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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.
79    Version 8.12 15-Jan-2011
80    ------------------------
82    1.  Fixed some typos in the markup of the man pages, and wrote a script that
83        checks for such things as part of the documentation building process.
85    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
86        --match-limit and --recursion-limit options (added for 8.11). In
87        particular, this made one of the standard tests fail. (The integer value
88        went into the wrong half of a long int.)
90    3.  If the --colour option was given to pcregrep with -v (invert match), it
91        did strange things, either producing crazy output, or crashing. It should,
92        of course, ignore a request for colour when reporting lines that do not
93        match.
95    4.  Another pcregrep bug caused similar problems if --colour was specified with
96        -M (multiline) and the pattern match finished with a line ending.
98    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
99        matched in multiline mode, the following line was shown as part of the
100        match. This seems wrong, so I have changed it.
102    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
103        the check for further matches in the same line (so they could be coloured)
104        to overrun the end of the current line. If another match was found, it was
105        incorrectly shown (and then shown again when found in the next line).
107    7.  If pcregrep was compiled under Windows, there was a reference to the
108        function pcregrep_exit() before it was defined. I am assuming this was
109        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
110        reported by a user. I've moved the definition above the reference.
113    Version 8.11 10-Dec-2010
114    ------------------------
116    1.  (*THEN) was not working properly if there were untried alternatives prior
117        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
118        backtracked to try for "b" instead of moving to the next alternative branch
119        at the same level (in this case, to look for "c"). The Perl documentation
120        is clear that when (*THEN) is backtracked onto, it goes to the "next
121        alternative in the innermost enclosing group".
123    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
124        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
125        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
126        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
127        (*THEN).
129    3.  If \s appeared in a character class, it removed the VT character from
130        the class, even if it had been included by some previous item, for example
131        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
132        of \s, but is part of the POSIX "space" class.)
134    4.  A partial match never returns an empty string (because you can always
135        match an empty string at the end of the subject); however the checking for
136        an empty string was starting at the "start of match" point. This has been
137        changed to the "earliest inspected character" point, because the returned
138        data for a partial match starts at this character. This means that, for
139        example, /(?<=abc)def/ gives a partial match for the subject "abc"
140        (previously it gave "no match").
142    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
143        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
144        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
145        has an implication that the given string is incomplete (because a partial
146        match is preferred over a full match). For this reason, these items now
147        give a partial match in this situation. [Aside: previously, the one case
148        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
149        match rather than a full match, which was wrong by the old rules, but is
150        now correct.]
152    6.  There was a bug in the handling of #-introduced comments, recognized when
153        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
154        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
155        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
156        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
157        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
158        places in pcre_compile().
160    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
161        comments when looking ahead for named forward references to subpatterns,
162        the only newline sequence it recognized was NL. It now handles newlines
163        according to the set newline convention.
165    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
166        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
167        cater for a lack of strerror(). These oversights have been fixed.
169    9.  Added --match-limit and --recursion-limit to pcregrep.
171    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
173    11. When the -o option was used, pcregrep was setting a return code of 1, even
174        when matches were found, and --line-buffered was not being honoured.
176    12. Added an optional parentheses number to the -o and --only-matching options
177        of pcregrep.
179    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
180        can match an empty string. The code to do it in pcretest and pcredemo
181        needed fixing:
183        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
184            only one byte after an empty string match just before CRLF (this case
185            just got forgotten; "any" and "anycrlf" were OK).
187        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
188            mode when an empty string match preceded an ASCII character followed by
189            a non-ASCII character. (The code for advancing by one character rather
190            than one byte was nonsense.)
192        (c) The pcredemo.c sample program did not have any code at all to handle
193            the cases when CRLF is a valid newline sequence.
195    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
196        as a starting offset was within the subject string. There is now a new
197        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
198        negative or greater than the length of the string. In order to test this,
199        pcretest is extended to allow the setting of negative starting offsets.
201    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
202        starting offset points to the beginning of a UTF-8 character was
203        unnecessarily clumsy. I tidied it up.
205    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
206        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
208    17. Nobody had reported that the --include_dir option, which was added in
209        release 7.7 should have been called --include-dir (hyphen, not underscore)
210        for compatibility with GNU grep. I have changed it to --include-dir, but
211        left --include_dir as an undocumented synonym, and the same for
212        --exclude-dir, though that is not available in GNU grep, at least as of
213        release 2.5.4.
215    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
216        characters from a string of bytes) have been redefined so as not to use
217        loops, in order to improve performance in some environments. At the same
218        time, I abstracted some of the common code into auxiliary macros to save
219        repetition (this should not affect the compiled code).
221    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
222        compile-time error is now given if \c is not followed by an ASCII
223        character, that is, a byte less than 128. (In EBCDIC mode, the code is
224        different, and any byte value is allowed.)
226    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
227        START_OPTIMIZE option, which is now allowed at compile time - but just
228        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
229        to pcregrep and other applications that have no direct access to PCRE
230        options. The new /Y option in pcretest sets this option when calling
231        pcre_compile().
233    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
234        back references. Groups containing recursive back references were forced to
235        be atomic by that change, but in the case of named groups, the amount of
236        memory required was incorrectly computed, leading to "Failed: internal
237        error: code overflow". This has been fixed.
239    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
240        pcretest.c, to avoid build problems in some Borland environments.
243    Version 8.10 25-Jun-2010
244    ------------------------
246    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
247        THEN.
249    2.  (*ACCEPT) was not working when inside an atomic group.
251    3.  Inside a character class, \B is treated as a literal by default, but
252        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
253        causes the error). The code is unchanged, but I tidied the documentation.
255    4.  Inside a character class, PCRE always treated \R and \X as literals,
256        whereas Perl faults them if its -w option is set. I have changed PCRE so
257        that it faults them when PCRE_EXTRA is set.
259    5.  Added support for \N, which always matches any character other than
260        newline. (It is the same as "." when PCRE_DOTALL is not set.)
262    6.  When compiling pcregrep with newer versions of gcc which may have
263        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
264        declared with attribute warn_unused_result" were given. Just casting the
265        result to (void) does not stop the warnings; a more elaborate fudge is
266        needed. I've used a macro to implement this.
268    7.  Minor change to pcretest.c to avoid a compiler warning.
270    8.  Added four artifical Unicode properties to help with an option to make
271        \s etc use properties (see next item). The new properties are: Xan
272        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
274    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
275        use Unicode properties. (*UCP) at the start of a pattern can be used to set
276        this option. Modified pcretest to add /W to test this facility. Added
277        REG_UCP to make it available via the POSIX interface.
279    10. Added --line-buffered to pcregrep.
281    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
282        studied, and the match started with a letter with a code point greater than
283        127 whose first byte was different to the first byte of the other case of
284        the letter, the other case of this starting letter was not recognized
285        (#976).
287    12. If a pattern that was studied started with a repeated Unicode property
288        test, for example, \p{Nd}+, there was the theoretical possibility of
289        setting up an incorrect bitmap of starting bytes, but fortunately it could
290        not have actually happened in practice until change 8 above was made (it
291        added property types that matched character-matching opcodes).
293    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
294        possible starting bytes for non-anchored patterns.
296    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
297        \R, and also a number of cases that involve Unicode properties, both
298        explicit and implicit when PCRE_UCP is set.
300    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
301        input, it could crash or give wrong results if characters with values
302        greater than 0xc0 were present in the subject string. (Detail: it assumed
303        UTF-8 input when processing these items.)
305    16. Added a lot of (int) casts to avoid compiler warnings in systems where
306        size_t is 64-bit (#991).
308    17. Added a check for running out of memory when PCRE is compiled with
309        --disable-stack-for-recursion (#990).
311    18. If the last data line in a file for pcretest does not have a newline on
312        the end, a newline was missing in the output.
314    19. The default pcre_chartables.c file recognizes only ASCII characters (values
315        less than 128) in its various bitmaps. However, there is a facility for
316        generating tables according to the current locale when PCRE is compiled. It
317        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
318        characters, are recognized by isspace() and therefore were getting set in
319        these tables, and indeed these tables seem to approximate to ISO 8859. This
320        caused a problem in UTF-8 mode when pcre_study() was used to create a list
321        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
322        which of course cannot start UTF-8 characters. I have changed the code so
323        that only real ASCII characters (less than 128) and the correct starting
324        bytes for UTF-8 encodings are set for characters greater than 127 when in
325        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
326        altogether.)
328    20. Added the /T option to pcretest so as to be able to run tests with non-
329        standard character tables, thus making it possible to include the tests
330        used for 19 above in the standard set of tests.
332    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
333        reference to a subpattern the other side of a comment that contains an
334        opening parenthesis caused either an internal compiling error, or a
335        reference to the wrong subpattern.
338    Version 8.02 19-Mar-2010
339    ------------------------
341    1.  The Unicode data tables have been updated to Unicode 5.2.0.
343    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
344        configured.
346    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
347        original author of that file, following a query about its status.
349    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
350        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
352    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
353        quantifier applied to a forward-referencing subroutine call, could compile
354        incorrect code or give the error "internal error: previously-checked
355        referenced subpattern not found".
357    6.  Both MS Visual Studio and Symbian OS have problems with initializing
358        variables to point to external functions. For these systems, therefore,
359        pcre_malloc etc. are now initialized to local functions that call the
360        relevant global functions.
362    7.  There were two entries missing in the vectors called coptable and poptable
363        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
364        I've fixed the data, and added a kludgy way of testing at compile time that
365        the lengths are correct (equal to the number of opcodes).
367    8.  Following on from 7, I added a similar kludge to check the length of the
368        eint vector in pcreposix.c.
