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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.13 30-Apr-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
177    Version 8.12 15-Jan-2011
178    ------------------------
180    1.  Fixed some typos in the markup of the man pages, and wrote a script that
181        checks for such things as part of the documentation building process.
183    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
184        --match-limit and --recursion-limit options (added for 8.11). In
185        particular, this made one of the standard tests fail. (The integer value
186        went into the wrong half of a long int.)
188    3.  If the --colour option was given to pcregrep with -v (invert match), it
189        did strange things, either producing crazy output, or crashing. It should,
190        of course, ignore a request for colour when reporting lines that do not
191        match.
193    4.  Another pcregrep bug caused similar problems if --colour was specified with
194        -M (multiline) and the pattern match finished with a line ending.
196    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
197        matched in multiline mode, the following line was shown as part of the
198        match. This seems wrong, so I have changed it.
200    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
201        the check for further matches in the same line (so they could be coloured)
202        to overrun the end of the current line. If another match was found, it was
203        incorrectly shown (and then shown again when found in the next line).
205    7.  If pcregrep was compiled under Windows, there was a reference to the
206        function pcregrep_exit() before it was defined. I am assuming this was
207        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
208        reported by a user. I've moved the definition above the reference.
211    Version 8.11 10-Dec-2010
212    ------------------------
214    1.  (*THEN) was not working properly if there were untried alternatives prior
215        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
216        backtracked to try for "b" instead of moving to the next alternative branch
217        at the same level (in this case, to look for "c"). The Perl documentation
218        is clear that when (*THEN) is backtracked onto, it goes to the "next
219        alternative in the innermost enclosing group".
221    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
222        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
223        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
224        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
225        (*THEN).
227    3.  If \s appeared in a character class, it removed the VT character from
228        the class, even if it had been included by some previous item, for example
229        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
230        of \s, but is part of the POSIX "space" class.)
232    4.  A partial match never returns an empty string (because you can always
233        match an empty string at the end of the subject); however the checking for
234        an empty string was starting at the "start of match" point. This has been
235        changed to the "earliest inspected character" point, because the returned
236        data for a partial match starts at this character. This means that, for
237        example, /(?<=abc)def/ gives a partial match for the subject "abc"
238        (previously it gave "no match").
240    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
241        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
242        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
243        has an implication that the given string is incomplete (because a partial
244        match is preferred over a full match). For this reason, these items now
245        give a partial match in this situation. [Aside: previously, the one case
246        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
247        match rather than a full match, which was wrong by the old rules, but is
248        now correct.]
250    6.  There was a bug in the handling of #-introduced comments, recognized when
251        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
252        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
253        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
254        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
255        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
256        places in pcre_compile().
258    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
259        comments when looking ahead for named forward references to subpatterns,
260        the only newline sequence it recognized was NL. It now handles newlines
261        according to the set newline convention.
263    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
264        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
265        cater for a lack of strerror(). These oversights have been fixed.
267    9.  Added --match-limit and --recursion-limit to pcregrep.
269    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
271    11. When the -o option was used, pcregrep was setting a return code of 1, even
272        when matches were found, and --line-buffered was not being honoured.
274    12. Added an optional parentheses number to the -o and --only-matching options
275        of pcregrep.
277    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
278        can match an empty string. The code to do it in pcretest and pcredemo
279        needed fixing:
281        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
282            only one byte after an empty string match just before CRLF (this case
283            just got forgotten; "any" and "anycrlf" were OK).
285        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
286            mode when an empty string match preceded an ASCII character followed by
287            a non-ASCII character. (The code for advancing by one character rather
288            than one byte was nonsense.)
290        (c) The pcredemo.c sample program did not have any code at all to handle
291            the cases when CRLF is a valid newline sequence.
293    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
294        as a starting offset was within the subject string. There is now a new
295        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
296        negative or greater than the length of the string. In order to test this,
297        pcretest is extended to allow the setting of negative starting offsets.
299    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
300        starting offset points to the beginning of a UTF-8 character was
301        unnecessarily clumsy. I tidied it up.
303    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
304        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
306    17. Nobody had reported that the --include_dir option, which was added in
307        release 7.7 should have been called --include-dir (hyphen, not underscore)
308        for compatibility with GNU grep. I have changed it to --include-dir, but
309        left --include_dir as an undocumented synonym, and the same for
310        --exclude-dir, though that is not available in GNU grep, at least as of
311        release 2.5.4.
313    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
314        characters from a string of bytes) have been redefined so as not to use
315        loops, in order to improve performance in some environments. At the same
316        time, I abstracted some of the common code into auxiliary macros to save
317        repetition (this should not affect the compiled code).
319    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
320        compile-time error is now given if \c is not followed by an ASCII
321        character, that is, a byte less than 128. (In EBCDIC mode, the code is
322        different, and any byte value is allowed.)
324    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
325        START_OPTIMIZE option, which is now allowed at compile time - but just
326        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
327        to pcregrep and other applications that have no direct access to PCRE
328        options. The new /Y option in pcretest sets this option when calling
329        pcre_compile().
331    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
332        back references. Groups containing recursive back references were forced to
333        be atomic by that change, but in the case of named groups, the amount of
334        memory required was incorrectly computed, leading to "Failed: internal
335        error: code overflow". This has been fixed.
337    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
338        pcretest.c, to avoid build problems in some Borland environments.
341    Version 8.10 25-Jun-2010
342    ------------------------
344    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
345        THEN.
347    2.  (*ACCEPT) was not working when inside an atomic group.
349    3.  Inside a character class, \B is treated as a literal by default, but
350        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
351        causes the error). The code is unchanged, but I tidied the documentation.
353    4.  Inside a character class, PCRE always treated \R and \X as literals,
354        whereas Perl faults them if its -w option is set. I have changed PCRE so
355        that it faults them when PCRE_EXTRA is set.
357    5.  Added support for \N, which always matches any character other than
358        newline. (It is the same as "." when PCRE_DOTALL is not set.)
360    6.  When compiling pcregrep with newer versions of gcc which may have
361        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
362        declared with attribute warn_unused_result" were given. Just casting the
363        result to (void) does not stop the warnings; a more elaborate fudge is
364        needed. I've used a macro to implement this.
366    7.  Minor change to pcretest.c to avoid a compiler warning.
368    8.  Added four artifical Unicode properties to help with an option to make
369        \s etc use properties (see next item). The new properties are: Xan
370        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
372    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
373        use Unicode properties. (*UCP) at the start of a pattern can be used to set
374        this option. Modified pcretest to add /W to test this facility. Added
375        REG_UCP to make it available via the POSIX interface.
377    10. Added --line-buffered to pcregrep.
379    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
380        studied, and the match started with a letter with a code point greater than
381        127 whose first byte was different to the first byte of the other case of
382        the letter, the other case of this starting letter was not recognized
383        (#976).
385    12. If a pattern that was studied started with a repeated Unicode property
386        test, for example, \p{Nd}+, there was the theoretical possibility of
387        setting up an incorrect bitmap of starting bytes, but fortunately it could
388        not have actually happened in practice until change 8 above was made (it
389        added property types that matched character-matching opcodes).
391    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
392        possible starting bytes for non-anchored patterns.
394    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
395        \R, and also a number of cases that involve Unicode properties, both
396        explicit and implicit when PCRE_UCP is set.
398    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
399        input, it could crash or give wrong results if characters with values
400        greater than 0xc0 were present in the subject string. (Detail: it assumed
401        UTF-8 input when processing these items.)
403    16. Added a lot of (int) casts to avoid compiler warnings in systems where
404        size_t is 64-bit (#991).
406    17. Added a check for running out of memory when PCRE is compiled with
407        --disable-stack-for-recursion (#990).
409    18. If the last data line in a file for pcretest does not have a newline on
410        the end, a newline was missing in the output.
412    19. The default pcre_chartables.c file recognizes only ASCII characters (values
413        less than 128) in its various bitmaps. However, there is a facility for
414        generating tables according to the current locale when PCRE is compiled. It
415        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
416        characters, are recognized by isspace() and therefore were getting set in
417        these tables, and indeed these tables seem to approximate to ISO 8859. This
418        caused a problem in UTF-8 mode when pcre_study() was used to create a list
419        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
420        which of course cannot start UTF-8 characters. I have changed the code so
421        that only real ASCII characters (less than 128) and the correct starting
422        bytes for UTF-8 encodings are set for characters greater than 127 when in
423        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
424        altogether.)
426    20. Added the /T option to pcretest so as to be able to run tests with non-
427        standard character tables, thus making it possible to include the tests
428        used for 19 above in the standard set of tests.
430    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
431        reference to a subpattern the other side of a comment that contains an
432        opening parenthesis caused either an internal compiling error, or a
433        reference to the wrong subpattern.
436    Version 8.02 19-Mar-2010
437    ------------------------
439    1.  The Unicode data tables have been updated to Unicode 5.2.0.
441    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
442        configured.
444    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
445        original author of that file, following a query about its status.
447    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
448        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
450    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
451        quantifier applied to a forward-referencing subroutine call, could compile
452        incorrect code or give the error "internal error: previously-checked
453        referenced subpattern not found".
455    6.  Both MS Visual Studio and Symbian OS have problems with initializing
456        variables to point to external functions. For these systems, therefore,
457        pcre_malloc etc. are now initialized to local functions that call the
458        relevant global functions.
460    7.  There were two entries missing in the vectors called coptable and poptable
461        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
462        I've fixed the data, and added a kludgy way of testing at compile time that
463        the lengths are correct (equal to the number of opcodes).
465    8.  Following on from 7, I added a similar kludge to check the length of the
466        eint vector in pcreposix.c.
