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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.12 12-Jan-2011
5    ------------------------
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
10    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
11        --match-limit and --recursion-limit options (added for 8.11). In
12        particular, this made one of the standard tests crash. (The integer value
13        went into the wrong half of a long int.)
15    3.  If the --colour option was given to pcregrep with -v (invert match), it
16        did strange things, either producing crazy output, or crashing. It should,
17        of course, ignore a request for colour when reporting lines that do not
18        match.
21    Version 8.11 10-Dec-2010
22    ------------------------
24    1.  (*THEN) was not working properly if there were untried alternatives prior
25        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
26        backtracked to try for "b" instead of moving to the next alternative branch
27        at the same level (in this case, to look for "c"). The Perl documentation
28        is clear that when (*THEN) is backtracked onto, it goes to the "next
29        alternative in the innermost enclosing group".
31    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
32        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
33        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
34        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
35        (*THEN).
37    3.  If \s appeared in a character class, it removed the VT character from
38        the class, even if it had been included by some previous item, for example
39        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
40        of \s, but is part of the POSIX "space" class.)
42    4.  A partial match never returns an empty string (because you can always
43        match an empty string at the end of the subject); however the checking for
44        an empty string was starting at the "start of match" point. This has been
45        changed to the "earliest inspected character" point, because the returned
46        data for a partial match starts at this character. This means that, for
47        example, /(?<=abc)def/ gives a partial match for the subject "abc"
48        (previously it gave "no match").
50    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
51        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
52        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
53        has an implication that the given string is incomplete (because a partial
54        match is preferred over a full match). For this reason, these items now
55        give a partial match in this situation. [Aside: previously, the one case
56        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
57        match rather than a full match, which was wrong by the old rules, but is
58        now correct.]
60    6.  There was a bug in the handling of #-introduced comments, recognized when
61        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
62        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
63        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
64        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
65        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
66        places in pcre_compile().
68    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
69        comments when looking ahead for named forward references to subpatterns,
70        the only newline sequence it recognized was NL. It now handles newlines
71        according to the set newline convention.
73    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
74        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
75        cater for a lack of strerror(). These oversights have been fixed.
77    9.  Added --match-limit and --recursion-limit to pcregrep.
79    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
81    11. When the -o option was used, pcregrep was setting a return code of 1, even
82        when matches were found, and --line-buffered was not being honoured.
84    12. Added an optional parentheses number to the -o and --only-matching options
85        of pcregrep.
87    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
88        can match an empty string. The code to do it in pcretest and pcredemo
89        needed fixing:
91        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
92            only one byte after an empty string match just before CRLF (this case
93            just got forgotten; "any" and "anycrlf" were OK).
95        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
96            mode when an empty string match preceded an ASCII character followed by
97            a non-ASCII character. (The code for advancing by one character rather
98            than one byte was nonsense.)
100        (c) The pcredemo.c sample program did not have any code at all to handle
101            the cases when CRLF is a valid newline sequence.
103    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
104        as a starting offset was within the subject string. There is now a new
105        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
106        negative or greater than the length of the string. In order to test this,
107        pcretest is extended to allow the setting of negative starting offsets.
109    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
110        starting offset points to the beginning of a UTF-8 character was
111        unnecessarily clumsy. I tidied it up.
113    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
114        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
116    17. Nobody had reported that the --include_dir option, which was added in
117        release 7.7 should have been called --include-dir (hyphen, not underscore)
118        for compatibility with GNU grep. I have changed it to --include-dir, but
119        left --include_dir as an undocumented synonym, and the same for
120        --exclude-dir, though that is not available in GNU grep, at least as of
121        release 2.5.4.
123    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
124        characters from a string of bytes) have been redefined so as not to use
125        loops, in order to improve performance in some environments. At the same
126        time, I abstracted some of the common code into auxiliary macros to save
127        repetition (this should not affect the compiled code).
129    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
130        compile-time error is now given if \c is not followed by an ASCII
131        character, that is, a byte less than 128. (In EBCDIC mode, the code is
132        different, and any byte value is allowed.)
134    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
135        START_OPTIMIZE option, which is now allowed at compile time - but just
136        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
137        to pcregrep and other applications that have no direct access to PCRE
138        options. The new /Y option in pcretest sets this option when calling
139        pcre_compile().
141    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
142        back references. Groups containing recursive back references were forced to
143        be atomic by that change, but in the case of named groups, the amount of
144        memory required was incorrectly computed, leading to "Failed: internal
145        error: code overflow". This has been fixed.
147    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
148        pcretest.c, to avoid build problems in some Borland environments.
151    Version 8.10 25-Jun-2010
152    ------------------------
154    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
155        THEN.
157    2.  (*ACCEPT) was not working when inside an atomic group.
159    3.  Inside a character class, \B is treated as a literal by default, but
160        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
161        causes the error). The code is unchanged, but I tidied the documentation.
163    4.  Inside a character class, PCRE always treated \R and \X as literals,
164        whereas Perl faults them if its -w option is set. I have changed PCRE so
165        that it faults them when PCRE_EXTRA is set.
167    5.  Added support for \N, which always matches any character other than
168        newline. (It is the same as "." when PCRE_DOTALL is not set.)
170    6.  When compiling pcregrep with newer versions of gcc which may have
171        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
172        declared with attribute warn_unused_result" were given. Just casting the
173        result to (void) does not stop the warnings; a more elaborate fudge is
174        needed. I've used a macro to implement this.
176    7.  Minor change to pcretest.c to avoid a compiler warning.
178    8.  Added four artifical Unicode properties to help with an option to make
179        \s etc use properties (see next item). The new properties are: Xan
180        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
182    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
183        use Unicode properties. (*UCP) at the start of a pattern can be used to set
184        this option. Modified pcretest to add /W to test this facility. Added
185        REG_UCP to make it available via the POSIX interface.
187    10. Added --line-buffered to pcregrep.
189    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
190        studied, and the match started with a letter with a code point greater than
191        127 whose first byte was different to the first byte of the other case of
192        the letter, the other case of this starting letter was not recognized
193        (#976).
195    12. If a pattern that was studied started with a repeated Unicode property
196        test, for example, \p{Nd}+, there was the theoretical possibility of
197        setting up an incorrect bitmap of starting bytes, but fortunately it could
198        not have actually happened in practice until change 8 above was made (it
199        added property types that matched character-matching opcodes).
201    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
202        possible starting bytes for non-anchored patterns.
204    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
205        \R, and also a number of cases that involve Unicode properties, both
206        explicit and implicit when PCRE_UCP is set.
208    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
209        input, it could crash or give wrong results if characters with values
210        greater than 0xc0 were present in the subject string. (Detail: it assumed
211        UTF-8 input when processing these items.)
213    16. Added a lot of (int) casts to avoid compiler warnings in systems where
214        size_t is 64-bit (#991).
216    17. Added a check for running out of memory when PCRE is compiled with
217        --disable-stack-for-recursion (#990).
219    18. If the last data line in a file for pcretest does not have a newline on
220        the end, a newline was missing in the output.
222    19. The default pcre_chartables.c file recognizes only ASCII characters (values
223        less than 128) in its various bitmaps. However, there is a facility for
224        generating tables according to the current locale when PCRE is compiled. It
225        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
226        characters, are recognized by isspace() and therefore were getting set in
227        these tables, and indeed these tables seem to approximate to ISO 8859. This
228        caused a problem in UTF-8 mode when pcre_study() was used to create a list
229        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
230        which of course cannot start UTF-8 characters. I have changed the code so
231        that only real ASCII characters (less than 128) and the correct starting
232        bytes for UTF-8 encodings are set for characters greater than 127 when in
233        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
234        altogether.)
236    20. Added the /T option to pcretest so as to be able to run tests with non-
237        standard character tables, thus making it possible to include the tests
238        used for 19 above in the standard set of tests.
240    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
241        reference to a subpattern the other side of a comment that contains an
242        opening parenthesis caused either an internal compiling error, or a
243        reference to the wrong subpattern.
246    Version 8.02 19-Mar-2010
247    ------------------------
249    1.  The Unicode data tables have been updated to Unicode 5.2.0.
251    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
252        configured.
254    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
255        original author of that file, following a query about its status.
257    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
258        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
260    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
261        quantifier applied to a forward-referencing subroutine call, could compile
262        incorrect code or give the error "internal error: previously-checked
263        referenced subpattern not found".
265    6.  Both MS Visual Studio and Symbian OS have problems with initializing
266        variables to point to external functions. For these systems, therefore,
267        pcre_malloc etc. are now initialized to local functions that call the
268        relevant global functions.
270    7.  There were two entries missing in the vectors called coptable and poptable
271        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
272        I've fixed the data, and added a kludgy way of testing at compile time that
273        the lengths are correct (equal to the number of opcodes).
275    8.  Following on from 7, I added a similar kludge to check the length of the
276        eint vector in pcreposix.c.
278    9.  Error texts for pcre_compile() are held as one long string to avoid too
279        much relocation at load time. To find a text, the string is searched,
280        counting zeros. There was no check for running off the end of the string,
281        which could happen if a new error number was added without updating the
282        string.
284    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
286    11. \K was not working if it appeared in an atomic group or in a group that
287        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
288        \K is "not well defined" if used in an assertion. PCRE now accepts it if
289        the assertion is positive, but not if it is negative.
291    12. Change 11 fortuitously reduced the size of the stack frame used in the
292        "match()" function of pcre_exec.c by one pointer. Forthcoming
293        implementation of support for (*MARK) will need an extra pointer on the
294        stack; I have reserved it now, so that the stack frame size does not
295        decrease.
