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revision 153 by ph10, Wed Apr 18 09:12:14 2007 UTC revision 210 by ph10, Wed Aug 8 14:24:50 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 7.3 05-Jul-07
5    ---------------------
6    
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
12    
13          #include "pcre.h"
14    
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
18    
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
26    
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
28    
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
31    
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
34    
35     6. ESC_K was left out of the EBCDIC table.
36    
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
50    
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
55    
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
67    
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
72    
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
79    
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
86    
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
90    
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
93    
94    14. Optimized (?!) to (*FAIL).
95    
96    
97    Version 7.2 19-Jun-07
98    ---------------------
99    
100     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
101        which is apparently normally available under Windows.
102    
103     2. Re-jig the pcregrep tests with different newline settings in an attempt
104        to make them independent of the local environment's newline setting.
105    
106     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
107    
108     4. Some of the "internals" tests were previously cut out when the link size
109        was not 2, because the output contained actual offsets. The recent new
110        "Z" feature of pcretest means that these can be cut out, making the tests
111        usable with all link sizes.
112    
113     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
114        stack recursion. This gives a massive performance boost under BSD, but just
115        a small improvement under Linux. However, it saves one field in the frame
116        in all cases.
117    
118     6. Added more features from the forthcoming Perl 5.10:
119    
120        (a) (?-n) (where n is a string of digits) is a relative subroutine or
121            recursion call. It refers to the nth most recently opened parentheses.
122    
123        (b) (?+n) is also a relative subroutine call; it refers to the nth next
124            to be opened parentheses.
125    
126        (c) Conditions that refer to capturing parentheses can be specified
127            relatively, for example, (?(-2)... or (?(+3)...
128    
129        (d) \K resets the start of the current match so that everything before
130            is not part of it.
131    
132        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
133    
134        (f) \g{name} is another synonym - part of Perl 5.10's unification of
135            reference syntax.
136    
137        (g) (?| introduces a group in which the numbering of parentheses in each
138            alternative starts with the same number.
139    
140        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
141    
142     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
143        PCRE_INFO_JCHANGED.
144    
145     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
146        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
147        for detecting groups that can match an empty string.
148    
149     9. A pattern with a very large number of alternatives (more than several
150        hundred) was running out of internal workspace during the pre-compile
151        phase, where pcre_compile() figures out how much memory will be needed. A
152        bit of new cunning has reduced the workspace needed for groups with
153        alternatives. The 1000-alternative test pattern now uses 12 bytes of
154        workspace instead of running out of the 4096 that are available.
155    
156    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
157    
158    11. Applied patch from Google to remove an optimization that didn't quite work.
159        The report of the bug said:
160    
161          pcrecpp::RE("a*").FullMatch("aaa") matches, while
162          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
163          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
164    
165    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
166        it matched the wrong number of bytes.
167    
168    
169    Version 7.1 24-Apr-07
170  ---------------------  ---------------------
171    
172   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one

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