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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.21 05-Dec-2011
5    ------------------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  (*MARK) settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". The
60        maximum number of forward references (including repeats) was limited by the
61        internal workspace, and dependent on the LINK_SIZE. The code has been
62        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
63        the default depends on LINK_SIZE. There is a new upper limit (for safety)
64        of around 200,000 forward references. While doing this, I also speeded up
65        the filling in of repeated forward references.
67    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
68        incorrectly expecting the subject to contain another "a" after the start.
70    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
71        in the match, the SKIP should be ignored. This was not happening; instead
72        the SKIP was being treated as NOMATCH. For patterns such as
73        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
74        tested.
76    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
77        now much more compatible with Perl, in particular in cases where the result
78        is a non-match for a non-anchored pattern. For example, if
79        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
80        "m", where previously it did not return a name. A side effect of this
81        change is that for partial matches, the last encountered mark name is
82        returned, as for non matches. A number of tests that were previously not
83        Perl-compatible have been moved into the Perl-compatible test files. The
84        refactoring has had the pleasing side effect of removing one argument from
85        the match() function, thus reducing its stack requirements.
87    19. If the /S+ option was used in pcretest to study a pattern using JIT,
88        subsequent uses of /S (without +) incorrectly behaved like /S+.
90    21. Retrieve executable code size support for the JIT compiler and fixing
91        some warnings.
93    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
94        not work when the shorter character appeared right at the end of the
95        subject string.
97    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
98        systems.
100    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
101        output it when the /M option is used in pcretest.
103    25. The CheckMan script was not being included in the distribution. Also, added
104        an explicit "perl" to run Perl scripts from the PrepareRelease script
105        because this is reportedly needed in Windows.
107    26. If study data was being save in a file and studying had not found a set of
108        "starts with" bytes for the pattern, the data written to the file (though
109        never used) was taken from uninitialized memory and so caused valgrind to
110        complain.
113    Version 8.20 21-Oct-2011
114    ------------------------
116    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
117        a POSIX class. After further experiments with Perl, which convinced me that
118        Perl has bugs and confusions, a closing square bracket is no longer allowed
119        in a POSIX name. This bug also affected patterns with classes that started
120        with full stops.
122    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
123        captured substring, but while checking the failing first alternative,
124        substring 1 is temporarily captured. If the output vector supplied to
125        pcre_exec() was not big enough for this capture, the yield of the function
126        was still zero ("insufficient space for captured substrings"). This cannot
127        be totally fixed without adding another stack variable, which seems a lot
128        of expense for a edge case. However, I have improved the situation in cases
129        such as /(a)(b)x|abc/ matched against "abc", where the return code
130        indicates that fewer than the maximum number of slots in the ovector have
131        been set.
133    3.  Related to (2) above: when there are more back references in a pattern than
134        slots in the output vector, pcre_exec() uses temporary memory during
135        matching, and copies in the captures as far as possible afterwards. It was
136        using the entire output vector, but this conflicts with the specification
137        that only 2/3 is used for passing back captured substrings. Now it uses
138        only the first 2/3, for compatibility. This is, of course, another edge
139        case.
141    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
142        main code base, and can be used by building with --enable-jit. When this is
143        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
144        runtime --no-jit option is given.
146    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
147        ovector, the return from the function was zero, implying that there were
148        other matches that did not fit. The correct "exactly full" value is now
149        returned.
151    6.  If a subpattern that was called recursively or as a subroutine contained
152        (*PRUNE) or any other control that caused it to give a non-standard return,
153        invalid errors such as "Error -26 (nested recursion at the same subject
154        position)" or even infinite loops could occur.
156    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
157        computing the minimum length on reaching *ACCEPT, and so ended up with the
158        wrong value of 1 rather than 0. Further investigation indicates that
159        computing a minimum subject length in the presence of *ACCEPT is difficult
160        (think back references, subroutine calls), and so I have changed the code
161        so that no minimum is registered for a pattern that contains *ACCEPT.
163    8.  If (*THEN) was present in the first (true) branch of a conditional group,
164        it was not handled as intended. [But see 16 below.]
166    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
167        Sheri Pierce.
169    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
170        the first byte in a match must be "a".
172    11. Change 17 for 8.13 increased the recursion depth for patterns like
173        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
174        pattern contains any instances of (*THEN). If it does not, the old
175        optimizations are restored. It would be nice to do this on a per-group
176        basis, but at the moment that is not feasible.
178    12. In some environments, the output of pcretest -C is CRLF terminated. This
179        broke RunTest's code that checks for the link size. A single white space
180        character after the value is now allowed for.
182    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
183        For "fr", it uses the Windows-specific input and output files.
185    14. If (*THEN) appeared in a group that was called recursively or as a
186        subroutine, it did not work as intended. [But see next item.]
188    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
189        pattern fragments (but not containing any | characters). If A and B are
190        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
191        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
192        D. In other words, Perl considers parentheses that do not contain any |
193        characters to be part of a surrounding alternative, whereas PCRE was
194        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
195        differently. PCRE now behaves in the same way as Perl, except in the case
196        of subroutine/recursion calls such as (?1) which have in any case always
197        been different (but PCRE had them first :-).
199    16. Related to 15 above: Perl does not treat the | in a conditional group as
200        creating alternatives. Such a group is treated in the same way as an
201        ordinary group without any | characters when processing (*THEN). PCRE has
202        been changed to match Perl's behaviour.
204    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
205        RunGrepTest script failed.
207    18. Change 22 for version 13 caused atomic groups to use more stack. This is
208        inevitable for groups that contain captures, but it can lead to a lot of
209        stack use in large patterns. The old behaviour has been restored for atomic
210        groups that do not contain any capturing parentheses.
212    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
213        suppress the check for a minimum subject length at run time. (If it was
214        given to pcre_exec() or pcre_dfa_exec() it did work.)
216    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
217        fail to work when decoding hex characters in data strings in EBCDIC
218        environments.
220    21. It appears that in at least one Mac OS environment, the isxdigit() function
221        is implemented as a macro that evaluates to its argument more than once,
222        contravening the C 90 Standard (I haven't checked a later standard). There
223        was an instance in pcretest which caused it to go wrong when processing
224        \x{...} escapes in subject strings. The has been rewritten to avoid using
225        things like p++ in the argument of isxdigit().
228    Version 8.13 16-Aug-2011
229    ------------------------
231    1.  The Unicode data tables have been updated to Unicode 6.0.0.
233    2.  Two minor typos in pcre_internal.h have been fixed.
235    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
236        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
237        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
239    4.  There were a number of related bugs in the code for matching backrefences
240        caselessly in UTF-8 mode when codes for the characters concerned were
241        different numbers of bytes. For example, U+023A and U+2C65 are an upper
242        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
243        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
244        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
245        2-byte code at the end of the subject (it thought there wasn't enough data
246        left).
248    5.  Comprehensive information about what went wrong is now returned by
249        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
250        as the output vector has at least 2 elements. The offset of the start of
251        the failing character and a reason code are placed in the vector.
253    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
254        now returned is for the first byte of the failing character, instead of the
255        last byte inspected. This is an incompatible change, but I hope it is small
256        enough not to be a problem. It makes the returned offset consistent with
257        pcre_exec() and pcre_dfa_exec().
259    7.  pcretest now gives a text phrase as well as the error number when
260        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
261        failure, the offset and reason code are output.
263    8.  When \R was used with a maximizing quantifier it failed to skip backwards
264        over a \r\n pair if the subsequent match failed. Instead, it just skipped
265        back over a single character (\n). This seems wrong (because it treated the
266        two characters as a single entity when going forwards), conflicts with the
267        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
268        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
269        has been changed.
271    9.  Some internal refactoring has changed the processing so that the handling
272        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
273        time (the PCRE_DOTALL option was changed this way some time ago: version
274        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
275        which was always a bit of a fudge. It also means that there is one less
276        argument for the match() function, which reduces its stack requirements
277        slightly. This change also fixes an incompatibility with Perl: the pattern
278        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
280    10. More internal refactoring has drastically reduced the number of recursive
281        calls to match() for possessively repeated groups such as (abc)++ when
282        using pcre_exec().
284    11. While implementing 10, a number of bugs in the handling of groups were
285        discovered and fixed:
287        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
288        (a|)*(?1) gave a compile-time internal error.
289        ((a|)+)+  did not notice that the outer group could match an empty string.
290        (^a|^)+   was not marked as anchored.
291        (.*a|.*)+ was not marked as matching at start or after a newline.
293    12. Yet more internal refactoring has removed another argument from the match()
294        function. Special calls to this function are now indicated by setting a
295        value in a variable in the "match data" data block.
297    13. Be more explicit in pcre_study() instead of relying on "default" for
298        opcodes that mean there is no starting character; this means that when new
299        ones are added and accidentally left out of pcre_study(), testing should
300        pick them up.
302    14. The -s option of pcretest has been documented for ages as being an old
303        synonym of -m (show memory usage). I have changed it to mean "force study
304        for every regex", that is, assume /S for every regex. This is similar to -i
305        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
306        using it. It makes it easier to run collections of tests with and without
307        study enabled, and thereby test pcre_study() more easily. All the standard
308        tests are now run with and without -s (but some patterns can be marked as
309        "never study" - see 20 below).
311    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
312        restoration of the capturing data to the outer values was not happening
313        correctly.
315    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
316        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
317        pattern had matched an empty string, and so incorrectly returned a no
318        match.
320    17. There was optimizing code for the last branch of non-capturing parentheses,
321        and also for the obeyed branch of a conditional subexpression, which used
322        tail recursion to cut down on stack usage. Unfortunately, now that there is
323        the possibility of (*THEN) occurring in these branches, tail recursion is
324        no longer possible because the return has to be checked for (*THEN). These
325        two optimizations have therefore been removed. [But see 8.20/11 above.]
327    18. If a pattern containing \R was studied, it was assumed that \R always
328        matched two bytes, thus causing the minimum subject length to be
329        incorrectly computed because \R can also match just one byte.
331    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
332        was incorrectly computed.
334    20. If /S is present twice on a test pattern in pcretest input, it now
335        *disables* studying, thereby overriding the use of -s on the command line
336        (see 14 above). This is necessary for one or two tests to keep the output
337        identical in both cases.
339    21. When (*ACCEPT) was used in an assertion that matched an empty string and
340        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
342    22. When an atomic group that contained a capturing parenthesis was
343        successfully matched, but the branch in which it appeared failed, the
344        capturing was not being forgotten if a higher numbered group was later
345        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
346        group 1 to "a", when in fact it should be unset. This applied to multi-
347        branched capturing and non-capturing groups, repeated or not, and also to
348        positive assertions (capturing in negative assertions does not happen
349        in PCRE) and also to nested atomic groups.
351    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
352        subject after a captured substring, to make it easier to tell which of a
353        number of identical substrings has been captured.
355    24. The way atomic groups are processed by pcre_exec() has been changed so that
356        if they are repeated, backtracking one repetition now resets captured
357        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
358        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
359        "aaa". Previously, it would have been "a". As part of this code
360        refactoring, the way recursive calls are handled has also been changed.
362    25. If an assertion condition captured any substrings, they were not passed
363        back unless some other capturing happened later. For example, if
364        (?(?=(a))a) was matched against "a", no capturing was returned.
366    26. When studying a pattern that contained subroutine calls or assertions,
367        the code for finding the minimum length of a possible match was handling
368        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
369        group 1 called group 2 while simultaneously a separate group 2 called group
370        1). A stack overflow occurred in this case. I have fixed this by limiting
371        the recursion depth to 10.