370    9.  Error texts for pcre_compile() are held as one long string to avoid too
371        much relocation at load time. To find a text, the string is searched,
372        counting zeros. There was no check for running off the end of the string,
373        which could happen if a new error number was added without updating the
374        string.
376    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
378    11. \K was not working if it appeared in an atomic group or in a group that
379        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
380        \K is "not well defined" if used in an assertion. PCRE now accepts it if
381        the assertion is positive, but not if it is negative.
383    12. Change 11 fortuitously reduced the size of the stack frame used in the
384        "match()" function of pcre_exec.c by one pointer. Forthcoming
385        implementation of support for (*MARK) will need an extra pointer on the
386        stack; I have reserved it now, so that the stack frame size does not
387        decrease.
389    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
390        item in branch that calls a recursion is a subroutine call - as in the
391        second branch in the above example - was incorrectly given the compile-
392        time error "recursive call could loop indefinitely" because pcre_compile()
393        was not correctly checking the subroutine for matching a non-empty string.
395    14. The checks for overrunning compiling workspace could trigger after an
396        overrun had occurred. This is a "should never occur" error, but it can be
397        triggered by pathological patterns such as hundreds of nested parentheses.
398        The checks now trigger 100 bytes before the end of the workspace.
400    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
403    Version 8.01 19-Jan-2010
404    ------------------------
406    1.  If a pattern contained a conditional subpattern with only one branch (in
407        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
408        computed the wrong minimum data length (which is of course zero for such
409        subpatterns). This could cause incorrect "no match" results.
411    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
412        the pattern is reset in the first branch, pcre_compile() failed with
413        "internal error: code overflow at offset...". This happened only when
414        the reset was to the original external option setting. (An optimization
415        abstracts leading options settings into an external setting, which was the
416        cause of this.)
418    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
419        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
420        assertion pattern did not match (meaning that the assertion was true), it
421        was incorrectly treated as false if the SKIP had been reached during the
422        matching. This also applied to assertions used as conditions.
424    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
425        assertion subpattern, including such a pattern used as a condition,
426        unpredictable results occurred, instead of the error return
429    5.  The C++ GlobalReplace function was not working like Perl for the special
430        situation when an empty string is matched. It now does the fancy magic
431        stuff that is necessary.
433    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
434        removed. (These were left over from very, very early versions of PCRE.)
436    7.  Some cosmetic changes to the code to make life easier when compiling it
437        as part of something else:
439        (a) Change DEBUG to PCRE_DEBUG.
441        (b) In pcre_compile(), rename the member of the "branch_chain" structure
442            called "current" as "current_branch", to prevent a collision with the
443            Linux macro when compiled as a kernel module.
445        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
446            prevent a collision with the Linux macro when compiled as a kernel
447            module.
449    8.  In pcre_compile() there are some checks for integer overflows that used to
450        cast potentially large values to (double). This has been changed to that
451        when building, a check for int64_t is made, and if it is found, it is used
452        instead, thus avoiding the use of floating point arithmetic. (There is no
453        other use of FP in PCRE.) If int64_t is not found, the fallback is to
454        double.
456    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
457        2005 (difference between two addresses compared to an unsigned value).
459    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
460        custom one, because of the following reported problem in Windows:
462          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
463              under Win32.
464          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
465              therefore missing the function definition.
466          - The compiler thus generates a "C" signature for the test function.
467          - The linker fails to find the "C" function.
468          - PCRE fails to configure if asked to do so against libbz2.
470    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
471        messages were output:
473          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
474          rerunning libtoolize, to keep the correct libtool macros in-tree.
475          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
477        I have done both of these things.
479    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
480        most of the time, it *can* run out if it is given a pattern that contains a
481        runaway infinite recursion. I updated the discussion in the pcrestack man
482        page.
484    13. Now that we have gone to the x.xx style of version numbers, the minor
485        version may start with zero. Using 08 or 09 is a bad idea because users
486        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
487        interpreted as invalid octal numbers. I've updated the previous comment in
488        configure.ac, and also added a check that gives an error if 08 or 09 are
489        used.
491    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
492        causing partial matching to fail when the end of the subject matched \W
493        in a UTF-8 pattern where \W was quantified with a minimum of 3.
495    15. There were some discrepancies between the declarations in pcre_internal.h
496        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
497        their definitions. The declarations used "const uschar *" and the
498        definitions used USPTR. Even though USPTR is normally defined as "const
499        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
500        reported that: "This difference in casting confuses some C++ compilers, for
501        example, SunCC recognizes above declarations as different functions and
502        generates broken code for hbpcre." I have changed the declarations to use
503        USPTR.
505    16. GNU libtool is named differently on some systems. The autogen.sh script now
506        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
507        (FreeBSD).
509    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
510        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
511        comment: "Figure out how to create a longlong from a string: strtoll and
512        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
513        instance, but it only takes 2 args instead of 3!"
515    18. A subtle bug concerned with back references has been fixed by a change of
516        specification, with a corresponding code fix. A pattern such as
517        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
518        refers, was giving matches when it shouldn't. For example, xa=xaaa would
519        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
520        same bug. Such groups have to be quantified to be useful, or contained
521        inside another quantified group. (If there's no repetition, the reference
522        can never match.) The problem arises because, having left the group and
523        moved on to the rest of the pattern, a later failure that backtracks into
524        the group uses the captured value from the final iteration of the group
525        rather than the correct earlier one. I have fixed this in PCRE by forcing
526        any group that contains a reference to itself to be an atomic group; that
527        is, there cannot be any backtracking into it once it has completed. This is
528        similar to recursive and subroutine calls.
531    Version 8.00 19-Oct-09
532    ----------------------
534    1.  The table for translating pcre_compile() error codes into POSIX error codes
535        was out-of-date, and there was no check on the pcre_compile() error code
536        being within the table. This could lead to an OK return being given in
537        error.
539    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
540        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
541        in a Windows environment.
543    3.  The pcregrep --count option prints the count for each file even when it is
544        zero, as does GNU grep. However, pcregrep was also printing all files when
545        --files-with-matches was added. Now, when both options are given, it prints
546        counts only for those files that have at least one match. (GNU grep just
547        prints the file name in this circumstance, but including the count seems
548        more useful - otherwise, why use --count?) Also ensured that the
549        combination -clh just lists non-zero counts, with no names.
551    4.  The long form of the pcregrep -F option was incorrectly implemented as
552        --fixed_strings instead of --fixed-strings. This is an incompatible change,
553        but it seems right to fix it, and I didn't think it was worth preserving
554        the old behaviour.
556    5.  The command line items --regex=pattern and --regexp=pattern were not
557        recognized by pcregrep, which required --regex pattern or --regexp pattern
558        (with a space rather than an '='). The man page documented the '=' forms,
559        which are compatible with GNU grep; these now work.
561    6.  No libpcreposix.pc file was created for pkg-config; there was just
562        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
564    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
565        when UCP support is not needed, by modifying the Python script that
566        generates it from Unicode data files. This should not matter if the module
567        is correctly used as a library, but I received one complaint about 50K of
568        unwanted data. My guess is that the person linked everything into his
569        program rather than using a library. Anyway, it does no harm.
571    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
572        was a minimum greater than 1 for a wide character in a possessive
573        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
574        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
575        character. Chaos in the form of incorrect output or a compiling loop could
576        result.
578    9.  The restrictions on what a pattern can contain when partial matching is
579        requested for pcre_exec() have been removed. All patterns can now be
580        partially matched by this function. In addition, if there are at least two
581        slots in the offset vector, the offset of the earliest inspected character
582        for the match and the offset of the end of the subject are set in them when
583        PCRE_ERROR_PARTIAL is returned.
585    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
586        synonymous with PCRE_PARTIAL, for backwards compatibility, and
587        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
588        and may be more useful for multi-segment matching.
590    11. Partial matching with pcre_exec() is now more intuitive. A partial match
591        used to be given if ever the end of the subject was reached; now it is
592        given only if matching could not proceed because another character was
593        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
594        string "Z", which now yields "no match" instead of "partial match". In the
595        case of pcre_dfa_exec(), "no match" is given if every matching path for the
596        final character ended with (*FAIL).
598    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
599        if the pattern had a "must contain" character that was already found in the
600        earlier partial match, unless partial matching was again requested. For
601        example, with the pattern /dog.(body)?/, the "must contain" character is
602        "g". If the first part-match was for the string "dog", restarting with
603        "sbody" failed. This bug has been fixed.
605    13. The string returned by pcre_dfa_exec() after a partial match has been
606        changed so that it starts at the first inspected character rather than the
607        first character of the match. This makes a difference only if the pattern
608        starts with a lookbehind assertion or \b or \B (\K is not supported by
609        pcre_dfa_exec()). It's an incompatible change, but it makes the two
610        matching functions compatible, and I think it's the right thing to do.
612    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
613        so that the demonstration program is easily available in environments where
614        PCRE has not been installed from source.
616    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
617        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
618        library.
620    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
621        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
622        is not the first non-POSIX option to be added. Clearly some people find
623        these options useful.
625    17. If a caller to the POSIX matching function regexec() passes a non-zero
626        value for nmatch with a NULL value for pmatch, the value of
627        nmatch is forced to zero.
629    18. RunGrepTest did not have a test for the availability of the -u option of
630        the diff command, as RunTest does. It now checks in the same way as
631        RunTest, and also checks for the -b option.
633    19. If an odd number of negated classes containing just a single character
634        interposed, within parentheses, between a forward reference to a named
635        subpattern and the definition of the subpattern, compilation crashed with
636        an internal error, complaining that it could not find the referenced
637        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
638        [The bug was that it was starting one character too far in when skipping
639        over the character class, thus treating the ] as data rather than
640        terminating the class. This meant it could skip too much.]
