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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  Version 8.11 10-Oct-2010
5    ------------------------
6    
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".
13    
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).
19    
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.)
24    
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").
32    
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.]
42    
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().
50    
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.
55    
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.
59    
60    9.  Added --match-limit and --recursion-limit to pcregrep.
61    
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
63    
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.
66    
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
69    
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:
73    
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).
77    
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.)
82    
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.
85    
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.
91    
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.
95    
96    
97    Version 8.10 25-Jun-2010
98    ------------------------
99    
100    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
101        THEN.
102    
103    2.  (*ACCEPT) was not working when inside an atomic group.
104    
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.
108    
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.
112    
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.)
115    
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.
121    
122    7.  Minor change to pcretest.c to avoid a compiler warning.
123    
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).
127    
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.
132    
133    10. Added --line-buffered to pcregrep.
134    
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).
140    
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).
146    
147    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
148        possible starting bytes for non-anchored patterns.
149    
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.
153    
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.)
158    
159    16. Added a lot of (int) casts to avoid compiler warnings in systems where
160        size_t is 64-bit (#991).
161    
162    17. Added a check for running out of memory when PCRE is compiled with
163        --disable-stack-for-recursion (#990).
164    
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.
167    
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.)
181    
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.
185    
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.
190    
191    
192    Version 8.02 19-Mar-2010
193    ------------------------
194    
195    1.  The Unicode data tables have been updated to Unicode 5.2.0.
196    
197    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
198        configured.
199    
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.
202    
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.
205    
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".
210    
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.
215    
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).
220    
221    8.  Following on from 7, I added a similar kludge to check the length of the
222        eint vector in pcreposix.c.
223    
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.
229    
230    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
231    
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.
236    
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.
242    
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.
248    
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.
253    
254    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
255    
256    
257    Version 8.01 19-Jan-2010
258    ------------------------
259    
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.
264    
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.)
271    
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.
277    
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
281        PCRE_ERROR_DFA_UITEM.
282    
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.
286    
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.)
289    
290    7.  Some cosmetic changes to the code to make life easier when compiling it
291        as part of something else:
292    
293        (a) Change DEBUG to PCRE_DEBUG.
294    
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.
298    
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.
302    
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.
309    
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).
312    
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:
315    
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.
323    
324    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
325        messages were output:
326    
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.
330    
331        I have done both of these things.
332    
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.
337    
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.
344    
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.
348    
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.
358    
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).
362    
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!"
368    
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.
383    
384    
385    Version 8.00 19-Oct-09
386    ----------------------
387    
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.
392    
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.
396    
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.
404    
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.
409    
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.
414    
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.
417    
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.
424    
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.
431    
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.
438    
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.
443    
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).
451    
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.
458    
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.
465    
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.
469    
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.
473    
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.
478    
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.
482    
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.
486    
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.]
495    
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.
500    
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.
505    
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.
510    
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.
513    
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.
517    
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().
526    
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().
533    
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.)
539    
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.
547    
548    
549    Version 7.9 11-Apr-09
550  ---------------------  ---------------------
551    
552  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
553      (pcretest), all targets were linked against these libraries. This included      (pcretest), all targets were linked against these libraries. This included
554      libpcre, libpcreposix, and libpcrecpp, even though they do not use these      libpcre, libpcreposix, and libpcrecpp, even though they do not use these
555      libraries. This caused unwanted dependencies to be created. This problem      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      has been fixed, and now only pcregrep is linked with bzlib/zlib and only
557      pcretest is linked with readline.      pcretest is linked with readline.
558    
559  2.  The "typedef int BOOL" in pcre_internal.h that was included inside the  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      "#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,      moved outside it again, because FALSE and TRUE are already defined in AIX,
562      but BOOL is not.      but BOOL is not.
563    
564  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
565      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
566    
567  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
568      hyphens) following file names and line numbers when outputting matching      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      lines. This is not true; no spaces are inserted. I have also clarified the
570      wording for the --colour (or --color) option.      wording for the --colour (or --color) option.
571    
572  5.  In pcregrep, when --colour was used with -o, the list of matching strings  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      was not coloured; this is different to GNU grep, so I have changed it to be
574      the same.      the same.
575    
576  6.  When --colo(u)r was used in pcregrep, only the first matching substring in  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      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.      of any of the test patterns, which is the same behaviour as GNU grep.
579    
580  7.  A pattern that could match an empty string could cause pcregrep to loop; it  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      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      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
583      seems to be how GNU grep behaves.      seems to be how GNU grep behaves.
584    
585  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  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      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      correctly handled. The rule now is that both the assertion and what follows
588      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
589    
590  9.  If auto-callout was enabled in a pattern with a conditional group, PCRE  9.  If auto-callout was enabled in a pattern with a conditional group whose
591      could crash during matching.      condition was an assertion, PCRE could crash during matching, both with
592        pcre_exec() and pcre_dfa_exec().
593  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was  
594      used for matching.  10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
595        used for matching.
596  11. Unicode property support in character classes was not working for  
597    11. Unicode property support in character classes was not working for
598      characters (bytes) greater than 127 when not in UTF-8 mode.      characters (bytes) greater than 127 when not in UTF-8 mode.
599    
600  12. Added the -M command line option to pcretest.  12. Added the -M command line option to pcretest.
601    
602  14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.  14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
603    
604    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
605    
606    16. Added comments and documentation about mis-use of no_arg in the C++
607        wrapper.
608    
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.
612    
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.
617    
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.
624    
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.
627    
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).
634    
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.
638    
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.
642    
643    24. Steven Van Ingelgem's patches to add more options to the CMake support,
644        slightly modified by me:
645    
646          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
647              not building pcregrep.
648    
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.
651    
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.
657    
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).
660    
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.
664    
665    28. Added support for (*UTF8) at the start of a pattern.
666    
667    29. Arrange for flags added by the "release type" setting in CMake to be shown
668        in the configuration summary.
669    
670    
671  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
672  ---------------------  ---------------------

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