468    9.  Error texts for pcre_compile() are held as one long string to avoid too
469        much relocation at load time. To find a text, the string is searched,
470        counting zeros. There was no check for running off the end of the string,
471        which could happen if a new error number was added without updating the
472        string.
474    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
476    11. \K was not working if it appeared in an atomic group or in a group that
477        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
478        \K is "not well defined" if used in an assertion. PCRE now accepts it if
479        the assertion is positive, but not if it is negative.
481    12. Change 11 fortuitously reduced the size of the stack frame used in the
482        "match()" function of pcre_exec.c by one pointer. Forthcoming
483        implementation of support for (*MARK) will need an extra pointer on the
484        stack; I have reserved it now, so that the stack frame size does not
485        decrease.
487    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
488        item in branch that calls a recursion is a subroutine call - as in the
489        second branch in the above example - was incorrectly given the compile-
490        time error "recursive call could loop indefinitely" because pcre_compile()
491        was not correctly checking the subroutine for matching a non-empty string.
493    14. The checks for overrunning compiling workspace could trigger after an
494        overrun had occurred. This is a "should never occur" error, but it can be
495        triggered by pathological patterns such as hundreds of nested parentheses.
496        The checks now trigger 100 bytes before the end of the workspace.
498    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
501    Version 8.01 19-Jan-2010
502    ------------------------
504    1.  If a pattern contained a conditional subpattern with only one branch (in
505        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
506        computed the wrong minimum data length (which is of course zero for such
507        subpatterns). This could cause incorrect "no match" results.
509    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
510        the pattern is reset in the first branch, pcre_compile() failed with
511        "internal error: code overflow at offset...". This happened only when
512        the reset was to the original external option setting. (An optimization
513        abstracts leading options settings into an external setting, which was the
514        cause of this.)
516    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
517        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
518        assertion pattern did not match (meaning that the assertion was true), it
519        was incorrectly treated as false if the SKIP had been reached during the
520        matching. This also applied to assertions used as conditions.
522    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
523        assertion subpattern, including such a pattern used as a condition,
524        unpredictable results occurred, instead of the error return
527    5.  The C++ GlobalReplace function was not working like Perl for the special
528        situation when an empty string is matched. It now does the fancy magic
529        stuff that is necessary.
531    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
532        removed. (These were left over from very, very early versions of PCRE.)
534    7.  Some cosmetic changes to the code to make life easier when compiling it
535        as part of something else:
537        (a) Change DEBUG to PCRE_DEBUG.
539        (b) In pcre_compile(), rename the member of the "branch_chain" structure
540            called "current" as "current_branch", to prevent a collision with the
541            Linux macro when compiled as a kernel module.
543        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
544            prevent a collision with the Linux macro when compiled as a kernel
545            module.
547    8.  In pcre_compile() there are some checks for integer overflows that used to
548        cast potentially large values to (double). This has been changed to that
549        when building, a check for int64_t is made, and if it is found, it is used
550        instead, thus avoiding the use of floating point arithmetic. (There is no
551        other use of FP in PCRE.) If int64_t is not found, the fallback is to
552        double.
554    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
555        2005 (difference between two addresses compared to an unsigned value).
557    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
558        custom one, because of the following reported problem in Windows:
560          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
561              under Win32.
562          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
563              therefore missing the function definition.
564          - The compiler thus generates a "C" signature for the test function.
565          - The linker fails to find the "C" function.
566          - PCRE fails to configure if asked to do so against libbz2.
568    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
569        messages were output:
571          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
572          rerunning libtoolize, to keep the correct libtool macros in-tree.
573          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
575        I have done both of these things.
577    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
578        most of the time, it *can* run out if it is given a pattern that contains a
579        runaway infinite recursion. I updated the discussion in the pcrestack man
580        page.
582    13. Now that we have gone to the x.xx style of version numbers, the minor
583        version may start with zero. Using 08 or 09 is a bad idea because users
584        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
585        interpreted as invalid octal numbers. I've updated the previous comment in
586        configure.ac, and also added a check that gives an error if 08 or 09 are
587        used.
589    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
590        causing partial matching to fail when the end of the subject matched \W
591        in a UTF-8 pattern where \W was quantified with a minimum of 3.
593    15. There were some discrepancies between the declarations in pcre_internal.h
594        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
595        their definitions. The declarations used "const uschar *" and the
596        definitions used USPTR. Even though USPTR is normally defined as "const
597        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
598        reported that: "This difference in casting confuses some C++ compilers, for
599        example, SunCC recognizes above declarations as different functions and
600        generates broken code for hbpcre." I have changed the declarations to use
601        USPTR.
603    16. GNU libtool is named differently on some systems. The autogen.sh script now
604        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
605        (FreeBSD).
607    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
608        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
609        comment: "Figure out how to create a longlong from a string: strtoll and
610        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
611        instance, but it only takes 2 args instead of 3!"
613    18. A subtle bug concerned with back references has been fixed by a change of
614        specification, with a corresponding code fix. A pattern such as
615        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
616        refers, was giving matches when it shouldn't. For example, xa=xaaa would
617        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
618        same bug. Such groups have to be quantified to be useful, or contained
619        inside another quantified group. (If there's no repetition, the reference
620        can never match.) The problem arises because, having left the group and
621        moved on to the rest of the pattern, a later failure that backtracks into
622        the group uses the captured value from the final iteration of the group
623        rather than the correct earlier one. I have fixed this in PCRE by forcing
624        any group that contains a reference to itself to be an atomic group; that
625        is, there cannot be any backtracking into it once it has completed. This is
626        similar to recursive and subroutine calls.
629    Version 8.00 19-Oct-09
630    ----------------------
632    1.  The table for translating pcre_compile() error codes into POSIX error codes
633        was out-of-date, and there was no check on the pcre_compile() error code
634        being within the table. This could lead to an OK return being given in
635        error.
637    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
638        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
639        in a Windows environment.
641    3.  The pcregrep --count option prints the count for each file even when it is
642        zero, as does GNU grep. However, pcregrep was also printing all files when
643        --files-with-matches was added. Now, when both options are given, it prints
644        counts only for those files that have at least one match. (GNU grep just
645        prints the file name in this circumstance, but including the count seems
646        more useful - otherwise, why use --count?) Also ensured that the
647        combination -clh just lists non-zero counts, with no names.
649    4.  The long form of the pcregrep -F option was incorrectly implemented as
650        --fixed_strings instead of --fixed-strings. This is an incompatible change,
651        but it seems right to fix it, and I didn't think it was worth preserving
652        the old behaviour.
654    5.  The command line items --regex=pattern and --regexp=pattern were not
655        recognized by pcregrep, which required --regex pattern or --regexp pattern
656        (with a space rather than an '='). The man page documented the '=' forms,
657        which are compatible with GNU grep; these now work.
659    6.  No libpcreposix.pc file was created for pkg-config; there was just
660        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
662    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
663        when UCP support is not needed, by modifying the Python script that
664        generates it from Unicode data files. This should not matter if the module
665        is correctly used as a library, but I received one complaint about 50K of
666        unwanted data. My guess is that the person linked everything into his
667        program rather than using a library. Anyway, it does no harm.
669    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
670        was a minimum greater than 1 for a wide character in a possessive
671        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
672        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
673        character. Chaos in the form of incorrect output or a compiling loop could
674        result.
676    9.  The restrictions on what a pattern can contain when partial matching is
677        requested for pcre_exec() have been removed. All patterns can now be
678        partially matched by this function. In addition, if there are at least two
679        slots in the offset vector, the offset of the earliest inspected character
680        for the match and the offset of the end of the subject are set in them when
681        PCRE_ERROR_PARTIAL is returned.
683    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
684        synonymous with PCRE_PARTIAL, for backwards compatibility, and
685        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
686        and may be more useful for multi-segment matching.
688    11. Partial matching with pcre_exec() is now more intuitive. A partial match
689        used to be given if ever the end of the subject was reached; now it is
690        given only if matching could not proceed because another character was
691        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
692        string "Z", which now yields "no match" instead of "partial match". In the
693        case of pcre_dfa_exec(), "no match" is given if every matching path for the
694        final character ended with (*FAIL).
696    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
697        if the pattern had a "must contain" character that was already found in the
698        earlier partial match, unless partial matching was again requested. For
699        example, with the pattern /dog.(body)?/, the "must contain" character is
700        "g". If the first part-match was for the string "dog", restarting with
701        "sbody" failed. This bug has been fixed.
703    13. The string returned by pcre_dfa_exec() after a partial match has been
704        changed so that it starts at the first inspected character rather than the
705        first character of the match. This makes a difference only if the pattern
706        starts with a lookbehind assertion or \b or \B (\K is not supported by
707        pcre_dfa_exec()). It's an incompatible change, but it makes the two
708        matching functions compatible, and I think it's the right thing to do.
710    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
711        so that the demonstration program is easily available in environments where
712        PCRE has not been installed from source.
714    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
715        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
716        library.
718    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
719        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
720        is not the first non-POSIX option to be added. Clearly some people find
721        these options useful.
723    17. If a caller to the POSIX matching function regexec() passes a non-zero
724        value for nmatch with a NULL value for pmatch, the value of
725        nmatch is forced to zero.
727    18. RunGrepTest did not have a test for the availability of the -u option of
728        the diff command, as RunTest does. It now checks in the same way as
729        RunTest, and also checks for the -b option.
731    19. If an odd number of negated classes containing just a single character
732        interposed, within parentheses, between a forward reference to a named
733        subpattern and the definition of the subpattern, compilation crashed with
734        an internal error, complaining that it could not find the referenced
735        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
736        [The bug was that it was starting one character too far in when skipping
737        over the character class, thus treating the ] as data rather than
738        terminating the class. This meant it could skip too much.]
