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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.5 12-Nov-07  Version 8.11 10-Oct-2010
5    ------------------------
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
20    3.  If \s appeared in a character class, it removed the VT character from
21        the class, even if it had been included by some previous item, for example
22        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23        of \s, but is part of the POSIX "space" class.)
25    4.  A partial match never returns an empty string (because you can always
26        match an empty string at the end of the subject); however the checking for
27        an empty string was starting at the "start of match" point. This has been
28        changed to the "earliest inspected character" point, because the returned
29        data for a partial match starts at this character. This means that, for
30        example, /(?<=abc)def/ gives a partial match for the subject "abc"
31        (previously it gave "no match").
33    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36        has an implication that the given string is incomplete (because a partial
37        match is preferred over a full match). For this reason, these items now
38        give a partial match in this situation. [Aside: previously, the one case
39        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40        match rather than a full match, which was wrong by the old rules, but is
41        now correct.]
43    6.  There was a bug in the handling of #-introduced comments, recognized when
44        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49        places in pcre_compile().
51    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
52        comments when looking ahead for named forward references to subpatterns,
53        the only newline sequence it recognized was NL. It now handles newlines
54        according to the set newline convention.
56    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
57        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
58        cater for a lack of strerror(). These oversights have been fixed.
60    9.  Added --match-limit and --recursion-limit to pcregrep.
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
64    11. When the -o option was used, pcregrep was setting a return code of 1, even
65        when matches were found, and --line-buffered was not being honoured.
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
70    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
71        can match an empty string. The code to do it in pcretest and pcredemo
72        needed fixing:
74        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
75            only one byte after an empty string match just before CRLF (this case
76            just got forgotten; "any" and "anycrlf" were OK).
78        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
79            mode when an empty string match preceded an ASCII character followed by
80            a non-ASCII character. (The code for advancing by one character rather
81            than one byte was nonsense.)
83        (c) The pcredemo.c sample program did not have any code at all to handle
84            the cases when CRLF is a valid newline sequence.
86    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
87        as a starting offset was within the subject string. There is now a new
88        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
89        negative or greater than the length of the string. In order to test this,
90        pcretest is extended to allow the setting of negative starting offsets.
92    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
93        starting offset points to the beginning of a UTF-8 character was
94        unnecessarily clumsy. I tidied it up.
97    Version 8.10 25-Jun-2010
98    ------------------------
100    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
101        THEN.
103    2.  (*ACCEPT) was not working when inside an atomic group.
105    3.  Inside a character class, \B is treated as a literal by default, but
106        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
107        causes the error). The code is unchanged, but I tidied the documentation.
109    4.  Inside a character class, PCRE always treated \R and \X as literals,
110        whereas Perl faults them if its -w option is set. I have changed PCRE so
111        that it faults them when PCRE_EXTRA is set.
113    5.  Added support for \N, which always matches any character other than
114        newline. (It is the same as "." when PCRE_DOTALL is not set.)
116    6.  When compiling pcregrep with newer versions of gcc which may have
117        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
118        declared with attribute warn_unused_result" were given. Just casting the
119        result to (void) does not stop the warnings; a more elaborate fudge is
120        needed. I've used a macro to implement this.
122    7.  Minor change to pcretest.c to avoid a compiler warning.
124    8.  Added four artifical Unicode properties to help with an option to make
125        \s etc use properties (see next item). The new properties are: Xan
126        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
128    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
129        use Unicode properties. (*UCP) at the start of a pattern can be used to set
130        this option. Modified pcretest to add /W to test this facility. Added
131        REG_UCP to make it available via the POSIX interface.
133    10. Added --line-buffered to pcregrep.
135    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
136        studied, and the match started with a letter with a code point greater than
137        127 whose first byte was different to the first byte of the other case of
138        the letter, the other case of this starting letter was not recognized
139        (#976).
141    12. If a pattern that was studied started with a repeated Unicode property
142        test, for example, \p{Nd}+, there was the theoretical possibility of
143        setting up an incorrect bitmap of starting bytes, but fortunately it could
144        not have actually happened in practice until change 8 above was made (it
145        added property types that matched character-matching opcodes).
147    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
148        possible starting bytes for non-anchored patterns.
150    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
151        \R, and also a number of cases that involve Unicode properties, both
152        explicit and implicit when PCRE_UCP is set.
