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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    17. Nobody had reported that the --include_dir option, which was added in
100        release 7.7 should have been called --include-dir (hyphen, not underscore)
101        for compatibility with GNU grep. I have changed it to --include-dir, but
102        left --include_dir as an undocumented synonym, and the same for
103        --exclude-dir, though that is not available in GNU grep, at least as of
104        release 2.5.4.
105    
106    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
107        characters from a string of bytes) have been redefined so as not to use
108        loops, in order to improve performance in some environments. At the same
109        time, I abstracted some of the common code into auxiliary macros to save
110        repetition (this should not affect the compiled code).
111    
112    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
113        compile-time error is now given if \c is not followed by an ASCII
114        character, that is, a byte less than 128. (In EBCDIC mode, the code is
115        different, and any byte value is allowed.)
116    
117    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
118        START_OPTIMIZE option, which is now allowed at compile time - but just
119        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
120        to pcregrep and other applications that have no direct access to PCRE
121        options. The new /Y option in pcretest sets this option when calling
122        pcre_compile().
123    
124    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
125        back references. Groups containing recursive back references were forced to
126        be atomic by that change, but in the case of named groups, the amount of
127        memory required was incorrectly computed, leading to "Failed: internal
128        error: code overflow". This has been fixed.
129    
130    
131    Version 8.10 25-Jun-2010
132    ------------------------
133    
134    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
135        THEN.
136    
137    2.  (*ACCEPT) was not working when inside an atomic group.
138    
139    3.  Inside a character class, \B is treated as a literal by default, but
140        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
141        causes the error). The code is unchanged, but I tidied the documentation.
142    
143    4.  Inside a character class, PCRE always treated \R and \X as literals,
144        whereas Perl faults them if its -w option is set. I have changed PCRE so
145        that it faults them when PCRE_EXTRA is set.
146    
147    5.  Added support for \N, which always matches any character other than
148        newline. (It is the same as "." when PCRE_DOTALL is not set.)
149    
150    6.  When compiling pcregrep with newer versions of gcc which may have
151        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
152        declared with attribute warn_unused_result" were given. Just casting the
153        result to (void) does not stop the warnings; a more elaborate fudge is
154        needed. I've used a macro to implement this.
155    
156    7.  Minor change to pcretest.c to avoid a compiler warning.
157    
158    8.  Added four artifical Unicode properties to help with an option to make
159        \s etc use properties (see next item). The new properties are: Xan
160        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
161    
162    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
163        use Unicode properties. (*UCP) at the start of a pattern can be used to set
164        this option. Modified pcretest to add /W to test this facility. Added
165        REG_UCP to make it available via the POSIX interface.
166    
167    10. Added --line-buffered to pcregrep.
168    
169    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
170        studied, and the match started with a letter with a code point greater than
171        127 whose first byte was different to the first byte of the other case of
172        the letter, the other case of this starting letter was not recognized
173        (#976).
174    
175    12. If a pattern that was studied started with a repeated Unicode property
176        test, for example, \p{Nd}+, there was the theoretical possibility of
177        setting up an incorrect bitmap of starting bytes, but fortunately it could
178        not have actually happened in practice until change 8 above was made (it
179        added property types that matched character-matching opcodes).
180    
181    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
182        possible starting bytes for non-anchored patterns.
183    
184    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
185        \R, and also a number of cases that involve Unicode properties, both
186        explicit and implicit when PCRE_UCP is set.
187    
188    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
189        input, it could crash or give wrong results if characters with values
190        greater than 0xc0 were present in the subject string. (Detail: it assumed
191        UTF-8 input when processing these items.)
192    
193    16. Added a lot of (int) casts to avoid compiler warnings in systems where
194        size_t is 64-bit (#991).
195    
196    17. Added a check for running out of memory when PCRE is compiled with
197        --disable-stack-for-recursion (#990).
198    
199    18. If the last data line in a file for pcretest does not have a newline on
200        the end, a newline was missing in the output.
201    
202    19. The default pcre_chartables.c file recognizes only ASCII characters (values
203        less than 128) in its various bitmaps. However, there is a facility for
204        generating tables according to the current locale when PCRE is compiled. It
205        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
206        characters, are recognized by isspace() and therefore were getting set in
207        these tables, and indeed these tables seem to approximate to ISO 8859. This
208        caused a problem in UTF-8 mode when pcre_study() was used to create a list
209        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
210        which of course cannot start UTF-8 characters. I have changed the code so
211        that only real ASCII characters (less than 128) and the correct starting
212        bytes for UTF-8 encodings are set for characters greater than 127 when in
213        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
214        altogether.)
215    
216    20. Added the /T option to pcretest so as to be able to run tests with non-
217        standard character tables, thus making it possible to include the tests
218        used for 19 above in the standard set of tests.
219    
220    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
221        reference to a subpattern the other side of a comment that contains an
222        opening parenthesis caused either an internal compiling error, or a
223        reference to the wrong subpattern.
224    
225    
226    Version 8.02 19-Mar-2010
227    ------------------------
228    
229    1.  The Unicode data tables have been updated to Unicode 5.2.0.
230    
231    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
232        configured.