642    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
643        /g option in pcretest when the pattern contains \K, which makes it possible
644        to have an empty string match not at the start, even when the pattern is
645        anchored. Updated pcretest and pcredemo to use this option.
647    21. If the maximum number of capturing subpatterns in a recursion was greater
648        than the maximum at the outer level, the higher number was returned, but
649        with unset values at the outer level. The correct (outer level) value is
650        now given.
652    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
653        PCRE did not set those parentheses (unlike Perl). I have now found a way to
654        make it do so. The string so far is captured, making this feature
655        compatible with Perl.
657    23. The tests have been re-organized, adding tests 11 and 12, to make it
658        possible to check the Perl 5.10 features against Perl 5.10.
660    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
661        pattern matches a fixed length string. PCRE did not allow this; now it
662        does. Neither allows recursion.
664    25. I finally figured out how to implement a request to provide the minimum
665        length of subject string that was needed in order to match a given pattern.
666        (It was back references and recursion that I had previously got hung up
667        on.) This code has now been added to pcre_study(); it finds a lower bound
668        to the length of subject needed. It is not necessarily the greatest lower
669        bound, but using it to avoid searching strings that are too short does give
670        some useful speed-ups. The value is available to calling programs via
671        pcre_fullinfo().
673    26. While implementing 25, I discovered to my embarrassment that pcretest had
674        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
675        study optimizations had never been tested with that matching function.
676        Oops. What is worse, even when it was passed study data, there was a bug in
677        pcre_dfa_exec() that meant it never actually used it. Double oops. There
678        were also very few tests of studied patterns with pcre_dfa_exec().
680    27. If (?| is used to create subpatterns with duplicate numbers, they are now
681        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
682        on the other side of the coin, they are no longer allowed to have different
683        names, because these cannot be distinguished in PCRE, and this has caused
684        confusion. (This is a difference from Perl.)
686    28. When duplicate subpattern names are present (necessarily with different
687        numbers, as required by 27 above), and a test is made by name in a
688        conditional pattern, either for a subpattern having been matched, or for
689        recursion in such a pattern, all the associated numbered subpatterns are
690        tested, and the overall condition is true if the condition is true for any
691        one of them. This is the way Perl works, and is also more like the way
692        testing by number works.
695    Version 7.9 11-Apr-09
696    ---------------------
698    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
699        (pcretest), all targets were linked against these libraries. This included
700        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
701        libraries. This caused unwanted dependencies to be created. This problem
702        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
703        pcretest is linked with readline.
705    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
706        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
707        moved outside it again, because FALSE and TRUE are already defined in AIX,
708        but BOOL is not.
710    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
711        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
713    4.  The pcregrep documentation said spaces were inserted as well as colons (or
714        hyphens) following file names and line numbers when outputting matching
715        lines. This is not true; no spaces are inserted. I have also clarified the
716        wording for the --colour (or --color) option.
718    5.  In pcregrep, when --colour was used with -o, the list of matching strings
719        was not coloured; this is different to GNU grep, so I have changed it to be
720        the same.
722    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
723        each matching line was coloured. Now it goes on to look for further matches
724        of any of the test patterns, which is the same behaviour as GNU grep.
726    7.  A pattern that could match an empty string could cause pcregrep to loop; it
727        doesn't make sense to accept an empty string match in pcregrep, so I have
728        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
729        seems to be how GNU grep behaves.
731    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
732        start or after a newline", because the conditional assertion was not being
733        correctly handled. The rule now is that both the assertion and what follows
734        in the first alternative must satisfy the test.
736    9.  If auto-callout was enabled in a pattern with a conditional group whose
737        condition was an assertion, PCRE could crash during matching, both with
738        pcre_exec() and pcre_dfa_exec().
740    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
741        used for matching.
743    11. Unicode property support in character classes was not working for
744        characters (bytes) greater than 127 when not in UTF-8 mode.
746    12. Added the -M command line option to pcretest.
748    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
750    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
752    16. Added comments and documentation about mis-use of no_arg in the C++
753        wrapper.
755    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
756        from Martin Jerabek that uses macro names for all relevant character and
757        string constants.
759    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
760        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
761        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
762        these, but not everybody uses configure.
764    19. A conditional group that had only one branch was not being correctly
765        recognized as an item that could match an empty string. This meant that an
766        enclosing group might also not be so recognized, causing infinite looping
767        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
768        with the subject "ab", where knowledge that the repeated group can match
769        nothing is needed in order to break the loop.
771    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
772        exec(), but without supplying a callout function, matching went wrong.
774    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
775        leak if the size of the offset vector was greater than 30. When the vector
776        is smaller, the saved offsets during recursion go onto a local stack
777        vector, but for larger vectors malloc() is used. It was failing to free
778        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
779        error, in fact).
781    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
782        heapframe that is used only when UTF-8 support is enabled. This caused no
783        problem, but was untidy.
785    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
786        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
787        included within another project.
789    24. Steven Van Ingelgem's patches to add more options to the CMake support,
790        slightly modified by me:
792          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
793              not building pcregrep.
795          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
796              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
798    25. Forward references, both numeric and by name, in patterns that made use of
799        duplicate group numbers, could behave incorrectly or give incorrect errors,
800        because when scanning forward to find the reference group, PCRE was not
801        taking into account the duplicate group numbers. A pattern such as
802        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
804    26. Changed a few more instances of "const unsigned char *" to USPTR, making
805        the feature of a custom pointer more persuasive (as requested by a user).
807    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
808        pcretest.c, inside #ifndefs, because it seems they are sometimes already
809        pre-defined.
811    28. Added support for (*UTF8) at the start of a pattern.
813    29. Arrange for flags added by the "release type" setting in CMake to be shown
814        in the configuration summary.
817    Version 7.8 05-Sep-08
818    ---------------------
820    1.  Replaced UCP searching code with optimized version as implemented for Ad
821        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
822        stage table and inline lookup instead of a function, giving speed ups of 2
823        to 5 times on some simple patterns that I tested. Permission was given to
824        distribute the MultiStage2.py script that generates the tables (it's not in
825        the tarball, but is in the Subversion repository).
827    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
828        scripts.
830    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
831        a group with a zero qualifier. The result of the study could be incorrect,
832        or the function might crash, depending on the pattern.
834    4.  Caseless matching was not working for non-ASCII characters in back
835        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
836        It now works when Unicode Property Support is available.
838    5.  In pcretest, an escape such as \x{de} in the data was always generating
839        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
840        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
841        truncation.
843    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
845    7.  Added two (int) casts to pcregrep when printing the difference of two
846        pointers, in case they are 64-bit values.
848    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
849        test 2 if it fails.
851    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
852        and a #define of that name to empty if it is not externally set. This is to
853        allow users of MSVC to set it if necessary.
855    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
856        the convenience functions in the pcre_get.c source file.
858    11. An option change at the start of a pattern that had top-level alternatives
859        could cause overwriting and/or a crash. This command provoked a crash in
860        some environments:
862          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
864        This potential security problem was recorded as CVE-2008-2371.
866    12. For a pattern where the match had to start at the beginning or immediately
867        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
868        pcre_dfa_exec() could read past the end of the passed subject if there was
869        no match. To help with detecting such bugs (e.g. with valgrind), I modified
870        pcretest so that it places the subject at the end of its malloc-ed buffer.
872    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
873        exec() might read past the end of the data buffer in UTF-8 mode.
875    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
876        the data contained the byte 0x85 as part of a UTF-8 character within its
877        first line. This applied both to normal and DFA matching.
879    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
880        /^[^d]*?$/8 failed to match "abc".
882    16. Added a missing copyright notice to pcrecpp_internal.h.
884    17. Make it more clear in the documentation that values returned from
885        pcre_exec() in ovector are byte offsets, not character counts.
887    18. Tidied a few places to stop certain compilers from issuing warnings.
889    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
890        supplied by Stefan Weber. I made a further small update for 7.8 because
891        there is a change of source arrangements: the pcre_searchfuncs.c module is
892        replaced by pcre_ucd.c.
895    Version 7.7 07-May-08
896    ---------------------
898    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
899        a string to a long long, pretend we don't even have a long long." This is
900        done by checking for the strtoq, strtoll, and _strtoi64 functions.
902    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
903        pre-7.6 versions, which defined a global no_arg variable instead of putting
904        it in the RE class. (See also #8 below.)
906    3.  Remove a line of dead code, identified by coverity and reported by Nuno
907        Lopes.
909    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
911        (1) The include/exclude patterns were being applied to the whole pathnames
912            of files, instead of just to the final components.
914        (2) If there was more than one level of directory, the subdirectories were
915            skipped unless they satisfied the include/exclude conditions. This is
916            inconsistent with GNU grep (and could even be seen as contrary to the
917            pcregrep specification - which I improved to make it absolutely clear).
918            The action now is always to scan all levels of directory, and just
919            apply the include/exclude patterns to regular files.
921    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
922        --exclude_dir in the tests to avoid scanning .svn directories.
924    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
925        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
926        doesn't support NULs in patterns.
928    7.  Added some missing "const"s to declarations of static tables in
929        pcre_compile.c and pcre_dfa_exec.c.
931    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
932        caused by fix #2  above. (Subsequently also a second patch to fix the
933        first patch. And a third patch - this was a messy problem.)
935    9.  Applied Craig's patch to remove the use of push_back().
937    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
938        matching function regexec().
