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revision 497 by ph10, Wed Mar 3 12:01:00 2010 UTC revision 569 by ph10, Sun Nov 7 16:14:50 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    
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.  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  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
201      configured.      configured.
202    
203  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
204      original author of that file, following a query about its status.      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  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.      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  5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
210      quantifier applied to a forward-referencing subroutine call, could compile      quantifier applied to a forward-referencing subroutine call, could compile
211      incorrect code or give the error "internal error: previously-checked      incorrect code or give the error "internal error: previously-checked
212      referenced subpattern not found".      referenced subpattern not found".
213    
214  6.  Both MS Visual Studio and Symbian OS have problems with initializing  6.  Both MS Visual Studio and Symbian OS have problems with initializing
215      variables to point to external functions. For these systems, therefore,      variables to point to external functions. For these systems, therefore,
216      pcre_malloc etc. are now initialized to local functions that call the      pcre_malloc etc. are now initialized to local functions that call the
217      relevant global functions.      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  Version 8.01 19-Jan-2010
261  ------------------------  ------------------------

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