297    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
298        item in branch that calls a recursion is a subroutine call - as in the
299        second branch in the above example - was incorrectly given the compile-
300        time error "recursive call could loop indefinitely" because pcre_compile()
301        was not correctly checking the subroutine for matching a non-empty string.
303    14. The checks for overrunning compiling workspace could trigger after an
304        overrun had occurred. This is a "should never occur" error, but it can be
305        triggered by pathological patterns such as hundreds of nested parentheses.
306        The checks now trigger 100 bytes before the end of the workspace.
308    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
311    Version 8.01 19-Jan-2010
312    ------------------------
314    1.  If a pattern contained a conditional subpattern with only one branch (in
315        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
316        computed the wrong minimum data length (which is of course zero for such
317        subpatterns). This could cause incorrect "no match" results.
319    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
320        the pattern is reset in the first branch, pcre_compile() failed with
321        "internal error: code overflow at offset...". This happened only when
322        the reset was to the original external option setting. (An optimization
323        abstracts leading options settings into an external setting, which was the
324        cause of this.)
326    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
327        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
328        assertion pattern did not match (meaning that the assertion was true), it
329        was incorrectly treated as false if the SKIP had been reached during the
330        matching. This also applied to assertions used as conditions.
332    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
333        assertion subpattern, including such a pattern used as a condition,
334        unpredictable results occurred, instead of the error return
337    5.  The C++ GlobalReplace function was not working like Perl for the special
338        situation when an empty string is matched. It now does the fancy magic
339        stuff that is necessary.
341    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
342        removed. (These were left over from very, very early versions of PCRE.)
344    7.  Some cosmetic changes to the code to make life easier when compiling it
345        as part of something else:
347        (a) Change DEBUG to PCRE_DEBUG.
349        (b) In pcre_compile(), rename the member of the "branch_chain" structure
350            called "current" as "current_branch", to prevent a collision with the
351            Linux macro when compiled as a kernel module.
353        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
354            prevent a collision with the Linux macro when compiled as a kernel
355            module.
357    8.  In pcre_compile() there are some checks for integer overflows that used to
358        cast potentially large values to (double). This has been changed to that
359        when building, a check for int64_t is made, and if it is found, it is used
360        instead, thus avoiding the use of floating point arithmetic. (There is no
361        other use of FP in PCRE.) If int64_t is not found, the fallback is to
362        double.
364    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
365        2005 (difference between two addresses compared to an unsigned value).
367    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
368        custom one, because of the following reported problem in Windows:
370          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
371              under Win32.
372          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
373              therefore missing the function definition.
374          - The compiler thus generates a "C" signature for the test function.
375          - The linker fails to find the "C" function.
376          - PCRE fails to configure if asked to do so against libbz2.
378    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
379        messages were output:
381          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
382          rerunning libtoolize, to keep the correct libtool macros in-tree.
383          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
385        I have done both of these things.
387    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
388        most of the time, it *can* run out if it is given a pattern that contains a
389        runaway infinite recursion. I updated the discussion in the pcrestack man
390        page.
392    13. Now that we have gone to the x.xx style of version numbers, the minor
393        version may start with zero. Using 08 or 09 is a bad idea because users
394        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
395        interpreted as invalid octal numbers. I've updated the previous comment in
396        configure.ac, and also added a check that gives an error if 08 or 09 are
397        used.
399    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
400        causing partial matching to fail when the end of the subject matched \W
401        in a UTF-8 pattern where \W was quantified with a minimum of 3.
403    15. There were some discrepancies between the declarations in pcre_internal.h
404        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
405        their definitions. The declarations used "const uschar *" and the
406        definitions used USPTR. Even though USPTR is normally defined as "const
407        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
408        reported that: "This difference in casting confuses some C++ compilers, for
409        example, SunCC recognizes above declarations as different functions and
410        generates broken code for hbpcre." I have changed the declarations to use
411        USPTR.
413    16. GNU libtool is named differently on some systems. The autogen.sh script now
414        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
415        (FreeBSD).
417    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
418        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
419        comment: "Figure out how to create a longlong from a string: strtoll and
420        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
421        instance, but it only takes 2 args instead of 3!"
423    18. A subtle bug concerned with back references has been fixed by a change of
424        specification, with a corresponding code fix. A pattern such as
425        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
426        refers, was giving matches when it shouldn't. For example, xa=xaaa would
427        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
428        same bug. Such groups have to be quantified to be useful, or contained
429        inside another quantified group. (If there's no repetition, the reference
430        can never match.) The problem arises because, having left the group and
431        moved on to the rest of the pattern, a later failure that backtracks into
432        the group uses the captured value from the final iteration of the group
433        rather than the correct earlier one. I have fixed this in PCRE by forcing
434        any group that contains a reference to itself to be an atomic group; that
435        is, there cannot be any backtracking into it once it has completed. This is
436        similar to recursive and subroutine calls.
439    Version 8.00 19-Oct-09
440    ----------------------
442    1.  The table for translating pcre_compile() error codes into POSIX error codes
443        was out-of-date, and there was no check on the pcre_compile() error code
444        being within the table. This could lead to an OK return being given in
445        error.
447    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
448        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
449        in a Windows environment.
451    3.  The pcregrep --count option prints the count for each file even when it is
452        zero, as does GNU grep. However, pcregrep was also printing all files when
453        --files-with-matches was added. Now, when both options are given, it prints
454        counts only for those files that have at least one match. (GNU grep just
455        prints the file name in this circumstance, but including the count seems
456        more useful - otherwise, why use --count?) Also ensured that the
457        combination -clh just lists non-zero counts, with no names.
459    4.  The long form of the pcregrep -F option was incorrectly implemented as
460        --fixed_strings instead of --fixed-strings. This is an incompatible change,
461        but it seems right to fix it, and I didn't think it was worth preserving
462        the old behaviour.
464    5.  The command line items --regex=pattern and --regexp=pattern were not
465        recognized by pcregrep, which required --regex pattern or --regexp pattern
466        (with a space rather than an '='). The man page documented the '=' forms,
467        which are compatible with GNU grep; these now work.
469    6.  No libpcreposix.pc file was created for pkg-config; there was just
470        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
472    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
473        when UCP support is not needed, by modifying the Python script that
474        generates it from Unicode data files. This should not matter if the module
475        is correctly used as a library, but I received one complaint about 50K of
476        unwanted data. My guess is that the person linked everything into his
477        program rather than using a library. Anyway, it does no harm.
479    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
480        was a minimum greater than 1 for a wide character in a possessive
481        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
482        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
483        character. Chaos in the form of incorrect output or a compiling loop could
484        result.
486    9.  The restrictions on what a pattern can contain when partial matching is
487        requested for pcre_exec() have been removed. All patterns can now be
488        partially matched by this function. In addition, if there are at least two
489        slots in the offset vector, the offset of the earliest inspected character
490        for the match and the offset of the end of the subject are set in them when
491        PCRE_ERROR_PARTIAL is returned.
493    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
494        synonymous with PCRE_PARTIAL, for backwards compatibility, and
495        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
496        and may be more useful for multi-segment matching.
498    11. Partial matching with pcre_exec() is now more intuitive. A partial match
499        used to be given if ever the end of the subject was reached; now it is
500        given only if matching could not proceed because another character was
501        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
502        string "Z", which now yields "no match" instead of "partial match". In the
503        case of pcre_dfa_exec(), "no match" is given if every matching path for the
504        final character ended with (*FAIL).
506    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
507        if the pattern had a "must contain" character that was already found in the
508        earlier partial match, unless partial matching was again requested. For
509        example, with the pattern /dog.(body)?/, the "must contain" character is
510        "g". If the first part-match was for the string "dog", restarting with
511        "sbody" failed. This bug has been fixed.
513    13. The string returned by pcre_dfa_exec() after a partial match has been
514        changed so that it starts at the first inspected character rather than the
515        first character of the match. This makes a difference only if the pattern
516        starts with a lookbehind assertion or \b or \B (\K is not supported by
517        pcre_dfa_exec()). It's an incompatible change, but it makes the two
518        matching functions compatible, and I think it's the right thing to do.
520    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
521        so that the demonstration program is easily available in environments where
522        PCRE has not been installed from source.
524    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
525        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
526        library.
528    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
529        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
530        is not the first non-POSIX option to be added. Clearly some people find
531        these options useful.
533    17. If a caller to the POSIX matching function regexec() passes a non-zero
534        value for nmatch with a NULL value for pmatch, the value of
535        nmatch is forced to zero.
537    18. RunGrepTest did not have a test for the availability of the -u option of
538        the diff command, as RunTest does. It now checks in the same way as
539        RunTest, and also checks for the -b option.
541    19. If an odd number of negated classes containing just a single character
542        interposed, within parentheses, between a forward reference to a named
543        subpattern and the definition of the subpattern, compilation crashed with
544        an internal error, complaining that it could not find the referenced
545        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
546        [The bug was that it was starting one character too far in when skipping
547        over the character class, thus treating the ] as data rather than
548        terminating the class. This meant it could skip too much.]
550    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
551        /g option in pcretest when the pattern contains \K, which makes it possible
552        to have an empty string match not at the start, even when the pattern is
553        anchored. Updated pcretest and pcredemo to use this option.
555    21. If the maximum number of capturing subpatterns in a recursion was greater
556        than the maximum at the outer level, the higher number was returned, but
557        with unset values at the outer level. The correct (outer level) value is
558        now given.
560    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
561        PCRE did not set those parentheses (unlike Perl). I have now found a way to
562        make it do so. The string so far is captured, making this feature
563        compatible with Perl.