233    
234    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
235        original author of that file, following a query about its status.
236    
237    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
238        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
239    
240    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
241        quantifier applied to a forward-referencing subroutine call, could compile
242        incorrect code or give the error "internal error: previously-checked
243        referenced subpattern not found".
244    
245    6.  Both MS Visual Studio and Symbian OS have problems with initializing
246        variables to point to external functions. For these systems, therefore,
247        pcre_malloc etc. are now initialized to local functions that call the
248        relevant global functions.
249    
250    7.  There were two entries missing in the vectors called coptable and poptable
251        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
252        I've fixed the data, and added a kludgy way of testing at compile time that
253        the lengths are correct (equal to the number of opcodes).
254    
255    8.  Following on from 7, I added a similar kludge to check the length of the
256        eint vector in pcreposix.c.
257    
258    9.  Error texts for pcre_compile() are held as one long string to avoid too
259        much relocation at load time. To find a text, the string is searched,
260        counting zeros. There was no check for running off the end of the string,
261        which could happen if a new error number was added without updating the
262        string.
263    
264    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
265    
266    11. \K was not working if it appeared in an atomic group or in a group that
267        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
268        \K is "not well defined" if used in an assertion. PCRE now accepts it if
269        the assertion is positive, but not if it is negative.
270    
271    12. Change 11 fortuitously reduced the size of the stack frame used in the
272        "match()" function of pcre_exec.c by one pointer. Forthcoming
273        implementation of support for (*MARK) will need an extra pointer on the
274        stack; I have reserved it now, so that the stack frame size does not
275        decrease.
276    
277    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
278        item in branch that calls a recursion is a subroutine call - as in the
279        second branch in the above example - was incorrectly given the compile-
280        time error "recursive call could loop indefinitely" because pcre_compile()
281        was not correctly checking the subroutine for matching a non-empty string.
282    
283    14. The checks for overrunning compiling workspace could trigger after an
284        overrun had occurred. This is a "should never occur" error, but it can be
285        triggered by pathological patterns such as hundreds of nested parentheses.
286        The checks now trigger 100 bytes before the end of the workspace.
287    
288    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
289    
290    
291    Version 8.01 19-Jan-2010
292    ------------------------
293    
294    1.  If a pattern contained a conditional subpattern with only one branch (in
295        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
296        computed the wrong minimum data length (which is of course zero for such
297        subpatterns). This could cause incorrect "no match" results.
298    
299    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
300        the pattern is reset in the first branch, pcre_compile() failed with
301        "internal error: code overflow at offset...". This happened only when
302        the reset was to the original external option setting. (An optimization
303        abstracts leading options settings into an external setting, which was the
304        cause of this.)
305    
306    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
307        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
308        assertion pattern did not match (meaning that the assertion was true), it
309        was incorrectly treated as false if the SKIP had been reached during the
310        matching. This also applied to assertions used as conditions.
311    
312    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
313        assertion subpattern, including such a pattern used as a condition,
314        unpredictable results occurred, instead of the error return
315        PCRE_ERROR_DFA_UITEM.
316    
317    5.  The C++ GlobalReplace function was not working like Perl for the special
318        situation when an empty string is matched. It now does the fancy magic
319        stuff that is necessary.
320    
321    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
322        removed. (These were left over from very, very early versions of PCRE.)
323    
324    7.  Some cosmetic changes to the code to make life easier when compiling it
325        as part of something else:
326    
327        (a) Change DEBUG to PCRE_DEBUG.
328    
329        (b) In pcre_compile(), rename the member of the "branch_chain" structure
330            called "current" as "current_branch", to prevent a collision with the
331            Linux macro when compiled as a kernel module.
332    
333        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
334            prevent a collision with the Linux macro when compiled as a kernel
335            module.
336    
337    8.  In pcre_compile() there are some checks for integer overflows that used to
338        cast potentially large values to (double). This has been changed to that
339        when building, a check for int64_t is made, and if it is found, it is used
340        instead, thus avoiding the use of floating point arithmetic. (There is no
341        other use of FP in PCRE.) If int64_t is not found, the fallback is to
342        double.
343    
344    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
345        2005 (difference between two addresses compared to an unsigned value).
346    
347    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
348        custom one, because of the following reported problem in Windows:
349    
350          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
351              under Win32.
352          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
353              therefore missing the function definition.
354          - The compiler thus generates a "C" signature for the test function.
355          - The linker fails to find the "C" function.
356          - PCRE fails to configure if asked to do so against libbz2.
357    
358    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
359        messages were output:
360    
361          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
362          rerunning libtoolize, to keep the correct libtool macros in-tree.
363          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
364    
365        I have done both of these things.
366    
367    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
368        most of the time, it *can* run out if it is given a pattern that contains a
369        runaway infinite recursion. I updated the discussion in the pcrestack man
370        page.
371    
372    13. Now that we have gone to the x.xx style of version numbers, the minor
373        version may start with zero. Using 08 or 09 is a bad idea because users
374        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
375        interpreted as invalid octal numbers. I've updated the previous comment in
376        configure.ac, and also added a check that gives an error if 08 or 09 are
377        used.