154    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
155        input, it could crash or give wrong results if characters with values
156        greater than 0xc0 were present in the subject string. (Detail: it assumed
157        UTF-8 input when processing these items.)
159    16. Added a lot of (int) casts to avoid compiler warnings in systems where
160        size_t is 64-bit (#991).
162    17. Added a check for running out of memory when PCRE is compiled with
163        --disable-stack-for-recursion (#990).
165    18. If the last data line in a file for pcretest does not have a newline on
166        the end, a newline was missing in the output.
168    19. The default pcre_chartables.c file recognizes only ASCII characters (values
169        less than 128) in its various bitmaps. However, there is a facility for
170        generating tables according to the current locale when PCRE is compiled. It
171        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
172        characters, are recognized by isspace() and therefore were getting set in
173        these tables, and indeed these tables seem to approximate to ISO 8859. This
174        caused a problem in UTF-8 mode when pcre_study() was used to create a list
175        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
176        which of course cannot start UTF-8 characters. I have changed the code so
177        that only real ASCII characters (less than 128) and the correct starting
178        bytes for UTF-8 encodings are set for characters greater than 127 when in
179        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
180        altogether.)
182    20. Added the /T option to pcretest so as to be able to run tests with non-
183        standard character tables, thus making it possible to include the tests
184        used for 19 above in the standard set of tests.
186    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
187        reference to a subpattern the other side of a comment that contains an
188        opening parenthesis caused either an internal compiling error, or a
189        reference to the wrong subpattern.
192    Version 8.02 19-Mar-2010
193    ------------------------
195    1.  The Unicode data tables have been updated to Unicode 5.2.0.
197    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
198        configured.
200    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
201        original author of that file, following a query about its status.
203    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
204        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
206    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
207        quantifier applied to a forward-referencing subroutine call, could compile
208        incorrect code or give the error "internal error: previously-checked
209        referenced subpattern not found".
211    6.  Both MS Visual Studio and Symbian OS have problems with initializing
212        variables to point to external functions. For these systems, therefore,
213        pcre_malloc etc. are now initialized to local functions that call the
214        relevant global functions.
216    7.  There were two entries missing in the vectors called coptable and poptable
217        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
218        I've fixed the data, and added a kludgy way of testing at compile time that
219        the lengths are correct (equal to the number of opcodes).
221    8.  Following on from 7, I added a similar kludge to check the length of the
222        eint vector in pcreposix.c.
224    9.  Error texts for pcre_compile() are held as one long string to avoid too
225        much relocation at load time. To find a text, the string is searched,
226        counting zeros. There was no check for running off the end of the string,
227        which could happen if a new error number was added without updating the
228        string.
230    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
232    11. \K was not working if it appeared in an atomic group or in a group that
233        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
234        \K is "not well defined" if used in an assertion. PCRE now accepts it if
235        the assertion is positive, but not if it is negative.
237    12. Change 11 fortuitously reduced the size of the stack frame used in the
238        "match()" function of pcre_exec.c by one pointer. Forthcoming
239        implementation of support for (*MARK) will need an extra pointer on the
240        stack; I have reserved it now, so that the stack frame size does not
241        decrease.
243    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
244        item in branch that calls a recursion is a subroutine call - as in the
245        second branch in the above example - was incorrectly given the compile-
246        time error "recursive call could loop indefinitely" because pcre_compile()
247        was not correctly checking the subroutine for matching a non-empty string.
249    14. The checks for overrunning compiling workspace could trigger after an
250        overrun had occurred. This is a "should never occur" error, but it can be
251        triggered by pathological patterns such as hundreds of nested parentheses.
252        The checks now trigger 100 bytes before the end of the workspace.
254    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
257    Version 8.01 19-Jan-2010
258    ------------------------
260    1.  If a pattern contained a conditional subpattern with only one branch (in
261        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
262        computed the wrong minimum data length (which is of course zero for such
263        subpatterns). This could cause incorrect "no match" results.
265    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
266        the pattern is reset in the first branch, pcre_compile() failed with
267        "internal error: code overflow at offset...". This happened only when
268        the reset was to the original external option setting. (An optimization
269        abstracts leading options settings into an external setting, which was the
270        cause of this.)
272    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
273        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
274        assertion pattern did not match (meaning that the assertion was true), it
275        was incorrectly treated as false if the SKIP had been reached during the
276        matching. This also applied to assertions used as conditions.