565    23. The tests have been re-organized, adding tests 11 and 12, to make it
566        possible to check the Perl 5.10 features against Perl 5.10.
568    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
569        pattern matches a fixed length string. PCRE did not allow this; now it
570        does. Neither allows recursion.
572    25. I finally figured out how to implement a request to provide the minimum
573        length of subject string that was needed in order to match a given pattern.
574        (It was back references and recursion that I had previously got hung up
575        on.) This code has now been added to pcre_study(); it finds a lower bound
576        to the length of subject needed. It is not necessarily the greatest lower
577        bound, but using it to avoid searching strings that are too short does give
578        some useful speed-ups. The value is available to calling programs via
579        pcre_fullinfo().
581    26. While implementing 25, I discovered to my embarrassment that pcretest had
582        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
583        study optimizations had never been tested with that matching function.
584        Oops. What is worse, even when it was passed study data, there was a bug in
585        pcre_dfa_exec() that meant it never actually used it. Double oops. There
586        were also very few tests of studied patterns with pcre_dfa_exec().
588    27. If (?| is used to create subpatterns with duplicate numbers, they are now
589        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
590        on the other side of the coin, they are no longer allowed to have different
591        names, because these cannot be distinguished in PCRE, and this has caused
592        confusion. (This is a difference from Perl.)
594    28. When duplicate subpattern names are present (necessarily with different
595        numbers, as required by 27 above), and a test is made by name in a
596        conditional pattern, either for a subpattern having been matched, or for
597        recursion in such a pattern, all the associated numbered subpatterns are
598        tested, and the overall condition is true if the condition is true for any
599        one of them. This is the way Perl works, and is also more like the way
600        testing by number works.
603    Version 7.9 11-Apr-09
604    ---------------------
606    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
607        (pcretest), all targets were linked against these libraries. This included
608        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
609        libraries. This caused unwanted dependencies to be created. This problem
610        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
611        pcretest is linked with readline.
613    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
614        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
615        moved outside it again, because FALSE and TRUE are already defined in AIX,
616        but BOOL is not.
618    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
619        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
621    4.  The pcregrep documentation said spaces were inserted as well as colons (or
622        hyphens) following file names and line numbers when outputting matching
623        lines. This is not true; no spaces are inserted. I have also clarified the
624        wording for the --colour (or --color) option.
626    5.  In pcregrep, when --colour was used with -o, the list of matching strings
627        was not coloured; this is different to GNU grep, so I have changed it to be
628        the same.
630    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
631        each matching line was coloured. Now it goes on to look for further matches
632        of any of the test patterns, which is the same behaviour as GNU grep.
634    7.  A pattern that could match an empty string could cause pcregrep to loop; it
635        doesn't make sense to accept an empty string match in pcregrep, so I have
636        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
637        seems to be how GNU grep behaves.
639    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
640        start or after a newline", because the conditional assertion was not being
641        correctly handled. The rule now is that both the assertion and what follows
642        in the first alternative must satisfy the test.
644    9.  If auto-callout was enabled in a pattern with a conditional group whose
645        condition was an assertion, PCRE could crash during matching, both with
646        pcre_exec() and pcre_dfa_exec().
648    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
649        used for matching.
651    11. Unicode property support in character classes was not working for
652        characters (bytes) greater than 127 when not in UTF-8 mode.
654    12. Added the -M command line option to pcretest.
656    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
658    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
660    16. Added comments and documentation about mis-use of no_arg in the C++
661        wrapper.
663    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
664        from Martin Jerabek that uses macro names for all relevant character and
665        string constants.
667    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
668        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
669        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
670        these, but not everybody uses configure.
672    19. A conditional group that had only one branch was not being correctly
673        recognized as an item that could match an empty string. This meant that an
674        enclosing group might also not be so recognized, causing infinite looping
675        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
676        with the subject "ab", where knowledge that the repeated group can match
677        nothing is needed in order to break the loop.
679    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
680        exec(), but without supplying a callout function, matching went wrong.
682    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
683        leak if the size of the offset vector was greater than 30. When the vector
684        is smaller, the saved offsets during recursion go onto a local stack
685        vector, but for larger vectors malloc() is used. It was failing to free
686        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
687        error, in fact).
689    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
690        heapframe that is used only when UTF-8 support is enabled. This caused no
691        problem, but was untidy.
693    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
694        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
695        included within another project.
697    24. Steven Van Ingelgem's patches to add more options to the CMake support,
698        slightly modified by me:
700          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
701              not building pcregrep.
703          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
704              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
706    25. Forward references, both numeric and by name, in patterns that made use of
707        duplicate group numbers, could behave incorrectly or give incorrect errors,
708        because when scanning forward to find the reference group, PCRE was not
709        taking into account the duplicate group numbers. A pattern such as
710        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
712    26. Changed a few more instances of "const unsigned char *" to USPTR, making
713        the feature of a custom pointer more persuasive (as requested by a user).
715    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
716        pcretest.c, inside #ifndefs, because it seems they are sometimes already
717        pre-defined.
719    28. Added support for (*UTF8) at the start of a pattern.
721    29. Arrange for flags added by the "release type" setting in CMake to be shown
722        in the configuration summary.
725    Version 7.8 05-Sep-08
726    ---------------------
728    1.  Replaced UCP searching code with optimized version as implemented for Ad
729        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
730        stage table and inline lookup instead of a function, giving speed ups of 2
731        to 5 times on some simple patterns that I tested. Permission was given to
732        distribute the MultiStage2.py script that generates the tables (it's not in
733        the tarball, but is in the Subversion repository).
735    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
736        scripts.
738    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
739        a group with a zero qualifier. The result of the study could be incorrect,
740        or the function might crash, depending on the pattern.
742    4.  Caseless matching was not working for non-ASCII characters in back
743        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
744        It now works when Unicode Property Support is available.
746    5.  In pcretest, an escape such as \x{de} in the data was always generating
747        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
748        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
749        truncation.
751    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
753    7.  Added two (int) casts to pcregrep when printing the difference of two
754        pointers, in case they are 64-bit values.
756    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
757        test 2 if it fails.
759    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
760        and a #define of that name to empty if it is not externally set. This is to
761        allow users of MSVC to set it if necessary.
763    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
764        the convenience functions in the pcre_get.c source file.
766    11. An option change at the start of a pattern that had top-level alternatives
767        could cause overwriting and/or a crash. This command provoked a crash in
768        some environments:
770          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
772        This potential security problem was recorded as CVE-2008-2371.
774    12. For a pattern where the match had to start at the beginning or immediately
775        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
776        pcre_dfa_exec() could read past the end of the passed subject if there was
777        no match. To help with detecting such bugs (e.g. with valgrind), I modified
778        pcretest so that it places the subject at the end of its malloc-ed buffer.
780    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
781        exec() might read past the end of the data buffer in UTF-8 mode.
783    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
784        the data contained the byte 0x85 as part of a UTF-8 character within its
785        first line. This applied both to normal and DFA matching.
787    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
788        /^[^d]*?$/8 failed to match "abc".
790    16. Added a missing copyright notice to pcrecpp_internal.h.
792    17. Make it more clear in the documentation that values returned from
793        pcre_exec() in ovector are byte offsets, not character counts.
795    18. Tidied a few places to stop certain compilers from issuing warnings.
797    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
798        supplied by Stefan Weber. I made a further small update for 7.8 because
799        there is a change of source arrangements: the pcre_searchfuncs.c module is
800        replaced by pcre_ucd.c.
803    Version 7.7 07-May-08
804    ---------------------
806    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
807        a string to a long long, pretend we don't even have a long long." This is
808        done by checking for the strtoq, strtoll, and _strtoi64 functions.
810    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
811        pre-7.6 versions, which defined a global no_arg variable instead of putting
812        it in the RE class. (See also #8 below.)
814    3.  Remove a line of dead code, identified by coverity and reported by Nuno
815        Lopes.
817    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
819        (1) The include/exclude patterns were being applied to the whole pathnames
820            of files, instead of just to the final components.
822        (2) If there was more than one level of directory, the subdirectories were
823            skipped unless they satisfied the include/exclude conditions. This is
824            inconsistent with GNU grep (and could even be seen as contrary to the
825            pcregrep specification - which I improved to make it absolutely clear).
826            The action now is always to scan all levels of directory, and just
827            apply the include/exclude patterns to regular files.
829    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
830        --exclude_dir in the tests to avoid scanning .svn directories.
832    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
833        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
834        doesn't support NULs in patterns.
836    7.  Added some missing "const"s to declarations of static tables in
837        pcre_compile.c and pcre_dfa_exec.c.
839    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
840        caused by fix #2  above. (Subsequently also a second patch to fix the
841        first patch. And a third patch - this was a messy problem.)
843    9.  Applied Craig's patch to remove the use of push_back().
845    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
846        matching function regexec().
848    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
849        which, however, unlike Perl's \g{...}, are subroutine calls, not back
850        references. PCRE supports relative numbers with this syntax (I don't think
851        Oniguruma does).
853    12. Previously, a group with a zero repeat such as (...){0} was completely
854        omitted from the compiled regex. However, this means that if the group
855        was called as a subroutine from elsewhere in the pattern, things went wrong
856        (an internal error was given). Such groups are now left in the compiled
857        pattern, with a new opcode that causes them to be skipped at execution
858        time.
860    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
861        to the way PCRE behaves:
863        (a) A lone ] character is dis-allowed (Perl treats it as data).
865        (b) A back reference to an unmatched subpattern matches an empty string
866            (Perl fails the current match path).