373    27. Updated RunTest.bat in the distribution to the version supplied by Tom
374        Fortmann. This supports explicit test numbers on the command line, and has
375        argument validation and error reporting.
377    28. An instance of \X with an unlimited repeat could fail if at any point the
378        first character it looked at was a mark character.
380    29. Some minor code refactoring concerning Unicode properties and scripts
381        should reduce the stack requirement of match() slightly.
383    30. Added the '=' option to pcretest to check the setting of unused capturing
384        slots at the end of the pattern, which are documented as being -1, but are
385        not included in the return count.
387    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
388        compiled something random. Now it gives a compile-time error (as does
389        Perl).
391    32. A *MARK encountered during the processing of a positive assertion is now
392        recorded and passed back (compatible with Perl).
394    33. If --only-matching or --colour was set on a pcregrep call whose pattern
395        had alternative anchored branches, the search for a second match in a line
396        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
397        matched the line "0102" twice. The same bug affected patterns that started
398        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
399        twice.
401    34. Previously, PCRE did not allow quantification of assertions. However, Perl
402        does, and because of capturing effects, quantifying parenthesized
403        assertions may at times be useful. Quantifiers are now allowed for
404        parenthesized assertions.
406    35. A minor code tidy in pcre_compile() when checking options for \R usage.
408    36. \g was being checked for fancy things in a character class, when it should
409        just be a literal "g".
411    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
412        appearance of a nested POSIX class supersedes an apparent external class.
413        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
414        unescaped square brackets may also appear as part of class names. For
415        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
416        more like Perl. (But see 8.20/1 above.)
418    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
419        was because it thought it was \N{name}, which is not supported).
421    39. Add minix to OS list not supporting the -S option in pcretest.
423    40. PCRE tries to detect cases of infinite recursion at compile time, but it
424        cannot analyze patterns in sufficient detail to catch mutual recursions
425        such as ((?1))((?2)). There is now a runtime test that gives an error if a
426        subgroup is called recursively as a subpattern for a second time at the
427        same position in the subject string. In previous releases this might have
428        been caught by the recursion limit, or it might have run out of stack.
430    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
431        happen only once. PCRE was, however incorrectly giving a compile time error
432        "recursive call could loop indefinitely" because it cannot analyze the
433        pattern in sufficient detail. The compile time test no longer happens when
434        PCRE is compiling a conditional subpattern, but actual runaway loops are
435        now caught at runtime (see 40 above).
437    42. It seems that Perl allows any characters other than a closing parenthesis
438        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
439        has been changed to be the same.
441    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
442        as not to get warnings when autogen.sh is called. Also changed
443        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
445    44. To help people who use pcregrep to scan files containing exceedingly long
446        lines, the following changes have been made:
448        (a) The default value of the buffer size parameter has been increased from
449            8K to 20K. (The actual buffer used is three times this size.)
451        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
452            PCRE is built.
454        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
455            to be set at run time.
457        (d) Numerical values in pcregrep options can be followed by K or M, for
458            example --buffer-size=50K.
460        (e) If a line being scanned overflows pcregrep's buffer, an error is now
461            given and the return code is set to 2.
463    45. Add a pointer to the latest mark to the callout data block.
465    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
466        partial match of an empty string instead of no match. This was specific to
467        the use of ".".
469    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
470        complete match instead of a partial match. This bug was dependent on both
471        the PCRE_UTF8 and PCRE_DOTALL options being set.
473    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
474        starting byte set, because \b was not being ignored.
477    Version 8.12 15-Jan-2011
478    ------------------------
480    1.  Fixed some typos in the markup of the man pages, and wrote a script that
481        checks for such things as part of the documentation building process.
483    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
484        --match-limit and --recursion-limit options (added for 8.11). In
485        particular, this made one of the standard tests fail. (The integer value
486        went into the wrong half of a long int.)
488    3.  If the --colour option was given to pcregrep with -v (invert match), it
489        did strange things, either producing crazy output, or crashing. It should,
490        of course, ignore a request for colour when reporting lines that do not
491        match.
493    4.  Another pcregrep bug caused similar problems if --colour was specified with
494        -M (multiline) and the pattern match finished with a line ending.
496    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
497        matched in multiline mode, the following line was shown as part of the
498        match. This seems wrong, so I have changed it.
500    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
501        the check for further matches in the same line (so they could be coloured)
502        to overrun the end of the current line. If another match was found, it was
503        incorrectly shown (and then shown again when found in the next line).
505    7.  If pcregrep was compiled under Windows, there was a reference to the
506        function pcregrep_exit() before it was defined. I am assuming this was
507        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
508        reported by a user. I've moved the definition above the reference.
511    Version 8.11 10-Dec-2010
512    ------------------------
514    1.  (*THEN) was not working properly if there were untried alternatives prior
515        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
516        backtracked to try for "b" instead of moving to the next alternative branch
517        at the same level (in this case, to look for "c"). The Perl documentation
518        is clear that when (*THEN) is backtracked onto, it goes to the "next
519        alternative in the innermost enclosing group".
521    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
522        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
523        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
524        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
525        (*THEN).
527    3.  If \s appeared in a character class, it removed the VT character from
528        the class, even if it had been included by some previous item, for example
529        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
530        of \s, but is part of the POSIX "space" class.)
532    4.  A partial match never returns an empty string (because you can always
533        match an empty string at the end of the subject); however the checking for
534        an empty string was starting at the "start of match" point. This has been
535        changed to the "earliest inspected character" point, because the returned
536        data for a partial match starts at this character. This means that, for
537        example, /(?<=abc)def/ gives a partial match for the subject "abc"
538        (previously it gave "no match").
540    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
541        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
542        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
543        has an implication that the given string is incomplete (because a partial
544        match is preferred over a full match). For this reason, these items now
545        give a partial match in this situation. [Aside: previously, the one case
546        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
547        match rather than a full match, which was wrong by the old rules, but is
548        now correct.]
550    6.  There was a bug in the handling of #-introduced comments, recognized when
551        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
552        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
553        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
554        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
555        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
556        places in pcre_compile().
558    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
559        comments when looking ahead for named forward references to subpatterns,
560        the only newline sequence it recognized was NL. It now handles newlines
561        according to the set newline convention.
563    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
564        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
565        cater for a lack of strerror(). These oversights have been fixed.
567    9.  Added --match-limit and --recursion-limit to pcregrep.
569    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
571    11. When the -o option was used, pcregrep was setting a return code of 1, even
572        when matches were found, and --line-buffered was not being honoured.
574    12. Added an optional parentheses number to the -o and --only-matching options
575        of pcregrep.
577    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
578        can match an empty string. The code to do it in pcretest and pcredemo
579        needed fixing:
581        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
582            only one byte after an empty string match just before CRLF (this case
583            just got forgotten; "any" and "anycrlf" were OK).
585        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
586            mode when an empty string match preceded an ASCII character followed by
587            a non-ASCII character. (The code for advancing by one character rather
588            than one byte was nonsense.)
590        (c) The pcredemo.c sample program did not have any code at all to handle
591            the cases when CRLF is a valid newline sequence.
593    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
594        as a starting offset was within the subject string. There is now a new
595        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
596        negative or greater than the length of the string. In order to test this,
597        pcretest is extended to allow the setting of negative starting offsets.
599    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
600        starting offset points to the beginning of a UTF-8 character was
601        unnecessarily clumsy. I tidied it up.
603    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
604        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
606    17. Nobody had reported that the --include_dir option, which was added in
607        release 7.7 should have been called --include-dir (hyphen, not underscore)
608        for compatibility with GNU grep. I have changed it to --include-dir, but
609        left --include_dir as an undocumented synonym, and the same for
610        --exclude-dir, though that is not available in GNU grep, at least as of
611        release 2.5.4.
613    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
614        characters from a string of bytes) have been redefined so as not to use
615        loops, in order to improve performance in some environments. At the same
616        time, I abstracted some of the common code into auxiliary macros to save
617        repetition (this should not affect the compiled code).
619    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
620        compile-time error is now given if \c is not followed by an ASCII
621        character, that is, a byte less than 128. (In EBCDIC mode, the code is
622        different, and any byte value is allowed.)
624    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
625        START_OPTIMIZE option, which is now allowed at compile time - but just
626        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
627        to pcregrep and other applications that have no direct access to PCRE
628        options. The new /Y option in pcretest sets this option when calling
629        pcre_compile().
631    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
632        back references. Groups containing recursive back references were forced to
633        be atomic by that change, but in the case of named groups, the amount of
634        memory required was incorrectly computed, leading to "Failed: internal
635        error: code overflow". This has been fixed.
637    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
638        pcretest.c, to avoid build problems in some Borland environments.
641    Version 8.10 25-Jun-2010
642    ------------------------
644    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
645        THEN.
647    2.  (*ACCEPT) was not working when inside an atomic group.
649    3.  Inside a character class, \B is treated as a literal by default, but
650        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
651        causes the error). The code is unchanged, but I tidied the documentation.
653    4.  Inside a character class, PCRE always treated \R and \X as literals,
654        whereas Perl faults them if its -w option is set. I have changed PCRE so
655        that it faults them when PCRE_EXTRA is set.
657    5.  Added support for \N, which always matches any character other than
658        newline. (It is the same as "." when PCRE_DOTALL is not set.)
660    6.  When compiling pcregrep with newer versions of gcc which may have
661        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
662        declared with attribute warn_unused_result" were given. Just casting the
663        result to (void) does not stop the warnings; a more elaborate fudge is
664        needed. I've used a macro to implement this.
666    7.  Minor change to pcretest.c to avoid a compiler warning.
668    8.  Added four artifical Unicode properties to help with an option to make
669        \s etc use properties (see next item). The new properties are: Xan
670        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
672    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
673        use Unicode properties. (*UCP) at the start of a pattern can be used to set
674        this option. Modified pcretest to add /W to test this facility. Added
675        REG_UCP to make it available via the POSIX interface.
677    10. Added --line-buffered to pcregrep.
679    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
680        studied, and the match started with a letter with a code point greater than
681        127 whose first byte was different to the first byte of the other case of
682        the letter, the other case of this starting letter was not recognized
683        (#976).
685    12. If a pattern that was studied started with a repeated Unicode property
686        test, for example, \p{Nd}+, there was the theoretical possibility of
687        setting up an incorrect bitmap of starting bytes, but fortunately it could
688        not have actually happened in practice until change 8 above was made (it
689        added property types that matched character-matching opcodes).
691    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
692        possible starting bytes for non-anchored patterns.
694    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
695        \R, and also a number of cases that involve Unicode properties, both
696        explicit and implicit when PCRE_UCP is set.
698    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
699        input, it could crash or give wrong results if characters with values
700        greater than 0xc0 were present in the subject string. (Detail: it assumed
701        UTF-8 input when processing these items.)
703    16. Added a lot of (int) casts to avoid compiler warnings in systems where
704        size_t is 64-bit (#991).
706    17. Added a check for running out of memory when PCRE is compiled with
707        --disable-stack-for-recursion (#990).
709    18. If the last data line in a file for pcretest does not have a newline on
710        the end, a newline was missing in the output.