278    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
279        assertion subpattern, including such a pattern used as a condition,
280        unpredictable results occurred, instead of the error return
283    5.  The C++ GlobalReplace function was not working like Perl for the special
284        situation when an empty string is matched. It now does the fancy magic
285        stuff that is necessary.
287    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
288        removed. (These were left over from very, very early versions of PCRE.)
290    7.  Some cosmetic changes to the code to make life easier when compiling it
291        as part of something else:
293        (a) Change DEBUG to PCRE_DEBUG.
295        (b) In pcre_compile(), rename the member of the "branch_chain" structure
296            called "current" as "current_branch", to prevent a collision with the
297            Linux macro when compiled as a kernel module.
299        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
300            prevent a collision with the Linux macro when compiled as a kernel
301            module.
303    8.  In pcre_compile() there are some checks for integer overflows that used to
304        cast potentially large values to (double). This has been changed to that
305        when building, a check for int64_t is made, and if it is found, it is used
306        instead, thus avoiding the use of floating point arithmetic. (There is no
307        other use of FP in PCRE.) If int64_t is not found, the fallback is to
308        double.
310    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
311        2005 (difference between two addresses compared to an unsigned value).
313    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
314        custom one, because of the following reported problem in Windows:
316          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
317              under Win32.
318          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
319              therefore missing the function definition.
320          - The compiler thus generates a "C" signature for the test function.
321          - The linker fails to find the "C" function.
322          - PCRE fails to configure if asked to do so against libbz2.
324    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
325        messages were output:
327          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
328          rerunning libtoolize, to keep the correct libtool macros in-tree.
329          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
331        I have done both of these things.
333    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
334        most of the time, it *can* run out if it is given a pattern that contains a
335        runaway infinite recursion. I updated the discussion in the pcrestack man
336        page.
338    13. Now that we have gone to the x.xx style of version numbers, the minor
339        version may start with zero. Using 08 or 09 is a bad idea because users
340        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
341        interpreted as invalid octal numbers. I've updated the previous comment in
342        configure.ac, and also added a check that gives an error if 08 or 09 are
343        used.
345    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
346        causing partial matching to fail when the end of the subject matched \W
347        in a UTF-8 pattern where \W was quantified with a minimum of 3.
349    15. There were some discrepancies between the declarations in pcre_internal.h
350        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
351        their definitions. The declarations used "const uschar *" and the
352        definitions used USPTR. Even though USPTR is normally defined as "const
353        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
354        reported that: "This difference in casting confuses some C++ compilers, for
355        example, SunCC recognizes above declarations as different functions and
356        generates broken code for hbpcre." I have changed the declarations to use
357        USPTR.
359    16. GNU libtool is named differently on some systems. The autogen.sh script now
360        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
361        (FreeBSD).
363    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
364        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
365        comment: "Figure out how to create a longlong from a string: strtoll and
366        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
367        instance, but it only takes 2 args instead of 3!"
369    18. A subtle bug concerned with back references has been fixed by a change of
370        specification, with a corresponding code fix. A pattern such as
371        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
372        refers, was giving matches when it shouldn't. For example, xa=xaaa would
373        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
374        same bug. Such groups have to be quantified to be useful, or contained
375        inside another quantified group. (If there's no repetition, the reference
376        can never match.) The problem arises because, having left the group and
377        moved on to the rest of the pattern, a later failure that backtracks into
378        the group uses the captured value from the final iteration of the group
379        rather than the correct earlier one. I have fixed this in PCRE by forcing
380        any group that contains a reference to itself to be an atomic group; that
381        is, there cannot be any backtracking into it once it has completed. This is
382        similar to recursive and subroutine calls.
385    Version 8.00 19-Oct-09
386    ----------------------
388    1.  The table for translating pcre_compile() error codes into POSIX error codes
389        was out-of-date, and there was no check on the pcre_compile() error code
390        being within the table. This could lead to an OK return being given in
391        error.
393    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
394        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
395        in a Windows environment.
397    3.  The pcregrep --count option prints the count for each file even when it is
398        zero, as does GNU grep. However, pcregrep was also printing all files when
399        --files-with-matches was added. Now, when both options are given, it prints
400        counts only for those files that have at least one match. (GNU grep just
401        prints the file name in this circumstance, but including the count seems
402        more useful - otherwise, why use --count?) Also ensured that the
403        combination -clh just lists non-zero counts, with no names.
405    4.  The long form of the pcregrep -F option was incorrectly implemented as
406        --fixed_strings instead of --fixed-strings. This is an incompatible change,
407        but it seems right to fix it, and I didn't think it was worth preserving
408        the old behaviour.