868        (c) A data ] in a character class must be notated as \] because if the
869            first data character in a class is ], it defines an empty class. (In
870            Perl it is not possible to have an empty class.) The empty class []
871            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
872            The negative empty class [^] matches any one character, independently
873            of the DOTALL setting.
875    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
876        non-existent subpattern following a character class starting with ']' and
877        containing () gave an internal compiling error instead of "reference to
878        non-existent subpattern". Fortunately, when the pattern did exist, the
879        compiled code was correct. (When scanning forwards to check for the
880        existencd of the subpattern, it was treating the data ']' as terminating
881        the class, so got the count wrong. When actually compiling, the reference
882        was subsequently set up correctly.)
884    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
885        it was being rejected as not supported by pcre_dfa_exec(), even though
886        other assertions are supported. I have made pcre_dfa_exec() support
887        (*FAIL).
889    16. The implementation of 13c above involved the invention of a new opcode,
890        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
891        cannot be changed at match time, I realized I could make a small
892        improvement to matching performance by compiling OP_ALLANY instead of
893        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
894        on the OP_ANY path.
896    17. Compiling pcretest on Windows with readline support failed without the
897        following two fixes: (1) Make the unistd.h include conditional on
898        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
900    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
901        ncurses library to be included for pcretest when ReadLine support is
902        requested, but also to allow for it to be overridden. This patch came from
903        Daniel Bergström.
905    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
906        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
907        any errors with the current Unicode tables. Thanks to Peter Kankowski for
908        spotting this.
911    Version 7.6 28-Jan-08
912    ---------------------
914    1.  A character class containing a very large number of characters with
915        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
916        overflow.
918    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
919        HAVE_LONG_LONG is not defined.
921    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
922        bring them up to date and include new features. This patch includes:
924        - Fixed PH's badly added libz and libbz2 support.
925        - Fixed a problem with static linking.
926        - Added pcredemo. [But later removed - see 7 below.]
927        - Fixed dftables problem and added an option.
928        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
929            HAVE_LONG_LONG.
930        - Added readline support for pcretest.
931        - Added an listing of the option settings after cmake has run.
933    4.  A user submitted a patch to Makefile that makes it easy to create
934        "pcre.dll" under mingw when using Configure/Make. I added stuff to
935        Makefile.am that cause it to include this special target, without
936        affecting anything else. Note that the same mingw target plus all
937        the other distribution libraries and programs are now supported
938        when configuring with CMake (see 6 below) instead of with
939        Configure/Make.
941    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
942        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
943        exported in the Windows port". It has not yet been confirmed that the patch
944        solves the problem, but it does no harm.
946    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
947        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
948        with CMake, and also correct the comment about stack recursion.
950    7.  Remove the automatic building of pcredemo from the ./configure system and
951        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
952        of a program that users should build themselves after PCRE is installed, so
953        building it automatically is not really right. What is more, it gave
954        trouble in some build environments.
956    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
959    Version 7.5 10-Jan-08
960    ---------------------
962    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
963        values in parens when parsing an RE using the C++ wrapper."
965    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
966        Characters greater than 255 were excluded from the class instead of being
967        included.
969    3.  The same bug as (2) above applied to negated POSIX classes such as
970        [:^space:].
972    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
973        defined or documented. It seems to have been a typo for PCRE_STATIC, so
974        I have changed it.
976    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
977        first named subpattern) and a construct such as (?&a) would reference the
978        first named subpattern whose name started with "a" (in other words, the
979        length check was missing). Both these problems are fixed. "Subpattern name
980        expected" is now given for (?&) (a zero-length name), and this patch also
981        makes it give the same error for \k'' (previously it complained that that
982        was a reference to a non-existent subpattern).
984    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
985        this is right because (?- can be followed by option settings as well as by
986        digits. I have, however, made the messages clearer.
988    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
989        than the number used in the conditional) now cause a compile-time error.
990        This is actually not compatible with Perl, which accepts such patterns, but
991        treats the conditional as always being FALSE (as PCRE used to), but it
992        seems to me that giving a diagnostic is better.
994    8.  Change "alphameric" to the more common word "alphanumeric" in comments
995        and messages.
997    9.  Fix two occurrences of "backslash" in comments that should have been
998        "backspace".
1000    10. Remove two redundant lines of code that can never be obeyed (their function
1001        was moved elsewhere).
1003    11. The program that makes PCRE's Unicode character property table had a bug
1004        which caused it to generate incorrect table entries for sequences of
1005        characters that have the same character type, but are in different scripts.
1006        It amalgamated them into a single range, with the script of the first of
1007        them. In other words, some characters were in the wrong script. There were
1008        thirteen such cases, affecting characters in the following ranges:
1010          U+002b0 - U+002c1
1011          U+0060c - U+0060d
1012          U+0061e - U+00612
1013          U+0064b - U+0065e
1014          U+0074d - U+0076d
1015          U+01800 - U+01805
1016          U+01d00 - U+01d77
1017          U+01d9b - U+01dbf
1018          U+0200b - U+0200f
1019          U+030fc - U+030fe
1020          U+03260 - U+0327f
1021          U+0fb46 - U+0fbb1
1022          U+10450 - U+1049d
1024    12. The -o option (show only the matching part of a line) for pcregrep was not
1025        compatible with GNU grep in that, if there was more than one match in a
1026        line, it showed only the first of them. It now behaves in the same way as
1027        GNU grep.
1029    13. If the -o and -v options were combined for pcregrep, it printed a blank
1030        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1031        does the same. The return code can be used to tell if there were any
1032        non-matching lines.
1034    14. Added --file-offsets and --line-offsets to pcregrep.
1036    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1037        infinitely looping recursion. The bug was that positive lookaheads were not
1038        being skipped when checking for a possible empty match (negative lookaheads
1039        and both kinds of lookbehind were skipped).
1041    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1042        inclusion of <windows.h> to before rather than after the definition of
1043        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1045    17. Specifying a possessive quantifier with a specific limit for a Unicode
1046        character property caused pcre_compile() to compile bad code, which led at
1047        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1048        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1049        caused the error; without that there was no problem.
1051    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1053    19. Added --enable-pcretest-libreadline.
1055    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1056        RE::GlobalReplace(). As a result, the number of replacements returned was
1057        double what it should be. I removed one of the increments, but Craig sent a
1058        later patch that removed the other one (the right fix) and added unit tests
1059        that check the return values (which was not done before).
1061    21. Several CMake things:
1063        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1064            the names libpcre and libpcreposix, not just pcre and pcreposix.
1066        (2) The above change means that pcretest and pcregrep are now correctly
1067            linked with the newly-built libraries, not previously installed ones.
1071    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1072        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1073        UTF-8 newline character). The key issue is that the pattern starts .*;
1074        this means that the match must be either at the beginning, or after a
1075        newline. The bug was in the code for advancing after a failed match and
1076        checking that the new position followed a newline. It was not taking
1077        account of UTF-8 characters correctly.
1079    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1080        character classes. PCRE was not treating the sequence [:...:] as a
1081        character class unless the ... were all letters. Perl, however, seems to
1082        allow any characters between [: and :], though of course it rejects as
1083        unknown any "names" that contain non-letters, because all the known class
1084        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1085        for example, whereas PCRE did not - it did not recognize a POSIX character
1086        class. This seemed a bit dangerous, so the code has been changed to be
1087        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1088        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1089        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1090        Perl does, and where it didn't before.
1092    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1093        Windows environments %n is disabled by default.
1096    Version 7.4 21-Sep-07
1097    ---------------------
1099    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1100        means that a class such as [\s] counted as "explicit reference to CR or
1101        LF". That isn't really right - the whole point of the change was to try to
1102        help when there was an actual mention of one of the two characters. So now
1103        the change happens only if \r or \n (or a literal CR or LF) character is
1104        encountered.
1106    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1107        of both had grown to the point where there were only 3 bits left.
1108        Fortunately, there was spare space in the data structure, and so I have
1109        moved the internal flags into a new 16-bit field to free up more option
1110        bits.
1112    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1113        but did not set the internal JCHANGED flag - either of these is enough to
1114        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1115        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1116        start sets both bits.
1118    4.  Added options (at build time, compile time, exec time) to change \R from
1119        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1121    5.  doc/pcresyntax.html was missing from the distribution.
1123    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1124        compatibility, even though it is no longer used.
1126    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1127        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1128        windows.h file is present (where different names are used). [This was
1129        reversed later after testing - see 16 below.]
1131    8.  Changed all #include <config.h> to #include "config.h". There were also
1132        some further <pcre.h> cases that I changed to "pcre.h".
1134    9.  When pcregrep was used with the --colour option, it missed the line ending
1135        sequence off the lines that it output.
1137    10. It was pointed out to me that arrays of string pointers cause lots of
1138        relocations when a shared library is dynamically loaded. A technique of
1139        using a single long string with a table of offsets can drastically reduce
1140        these. I have refactored PCRE in four places to do this. The result is
1141        dramatic:
1143          Originally:                          290
1144          After changing UCP table:            187
1145          After changing error message table:   43
1146          After changing table of "verbs"       36
1147          After changing table of Posix names   22
1149        Thanks to the folks working on Gregex for glib for this insight.
1151    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1152        unicode-properties was also set.
1154    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1156    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1157        checked only for CRLF.
1159    14. Added casts to pcretest.c to avoid compiler warnings.
1161    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1163    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1164        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1165        entirely. This removes changes made in 7 above.
1167    17. The CMake files have been updated, and there is now more information about
1168        building with CMake in the NON-UNIX-USE document.