712    19. The default pcre_chartables.c file recognizes only ASCII characters (values
713        less than 128) in its various bitmaps. However, there is a facility for
714        generating tables according to the current locale when PCRE is compiled. It
715        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
716        characters, are recognized by isspace() and therefore were getting set in
717        these tables, and indeed these tables seem to approximate to ISO 8859. This
718        caused a problem in UTF-8 mode when pcre_study() was used to create a list
719        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
720        which of course cannot start UTF-8 characters. I have changed the code so
721        that only real ASCII characters (less than 128) and the correct starting
722        bytes for UTF-8 encodings are set for characters greater than 127 when in
723        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
724        altogether.)
726    20. Added the /T option to pcretest so as to be able to run tests with non-
727        standard character tables, thus making it possible to include the tests
728        used for 19 above in the standard set of tests.
730    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
731        reference to a subpattern the other side of a comment that contains an
732        opening parenthesis caused either an internal compiling error, or a
733        reference to the wrong subpattern.
736    Version 8.02 19-Mar-2010
737    ------------------------
739    1.  The Unicode data tables have been updated to Unicode 5.2.0.
741    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
742        configured.
744    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
745        original author of that file, following a query about its status.
747    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
748        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
750    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
751        quantifier applied to a forward-referencing subroutine call, could compile
752        incorrect code or give the error "internal error: previously-checked
753        referenced subpattern not found".
755    6.  Both MS Visual Studio and Symbian OS have problems with initializing
756        variables to point to external functions. For these systems, therefore,
757        pcre_malloc etc. are now initialized to local functions that call the
758        relevant global functions.
760    7.  There were two entries missing in the vectors called coptable and poptable
761        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
762        I've fixed the data, and added a kludgy way of testing at compile time that
763        the lengths are correct (equal to the number of opcodes).
765    8.  Following on from 7, I added a similar kludge to check the length of the
766        eint vector in pcreposix.c.
768    9.  Error texts for pcre_compile() are held as one long string to avoid too
769        much relocation at load time. To find a text, the string is searched,
770        counting zeros. There was no check for running off the end of the string,
771        which could happen if a new error number was added without updating the
772        string.
774    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
776    11. \K was not working if it appeared in an atomic group or in a group that
777        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
778        \K is "not well defined" if used in an assertion. PCRE now accepts it if
779        the assertion is positive, but not if it is negative.
781    12. Change 11 fortuitously reduced the size of the stack frame used in the
782        "match()" function of pcre_exec.c by one pointer. Forthcoming
783        implementation of support for (*MARK) will need an extra pointer on the
784        stack; I have reserved it now, so that the stack frame size does not
785        decrease.
787    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
788        item in branch that calls a recursion is a subroutine call - as in the
789        second branch in the above example - was incorrectly given the compile-
790        time error "recursive call could loop indefinitely" because pcre_compile()
791        was not correctly checking the subroutine for matching a non-empty string.
793    14. The checks for overrunning compiling workspace could trigger after an
794        overrun had occurred. This is a "should never occur" error, but it can be
795        triggered by pathological patterns such as hundreds of nested parentheses.
796        The checks now trigger 100 bytes before the end of the workspace.
798    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
801    Version 8.01 19-Jan-2010
802    ------------------------
804    1.  If a pattern contained a conditional subpattern with only one branch (in
805        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
806        computed the wrong minimum data length (which is of course zero for such
807        subpatterns). This could cause incorrect "no match" results.
809    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
810        the pattern is reset in the first branch, pcre_compile() failed with
811        "internal error: code overflow at offset...". This happened only when
812        the reset was to the original external option setting. (An optimization
813        abstracts leading options settings into an external setting, which was the
814        cause of this.)
816    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
817        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
818        assertion pattern did not match (meaning that the assertion was true), it
819        was incorrectly treated as false if the SKIP had been reached during the
820        matching. This also applied to assertions used as conditions.
822    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
823        assertion subpattern, including such a pattern used as a condition,
824        unpredictable results occurred, instead of the error return
827    5.  The C++ GlobalReplace function was not working like Perl for the special
828        situation when an empty string is matched. It now does the fancy magic
829        stuff that is necessary.
831    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
832        removed. (These were left over from very, very early versions of PCRE.)
834    7.  Some cosmetic changes to the code to make life easier when compiling it
835        as part of something else:
837        (a) Change DEBUG to PCRE_DEBUG.
839        (b) In pcre_compile(), rename the member of the "branch_chain" structure
840            called "current" as "current_branch", to prevent a collision with the
841            Linux macro when compiled as a kernel module.
843        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
844            prevent a collision with the Linux macro when compiled as a kernel
845            module.
847    8.  In pcre_compile() there are some checks for integer overflows that used to
848        cast potentially large values to (double). This has been changed to that
849        when building, a check for int64_t is made, and if it is found, it is used
850        instead, thus avoiding the use of floating point arithmetic. (There is no
851        other use of FP in PCRE.) If int64_t is not found, the fallback is to
852        double.
854    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
855        2005 (difference between two addresses compared to an unsigned value).
857    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
858        custom one, because of the following reported problem in Windows:
860          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
861              under Win32.
862          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
863              therefore missing the function definition.
864          - The compiler thus generates a "C" signature for the test function.
865          - The linker fails to find the "C" function.
866          - PCRE fails to configure if asked to do so against libbz2.
868    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
869        messages were output:
871          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
872          rerunning libtoolize, to keep the correct libtool macros in-tree.
873          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
875        I have done both of these things.
877    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
878        most of the time, it *can* run out if it is given a pattern that contains a
879        runaway infinite recursion. I updated the discussion in the pcrestack man
880        page.
882    13. Now that we have gone to the x.xx style of version numbers, the minor
883        version may start with zero. Using 08 or 09 is a bad idea because users
884        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
885        interpreted as invalid octal numbers. I've updated the previous comment in
886        configure.ac, and also added a check that gives an error if 08 or 09 are
887        used.
889    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
890        causing partial matching to fail when the end of the subject matched \W
891        in a UTF-8 pattern where \W was quantified with a minimum of 3.
893    15. There were some discrepancies between the declarations in pcre_internal.h
894        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
895        their definitions. The declarations used "const uschar *" and the
896        definitions used USPTR. Even though USPTR is normally defined as "const
897        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
898        reported that: "This difference in casting confuses some C++ compilers, for
899        example, SunCC recognizes above declarations as different functions and
900        generates broken code for hbpcre." I have changed the declarations to use
901        USPTR.
903    16. GNU libtool is named differently on some systems. The autogen.sh script now
904        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
905        (FreeBSD).
907    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
908        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
909        comment: "Figure out how to create a longlong from a string: strtoll and
910        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
911        instance, but it only takes 2 args instead of 3!"
913    18. A subtle bug concerned with back references has been fixed by a change of
914        specification, with a corresponding code fix. A pattern such as
915        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
916        refers, was giving matches when it shouldn't. For example, xa=xaaa would
917        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
918        same bug. Such groups have to be quantified to be useful, or contained
919        inside another quantified group. (If there's no repetition, the reference
920        can never match.) The problem arises because, having left the group and
921        moved on to the rest of the pattern, a later failure that backtracks into
922        the group uses the captured value from the final iteration of the group
923        rather than the correct earlier one. I have fixed this in PCRE by forcing
924        any group that contains a reference to itself to be an atomic group; that
925        is, there cannot be any backtracking into it once it has completed. This is
926        similar to recursive and subroutine calls.
929    Version 8.00 19-Oct-09
930    ----------------------
932    1.  The table for translating pcre_compile() error codes into POSIX error codes
933        was out-of-date, and there was no check on the pcre_compile() error code
934        being within the table. This could lead to an OK return being given in
935        error.
937    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
938        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
939        in a Windows environment.
941    3.  The pcregrep --count option prints the count for each file even when it is
942        zero, as does GNU grep. However, pcregrep was also printing all files when
943        --files-with-matches was added. Now, when both options are given, it prints
944        counts only for those files that have at least one match. (GNU grep just
945        prints the file name in this circumstance, but including the count seems
946        more useful - otherwise, why use --count?) Also ensured that the
947        combination -clh just lists non-zero counts, with no names.
949    4.  The long form of the pcregrep -F option was incorrectly implemented as
950        --fixed_strings instead of --fixed-strings. This is an incompatible change,
951        but it seems right to fix it, and I didn't think it was worth preserving
952        the old behaviour.
954    5.  The command line items --regex=pattern and --regexp=pattern were not
955        recognized by pcregrep, which required --regex pattern or --regexp pattern
956        (with a space rather than an '='). The man page documented the '=' forms,
957        which are compatible with GNU grep; these now work.
959    6.  No libpcreposix.pc file was created for pkg-config; there was just
960        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
962    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
963        when UCP support is not needed, by modifying the Python script that
964        generates it from Unicode data files. This should not matter if the module
965        is correctly used as a library, but I received one complaint about 50K of
966        unwanted data. My guess is that the person linked everything into his
967        program rather than using a library. Anyway, it does no harm.
969    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
970        was a minimum greater than 1 for a wide character in a possessive
971        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
972        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
973        character. Chaos in the form of incorrect output or a compiling loop could
974        result.
976    9.  The restrictions on what a pattern can contain when partial matching is
977        requested for pcre_exec() have been removed. All patterns can now be
978        partially matched by this function. In addition, if there are at least two
979        slots in the offset vector, the offset of the earliest inspected character
980        for the match and the offset of the end of the subject are set in them when
981        PCRE_ERROR_PARTIAL is returned.
983    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
984        synonymous with PCRE_PARTIAL, for backwards compatibility, and
985        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
986        and may be more useful for multi-segment matching.
988    11. Partial matching with pcre_exec() is now more intuitive. A partial match
989        used to be given if ever the end of the subject was reached; now it is
990        given only if matching could not proceed because another character was
991        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
992        string "Z", which now yields "no match" instead of "partial match". In the
993        case of pcre_dfa_exec(), "no match" is given if every matching path for the
994        final character ended with (*FAIL).
996    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
997        if the pattern had a "must contain" character that was already found in the
998        earlier partial match, unless partial matching was again requested. For
999        example, with the pattern /dog.(body)?/, the "must contain" character is
1000        "g". If the first part-match was for the string "dog", restarting with
1001        "sbody" failed. This bug has been fixed.
1003    13. The string returned by pcre_dfa_exec() after a partial match has been
1004        changed so that it starts at the first inspected character rather than the
1005        first character of the match. This makes a difference only if the pattern
1006        starts with a lookbehind assertion or \b or \B (\K is not supported by
1007        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1008        matching functions compatible, and I think it's the right thing to do.
1010    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1011        so that the demonstration program is easily available in environments where
1012        PCRE has not been installed from source.
1014    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1015        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1016        library.
1018    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1019        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1020        is not the first non-POSIX option to be added. Clearly some people find
1021        these options useful.
1023    17. If a caller to the POSIX matching function regexec() passes a non-zero
1024        value for nmatch with a NULL value for pmatch, the value of
1025        nmatch is forced to zero.
1027    18. RunGrepTest did not have a test for the availability of the -u option of
1028        the diff command, as RunTest does. It now checks in the same way as
1029        RunTest, and also checks for the -b option.
1031    19. If an odd number of negated classes containing just a single character
1032        interposed, within parentheses, between a forward reference to a named
1033        subpattern and the definition of the subpattern, compilation crashed with
1034        an internal error, complaining that it could not find the referenced
1035        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1036        [The bug was that it was starting one character too far in when skipping
1037        over the character class, thus treating the ] as data rather than
1038        terminating the class. This meant it could skip too much.]