410    5.  The command line items --regex=pattern and --regexp=pattern were not
411        recognized by pcregrep, which required --regex pattern or --regexp pattern
412        (with a space rather than an '='). The man page documented the '=' forms,
413        which are compatible with GNU grep; these now work.
415    6.  No libpcreposix.pc file was created for pkg-config; there was just
416        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
418    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
419        when UCP support is not needed, by modifying the Python script that
420        generates it from Unicode data files. This should not matter if the module
421        is correctly used as a library, but I received one complaint about 50K of
422        unwanted data. My guess is that the person linked everything into his
423        program rather than using a library. Anyway, it does no harm.
425    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
426        was a minimum greater than 1 for a wide character in a possessive
427        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
428        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
429        character. Chaos in the form of incorrect output or a compiling loop could
430        result.
432    9.  The restrictions on what a pattern can contain when partial matching is
433        requested for pcre_exec() have been removed. All patterns can now be
434        partially matched by this function. In addition, if there are at least two
435        slots in the offset vector, the offset of the earliest inspected character
436        for the match and the offset of the end of the subject are set in them when
437        PCRE_ERROR_PARTIAL is returned.
439    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
440        synonymous with PCRE_PARTIAL, for backwards compatibility, and
441        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
442        and may be more useful for multi-segment matching.
444    11. Partial matching with pcre_exec() is now more intuitive. A partial match
445        used to be given if ever the end of the subject was reached; now it is
446        given only if matching could not proceed because another character was
447        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
448        string "Z", which now yields "no match" instead of "partial match". In the
449        case of pcre_dfa_exec(), "no match" is given if every matching path for the
450        final character ended with (*FAIL).
452    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
453        if the pattern had a "must contain" character that was already found in the
454        earlier partial match, unless partial matching was again requested. For
455        example, with the pattern /dog.(body)?/, the "must contain" character is
456        "g". If the first part-match was for the string "dog", restarting with
457        "sbody" failed. This bug has been fixed.
459    13. The string returned by pcre_dfa_exec() after a partial match has been
460        changed so that it starts at the first inspected character rather than the
461        first character of the match. This makes a difference only if the pattern
462        starts with a lookbehind assertion or \b or \B (\K is not supported by
463        pcre_dfa_exec()). It's an incompatible change, but it makes the two
464        matching functions compatible, and I think it's the right thing to do.
466    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
467        so that the demonstration program is easily available in environments where
468        PCRE has not been installed from source.
470    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
471        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
472        library.
474    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
475        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
476        is not the first non-POSIX option to be added. Clearly some people find
477        these options useful.
479    17. If a caller to the POSIX matching function regexec() passes a non-zero
480        value for nmatch with a NULL value for pmatch, the value of
481        nmatch is forced to zero.
483    18. RunGrepTest did not have a test for the availability of the -u option of
484        the diff command, as RunTest does. It now checks in the same way as
485        RunTest, and also checks for the -b option.
487    19. If an odd number of negated classes containing just a single character
488        interposed, within parentheses, between a forward reference to a named
489        subpattern and the definition of the subpattern, compilation crashed with
490        an internal error, complaining that it could not find the referenced
491        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
492        [The bug was that it was starting one character too far in when skipping
493        over the character class, thus treating the ] as data rather than
494        terminating the class. This meant it could skip too much.]
496    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
497        /g option in pcretest when the pattern contains \K, which makes it possible
498        to have an empty string match not at the start, even when the pattern is
499        anchored. Updated pcretest and pcredemo to use this option.
501    21. If the maximum number of capturing subpatterns in a recursion was greater
502        than the maximum at the outer level, the higher number was returned, but
503        with unset values at the outer level. The correct (outer level) value is
504        now given.
506    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
507        PCRE did not set those parentheses (unlike Perl). I have now found a way to
508        make it do so. The string so far is captured, making this feature
509        compatible with Perl.
511    23. The tests have been re-organized, adding tests 11 and 12, to make it
512        possible to check the Perl 5.10 features against Perl 5.10.
514    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
515        pattern matches a fixed length string. PCRE did not allow this; now it
516        does. Neither allows recursion.
518    25. I finally figured out how to implement a request to provide the minimum
519        length of subject string that was needed in order to match a given pattern.