1171    Version 7.3 28-Aug-07
1172    ---------------------
1174     1. In the rejigging of the build system that eventually resulted in 7.1, the
1175        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1176        brackets there is not right, since it causes compilers to look for an
1177        installed pcre.h, not the version that is in the source that is being
1178        compiled (which of course may be different). I have changed it back to:
1180          #include "pcre.h"
1182        I have a vague recollection that the change was concerned with compiling in
1183        different directories, but in the new build system, that is taken care of
1184        by the VPATH setting the Makefile.
1186     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1187        when the subject happened to end in the byte 0x85 (e.g. if the last
1188        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1189        characters but of course it shouldn't be taken as a newline when it is part
1190        of another character. The bug was that, for an unlimited repeat of . in
1191        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1192        characters when looking for a newline.
1194     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1196     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1197        in debug output.
1199     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1200        long printing in the pcrecpp unittest when running under MinGW.
1202     6. ESC_K was left out of the EBCDIC table.
1204     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1205        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1206        limit also applies to "virtual nesting" when a pattern is recursive, and in
1207        this case 1000 isn't so big. I have been able to remove this limit at the
1208        expense of backing off one optimization in certain circumstances. Normally,
1209        when pcre_exec() would call its internal match() function recursively and
1210        immediately return the result unconditionally, it uses a "tail recursion"
1211        feature to save stack. However, when a subpattern that can match an empty
1212        string has an unlimited repetition quantifier, it no longer makes this
1213        optimization. That gives it a stack frame in which to save the data for
1214        checking that an empty string has been matched. Previously this was taken
1215        from the 1000-entry workspace that had been reserved. So now there is no
1216        explicit limit, but more stack is used.
1218     8. Applied Daniel's patches to solve problems with the import/export magic
1219        syntax that is required for Windows, and which was going wrong for the
1220        pcreposix and pcrecpp parts of the library. These were overlooked when this
1221        problem was solved for the main library.
1223     9. There were some crude static tests to avoid integer overflow when computing
1224        the size of patterns that contain repeated groups with explicit upper
1225        limits. As the maximum quantifier is 65535, the maximum group length was
1226        set at 30,000 so that the product of these two numbers did not overflow a
1227        32-bit integer. However, it turns out that people want to use groups that
1228        are longer than 30,000 bytes (though not repeat them that many times).
1229        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1230        made it possible to implement the integer overflow checks in a much more
1231        dynamic way, which I have now done. The artificial limitation on group
1232        length has been removed - we now have only the limit on the total length of
1233        the compiled pattern, which depends on the LINK_SIZE setting.
1235    10. Fixed a bug in the documentation for get/copy named substring when
1236        duplicate names are permitted. If none of the named substrings are set, the
1237        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1238        empty string.
1240    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1241        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1242        because the ] is interpreted as the first data character and the
1243        terminating ] is not found. PCRE has been made compatible with Perl in this
1244        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1245        cause memory overwriting.
1247    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1248        string has been matched (to stop an infinite loop). It was not recognizing
1249        a conditional subpattern that could match an empty string if that
1250        subpattern was within another subpattern. For example, it looped when
1251        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1252        condition was not nested. This bug has been fixed.
1254    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1255        past the start of the subject in the presence of bytes with the top bit
1256        set, for example "\x8aBCD".
1258    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1259        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1261    14. Optimized (?!) to (*FAIL).
1263    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1264        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1265        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1266        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1267        does: it's just the validity check that is more restrictive.
1269    16. Inserted checks for integer overflows during escape sequence (backslash)
1270        processing, and also fixed erroneous offset values for syntax errors during
1271        backslash processing.
1273    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1274        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1276    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1277        caused an overrun.
1279    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1280        something other than just ASCII characters) inside a group that had an
1281        unlimited repeat caused a loop at compile time (while checking to see
1282        whether the group could match an empty string).
1284    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1285        [\P{Any}] did so. (Error in the code for printing property names.)
1287    21. An orphan \E inside a character class could cause a crash.
1289    22. A repeated capturing bracket such as (A)? could cause a wild memory
1290        reference during compilation.
1292    23. There are several functions in pcre_compile() that scan along a compiled
1293        expression for various reasons (e.g. to see if it's fixed length for look
1294        behind). There were bugs in these functions when a repeated \p or \P was
1295        present in the pattern. These operators have additional parameters compared
1296        with \d, etc, and these were not being taken into account when moving along
1297        the compiled data. Specifically:
1299        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1300            length.
1302        (b) An item such as \pL+ within a repeated group could cause crashes or
1303            loops.
1305        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1306            "reference to non-existent subpattern" error.
1308        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1310    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1311        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1313    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1315    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1316        character were causing crashes (broken optimization).
1318    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1319        \p or \P) caused a compile-time loop.
1321    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1322        break. For example, the unstudied pattern [\r\n]A does not match the string
1323        "\r\nA" because change 7.0/46 below moves the current point on by two
1324        characters after failing to match at the start. However, the pattern \nA
1325        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1326        the same is true. There doesn't seem any very clean way out of this, but
1327        what I have chosen to do makes the common cases work: PCRE now takes note
1328        of whether there can be an explicit match for \r or \n anywhere in the
1329        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1330        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1331        pattern has explicit CR or LF references.
1333    29. Added (*CR) etc for changing newline setting at start of pattern.
1336    Version 7.2 19-Jun-07
1337    ---------------------
1339     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1340        which is apparently normally available under Windows.
1342     2. Re-jig the pcregrep tests with different newline settings in an attempt
1343        to make them independent of the local environment's newline setting.
1345     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1347     4. Some of the "internals" tests were previously cut out when the link size
1348        was not 2, because the output contained actual offsets. The recent new
1349        "Z" feature of pcretest means that these can be cut out, making the tests
1350        usable with all link sizes.
1352     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1353        stack recursion. This gives a massive performance boost under BSD, but just
1354        a small improvement under Linux. However, it saves one field in the frame
1355        in all cases.
1357     6. Added more features from the forthcoming Perl 5.10:
1359        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1360            recursion call. It refers to the nth most recently opened parentheses.
1362        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1363            to be opened parentheses.
1365        (c) Conditions that refer to capturing parentheses can be specified
1366            relatively, for example, (?(-2)... or (?(+3)...
1368        (d) \K resets the start of the current match so that everything before
1369            is not part of it.
1371        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1373        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1374            reference syntax.
1376        (g) (?| introduces a group in which the numbering of parentheses in each
1377            alternative starts with the same number.
1379        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1381     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1384     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1385        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1386        for detecting groups that can match an empty string.
1388     9. A pattern with a very large number of alternatives (more than several
1389        hundred) was running out of internal workspace during the pre-compile
1390        phase, where pcre_compile() figures out how much memory will be needed. A
1391        bit of new cunning has reduced the workspace needed for groups with
1392        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1393        workspace instead of running out of the 4096 that are available.
1395    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1397    11. Applied patch from Google to remove an optimization that didn't quite work.
1398        The report of the bug said:
1400          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1401          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1402          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1404    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1405        it matched the wrong number of bytes.
1408    Version 7.1 24-Apr-07
1409    ---------------------
1411     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1412        that is more "standard", making use of automake and other Autotools. There
1413        is some re-arrangement of the files and adjustment of comments consequent
1414        on this.
1416     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1417        for recursive directory scanning broke on some systems because the files
1418        are not scanned in any specific order and on different systems the order
1419        was different. A call to "sort" has been inserted into RunGrepTest for the
1420        approprate test as a short-term fix. In the longer term there may be an
1421        alternative.
1423     3. I had an email from Eric Raymond about problems translating some of PCRE's
1424        man pages to HTML (despite the fact that I distribute HTML pages, some
1425        people do their own conversions for various reasons). The problems
1426        concerned the use of low-level troff macros .br and .in. I have therefore
1427        removed all such uses from the man pages (some were redundant, some could
1428        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1429        HTML has been updated to handle .nf/.fi and to complain if it encounters
1430        .br or .in.
1432     4. Updated comments in configure.ac that get placed in config.h.in and also
1433        arranged for config.h to be included in the distribution, with the name
1434        config.h.generic, for the benefit of those who have to compile without
1435        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1437     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1438        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1439        makevp.bat for the current PCRE, using the additional files
1440        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1442     6. A Windows user reported a minor discrepancy with test 2, which turned out
1443        to be caused by a trailing space on an input line that had got lost in his
1444        copy. The trailing space was an accident, so I've just removed it.
1446     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1447        that is needed.
1449     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1450        as "const" (a) because they are and (b) because it helps the PHP
1451        maintainers who have recently made a script to detect big data structures
1452        in the php code that should be moved to the .rodata section. I remembered
1453        to update Builducptable as well, so it won't revert if ucptable.h is ever
1454        re-created.
1456     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1457        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1458        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1459        support is not required. This saves 1.5-2K of code, which is important in
1460        some applications.
1462        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1463        so as not to refer to the tables, even though these functions will never be
1464        called when UTF-8 support is disabled. Otherwise there are problems with a
1465        shared library.
1467    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1469        (a) It was defining its arguments as char * instead of void *.
1471        (b) It was assuming that all moves were upwards in memory; this was true
1472            a long time ago when I wrote it, but is no longer the case.
1474        The emulated memove() is provided for those environments that have neither
1475        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1476        is clearly not the case, as these two bugs were recently reported.
1478    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1479        and Detrail to create the HTML documentation, the .txt form of the man
1480        pages, and it removes trailing spaces from listed files. It also creates
1481        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1482        case, it wraps all the #defines with #ifndefs. This script should be run
1483        before "make dist".
