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revision 184 by ph10, Tue Jun 19 13:26:46 2007 UTC revision 230 by ph10, Mon Sep 10 13:23:56 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 19-June-07  Version 7.4 10-Sep-07
5    ---------------------
6    
7    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8        means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
13    
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
19    
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
25    
26    
27    Version 7.3 28-Aug-07
28    ---------------------
29    
30     1. In the rejigging of the build system that eventually resulted in 7.1, the
31        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
32        brackets there is not right, since it causes compilers to look for an
33        installed pcre.h, not the version that is in the source that is being
34        compiled (which of course may be different). I have changed it back to:
35    
36          #include "pcre.h"
37    
38        I have a vague recollection that the change was concerned with compiling in
39        different directories, but in the new build system, that is taken care of
40        by the VPATH setting the Makefile.
41    
42     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
43        when the subject happened to end in the byte 0x85 (e.g. if the last
44        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
45        characters but of course it shouldn't be taken as a newline when it is part
46        of another character. The bug was that, for an unlimited repeat of . in
47        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
48        characters when looking for a newline.
49    
50     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
51    
52     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
53        in debug output.
54    
55     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
56        long printing in the pcrecpp unittest when running under MinGW.
57    
58     6. ESC_K was left out of the EBCDIC table.
59    
60     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
61        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
62        limit also applies to "virtual nesting" when a pattern is recursive, and in
63        this case 1000 isn't so big. I have been able to remove this limit at the
64        expense of backing off one optimization in certain circumstances. Normally,
65        when pcre_exec() would call its internal match() function recursively and
66        immediately return the result unconditionally, it uses a "tail recursion"
67        feature to save stack. However, when a subpattern that can match an empty
68        string has an unlimited repetition quantifier, it no longer makes this
69        optimization. That gives it a stack frame in which to save the data for
70        checking that an empty string has been matched. Previously this was taken
71        from the 1000-entry workspace that had been reserved. So now there is no
72        explicit limit, but more stack is used.
73    
74     8. Applied Daniel's patches to solve problems with the import/export magic
75        syntax that is required for Windows, and which was going wrong for the
76        pcreposix and pcrecpp parts of the library. These were overlooked when this
77        problem was solved for the main library.
78    
79     9. There were some crude static tests to avoid integer overflow when computing
80        the size of patterns that contain repeated groups with explicit upper
81        limits. As the maximum quantifier is 65535, the maximum group length was
82        set at 30,000 so that the product of these two numbers did not overflow a
83        32-bit integer. However, it turns out that people want to use groups that
84        are longer than 30,000 bytes (though not repeat them that many times).
85        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
86        made it possible to implement the integer overflow checks in a much more
87        dynamic way, which I have now done. The artificial limitation on group
88        length has been removed - we now have only the limit on the total length of
89        the compiled pattern, which depends on the LINK_SIZE setting.
90    
91    10. Fixed a bug in the documentation for get/copy named substring when
92        duplicate names are permitted. If none of the named substrings are set, the
93        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
94        empty string.
95    
96    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
97        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
98        because the ] is interpreted as the first data character and the
99        terminating ] is not found. PCRE has been made compatible with Perl in this
100        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
101        cause memory overwriting.
102    
103    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
104        string has been matched (to stop an infinite loop). It was not recognizing
105        a conditional subpattern that could match an empty string if that
106        subpattern was within another subpattern. For example, it looped when
107        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
108        condition was not nested. This bug has been fixed.
109    
110    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
111        past the start of the subject in the presence of bytes with the top bit
112        set, for example "\x8aBCD".
113    
114    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
115        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
116    
117    14. Optimized (?!) to (*FAIL).
118    
119    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
120        This restricts code points to be within the range 0 to 0x10FFFF, excluding
121        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
122        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
123        does: it's just the validity check that is more restrictive.
124    
125    16. Inserted checks for integer overflows during escape sequence (backslash)
126        processing, and also fixed erroneous offset values for syntax errors during
127        backslash processing.
128    
129    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
130        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
131    
132    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
133        caused an overrun.
134    
135    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
136        something other than just ASCII characters) inside a group that had an
137        unlimited repeat caused a loop at compile time (while checking to see
138        whether the group could match an empty string).
139    
140    20. Debugging a pattern containing \p or \P could cause a crash. For example,
141        [\P{Any}] did so. (Error in the code for printing property names.)
142    
143    21. An orphan \E inside a character class could cause a crash.
144    
145    22. A repeated capturing bracket such as (A)? could cause a wild memory
146        reference during compilation.
147    
148    23. There are several functions in pcre_compile() that scan along a compiled
149        expression for various reasons (e.g. to see if it's fixed length for look
150        behind). There were bugs in these functions when a repeated \p or \P was
151        present in the pattern. These operators have additional parameters compared
152        with \d, etc, and these were not being taken into account when moving along
153        the compiled data. Specifically:
154    
155        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
156            length.
157    
158        (b) An item such as \pL+ within a repeated group could cause crashes or
159            loops.
160    
161        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
162            "reference to non-existent subpattern" error.
163    
164        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
165    
166    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
167        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
168    
169    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
170    
171    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
172        character were causing crashes (broken optimization).
173    
174    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
175        \p or \P) caused a compile-time loop.
176    
177    28. More problems have arisen in unanchored patterns when CRLF is a valid line
178        break. For example, the unstudied pattern [\r\n]A does not match the string
179        "\r\nA" because change 7.0/46 below moves the current point on by two
180        characters after failing to match at the start. However, the pattern \nA
181        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
182        the same is true. There doesn't seem any very clean way out of this, but
183        what I have chosen to do makes the common cases work: PCRE now takes note
184        of whether there can be an explicit match for \r or \n anywhere in the
185        pattern, and if so, 7.0/46 no longer applies. As part of this change,
186        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
187        pattern has explicit CR or LF references.
188    
189    29. Added (*CR) etc for changing newline setting at start of pattern.
190    
191    
192    Version 7.2 19-Jun-07
193  ---------------------  ---------------------
194    
195   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
# Line 68  Version 7.2 19-June-07 Line 256  Version 7.2 19-June-07
256        pcrecpp::RE("a*").FullMatch("aaa") matches, while        pcrecpp::RE("a*").FullMatch("aaa") matches, while
257        pcrecpp::RE("a*?").FullMatch("aaa") does not, and        pcrecpp::RE("a*?").FullMatch("aaa") does not, and
258        pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.        pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
259    
260  12. If \p or \P was used in non-UTF-8 mode on a character greater than 127  12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
261      it matched the wrong number of bytes.      it matched the wrong number of bytes.
262    
263    
264  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07

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