520        (It was back references and recursion that I had previously got hung up
521        on.) This code has now been added to pcre_study(); it finds a lower bound
522        to the length of subject needed. It is not necessarily the greatest lower
523        bound, but using it to avoid searching strings that are too short does give
524        some useful speed-ups. The value is available to calling programs via
525        pcre_fullinfo().
527    26. While implementing 25, I discovered to my embarrassment that pcretest had
528        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
529        study optimizations had never been tested with that matching function.
530        Oops. What is worse, even when it was passed study data, there was a bug in
531        pcre_dfa_exec() that meant it never actually used it. Double oops. There
532        were also very few tests of studied patterns with pcre_dfa_exec().
534    27. If (?| is used to create subpatterns with duplicate numbers, they are now
535        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
536        on the other side of the coin, they are no longer allowed to have different
537        names, because these cannot be distinguished in PCRE, and this has caused
538        confusion. (This is a difference from Perl.)
540    28. When duplicate subpattern names are present (necessarily with different
541        numbers, as required by 27 above), and a test is made by name in a
542        conditional pattern, either for a subpattern having been matched, or for
543        recursion in such a pattern, all the associated numbered subpatterns are
544        tested, and the overall condition is true if the condition is true for any
545        one of them. This is the way Perl works, and is also more like the way
546        testing by number works.
549    Version 7.9 11-Apr-09
550    ---------------------
552    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
553        (pcretest), all targets were linked against these libraries. This included
554        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
555        libraries. This caused unwanted dependencies to be created. This problem
556        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
557        pcretest is linked with readline.
559    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
560        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
561        moved outside it again, because FALSE and TRUE are already defined in AIX,
562        but BOOL is not.
564    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
565        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
567    4.  The pcregrep documentation said spaces were inserted as well as colons (or
568        hyphens) following file names and line numbers when outputting matching
569        lines. This is not true; no spaces are inserted. I have also clarified the
570        wording for the --colour (or --color) option.
572    5.  In pcregrep, when --colour was used with -o, the list of matching strings
573        was not coloured; this is different to GNU grep, so I have changed it to be
574        the same.
576    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
577        each matching line was coloured. Now it goes on to look for further matches
578        of any of the test patterns, which is the same behaviour as GNU grep.
580    7.  A pattern that could match an empty string could cause pcregrep to loop; it
581        doesn't make sense to accept an empty string match in pcregrep, so I have
582        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
583        seems to be how GNU grep behaves.
585    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
586        start or after a newline", because the conditional assertion was not being
587        correctly handled. The rule now is that both the assertion and what follows
588        in the first alternative must satisfy the test.
590    9.  If auto-callout was enabled in a pattern with a conditional group whose
591        condition was an assertion, PCRE could crash during matching, both with
592        pcre_exec() and pcre_dfa_exec().
594    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
595        used for matching.
597    11. Unicode property support in character classes was not working for
598        characters (bytes) greater than 127 when not in UTF-8 mode.
600    12. Added the -M command line option to pcretest.
602    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
604    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
606    16. Added comments and documentation about mis-use of no_arg in the C++
607        wrapper.
609    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
610        from Martin Jerabek that uses macro names for all relevant character and
611        string constants.
613    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
614        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
615        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
616        these, but not everybody uses configure.
618    19. A conditional group that had only one branch was not being correctly
619        recognized as an item that could match an empty string. This meant that an
620        enclosing group might also not be so recognized, causing infinite looping
621        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
622        with the subject "ab", where knowledge that the repeated group can match
623        nothing is needed in order to break the loop.
625    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
626        exec(), but without supplying a callout function, matching went wrong.
628    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
629        leak if the size of the offset vector was greater than 30. When the vector
630        is smaller, the saved offsets during recursion go onto a local stack
631        vector, but for larger vectors malloc() is used. It was failing to free
632        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
633        error, in fact).
635    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
636        heapframe that is used only when UTF-8 support is enabled. This caused no
637        problem, but was untidy.
639    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
640        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
641        included within another project.
643    24. Steven Van Ingelgem's patches to add more options to the CMake support,
644        slightly modified by me:
646          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
647              not building pcregrep.
649          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
650              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
652    25. Forward references, both numeric and by name, in patterns that made use of
653        duplicate group numbers, could behave incorrectly or give incorrect errors,
654        because when scanning forward to find the reference group, PCRE was not
655        taking into account the duplicate group numbers. A pattern such as
656        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
658    26. Changed a few more instances of "const unsigned char *" to USPTR, making
659        the feature of a custom pointer more persuasive (as requested by a user).