1040    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1041        /g option in pcretest when the pattern contains \K, which makes it possible
1042        to have an empty string match not at the start, even when the pattern is
1043        anchored. Updated pcretest and pcredemo to use this option.
1045    21. If the maximum number of capturing subpatterns in a recursion was greater
1046        than the maximum at the outer level, the higher number was returned, but
1047        with unset values at the outer level. The correct (outer level) value is
1048        now given.
1050    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1051        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1052        make it do so. The string so far is captured, making this feature
1053        compatible with Perl.
1055    23. The tests have been re-organized, adding tests 11 and 12, to make it
1056        possible to check the Perl 5.10 features against Perl 5.10.
1058    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1059        pattern matches a fixed length string. PCRE did not allow this; now it
1060        does. Neither allows recursion.
1062    25. I finally figured out how to implement a request to provide the minimum
1063        length of subject string that was needed in order to match a given pattern.
1064        (It was back references and recursion that I had previously got hung up
1065        on.) This code has now been added to pcre_study(); it finds a lower bound
1066        to the length of subject needed. It is not necessarily the greatest lower
1067        bound, but using it to avoid searching strings that are too short does give
1068        some useful speed-ups. The value is available to calling programs via
1069        pcre_fullinfo().
1071    26. While implementing 25, I discovered to my embarrassment that pcretest had
1072        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1073        study optimizations had never been tested with that matching function.
1074        Oops. What is worse, even when it was passed study data, there was a bug in
1075        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1076        were also very few tests of studied patterns with pcre_dfa_exec().
1078    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1079        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1080        on the other side of the coin, they are no longer allowed to have different
1081        names, because these cannot be distinguished in PCRE, and this has caused
1082        confusion. (This is a difference from Perl.)
1084    28. When duplicate subpattern names are present (necessarily with different
1085        numbers, as required by 27 above), and a test is made by name in a
1086        conditional pattern, either for a subpattern having been matched, or for
1087        recursion in such a pattern, all the associated numbered subpatterns are
1088        tested, and the overall condition is true if the condition is true for any
1089        one of them. This is the way Perl works, and is also more like the way
1090        testing by number works.
1093    Version 7.9 11-Apr-09
1094    ---------------------
1096    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1097        (pcretest), all targets were linked against these libraries. This included
1098        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1099        libraries. This caused unwanted dependencies to be created. This problem
1100        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1101        pcretest is linked with readline.
1103    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1104        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1105        moved outside it again, because FALSE and TRUE are already defined in AIX,
1106        but BOOL is not.
1108    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1109        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1111    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1112        hyphens) following file names and line numbers when outputting matching
1113        lines. This is not true; no spaces are inserted. I have also clarified the
1114        wording for the --colour (or --color) option.
1116    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1117        was not coloured; this is different to GNU grep, so I have changed it to be
1118        the same.
1120    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1121        each matching line was coloured. Now it goes on to look for further matches
1122        of any of the test patterns, which is the same behaviour as GNU grep.
1124    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1125        doesn't make sense to accept an empty string match in pcregrep, so I have
1126        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1127        seems to be how GNU grep behaves.
1129    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1130        start or after a newline", because the conditional assertion was not being
1131        correctly handled. The rule now is that both the assertion and what follows
1132        in the first alternative must satisfy the test.
1134    9.  If auto-callout was enabled in a pattern with a conditional group whose
1135        condition was an assertion, PCRE could crash during matching, both with
1136        pcre_exec() and pcre_dfa_exec().
1138    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1139        used for matching.
1141    11. Unicode property support in character classes was not working for
1142        characters (bytes) greater than 127 when not in UTF-8 mode.
1144    12. Added the -M command line option to pcretest.
1146    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1148    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1150    16. Added comments and documentation about mis-use of no_arg in the C++
1151        wrapper.
1153    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1154        from Martin Jerabek that uses macro names for all relevant character and
1155        string constants.
1157    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1158        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1159        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1160        these, but not everybody uses configure.
1162    19. A conditional group that had only one branch was not being correctly
1163        recognized as an item that could match an empty string. This meant that an
1164        enclosing group might also not be so recognized, causing infinite looping
1165        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1166        with the subject "ab", where knowledge that the repeated group can match
1167        nothing is needed in order to break the loop.
1169    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1170        exec(), but without supplying a callout function, matching went wrong.
1172    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1173        leak if the size of the offset vector was greater than 30. When the vector
1174        is smaller, the saved offsets during recursion go onto a local stack
1175        vector, but for larger vectors malloc() is used. It was failing to free
1176        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1177        error, in fact).
1179    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1180        heapframe that is used only when UTF-8 support is enabled. This caused no
1181        problem, but was untidy.
1183    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1184        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1185        included within another project.
1187    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1188        slightly modified by me:
1190          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1191              not building pcregrep.
1193          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1194              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1196    25. Forward references, both numeric and by name, in patterns that made use of
1197        duplicate group numbers, could behave incorrectly or give incorrect errors,
1198        because when scanning forward to find the reference group, PCRE was not
1199        taking into account the duplicate group numbers. A pattern such as
1200        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1202    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1203        the feature of a custom pointer more persuasive (as requested by a user).
1205    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1206        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1207        pre-defined.
1209    28. Added support for (*UTF8) at the start of a pattern.
1211    29. Arrange for flags added by the "release type" setting in CMake to be shown
1212        in the configuration summary.
1215    Version 7.8 05-Sep-08
1216    ---------------------
1218    1.  Replaced UCP searching code with optimized version as implemented for Ad
1219        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1220        stage table and inline lookup instead of a function, giving speed ups of 2
1221        to 5 times on some simple patterns that I tested. Permission was given to
1222        distribute the MultiStage2.py script that generates the tables (it's not in
1223        the tarball, but is in the Subversion repository).
1225    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1226        scripts.
1228    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1229        a group with a zero qualifier. The result of the study could be incorrect,
1230        or the function might crash, depending on the pattern.
1232    4.  Caseless matching was not working for non-ASCII characters in back
1233        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1234        It now works when Unicode Property Support is available.
1236    5.  In pcretest, an escape such as \x{de} in the data was always generating
1237        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1238        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1239        truncation.
1241    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1243    7.  Added two (int) casts to pcregrep when printing the difference of two
1244        pointers, in case they are 64-bit values.
1246    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1247        test 2 if it fails.
1249    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1250        and a #define of that name to empty if it is not externally set. This is to
1251        allow users of MSVC to set it if necessary.
1253    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1254        the convenience functions in the pcre_get.c source file.
1256    11. An option change at the start of a pattern that had top-level alternatives
1257        could cause overwriting and/or a crash. This command provoked a crash in
1258        some environments:
1260          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1262        This potential security problem was recorded as CVE-2008-2371.
1264    12. For a pattern where the match had to start at the beginning or immediately
1265        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1266        pcre_dfa_exec() could read past the end of the passed subject if there was
1267        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1268        pcretest so that it places the subject at the end of its malloc-ed buffer.
1270    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1271        exec() might read past the end of the data buffer in UTF-8 mode.
1273    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1274        the data contained the byte 0x85 as part of a UTF-8 character within its
1275        first line. This applied both to normal and DFA matching.
1277    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1278        /^[^d]*?$/8 failed to match "abc".
1280    16. Added a missing copyright notice to pcrecpp_internal.h.
1282    17. Make it more clear in the documentation that values returned from
1283        pcre_exec() in ovector are byte offsets, not character counts.
1285    18. Tidied a few places to stop certain compilers from issuing warnings.
1287    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1288        supplied by Stefan Weber. I made a further small update for 7.8 because
1289        there is a change of source arrangements: the pcre_searchfuncs.c module is
1290        replaced by pcre_ucd.c.
1293    Version 7.7 07-May-08
1294    ---------------------
1296    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1297        a string to a long long, pretend we don't even have a long long." This is
1298        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1300    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1301        pre-7.6 versions, which defined a global no_arg variable instead of putting
1302        it in the RE class. (See also #8 below.)
1304    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1305        Lopes.
1307    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1309        (1) The include/exclude patterns were being applied to the whole pathnames
1310            of files, instead of just to the final components.
1312        (2) If there was more than one level of directory, the subdirectories were
1313            skipped unless they satisfied the include/exclude conditions. This is
1314            inconsistent with GNU grep (and could even be seen as contrary to the
1315            pcregrep specification - which I improved to make it absolutely clear).
1316            The action now is always to scan all levels of directory, and just
1317            apply the include/exclude patterns to regular files.
1319    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1320        --exclude_dir in the tests to avoid scanning .svn directories.
1322    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1323        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1324        doesn't support NULs in patterns.
1326    7.  Added some missing "const"s to declarations of static tables in
1327        pcre_compile.c and pcre_dfa_exec.c.
1329    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1330        caused by fix #2  above. (Subsequently also a second patch to fix the
1331        first patch. And a third patch - this was a messy problem.)
1333    9.  Applied Craig's patch to remove the use of push_back().
1335    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1336        matching function regexec().
1338    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1339        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1340        references. PCRE supports relative numbers with this syntax (I don't think
1341        Oniguruma does).
1343    12. Previously, a group with a zero repeat such as (...){0} was completely
1344        omitted from the compiled regex. However, this means that if the group
1345        was called as a subroutine from elsewhere in the pattern, things went wrong
1346        (an internal error was given). Such groups are now left in the compiled
1347        pattern, with a new opcode that causes them to be skipped at execution
1348        time.
1350    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1351        to the way PCRE behaves:
1353        (a) A lone ] character is dis-allowed (Perl treats it as data).
1355        (b) A back reference to an unmatched subpattern matches an empty string
1356            (Perl fails the current match path).
1358        (c) A data ] in a character class must be notated as \] because if the
1359            first data character in a class is ], it defines an empty class. (In
1360            Perl it is not possible to have an empty class.) The empty class []
1361            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1362            The negative empty class [^] matches any one character, independently
1363            of the DOTALL setting.
1365    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1366        non-existent subpattern following a character class starting with ']' and
1367        containing () gave an internal compiling error instead of "reference to
1368        non-existent subpattern". Fortunately, when the pattern did exist, the
1369        compiled code was correct. (When scanning forwards to check for the
1370        existencd of the subpattern, it was treating the data ']' as terminating
1371        the class, so got the count wrong. When actually compiling, the reference
1372        was subsequently set up correctly.)
1374    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1375        it was being rejected as not supported by pcre_dfa_exec(), even though
1376        other assertions are supported. I have made pcre_dfa_exec() support
1377        (*FAIL).
1379    16. The implementation of 13c above involved the invention of a new opcode,
1380        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1381        cannot be changed at match time, I realized I could make a small
1382        improvement to matching performance by compiling OP_ALLANY instead of
1383        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1384        on the OP_ANY path.
1386    17. Compiling pcretest on Windows with readline support failed without the
1387        following two fixes: (1) Make the unistd.h include conditional on
1388        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1390    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1391        ncurses library to be included for pcretest when ReadLine support is
1392        requested, but also to allow for it to be overridden. This patch came from
1393        Daniel Bergström.
1395    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1396        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1397        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1398        spotting this.
1401    Version 7.6 28-Jan-08
1402    ---------------------
1404    1.  A character class containing a very large number of characters with
1405        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1406        overflow.
1408    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1409        HAVE_LONG_LONG is not defined.
1411    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1412        bring them up to date and include new features. This patch includes:
1414        - Fixed PH's badly added libz and libbz2 support.
1415        - Fixed a problem with static linking.