940    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
941        which, however, unlike Perl's \g{...}, are subroutine calls, not back
942        references. PCRE supports relative numbers with this syntax (I don't think
943        Oniguruma does).
945    12. Previously, a group with a zero repeat such as (...){0} was completely
946        omitted from the compiled regex. However, this means that if the group
947        was called as a subroutine from elsewhere in the pattern, things went wrong
948        (an internal error was given). Such groups are now left in the compiled
949        pattern, with a new opcode that causes them to be skipped at execution
950        time.
952    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
953        to the way PCRE behaves:
955        (a) A lone ] character is dis-allowed (Perl treats it as data).
957        (b) A back reference to an unmatched subpattern matches an empty string
958            (Perl fails the current match path).
960        (c) A data ] in a character class must be notated as \] because if the
961            first data character in a class is ], it defines an empty class. (In
962            Perl it is not possible to have an empty class.) The empty class []
963            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
964            The negative empty class [^] matches any one character, independently
965            of the DOTALL setting.
967    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
968        non-existent subpattern following a character class starting with ']' and
969        containing () gave an internal compiling error instead of "reference to
970        non-existent subpattern". Fortunately, when the pattern did exist, the
971        compiled code was correct. (When scanning forwards to check for the
972        existencd of the subpattern, it was treating the data ']' as terminating
973        the class, so got the count wrong. When actually compiling, the reference
974        was subsequently set up correctly.)
976    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
977        it was being rejected as not supported by pcre_dfa_exec(), even though
978        other assertions are supported. I have made pcre_dfa_exec() support
979        (*FAIL).
981    16. The implementation of 13c above involved the invention of a new opcode,
982        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
983        cannot be changed at match time, I realized I could make a small
984        improvement to matching performance by compiling OP_ALLANY instead of
985        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
986        on the OP_ANY path.
988    17. Compiling pcretest on Windows with readline support failed without the
989        following two fixes: (1) Make the unistd.h include conditional on
990        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
992    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
993        ncurses library to be included for pcretest when ReadLine support is
994        requested, but also to allow for it to be overridden. This patch came from
995        Daniel Bergström.
997    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
998        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
999        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1000        spotting this.
1003    Version 7.6 28-Jan-08
1004    ---------------------
1006    1.  A character class containing a very large number of characters with
1007        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1008        overflow.
1010    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1011        HAVE_LONG_LONG is not defined.
1013    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1014        bring them up to date and include new features. This patch includes:
1016        - Fixed PH's badly added libz and libbz2 support.
1017        - Fixed a problem with static linking.
1018        - Added pcredemo. [But later removed - see 7 below.]
1019        - Fixed dftables problem and added an option.
1020        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1021            HAVE_LONG_LONG.
1022        - Added readline support for pcretest.
1023        - Added an listing of the option settings after cmake has run.
1025    4.  A user submitted a patch to Makefile that makes it easy to create
1026        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1027        Makefile.am that cause it to include this special target, without
1028        affecting anything else. Note that the same mingw target plus all
1029        the other distribution libraries and programs are now supported
1030        when configuring with CMake (see 6 below) instead of with
1031        Configure/Make.
1033    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1034        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1035        exported in the Windows port". It has not yet been confirmed that the patch
1036        solves the problem, but it does no harm.
1038    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1039        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1040        with CMake, and also correct the comment about stack recursion.
1042    7.  Remove the automatic building of pcredemo from the ./configure system and
1043        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1044        of a program that users should build themselves after PCRE is installed, so
1045        building it automatically is not really right. What is more, it gave
1046        trouble in some build environments.
1048    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1051    Version 7.5 10-Jan-08
1052    ---------------------
1054    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1055        values in parens when parsing an RE using the C++ wrapper."
1057    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1058        Characters greater than 255 were excluded from the class instead of being
1059        included.
1061    3.  The same bug as (2) above applied to negated POSIX classes such as
1062        [:^space:].
1064    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1065        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1066        I have changed it.
1068    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1069        first named subpattern) and a construct such as (?&a) would reference the
1070        first named subpattern whose name started with "a" (in other words, the
1071        length check was missing). Both these problems are fixed. "Subpattern name
1072        expected" is now given for (?&) (a zero-length name), and this patch also
1073        makes it give the same error for \k'' (previously it complained that that
1074        was a reference to a non-existent subpattern).
1076    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1077        this is right because (?- can be followed by option settings as well as by
1078        digits. I have, however, made the messages clearer.
1080    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1081        than the number used in the conditional) now cause a compile-time error.
1082        This is actually not compatible with Perl, which accepts such patterns, but
1083        treats the conditional as always being FALSE (as PCRE used to), but it
1084        seems to me that giving a diagnostic is better.
1086    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1087        and messages.
1089    9.  Fix two occurrences of "backslash" in comments that should have been
1090        "backspace".
1092    10. Remove two redundant lines of code that can never be obeyed (their function
1093        was moved elsewhere).
1095    11. The program that makes PCRE's Unicode character property table had a bug
1096        which caused it to generate incorrect table entries for sequences of
1097        characters that have the same character type, but are in different scripts.
1098        It amalgamated them into a single range, with the script of the first of
1099        them. In other words, some characters were in the wrong script. There were
1100        thirteen such cases, affecting characters in the following ranges:
1102          U+002b0 - U+002c1
1103          U+0060c - U+0060d
1104          U+0061e - U+00612
1105          U+0064b - U+0065e
1106          U+0074d - U+0076d
1107          U+01800 - U+01805
1108          U+01d00 - U+01d77
1109          U+01d9b - U+01dbf
1110          U+0200b - U+0200f
1111          U+030fc - U+030fe
1112          U+03260 - U+0327f
1113          U+0fb46 - U+0fbb1
1114          U+10450 - U+1049d
1116    12. The -o option (show only the matching part of a line) for pcregrep was not
1117        compatible with GNU grep in that, if there was more than one match in a
1118        line, it showed only the first of them. It now behaves in the same way as
1119        GNU grep.
1121    13. If the -o and -v options were combined for pcregrep, it printed a blank
1122        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1123        does the same. The return code can be used to tell if there were any
1124        non-matching lines.
1126    14. Added --file-offsets and --line-offsets to pcregrep.
1128    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1129        infinitely looping recursion. The bug was that positive lookaheads were not
1130        being skipped when checking for a possible empty match (negative lookaheads
1131        and both kinds of lookbehind were skipped).
1133    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1134        inclusion of <windows.h> to before rather than after the definition of
1135        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1137    17. Specifying a possessive quantifier with a specific limit for a Unicode
1138        character property caused pcre_compile() to compile bad code, which led at
1139        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1140        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1141        caused the error; without that there was no problem.
1143    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1145    19. Added --enable-pcretest-libreadline.
1147    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1148        RE::GlobalReplace(). As a result, the number of replacements returned was
1149        double what it should be. I removed one of the increments, but Craig sent a
1150        later patch that removed the other one (the right fix) and added unit tests
1151        that check the return values (which was not done before).
1153    21. Several CMake things:
1155        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1156            the names libpcre and libpcreposix, not just pcre and pcreposix.
1158        (2) The above change means that pcretest and pcregrep are now correctly
1159            linked with the newly-built libraries, not previously installed ones.
1163    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1164        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1165        UTF-8 newline character). The key issue is that the pattern starts .*;
1166        this means that the match must be either at the beginning, or after a
1167        newline. The bug was in the code for advancing after a failed match and
1168        checking that the new position followed a newline. It was not taking
1169        account of UTF-8 characters correctly.
1171    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1172        character classes. PCRE was not treating the sequence [:...:] as a
1173        character class unless the ... were all letters. Perl, however, seems to
1174        allow any characters between [: and :], though of course it rejects as
1175        unknown any "names" that contain non-letters, because all the known class
1176        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1177        for example, whereas PCRE did not - it did not recognize a POSIX character
1178        class. This seemed a bit dangerous, so the code has been changed to be
1179        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1180        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1181        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1182        Perl does, and where it didn't before.
1184    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1185        Windows environments %n is disabled by default.
1188    Version 7.4 21-Sep-07
1189    ---------------------
1191    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1192        means that a class such as [\s] counted as "explicit reference to CR or
1193        LF". That isn't really right - the whole point of the change was to try to
1194        help when there was an actual mention of one of the two characters. So now
1195        the change happens only if \r or \n (or a literal CR or LF) character is
1196        encountered.
1198    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1199        of both had grown to the point where there were only 3 bits left.
1200        Fortunately, there was spare space in the data structure, and so I have
1201        moved the internal flags into a new 16-bit field to free up more option
1202        bits.
1204    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1205        but did not set the internal JCHANGED flag - either of these is enough to
1206        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1207        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1208        start sets both bits.
1210    4.  Added options (at build time, compile time, exec time) to change \R from
1211        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1213    5.  doc/pcresyntax.html was missing from the distribution.
1215    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1216        compatibility, even though it is no longer used.
1218    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1219        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1220        windows.h file is present (where different names are used). [This was
1221        reversed later after testing - see 16 below.]
1223    8.  Changed all #include <config.h> to #include "config.h". There were also
1224        some further <pcre.h> cases that I changed to "pcre.h".
1226    9.  When pcregrep was used with the --colour option, it missed the line ending
1227        sequence off the lines that it output.
1229    10. It was pointed out to me that arrays of string pointers cause lots of
1230        relocations when a shared library is dynamically loaded. A technique of
1231        using a single long string with a table of offsets can drastically reduce
1232        these. I have refactored PCRE in four places to do this. The result is
1233        dramatic:
1235          Originally:                          290
1236          After changing UCP table:            187
1237          After changing error message table:   43
1238          After changing table of "verbs"       36
1239          After changing table of Posix names   22
1241        Thanks to the folks working on Gregex for glib for this insight.
1243    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1244        unicode-properties was also set.