661    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
662        pcretest.c, inside #ifndefs, because it seems they are sometimes already
663        pre-defined.
665    28. Added support for (*UTF8) at the start of a pattern.
667    29. Arrange for flags added by the "release type" setting in CMake to be shown
668        in the configuration summary.
671    Version 7.8 05-Sep-08
672    ---------------------
674    1.  Replaced UCP searching code with optimized version as implemented for Ad
675        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
676        stage table and inline lookup instead of a function, giving speed ups of 2
677        to 5 times on some simple patterns that I tested. Permission was given to
678        distribute the MultiStage2.py script that generates the tables (it's not in
679        the tarball, but is in the Subversion repository).
681    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
682        scripts.
684    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
685        a group with a zero qualifier. The result of the study could be incorrect,
686        or the function might crash, depending on the pattern.
688    4.  Caseless matching was not working for non-ASCII characters in back
689        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
690        It now works when Unicode Property Support is available.
692    5.  In pcretest, an escape such as \x{de} in the data was always generating
693        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
694        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
695        truncation.
697    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
699    7.  Added two (int) casts to pcregrep when printing the difference of two
700        pointers, in case they are 64-bit values.
702    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
703        test 2 if it fails.
705    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
706        and a #define of that name to empty if it is not externally set. This is to
707        allow users of MSVC to set it if necessary.
709    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
710        the convenience functions in the pcre_get.c source file.
712    11. An option change at the start of a pattern that had top-level alternatives
713        could cause overwriting and/or a crash. This command provoked a crash in
714        some environments:
716          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
718        This potential security problem was recorded as CVE-2008-2371.
720    12. For a pattern where the match had to start at the beginning or immediately
721        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
722        pcre_dfa_exec() could read past the end of the passed subject if there was
723        no match. To help with detecting such bugs (e.g. with valgrind), I modified
724        pcretest so that it places the subject at the end of its malloc-ed buffer.
726    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
727        exec() might read past the end of the data buffer in UTF-8 mode.
729    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
730        the data contained the byte 0x85 as part of a UTF-8 character within its
731        first line. This applied both to normal and DFA matching.
733    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
734        /^[^d]*?$/8 failed to match "abc".
736    16. Added a missing copyright notice to pcrecpp_internal.h.
738    17. Make it more clear in the documentation that values returned from
739        pcre_exec() in ovector are byte offsets, not character counts.
741    18. Tidied a few places to stop certain compilers from issuing warnings.
743    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
744        supplied by Stefan Weber. I made a further small update for 7.8 because
745        there is a change of source arrangements: the pcre_searchfuncs.c module is
746        replaced by pcre_ucd.c.
749    Version 7.7 07-May-08
750    ---------------------
752    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
753        a string to a long long, pretend we don't even have a long long." This is
754        done by checking for the strtoq, strtoll, and _strtoi64 functions.
756    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
757        pre-7.6 versions, which defined a global no_arg variable instead of putting
758        it in the RE class. (See also #8 below.)
760    3.  Remove a line of dead code, identified by coverity and reported by Nuno
761        Lopes.
763    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
765        (1) The include/exclude patterns were being applied to the whole pathnames
766            of files, instead of just to the final components.
768        (2) If there was more than one level of directory, the subdirectories were
769            skipped unless they satisfied the include/exclude conditions. This is
770            inconsistent with GNU grep (and could even be seen as contrary to the
771            pcregrep specification - which I improved to make it absolutely clear).
772            The action now is always to scan all levels of directory, and just
773            apply the include/exclude patterns to regular files.
775    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
776        --exclude_dir in the tests to avoid scanning .svn directories.
778    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
779        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
780        doesn't support NULs in patterns.
782    7.  Added some missing "const"s to declarations of static tables in
783        pcre_compile.c and pcre_dfa_exec.c.
785    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
786        caused by fix #2  above. (Subsequently also a second patch to fix the
787        first patch. And a third patch - this was a messy problem.)
789    9.  Applied Craig's patch to remove the use of push_back().
791    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
792        matching function regexec().
794    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
795        which, however, unlike Perl's \g{...}, are subroutine calls, not back
796        references. PCRE supports relative numbers with this syntax (I don't think
797        Oniguruma does).
799    12. Previously, a group with a zero repeat such as (...){0} was completely
800        omitted from the compiled regex. However, this means that if the group
801        was called as a subroutine from elsewhere in the pattern, things went wrong
802        (an internal error was given). Such groups are now left in the compiled
803        pattern, with a new opcode that causes them to be skipped at execution
804        time.