740    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
741        /g option in pcretest when the pattern contains \K, which makes it possible
742        to have an empty string match not at the start, even when the pattern is
743        anchored. Updated pcretest and pcredemo to use this option.
745    21. If the maximum number of capturing subpatterns in a recursion was greater
746        than the maximum at the outer level, the higher number was returned, but
747        with unset values at the outer level. The correct (outer level) value is
748        now given.
750    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
751        PCRE did not set those parentheses (unlike Perl). I have now found a way to
752        make it do so. The string so far is captured, making this feature
753        compatible with Perl.
755    23. The tests have been re-organized, adding tests 11 and 12, to make it
756        possible to check the Perl 5.10 features against Perl 5.10.
758    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
759        pattern matches a fixed length string. PCRE did not allow this; now it
760        does. Neither allows recursion.
762    25. I finally figured out how to implement a request to provide the minimum
763        length of subject string that was needed in order to match a given pattern.
764        (It was back references and recursion that I had previously got hung up
765        on.) This code has now been added to pcre_study(); it finds a lower bound
766        to the length of subject needed. It is not necessarily the greatest lower
767        bound, but using it to avoid searching strings that are too short does give
768        some useful speed-ups. The value is available to calling programs via
769        pcre_fullinfo().
771    26. While implementing 25, I discovered to my embarrassment that pcretest had
772        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
773        study optimizations had never been tested with that matching function.
774        Oops. What is worse, even when it was passed study data, there was a bug in
775        pcre_dfa_exec() that meant it never actually used it. Double oops. There
776        were also very few tests of studied patterns with pcre_dfa_exec().
778    27. If (?| is used to create subpatterns with duplicate numbers, they are now
779        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
780        on the other side of the coin, they are no longer allowed to have different
781        names, because these cannot be distinguished in PCRE, and this has caused
782        confusion. (This is a difference from Perl.)
784    28. When duplicate subpattern names are present (necessarily with different
785        numbers, as required by 27 above), and a test is made by name in a
786        conditional pattern, either for a subpattern having been matched, or for
787        recursion in such a pattern, all the associated numbered subpatterns are
788        tested, and the overall condition is true if the condition is true for any
789        one of them. This is the way Perl works, and is also more like the way
790        testing by number works.
793    Version 7.9 11-Apr-09
794    ---------------------
796    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
797        (pcretest), all targets were linked against these libraries. This included
798        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
799        libraries. This caused unwanted dependencies to be created. This problem
800        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
801        pcretest is linked with readline.
803    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
804        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
805        moved outside it again, because FALSE and TRUE are already defined in AIX,
806        but BOOL is not.
808    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
809        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
811    4.  The pcregrep documentation said spaces were inserted as well as colons (or
812        hyphens) following file names and line numbers when outputting matching
813        lines. This is not true; no spaces are inserted. I have also clarified the
814        wording for the --colour (or --color) option.
816    5.  In pcregrep, when --colour was used with -o, the list of matching strings
817        was not coloured; this is different to GNU grep, so I have changed it to be
818        the same.
820    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
821        each matching line was coloured. Now it goes on to look for further matches
822        of any of the test patterns, which is the same behaviour as GNU grep.
824    7.  A pattern that could match an empty string could cause pcregrep to loop; it
825        doesn't make sense to accept an empty string match in pcregrep, so I have
826        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
827        seems to be how GNU grep behaves.
829    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
830        start or after a newline", because the conditional assertion was not being
831        correctly handled. The rule now is that both the assertion and what follows
832        in the first alternative must satisfy the test.
834    9.  If auto-callout was enabled in a pattern with a conditional group whose
835        condition was an assertion, PCRE could crash during matching, both with
836        pcre_exec() and pcre_dfa_exec().
838    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
839        used for matching.
841    11. Unicode property support in character classes was not working for
842        characters (bytes) greater than 127 when not in UTF-8 mode.
844    12. Added the -M command line option to pcretest.
846    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
848    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
850    16. Added comments and documentation about mis-use of no_arg in the C++
851        wrapper.
853    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
854        from Martin Jerabek that uses macro names for all relevant character and
855        string constants.
857    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
858        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
859        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
860        these, but not everybody uses configure.
862    19. A conditional group that had only one branch was not being correctly
863        recognized as an item that could match an empty string. This meant that an
864        enclosing group might also not be so recognized, causing infinite looping
865        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
866        with the subject "ab", where knowledge that the repeated group can match
867        nothing is needed in order to break the loop.
869    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
870        exec(), but without supplying a callout function, matching went wrong.
872    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
873        leak if the size of the offset vector was greater than 30. When the vector
874        is smaller, the saved offsets during recursion go onto a local stack
875        vector, but for larger vectors malloc() is used. It was failing to free
876        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
877        error, in fact).
879    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
880        heapframe that is used only when UTF-8 support is enabled. This caused no
881        problem, but was untidy.
883    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
884        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
885        included within another project.
887    24. Steven Van Ingelgem's patches to add more options to the CMake support,
888        slightly modified by me:
890          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
891              not building pcregrep.
893          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
894              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
896    25. Forward references, both numeric and by name, in patterns that made use of
897        duplicate group numbers, could behave incorrectly or give incorrect errors,
898        because when scanning forward to find the reference group, PCRE was not
899        taking into account the duplicate group numbers. A pattern such as
900        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
902    26. Changed a few more instances of "const unsigned char *" to USPTR, making
903        the feature of a custom pointer more persuasive (as requested by a user).
905    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
906        pcretest.c, inside #ifndefs, because it seems they are sometimes already
907        pre-defined.
909    28. Added support for (*UTF8) at the start of a pattern.
911    29. Arrange for flags added by the "release type" setting in CMake to be shown
912        in the configuration summary.
915    Version 7.8 05-Sep-08
916    ---------------------
918    1.  Replaced UCP searching code with optimized version as implemented for Ad
919        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
920        stage table and inline lookup instead of a function, giving speed ups of 2
921        to 5 times on some simple patterns that I tested. Permission was given to
922        distribute the MultiStage2.py script that generates the tables (it's not in
923        the tarball, but is in the Subversion repository).
925    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
926        scripts.
928    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
929        a group with a zero qualifier. The result of the study could be incorrect,
930        or the function might crash, depending on the pattern.
932    4.  Caseless matching was not working for non-ASCII characters in back
933        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
934        It now works when Unicode Property Support is available.
936    5.  In pcretest, an escape such as \x{de} in the data was always generating
937        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
938        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
939        truncation.
941    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
943    7.  Added two (int) casts to pcregrep when printing the difference of two
944        pointers, in case they are 64-bit values.
946    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
947        test 2 if it fails.
949    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
950        and a #define of that name to empty if it is not externally set. This is to
951        allow users of MSVC to set it if necessary.
953    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
954        the convenience functions in the pcre_get.c source file.
956    11. An option change at the start of a pattern that had top-level alternatives
957        could cause overwriting and/or a crash. This command provoked a crash in
958        some environments:
960          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
962        This potential security problem was recorded as CVE-2008-2371.
964    12. For a pattern where the match had to start at the beginning or immediately
965        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
966        pcre_dfa_exec() could read past the end of the passed subject if there was
967        no match. To help with detecting such bugs (e.g. with valgrind), I modified
968        pcretest so that it places the subject at the end of its malloc-ed buffer.
970    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
971        exec() might read past the end of the data buffer in UTF-8 mode.
973    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
974        the data contained the byte 0x85 as part of a UTF-8 character within its
975        first line. This applied both to normal and DFA matching.
977    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
978        /^[^d]*?$/8 failed to match "abc".
980    16. Added a missing copyright notice to pcrecpp_internal.h.
982    17. Make it more clear in the documentation that values returned from
983        pcre_exec() in ovector are byte offsets, not character counts.
985    18. Tidied a few places to stop certain compilers from issuing warnings.
987    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
988        supplied by Stefan Weber. I made a further small update for 7.8 because
989        there is a change of source arrangements: the pcre_searchfuncs.c module is
990        replaced by pcre_ucd.c.
993    Version 7.7 07-May-08
994    ---------------------
996    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
997        a string to a long long, pretend we don't even have a long long." This is
998        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1000    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1001        pre-7.6 versions, which defined a global no_arg variable instead of putting
1002        it in the RE class. (See also #8 below.)
1004    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1005        Lopes.
1007    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1009        (1) The include/exclude patterns were being applied to the whole pathnames
1010            of files, instead of just to the final components.
1012        (2) If there was more than one level of directory, the subdirectories were
1013            skipped unless they satisfied the include/exclude conditions. This is
1014            inconsistent with GNU grep (and could even be seen as contrary to the
1015            pcregrep specification - which I improved to make it absolutely clear).
1016            The action now is always to scan all levels of directory, and just
1017            apply the include/exclude patterns to regular files.
1019    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1020        --exclude_dir in the tests to avoid scanning .svn directories.
1022    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1023        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1024        doesn't support NULs in patterns.
1026    7.  Added some missing "const"s to declarations of static tables in
1027        pcre_compile.c and pcre_dfa_exec.c.
1029    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1030        caused by fix #2  above. (Subsequently also a second patch to fix the
1031        first patch. And a third patch - this was a messy problem.)
1033    9.  Applied Craig's patch to remove the use of push_back().
1035    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1036        matching function regexec().
1038    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1039        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1040        references. PCRE supports relative numbers with this syntax (I don't think
1041        Oniguruma does).
1043    12. Previously, a group with a zero repeat such as (...){0} was completely
1044        omitted from the compiled regex. However, this means that if the group
1045        was called as a subroutine from elsewhere in the pattern, things went wrong
1046        (an internal error was given). Such groups are now left in the compiled
1047        pattern, with a new opcode that causes them to be skipped at execution
1048        time.
