution
1365        time.
1367    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1368        to the way PCRE behaves:
1370        (a) A lone ] character is dis-allowed (Perl treats it as data).
1372        (b) A back reference to an unmatched subpattern matches an empty string
1373            (Perl fails the current match path).
1375        (c) A data ] in a character class must be notated as \] because if the
1376            first data character in a class is ], it defines an empty class. (In
1377            Perl it is not possible to have an empty class.) The empty class []
1378            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1379            The negative empty class [^] matches any one character, independently
1380            of the DOTALL setting.
1382    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1383        non-existent subpattern following a character class starting with ']' and
1384        containing () gave an internal compiling error instead of "reference to
1385        non-existent subpattern". Fortunately, when the pattern did exist, the
1386        compiled code was correct. (When scanning forwards to check for the
1387        existencd of the subpattern, it was treating the data ']' as terminating
1388        the class, so got the count wrong. When actually compiling, the reference
1389        was subsequently set up correctly.)
1391    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1392        it was being rejected as not supported by pcre_dfa_exec(), even though
1393        other assertions are supported. I have made pcre_dfa_exec() support
1394        (*FAIL).
1396    16. The implementation of 13c above involved the invention of a new opcode,
1397        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1398        cannot be changed at match time, I realized I could make a small
1399        improvement to matching performance by compiling OP_ALLANY instead of
1400        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1401        on the OP_ANY path.
1403    17. Compiling pcretest on Windows with readline support failed without the
1404        following two fixes: (1) Make the unistd.h include conditional on
1405        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1407    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1408        ncurses library to be included for pcretest when ReadLine support is
1409        requested, but also to allow for it to be overridden. This patch came from
1410        Daniel Bergström.
1412    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1413        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1414        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1415        spotting this.
1418    Version 7.6 28-Jan-08
1419    ---------------------
1421    1.  A character class containing a very large number of characters with
1422        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1423        overflow.
1425    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1426        HAVE_LONG_LONG is not defined.
1428    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1429        bring them up to date and include new features. This patch includes:
1431        - Fixed PH's badly added libz and libbz2 support.
1432        - Fixed a problem with static linking.
1433        - Added pcredemo. [But later removed - see 7 below.]
1434        - Fixed dftables problem and added an option.
1435        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1436            HAVE_LONG_LONG.
1437        - Added readline support for pcretest.
1438        - Added an listing of the option settings after cmake has run.
1440    4.  A user submitted a patch to Makefile that makes it easy to create
1441        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1442        Makefile.am that cause it to include this special target, without
1443        affecting anything else. Note that the same mingw target plus all
1444        the other distribution libraries and programs are now supported
1445        when configuring with CMake (see 6 below) instead of with
1446        Configure/Make.
1448    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1449        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1450        exported in the Windows port". It has not yet been confirmed that the patch
1451        solves the problem, but it does no harm.
1453    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1454        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1455        with CMake, and also correct the comment about stack recursion.
1457    7.  Remove the automatic building of pcredemo from the ./configure system and
1458        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1459        of a program that users should build themselves after PCRE is installed, so
1460        building it automatically is not really right. What is more, it gave
1461        trouble in some build environments.
1463    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1466    Version 7.5 10-Jan-08
1467    ---------------------
1469    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1470        values in parens when parsing an RE using the C++ wrapper."
1472    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1473        Characters greater than 255 were excluded from the class instead of being
1474        included.
1476    3.  The same bug as (2) above applied to negated POSIX classes such as
1477        [:^space:].
1479    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1480        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1481        I have changed it.
1483    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1484        first named subpattern) and a construct such as (?&a) would reference the
1485        first named subpattern whose name started with "a" (in other words, the
1486        length check was missing). Both these problems are fixed. "Subpattern name
1487        expected" is now given for (?&) (a zero-length name), and this patch also
1488        makes it give the same error for \k'' (previously it complained that that
1489        was a reference to a non-existent subpattern).
1491    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1492        this is right because (?- can be followed by option settings as well as by
1493        digits. I have, however, made the messages clearer.
1495    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1496        than the number used in the conditional) now cause a compile-time error.
1497        This is actually not compatible with Perl, which accepts such patterns, but
1498        treats the conditional as always being FALSE (as PCRE used to), but it
1499        seems to me that giving a diagnostic is better.
1501    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1502        and messages.
1504    9.  Fix two occurrences of "backslash" in comments that should have been
1505        "backspace".