1246    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1248    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1249        checked only for CRLF.
1251    14. Added casts to pcretest.c to avoid compiler warnings.
1253    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1255    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1256        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1257        entirely. This removes changes made in 7 above.
1259    17. The CMake files have been updated, and there is now more information about
1260        building with CMake in the NON-UNIX-USE document.
1263    Version 7.3 28-Aug-07
1264    ---------------------
1266     1. In the rejigging of the build system that eventually resulted in 7.1, the
1267        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1268        brackets there is not right, since it causes compilers to look for an
1269        installed pcre.h, not the version that is in the source that is being
1270        compiled (which of course may be different). I have changed it back to:
1272          #include "pcre.h"
1274        I have a vague recollection that the change was concerned with compiling in
1275        different directories, but in the new build system, that is taken care of
1276        by the VPATH setting the Makefile.
1278     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1279        when the subject happened to end in the byte 0x85 (e.g. if the last
1280        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1281        characters but of course it shouldn't be taken as a newline when it is part
1282        of another character. The bug was that, for an unlimited repeat of . in
1283        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1284        characters when looking for a newline.
1286     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1288     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1289        in debug output.
1291     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1292        long printing in the pcrecpp unittest when running under MinGW.
1294     6. ESC_K was left out of the EBCDIC table.
1296     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1297        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1298        limit also applies to "virtual nesting" when a pattern is recursive, and in
1299        this case 1000 isn't so big. I have been able to remove this limit at the
1300        expense of backing off one optimization in certain circumstances. Normally,
1301        when pcre_exec() would call its internal match() function recursively and
1302        immediately return the result unconditionally, it uses a "tail recursion"
1303        feature to save stack. However, when a subpattern that can match an empty
1304        string has an unlimited repetition quantifier, it no longer makes this
1305        optimization. That gives it a stack frame in which to save the data for
1306        checking that an empty string has been matched. Previously this was taken
1307        from the 1000-entry workspace that had been reserved. So now there is no
1308        explicit limit, but more stack is used.
1310     8. Applied Daniel's patches to solve problems with the import/export magic
1311        syntax that is required for Windows, and which was going wrong for the
1312        pcreposix and pcrecpp parts of the library. These were overlooked when this
1313        problem was solved for the main library.
1315     9. There were some crude static tests to avoid integer overflow when computing
1316        the size of patterns that contain repeated groups with explicit upper
1317        limits. As the maximum quantifier is 65535, the maximum group length was
1318        set at 30,000 so that the product of these two numbers did not overflow a
1319        32-bit integer. However, it turns out that people want to use groups that
1320        are longer than 30,000 bytes (though not repeat them that many times).
1321        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1322        made it possible to implement the integer overflow checks in a much more
1323        dynamic way, which I have now done. The artificial limitation on group
1324        length has been removed - we now have only the limit on the total length of
1325        the compiled pattern, which depends on the LINK_SIZE setting.
1327    10. Fixed a bug in the documentation for get/copy named substring when
1328        duplicate names are permitted. If none of the named substrings are set, the
1329        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1330        empty string.
1332    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1333        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1334        because the ] is interpreted as the first data character and the
1335        terminating ] is not found. PCRE has been made compatible with Perl in this
1336        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1337        cause memory overwriting.
1339    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1340        string has been matched (to stop an infinite loop). It was not recognizing
1341        a conditional subpattern that could match an empty string if that
1342        subpattern was within another subpattern. For example, it looped when
1343        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1344        condition was not nested. This bug has been fixed.
1346    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1347        past the start of the subject in the presence of bytes with the top bit
1348        set, for example "\x8aBCD".
1350    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1351        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1353    14. Optimized (?!) to (*FAIL).
1355    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1356        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1357        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1358        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1359        does: it's just the validity check that is more restrictive.
1361    16. Inserted checks for integer overflows during escape sequence (backslash)
1362        processing, and also fixed erroneous offset values for syntax errors during
1363        backslash processing.
1365    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1366        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1368    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1369        caused an overrun.
1371    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1372        something other than just ASCII characters) inside a group that had an
1373        unlimited repeat caused a loop at compile time (while checking to see
1374        whether the group could match an empty string).
1376    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1377        [\P{Any}] did so. (Error in the code for printing property names.)
1379    21. An orphan \E inside a character class could cause a crash.
1381    22. A repeated capturing bracket such as (A)? could cause a wild memory
1382        reference during compilation.
1384    23. There are several functions in pcre_compile() that scan along a compiled
1385        expression for various reasons (e.g. to see if it's fixed length for look
1386        behind). There were bugs in these functions when a repeated \p or \P was
1387        present in the pattern. These operators have additional parameters compared
1388        with \d, etc, and these were not being taken into account when moving along
1389        the compiled data. Specifically:
1391        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1392            length.
1394        (b) An item such as \pL+ within a repeated group could cause crashes or
1395            loops.
1397        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1398            "reference to non-existent subpattern" error.
1400        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1402    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1403        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1405    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1407    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1408        character were causing crashes (broken optimization).
1410    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1411        \p or \P) caused a compile-time loop.
1413    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1414        break. For example, the unstudied pattern [\r\n]A does not match the string
1415        "\r\nA" because change 7.0/46 below moves the current point on by two
1416        characters after failing to match at the start. However, the pattern \nA
1417        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1418        the same is true. There doesn't seem any very clean way out of this, but
1419        what I have chosen to do makes the common cases work: PCRE now takes note
1420        of whether there can be an explicit match for \r or \n anywhere in the
1421        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1422        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1423        pattern has explicit CR or LF references.
1425    29. Added (*CR) etc for changing newline setting at start of pattern.
1428    Version 7.2 19-Jun-07
1429    ---------------------
1431     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1432        which is apparently normally available under Windows.
1434     2. Re-jig the pcregrep tests with different newline settings in an attempt
1435        to make them independent of the local environment's newline setting.
1437     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1439     4. Some of the "internals" tests were previously cut out when the link size
1440        was not 2, because the output contained actual offsets. The recent new
1441        "Z" feature of pcretest means that these can be cut out, making the tests
1442        usable with all link sizes.
1444     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1445        stack recursion. This gives a massive performance boost under BSD, but just
1446        a small improvement under Linux. However, it saves one field in the frame
1447        in all cases.
1449     6. Added more features from the forthcoming Perl 5.10:
1451        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1452            recursion call. It refers to the nth most recently opened parentheses.
1454        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1455            to be opened parentheses.
1457        (c) Conditions that refer to capturing parentheses can be specified
1458            relatively, for example, (?(-2)... or (?(+3)...
1460        (d) \K resets the start of the current match so that everything before
1461            is not part of it.
1463        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1465        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1466            reference syntax.
1468        (g) (?| introduces a group in which the numbering of parentheses in each
1469            alternative starts with the same number.
1471        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1473     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1476     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1477        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1478        for detecting groups that can match an empty string.
1480     9. A pattern with a very large number of alternatives (more than several
1481        hundred) was running out of internal workspace during the pre-compile
1482        phase, where pcre_compile() figures out how much memory will be needed. A
1483        bit of new cunning has reduced the workspace needed for groups with
1484        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1485        workspace instead of running out of the 4096 that are available.
1487    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1489    11. Applied patch from Google to remove an optimization that didn't quite work.
1490        The report of the bug said:
1492          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1493          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1494          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1496    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1497        it matched the wrong number of bytes.
1500    Version 7.1 24-Apr-07
1501    ---------------------
1503     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1504        that is more "standard", making use of automake and other Autotools. There
1505        is some re-arrangement of the files and adjustment of comments consequent
1506        on this.
1508     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1509        for recursive directory scanning broke on some systems because the files
1510        are not scanned in any specific order and on different systems the order
1511        was different. A call to "sort" has been inserted into RunGrepTest for the
1512        approprate test as a short-term fix. In the longer term there may be an
1513        alternative.
1515     3. I had an email from Eric Raymond about problems translating some of PCRE's
1516        man pages to HTML (despite the fact that I distribute HTML pages, some
1517        people do their own conversions for various reasons). The problems
1518        concerned the use of low-level troff macros .br and .in. I have therefore
1519        removed all such uses from the man pages (some were redundant, some could
1520        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1521        HTML has been updated to handle .nf/.fi and to complain if it encounters
1522        .br or .in.
1524     4. Updated comments in configure.ac that get placed in config.h.in and also
1525        arranged for config.h to be included in the distribution, with the name
1526        config.h.generic, for the benefit of those who have to compile without
1527        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1529     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1530        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1531        makevp.bat for the current PCRE, using the additional files
1532        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1534     6. A Windows user reported a minor discrepancy with test 2, which turned out
1535        to be caused by a trailing space on an input line that had got lost in his
1536        copy. The trailing space was an accident, so I've just removed it.
1538     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1539        that is needed.
1541     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1542        as "const" (a) because they are and (b) because it helps the PHP
1543        maintainers who have recently made a script to detect big data structures
1544        in the php code that should be moved to the .rodata section. I remembered
1545        to update Builducptable as well, so it won't revert if ucptable.h is ever
1546        re-created.
1548     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1549        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1550        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1551        support is not required. This saves 1.5-2K of code, which is important in
1552        some applications.
1554        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1555        so as not to refer to the tables, even though these functions will never be
1556        called when UTF-8 support is disabled. Otherwise there are problems with a
1557        shared library.
1559    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1561        (a) It was defining its arguments as char * instead of void *.
1563        (b) It was assuming that all moves were upwards in memory; this was true
1564            a long time ago when I wrote it, but is no longer the case.
1566        The emulated memove() is provided for those environments that have neither
1567        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1568        is clearly not the case, as these two bugs were recently reported.