1485    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1486        with Unicode property support.
1488        (a) For a maximizing quantifier, if the two different cases of the
1489            character were of different lengths in their UTF-8 codings (there are
1490            some cases like this - I found 11), and the matching function had to
1491            back up over a mixture of the two cases, it incorrectly assumed they
1492            were both the same length.
1494        (b) When PCRE was configured to use the heap rather than the stack for
1495            recursion during matching, it was not correctly preserving the data for
1496            the other case of a UTF-8 character when checking ahead for a match
1497            while processing a minimizing repeat. If the check also involved
1498            matching a wide character, but failed, corruption could cause an
1499            erroneous result when trying to check for a repeat of the original
1500            character.
1502    13. Some tidying changes to the testing mechanism:
1504        (a) The RunTest script now detects the internal link size and whether there
1505            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1506            values substituted by "configure". (The RunGrepTest script already did
1507            this for UTF-8.) The configure.ac script no longer substitutes the
1508            relevant variables.
1510        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1511            with length and offset values. This means that the output is different
1512            for different internal link sizes. Test 2 is skipped for link sizes
1513            other than 2 because of this, bypassing the problem. Unfortunately,
1514            there was also a test in test 3 (the locale tests) that used /B and
1515            failed for link sizes other than 2. Rather than cut the whole test out,
1516            I have added a new /Z option to pcretest that replaces the length and
1517            offset values with spaces. This is now used to make test 3 independent
1518            of link size. (Test 2 will be tidied up later.)
1520    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1521        segmentation fault instead of returning the appropriate error message.
1523    15. In multiline mode when the newline sequence was set to "any", the pattern
1524        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1525        This doesn't seem right; it now treats the CRLF combination as the line
1526        ending, and so does not match in that case. It's only a pattern such as ^$
1527        that would hit this one: something like ^ABC$ would have failed after \r
1528        and then tried again after \r\n.
1530    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1531        in an attempt to make files that differ only in their line terminators
1532        compare equal. This works on Linux.
1534    17. Under certain error circumstances pcregrep might try to free random memory
1535        as it exited. This is now fixed, thanks to valgrind.
1537    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1538        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1539        was because its rules for how to advance for /g after matching an empty
1540        string at the end of a line did not allow for this case. They now check for
1541        it specially.
1543    20. pcretest is supposed to handle patterns and data of any length, by
1544        extending its buffers when necessary. It was getting this wrong when the
1545        buffer for a data line had to be extended.
1547    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1548        CRLF as a newline sequence.
1550    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1551        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1552        I have nevertheless tidied it up.
1554    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1556    24. Added a man page for pcre-config.
1559    Version 7.0 19-Dec-06
1560    ---------------------
1562     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1563        moving to gcc 4.1.1.
1565     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1566        sys/time.h, which is documented as needed for this function. It doesn't
1567        seem to matter on Linux, but it showed up on some releases of OS X.
1569     3. It seems that there are systems where bytes whose values are greater than
1570        127 match isprint() in the "C" locale. The "C" locale should be the
1571        default when a C program starts up. In most systems, only ASCII printing
1572        characters match isprint(). This difference caused the output from pcretest
1573        to vary, making some of the tests fail. I have changed pcretest so that:
1575        (a) When it is outputting text in the compiled version of a pattern, bytes
1576            other than 32-126 are always shown as hex escapes.
1578        (b) When it is outputting text that is a matched part of a subject string,
1579            it does the same, unless a different locale has been set for the match
1580            (using the /L modifier). In this case, it uses isprint() to decide.
1582     4. Fixed a major bug that caused incorrect computation of the amount of memory
1583        required for a compiled pattern when options that changed within the
1584        pattern affected the logic of the preliminary scan that determines the
1585        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1586        that the computed length was too small. The symptoms of this bug were
1587        either the PCRE error "internal error: code overflow" from pcre_compile(),
1588        or a glibc crash with a message such as "pcretest: free(): invalid next
1589        size (fast)". Examples of patterns that provoked this bug (shown in
1590        pcretest format) are:
1592          /(?-x: )/x
1593          /(?x)(?-x: \s*#\s*)/
1594          /((?i)[\x{c0}])/8
1595          /(?i:[\x{c0}])/8
1597        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1598        is now done differently.
1600     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1601        wrapper classes; (b) implement a new function in the C++ scanner that is
1602        more efficient than the old way of doing things because it avoids levels of
1603        recursion in the regex matching; (c) add a paragraph to the documentation
1604        for the FullMatch() function.
1606     6. The escape sequence \n was being treated as whatever was defined as
1607        "newline". Not only was this contrary to the documentation, which states
1608        that \n is character 10 (hex 0A), but it also went horribly wrong when
1609        "newline" was defined as CRLF. This has been fixed.
1611     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1612        was being set to -1 for the "end of line" case (supposedly a value that no
1613        character can have). Though this value is never used (the check for end of
1614        line is "zero bytes in current character"), it caused compiler complaints.
1615        I've changed it to 0xffffffff.
1617     8. In pcre_version.c, the version string was being built by a sequence of
1618        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1619        string (as it is for production releases) called a macro with an empty
1620        argument. The C standard says the result of this is undefined. The gcc
1621        compiler treats it as an empty string (which was what was wanted) but it is
1622        reported that Visual C gives an error. The source has been hacked around to
1623        avoid this problem.
1625     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1626        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1627        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1628        of them did).
1630    10. Originally, pcretest opened its input and output without "b"; then I was
1631        told that "b" was needed in some environments, so it was added for release
1632        5.0 to both the input and output. (It makes no difference on Unix-like
1633        systems.) Later I was told that it is wrong for the input on Windows. I've
1634        now abstracted the modes into two macros, to make it easier to fiddle with
1635        them, and removed "b" from the input mode under Windows.
1637    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1639    12. Added -help and --help to pcretest as an official way of being reminded
1640        of the options.
1642    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1643        and pcrecpp.cc because they annoy compilers at high warning levels.
1645    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1647    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1648        scripts are not C programs :-) and which was not noticed because it works
1649        on Linux.
1651    16. pcretest is supposed to handle any length of pattern and data line (as one
1652        line or as a continued sequence of lines) by extending its input buffer if
1653        necessary. This feature was broken for very long pattern lines, leading to
1654        a string of junk being passed to pcre_compile() if the pattern was longer
1655        than about 50K.
1657    17. I have done a major re-factoring of the way pcre_compile() computes the
1658        amount of memory needed for a compiled pattern. Previously, there was code
1659        that made a preliminary scan of the pattern in order to do this. That was
1660        OK when PCRE was new, but as the facilities have expanded, it has become
1661        harder and harder to keep it in step with the real compile phase, and there
1662        have been a number of bugs (see for example, 4 above). I have now found a
1663        cunning way of running the real compile function in a "fake" mode that
1664        enables it to compute how much memory it would need, while actually only
1665        ever using a few hundred bytes of working memory and without too many
1666        tests of the mode. This should make future maintenance and development
1667        easier. A side effect of this work is that the limit of 200 on the nesting
1668        depth of parentheses has been removed (though this was never a serious
1669        limitation, I suspect). However, there is a downside: pcre_compile() now
1670        runs more slowly than before (30% or more, depending on the pattern). I
1671        hope this isn't a big issue. There is no effect on runtime performance.
1673    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1674        newline (only possible for the last line of a file) and it was a
1675        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1677    19. Added additional timing features to pcretest. (1) The -tm option now times
1678        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1679        separate command line item, by a number that specifies the number of
1680        repeats to use when timing. The default is 50000; this gives better
1681        precision, but takes uncomfortably long for very large patterns.
1683    20. Extended pcre_study() to be more clever in cases where a branch of a
1684        subpattern has no definite first character. For example, (a*|b*)[cd] would
1685        previously give no result from pcre_study(). Now it recognizes that the
1686        first character must be a, b, c, or d.
1688    21. There was an incorrect error "recursive call could loop indefinitely" if
1689        a subpattern (or the entire pattern) that was being tested for matching an
1690        empty string contained only one non-empty item after a nested subpattern.
1691        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1692        incorrectly, because the \d was being skipped in the check.
1694    22. The pcretest program now has a new pattern option /B and a command line
1695        option -b, which is equivalent to adding /B to every pattern. This causes
1696        it to show the compiled bytecode, without the additional information that
1697        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1698        is the same as /B/I).
1700    23. A new optimization is now able automatically to treat some sequences such
1701        as a*b as a*+b. More specifically, if something simple (such as a character
1702        or a simple class like \d) has an unlimited quantifier, and is followed by
1703        something that cannot possibly match the quantified thing, the quantifier
1704        is automatically "possessified".
1706    24. A recursive reference to a subpattern whose number was greater than 39
1707        went wrong under certain circumstances in UTF-8 mode. This bug could also
1708        have affected the operation of pcre_study().
1710    25. Realized that a little bit of performance could be had by replacing
1711        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1713    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1715    27. Possessive quantifiers such as a++ were previously implemented by turning
1716        them into atomic groups such as ($>a+). Now they have their own opcodes,
1717        which improves performance. This includes the automatically created ones
1718        from 23 above.
1720    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1721        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1722        the first matched character to be a colon. This applied both to named and
1723        numbered groups.
1725    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1727    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1728        building PCRE on Windows easier, so I have included it in the distribution.
1730    31. There is now a check in pcretest against a ridiculously large number being
1731        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1732        loop, the loop is abandoned.