1050    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1051        to the way PCRE behaves:
1053        (a) A lone ] character is dis-allowed (Perl treats it as data).
1055        (b) A back reference to an unmatched subpattern matches an empty string
1056            (Perl fails the current match path).
1058        (c) A data ] in a character class must be notated as \] because if the
1059            first data character in a class is ], it defines an empty class. (In
1060            Perl it is not possible to have an empty class.) The empty class []
1061            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1062            The negative empty class [^] matches any one character, independently
1063            of the DOTALL setting.
1065    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1066        non-existent subpattern following a character class starting with ']' and
1067        containing () gave an internal compiling error instead of "reference to
1068        non-existent subpattern". Fortunately, when the pattern did exist, the
1069        compiled code was correct. (When scanning forwards to check for the
1070        existencd of the subpattern, it was treating the data ']' as terminating
1071        the class, so got the count wrong. When actually compiling, the reference
1072        was subsequently set up correctly.)
1074    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1075        it was being rejected as not supported by pcre_dfa_exec(), even though
1076        other assertions are supported. I have made pcre_dfa_exec() support
1077        (*FAIL).
1079    16. The implementation of 13c above involved the invention of a new opcode,
1080        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1081        cannot be changed at match time, I realized I could make a small
1082        improvement to matching performance by compiling OP_ALLANY instead of
1083        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1084        on the OP_ANY path.
1086    17. Compiling pcretest on Windows with readline support failed without the
1087        following two fixes: (1) Make the unistd.h include conditional on
1088        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1090    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1091        ncurses library to be included for pcretest when ReadLine support is
1092        requested, but also to allow for it to be overridden. This patch came from
1093        Daniel Bergström.
1095    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1096        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1097        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1098        spotting this.
1101    Version 7.6 28-Jan-08
1102    ---------------------
1104    1.  A character class containing a very large number of characters with
1105        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1106        overflow.
1108    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1109        HAVE_LONG_LONG is not defined.
1111    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1112        bring them up to date and include new features. This patch includes:
1114        - Fixed PH's badly added libz and libbz2 support.
1115        - Fixed a problem with static linking.
1116        - Added pcredemo. [But later removed - see 7 below.]
1117        - Fixed dftables problem and added an option.
1118        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1119            HAVE_LONG_LONG.
1120        - Added readline support for pcretest.
1121        - Added an listing of the option settings after cmake has run.
1123    4.  A user submitted a patch to Makefile that makes it easy to create
1124        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1125        Makefile.am that cause it to include this special target, without
1126        affecting anything else. Note that the same mingw target plus all
1127        the other distribution libraries and programs are now supported
1128        when configuring with CMake (see 6 below) instead of with
1129        Configure/Make.
1131    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1132        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1133        exported in the Windows port". It has not yet been confirmed that the patch
1134        solves the problem, but it does no harm.
1136    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1137        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1138        with CMake, and also correct the comment about stack recursion.
1140    7.  Remove the automatic building of pcredemo from the ./configure system and
1141        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1142        of a program that users should build themselves after PCRE is installed, so
1143        building it automatically is not really right. What is more, it gave
1144        trouble in some build environments.
1146    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1149    Version 7.5 10-Jan-08
1150    ---------------------
1152    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1153        values in parens when parsing an RE using the C++ wrapper."
1155    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1156        Characters greater than 255 were excluded from the class instead of being
1157        included.
1159    3.  The same bug as (2) above applied to negated POSIX classes such as
1160        [:^space:].
1162    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1163        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1164        I have changed it.
1166    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1167        first named subpattern) and a construct such as (?&a) would reference the
1168        first named subpattern whose name started with "a" (in other words, the
1169        length check was missing). Both these problems are fixed. "Subpattern name
1170        expected" is now given for (?&) (a zero-length name), and this patch also
1171        makes it give the same error for \k'' (previously it complained that that
1172        was a reference to a non-existent subpattern).
1174    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1175        this is right because (?- can be followed by option settings as well as by
1176        digits. I have, however, made the messages clearer.
1178    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1179        than the number used in the conditional) now cause a compile-time error.
1180        This is actually not compatible with Perl, which accepts such patterns, but
1181        treats the conditional as always being FALSE (as PCRE used to), but it
1182        seems to me that giving a diagnostic is better.
1184    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1185        and messages.
1187    9.  Fix two occurrences of "backslash" in comments that should have been
1188        "backspace".
1190    10. Remove two redundant lines of code that can never be obeyed (their function
1191        was moved elsewhere).
1193    11. The program that makes PCRE's Unicode character property table had a bug
1194        which caused it to generate incorrect table entries for sequences of
1195        characters that have the same character type, but are in different scripts.
1196        It amalgamated them into a single range, with the script of the first of
1197        them. In other words, some characters were in the wrong script. There were
1198        thirteen such cases, affecting characters in the following ranges:
1200          U+002b0 - U+002c1
1201          U+0060c - U+0060d
1202          U+0061e - U+00612
1203          U+0064b - U+0065e
1204          U+0074d - U+0076d
1205          U+01800 - U+01805
1206          U+01d00 - U+01d77
1207          U+01d9b - U+01dbf
1208          U+0200b - U+0200f
1209          U+030fc - U+030fe
1210          U+03260 - U+0327f
1211          U+0fb46 - U+0fbb1
1212          U+10450 - U+1049d
1214    12. The -o option (show only the matching part of a line) for pcregrep was not
1215        compatible with GNU grep in that, if there was more than one match in a
1216        line, it showed only the first of them. It now behaves in the same way as
1217        GNU grep.
1219    13. If the -o and -v options were combined for pcregrep, it printed a blank
1220        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1221        does the same. The return code can be used to tell if there were any
1222        non-matching lines.
1224    14. Added --file-offsets and --line-offsets to pcregrep.
1226    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1227        infinitely looping recursion. The bug was that positive lookaheads were not
1228        being skipped when checking for a possible empty match (negative lookaheads
1229        and both kinds of lookbehind were skipped).
1231    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1232        inclusion of <windows.h> to before rather than after the definition of
1233        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1235    17. Specifying a possessive quantifier with a specific limit for a Unicode
1236        character property caused pcre_compile() to compile bad code, which led at
1237        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1238        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1239        caused the error; without that there was no problem.
1241    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1243    19. Added --enable-pcretest-libreadline.
1245    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1246        RE::GlobalReplace(). As a result, the number of replacements returned was
1247        double what it should be. I removed one of the increments, but Craig sent a
1248        later patch that removed the other one (the right fix) and added unit tests
1249        that check the return values (which was not done before).
1251    21. Several CMake things:
1253        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1254            the names libpcre and libpcreposix, not just pcre and pcreposix.
1256        (2) The above change means that pcretest and pcregrep are now correctly
1257            linked with the newly-built libraries, not previously installed ones.
1261    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1262        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1263        UTF-8 newline character). The key issue is that the pattern starts .*;
1264        this means that the match must be either at the beginning, or after a
1265        newline. The bug was in the code for advancing after a failed match and
1266        checking that the new position followed a newline. It was not taking
1267        account of UTF-8 characters correctly.
1269    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1270        character classes. PCRE was not treating the sequence [:...:] as a
1271        character class unless the ... were all letters. Perl, however, seems to
1272        allow any characters between [: and :], though of course it rejects as
1273        unknown any "names" that contain non-letters, because all the known class
1274        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1275        for example, whereas PCRE did not - it did not recognize a POSIX character
1276        class. This seemed a bit dangerous, so the code has been changed to be
1277        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1278        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1279        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1280        Perl does, and where it didn't before.
1282    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1283        Windows environments %n is disabled by default.
1286    Version 7.4 21-Sep-07
1287    ---------------------
1289    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1290        means that a class such as [\s] counted as "explicit reference to CR or
1291        LF". That isn't really right - the whole point of the change was to try to
1292        help when there was an actual mention of one of the two characters. So now
1293        the change happens only if \r or \n (or a literal CR or LF) character is
1294        encountered.
1296    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1297        of both had grown to the point where there were only 3 bits left.
1298        Fortunately, there was spare space in the data structure, and so I have
1299        moved the internal flags into a new 16-bit field to free up more option
1300        bits.
1302    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1303        but did not set the internal JCHANGED flag - either of these is enough to
1304        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1305        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1306        start sets both bits.
1308    4.  Added options (at build time, compile time, exec time) to change \R from
1309        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1311    5.  doc/pcresyntax.html was missing from the distribution.
1313    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1314        compatibility, even though it is no longer used.
1316    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1317        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1318        windows.h file is present (where different names are used). [This was
1319        reversed later after testing - see 16 below.]
1321    8.  Changed all #include <config.h> to #include "config.h". There were also
1322        some further <pcre.h> cases that I changed to "pcre.h".
1324    9.  When pcregrep was used with the --colour option, it missed the line ending
1325        sequence off the lines that it output.
1327    10. It was pointed out to me that arrays of string pointers cause lots of
1328        relocations when a shared library is dynamically loaded. A technique of
1329        using a single long string with a table of offsets can drastically reduce
1330        these. I have refactored PCRE in four places to do this. The result is
1331        dramatic:
1333          Originally:                          290
1334          After changing UCP table:            187
1335          After changing error message table:   43
1336          After changing table of "verbs"       36
1337          After changing table of Posix names   22
1339        Thanks to the folks working on Gregex for glib for this insight.
1341    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1342        unicode-properties was also set.
1344    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1346    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1347        checked only for CRLF.