1570    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1571        and Detrail to create the HTML documentation, the .txt form of the man
1572        pages, and it removes trailing spaces from listed files. It also creates
1573        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1574        case, it wraps all the #defines with #ifndefs. This script should be run
1575        before "make dist".
1577    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1578        with Unicode property support.
1580        (a) For a maximizing quantifier, if the two different cases of the
1581            character were of different lengths in their UTF-8 codings (there are
1582            some cases like this - I found 11), and the matching function had to
1583            back up over a mixture of the two cases, it incorrectly assumed they
1584            were both the same length.
1586        (b) When PCRE was configured to use the heap rather than the stack for
1587            recursion during matching, it was not correctly preserving the data for
1588            the other case of a UTF-8 character when checking ahead for a match
1589            while processing a minimizing repeat. If the check also involved
1590            matching a wide character, but failed, corruption could cause an
1591            erroneous result when trying to check for a repeat of the original
1592            character.
1594    13. Some tidying changes to the testing mechanism:
1596        (a) The RunTest script now detects the internal link size and whether there
1597            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1598            values substituted by "configure". (The RunGrepTest script already did
1599            this for UTF-8.) The configure.ac script no longer substitutes the
1600            relevant variables.
1602        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1603            with length and offset values. This means that the output is different
1604            for different internal link sizes. Test 2 is skipped for link sizes
1605            other than 2 because of this, bypassing the problem. Unfortunately,
1606            there was also a test in test 3 (the locale tests) that used /B and
1607            failed for link sizes other than 2. Rather than cut the whole test out,
1608            I have added a new /Z option to pcretest that replaces the length and
1609            offset values with spaces. This is now used to make test 3 independent
1610            of link size. (Test 2 will be tidied up later.)
1612    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1613        segmentation fault instead of returning the appropriate error message.
1615    15. In multiline mode when the newline sequence was set to "any", the pattern
1616        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1617        This doesn't seem right; it now treats the CRLF combination as the line
1618        ending, and so does not match in that case. It's only a pattern such as ^$
1619        that would hit this one: something like ^ABC$ would have failed after \r
1620        and then tried again after \r\n.
1622    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1623        in an attempt to make files that differ only in their line terminators
1624        compare equal. This works on Linux.
1626    17. Under certain error circumstances pcregrep might try to free random memory
1627        as it exited. This is now fixed, thanks to valgrind.
1629    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1630        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1631        was because its rules for how to advance for /g after matching an empty
1632        string at the end of a line did not allow for this case. They now check for
1633        it specially.
1635    20. pcretest is supposed to handle patterns and data of any length, by
1636        extending its buffers when necessary. It was getting this wrong when the
1637        buffer for a data line had to be extended.
1639    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1640        CRLF as a newline sequence.
1642    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1643        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1644        I have nevertheless tidied it up.
1646    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1648    24. Added a man page for pcre-config.
1651    Version 7.0 19-Dec-06
1652    ---------------------
1654     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1655        moving to gcc 4.1.1.
1657     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1658        sys/time.h, which is documented as needed for this function. It doesn't
1659        seem to matter on Linux, but it showed up on some releases of OS X.
1661     3. It seems that there are systems where bytes whose values are greater than
1662        127 match isprint() in the "C" locale. The "C" locale should be the
1663        default when a C program starts up. In most systems, only ASCII printing
1664        characters match isprint(). This difference caused the output from pcretest
1665        to vary, making some of the tests fail. I have changed pcretest so that:
1667        (a) When it is outputting text in the compiled version of a pattern, bytes
1668            other than 32-126 are always shown as hex escapes.
1670        (b) When it is outputting text that is a matched part of a subject string,
1671            it does the same, unless a different locale has been set for the match
1672            (using the /L modifier). In this case, it uses isprint() to decide.
1674     4. Fixed a major bug that caused incorrect computation of the amount of memory
1675        required for a compiled pattern when options that changed within the
1676        pattern affected the logic of the preliminary scan that determines the
1677        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1678        that the computed length was too small. The symptoms of this bug were
1679        either the PCRE error "internal error: code overflow" from pcre_compile(),
1680        or a glibc crash with a message such as "pcretest: free(): invalid next
1681        size (fast)". Examples of patterns that provoked this bug (shown in
1682        pcretest format) are:
1684          /(?-x: )/x
1685          /(?x)(?-x: \s*#\s*)/
1686          /((?i)[\x{c0}])/8
1687          /(?i:[\x{c0}])/8
1689        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1690        is now done differently.
1692     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1693        wrapper classes; (b) implement a new function in the C++ scanner that is
1694        more efficient than the old way of doing things because it avoids levels of
1695        recursion in the regex matching; (c) add a paragraph to the documentation
1696        for the FullMatch() function.
1698     6. The escape sequence \n was being treated as whatever was defined as
1699        "newline". Not only was this contrary to the documentation, which states
1700        that \n is character 10 (hex 0A), but it also went horribly wrong when
1701        "newline" was defined as CRLF. This has been fixed.
1703     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1704        was being set to -1 for the "end of line" case (supposedly a value that no
1705        character can have). Though this value is never used (the check for end of
1706        line is "zero bytes in current character"), it caused compiler complaints.
1707        I've changed it to 0xffffffff.
1709     8. In pcre_version.c, the version string was being built by a sequence of
1710        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1711        string (as it is for production releases) called a macro with an empty
1712        argument. The C standard says the result of this is undefined. The gcc
1713        compiler treats it as an empty string (which was what was wanted) but it is
1714        reported that Visual C gives an error. The source has been hacked around to
1715        avoid this problem.
1717     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1718        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1719        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1720        of them did).
1722    10. Originally, pcretest opened its input and output without "b"; then I was
1723        told that "b" was needed in some environments, so it was added for release
1724        5.0 to both the input and output. (It makes no difference on Unix-like
1725        systems.) Later I was told that it is wrong for the input on Windows. I've
1726        now abstracted the modes into two macros, to make it easier to fiddle with
1727        them, and removed "b" from the input mode under Windows.
1729    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1731    12. Added -help and --help to pcretest as an official way of being reminded
1732        of the options.
1734    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1735        and pcrecpp.cc because they annoy compilers at high warning levels.
1737    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1739    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1740        scripts are not C programs :-) and which was not noticed because it works
1741        on Linux.
1743    16. pcretest is supposed to handle any length of pattern and data line (as one
1744        line or as a continued sequence of lines) by extending its input buffer if
1745        necessary. This feature was broken for very long pattern lines, leading to
1746        a string of junk being passed to pcre_compile() if the pattern was longer
1747        than about 50K.
1749    17. I have done a major re-factoring of the way pcre_compile() computes the
1750        amount of memory needed for a compiled pattern. Previously, there was code
1751        that made a preliminary scan of the pattern in order to do this. That was
1752        OK when PCRE was new, but as the facilities have expanded, it has become
1753        harder and harder to keep it in step with the real compile phase, and there
1754        have been a number of bugs (see for example, 4 above). I have now found a
1755        cunning way of running the real compile function in a "fake" mode that
1756        enables it to compute how much memory it would need, while actually only
1757        ever using a few hundred bytes of working memory and without too many
1758        tests of the mode. This should make future maintenance and development
1759        easier. A side effect of this work is that the limit of 200 on the nesting
1760        depth of parentheses has been removed (though this was never a serious
1761        limitation, I suspect). However, there is a downside: pcre_compile() now
1762        runs more slowly than before (30% or more, depending on the pattern). I
1763        hope this isn't a big issue. There is no effect on runtime performance.
1765    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1766        newline (only possible for the last line of a file) and it was a
1767        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1769    19. Added additional timing features to pcretest. (1) The -tm option now times
1770        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1771        separate command line item, by a number that specifies the number of
1772        repeats to use when timing. The default is 50000; this gives better
1773        precision, but takes uncomfortably long for very large patterns.
1775    20. Extended pcre_study() to be more clever in cases where a branch of a
1776        subpattern has no definite first character. For example, (a*|b*)[cd] would
1777        previously give no result from pcre_study(). Now it recognizes that the
1778        first character must be a, b, c, or d.
1780    21. There was an incorrect error "recursive call could loop indefinitely" if
1781        a subpattern (or the entire pattern) that was being tested for matching an
1782        empty string contained only one non-empty item after a nested subpattern.
1783        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1784        incorrectly, because the \d was being skipped in the check.
1786    22. The pcretest program now has a new pattern option /B and a command line
1787        option -b, which is equivalent to adding /B to every pattern. This causes
1788        it to show the compiled bytecode, without the additional information that
1789        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1790        is the same as /B/I).
1792    23. A new optimization is now able automatically to treat some sequences such
1793        as a*b as a*+b. More specifically, if something simple (such as a character
1794        or a simple class like \d) has an unlimited quantifier, and is followed by
1795        something that cannot possibly match the quantified thing, the quantifier
1796        is automatically "possessified".
1798    24. A recursive reference to a subpattern whose number was greater than 39
1799        went wrong under certain circumstances in UTF-8 mode. This bug could also
1800        have affected the operation of pcre_study().
1802    25. Realized that a little bit of performance could be had by replacing
1803        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1805    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1807    27. Possessive quantifiers such as a++ were previously implemented by turning
1808        them into atomic groups such as ($>a+). Now they have their own opcodes,
1809        which improves performance. This includes the automatically created ones
1810        from 23 above.
1812    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1813        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1814        the first matched character to be a colon. This applied both to named and
1815        numbered groups.
1817    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1819    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1820        building PCRE on Windows easier, so I have included it in the distribution.
1822    31. There is now a check in pcretest against a ridiculously large number being
1823        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1824        loop, the loop is abandoned.