1507    10. Remove two redundant lines of code that can never be obeyed (their function
1508        was moved elsewhere).
1510    11. The program that makes PCRE's Unicode character property table had a bug
1511        which caused it to generate incorrect table entries for sequences of
1512        characters that have the same character type, but are in different scripts.
1513        It amalgamated them into a single range, with the script of the first of
1514        them. In other words, some characters were in the wrong script. There were
1515        thirteen such cases, affecting characters in the following ranges:
1517          U+002b0 - U+002c1
1518          U+0060c - U+0060d
1519          U+0061e - U+00612
1520          U+0064b - U+0065e
1521          U+0074d - U+0076d
1522          U+01800 - U+01805
1523          U+01d00 - U+01d77
1524          U+01d9b - U+01dbf
1525          U+0200b - U+0200f
1526          U+030fc - U+030fe
1527          U+03260 - U+0327f
1528          U+0fb46 - U+0fbb1
1529          U+10450 - U+1049d
1531    12. The -o option (show only the matching part of a line) for pcregrep was not
1532        compatible with GNU grep in that, if there was more than one match in a
1533        line, it showed only the first of them. It now behaves in the same way as
1534        GNU grep.
1536    13. If the -o and -v options were combined for pcregrep, it printed a blank
1537        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1538        does the same. The return code can be used to tell if there were any
1539        non-matching lines.
1541    14. Added --file-offsets and --line-offsets to pcregrep.
1543    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1544        infinitely looping recursion. The bug was that positive lookaheads were not
1545        being skipped when checking for a possible empty match (negative lookaheads
1546        and both kinds of lookbehind were skipped).
1548    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1549        inclusion of <windows.h> to before rather than after the definition of
1550        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1552    17. Specifying a possessive quantifier with a specific limit for a Unicode
1553        character property caused pcre_compile() to compile bad code, which led at
1554        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1555        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1556        caused the error; without that there was no problem.
1558    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1560    19. Added --enable-pcretest-libreadline.
1562    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1563        RE::GlobalReplace(). As a result, the number of replacements returned was
1564        double what it should be. I removed one of the increments, but Craig sent a
1565        later patch that removed the other one (the right fix) and added unit tests
1566        that check the return values (which was not done before).
1568    21. Several CMake things:
1570        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1571            the names libpcre and libpcreposix, not just pcre and pcreposix.
1573        (2) The above change means that pcretest and pcregrep are now correctly
1574            linked with the newly-built libraries, not previously installed ones.
1578    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1579        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1580        UTF-8 newline character). The key issue is that the pattern starts .*;
1581        this means that the match must be either at the beginning, or after a
1582        newline. The bug was in the code for advancing after a failed match and
1583        checking that the new position followed a newline. It was not taking
1584        account of UTF-8 characters correctly.
1586    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1587        character classes. PCRE was not treating the sequence [:...:] as a
1588        character class unless the ... were all letters. Perl, however, seems to
1589        allow any characters between [: and :], though of course it rejects as
1590        unknown any "names" that contain non-letters, because all the known class
1591        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1592        for example, whereas PCRE did not - it did not recognize a POSIX character
1593        class. This seemed a bit dangerous, so the code has been changed to be
1594        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1595        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1596        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1597        Perl does, and where it didn't before.
1599    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1600        Windows environments %n is disabled by default.
1603    Version 7.4 21-Sep-07
1604    ---------------------
1606    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1607        means that a class such as [\s] counted as "explicit reference to CR or
1608        LF". That isn't really right - the whole point of the change was to try to
1609        help when there was an actual mention of one of the two characters. So now
1610        the change happens only if \r or \n (or a literal CR or LF) character is
1611        encountered.
1613    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1614        of both had grown to the point where there were only 3 bits left.
1615        Fortunately, there was spare space in the data structure, and so I have
1616        moved the internal flags into a new 16-bit field to free up more option
1617        bits.
1619    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1620        but did not set the internal JCHANGED flag - either of these is enough to
1621        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1622        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1623        start sets both bits.
1625    4.  Added options (at build time, compile time, exec time) to change \R from
1626        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1628    5.  doc/pcresyntax.html was missing from the distribution.
1630    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1631        compatibility, even though it is no longer used.
1633    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1634        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1635        windows.h file is present (where different names are used). [This was
1636        reversed later after testing - see 16 below.]
1638    8.  Changed all #include <config.h> to #include "config.h". There were also
1639        some further <pcre.h> cases that I changed to "pcre.h".