1349    14. Added casts to pcretest.c to avoid compiler warnings.
1351    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1353    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1354        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1355        entirely. This removes changes made in 7 above.
1357    17. The CMake files have been updated, and there is now more information about
1358        building with CMake in the NON-UNIX-USE document.
1361    Version 7.3 28-Aug-07
1362    ---------------------
1364     1. In the rejigging of the build system that eventually resulted in 7.1, the
1365        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1366        brackets there is not right, since it causes compilers to look for an
1367        installed pcre.h, not the version that is in the source that is being
1368        compiled (which of course may be different). I have changed it back to:
1370          #include "pcre.h"
1372        I have a vague recollection that the change was concerned with compiling in
1373        different directories, but in the new build system, that is taken care of
1374        by the VPATH setting the Makefile.
1376     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1377        when the subject happened to end in the byte 0x85 (e.g. if the last
1378        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1379        characters but of course it shouldn't be taken as a newline when it is part
1380        of another character. The bug was that, for an unlimited repeat of . in
1381        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1382        characters when looking for a newline.
1384     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1386     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1387        in debug output.
1389     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1390        long printing in the pcrecpp unittest when running under MinGW.
1392     6. ESC_K was left out of the EBCDIC table.
1394     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1395        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1396        limit also applies to "virtual nesting" when a pattern is recursive, and in
1397        this case 1000 isn't so big. I have been able to remove this limit at the
1398        expense of backing off one optimization in certain circumstances. Normally,
1399        when pcre_exec() would call its internal match() function recursively and
1400        immediately return the result unconditionally, it uses a "tail recursion"
1401        feature to save stack. However, when a subpattern that can match an empty
1402        string has an unlimited repetition quantifier, it no longer makes this
1403        optimization. That gives it a stack frame in which to save the data for
1404        checking that an empty string has been matched. Previously this was taken
1405        from the 1000-entry workspace that had been reserved. So now there is no
1406        explicit limit, but more stack is used.
1408     8. Applied Daniel's patches to solve problems with the import/export magic
1409        syntax that is required for Windows, and which was going wrong for the
1410        pcreposix and pcrecpp parts of the library. These were overlooked when this
1411        problem was solved for the main library.
1413     9. There were some crude static tests to avoid integer overflow when computing
1414        the size of patterns that contain repeated groups with explicit upper
1415        limits. As the maximum quantifier is 65535, the maximum group length was
1416        set at 30,000 so that the product of these two numbers did not overflow a
1417        32-bit integer. However, it turns out that people want to use groups that
1418        are longer than 30,000 bytes (though not repeat them that many times).
1419        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1420        made it possible to implement the integer overflow checks in a much more
1421        dynamic way, which I have now done. The artificial limitation on group
1422        length has been removed - we now have only the limit on the total length of
1423        the compiled pattern, which depends on the LINK_SIZE setting.
1425    10. Fixed a bug in the documentation for get/copy named substring when
1426        duplicate names are permitted. If none of the named substrings are set, the
1427        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1428        empty string.
1430    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1431        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1432        because the ] is interpreted as the first data character and the
1433        terminating ] is not found. PCRE has been made compatible with Perl in this
1434        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1435        cause memory overwriting.
1437    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1438        string has been matched (to stop an infinite loop). It was not recognizing
1439        a conditional subpattern that could match an empty string if that
1440        subpattern was within another subpattern. For example, it looped when
1441        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1442        condition was not nested. This bug has been fixed.
1444    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1445        past the start of the subject in the presence of bytes with the top bit
1446        set, for example "\x8aBCD".
1448    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1449        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1451    14. Optimized (?!) to (*FAIL).
1453    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1454        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1455        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1456        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1457        does: it's just the validity check that is more restrictive.
1459    16. Inserted checks for integer overflows during escape sequence (backslash)
1460        processing, and also fixed erroneous offset values for syntax errors during
1461        backslash processing.
1463    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1464        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1466    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1467        caused an overrun.
1469    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1470        something other than just ASCII characters) inside a group that had an
1471        unlimited repeat caused a loop at compile time (while checking to see
1472        whether the group could match an empty string).
1474    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1475        [\P{Any}] did so. (Error in the code for printing property names.)
1477    21. An orphan \E inside a character class could cause a crash.
1479    22. A repeated capturing bracket such as (A)? could cause a wild memory
1480        reference during compilation.
1482    23. There are several functions in pcre_compile() that scan along a compiled
1483        expression for various reasons (e.g. to see if it's fixed length for look
1484        behind). There were bugs in these functions when a repeated \p or \P was
1485        present in the pattern. These operators have additional parameters compared
1486        with \d, etc, and these were not being taken into account when moving along
1487        the compiled data. Specifically:
1489        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1490            length.
1492        (b) An item such as \pL+ within a repeated group could cause crashes or
1493            loops.
1495        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1496            "reference to non-existent subpattern" error.
1498        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1500    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1501        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1503    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1505    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1506        character were causing crashes (broken optimization).
1508    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1509        \p or \P) caused a compile-time loop.
1511    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1512        break. For example, the unstudied pattern [\r\n]A does not match the string
1513        "\r\nA" because change 7.0/46 below moves the current point on by two
1514        characters after failing to match at the start. However, the pattern \nA
1515        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1516        the same is true. There doesn't seem any very clean way out of this, but
1517        what I have chosen to do makes the common cases work: PCRE now takes note
1518        of whether there can be an explicit match for \r or \n anywhere in the
1519        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1520        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1521        pattern has explicit CR or LF references.
1523    29. Added (*CR) etc for changing newline setting at start of pattern.
1526    Version 7.2 19-Jun-07
1527    ---------------------
1529     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1530        which is apparently normally available under Windows.
1532     2. Re-jig the pcregrep tests with different newline settings in an attempt
1533        to make them independent of the local environment's newline setting.
1535     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1537     4. Some of the "internals" tests were previously cut out when the link size
1538        was not 2, because the output contained actual offsets. The recent new
1539        "Z" feature of pcretest means that these can be cut out, making the tests
1540        usable with all link sizes.
1542     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1543        stack recursion. This gives a massive performance boost under BSD, but just
1544        a small improvement under Linux. However, it saves one field in the frame
1545        in all cases.
1547     6. Added more features from the forthcoming Perl 5.10:
1549        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1550            recursion call. It refers to the nth most recently opened parentheses.
1552        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1553            to be opened parentheses.
1555        (c) Conditions that refer to capturing parentheses can be specified
1556            relatively, for example, (?(-2)... or (?(+3)...
1558        (d) \K resets the start of the current match so that everything before
1559            is not part of it.
1561        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1563        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1564            reference syntax.
1566        (g) (?| introduces a group in which the numbering of parentheses in each
1567            alternative starts with the same number.
1569        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1571     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1574     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1575        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1576        for detecting groups that can match an empty string.
1578     9. A pattern with a very large number of alternatives (more than several
1579        hundred) was running out of internal workspace during the pre-compile
1580        phase, where pcre_compile() figures out how much memory will be needed. A
1581        bit of new cunning has reduced the workspace needed for groups with
1582        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1583        workspace instead of running out of the 4096 that are available.
1585    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1587    11. Applied patch from Google to remove an optimization that didn't quite work.
1588        The report of the bug said:
1590          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1591          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1592          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1594    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1595        it matched the wrong number of bytes.
1598    Version 7.1 24-Apr-07
1599    ---------------------
1601     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1602        that is more "standard", making use of automake and other Autotools. There
1603        is some re-arrangement of the files and adjustment of comments consequent
1604        on this.
1606     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1607        for recursive directory scanning broke on some systems because the files
1608        are not scanned in any specific order and on different systems the order
1609        was different. A call to "sort" has been inserted into RunGrepTest for the
1610        approprate test as a short-term fix. In the longer term there may be an
1611        alternative.
1613     3. I had an email from Eric Raymond about problems translating some of PCRE's
1614        man pages to HTML (despite the fact that I distribute HTML pages, some
1615        people do their own conversions for various reasons). The problems
1616        concerned the use of low-level troff macros .br and .in. I have therefore
1617        removed all such uses from the man pages (some were redundant, some could
1618        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1619        HTML has been updated to handle .nf/.fi and to complain if it encounters
1620        .br or .in.
1622     4. Updated comments in configure.ac that get placed in config.h.in and also
1623        arranged for config.h to be included in the distribution, with the name
1624        config.h.generic, for the benefit of those who have to compile without
1625        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1627     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1628        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1629        makevp.bat for the current PCRE, using the additional files
1630        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1632     6. A Windows user reported a minor discrepancy with test 2, which turned out
1633        to be caused by a trailing space on an input line that had got lost in his
1634        copy. The trailing space was an accident, so I've just removed it.
1636     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1637        that is needed.
1639     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1640        as "const" (a) because they are and (b) because it helps the PHP
1641        maintainers who have recently made a script to detect big data structures
1642        in the php code that should be moved to the .rodata section. I remembered
1643        to update Builducptable as well, so it won't revert if ucptable.h is ever
1644        re-created.
1646     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1647        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1648        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1649        support is not required. This saves 1.5-2K of code, which is important in
1650        some applications.
1652        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1653        so as not to refer to the tables, even though these functions will never be
1654        called when UTF-8 support is disabled. Otherwise there are problems with a
1655        shared library.
1657    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1659        (a) It was defining its arguments as char * instead of void *.
1661        (b) It was assuming that all moves were upwards in memory; this was true
1662            a long time ago when I wrote it, but is no longer the case.
1664        The emulated memove() is provided for those environments that have neither
1665        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1666        is clearly not the case, as these two bugs were recently reported.