1416        - Added pcredemo. [But later removed - see 7 below.]
1417        - Fixed dftables problem and added an option.
1418        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1419            HAVE_LONG_LONG.
1420        - Added readline support for pcretest.
1421        - Added an listing of the option settings after cmake has run.
1423    4.  A user submitted a patch to Makefile that makes it easy to create
1424        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1425        Makefile.am that cause it to include this special target, without
1426        affecting anything else. Note that the same mingw target plus all
1427        the other distribution libraries and programs are now supported
1428        when configuring with CMake (see 6 below) instead of with
1429        Configure/Make.
1431    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1432        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1433        exported in the Windows port". It has not yet been confirmed that the patch
1434        solves the problem, but it does no harm.
1436    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1437        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1438        with CMake, and also correct the comment about stack recursion.
1440    7.  Remove the automatic building of pcredemo from the ./configure system and
1441        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1442        of a program that users should build themselves after PCRE is installed, so
1443        building it automatically is not really right. What is more, it gave
1444        trouble in some build environments.
1446    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1449    Version 7.5 10-Jan-08
1450    ---------------------
1452    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1453        values in parens when parsing an RE using the C++ wrapper."
1455    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1456        Characters greater than 255 were excluded from the class instead of being
1457        included.
1459    3.  The same bug as (2) above applied to negated POSIX classes such as
1460        [:^space:].
1462    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1463        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1464        I have changed it.
1466    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1467        first named subpattern) and a construct such as (?&a) would reference the
1468        first named subpattern whose name started with "a" (in other words, the
1469        length check was missing). Both these problems are fixed. "Subpattern name
1470        expected" is now given for (?&) (a zero-length name), and this patch also
1471        makes it give the same error for \k'' (previously it complained that that
1472        was a reference to a non-existent subpattern).
1474    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1475        this is right because (?- can be followed by option settings as well as by
1476        digits. I have, however, made the messages clearer.
1478    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1479        than the number used in the conditional) now cause a compile-time error.
1480        This is actually not compatible with Perl, which accepts such patterns, but
1481        treats the conditional as always being FALSE (as PCRE used to), but it
1482        seems to me that giving a diagnostic is better.
1484    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1485        and messages.
1487    9.  Fix two occurrences of "backslash" in comments that should have been
1488        "backspace".
1490    10. Remove two redundant lines of code that can never be obeyed (their function
1491        was moved elsewhere).
1493    11. The program that makes PCRE's Unicode character property table had a bug
1494        which caused it to generate incorrect table entries for sequences of
1495        characters that have the same character type, but are in different scripts.
1496        It amalgamated them into a single range, with the script of the first of
1497        them. In other words, some characters were in the wrong script. There were
1498        thirteen such cases, affecting characters in the following ranges:
1500          U+002b0 - U+002c1
1501          U+0060c - U+0060d
1502          U+0061e - U+00612
1503          U+0064b - U+0065e
1504          U+0074d - U+0076d
1505          U+01800 - U+01805
1506          U+01d00 - U+01d77
1507          U+01d9b - U+01dbf
1508          U+0200b - U+0200f
1509          U+030fc - U+030fe
1510          U+03260 - U+0327f
1511          U+0fb46 - U+0fbb1
1512          U+10450 - U+1049d
1514    12. The -o option (show only the matching part of a line) for pcregrep was not
1515        compatible with GNU grep in that, if there was more than one match in a
1516        line, it showed only the first of them. It now behaves in the same way as
1517        GNU grep.
1519    13. If the -o and -v options were combined for pcregrep, it printed a blank
1520        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1521        does the same. The return code can be used to tell if there were any
1522        non-matching lines.
1524    14. Added --file-offsets and --line-offsets to pcregrep.
1526    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1527        infinitely looping recursion. The bug was that positive lookaheads were not
1528        being skipped when checking for a possible empty match (negative lookaheads
1529        and both kinds of lookbehind were skipped).
1531    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1532        inclusion of <windows.h> to before rather than after the definition of
1533        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1535    17. Specifying a possessive quantifier with a specific limit for a Unicode
1536        character property caused pcre_compile() to compile bad code, which led at
1537        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1538        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1539        caused the error; without that there was no problem.
1541    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1543    19. Added --enable-pcretest-libreadline.
1545    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1546        RE::GlobalReplace(). As a result, the number of replacements returned was
1547        double what it should be. I removed one of the increments, but Craig sent a
1548        later patch that removed the other one (the right fix) and added unit tests
1549        that check the return values (which was not done before).
1551    21. Several CMake things:
1553        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1554            the names libpcre and libpcreposix, not just pcre and pcreposix.
1556        (2) The above change means that pcretest and pcregrep are now correctly
1557            linked with the newly-built libraries, not previously installed ones.
1561    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1562        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1563        UTF-8 newline character). The key issue is that the pattern starts .*;
1564        this means that the match must be either at the beginning, or after a
1565        newline. The bug was in the code for advancing after a failed match and
1566        checking that the new position followed a newline. It was not taking
1567        account of UTF-8 characters correctly.
1569    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1570        character classes. PCRE was not treating the sequence [:...:] as a
1571        character class unless the ... were all letters. Perl, however, seems to
1572        allow any characters between [: and :], though of course it rejects as
1573        unknown any "names" that contain non-letters, because all the known class
1574        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1575        for example, whereas PCRE did not - it did not recognize a POSIX character
1576        class. This seemed a bit dangerous, so the code has been changed to be
1577        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1578        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1579        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1580        Perl does, and where it didn't before.
1582    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1583        Windows environments %n is disabled by default.
1586    Version 7.4 21-Sep-07
1587    ---------------------
1589    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1590        means that a class such as [\s] counted as "explicit reference to CR or
1591        LF". That isn't really right - the whole point of the change was to try to
1592        help when there was an actual mention of one of the two characters. So now
1593        the change happens only if \r or \n (or a literal CR or LF) character is
1594        encountered.
1596    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1597        of both had grown to the point where there were only 3 bits left.
1598        Fortunately, there was spare space in the data structure, and so I have
1599        moved the internal flags into a new 16-bit field to free up more option
1600        bits.
1602    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1603        but did not set the internal JCHANGED flag - either of these is enough to
1604        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1605        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1606        start sets both bits.
1608    4.  Added options (at build time, compile time, exec time) to change \R from
1609        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1611    5.  doc/pcresyntax.html was missing from the distribution.
1613    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1614        compatibility, even though it is no longer used.
1616    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1617        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1618        windows.h file is present (where different names are used). [This was
1619        reversed later after testing - see 16 below.]
1621    8.  Changed all #include <config.h> to #include "config.h". There were also
1622        some further <pcre.h> cases that I changed to "pcre.h".
1624    9.  When pcregrep was used with the --colour option, it missed the line ending
1625        sequence off the lines that it output.
1627    10. It was pointed out to me that arrays of string pointers cause lots of
1628        relocations when a shared library is dynamically loaded. A technique of
1629        using a single long string with a table of offsets can drastically reduce
1630        these. I have refactored PCRE in four places to do this. The result is
1631        dramatic:
1633          Originally:                          290
1634          After changing UCP table:            187
1635          After changing error message table:   43
1636          After changing table of "verbs"       36
1637          After changing table of Posix names   22
1639        Thanks to the folks working on Gregex for glib for this insight.
1641    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1642        unicode-properties was also set.
1644    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1646    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1647        checked only for CRLF.
1649    14. Added casts to pcretest.c to avoid compiler warnings.
1651    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1653    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1654        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1655        entirely. This removes changes made in 7 above.
1657    17. The CMake files have been updated, and there is now more information about
1658        building with CMake in the NON-UNIX-USE document.
1661    Version 7.3 28-Aug-07
1662    ---------------------
1664     1. In the rejigging of the build system that eventually resulted in 7.1, the
1665        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1666        brackets there is not right, since it causes compilers to look for an
1667        installed pcre.h, not the version that is in the source that is being
1668        compiled (which of course may be different). I have changed it back to:
1670          #include "pcre.h"
1672        I have a vague recollection that the change was concerned with compiling in
1673        different directories, but in the new build system, that is taken care of
1674        by the VPATH setting the Makefile.
1676     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1677        when the subject happened to end in the byte 0x85 (e.g. if the last
1678        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1679        characters but of course it shouldn't be taken as a newline when it is part
1680        of another character. The bug was that, for an unlimited repeat of . in
1681        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1682        characters when looking for a newline.
1684     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1686     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1687        in debug output.
1689     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1690        long printing in the pcrecpp unittest when running under MinGW.
1692     6. ESC_K was left out of the EBCDIC table.
1694     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1695        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1696        limit also applies to "virtual nesting" when a pattern is recursive, and in
1697        this case 1000 isn't so big. I have been able to remove this limit at the
1698        expense of backing off one optimization in certain circumstances. Normally,
1699        when pcre_exec() would call its internal match() function recursively and
1700        immediately return the result unconditionally, it uses a "tail recursion"
1701        feature to save stack. However, when a subpattern that can match an empty
1702        string has an unlimited repetition quantifier, it no longer makes this
1703        optimization. That gives it a stack frame in which to save the data for
1704        checking that an empty string has been matched. Previously this was taken
1705        from the 1000-entry workspace that had been reserved. So now there is no
1706        explicit limit, but more stack is used.
1708     8. Applied Daniel's patches to solve problems with the import/export magic
1709        syntax that is required for Windows, and which was going wrong for the
1710        pcreposix and pcrecpp parts of the library. These were overlooked when this
1711        problem was solved for the main library.
1713     9. There were some crude static tests to avoid integer overflow when computing
1714        the size of patterns that contain repeated groups with explicit upper
1715        limits. As the maximum quantifier is 65535, the maximum group length was
1716        set at 30,000 so that the product of these two numbers did not overflow a
1717        32-bit integer. However, it turns out that people want to use groups that
1718        are longer than 30,000 bytes (though not repeat them that many times).
1719        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1720        made it possible to implement the integer overflow checks in a much more
1721        dynamic way, which I have now done. The artificial limitation on group
1722        length has been removed - we now have only the limit on the total length of
1723        the compiled pattern, which depends on the LINK_SIZE setting.
1725    10. Fixed a bug in the documentation for get/copy named substring when
1726        duplicate names are permitted. If none of the named substrings are set, the
1727        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1728        empty string.
1730    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1731        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1732        because the ] is interpreted as the first data character and the
1733        terminating ] is not found. PCRE has been made compatible with Perl in this
1734        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1735        cause memory overwriting.
1737    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1738        string has been matched (to stop an infinite loop). It was not recognizing
1739        a conditional subpattern that could match an empty string if that
1740        subpattern was within another subpattern. For example, it looped when
1741        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1742        condition was not nested. This bug has been fixed.
1744    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1745        past the start of the subject in the presence of bytes with the top bit
1746        set, for example "\x8aBCD".
1748    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1749        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1751    14. Optimized (?!) to (*FAIL).
1753    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1754        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1755        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1756        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1757        does: it's just the validity check that is more restrictive.
1759    16. Inserted checks for integer overflows during escape sequence (backslash)
1760        processing, and also fixed erroneous offset values for syntax errors during
1761        backslash processing.
1763    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1764        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1766    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1767        caused an overrun.
1769    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1770        something other than just ASCII characters) inside a group that had an
1771        unlimited repeat caused a loop at compile time (while checking to see
1772        whether the group could match an empty string).
1774    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1775        [\P{Any}] did so. (Error in the code for printing property names.)