1734    32. Forward references to subpatterns in conditions such as (?(2)...) where
1735        subpattern 2 is defined later cause pcre_compile() to search forwards in
1736        the pattern for the relevant set of parentheses. This search went wrong
1737        when there were unescaped parentheses in a character class, parentheses
1738        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1740    33. "Subroutine" calls and backreferences were previously restricted to
1741        referencing subpatterns earlier in the regex. This restriction has now
1742        been removed.
1744    34. Added a number of extra features that are going to be in Perl 5.10. On the
1745        whole, these are just syntactic alternatives for features that PCRE had
1746        previously implemented using the Python syntax or my own invention. The
1747        other formats are all retained for compatibility.
1749        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1750            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1751            also .NET compatible.
1753        (b) A recursion or subroutine call to a named group can now be defined as
1754            (?&name) as well as (?P>name).
1756        (c) A backreference to a named group can now be defined as \k<name> or
1757            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1758            5.10, are also .NET compatible.
1760        (d) A conditional reference to a named group can now use the syntax
1761            (?(<name>) or (?('name') as well as (?(name).
1763        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1764            groups (named and numbered) that are never evaluated inline, but can be
1765            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1766            is always false. There may be only one alternative in such a group.
1768        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1769            as the simple (?(R). The condition is true only if the most recent
1770            recursion is that of the given number or name. It does not search out
1771            through the entire recursion stack.
1773        (g) The escape \gN or \g{N} has been added, where N is a positive or
1774            negative number, specifying an absolute or relative reference.
1776    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1777        some "unreachable code" warnings.
1779    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1780        things, this adds five new scripts.
1782    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1783        There were also incompatibilities regarding the handling of \Q..\E inside
1784        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1785        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1787    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1788        matches an empty string, and forcibly breaks the loop. There were bugs in
1789        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1790        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1791        separate and independent bugs (that affected different cases) have been
1792        fixed.
1794    39. Refactored the code to abolish the use of different opcodes for small
1795        capturing bracket numbers. This is a tidy that I avoided doing when I
1796        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1797        The new approach is not only tidier, it makes it possible to reduce the
1798        memory needed to fix the previous bug (38).
1800    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1801        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1802        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1803        mode.
1805    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1806        report.
1808    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1809        copy construction and assignment in the C++ wrapper.
1811    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1812        couple of bugs that could have given wrong results in the "--newline=crlf"
1813        case.
1815    44. Added a number of casts and did some reorganization of signed/unsigned int
1816        variables following suggestions from Dair Grant. Also renamed the variable
1817        "this" as "item" because it is a C++ keyword.
1819    45. Arranged for dftables to add
1821          #include "pcre_internal.h"
1823        to pcre_chartables.c because without it, gcc 4.x may remove the array
1824        definition from the final binary if PCRE is built into a static library and
1825        dead code stripping is activated.
1827    46. For an unanchored pattern, if a match attempt fails at the start of a
1828        newline sequence, and the newline setting is CRLF or ANY, and the next two
1829        characters are CRLF, advance by two characters instead of one.
1832    Version 6.7 04-Jul-06
1833    ---------------------
1835     1. In order to handle tests when input lines are enormously long, pcretest has
1836        been re-factored so that it automatically extends its buffers when
1837        necessary. The code is crude, but this _is_ just a test program. The
1838        default size has been increased from 32K to 50K.
1840     2. The code in pcre_study() was using the value of the re argument before
1841        testing it for NULL. (Of course, in any sensible call of the function, it
1842        won't be NULL.)
1844     3. The memmove() emulation function in pcre_internal.h, which is used on
1845        systems that lack both memmove() and bcopy() - that is, hardly ever -
1846        was missing a "static" storage class specifier.
1848     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1849        containing an extended class (one that cannot be represented by a bitmap
1850        because it contains high-valued characters or Unicode property items, e.g.
1851        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1852        pattern, but PCRE should not loop if you do not (it no longer does).
1853        [Detail: two cases were found: (a) a repeated subpattern containing an
1854        extended class; (b) a recursive reference to a subpattern that followed a
1855        previous extended class. It wasn't skipping over the extended class
1856        correctly when UTF-8 mode was not set.]
1858     5. A negated single-character class was not being recognized as fixed-length
1859        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1860        compile error "lookbehind assertion is not fixed length".
1862     6. The RunPerlTest auxiliary script was showing an unexpected difference
1863        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1864        write a Perl script that can interpret lines of an input file either as
1865        byte characters or as UTF-8, which is what "perltest" was being required to
1866        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1867        can't do is switch easily at run time between having the "use utf8;" pragma
1868        or not. In the end, I fudged it by using the RunPerlTest script to insert
1869        "use utf8;" explicitly for the UTF-8 tests.
1871     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1872        the end of the subject string, contrary to the documentation and to what
1873        Perl does. This was true of both matching functions. Now it matches only at
1874        the start of the subject and immediately after *internal* newlines.
1876     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1877        a pointer to an int instead of a pointer to an unsigned long int. This
1878        caused problems on 64-bit systems.
1880     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1881        instance of the 'standard' template library not being so standard".
1883    10. There was no check on the number of named subpatterns nor the maximum
1884        length of a subpattern name. The product of these values is used to compute
1885        the size of the memory block for a compiled pattern. By supplying a very
1886        long subpattern name and a large number of named subpatterns, the size
1887        computation could be caused to overflow. This is now prevented by limiting
1888        the length of names to 32 characters, and the number of named subpatterns
1889        to 10,000.
1891    11. Subpatterns that are repeated with specific counts have to be replicated in
1892        the compiled pattern. The size of memory for this was computed from the
1893        length of the subpattern and the repeat count. The latter is limited to
1894        65535, but there was no limit on the former, meaning that integer overflow
1895        could in principle occur. The compiled length of a repeated subpattern is
1896        now limited to 30,000 bytes in order to prevent this.
1898    12. Added the optional facility to have named substrings with the same name.
1900    13. Added the ability to use a named substring as a condition, using the
1901        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1902        are numbers (not recommended). Forward references are permitted.
1904    14. Added forward references in named backreferences (if you see what I mean).
1906    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1907        pattern could run off the end of the subject. For example, the pattern
1908        "(?s)(.{1,5})"8 did this with the subject "ab".
1910    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1911        PCRE_CASELESS was set when matching characters that were quantified with ?
1912        or *.
1914    17. A character class other than a single negated character that had a minimum
1915        but no maximum quantifier - for example [ab]{6,} - was not handled
1916        correctly by pce_dfa_exec(). It would match only one character.
1918    18. A valid (though odd) pattern that looked like a POSIX character
1919        class but used an invalid character after [ (for example [[,abc,]]) caused
1920        pcre_compile() to give the error "Failed: internal error: code overflow" or
1921        in some cases to crash with a glibc free() error. This could even happen if
1922        the pattern terminated after [[ but there just happened to be a sequence of
1923        letters, a binary zero, and a closing ] in the memory that followed.
1925    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1926        over the years. Originally (before any Unicode support), just the bottom 8
1927        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1928        output from "man perlunicode" includes this:
1930          The regular expression compiler produces polymorphic opcodes.  That
1931          is, the pattern adapts to the data and automatically switches to
1932          the Unicode character scheme when presented with Unicode data--or
1933          instead uses a traditional byte scheme when presented with byte
1934          data.
1936        Sadly, a wide octal escape does not cause a switch, and in a string with
1937        no other multibyte characters, these octal escapes are treated as before.
1938        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1939        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1940        Unicode string.
1942        I have not perpetrated such confusion in PCRE. Up till now, it took just
1943        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1944        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1945        translate to the appropriate multibyte character.
1947    29. Applied some refactoring to reduce the number of warnings from Microsoft
1948        and Borland compilers. This has included removing the fudge introduced
1949        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1950        a warning about an unused variable.
1952    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1953        characters since release 4.0, because Perl (from release 5.004) does not.
1954        [Or at least, is documented not to: some releases seem to be in conflict
1955        with the documentation.] However, when a pattern was studied with
1956        pcre_study() and all its branches started with \s, PCRE still included VT
1957        as a possible starting character. Of course, this did no harm; it just
1958        caused an unnecessary match attempt.
1960    22. Removed a now-redundant internal flag bit that recorded the fact that case
1961        dependency changed within the pattern. This was once needed for "required
1962        byte" processing, but is no longer used. This recovers a now-scarce options
1963        bit. Also moved the least significant internal flag bit to the most-
1964        significant bit of the word, which was not previously used (hangover from
1965        the days when it was an int rather than a uint) to free up another bit for
1966        the future.
1968    23. Added support for CRLF line endings as well as CR and LF. As well as the
1969        default being selectable at build time, it can now be changed at runtime
1970        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1971        specify that it is scanning data with non-default line endings.
1973    24. Changed the definition of CXXLINK to make it agree with the definition of
1974        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1976    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1977        recursions. This makes a big different to stack usage for some patterns.
1979    26. If a subpattern containing a named recursion or subroutine reference such
1980        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1981        the space required for the compiled pattern went wrong and gave too small a
1982        value. Depending on the environment, this could lead to "Failed: internal
1983        error: code overflow at offset 49" or "glibc detected double free or
1984        corruption" errors.
1986    27. Applied patches from Google (a) to support the new newline modes and (b) to
1987        advance over multibyte UTF-8 characters in GlobalReplace.
1989    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1990        difference for some implementation of PCRE in some Windows version.
1992    29. Added some extra testing facilities to pcretest:
1994        \q<number>   in a data line sets the "match limit" value
1995        \Q<number>   in a data line sets the "match recursion limt" value
1996        -S <number>  sets the stack size, where <number> is in megabytes
1998        The -S option isn't available for Windows.
2001    Version 6.6 06-Feb-06
2002    ---------------------
2004     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2005        in pcreposix.h. I have copied the definition from pcre.h.