1668    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1669        and Detrail to create the HTML documentation, the .txt form of the man
1670        pages, and it removes trailing spaces from listed files. It also creates
1671        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1672        case, it wraps all the #defines with #ifndefs. This script should be run
1673        before "make dist".
1675    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1676        with Unicode property support.
1678        (a) For a maximizing quantifier, if the two different cases of the
1679            character were of different lengths in their UTF-8 codings (there are
1680            some cases like this - I found 11), and the matching function had to
1681            back up over a mixture of the two cases, it incorrectly assumed they
1682            were both the same length.
1684        (b) When PCRE was configured to use the heap rather than the stack for
1685            recursion during matching, it was not correctly preserving the data for
1686            the other case of a UTF-8 character when checking ahead for a match
1687            while processing a minimizing repeat. If the check also involved
1688            matching a wide character, but failed, corruption could cause an
1689            erroneous result when trying to check for a repeat of the original
1690            character.
1692    13. Some tidying changes to the testing mechanism:
1694        (a) The RunTest script now detects the internal link size and whether there
1695            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1696            values substituted by "configure". (The RunGrepTest script already did
1697            this for UTF-8.) The configure.ac script no longer substitutes the
1698            relevant variables.
1700        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1701            with length and offset values. This means that the output is different
1702            for different internal link sizes. Test 2 is skipped for link sizes
1703            other than 2 because of this, bypassing the problem. Unfortunately,
1704            there was also a test in test 3 (the locale tests) that used /B and
1705            failed for link sizes other than 2. Rather than cut the whole test out,
1706            I have added a new /Z option to pcretest that replaces the length and
1707            offset values with spaces. This is now used to make test 3 independent
1708            of link size. (Test 2 will be tidied up later.)
1710    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1711        segmentation fault instead of returning the appropriate error message.
1713    15. In multiline mode when the newline sequence was set to "any", the pattern
1714        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1715        This doesn't seem right; it now treats the CRLF combination as the line
1716        ending, and so does not match in that case. It's only a pattern such as ^$
1717        that would hit this one: something like ^ABC$ would have failed after \r
1718        and then tried again after \r\n.
1720    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1721        in an attempt to make files that differ only in their line terminators
1722        compare equal. This works on Linux.
1724    17. Under certain error circumstances pcregrep might try to free random memory
1725        as it exited. This is now fixed, thanks to valgrind.
1727    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1728        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1729        was because its rules for how to advance for /g after matching an empty
1730        string at the end of a line did not allow for this case. They now check for
1731        it specially.
1733    20. pcretest is supposed to handle patterns and data of any length, by
1734        extending its buffers when necessary. It was getting this wrong when the
1735        buffer for a data line had to be extended.
1737    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1738        CRLF as a newline sequence.
1740    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1741        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1742        I have nevertheless tidied it up.
1744    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1746    24. Added a man page for pcre-config.
1749    Version 7.0 19-Dec-06
1750    ---------------------
1752     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1753        moving to gcc 4.1.1.
1755     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1756        sys/time.h, which is documented as needed for this function. It doesn't
1757        seem to matter on Linux, but it showed up on some releases of OS X.
1759     3. It seems that there are systems where bytes whose values are greater than
1760        127 match isprint() in the "C" locale. The "C" locale should be the
1761        default when a C program starts up. In most systems, only ASCII printing
1762        characters match isprint(). This difference caused the output from pcretest
1763        to vary, making some of the tests fail. I have changed pcretest so that:
1765        (a) When it is outputting text in the compiled version of a pattern, bytes
1766            other than 32-126 are always shown as hex escapes.
1768        (b) When it is outputting text that is a matched part of a subject string,
1769            it does the same, unless a different locale has been set for the match
1770            (using the /L modifier). In this case, it uses isprint() to decide.
1772     4. Fixed a major bug that caused incorrect computation of the amount of memory
1773        required for a compiled pattern when options that changed within the
1774        pattern affected the logic of the preliminary scan that determines the
1775        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1776        that the computed length was too small. The symptoms of this bug were
1777        either the PCRE error "internal error: code overflow" from pcre_compile(),
1778        or a glibc crash with a message such as "pcretest: free(): invalid next
1779        size (fast)". Examples of patterns that provoked this bug (shown in
1780        pcretest format) are:
1782          /(?-x: )/x
1783          /(?x)(?-x: \s*#\s*)/
1784          /((?i)[\x{c0}])/8
1785          /(?i:[\x{c0}])/8
1787        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1788        is now done differently.
1790     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1791        wrapper classes; (b) implement a new function in the C++ scanner that is
1792        more efficient than the old way of doing things because it avoids levels of
1793        recursion in the regex matching; (c) add a paragraph to the documentation
1794        for the FullMatch() function.
1796     6. The escape sequence \n was being treated as whatever was defined as
1797        "newline". Not only was this contrary to the documentation, which states
1798        that \n is character 10 (hex 0A), but it also went horribly wrong when
1799        "newline" was defined as CRLF. This has been fixed.
1801     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1802        was being set to -1 for the "end of line" case (supposedly a value that no
1803        character can have). Though this value is never used (the check for end of
1804        line is "zero bytes in current character"), it caused compiler complaints.
1805        I've changed it to 0xffffffff.
1807     8. In pcre_version.c, the version string was being built by a sequence of
1808        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1809        string (as it is for production releases) called a macro with an empty
1810        argument. The C standard says the result of this is undefined. The gcc
1811        compiler treats it as an empty string (which was what was wanted) but it is
1812        reported that Visual C gives an error. The source has been hacked around to
1813        avoid this problem.
1815     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1816        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1817        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1818        of them did).
1820    10. Originally, pcretest opened its input and output without "b"; then I was
1821        told that "b" was needed in some environments, so it was added for release
1822        5.0 to both the input and output. (It makes no difference on Unix-like
1823        systems.) Later I was told that it is wrong for the input on Windows. I've
1824        now abstracted the modes into two macros, to make it easier to fiddle with
1825        them, and removed "b" from the input mode under Windows.
1827    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1829    12. Added -help and --help to pcretest as an official way of being reminded
1830        of the options.
1832    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1833        and pcrecpp.cc because they annoy compilers at high warning levels.
1835    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1837    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1838        scripts are not C programs :-) and which was not noticed because it works
1839        on Linux.
1841    16. pcretest is supposed to handle any length of pattern and data line (as one
1842        line or as a continued sequence of lines) by extending its input buffer if
1843        necessary. This feature was broken for very long pattern lines, leading to
1844        a string of junk being passed to pcre_compile() if the pattern was longer
1845        than about 50K.
1847    17. I have done a major re-factoring of the way pcre_compile() computes the
1848        amount of memory needed for a compiled pattern. Previously, there was code
1849        that made a preliminary scan of the pattern in order to do this. That was
1850        OK when PCRE was new, but as the facilities have expanded, it has become
1851        harder and harder to keep it in step with the real compile phase, and there
1852        have been a number of bugs (see for example, 4 above). I have now found a
1853        cunning way of running the real compile function in a "fake" mode that
1854        enables it to compute how much memory it would need, while actually only
1855        ever using a few hundred bytes of working memory and without too many
1856        tests of the mode. This should make future maintenance and development
1857        easier. A side effect of this work is that the limit of 200 on the nesting
1858        depth of parentheses has been removed (though this was never a serious
1859        limitation, I suspect). However, there is a downside: pcre_compile() now
1860        runs more slowly than before (30% or more, depending on the pattern). I
1861        hope this isn't a big issue. There is no effect on runtime performance.
1863    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1864        newline (only possible for the last line of a file) and it was a
1865        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1867    19. Added additional timing features to pcretest. (1) The -tm option now times
1868        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1869        separate command line item, by a number that specifies the number of
1870        repeats to use when timing. The default is 50000; this gives better
1871        precision, but takes uncomfortably long for very large patterns.
1873    20. Extended pcre_study() to be more clever in cases where a branch of a
1874        subpattern has no definite first character. For example, (a*|b*)[cd] would
1875        previously give no result from pcre_study(). Now it recognizes that the
1876        first character must be a, b, c, or d.
1878    21. There was an incorrect error "recursive call could loop indefinitely" if
1879        a subpattern (or the entire pattern) that was being tested for matching an
1880        empty string contained only one non-empty item after a nested subpattern.
1881        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1882        incorrectly, because the \d was being skipped in the check.
1884    22. The pcretest program now has a new pattern option /B and a command line
1885        option -b, which is equivalent to adding /B to every pattern. This causes
1886        it to show the compiled bytecode, without the additional information that
1887        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1888        is the same as /B/I).
1890    23. A new optimization is now able automatically to treat some sequences such
1891        as a*b as a*+b. More specifically, if something simple (such as a character
1892        or a simple class like \d) has an unlimited quantifier, and is followed by
1893        something that cannot possibly match the quantified thing, the quantifier
1894        is automatically "possessified".
1896    24. A recursive reference to a subpattern whose number was greater than 39
1897        went wrong under certain circumstances in UTF-8 mode. This bug could also
1898        have affected the operation of pcre_study().
1900    25. Realized that a little bit of performance could be had by replacing
1901        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1903    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1905    27. Possessive quantifiers such as a++ were previously implemented by turning
1906        them into atomic groups such as ($>a+). Now they have their own opcodes,
1907        which improves performance. This includes the automatically created ones
1908        from 23 above.
1910    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1911        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1912        the first matched character to be a colon. This applied both to named and
1913        numbered groups.
1915    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1917    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1918        building PCRE on Windows easier, so I have included it in the distribution.
1920    31. There is now a check in pcretest against a ridiculously large number being
1921        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1922        loop, the loop is abandoned.