1777    21. An orphan \E inside a character class could cause a crash.
1779    22. A repeated capturing bracket such as (A)? could cause a wild memory
1780        reference during compilation.
1782    23. There are several functions in pcre_compile() that scan along a compiled
1783        expression for various reasons (e.g. to see if it's fixed length for look
1784        behind). There were bugs in these functions when a repeated \p or \P was
1785        present in the pattern. These operators have additional parameters compared
1786        with \d, etc, and these were not being taken into account when moving along
1787        the compiled data. Specifically:
1789        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1790            length.
1792        (b) An item such as \pL+ within a repeated group could cause crashes or
1793            loops.
1795        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1796            "reference to non-existent subpattern" error.
1798        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1800    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1801        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1803    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1805    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1806        character were causing crashes (broken optimization).
1808    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1809        \p or \P) caused a compile-time loop.
1811    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1812        break. For example, the unstudied pattern [\r\n]A does not match the string
1813        "\r\nA" because change 7.0/46 below moves the current point on by two
1814        characters after failing to match at the start. However, the pattern \nA
1815        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1816        the same is true. There doesn't seem any very clean way out of this, but
1817        what I have chosen to do makes the common cases work: PCRE now takes note
1818        of whether there can be an explicit match for \r or \n anywhere in the
1819        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1820        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1821        pattern has explicit CR or LF references.
1823    29. Added (*CR) etc for changing newline setting at start of pattern.
1826    Version 7.2 19-Jun-07
1827    ---------------------
1829     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1830        which is apparently normally available under Windows.
1832     2. Re-jig the pcregrep tests with different newline settings in an attempt
1833        to make them independent of the local environment's newline setting.
1835     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1837     4. Some of the "internals" tests were previously cut out when the link size
1838        was not 2, because the output contained actual offsets. The recent new
1839        "Z" feature of pcretest means that these can be cut out, making the tests
1840        usable with all link sizes.
1842     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1843        stack recursion. This gives a massive performance boost under BSD, but just
1844        a small improvement under Linux. However, it saves one field in the frame
1845        in all cases.
1847     6. Added more features from the forthcoming Perl 5.10:
1849        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1850            recursion call. It refers to the nth most recently opened parentheses.
1852        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1853            to be opened parentheses.
1855        (c) Conditions that refer to capturing parentheses can be specified
1856            relatively, for example, (?(-2)... or (?(+3)...
1858        (d) \K resets the start of the current match so that everything before
1859            is not part of it.
1861        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1863        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1864            reference syntax.
1866        (g) (?| introduces a group in which the numbering of parentheses in each
1867            alternative starts with the same number.
1869        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1871     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1874     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1875        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1876        for detecting groups that can match an empty string.
1878     9. A pattern with a very large number of alternatives (more than several
1879        hundred) was running out of internal workspace during the pre-compile
1880        phase, where pcre_compile() figures out how much memory will be needed. A
1881        bit of new cunning has reduced the workspace needed for groups with
1882        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1883        workspace instead of running out of the 4096 that are available.
1885    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1887    11. Applied patch from Google to remove an optimization that didn't quite work.
1888        The report of the bug said:
1890          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1891          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1892          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1894    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1895        it matched the wrong number of bytes.
1898    Version 7.1 24-Apr-07
1899    ---------------------
1901     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1902        that is more "standard", making use of automake and other Autotools. There
1903        is some re-arrangement of the files and adjustment of comments consequent
1904        on this.
1906     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1907        for recursive directory scanning broke on some systems because the files
1908        are not scanned in any specific order and on different systems the order
1909        was different. A call to "sort" has been inserted into RunGrepTest for the
1910        approprate test as a short-term fix. In the longer term there may be an
1911        alternative.
1913     3. I had an email from Eric Raymond about problems translating some of PCRE's
1914        man pages to HTML (despite the fact that I distribute HTML pages, some
1915        people do their own conversions for various reasons). The problems
1916        concerned the use of low-level troff macros .br and .in. I have therefore
1917        removed all such uses from the man pages (some were redundant, some could
1918        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1919        HTML has been updated to handle .nf/.fi and to complain if it encounters
1920        .br or .in.
1922     4. Updated comments in configure.ac that get placed in config.h.in and also
1923        arranged for config.h to be included in the distribution, with the name
1924        config.h.generic, for the benefit of those who have to compile without
1925        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1927     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1928        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1929        makevp.bat for the current PCRE, using the additional files
1930        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1932     6. A Windows user reported a minor discrepancy with test 2, which turned out
1933        to be caused by a trailing space on an input line that had got lost in his
1934        copy. The trailing space was an accident, so I've just removed it.
1936     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1937        that is needed.
1939     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1940        as "const" (a) because they are and (b) because it helps the PHP
1941        maintainers who have recently made a script to detect big data structures
1942        in the php code that should be moved to the .rodata section. I remembered
1943        to update Builducptable as well, so it won't revert if ucptable.h is ever
1944        re-created.
1946     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1947        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1948        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1949        support is not required. This saves 1.5-2K of code, which is important in
1950        some applications.
1952        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1953        so as not to refer to the tables, even though these functions will never be
1954        called when UTF-8 support is disabled. Otherwise there are problems with a
1955        shared library.
1957    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1959        (a) It was defining its arguments as char * instead of void *.
1961        (b) It was assuming that all moves were upwards in memory; this was true
1962            a long time ago when I wrote it, but is no longer the case.
1964        The emulated memove() is provided for those environments that have neither
1965        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1966        is clearly not the case, as these two bugs were recently reported.
1968    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1969        and Detrail to create the HTML documentation, the .txt form of the man
1970        pages, and it removes trailing spaces from listed files. It also creates
1971        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1972        case, it wraps all the #defines with #ifndefs. This script should be run
1973        before "make dist".
1975    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1976        with Unicode property support.
1978        (a) For a maximizing quantifier, if the two different cases of the
1979            character were of different lengths in their UTF-8 codings (there are
1980            some cases like this - I found 11), and the matching function had to
1981            back up over a mixture of the two cases, it incorrectly assumed they
1982            were both the same length.
1984        (b) When PCRE was configured to use the heap rather than the stack for
1985            recursion during matching, it was not correctly preserving the data for
1986            the other case of a UTF-8 character when checking ahead for a match
1987            while processing a minimizing repeat. If the check also involved
1988            matching a wide character, but failed, corruption could cause an
1989            erroneous result when trying to check for a repeat of the original
1990            character.
1992    13. Some tidying changes to the testing mechanism:
1994        (a) The RunTest script now detects the internal link size and whether there
1995            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1996            values substituted by "configure". (The RunGrepTest script already did
1997            this for UTF-8.) The configure.ac script no longer substitutes the
1998            relevant variables.
2000        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2001            with length and offset values. This means that the output is different
2002            for different internal link sizes. Test 2 is skipped for link sizes
2003            other than 2 because of this, bypassing the problem. Unfortunately,
2004            there was also a test in test 3 (the locale tests) that used /B and
2005            failed for link sizes other than 2. Rather than cut the whole test out,
2006            I have added a new /Z option to pcretest that replaces the length and
2007            offset values with spaces. This is now used to make test 3 independent
2008            of link size. (Test 2 will be tidied up later.)
2010    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2011        segmentation fault instead of returning the appropriate error message.
2013    15. In multiline mode when the newline sequence was set to "any", the pattern
2014        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2015        This doesn't seem right; it now treats the CRLF combination as the line
2016        ending, and so does not match in that case. It's only a pattern such as ^$
2017        that would hit this one: something like ^ABC$ would have failed after \r
2018        and then tried again after \r\n.
2020    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2021        in an attempt to make files that differ only in their line terminators
2022        compare equal. This works on Linux.
2024    17. Under certain error circumstances pcregrep might try to free random memory
2025        as it exited. This is now fixed, thanks to valgrind.
2027    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2028        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2029        was because its rules for how to advance for /g after matching an empty
2030        string at the end of a line did not allow for this case. They now check for
2031        it specially.
2033    20. pcretest is supposed to handle patterns and data of any length, by
2034        extending its buffers when necessary. It was getting this wrong when the
2035        buffer for a data line had to be extended.
2037    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2038        CRLF as a newline sequence.
2040    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2041        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2042        I have nevertheless tidied it up.
2044    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2046    24. Added a man page for pcre-config.
2049    Version 7.0 19-Dec-06
2050    ---------------------
2052     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2053        moving to gcc 4.1.1.
2055     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2056        sys/time.h, which is documented as needed for this function. It doesn't
2057        seem to matter on Linux, but it showed up on some releases of OS X.
2059     3. It seems that there are systems where bytes whose values are greater than
2060        127 match isprint() in the "C" locale. The "C" locale should be the
2061        default when a C program starts up. In most systems, only ASCII printing
2062        characters match isprint(). This difference caused the output from pcretest
2063        to vary, making some of the tests fail. I have changed pcretest so that:
2065        (a) When it is outputting text in the compiled version of a pattern, bytes
2066            other than 32-126 are always shown as hex escapes.
2068        (b) When it is outputting text that is a matched part of a subject string,
2069            it does the same, unless a different locale has been set for the match
2070            (using the /L modifier). In this case, it uses isprint() to decide.
2072     4. Fixed a major bug that caused incorrect computation of the amount of memory
2073        required for a compiled pattern when options that changed within the
2074        pattern affected the logic of the preliminary scan that determines the
2075        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2076        that the computed length was too small. The symptoms of this bug were
2077        either the PCRE error "internal error: code overflow" from pcre_compile(),
2078        or a glibc crash with a message such as "pcretest: free(): invalid next
2079        size (fast)". Examples of patterns that provoked this bug (shown in
2080        pcretest format) are:
2082          /(?-x: )/x
2083          /(?x)(?-x: \s*#\s*)/
2084          /((?i)[\x{c0}])/8
2085          /(?i:[\x{c0}])/8
2087        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2088        is now done differently.
2090     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2091        wrapper classes; (b) implement a new function in the C++ scanner that is
2092        more efficient than the old way of doing things because it avoids levels of
2093        recursion in the regex matching; (c) add a paragraph to the documentation
2094        for the FullMatch() function.
2096     6. The escape sequence \n was being treated as whatever was defined as
2097        "newline". Not only was this contrary to the documentation, which states
2098        that \n is character 10 (hex 0A), but it also went horribly wrong when
2099        "newline" was defined as CRLF. This has been fixed.
2101     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2102        was being set to -1 for the "end of line" case (supposedly a value that no
2103        character can have). Though this value is never used (the check for end of
2104        line is "zero bytes in current character"), it caused compiler complaints.
2105        I've changed it to 0xffffffff.
2107     8. In pcre_version.c, the version string was being built by a sequence of
2108        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2109        string (as it is for production releases) called a macro with an empty
2110        argument. The C standard says the result of this is undefined. The gcc
2111        compiler treats it as an empty string (which was what was wanted) but it is
2112        reported that Visual C gives an error. The source has been hacked around to
2113        avoid this problem.
2115     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2116        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2117        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2118        of them did).
2120    10. Originally, pcretest opened its input and output without "b"; then I was
2121        told that "b" was needed in some environments, so it was added for release
2122        5.0 to both the input and output. (It makes no difference on Unix-like
2123        systems.) Later I was told that it is wrong for the input on Windows. I've
2124        now abstracted the modes into two macros, to make it easier to fiddle with
2125        them, and removed "b" from the input mode under Windows.