378    
379    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
380        causing partial matching to fail when the end of the subject matched \W
381        in a UTF-8 pattern where \W was quantified with a minimum of 3.
382    
383    15. There were some discrepancies between the declarations in pcre_internal.h
384        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
385        their definitions. The declarations used "const uschar *" and the
386        definitions used USPTR. Even though USPTR is normally defined as "const
387        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
388        reported that: "This difference in casting confuses some C++ compilers, for
389        example, SunCC recognizes above declarations as different functions and
390        generates broken code for hbpcre." I have changed the declarations to use
391        USPTR.
392    
393    16. GNU libtool is named differently on some systems. The autogen.sh script now
394        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
395        (FreeBSD).
396    
397    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
398        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
399        comment: "Figure out how to create a longlong from a string: strtoll and
400        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
401        instance, but it only takes 2 args instead of 3!"
402    
403    18. A subtle bug concerned with back references has been fixed by a change of
404        specification, with a corresponding code fix. A pattern such as
405        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
406        refers, was giving matches when it shouldn't. For example, xa=xaaa would
407        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
408        same bug. Such groups have to be quantified to be useful, or contained
409        inside another quantified group. (If there's no repetition, the reference
410        can never match.) The problem arises because, having left the group and
411        moved on to the rest of the pattern, a later failure that backtracks into
412        the group uses the captured value from the final iteration of the group
413        rather than the correct earlier one. I have fixed this in PCRE by forcing
414        any group that contains a reference to itself to be an atomic group; that
415        is, there cannot be any backtracking into it once it has completed. This is
416        similar to recursive and subroutine calls.
417    
418    
419    Version 8.00 19-Oct-09
420  ----------------------  ----------------------
421    
422  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
423      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
424      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
425      error.      error.
426    
427  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,
428      "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
429      in a Windows environment.      in a Windows environment.
430    
431  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
432      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
433      --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
434      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
435      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
436      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
437      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
438    
439  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
440      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
441      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
442      the old behaviour.      the old behaviour.
443    
444  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
445      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
446      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
447      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
448    
449  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
450      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
451    
452  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
453      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
454      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
455      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
456      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
457      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
458    
459  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
460      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
461      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
462      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
463      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
464      result.      result.
465    
466  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
467      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
468      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
469      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
470      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
471      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
472    
473  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
474      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
475      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,
476      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
477      pcre_exec().  
478    11. Partial matching with pcre_exec() is now more intuitive. A partial match
479  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
480      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
481      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
482      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
483      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
484      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
485      final character ended with (*FAIL).  
   
486  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
487      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
488      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
489      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
490      "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
491      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
492    
493  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
494      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
495      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
496      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
497      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
498      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.
499    
500  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,
501      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
502      PCRE has not been installed from source.      PCRE has not been installed from source.
503    
504  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,
505      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
506      library.      library.
507    
508  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.
509      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
510      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
511      these options useful.      these options useful.
512    
513  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
514      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
515      nmatch is forced to zero.      nmatch is forced to zero.
516    
517  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
518      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
519      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
520    
521  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
522      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
523      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
524      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
525      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
526      [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
527      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
528      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
529    
530  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
531      /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
532      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
533      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
534    
535  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
536      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
537      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
538      now given.      now given.
539    
540  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
541      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
542      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
543      compatible with Perl.      compatible with Perl.
544    
545    23. The tests have been re-organized, adding tests 11 and 12, to make it
546        possible to check the Perl 5.10 features against Perl 5.10.
547    
548    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
549        pattern matches a fixed length string. PCRE did not allow this; now it
550        does. Neither allows recursion.
551    
552    25. I finally figured out how to implement a request to provide the minimum
553        length of subject string that was needed in order to match a given pattern.
554        (It was back references and recursion that I had previously got hung up
555        on.) This code has now been added to pcre_study(); it finds a lower bound
556        to the length of subject needed. It is not necessarily the greatest lower
557        bound, but using it to avoid searching strings that are too short does give
558        some useful speed-ups. The value is available to calling programs via
559        pcre_fullinfo().
560    
561    26. While implementing 25, I discovered to my embarrassment that pcretest had
562        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
563        study optimizations had never been tested with that matching function.
564        Oops. What is worse, even when it was passed study data, there was a bug in
565        pcre_dfa_exec() that meant it never actually used it. Double oops. There
566        were also very few tests of studied patterns with pcre_dfa_exec().
567    
568    27. If (?| is used to create subpatterns with duplicate numbers, they are now
569        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
570        on the other side of the coin, they are no longer allowed to have different
571        names, because these cannot be distinguished in PCRE, and this has caused
572        confusion. (This is a difference from Perl.)
573    
574    28. When duplicate subpattern names are present (necessarily with different
575        numbers, as required by 27 above), and a test is made by name in a
576        conditional pattern, either for a subpattern having been matched, or for
577        recursion in such a pattern, all the associated numbered subpatterns are
578        tested, and the overall condition is true if the condition is true for any
579        one of them. This is the way Perl works, and is also more like the way
580        testing by number works.
581    
582    
583  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
584  ---------------------  ---------------------

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