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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  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    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
97        bad UTF-8 sequence and one that is incomplete.
98    
99    
100    Version 8.10 25-Jun-2010
101    ------------------------
102    
103    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
104        THEN.
105    
106    2.  (*ACCEPT) was not working when inside an atomic group.
107    
108    3.  Inside a character class, \B is treated as a literal by default, but
109        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
110        causes the error). The code is unchanged, but I tidied the documentation.
111    
112    4.  Inside a character class, PCRE always treated \R and \X as literals,
113        whereas Perl faults them if its -w option is set. I have changed PCRE so
114        that it faults them when PCRE_EXTRA is set.
115    
116    5.  Added support for \N, which always matches any character other than
117        newline. (It is the same as "." when PCRE_DOTALL is not set.)
118    
119    6.  When compiling pcregrep with newer versions of gcc which may have
120        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
121        declared with attribute warn_unused_result" were given. Just casting the
122        result to (void) does not stop the warnings; a more elaborate fudge is
123        needed. I've used a macro to implement this.
124    
125    7.  Minor change to pcretest.c to avoid a compiler warning.
126    
127    8.  Added four artifical Unicode properties to help with an option to make
128        \s etc use properties (see next item). The new properties are: Xan
129        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
130    
131    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
132        use Unicode properties. (*UCP) at the start of a pattern can be used to set
133        this option. Modified pcretest to add /W to test this facility. Added
134        REG_UCP to make it available via the POSIX interface.
135    
136    10. Added --line-buffered to pcregrep.
137    
138    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
139        studied, and the match started with a letter with a code point greater than
140        127 whose first byte was different to the first byte of the other case of
141        the letter, the other case of this starting letter was not recognized
142        (#976).
143    
144    12. If a pattern that was studied started with a repeated Unicode property
145        test, for example, \p{Nd}+, there was the theoretical possibility of
146        setting up an incorrect bitmap of starting bytes, but fortunately it could
147        not have actually happened in practice until change 8 above was made (it
148        added property types that matched character-matching opcodes).
149    
150    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
151        possible starting bytes for non-anchored patterns.
152    
153    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
154        \R, and also a number of cases that involve Unicode properties, both
155        explicit and implicit when PCRE_UCP is set.
156    
157    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
158        input, it could crash or give wrong results if characters with values
159        greater than 0xc0 were present in the subject string. (Detail: it assumed
160        UTF-8 input when processing these items.)
161    
162    16. Added a lot of (int) casts to avoid compiler warnings in systems where
163        size_t is 64-bit (#991).
164    
165    17. Added a check for running out of memory when PCRE is compiled with
166        --disable-stack-for-recursion (#990).
167    
168    18. If the last data line in a file for pcretest does not have a newline on
169        the end, a newline was missing in the output.
170    
171    19. The default pcre_chartables.c file recognizes only ASCII characters (values
172        less than 128) in its various bitmaps. However, there is a facility for
173        generating tables according to the current locale when PCRE is compiled. It
174        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
175        characters, are recognized by isspace() and therefore were getting set in
176        these tables, and indeed these tables seem to approximate to ISO 8859. This
177        caused a problem in UTF-8 mode when pcre_study() was used to create a list
178        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
179        which of course cannot start UTF-8 characters. I have changed the code so
180        that only real ASCII characters (less than 128) and the correct starting
181        bytes for UTF-8 encodings are set for characters greater than 127 when in
182        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
183        altogether.)
184    
185    20. Added the /T option to pcretest so as to be able to run tests with non-
186        standard character tables, thus making it possible to include the tests
187        used for 19 above in the standard set of tests.
188    
189    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
190        reference to a subpattern the other side of a comment that contains an
191        opening parenthesis caused either an internal compiling error, or a
192        reference to the wrong subpattern.
193    
194    
195    Version 8.02 19-Mar-2010
196    ------------------------
197    
198    1.  The Unicode data tables have been updated to Unicode 5.2.0.
199    
200    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
201        configured.
202    
203    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
204        original author of that file, following a query about its status.
205    
206    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
207        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
208    
209    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
210        quantifier applied to a forward-referencing subroutine call, could compile
211        incorrect code or give the error "internal error: previously-checked
212        referenced subpattern not found".
213    
214    6.  Both MS Visual Studio and Symbian OS have problems with initializing
215        variables to point to external functions. For these systems, therefore,
216        pcre_malloc etc. are now initialized to local functions that call the
217        relevant global functions.
218    
219    7.  There were two entries missing in the vectors called coptable and poptable
220        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
221        I've fixed the data, and added a kludgy way of testing at compile time that
222        the lengths are correct (equal to the number of opcodes).
223    
224    8.  Following on from 7, I added a similar kludge to check the length of the
225        eint vector in pcreposix.c.
226    
227    9.  Error texts for pcre_compile() are held as one long string to avoid too
228        much relocation at load time. To find a text, the string is searched,
229        counting zeros. There was no check for running off the end of the string,
230        which could happen if a new error number was added without updating the
231        string.