2127    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2129    12. Added -help and --help to pcretest as an official way of being reminded
2130        of the options.
2132    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2133        and pcrecpp.cc because they annoy compilers at high warning levels.
2135    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2137    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2138        scripts are not C programs :-) and which was not noticed because it works
2139        on Linux.
2141    16. pcretest is supposed to handle any length of pattern and data line (as one
2142        line or as a continued sequence of lines) by extending its input buffer if
2143        necessary. This feature was broken for very long pattern lines, leading to
2144        a string of junk being passed to pcre_compile() if the pattern was longer
2145        than about 50K.
2147    17. I have done a major re-factoring of the way pcre_compile() computes the
2148        amount of memory needed for a compiled pattern. Previously, there was code
2149        that made a preliminary scan of the pattern in order to do this. That was
2150        OK when PCRE was new, but as the facilities have expanded, it has become
2151        harder and harder to keep it in step with the real compile phase, and there
2152        have been a number of bugs (see for example, 4 above). I have now found a
2153        cunning way of running the real compile function in a "fake" mode that
2154        enables it to compute how much memory it would need, while actually only
2155        ever using a few hundred bytes of working memory and without too many
2156        tests of the mode. This should make future maintenance and development
2157        easier. A side effect of this work is that the limit of 200 on the nesting
2158        depth of parentheses has been removed (though this was never a serious
2159        limitation, I suspect). However, there is a downside: pcre_compile() now
2160        runs more slowly than before (30% or more, depending on the pattern). I
2161        hope this isn't a big issue. There is no effect on runtime performance.
2163    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2164        newline (only possible for the last line of a file) and it was a
2165        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2167    19. Added additional timing features to pcretest. (1) The -tm option now times
2168        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2169        separate command line item, by a number that specifies the number of
2170        repeats to use when timing. The default is 50000; this gives better
2171        precision, but takes uncomfortably long for very large patterns.
2173    20. Extended pcre_study() to be more clever in cases where a branch of a
2174        subpattern has no definite first character. For example, (a*|b*)[cd] would
2175        previously give no result from pcre_study(). Now it recognizes that the
2176        first character must be a, b, c, or d.
2178    21. There was an incorrect error "recursive call could loop indefinitely" if
2179        a subpattern (or the entire pattern) that was being tested for matching an
2180        empty string contained only one non-empty item after a nested subpattern.
2181        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2182        incorrectly, because the \d was being skipped in the check.
2184    22. The pcretest program now has a new pattern option /B and a command line
2185        option -b, which is equivalent to adding /B to every pattern. This causes
2186        it to show the compiled bytecode, without the additional information that
2187        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2188        is the same as /B/I).
2190    23. A new optimization is now able automatically to treat some sequences such
2191        as a*b as a*+b. More specifically, if something simple (such as a character
2192        or a simple class like \d) has an unlimited quantifier, and is followed by
2193        something that cannot possibly match the quantified thing, the quantifier
2194        is automatically "possessified".
2196    24. A recursive reference to a subpattern whose number was greater than 39
2197        went wrong under certain circumstances in UTF-8 mode. This bug could also
2198        have affected the operation of pcre_study().
2200    25. Realized that a little bit of performance could be had by replacing
2201        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2203    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2205    27. Possessive quantifiers such as a++ were previously implemented by turning
2206        them into atomic groups such as ($>a+). Now they have their own opcodes,
2207        which improves performance. This includes the automatically created ones
2208        from 23 above.
2210    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2211        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2212        the first matched character to be a colon. This applied both to named and
2213        numbered groups.
2215    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2217    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2218        building PCRE on Windows easier, so I have included it in the distribution.
2220    31. There is now a check in pcretest against a ridiculously large number being
2221        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2222        loop, the loop is abandoned.
2224    32. Forward references to subpatterns in conditions such as (?(2)...) where
2225        subpattern 2 is defined later cause pcre_compile() to search forwards in
2226        the pattern for the relevant set of parentheses. This search went wrong
2227        when there were unescaped parentheses in a character class, parentheses
2228        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2230    33. "Subroutine" calls and backreferences were previously restricted to
2231        referencing subpatterns earlier in the regex. This restriction has now
2232        been removed.
2234    34. Added a number of extra features that are going to be in Perl 5.10. On the
2235        whole, these are just syntactic alternatives for features that PCRE had
2236        previously implemented using the Python syntax or my own invention. The
2237        other formats are all retained for compatibility.
2239        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2240            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2241            also .NET compatible.
2243        (b) A recursion or subroutine call to a named group can now be defined as
2244            (?&name) as well as (?P>name).
2246        (c) A backreference to a named group can now be defined as \k<name> or
2247            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2248            5.10, are also .NET compatible.
2250        (d) A conditional reference to a named group can now use the syntax
2251            (?(<name>) or (?('name') as well as (?(name).
2253        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2254            groups (named and numbered) that are never evaluated inline, but can be
2255            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2256            is always false. There may be only one alternative in such a group.
2258        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2259            as the simple (?(R). The condition is true only if the most recent
2260            recursion is that of the given number or name. It does not search out
2261            through the entire recursion stack.
2263        (g) The escape \gN or \g{N} has been added, where N is a positive or
2264            negative number, specifying an absolute or relative reference.
2266    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2267        some "unreachable code" warnings.
2269    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2270        things, this adds five new scripts.
2272    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2273        There were also incompatibilities regarding the handling of \Q..\E inside
2274        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2275        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2277    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2278        matches an empty string, and forcibly breaks the loop. There were bugs in
2279        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2280        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2281        separate and independent bugs (that affected different cases) have been
2282        fixed.
2284    39. Refactored the code to abolish the use of different opcodes for small
2285        capturing bracket numbers. This is a tidy that I avoided doing when I
2286        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2287        The new approach is not only tidier, it makes it possible to reduce the
2288        memory needed to fix the previous bug (38).
2290    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2291        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2292        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2293        mode.
2295    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2296        report.
2298    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2299        copy construction and assignment in the C++ wrapper.
2301    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2302        couple of bugs that could have given wrong results in the "--newline=crlf"
2303        case.
2305    44. Added a number of casts and did some reorganization of signed/unsigned int
2306        variables following suggestions from Dair Grant. Also renamed the variable
2307        "this" as "item" because it is a C++ keyword.
2309    45. Arranged for dftables to add
2311          #include "pcre_internal.h"
2313        to pcre_chartables.c because without it, gcc 4.x may remove the array
2314        definition from the final binary if PCRE is built into a static library and
2315        dead code stripping is activated.
2317    46. For an unanchored pattern, if a match attempt fails at the start of a
2318        newline sequence, and the newline setting is CRLF or ANY, and the next two
2319        characters are CRLF, advance by two characters instead of one.
2322    Version 6.7 04-Jul-06
2323    ---------------------
2325     1. In order to handle tests when input lines are enormously long, pcretest has
2326        been re-factored so that it automatically extends its buffers when
2327        necessary. The code is crude, but this _is_ just a test program. The
2328        default size has been increased from 32K to 50K.
2330     2. The code in pcre_study() was using the value of the re argument before
2331        testing it for NULL. (Of course, in any sensible call of the function, it
2332        won't be NULL.)
2334     3. The memmove() emulation function in pcre_internal.h, which is used on
2335        systems that lack both memmove() and bcopy() - that is, hardly ever -
2336        was missing a "static" storage class specifier.
2338     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2339        containing an extended class (one that cannot be represented by a bitmap
2340        because it contains high-valued characters or Unicode property items, e.g.
2341        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2342        pattern, but PCRE should not loop if you do not (it no longer does).
2343        [Detail: two cases were found: (a) a repeated subpattern containing an
2344        extended class; (b) a recursive reference to a subpattern that followed a
2345        previous extended class. It wasn't skipping over the extended class
2346        correctly when UTF-8 mode was not set.]
2348     5. A negated single-character class was not being recognized as fixed-length
2349        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2350        compile error "lookbehind assertion is not fixed length".
2352     6. The RunPerlTest auxiliary script was showing an unexpected difference
2353        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2354        write a Perl script that can interpret lines of an input file either as
2355        byte characters or as UTF-8, which is what "perltest" was being required to
2356        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2357        can't do is switch easily at run time between having the "use utf8;" pragma
2358        or not. In the end, I fudged it by using the RunPerlTest script to insert
2359        "use utf8;" explicitly for the UTF-8 tests.
2361     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2362        the end of the subject string, contrary to the documentation and to what
2363        Perl does. This was true of both matching functions. Now it matches only at
2364        the start of the subject and immediately after *internal* newlines.
2366     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2367        a pointer to an int instead of a pointer to an unsigned long int. This
2368        caused problems on 64-bit systems.
2370     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2371        instance of the 'standard' template library not being so standard".
2373    10. There was no check on the number of named subpatterns nor the maximum
2374        length of a subpattern name. The product of these values is used to compute
2375        the size of the memory block for a compiled pattern. By supplying a very
2376        long subpattern name and a large number of named subpatterns, the size
2377        computation could be caused to overflow. This is now prevented by limiting
2378        the length of names to 32 characters, and the number of named subpatterns
2379        to 10,000.
2381    11. Subpatterns that are repeated with specific counts have to be replicated in
2382        the compiled pattern. The size of memory for this was computed from the
2383        length of the subpattern and the repeat count. The latter is limited to
2384        65535, but there was no limit on the former, meaning that integer overflow
2385        could in principle occur. The compiled length of a repeated subpattern is
2386        now limited to 30,000 bytes in order to prevent this.
2388    12. Added the optional facility to have named substrings with the same name.
2390    13. Added the ability to use a named substring as a condition, using the
2391        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2392        are numbers (not recommended). Forward references are permitted.
2394    14. Added forward references in named backreferences (if you see what I mean).
2396    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2397        pattern could run off the end of the subject. For example, the pattern
2398        "(?s)(.{1,5})"8 did this with the subject "ab".
2400    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2401        PCRE_CASELESS was set when matching characters that were quantified with ?
2402        or *.
2404    17. A character class other than a single negated character that had a minimum
2405        but no maximum quantifier - for example [ab]{6,} - was not handled
2406        correctly by pce_dfa_exec(). It would match only one character.
2408    18. A valid (though odd) pattern that looked like a POSIX character
2409        class but used an invalid character after [ (for example [[,abc,]]) caused
2410        pcre_compile() to give the error "Failed: internal error: code overflow" or
2411        in some cases to crash with a glibc free() error. This could even happen if
2412        the pattern terminated after [[ but there just happened to be a sequence of
2413        letters, a binary zero, and a closing ] in the memory that followed.
2415    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2416        over the years. Originally (before any Unicode support), just the bottom 8
2417        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2418        output from "man perlunicode" includes this:
2420          The regular expression compiler produces polymorphic opcodes.  That
2421          is, the pattern adapts to the data and automatically switches to
2422          the Unicode character scheme when presented with Unicode data--or
2423          instead uses a traditional byte scheme when presented with byte
2424          data.
2426        Sadly, a wide octal escape does not cause a switch, and in a string with
2427        no other multibyte characters, these octal escapes are treated as before.
2428        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2429        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2430        Unicode string.
2432        I have not perpetrated such confusion in PCRE. Up till now, it took just
2433        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2434        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2435        translate to the appropriate multibyte character.
2437    29. Applied some refactoring to reduce the number of warnings from Microsoft
2438        and Borland compilers. This has included removing the fudge introduced
2439        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2440        a warning about an unused variable.