1924    32. Forward references to subpatterns in conditions such as (?(2)...) where
1925        subpattern 2 is defined later cause pcre_compile() to search forwards in
1926        the pattern for the relevant set of parentheses. This search went wrong
1927        when there were unescaped parentheses in a character class, parentheses
1928        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1930    33. "Subroutine" calls and backreferences were previously restricted to
1931        referencing subpatterns earlier in the regex. This restriction has now
1932        been removed.
1934    34. Added a number of extra features that are going to be in Perl 5.10. On the
1935        whole, these are just syntactic alternatives for features that PCRE had
1936        previously implemented using the Python syntax or my own invention. The
1937        other formats are all retained for compatibility.
1939        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1940            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1941            also .NET compatible.
1943        (b) A recursion or subroutine call to a named group can now be defined as
1944            (?&name) as well as (?P>name).
1946        (c) A backreference to a named group can now be defined as \k<name> or
1947            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1948            5.10, are also .NET compatible.
1950        (d) A conditional reference to a named group can now use the syntax
1951            (?(<name>) or (?('name') as well as (?(name).
1953        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1954            groups (named and numbered) that are never evaluated inline, but can be
1955            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1956            is always false. There may be only one alternative in such a group.
1958        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1959            as the simple (?(R). The condition is true only if the most recent
1960            recursion is that of the given number or name. It does not search out
1961            through the entire recursion stack.
1963        (g) The escape \gN or \g{N} has been added, where N is a positive or
1964            negative number, specifying an absolute or relative reference.
1966    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1967        some "unreachable code" warnings.
1969    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1970        things, this adds five new scripts.
1972    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1973        There were also incompatibilities regarding the handling of \Q..\E inside
1974        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1975        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1977    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1978        matches an empty string, and forcibly breaks the loop. There were bugs in
1979        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1980        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1981        separate and independent bugs (that affected different cases) have been
1982        fixed.
1984    39. Refactored the code to abolish the use of different opcodes for small
1985        capturing bracket numbers. This is a tidy that I avoided doing when I
1986        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1987        The new approach is not only tidier, it makes it possible to reduce the
1988        memory needed to fix the previous bug (38).
1990    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1991        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1992        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1993        mode.
1995    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1996        report.
1998    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1999        copy construction and assignment in the C++ wrapper.
2001    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2002        couple of bugs that could have given wrong results in the "--newline=crlf"
2003        case.
2005    44. Added a number of casts and did some reorganization of signed/unsigned int
2006        variables following suggestions from Dair Grant. Also renamed the variable
2007        "this" as "item" because it is a C++ keyword.
2009    45. Arranged for dftables to add
2011          #include "pcre_internal.h"
2013        to pcre_chartables.c because without it, gcc 4.x may remove the array
2014        definition from the final binary if PCRE is built into a static library and
2015        dead code stripping is activated.
2017    46. For an unanchored pattern, if a match attempt fails at the start of a
2018        newline sequence, and the newline setting is CRLF or ANY, and the next two
2019        characters are CRLF, advance by two characters instead of one.
2022    Version 6.7 04-Jul-06
2023    ---------------------
2025     1. In order to handle tests when input lines are enormously long, pcretest has
2026        been re-factored so that it automatically extends its buffers when
2027        necessary. The code is crude, but this _is_ just a test program. The
2028        default size has been increased from 32K to 50K.
2030     2. The code in pcre_study() was using the value of the re argument before
2031        testing it for NULL. (Of course, in any sensible call of the function, it
2032        won't be NULL.)
2034     3. The memmove() emulation function in pcre_internal.h, which is used on
2035        systems that lack both memmove() and bcopy() - that is, hardly ever -
2036        was missing a "static" storage class specifier.
2038     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2039        containing an extended class (one that cannot be represented by a bitmap
2040        because it contains high-valued characters or Unicode property items, e.g.
2041        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2042        pattern, but PCRE should not loop if you do not (it no longer does).
2043        [Detail: two cases were found: (a) a repeated subpattern containing an
2044        extended class; (b) a recursive reference to a subpattern that followed a
2045        previous extended class. It wasn't skipping over the extended class
2046        correctly when UTF-8 mode was not set.]
2048     5. A negated single-character class was not being recognized as fixed-length
2049        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2050        compile error "lookbehind assertion is not fixed length".
2052     6. The RunPerlTest auxiliary script was showing an unexpected difference
2053        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2054        write a Perl script that can interpret lines of an input file either as
2055        byte characters or as UTF-8, which is what "perltest" was being required to
2056        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2057        can't do is switch easily at run time between having the "use utf8;" pragma
2058        or not. In the end, I fudged it by using the RunPerlTest script to insert
2059        "use utf8;" explicitly for the UTF-8 tests.
2061     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2062        the end of the subject string, contrary to the documentation and to what
2063        Perl does. This was true of both matching functions. Now it matches only at
2064        the start of the subject and immediately after *internal* newlines.
2066     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2067        a pointer to an int instead of a pointer to an unsigned long int. This
2068        caused problems on 64-bit systems.
2070     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2071        instance of the 'standard' template library not being so standard".
2073    10. There was no check on the number of named subpatterns nor the maximum
2074        length of a subpattern name. The product of these values is used to compute
2075        the size of the memory block for a compiled pattern. By supplying a very
2076        long subpattern name and a large number of named subpatterns, the size
2077        computation could be caused to overflow. This is now prevented by limiting
2078        the length of names to 32 characters, and the number of named subpatterns
2079        to 10,000.
2081    11. Subpatterns that are repeated with specific counts have to be replicated in
2082        the compiled pattern. The size of memory for this was computed from the
2083        length of the subpattern and the repeat count. The latter is limited to
2084        65535, but there was no limit on the former, meaning that integer overflow
2085        could in principle occur. The compiled length of a repeated subpattern is
2086        now limited to 30,000 bytes in order to prevent this.
2088    12. Added the optional facility to have named substrings with the same name.
2090    13. Added the ability to use a named substring as a condition, using the
2091        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2092        are numbers (not recommended). Forward references are permitted.
2094    14. Added forward references in named backreferences (if you see what I mean).
2096    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2097        pattern could run off the end of the subject. For example, the pattern
2098        "(?s)(.{1,5})"8 did this with the subject "ab".
2100    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2101        PCRE_CASELESS was set when matching characters that were quantified with ?
2102        or *.
2104    17. A character class other than a single negated character that had a minimum
2105        but no maximum quantifier - for example [ab]{6,} - was not handled
2106        correctly by pce_dfa_exec(). It would match only one character.
2108    18. A valid (though odd) pattern that looked like a POSIX character
2109        class but used an invalid character after [ (for example [[,abc,]]) caused
2110        pcre_compile() to give the error "Failed: internal error: code overflow" or
2111        in some cases to crash with a glibc free() error. This could even happen if
2112        the pattern terminated after [[ but there just happened to be a sequence of
2113        letters, a binary zero, and a closing ] in the memory that followed.
2115    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2116        over the years. Originally (before any Unicode support), just the bottom 8
2117        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2118        output from "man perlunicode" includes this:
2120          The regular expression compiler produces polymorphic opcodes.  That
2121          is, the pattern adapts to the data and automatically switches to
2122          the Unicode character scheme when presented with Unicode data--or
2123          instead uses a traditional byte scheme when presented with byte
2124          data.
2126        Sadly, a wide octal escape does not cause a switch, and in a string with
2127        no other multibyte characters, these octal escapes are treated as before.
2128        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2129        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2130        Unicode string.
2132        I have not perpetrated such confusion in PCRE. Up till now, it took just
2133        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2134        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2135        translate to the appropriate multibyte character.
2137    29. Applied some refactoring to reduce the number of warnings from Microsoft
2138        and Borland compilers. This has included removing the fudge introduced
2139        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2140        a warning about an unused variable.
2142    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2143        characters since release 4.0, because Perl (from release 5.004) does not.
2144        [Or at least, is documented not to: some releases seem to be in conflict
2145        with the documentation.] However, when a pattern was studied with
2146        pcre_study() and all its branches started with \s, PCRE still included VT
2147        as a possible starting character. Of course, this did no harm; it just
2148        caused an unnecessary match attempt.
2150    22. Removed a now-redundant internal flag bit that recorded the fact that case
2151        dependency changed within the pattern. This was once needed for "required
2152        byte" processing, but is no longer used. This recovers a now-scarce options
2153        bit. Also moved the least significant internal flag bit to the most-
2154        significant bit of the word, which was not previously used (hangover from
2155        the days when it was an int rather than a uint) to free up another bit for
2156        the future.
2158    23. Added support for CRLF line endings as well as CR and LF. As well as the
2159        default being selectable at build time, it can now be changed at runtime
2160        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2161        specify that it is scanning data with non-default line endings.
2163    24. Changed the definition of CXXLINK to make it agree with the definition of
2164        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2166    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2167        recursions. This makes a big different to stack usage for some patterns.
2169    26. If a subpattern containing a named recursion or subroutine reference such
2170        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2171        the space required for the compiled pattern went wrong and gave too small a
2172        value. Depending on the environment, this could lead to "Failed: internal
2173        error: code overflow at offset 49" or "glibc detected double free or
2174        corruption" errors.
2176    27. Applied patches from Google (a) to support the new newline modes and (b) to
2177        advance over multibyte UTF-8 characters in GlobalReplace.
2179    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2180        difference for some implementation of PCRE in some Windows version.
2182    29. Added some extra testing facilities to pcretest:
2184        \q<number>   in a data line sets the "match limit" value
2185        \Q<number>   in a data line sets the "match recursion limt" value
2186        -S <number>  sets the stack size, where <number> is in megabytes
2188        The -S option isn't available for Windows.
2191    Version 6.6 06-Feb-06
2192    ---------------------
2194     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2195        in pcreposix.h. I have copied the definition from pcre.h.