806    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
807        to the way PCRE behaves:
809        (a) A lone ] character is dis-allowed (Perl treats it as data).
811        (b) A back reference to an unmatched subpattern matches an empty string
812            (Perl fails the current match path).
814        (c) A data ] in a character class must be notated as \] because if the
815            first data character in a class is ], it defines an empty class. (In
816            Perl it is not possible to have an empty class.) The empty class []
817            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
818            The negative empty class [^] matches any one character, independently
819            of the DOTALL setting.
821    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
822        non-existent subpattern following a character class starting with ']' and
823        containing () gave an internal compiling error instead of "reference to
824        non-existent subpattern". Fortunately, when the pattern did exist, the
825        compiled code was correct. (When scanning forwards to check for the
826        existencd of the subpattern, it was treating the data ']' as terminating
827        the class, so got the count wrong. When actually compiling, the reference
828        was subsequently set up correctly.)
830    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
831        it was being rejected as not supported by pcre_dfa_exec(), even though
832        other assertions are supported. I have made pcre_dfa_exec() support
833        (*FAIL).
835    16. The implementation of 13c above involved the invention of a new opcode,
836        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
837        cannot be changed at match time, I realized I could make a small
838        improvement to matching performance by compiling OP_ALLANY instead of
839        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
840        on the OP_ANY path.
842    17. Compiling pcretest on Windows with readline support failed without the
843        following two fixes: (1) Make the unistd.h include conditional on
844        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
846    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
847        ncurses library to be included for pcretest when ReadLine support is
848        requested, but also to allow for it to be overridden. This patch came from
849        Daniel Bergström.
851    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
852        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
853        any errors with the current Unicode tables. Thanks to Peter Kankowski for
854        spotting this.
857    Version 7.6 28-Jan-08
858    ---------------------
860    1.  A character class containing a very large number of characters with
861        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
862        overflow.
864    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
865        HAVE_LONG_LONG is not defined.
867    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
868        bring them up to date and include new features. This patch includes:
870        - Fixed PH's badly added libz and libbz2 support.
871        - Fixed a problem with static linking.
872        - Added pcredemo. [But later removed - see 7 below.]
873        - Fixed dftables problem and added an option.
874        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
875            HAVE_LONG_LONG.
876        - Added readline support for pcretest.
877        - Added an listing of the option settings after cmake has run.
879    4.  A user submitted a patch to Makefile that makes it easy to create
880        "pcre.dll" under mingw when using Configure/Make. I added stuff to
881        Makefile.am that cause it to include this special target, without
882        affecting anything else. Note that the same mingw target plus all
883        the other distribution libraries and programs are now supported
884        when configuring with CMake (see 6 below) instead of with
885        Configure/Make.
887    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
888        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
889        exported in the Windows port". It has not yet been confirmed that the patch
890        solves the problem, but it does no harm.
892    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
893        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
894        with CMake, and also correct the comment about stack recursion.
896    7.  Remove the automatic building of pcredemo from the ./configure system and
897        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
898        of a program that users should build themselves after PCRE is installed, so
899        building it automatically is not really right. What is more, it gave
900        trouble in some build environments.
902    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
905    Version 7.5 10-Jan-08
906  ---------------------  ---------------------
908  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'  1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
909      values in parens when parsing an RE using the C++ wrapper."      values in parens when parsing an RE using the C++ wrapper."
911  2.  Negative specials like \S did not work in character classes in UTF-8 mode.  2.  Negative specials like \S did not work in character classes in UTF-8 mode.
912      Characters greater than 255 were excluded from the class instead of being      Characters greater than 255 were excluded from the class instead of being
913      included.      included.
915  3.  The same bug as (2) above applied to negated POSIX classes such as  3.  The same bug as (2) above applied to negated POSIX classes such as
916      [:^space:].      [:^space:].
918  4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it  4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
919      defined or documented. It seems to have been a typo for PCRE_STATIC, so      defined or documented. It seems to have been a typo for PCRE_STATIC, so
920      I have changed it.      I have changed it.
922  5.  The construct (?&) was not diagnosed as a syntax error (it referenced the  5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
923      first named subpattern) and a construct such as (?&a) would reference the      first named subpattern) and a construct such as (?&a) would reference the
924      first named subpattern whose name started with "a" (in other words, the      first named subpattern whose name started with "a" (in other words, the
925      length check was missing).      length check was missing). Both these problems are fixed. "Subpattern name
926        expected" is now given for (?&) (a zero-length name), and this patch also
927        makes it give the same error for \k'' (previously it complained that that
928        was a reference to a non-existent subpattern).