2442    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2443        characters since release 4.0, because Perl (from release 5.004) does not.
2444        [Or at least, is documented not to: some releases seem to be in conflict
2445        with the documentation.] However, when a pattern was studied with
2446        pcre_study() and all its branches started with \s, PCRE still included VT
2447        as a possible starting character. Of course, this did no harm; it just
2448        caused an unnecessary match attempt.
2450    22. Removed a now-redundant internal flag bit that recorded the fact that case
2451        dependency changed within the pattern. This was once needed for "required
2452        byte" processing, but is no longer used. This recovers a now-scarce options
2453        bit. Also moved the least significant internal flag bit to the most-
2454        significant bit of the word, which was not previously used (hangover from
2455        the days when it was an int rather than a uint) to free up another bit for
2456        the future.
2458    23. Added support for CRLF line endings as well as CR and LF. As well as the
2459        default being selectable at build time, it can now be changed at runtime
2460        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2461        specify that it is scanning data with non-default line endings.
2463    24. Changed the definition of CXXLINK to make it agree with the definition of
2464        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2466    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2467        recursions. This makes a big different to stack usage for some patterns.
2469    26. If a subpattern containing a named recursion or subroutine reference such
2470        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2471        the space required for the compiled pattern went wrong and gave too small a
2472        value. Depending on the environment, this could lead to "Failed: internal
2473        error: code overflow at offset 49" or "glibc detected double free or
2474        corruption" errors.
2476    27. Applied patches from Google (a) to support the new newline modes and (b) to
2477        advance over multibyte UTF-8 characters in GlobalReplace.
2479    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2480        difference for some implementation of PCRE in some Windows version.
2482    29. Added some extra testing facilities to pcretest:
2484        \q<number>   in a data line sets the "match limit" value
2485        \Q<number>   in a data line sets the "match recursion limt" value
2486        -S <number>  sets the stack size, where <number> is in megabytes
2488        The -S option isn't available for Windows.
2491    Version 6.6 06-Feb-06
2492    ---------------------
2494     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2495        in pcreposix.h. I have copied the definition from pcre.h.
2497     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2498        because pcre.h is no longer a built file.
2500     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2501        not normally included in the compiled code.
2504    Version 6.5 01-Feb-06
2505    ---------------------
2507     1. When using the partial match feature with pcre_dfa_exec(), it was not
2508        anchoring the second and subsequent partial matches at the new starting
2509        point. This could lead to incorrect results. For example, with the pattern
2510        /1234/, partially matching against "123" and then "a4" gave a match.
2512     2. Changes to pcregrep:
2514        (a) All non-match returns from pcre_exec() were being treated as failures
2515            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2516            error message is output. Some extra information is given for the
2517            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2518            probably the only errors that are likely to be caused by users (by
2519            specifying a regex that has nested indefinite repeats, for instance).
2520            If there are more than 20 of these errors, pcregrep is abandoned.
2522        (b) A binary zero was treated as data while matching, but terminated the
2523            output line if it was written out. This has been fixed: binary zeroes
2524            are now no different to any other data bytes.
2526        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2527            used to set a locale for matching. The --locale=xxxx long option has
2528            been added (no short equivalent) to specify a locale explicitly on the
2529            pcregrep command, overriding the environment variables.
2531        (d) When -B was used with -n, some line numbers in the output were one less
2532            than they should have been.
2534        (e) Added the -o (--only-matching) option.
2536        (f) If -A or -C was used with -c (count only), some lines of context were
2537            accidentally printed for the final match.
2539        (g) Added the -H (--with-filename) option.
2541        (h) The combination of options -rh failed to suppress file names for files
2542            that were found from directory arguments.
2544        (i) Added the -D (--devices) and -d (--directories) options.
2546        (j) Added the -F (--fixed-strings) option.
2548        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2550        (l) Added the --colo(u)r option.
2552        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2553            is not present by default.
2555     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2556        items such as (?R) or (?1), when the recursion could match a number of
2557        alternatives. If it matched one of the alternatives, but subsequently,
2558        outside the recursion, there was a failure, the code tried to back up into
2559        the recursion. However, because of the way PCRE is implemented, this is not
2560        possible, and the result was an incorrect result from the match.
2562        In order to prevent this happening, the specification of recursion has
2563        been changed so that all such subpatterns are automatically treated as
2564        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2566     4. I had overlooked the fact that, in some locales, there are characters for
2567        which isalpha() is true but neither isupper() nor islower() are true. In
2568        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2569        and ordfeminine) are like this. This affected the treatment of \w and \W
2570        when they appeared in character classes, but not when they appeared outside
2571        a character class. The bit map for "word" characters is now created
2572        separately from the results of isalnum() instead of just taking it from the
2573        upper, lower, and digit maps. (Plus the underscore character, of course.)
2575     5. The above bug also affected the handling of POSIX character classes such as
2576        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2577        permanent tables. Instead, the bit maps for such a class were previously
2578        created as the appropriate unions of the upper, lower, and digit bitmaps.
2579        Now they are created by subtraction from the [[:word:]] class, which has
2580        its own bitmap.
2582     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2583        It is created by subtracting the vertical space characters (\x09, \x0a,
2584        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2585        subtraction was done in the overall bitmap for a character class, meaning
2586        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2587        be recognized. This bug has been fixed.
2589     7. Patches from the folks at Google:
2591          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2592          real life, but is still worth protecting against".
2594          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2595          regular expressions".
2597          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2598          have it.
2600          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2601          "configure" and the latter not, in order to fix a problem somebody had
2602          with compiling the Arg class on HP-UX.
2604          (e) Improve the error-handling of the C++ wrapper a little bit.
2606          (f) New tests for checking recursion limiting.
2608     8. The pcre_memmove() function, which is used only if the environment does not
2609        have a standard memmove() function (and is therefore rarely compiled),
2610        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2611        returning a result (though PCRE never actually uses the result).
2613     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2614        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2615        returned instead of calling malloc() with an overflowing number that would
2616        most likely cause subsequent chaos.
2618    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2620    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2621        with this option is matched, the nmatch and pmatch options of regexec() are
2622        ignored.
2624    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2625        provided in case anyone wants to the the POSIX interface with UTF-8
2626        strings.
2628    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2629        C++ linking (needed for some HP-UX environments).
2631    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2632        (unused parameter) and in the pcre_printint() function (omitted "default"
2633        switch label when the default is to do nothing).
2635    15. Added some code to make it possible, when PCRE is compiled as a C++
2636        library, to replace subject pointers for pcre_exec() with a smart pointer
2637        class, thus making it possible to process discontinuous strings.
2639    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2640        much the same function. They were added by different people who were trying
2641        to make PCRE easy to compile on non-Unix systems. It has been suggested
2642        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2643        for compiling on Windows systems. I have therefore replaced it with
2644        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2645        defaults to "extern" for C or "extern C" for C++, which works fine on
2646        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2647        SCOPE with something explicit in config.h. In addition:
2649        (a) pcreposix.h still had just "extern" instead of either of these macros;
2650            I have replaced it with PCRE_DATA_SCOPE.
2652        (b) Functions such as _pcre_xclass(), which are internal to the library,
2653            but external in the C sense, all had PCRE_EXPORT in their definitions.
2654            This is apparently wrong for the Windows case, so I have removed it.
2655            (It makes no difference on Unix-like systems.)
2657    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2658        of recursive calls to match(). This is different to MATCH_LIMIT because
2659        that limits the total number of calls to match(), not all of which increase
2660        the depth of recursion. Limiting the recursion depth limits the amount of
2661        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2662        when PCRE is compiled, and changed at run time. A patch from Google adds
2663        this functionality to the C++ interface.
2665    18. Changes to the handling of Unicode character properties:
2667        (a) Updated the table to Unicode 4.1.0.
2669        (b) Recognize characters that are not in the table as "Cn" (undefined).
2671        (c) I revised the way the table is implemented to a much improved format
2672            which includes recognition of ranges. It now supports the ranges that
2673            are defined in UnicodeData.txt, and it also amalgamates other
2674            characters into ranges. This has reduced the number of entries in the
2675            table from around 16,000 to around 3,000, thus reducing its size
2676            considerably. I realized I did not need to use a tree structure after
2677            all - a binary chop search is just as efficient. Having reduced the
2678            number of entries, I extended their size from 6 bytes to 8 bytes to
2679            allow for more data.
2681        (d) Added support for Unicode script names via properties such as \p{Han}.
2683    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2684        matching that character.
2686    20. When matching a repeated Unicode property with a minimum greater than zero,
2687        (for example \pL{2,}), PCRE could look past the end of the subject if it
2688        reached it while seeking the minimum number of characters. This could
2689        happen only if some of the characters were more than one byte long, because
2690        there is a check for at least the minimum number of bytes.
2692    21. Refactored the implementation of \p and \P so as to be more general, to
2693        allow for more different types of property in future. This has changed the
2694        compiled form incompatibly. Anybody with saved compiled patterns that use
2695        \p or \P will have to recompile them.
2697    22. Added "Any" and "L&" to the supported property types.
2699    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2700        but give a compile time error if the value is greater than 0xff.
2702    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2703        accidentally not being installed or uninstalled.
2705    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2706        made were to insert the current release number. This seemed silly, because
2707        it made things harder for people building PCRE on systems that don't run
2708        "configure". I have turned pcre.h into a distributed file, no longer built
2709        by "configure", with the version identification directly included. There is
2710        no longer a pcre.h.in file.
2712        However, this change necessitated a change to the pcre-config script as
2713        well. It is built from pcre-config.in, and one of the substitutions was the
2714        release number. I have updated configure.ac so that ./configure now finds
2715        the release number by grepping pcre.h.
2717    26. Added the ability to run the tests under valgrind.
2720    Version 6.4 05-Sep-05
2721    ---------------------
2723     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2724        "--" to be printed when multiple files were scanned, even when none of the
2725        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2726        consider it to be a bug, and have restored the previous behaviour.
2728     2. A couple of code tidies to get rid of compiler warnings.
2730     3. The pcretest program used to cheat by referring to symbols in the library
2731        whose names begin with _pcre_. These are internal symbols that are not
2732        really supposed to be visible externally, and in some environments it is
2733        possible to suppress them. The cheating is now confined to including
2734        certain files from the library's source, which is a bit cleaner.
2736     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2737        file's purpose clearer.
2739     5. Reorganized pcre_ucp_findchar().
2742    Version 6.3 15-Aug-05
2743    ---------------------
2745     1. The file libpcre.pc.in did not have general read permission in the tarball.
2747     2. There were some problems when building without C++ support:
2749        (a) If C++ support was not built, "make install" and "make test" still
2750            tried to test it.
2752        (b) There were problems when the value of CXX was explicitly set. Some
2753            changes have been made to try to fix these, and ...
2755        (c) --disable-cpp can now be used to explicitly disable C++ support.
2757        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2758            backslash in a target when C++ was disabled. This confuses some
2759            versions of "make", apparently. Using an intermediate variable solves
2760            this. (Same for CPP_LOBJ.)
2762     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2763        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2764        necessary on certain architectures.
2766     4. Added a setting of -export-symbols-regex to the link command to remove
2767        those symbols that are exported in the C sense, but actually are local
2768        within the library, and not documented. Their names all begin with
2769        "_pcre_". This is not a perfect job, because (a) we have to except some
2770        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2771        available (and never for static libraries). I have made a note to try to
2772        find a way round (a) in the future.
2775  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
2776  ---------------------  ---------------------

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