1826    32. Forward references to subpatterns in conditions such as (?(2)...) where
1827        subpattern 2 is defined later cause pcre_compile() to search forwards in
1828        the pattern for the relevant set of parentheses. This search went wrong
1829        when there were unescaped parentheses in a character class, parentheses
1830        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1832    33. "Subroutine" calls and backreferences were previously restricted to
1833        referencing subpatterns earlier in the regex. This restriction has now
1834        been removed.
1836    34. Added a number of extra features that are going to be in Perl 5.10. On the
1837        whole, these are just syntactic alternatives for features that PCRE had
1838        previously implemented using the Python syntax or my own invention. The
1839        other formats are all retained for compatibility.
1841        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1842            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1843            also .NET compatible.
1845        (b) A recursion or subroutine call to a named group can now be defined as
1846            (?&name) as well as (?P>name).
1848        (c) A backreference to a named group can now be defined as \k<name> or
1849            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1850            5.10, are also .NET compatible.
1852        (d) A conditional reference to a named group can now use the syntax
1853            (?(<name>) or (?('name') as well as (?(name).
1855        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1856            groups (named and numbered) that are never evaluated inline, but can be
1857            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1858            is always false. There may be only one alternative in such a group.
1860        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1861            as the simple (?(R). The condition is true only if the most recent
1862            recursion is that of the given number or name. It does not search out
1863            through the entire recursion stack.
1865        (g) The escape \gN or \g{N} has been added, where N is a positive or
1866            negative number, specifying an absolute or relative reference.
1868    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1869        some "unreachable code" warnings.
1871    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1872        things, this adds five new scripts.
1874    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1875        There were also incompatibilities regarding the handling of \Q..\E inside
1876        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1877        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1879    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1880        matches an empty string, and forcibly breaks the loop. There were bugs in
1881        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1882        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1883        separate and independent bugs (that affected different cases) have been
1884        fixed.
1886    39. Refactored the code to abolish the use of different opcodes for small
1887        capturing bracket numbers. This is a tidy that I avoided doing when I
1888        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1889        The new approach is not only tidier, it makes it possible to reduce the
1890        memory needed to fix the previous bug (38).
1892    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1893        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1894        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1895        mode.
1897    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1898        report.
1900    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1901        copy construction and assignment in the C++ wrapper.
1903    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1904        couple of bugs that could have given wrong results in the "--newline=crlf"
1905        case.
1907    44. Added a number of casts and did some reorganization of signed/unsigned int
1908        variables following suggestions from Dair Grant. Also renamed the variable
1909        "this" as "item" because it is a C++ keyword.
1911    45. Arranged for dftables to add
1913          #include "pcre_internal.h"
1915        to pcre_chartables.c because without it, gcc 4.x may remove the array
1916        definition from the final binary if PCRE is built into a static library and
1917        dead code stripping is activated.
1919    46. For an unanchored pattern, if a match attempt fails at the start of a
1920        newline sequence, and the newline setting is CRLF or ANY, and the next two
1921        characters are CRLF, advance by two characters instead of one.
1924    Version 6.7 04-Jul-06
1925    ---------------------
1927     1. In order to handle tests when input lines are enormously long, pcretest has
1928        been re-factored so that it automatically extends its buffers when
1929        necessary. The code is crude, but this _is_ just a test program. The
1930        default size has been increased from 32K to 50K.
1932     2. The code in pcre_study() was using the value of the re argument before
1933        testing it for NULL. (Of course, in any sensible call of the function, it
1934        won't be NULL.)
1936     3. The memmove() emulation function in pcre_internal.h, which is used on
1937        systems that lack both memmove() and bcopy() - that is, hardly ever -
1938        was missing a "static" storage class specifier.
1940     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1941        containing an extended class (one that cannot be represented by a bitmap
1942        because it contains high-valued characters or Unicode property items, e.g.
1943        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1944        pattern, but PCRE should not loop if you do not (it no longer does).
1945        [Detail: two cases were found: (a) a repeated subpattern containing an
1946        extended class; (b) a recursive reference to a subpattern that followed a
1947        previous extended class. It wasn't skipping over the extended class
1948        correctly when UTF-8 mode was not set.]
1950     5. A negated single-character class was not being recognized as fixed-length
1951        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1952        compile error "lookbehind assertion is not fixed length".
1954     6. The RunPerlTest auxiliary script was showing an unexpected difference
1955        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1956        write a Perl script that can interpret lines of an input file either as
1957        byte characters or as UTF-8, which is what "perltest" was being required to
1958        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1959        can't do is switch easily at run time between having the "use utf8;" pragma
1960        or not. In the end, I fudged it by using the RunPerlTest script to insert
1961        "use utf8;" explicitly for the UTF-8 tests.
1963     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1964        the end of the subject string, contrary to the documentation and to what
1965        Perl does. This was true of both matching functions. Now it matches only at
1966        the start of the subject and immediately after *internal* newlines.
1968     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1969        a pointer to an int instead of a pointer to an unsigned long int. This
1970        caused problems on 64-bit systems.
1972     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1973        instance of the 'standard' template library not being so standard".
1975    10. There was no check on the number of named subpatterns nor the maximum
1976        length of a subpattern name. The product of these values is used to compute
1977        the size of the memory block for a compiled pattern. By supplying a very
1978        long subpattern name and a large number of named subpatterns, the size
1979        computation could be caused to overflow. This is now prevented by limiting
1980        the length of names to 32 characters, and the number of named subpatterns
1981        to 10,000.
1983    11. Subpatterns that are repeated with specific counts have to be replicated in
1984        the compiled pattern. The size of memory for this was computed from the
1985        length of the subpattern and the repeat count. The latter is limited to
1986        65535, but there was no limit on the former, meaning that integer overflow
1987        could in principle occur. The compiled length of a repeated subpattern is
1988        now limited to 30,000 bytes in order to prevent this.
1990    12. Added the optional facility to have named substrings with the same name.
1992    13. Added the ability to use a named substring as a condition, using the
1993        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1994        are numbers (not recommended). Forward references are permitted.
1996    14. Added forward references in named backreferences (if you see what I mean).
1998    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1999        pattern could run off the end of the subject. For example, the pattern
2000        "(?s)(.{1,5})"8 did this with the subject "ab".
2002    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2003        PCRE_CASELESS was set when matching characters that were quantified with ?
2004        or *.
2006    17. A character class other than a single negated character that had a minimum
2007        but no maximum quantifier - for example [ab]{6,} - was not handled
2008        correctly by pce_dfa_exec(). It would match only one character.
2010    18. A valid (though odd) pattern that looked like a POSIX character
2011        class but used an invalid character after [ (for example [[,abc,]]) caused
2012        pcre_compile() to give the error "Failed: internal error: code overflow" or
2013        in some cases to crash with a glibc free() error. This could even happen if
2014        the pattern terminated after [[ but there just happened to be a sequence of
2015        letters, a binary zero, and a closing ] in the memory that followed.
2017    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2018        over the years. Originally (before any Unicode support), just the bottom 8
2019        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2020        output from "man perlunicode" includes this:
2022          The regular expression compiler produces polymorphic opcodes.  That
2023          is, the pattern adapts to the data and automatically switches to
2024          the Unicode character scheme when presented with Unicode data--or
2025          instead uses a traditional byte scheme when presented with byte
2026          data.
2028        Sadly, a wide octal escape does not cause a switch, and in a string with
2029        no other multibyte characters, these octal escapes are treated as before.
2030        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2031        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2032        Unicode string.
2034        I have not perpetrated such confusion in PCRE. Up till now, it took just
2035        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2036        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2037        translate to the appropriate multibyte character.
2039    29. Applied some refactoring to reduce the number of warnings from Microsoft
2040        and Borland compilers. This has included removing the fudge introduced
2041        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2042        a warning about an unused variable.
2044    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2045        characters since release 4.0, because Perl (from release 5.004) does not.
2046        [Or at least, is documented not to: some releases seem to be in conflict
2047        with the documentation.] However, when a pattern was studied with
2048        pcre_study() and all its branches started with \s, PCRE still included VT
2049        as a possible starting character. Of course, this did no harm; it just
2050        caused an unnecessary match attempt.
2052    22. Removed a now-redundant internal flag bit that recorded the fact that case
2053        dependency changed within the pattern. This was once needed for "required
2054        byte" processing, but is no longer used. This recovers a now-scarce options
2055        bit. Also moved the least significant internal flag bit to the most-
2056        significant bit of the word, which was not previously used (hangover from
2057        the days when it was an int rather than a uint) to free up another bit for
2058        the future.
2060    23. Added support for CRLF line endings as well as CR and LF. As well as the
2061        default being selectable at build time, it can now be changed at runtime
2062        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2063        specify that it is scanning data with non-default line endings.
2065    24. Changed the definition of CXXLINK to make it agree with the definition of
2066        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2068    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2069        recursions. This makes a big different to stack usage for some patterns.
2071    26. If a subpattern containing a named recursion or subroutine reference such
2072        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2073        the space required for the compiled pattern went wrong and gave too small a
2074        value. Depending on the environment, this could lead to "Failed: internal
2075        error: code overflow at offset 49" or "glibc detected double free or
2076        corruption" errors.
2078    27. Applied patches from Google (a) to support the new newline modes and (b) to
2079        advance over multibyte UTF-8 characters in GlobalReplace.
2081    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2082        difference for some implementation of PCRE in some Windows version.
2084    29. Added some extra testing facilities to pcretest:
2086        \q<number>   in a data line sets the "match limit" value
2087        \Q<number>   in a data line sets the "match recursion limt" value
2088        -S <number>  sets the stack size, where <number> is in megabytes
2090        The -S option isn't available for Windows.
2093    Version 6.6 06-Feb-06
2094    ---------------------
2096     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2097        in pcreposix.h. I have copied the definition from pcre.h.