232    
233    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
234    
235    11. \K was not working if it appeared in an atomic group or in a group that
236        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
237        \K is "not well defined" if used in an assertion. PCRE now accepts it if
238        the assertion is positive, but not if it is negative.
239    
240    12. Change 11 fortuitously reduced the size of the stack frame used in the
241        "match()" function of pcre_exec.c by one pointer. Forthcoming
242        implementation of support for (*MARK) will need an extra pointer on the
243        stack; I have reserved it now, so that the stack frame size does not
244        decrease.
245    
246    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
247        item in branch that calls a recursion is a subroutine call - as in the
248        second branch in the above example - was incorrectly given the compile-
249        time error "recursive call could loop indefinitely" because pcre_compile()
250        was not correctly checking the subroutine for matching a non-empty string.
251    
252    14. The checks for overrunning compiling workspace could trigger after an
253        overrun had occurred. This is a "should never occur" error, but it can be
254        triggered by pathological patterns such as hundreds of nested parentheses.
255        The checks now trigger 100 bytes before the end of the workspace.
256    
257    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
258    
259    
260    Version 8.01 19-Jan-2010
261    ------------------------
262    
263    1.  If a pattern contained a conditional subpattern with only one branch (in
264        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
265        computed the wrong minimum data length (which is of course zero for such
266        subpatterns). This could cause incorrect "no match" results.
267    
268    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
269        the pattern is reset in the first branch, pcre_compile() failed with
270        "internal error: code overflow at offset...". This happened only when
271        the reset was to the original external option setting. (An optimization
272        abstracts leading options settings into an external setting, which was the
273        cause of this.)
274    
275    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
276        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
277        assertion pattern did not match (meaning that the assertion was true), it
278        was incorrectly treated as false if the SKIP had been reached during the
279        matching. This also applied to assertions used as conditions.
280    
281    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
282        assertion subpattern, including such a pattern used as a condition,
283        unpredictable results occurred, instead of the error return
284        PCRE_ERROR_DFA_UITEM.
285    
286    5.  The C++ GlobalReplace function was not working like Perl for the special
287        situation when an empty string is matched. It now does the fancy magic
288        stuff that is necessary.
289    
290    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
291        removed. (These were left over from very, very early versions of PCRE.)
292    
293    7.  Some cosmetic changes to the code to make life easier when compiling it
294        as part of something else:
295    
296        (a) Change DEBUG to PCRE_DEBUG.
297    
298        (b) In pcre_compile(), rename the member of the "branch_chain" structure
299            called "current" as "current_branch", to prevent a collision with the
300            Linux macro when compiled as a kernel module.
301    
302        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
303            prevent a collision with the Linux macro when compiled as a kernel
304            module.
305    
306    8.  In pcre_compile() there are some checks for integer overflows that used to
307        cast potentially large values to (double). This has been changed to that
308        when building, a check for int64_t is made, and if it is found, it is used
309        instead, thus avoiding the use of floating point arithmetic. (There is no
310        other use of FP in PCRE.) If int64_t is not found, the fallback is to
311        double.
312    
313    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
314        2005 (difference between two addresses compared to an unsigned value).
315    
316    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
317        custom one, because of the following reported problem in Windows:
318    
319          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
320              under Win32.
321          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
322              therefore missing the function definition.
323          - The compiler thus generates a "C" signature for the test function.
324          - The linker fails to find the "C" function.
325          - PCRE fails to configure if asked to do so against libbz2.
326    
327    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
328        messages were output:
329    
330          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
331          rerunning libtoolize, to keep the correct libtool macros in-tree.
332          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
333    
334        I have done both of these things.
335    
336    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
337        most of the time, it *can* run out if it is given a pattern that contains a
338        runaway infinite recursion. I updated the discussion in the pcrestack man
339        page.
340    
341    13. Now that we have gone to the x.xx style of version numbers, the minor
342        version may start with zero. Using 08 or 09 is a bad idea because users
343        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
344        interpreted as invalid octal numbers. I've updated the previous comment in
345        configure.ac, and also added a check that gives an error if 08 or 09 are
346        used.
347    
348    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
349        causing partial matching to fail when the end of the subject matched \W
350        in a UTF-8 pattern where \W was quantified with a minimum of 3.
351    
352    15. There were some discrepancies between the declarations in pcre_internal.h
353        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
354        their definitions. The declarations used "const uschar *" and the
355        definitions used USPTR. Even though USPTR is normally defined as "const
356        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
357        reported that: "This difference in casting confuses some C++ compilers, for
358        example, SunCC recognizes above declarations as different functions and
359        generates broken code for hbpcre." I have changed the declarations to use
360        USPTR.
361    
362    16. GNU libtool is named differently on some systems. The autogen.sh script now
363        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
364        (FreeBSD).
365    
366    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
367        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
368        comment: "Figure out how to create a longlong from a string: strtoll and
369        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
370        instance, but it only takes 2 args instead of 3!"