1641    9.  When pcregrep was used with the --colour option, it missed the line ending
1642        sequence off the lines that it output.
1644    10. It was pointed out to me that arrays of string pointers cause lots of
1645        relocations when a shared library is dynamically loaded. A technique of
1646        using a single long string with a table of offsets can drastically reduce
1647        these. I have refactored PCRE in four places to do this. The result is
1648        dramatic:
1650          Originally:                          290
1651          After changing UCP table:            187
1652          After changing error message table:   43
1653          After changing table of "verbs"       36
1654          After changing table of Posix names   22
1656        Thanks to the folks working on Gregex for glib for this insight.
1658    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1659        unicode-properties was also set.
1661    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1663    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1664        checked only for CRLF.
1666    14. Added casts to pcretest.c to avoid compiler warnings.
1668    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1670    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1671        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1672        entirely. This removes changes made in 7 above.
1674    17. The CMake files have been updated, and there is now more information about
1675        building with CMake in the NON-UNIX-USE document.
1678    Version 7.3 28-Aug-07
1679  ---------------------  ---------------------
1681   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 64  Version 7.3 05-Jul-07 Line 1738  Version 7.3 05-Jul-07
1738      dynamic way, which I have now done. The artificial limitation on group      dynamic way, which I have now done. The artificial limitation on group
1739      length has been removed - we now have only the limit on the total length of      length has been removed - we now have only the limit on the total length of
1740      the compiled pattern, which depends on the LINK_SIZE setting.      the compiled pattern, which depends on the LINK_SIZE setting.
1742  10. Fixed a bug in the documentation for get/copy named substring when  10. Fixed a bug in the documentation for get/copy named substring when
1743      duplicate names are permitted. If none of the named substrings are set, the      duplicate names are permitted. If none of the named substrings are set, the
1744      functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an      functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1745      empty string.      empty string.
1747    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1748        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1749        because the ] is interpreted as the first data character and the
1750        terminating ] is not found. PCRE has been made compatible with Perl in this
1751        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1752        cause memory overwriting.
1754    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1755        string has been matched (to stop an infinite loop). It was not recognizing
1756        a conditional subpattern that could match an empty string if that
1757        subpattern was within another subpattern. For example, it looped when
1758        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1759        condition was not nested. This bug has been fixed.
1761    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1762        past the start of the subject in the presence of bytes with the top bit
1763        set, for example "\x8aBCD".
1765    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1766        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1768    14. Optimized (?!) to (*FAIL).
1770    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1771        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1772        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1773        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1774        does: it's just the validity check that is more restrictive.
1776    16. Inserted checks for integer overflows during escape sequence (backslash)
1777        processing, and also fixed erroneous offset values for syntax errors during
1778        backslash processing.
1780    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1781        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1783    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1784        caused an overrun.
1786    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1787        something other than just ASCII characters) inside a group that had an
1788        unlimited repeat caused a loop at compile time (while checking to see
1789        whether the group could match an empty string).
1791    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1792        [\P{Any}] did so. (Error in the code for printing property names.)
1794    21. An orphan \E inside a character class could cause a crash.
1796    22. A repeated capturing bracket such as (A)? could cause a wild memory
1797        reference during compilation.
1799    23. There are several functions in pcre_compile() that scan along a compiled
1800        expression for various reasons (e.g. to see if it's fixed length for look
1801        behind). There were bugs in these functions when a repeated \p or \P was
1802        present in the pattern. These operators have additional parameters compared
1803        with \d, etc, and these were not being taken into account when moving along
1804        the compiled data. Specifically:
1806        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1807            length.
1809        (b) An item such as \pL+ within a repeated group could cause crashes or
1810            loops.
1812        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1813            "reference to non-existent subpattern" error.
1815        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1817    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1818        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1820    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1822    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1823        character were causing crashes (broken optimization).
1825    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1826        \p or \P) caused a compile-time loop.
1828    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1829        break. For example, the unstudied pattern [\r\n]A does not match the string
1830        "\r\nA" because change 7.0/46 below moves the current point on by two
1831        characters after failing to match at the start. However, the pattern \nA
1832        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1833        the same is true. There doesn't seem any very clean way out of this, but
1834        what I have chosen to do makes the common cases work: PCRE now takes note
1835        of whether there can be an explicit match for \r or \n anywhere in the
1836        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1837        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1838        pattern has explicit CR or LF references.
1840    29. Added (*CR) etc for changing newline setting at start of pattern.
1843  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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