2197     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2198        because pcre.h is no longer a built file.
2200     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2201        not normally included in the compiled code.
2204    Version 6.5 01-Feb-06
2205    ---------------------
2207     1. When using the partial match feature with pcre_dfa_exec(), it was not
2208        anchoring the second and subsequent partial matches at the new starting
2209        point. This could lead to incorrect results. For example, with the pattern
2210        /1234/, partially matching against "123" and then "a4" gave a match.
2212     2. Changes to pcregrep:
2214        (a) All non-match returns from pcre_exec() were being treated as failures
2215            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2216            error message is output. Some extra information is given for the
2217            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2218            probably the only errors that are likely to be caused by users (by
2219            specifying a regex that has nested indefinite repeats, for instance).
2220            If there are more than 20 of these errors, pcregrep is abandoned.
2222        (b) A binary zero was treated as data while matching, but terminated the
2223            output line if it was written out. This has been fixed: binary zeroes
2224            are now no different to any other data bytes.
2226        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2227            used to set a locale for matching. The --locale=xxxx long option has
2228            been added (no short equivalent) to specify a locale explicitly on the
2229            pcregrep command, overriding the environment variables.
2231        (d) When -B was used with -n, some line numbers in the output were one less
2232            than they should have been.
2234        (e) Added the -o (--only-matching) option.
2236        (f) If -A or -C was used with -c (count only), some lines of context were
2237            accidentally printed for the final match.
2239        (g) Added the -H (--with-filename) option.
2241        (h) The combination of options -rh failed to suppress file names for files
2242            that were found from directory arguments.
2244        (i) Added the -D (--devices) and -d (--directories) options.
2246        (j) Added the -F (--fixed-strings) option.
2248        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2250        (l) Added the --colo(u)r option.
2252        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2253            is not present by default.
2255     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2256        items such as (?R) or (?1), when the recursion could match a number of
2257        alternatives. If it matched one of the alternatives, but subsequently,
2258        outside the recursion, there was a failure, the code tried to back up into
2259        the recursion. However, because of the way PCRE is implemented, this is not
2260        possible, and the result was an incorrect result from the match.
2262        In order to prevent this happening, the specification of recursion has
2263        been changed so that all such subpatterns are automatically treated as
2264        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2266     4. I had overlooked the fact that, in some locales, there are characters for
2267        which isalpha() is true but neither isupper() nor islower() are true. In
2268        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2269        and ordfeminine) are like this. This affected the treatment of \w and \W
2270        when they appeared in character classes, but not when they appeared outside
2271        a character class. The bit map for "word" characters is now created
2272        separately from the results of isalnum() instead of just taking it from the
2273        upper, lower, and digit maps. (Plus the underscore character, of course.)
2275     5. The above bug also affected the handling of POSIX character classes such as
2276        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2277        permanent tables. Instead, the bit maps for such a class were previously
2278        created as the appropriate unions of the upper, lower, and digit bitmaps.
2279        Now they are created by subtraction from the [[:word:]] class, which has
2280        its own bitmap.
2282     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2283        It is created by subtracting the vertical space characters (\x09, \x0a,
2284        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2285        subtraction was done in the overall bitmap for a character class, meaning
2286        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2287        be recognized. This bug has been fixed.
2289     7. Patches from the folks at Google:
2291          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2292          real life, but is still worth protecting against".
2294          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2295          regular expressions".
2297          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2298          have it.
2300          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2301          "configure" and the latter not, in order to fix a problem somebody had
2302          with compiling the Arg class on HP-UX.
2304          (e) Improve the error-handling of the C++ wrapper a little bit.
2306          (f) New tests for checking recursion limiting.
2308     8. The pcre_memmove() function, which is used only if the environment does not
2309        have a standard memmove() function (and is therefore rarely compiled),
2310        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2311        returning a result (though PCRE never actually uses the result).
2313     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2314        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2315        returned instead of calling malloc() with an overflowing number that would
2316        most likely cause subsequent chaos.
2318    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2320    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2321        with this option is matched, the nmatch and pmatch options of regexec() are
2322        ignored.
2324    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2325        provided in case anyone wants to the the POSIX interface with UTF-8
2326        strings.
2328    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2329        C++ linking (needed for some HP-UX environments).
2331    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2332        (unused parameter) and in the pcre_printint() function (omitted "default"
2333        switch label when the default is to do nothing).
2335    15. Added some code to make it possible, when PCRE is compiled as a C++
2336        library, to replace subject pointers for pcre_exec() with a smart pointer
2337        class, thus making it possible to process discontinuous strings.
2339    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2340        much the same function. They were added by different people who were trying
2341        to make PCRE easy to compile on non-Unix systems. It has been suggested
2342        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2343        for compiling on Windows systems. I have therefore replaced it with
2344        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2345        defaults to "extern" for C or "extern C" for C++, which works fine on
2346        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2347        SCOPE with something explicit in config.h. In addition:
2349        (a) pcreposix.h still had just "extern" instead of either of these macros;
2350            I have replaced it with PCRE_DATA_SCOPE.
2352        (b) Functions such as _pcre_xclass(), which are internal to the library,
2353            but external in the C sense, all had PCRE_EXPORT in their definitions.
2354            This is apparently wrong for the Windows case, so I have removed it.
2355            (It makes no difference on Unix-like systems.)
2357    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2358        of recursive calls to match(). This is different to MATCH_LIMIT because
2359        that limits the total number of calls to match(), not all of which increase
2360        the depth of recursion. Limiting the recursion depth limits the amount of
2361        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2362        when PCRE is compiled, and changed at run time. A patch from Google adds
2363        this functionality to the C++ interface.
2365    18. Changes to the handling of Unicode character properties:
2367        (a) Updated the table to Unicode 4.1.0.
2369        (b) Recognize characters that are not in the table as "Cn" (undefined).
2371        (c) I revised the way the table is implemented to a much improved format
2372            which includes recognition of ranges. It now supports the ranges that
2373            are defined in UnicodeData.txt, and it also amalgamates other
2374            characters into ranges. This has reduced the number of entries in the
2375            table from around 16,000 to around 3,000, thus reducing its size
2376            considerably. I realized I did not need to use a tree structure after
2377            all - a binary chop search is just as efficient. Having reduced the
2378            number of entries, I extended their size from 6 bytes to 8 bytes to
2379            allow for more data.
2381        (d) Added support for Unicode script names via properties such as \p{Han}.
2383    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2384        matching that character.
2386    20. When matching a repeated Unicode property with a minimum greater than zero,
2387        (for example \pL{2,}), PCRE could look past the end of the subject if it
2388        reached it while seeking the minimum number of characters. This could
2389        happen only if some of the characters were more than one byte long, because
2390        there is a check for at least the minimum number of bytes.
2392    21. Refactored the implementation of \p and \P so as to be more general, to
2393        allow for more different types of property in future. This has changed the
2394        compiled form incompatibly. Anybody with saved compiled patterns that use
2395        \p or \P will have to recompile them.
2397    22. Added "Any" and "L&" to the supported property types.
2399    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2400        but give a compile time error if the value is greater than 0xff.
2402    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2403        accidentally not being installed or uninstalled.
2405    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2406        made were to insert the current release number. This seemed silly, because
2407        it made things harder for people building PCRE on systems that don't run
2408        "configure". I have turned pcre.h into a distributed file, no longer built
2409        by "configure", with the version identification directly included. There is
2410        no longer a pcre.h.in file.
2412        However, this change necessitated a change to the pcre-config script as
2413        well. It is built from pcre-config.in, and one of the substitutions was the
2414        release number. I have updated configure.ac so that ./configure now finds
2415        the release number by grepping pcre.h.
2417    26. Added the ability to run the tests under valgrind.
2420    Version 6.4 05-Sep-05
2421    ---------------------
2423     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2424        "--" to be printed when multiple files were scanned, even when none of the
2425        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2426        consider it to be a bug, and have restored the previous behaviour.
2428     2. A couple of code tidies to get rid of compiler warnings.
2430     3. The pcretest program used to cheat by referring to symbols in the library
2431        whose names begin with _pcre_. These are internal symbols that are not
2432        really supposed to be visible externally, and in some environments it is
2433        possible to suppress them. The cheating is now confined to including
2434        certain files from the library's source, which is a bit cleaner.
2436     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2437        file's purpose clearer.
2439     5. Reorganized pcre_ucp_findchar().
2442    Version 6.3 15-Aug-05
2443    ---------------------
2445     1. The file libpcre.pc.in did not have general read permission in the tarball.
2447     2. There were some problems when building without C++ support:
2449        (a) If C++ support was not built, "make install" and "make test" still
2450            tried to test it.
2452        (b) There were problems when the value of CXX was explicitly set. Some
2453            changes have been made to try to fix these, and ...
2455        (c) --disable-cpp can now be used to explicitly disable C++ support.
2457        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2458            backslash in a target when C++ was disabled. This confuses some
2459            versions of "make", apparently. Using an intermediate variable solves
2460            this. (Same for CPP_LOBJ.)
2462     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2463        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2464        necessary on certain architectures.
2466     4. Added a setting of -export-symbols-regex to the link command to remove
2467        those symbols that are exported in the C sense, but actually are local
2468        within the library, and not documented. Their names all begin with
2469        "_pcre_". This is not a perfect job, because (a) we have to except some
2470        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2471        available (and never for static libraries). I have made a note to try to
2472        find a way round (a) in the future.
2475  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
2476  ---------------------  ---------------------

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