930  6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;  6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
931      this is right because (?- can be followed by option settings as well as by      this is right because (?- can be followed by option settings as well as by
932      digits. I have, however, made the messages clearer.      digits. I have, however, made the messages clearer.
934    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
935        than the number used in the conditional) now cause a compile-time error.
936        This is actually not compatible with Perl, which accepts such patterns, but
937        treats the conditional as always being FALSE (as PCRE used to), but it
938        seems to me that giving a diagnostic is better.
940    8.  Change "alphameric" to the more common word "alphanumeric" in comments
941        and messages.
943    9.  Fix two occurrences of "backslash" in comments that should have been
944        "backspace".
946    10. Remove two redundant lines of code that can never be obeyed (their function
947        was moved elsewhere).
949    11. The program that makes PCRE's Unicode character property table had a bug
950        which caused it to generate incorrect table entries for sequences of
951        characters that have the same character type, but are in different scripts.
952        It amalgamated them into a single range, with the script of the first of
953        them. In other words, some characters were in the wrong script. There were
954        thirteen such cases, affecting characters in the following ranges:
956          U+002b0 - U+002c1
957          U+0060c - U+0060d
958          U+0061e - U+00612
959          U+0064b - U+0065e
960          U+0074d - U+0076d
961          U+01800 - U+01805
962          U+01d00 - U+01d77
963          U+01d9b - U+01dbf
964          U+0200b - U+0200f
965          U+030fc - U+030fe
966          U+03260 - U+0327f
967          U+0fb46 - U+0fbb1
968          U+10450 - U+1049d
970    12. The -o option (show only the matching part of a line) for pcregrep was not
971        compatible with GNU grep in that, if there was more than one match in a
972        line, it showed only the first of them. It now behaves in the same way as
973        GNU grep.
975    13. If the -o and -v options were combined for pcregrep, it printed a blank
976        line for every non-matching line. GNU grep prints nothing, and pcregrep now
977        does the same. The return code can be used to tell if there were any
978        non-matching lines.
980    14. Added --file-offsets and --line-offsets to pcregrep.
982    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
983        infinitely looping recursion. The bug was that positive lookaheads were not
984        being skipped when checking for a possible empty match (negative lookaheads
985        and both kinds of lookbehind were skipped).
987    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
988        inclusion of <windows.h> to before rather than after the definition of
989        INVALID_FILE_ATTRIBUTES (patch from David Byron).
991    17. Specifying a possessive quantifier with a specific limit for a Unicode
992        character property caused pcre_compile() to compile bad code, which led at
993        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
994        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
995        caused the error; without that there was no problem.
997    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
999    19. Added --enable-pcretest-libreadline.
1001    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1002        RE::GlobalReplace(). As a result, the number of replacements returned was
1003        double what it should be. I removed one of the increments, but Craig sent a
1004        later patch that removed the other one (the right fix) and added unit tests
1005        that check the return values (which was not done before).
1007    21. Several CMake things:
1009        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1010            the names libpcre and libpcreposix, not just pcre and pcreposix.
1012        (2) The above change means that pcretest and pcregrep are now correctly
1013            linked with the newly-built libraries, not previously installed ones.
1017    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1018        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1019        UTF-8 newline character). The key issue is that the pattern starts .*;
1020        this means that the match must be either at the beginning, or after a
1021        newline. The bug was in the code for advancing after a failed match and
1022        checking that the new position followed a newline. It was not taking
1023        account of UTF-8 characters correctly.
1025    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1026        character classes. PCRE was not treating the sequence [:...:] as a
1027        character class unless the ... were all letters. Perl, however, seems to
1028        allow any characters between [: and :], though of course it rejects as
1029        unknown any "names" that contain non-letters, because all the known class
1030        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1031        for example, whereas PCRE did not - it did not recognize a POSIX character
1032        class. This seemed a bit dangerous, so the code has been changed to be
1033        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1034        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1035        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1036        Perl does, and where it didn't before.
1038    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1039        Windows environments %n is disabled by default.
1042  Version 7.4 21-Sep-07  Version 7.4 21-Sep-07
1043  ---------------------  ---------------------

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