371    
372    18. A subtle bug concerned with back references has been fixed by a change of
373        specification, with a corresponding code fix. A pattern such as
374        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
375        refers, was giving matches when it shouldn't. For example, xa=xaaa would
376        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
377        same bug. Such groups have to be quantified to be useful, or contained
378        inside another quantified group. (If there's no repetition, the reference
379        can never match.) The problem arises because, having left the group and
380        moved on to the rest of the pattern, a later failure that backtracks into
381        the group uses the captured value from the final iteration of the group
382        rather than the correct earlier one. I have fixed this in PCRE by forcing
383        any group that contains a reference to itself to be an atomic group; that
384        is, there cannot be any backtracking into it once it has completed. This is
385        similar to recursive and subroutine calls.
386    
387    
388    Version 8.00 19-Oct-09
389  ----------------------  ----------------------
390    
391  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
392      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
393      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
394      error.      error.
395    
396  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
397      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
398      in a Windows environment.      in a Windows environment.
399    
400  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
401      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
402      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
403      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
404      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
405      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
406      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
407    
408  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
409      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
410      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
411      the old behaviour.      the old behaviour.
412    
413  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
414      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
415      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
416      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
417    
418  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
419      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
420    
421  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
422      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
423      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
424      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
425      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
426      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
427    
428  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
429      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
430      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
431      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
432      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
433      result.      result.
434    
435  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
436      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
437      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
438      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
439      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
440      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
441    
442  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
443      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
444      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
445      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
446      pcre_exec().  
447    11. Partial matching with pcre_exec() is now more intuitive. A partial match
448  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
449      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
450      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
451      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
452      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
453      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
454      final character ended with (*FAIL).  
   
455  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
456      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
457      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
458      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
459      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
460      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
461    
462  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
463      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
464      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
465      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
466      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
467      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
468    
469  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
470      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
471      PCRE has not been installed from source.      PCRE has not been installed from source.
472    
473  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
474      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
475      library.      library.
476    
477  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
478      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
479      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
480      these options useful.      these options useful.
481    
482  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
483      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
484      nmatch is forced to zero.      nmatch is forced to zero.
485    
486  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
487      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
488      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
489    
490  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
491      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
492      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
493      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
494      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
495      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
496      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
497      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
498    
499  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
500      /g option in pcretest when the pattern contains \K, which makes it possible      /g option in pcretest when the pattern contains \K, which makes it possible
501      to have an empty string match not at the start, even when the pattern is      to have an empty string match not at the start, even when the pattern is
502      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
503    
504  21. If the maximum number of capturing subpatterns in a recursion was greater  21. If the maximum number of capturing subpatterns in a recursion was greater
505      than the maximum at the outer level, the higher number was returned, but      than the maximum at the outer level, the higher number was returned, but
506      with unset values at the outer level. The correct (outer level) value is      with unset values at the outer level. The correct (outer level) value is
507      now given.      now given.
508    
509  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
510      PCRE did not set those parentheses (unlike Perl). I have now found a way to      PCRE did not set those parentheses (unlike Perl). I have now found a way to
511      make it do so. The string so far is captured, making this feature      make it do so. The string so far is captured, making this feature
512      compatible with Perl.      compatible with Perl.
513    
514    23. The tests have been re-organized, adding tests 11 and 12, to make it
515        possible to check the Perl 5.10 features against Perl 5.10.
516    
517    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
518        pattern matches a fixed length string. PCRE did not allow this; now it
519        does. Neither allows recursion.
520    
521    25. I finally figured out how to implement a request to provide the minimum
522        length of subject string that was needed in order to match a given pattern.
523        (It was back references and recursion that I had previously got hung up
524        on.) This code has now been added to pcre_study(); it finds a lower bound
525        to the length of subject needed. It is not necessarily the greatest lower
526        bound, but using it to avoid searching strings that are too short does give
527        some useful speed-ups. The value is available to calling programs via
528        pcre_fullinfo().
529    
530    26. While implementing 25, I discovered to my embarrassment that pcretest had
531        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
532        study optimizations had never been tested with that matching function.
533        Oops. What is worse, even when it was passed study data, there was a bug in
534        pcre_dfa_exec() that meant it never actually used it. Double oops. There
535        were also very few tests of studied patterns with pcre_dfa_exec().
536    
537    27. If (?| is used to create subpatterns with duplicate numbers, they are now
538        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
539        on the other side of the coin, they are no longer allowed to have different
540        names, because these cannot be distinguished in PCRE, and this has caused
541        confusion. (This is a difference from Perl.)
542    
543    28. When duplicate subpattern names are present (necessarily with different
544        numbers, as required by 27 above), and a test is made by name in a
545        conditional pattern, either for a subpattern having been matched, or for
546        recursion in such a pattern, all the associated numbered subpatterns are
547        tested, and the overall condition is true if the condition is true for any
548        one of them. This is the way Perl works, and is also more like the way
549        testing by number works.
550    
551    
552  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
553  ---------------------  ---------------------

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