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revision 496 by ph10, Tue Mar 2 19:11:17 2010 UTC revision 576 by ph10, Sun Nov 21 18:45:10 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  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    
125    Version 8.10 25-Jun-2010
126    ------------------------
127    
128    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
129        THEN.
130    
131    2.  (*ACCEPT) was not working when inside an atomic group.
132    
133    3.  Inside a character class, \B is treated as a literal by default, but
134        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
135        causes the error). The code is unchanged, but I tidied the documentation.
136    
137    4.  Inside a character class, PCRE always treated \R and \X as literals,
138        whereas Perl faults them if its -w option is set. I have changed PCRE so
139        that it faults them when PCRE_EXTRA is set.
140    
141    5.  Added support for \N, which always matches any character other than
142        newline. (It is the same as "." when PCRE_DOTALL is not set.)
143    
144    6.  When compiling pcregrep with newer versions of gcc which may have
145        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
146        declared with attribute warn_unused_result" were given. Just casting the
147        result to (void) does not stop the warnings; a more elaborate fudge is
148        needed. I've used a macro to implement this.
149    
150    7.  Minor change to pcretest.c to avoid a compiler warning.
151    
152    8.  Added four artifical Unicode properties to help with an option to make
153        \s etc use properties (see next item). The new properties are: Xan
154        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
155    
156    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
157        use Unicode properties. (*UCP) at the start of a pattern can be used to set
158        this option. Modified pcretest to add /W to test this facility. Added
159        REG_UCP to make it available via the POSIX interface.
160    
161    10. Added --line-buffered to pcregrep.
162    
163    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
164        studied, and the match started with a letter with a code point greater than
165        127 whose first byte was different to the first byte of the other case of
166        the letter, the other case of this starting letter was not recognized
167        (#976).
168    
169    12. If a pattern that was studied started with a repeated Unicode property
170        test, for example, \p{Nd}+, there was the theoretical possibility of
171        setting up an incorrect bitmap of starting bytes, but fortunately it could
172        not have actually happened in practice until change 8 above was made (it
173        added property types that matched character-matching opcodes).
174    
175    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
176        possible starting bytes for non-anchored patterns.
177    
178    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
179        \R, and also a number of cases that involve Unicode properties, both
180        explicit and implicit when PCRE_UCP is set.
181    
182    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
183        input, it could crash or give wrong results if characters with values
184        greater than 0xc0 were present in the subject string. (Detail: it assumed
185        UTF-8 input when processing these items.)
186    
187    16. Added a lot of (int) casts to avoid compiler warnings in systems where
188        size_t is 64-bit (#991).
189    
190    17. Added a check for running out of memory when PCRE is compiled with
191        --disable-stack-for-recursion (#990).
192    
193    18. If the last data line in a file for pcretest does not have a newline on
194        the end, a newline was missing in the output.
195    
196    19. The default pcre_chartables.c file recognizes only ASCII characters (values
197        less than 128) in its various bitmaps. However, there is a facility for
198        generating tables according to the current locale when PCRE is compiled. It
199        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
200        characters, are recognized by isspace() and therefore were getting set in
201        these tables, and indeed these tables seem to approximate to ISO 8859. This
202        caused a problem in UTF-8 mode when pcre_study() was used to create a list
203        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
204        which of course cannot start UTF-8 characters. I have changed the code so
205        that only real ASCII characters (less than 128) and the correct starting
206        bytes for UTF-8 encodings are set for characters greater than 127 when in
207        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
208        altogether.)
209    
210    20. Added the /T option to pcretest so as to be able to run tests with non-
211        standard character tables, thus making it possible to include the tests
212        used for 19 above in the standard set of tests.
213    
214    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
215        reference to a subpattern the other side of a comment that contains an
216        opening parenthesis caused either an internal compiling error, or a
217        reference to the wrong subpattern.
218    
219    
220    Version 8.02 19-Mar-2010
221  ------------------------  ------------------------
222    
223  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
224    
225  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
226      configured.      configured.
227    
228  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
229      original author of that file, following a query about its status.      original author of that file, following a query about its status.
230    
231  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include  4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
232      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.      inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
233    
234  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
235      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
236      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
237      referenced subpattern not found".      referenced subpattern not found".
238    
239    6.  Both MS Visual Studio and Symbian OS have problems with initializing
240        variables to point to external functions. For these systems, therefore,
241        pcre_malloc etc. are now initialized to local functions that call the
242        relevant global functions.
243    
244    7.  There were two entries missing in the vectors called coptable and poptable
245        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
246        I've fixed the data, and added a kludgy way of testing at compile time that
247        the lengths are correct (equal to the number of opcodes).
248    
249    8.  Following on from 7, I added a similar kludge to check the length of the
250        eint vector in pcreposix.c.
251    
252    9.  Error texts for pcre_compile() are held as one long string to avoid too
253        much relocation at load time. To find a text, the string is searched,
254        counting zeros. There was no check for running off the end of the string,
255        which could happen if a new error number was added without updating the
256        string.
257    
258    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
259    
260    11. \K was not working if it appeared in an atomic group or in a group that
261        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
262        \K is "not well defined" if used in an assertion. PCRE now accepts it if
263        the assertion is positive, but not if it is negative.
264    
265    12. Change 11 fortuitously reduced the size of the stack frame used in the
266        "match()" function of pcre_exec.c by one pointer. Forthcoming
267        implementation of support for (*MARK) will need an extra pointer on the
268        stack; I have reserved it now, so that the stack frame size does not
269        decrease.
270    
271    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
272        item in branch that calls a recursion is a subroutine call - as in the
273        second branch in the above example - was incorrectly given the compile-
274        time error "recursive call could loop indefinitely" because pcre_compile()
275        was not correctly checking the subroutine for matching a non-empty string.
276    
277    14. The checks for overrunning compiling workspace could trigger after an
278        overrun had occurred. This is a "should never occur" error, but it can be
279        triggered by pathological patterns such as hundreds of nested parentheses.
280        The checks now trigger 100 bytes before the end of the workspace.
281    
282    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
283    
284    
285  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
286  ------------------------  ------------------------

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