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revision 147 by ph10, Mon Apr 16 13:24:37 2007 UTC revision 221 by ph10, Fri Aug 17 09:25:08 2007 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 7.3 17-Aug-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    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
101    
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
105    
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
108    
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
111    
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
116    
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
119    
120    21. An orphan \E inside a character class could cause a crash.
121    
122    22. A repeated capturing bracket such as (A)? could cause a wild memory
123        reference during compilation.
124    
125    23. There are several functions in pcre_compile() that scan along a compiled
126        expression for various reasons (e.g. to see if it's fixed length for look
127        behind). There were bugs in these functions when a repeated \p or \P was
128        present in the pattern. These operators have additional parameters compared
129        with \d, etc, and these were not being taken into account when moving along
130        the compiled data. Specifically:
131    
132        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
133            length.
134    
135        (b) An item such as \pL+ within a repeated group could cause crashes or
136            loops.
137    
138        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
139            "reference to non-existent subpattern" error.
140    
141        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
142    
143    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
144        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
145    
146    
147    Version 7.2 19-Jun-07
148    ---------------------
149    
150     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
151        which is apparently normally available under Windows.
152    
153     2. Re-jig the pcregrep tests with different newline settings in an attempt
154        to make them independent of the local environment's newline setting.
155    
156     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
157    
158     4. Some of the "internals" tests were previously cut out when the link size
159        was not 2, because the output contained actual offsets. The recent new
160        "Z" feature of pcretest means that these can be cut out, making the tests
161        usable with all link sizes.
162    
163     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
164        stack recursion. This gives a massive performance boost under BSD, but just
165        a small improvement under Linux. However, it saves one field in the frame
166        in all cases.
167    
168     6. Added more features from the forthcoming Perl 5.10:
169    
170        (a) (?-n) (where n is a string of digits) is a relative subroutine or
171            recursion call. It refers to the nth most recently opened parentheses.
172    
173        (b) (?+n) is also a relative subroutine call; it refers to the nth next
174            to be opened parentheses.
175    
176        (c) Conditions that refer to capturing parentheses can be specified
177            relatively, for example, (?(-2)... or (?(+3)...
178    
179        (d) \K resets the start of the current match so that everything before
180            is not part of it.
181    
182        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
183    
184        (f) \g{name} is another synonym - part of Perl 5.10's unification of
185            reference syntax.
186    
187        (g) (?| introduces a group in which the numbering of parentheses in each
188            alternative starts with the same number.
189    
190        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
191    
192     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
193        PCRE_INFO_JCHANGED.
194    
195     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
196        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
197        for detecting groups that can match an empty string.
198    
199     9. A pattern with a very large number of alternatives (more than several
200        hundred) was running out of internal workspace during the pre-compile
201        phase, where pcre_compile() figures out how much memory will be needed. A
202        bit of new cunning has reduced the workspace needed for groups with
203        alternatives. The 1000-alternative test pattern now uses 12 bytes of
204        workspace instead of running out of the 4096 that are available.
205    
206    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
207    
208    11. Applied patch from Google to remove an optimization that didn't quite work.
209        The report of the bug said:
210    
211          pcrecpp::RE("a*").FullMatch("aaa") matches, while
212          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
213          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
214    
215    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
216        it matched the wrong number of bytes.
217    
218    
219    Version 7.1 24-Apr-07
220  ---------------------  ---------------------
221    
222   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
# Line 135  Version 7.1 12-Mar-07 Line 350  Version 7.1 12-Mar-07
350      was because its rules for how to advance for /g after matching an empty      was because its rules for how to advance for /g after matching an empty
351      string at the end of a line did not allow for this case. They now check for      string at the end of a line did not allow for this case. They now check for
352      it specially.      it specially.
353    
354  20. pcretest is supposed to handle patterns and data of any length, by  20. pcretest is supposed to handle patterns and data of any length, by
355      extending its buffers when necessary. It was getting this wrong when the      extending its buffers when necessary. It was getting this wrong when the
356      buffer for a data line had to be extended.      buffer for a data line had to be extended.
357    
358    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
359        CRLF as a newline sequence.
360    
361    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
362        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
363        I have nevertheless tidied it up.
364    
365    23. Added some casts to kill warnings from HP-UX ia64 compiler.
366    
367    24. Added a man page for pcre-config.
368    
369    
370  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
371  ---------------------  ---------------------

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