2007     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2008        because pcre.h is no longer a built file.
2010     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2011        not normally included in the compiled code.
2014    Version 6.5 01-Feb-06
2015    ---------------------
2017     1. When using the partial match feature with pcre_dfa_exec(), it was not
2018        anchoring the second and subsequent partial matches at the new starting
2019        point. This could lead to incorrect results. For example, with the pattern
2020        /1234/, partially matching against "123" and then "a4" gave a match.
2022     2. Changes to pcregrep:
2024        (a) All non-match returns from pcre_exec() were being treated as failures
2025            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2026            error message is output. Some extra information is given for the
2027            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2028            probably the only errors that are likely to be caused by users (by
2029            specifying a regex that has nested indefinite repeats, for instance).
2030            If there are more than 20 of these errors, pcregrep is abandoned.
2032        (b) A binary zero was treated as data while matching, but terminated the
2033            output line if it was written out. This has been fixed: binary zeroes
2034            are now no different to any other data bytes.
2036        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2037            used to set a locale for matching. The --locale=xxxx long option has
2038            been added (no short equivalent) to specify a locale explicitly on the
2039            pcregrep command, overriding the environment variables.
2041        (d) When -B was used with -n, some line numbers in the output were one less
2042            than they should have been.
2044        (e) Added the -o (--only-matching) option.
2046        (f) If -A or -C was used with -c (count only), some lines of context were
2047            accidentally printed for the final match.
2049        (g) Added the -H (--with-filename) option.
2051        (h) The combination of options -rh failed to suppress file names for files
2052            that were found from directory arguments.
2054        (i) Added the -D (--devices) and -d (--directories) options.
2056        (j) Added the -F (--fixed-strings) option.
2058        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2060        (l) Added the --colo(u)r option.
2062        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2063            is not present by default.
2065     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2066        items such as (?R) or (?1), when the recursion could match a number of
2067        alternatives. If it matched one of the alternatives, but subsequently,
2068        outside the recursion, there was a failure, the code tried to back up into
2069        the recursion. However, because of the way PCRE is implemented, this is not
2070        possible, and the result was an incorrect result from the match.
2072        In order to prevent this happening, the specification of recursion has
2073        been changed so that all such subpatterns are automatically treated as
2074        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2076     4. I had overlooked the fact that, in some locales, there are characters for
2077        which isalpha() is true but neither isupper() nor islower() are true. In
2078        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2079        and ordfeminine) are like this. This affected the treatment of \w and \W
2080        when they appeared in character classes, but not when they appeared outside
2081        a character class. The bit map for "word" characters is now created
2082        separately from the results of isalnum() instead of just taking it from the
2083        upper, lower, and digit maps. (Plus the underscore character, of course.)
2085     5. The above bug also affected the handling of POSIX character classes such as
2086        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2087        permanent tables. Instead, the bit maps for such a class were previously
2088        created as the appropriate unions of the upper, lower, and digit bitmaps.
2089        Now they are created by subtraction from the [[:word:]] class, which has
2090        its own bitmap.
2092     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2093        It is created by subtracting the vertical space characters (\x09, \x0a,
2094        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2095        subtraction was done in the overall bitmap for a character class, meaning
2096        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2097        be recognized. This bug has been fixed.
2099     7. Patches from the folks at Google:
2101          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2102          real life, but is still worth protecting against".
2104          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2105          regular expressions".
2107          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2108          have it.
2110          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2111          "configure" and the latter not, in order to fix a problem somebody had
2112          with compiling the Arg class on HP-UX.
2114          (e) Improve the error-handling of the C++ wrapper a little bit.
2116          (f) New tests for checking recursion limiting.
2118     8. The pcre_memmove() function, which is used only if the environment does not
2119        have a standard memmove() function (and is therefore rarely compiled),
2120        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2121        returning a result (though PCRE never actually uses the result).
2123     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2124        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2125        returned instead of calling malloc() with an overflowing number that would
2126        most likely cause subsequent chaos.
2128    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2130    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2131        with this option is matched, the nmatch and pmatch options of regexec() are
2132        ignored.
2134    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2135        provided in case anyone wants to the the POSIX interface with UTF-8
2136        strings.
2138    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2139        C++ linking (needed for some HP-UX environments).
2141    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2142        (unused parameter) and in the pcre_printint() function (omitted "default"
2143        switch label when the default is to do nothing).
2145    15. Added some code to make it possible, when PCRE is compiled as a C++
2146        library, to replace subject pointers for pcre_exec() with a smart pointer
2147        class, thus making it possible to process discontinuous strings.
2149    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2150        much the same function. They were added by different people who were trying
2151        to make PCRE easy to compile on non-Unix systems. It has been suggested
2152        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2153        for compiling on Windows systems. I have therefore replaced it with
2154        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2155        defaults to "extern" for C or "extern C" for C++, which works fine on
2156        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2157        SCOPE with something explicit in config.h. In addition:
2159        (a) pcreposix.h still had just "extern" instead of either of these macros;
2160            I have replaced it with PCRE_DATA_SCOPE.
2162        (b) Functions such as _pcre_xclass(), which are internal to the library,
2163            but external in the C sense, all had PCRE_EXPORT in their definitions.
2164            This is apparently wrong for the Windows case, so I have removed it.
2165            (It makes no difference on Unix-like systems.)
2167    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2168        of recursive calls to match(). This is different to MATCH_LIMIT because
2169        that limits the total number of calls to match(), not all of which increase
2170        the depth of recursion. Limiting the recursion depth limits the amount of
2171        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2172        when PCRE is compiled, and changed at run time. A patch from Google adds
2173        this functionality to the C++ interface.
2175    18. Changes to the handling of Unicode character properties:
2177        (a) Updated the table to Unicode 4.1.0.
2179        (b) Recognize characters that are not in the table as "Cn" (undefined).
2181        (c) I revised the way the table is implemented to a much improved format
2182            which includes recognition of ranges. It now supports the ranges that
2183            are defined in UnicodeData.txt, and it also amalgamates other
2184            characters into ranges. This has reduced the number of entries in the
2185            table from around 16,000 to around 3,000, thus reducing its size
2186            considerably. I realized I did not need to use a tree structure after
2187            all - a binary chop search is just as efficient. Having reduced the
2188            number of entries, I extended their size from 6 bytes to 8 bytes to
2189            allow for more data.
2191        (d) Added support for Unicode script names via properties such as \p{Han}.
2193    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2194        matching that character.
2196    20. When matching a repeated Unicode property with a minimum greater than zero,
2197        (for example \pL{2,}), PCRE could look past the end of the subject if it
2198        reached it while seeking the minimum number of characters. This could
2199        happen only if some of the characters were more than one byte long, because
2200        there is a check for at least the minimum number of bytes.
2202    21. Refactored the implementation of \p and \P so as to be more general, to
2203        allow for more different types of property in future. This has changed the
2204        compiled form incompatibly. Anybody with saved compiled patterns that use
2205        \p or \P will have to recompile them.
2207    22. Added "Any" and "L&" to the supported property types.
2209    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2210        but give a compile time error if the value is greater than 0xff.
2212    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2213        accidentally not being installed or uninstalled.
2215    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2216        made were to insert the current release number. This seemed silly, because
2217        it made things harder for people building PCRE on systems that don't run
2218        "configure". I have turned pcre.h into a distributed file, no longer built
2219        by "configure", with the version identification directly included. There is
2220        no longer a pcre.h.in file.
2222        However, this change necessitated a change to the pcre-config script as
2223        well. It is built from pcre-config.in, and one of the substitutions was the
2224        release number. I have updated configure.ac so that ./configure now finds
2225        the release number by grepping pcre.h.
2227    26. Added the ability to run the tests under valgrind.
2230    Version 6.4 05-Sep-05
2231    ---------------------
2233     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2234        "--" to be printed when multiple files were scanned, even when none of the
2235        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2236        consider it to be a bug, and have restored the previous behaviour.
2238     2. A couple of code tidies to get rid of compiler warnings.
2240     3. The pcretest program used to cheat by referring to symbols in the library
2241        whose names begin with _pcre_. These are internal symbols that are not
2242        really supposed to be visible externally, and in some environments it is
2243        possible to suppress them. The cheating is now confined to including
2244        certain files from the library's source, which is a bit cleaner.
2246     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2247        file's purpose clearer.
2249     5. Reorganized pcre_ucp_findchar().
2252    Version 6.3 15-Aug-05
2253    ---------------------
2255     1. The file libpcre.pc.in did not have general read permission in the tarball.
2257     2. There were some problems when building without C++ support:
2259        (a) If C++ support was not built, "make install" and "make test" still
2260            tried to test it.
2262        (b) There were problems when the value of CXX was explicitly set. Some
2263            changes have been made to try to fix these, and ...
2265        (c) --disable-cpp can now be used to explicitly disable C++ support.
2267        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2268            backslash in a target when C++ was disabled. This confuses some
2269            versions of "make", apparently. Using an intermediate variable solves
2270            this. (Same for CPP_LOBJ.)
2272     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2273        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2274        necessary on certain architectures.
2276     4. Added a setting of -export-symbols-regex to the link command to remove
2277        those symbols that are exported in the C sense, but actually are local
2278        within the library, and not documented. Their names all begin with
2279        "_pcre_". This is not a perfect job, because (a) we have to except some
2280        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2281        available (and never for static libraries). I have made a note to try to
2282        find a way round (a) in the future.
2285  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
2286  ---------------------  ---------------------

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