2099     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2100        because pcre.h is no longer a built file.
2102     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2103        not normally included in the compiled code.
2106    Version 6.5 01-Feb-06
2107    ---------------------
2109     1. When using the partial match feature with pcre_dfa_exec(), it was not
2110        anchoring the second and subsequent partial matches at the new starting
2111        point. This could lead to incorrect results. For example, with the pattern
2112        /1234/, partially matching against "123" and then "a4" gave a match.
2114     2. Changes to pcregrep:
2116        (a) All non-match returns from pcre_exec() were being treated as failures
2117            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2118            error message is output. Some extra information is given for the
2119            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2120            probably the only errors that are likely to be caused by users (by
2121            specifying a regex that has nested indefinite repeats, for instance).
2122            If there are more than 20 of these errors, pcregrep is abandoned.
2124        (b) A binary zero was treated as data while matching, but terminated the
2125            output line if it was written out. This has been fixed: binary zeroes
2126            are now no different to any other data bytes.
2128        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2129            used to set a locale for matching. The --locale=xxxx long option has
2130            been added (no short equivalent) to specify a locale explicitly on the
2131            pcregrep command, overriding the environment variables.
2133        (d) When -B was used with -n, some line numbers in the output were one less
2134            than they should have been.
2136        (e) Added the -o (--only-matching) option.
2138        (f) If -A or -C was used with -c (count only), some lines of context were
2139            accidentally printed for the final match.
2141        (g) Added the -H (--with-filename) option.
2143        (h) The combination of options -rh failed to suppress file names for files
2144            that were found from directory arguments.
2146        (i) Added the -D (--devices) and -d (--directories) options.
2148        (j) Added the -F (--fixed-strings) option.
2150        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2152        (l) Added the --colo(u)r option.
2154        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2155            is not present by default.
2157     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2158        items such as (?R) or (?1), when the recursion could match a number of
2159        alternatives. If it matched one of the alternatives, but subsequently,
2160        outside the recursion, there was a failure, the code tried to back up into
2161        the recursion. However, because of the way PCRE is implemented, this is not
2162        possible, and the result was an incorrect result from the match.
2164        In order to prevent this happening, the specification of recursion has
2165        been changed so that all such subpatterns are automatically treated as
2166        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2168     4. I had overlooked the fact that, in some locales, there are characters for
2169        which isalpha() is true but neither isupper() nor islower() are true. In
2170        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2171        and ordfeminine) are like this. This affected the treatment of \w and \W
2172        when they appeared in character classes, but not when they appeared outside
2173        a character class. The bit map for "word" characters is now created
2174        separately from the results of isalnum() instead of just taking it from the
2175        upper, lower, and digit maps. (Plus the underscore character, of course.)
2177     5. The above bug also affected the handling of POSIX character classes such as
2178        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2179        permanent tables. Instead, the bit maps for such a class were previously
2180        created as the appropriate unions of the upper, lower, and digit bitmaps.
2181        Now they are created by subtraction from the [[:word:]] class, which has
2182        its own bitmap.
2184     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2185        It is created by subtracting the vertical space characters (\x09, \x0a,
2186        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2187        subtraction was done in the overall bitmap for a character class, meaning
2188        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2189        be recognized. This bug has been fixed.
2191     7. Patches from the folks at Google:
2193          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2194          real life, but is still worth protecting against".
2196          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2197          regular expressions".
2199          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2200          have it.
2202          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2203          "configure" and the latter not, in order to fix a problem somebody had
2204          with compiling the Arg class on HP-UX.
2206          (e) Improve the error-handling of the C++ wrapper a little bit.
2208          (f) New tests for checking recursion limiting.
2210     8. The pcre_memmove() function, which is used only if the environment does not
2211        have a standard memmove() function (and is therefore rarely compiled),
2212        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2213        returning a result (though PCRE never actually uses the result).
2215     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2216        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2217        returned instead of calling malloc() with an overflowing number that would
2218        most likely cause subsequent chaos.
2220    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2222    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2223        with this option is matched, the nmatch and pmatch options of regexec() are
2224        ignored.
2226    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2227        provided in case anyone wants to the the POSIX interface with UTF-8
2228        strings.
2230    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2231        C++ linking (needed for some HP-UX environments).
2233    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2234        (unused parameter) and in the pcre_printint() function (omitted "default"
2235        switch label when the default is to do nothing).
2237    15. Added some code to make it possible, when PCRE is compiled as a C++
2238        library, to replace subject pointers for pcre_exec() with a smart pointer
2239        class, thus making it possible to process discontinuous strings.
2241    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2242        much the same function. They were added by different people who were trying
2243        to make PCRE easy to compile on non-Unix systems. It has been suggested
2244        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2245        for compiling on Windows systems. I have therefore replaced it with
2246        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2247        defaults to "extern" for C or "extern C" for C++, which works fine on
2248        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2249        SCOPE with something explicit in config.h. In addition:
2251        (a) pcreposix.h still had just "extern" instead of either of these macros;
2252            I have replaced it with PCRE_DATA_SCOPE.
2254        (b) Functions such as _pcre_xclass(), which are internal to the library,
2255            but external in the C sense, all had PCRE_EXPORT in their definitions.
2256            This is apparently wrong for the Windows case, so I have removed it.
2257            (It makes no difference on Unix-like systems.)
2259    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2260        of recursive calls to match(). This is different to MATCH_LIMIT because
2261        that limits the total number of calls to match(), not all of which increase
2262        the depth of recursion. Limiting the recursion depth limits the amount of
2263        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2264        when PCRE is compiled, and changed at run time. A patch from Google adds
2265        this functionality to the C++ interface.
2267    18. Changes to the handling of Unicode character properties:
2269        (a) Updated the table to Unicode 4.1.0.
2271        (b) Recognize characters that are not in the table as "Cn" (undefined).
2273        (c) I revised the way the table is implemented to a much improved format
2274            which includes recognition of ranges. It now supports the ranges that
2275            are defined in UnicodeData.txt, and it also amalgamates other
2276            characters into ranges. This has reduced the number of entries in the
2277            table from around 16,000 to around 3,000, thus reducing its size
2278            considerably. I realized I did not need to use a tree structure after
2279            all - a binary chop search is just as efficient. Having reduced the
2280            number of entries, I extended their size from 6 bytes to 8 bytes to
2281            allow for more data.
2283        (d) Added support for Unicode script names via properties such as \p{Han}.
2285    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2286        matching that character.
2288    20. When matching a repeated Unicode property with a minimum greater than zero,
2289        (for example \pL{2,}), PCRE could look past the end of the subject if it
2290        reached it while seeking the minimum number of characters. This could
2291        happen only if some of the characters were more than one byte long, because
2292        there is a check for at least the minimum number of bytes.
2294    21. Refactored the implementation of \p and \P so as to be more general, to
2295        allow for more different types of property in future. This has changed the
2296        compiled form incompatibly. Anybody with saved compiled patterns that use
2297        \p or \P will have to recompile them.
2299    22. Added "Any" and "L&" to the supported property types.
2301    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2302        but give a compile time error if the value is greater than 0xff.
2304    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2305        accidentally not being installed or uninstalled.
2307    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2308        made were to insert the current release number. This seemed silly, because
2309        it made things harder for people building PCRE on systems that don't run
2310        "configure". I have turned pcre.h into a distributed file, no longer built
2311        by "configure", with the version identification directly included. There is
2312        no longer a pcre.h.in file.
2314        However, this change necessitated a change to the pcre-config script as
2315        well. It is built from pcre-config.in, and one of the substitutions was the
2316        release number. I have updated configure.ac so that ./configure now finds
2317        the release number by grepping pcre.h.
2319    26. Added the ability to run the tests under valgrind.
2322    Version 6.4 05-Sep-05
2323    ---------------------
2325     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2326        "--" to be printed when multiple files were scanned, even when none of the
2327        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2328        consider it to be a bug, and have restored the previous behaviour.
2330     2. A couple of code tidies to get rid of compiler warnings.
2332     3. The pcretest program used to cheat by referring to symbols in the library
2333        whose names begin with _pcre_. These are internal symbols that are not
2334        really supposed to be visible externally, and in some environments it is
2335        possible to suppress them. The cheating is now confined to including
2336        certain files from the library's source, which is a bit cleaner.
2338     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2339        file's purpose clearer.
2341     5. Reorganized pcre_ucp_findchar().
2344    Version 6.3 15-Aug-05
2345    ---------------------
2347     1. The file libpcre.pc.in did not have general read permission in the tarball.
2349     2. There were some problems when building without C++ support:
2351        (a) If C++ support was not built, "make install" and "make test" still
2352            tried to test it.
2354        (b) There were problems when the value of CXX was explicitly set. Some
2355            changes have been made to try to fix these, and ...
2357        (c) --disable-cpp can now be used to explicitly disable C++ support.
2359        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2360            backslash in a target when C++ was disabled. This confuses some
2361            versions of "make", apparently. Using an intermediate variable solves
2362            this. (Same for CPP_LOBJ.)
2364     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2365        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2366        necessary on certain architectures.
2368     4. Added a setting of -export-symbols-regex to the link command to remove
2369        those symbols that are exported in the C sense, but actually are local
2370        within the library, and not documented. Their names all begin with
2371        "_pcre_". This is not a perfect job, because (a) we have to except some
2372        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2373        available (and never for static libraries). I have made a note to try to
2374        find a way round (a) in the future.
2377  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
2378  ---------------------  ---------------------

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