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revision 134 by ph10, Mon Mar 26 16:00:17 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 7.1 12-Mar-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,
196        which is apparently normally available under Windows.
197    
198     2. Re-jig the pcregrep tests with different newline settings in an attempt
199        to make them independent of the local environment's newline setting.
200    
201     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
202    
203     4. Some of the "internals" tests were previously cut out when the link size
204        was not 2, because the output contained actual offsets. The recent new
205        "Z" feature of pcretest means that these can be cut out, making the tests
206        usable with all link sizes.
207    
208     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
209        stack recursion. This gives a massive performance boost under BSD, but just
210        a small improvement under Linux. However, it saves one field in the frame
211        in all cases.
212    
213     6. Added more features from the forthcoming Perl 5.10:
214    
215        (a) (?-n) (where n is a string of digits) is a relative subroutine or
216            recursion call. It refers to the nth most recently opened parentheses.
217    
218        (b) (?+n) is also a relative subroutine call; it refers to the nth next
219            to be opened parentheses.
220    
221        (c) Conditions that refer to capturing parentheses can be specified
222            relatively, for example, (?(-2)... or (?(+3)...
223    
224        (d) \K resets the start of the current match so that everything before
225            is not part of it.
226    
227        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
228    
229        (f) \g{name} is another synonym - part of Perl 5.10's unification of
230            reference syntax.
231    
232        (g) (?| introduces a group in which the numbering of parentheses in each
233            alternative starts with the same number.
234    
235        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
236    
237     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
238        PCRE_INFO_JCHANGED.
239    
240     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
241        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
242        for detecting groups that can match an empty string.
243    
244     9. A pattern with a very large number of alternatives (more than several
245        hundred) was running out of internal workspace during the pre-compile
246        phase, where pcre_compile() figures out how much memory will be needed. A
247        bit of new cunning has reduced the workspace needed for groups with
248        alternatives. The 1000-alternative test pattern now uses 12 bytes of
249        workspace instead of running out of the 4096 that are available.
250    
251    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
252    
253    11. Applied patch from Google to remove an optimization that didn't quite work.
254        The report of the bug said:
255    
256          pcrecpp::RE("a*").FullMatch("aaa") matches, while
257          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
258          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
261        it matched the wrong number of bytes.
262    
263    
264    Version 7.1 24-Apr-07
265  ---------------------  ---------------------
266    
267   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 33  Version 7.1 12-Mar-07 Line 293  Version 7.1 12-Mar-07
293   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
294      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
295      makevp.bat for the current PCRE, using the additional files      makevp.bat for the current PCRE, using the additional files
296      makevp-c.txt, makevp-l.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
297    
298   6. A Windows user reported a minor discrepancy with test 2, which turned out   6. A Windows user reported a minor discrepancy with test 2, which turned out
299      to be caused by a trailing space on an input line that had got lost in his      to be caused by a trailing space on an input line that had got lost in his
# Line 127  Version 7.1 12-Mar-07 Line 387  Version 7.1 12-Mar-07
387      in an attempt to make files that differ only in their line terminators      in an attempt to make files that differ only in their line terminators
388      compare equal. This works on Linux.      compare equal. This works on Linux.
389    
390    17. Under certain error circumstances pcregrep might try to free random memory
391        as it exited. This is now fixed, thanks to valgrind.
392    
393    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
394        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
395        was because its rules for how to advance for /g after matching an empty
396        string at the end of a line did not allow for this case. They now check for
397        it specially.
398    
399    20. pcretest is supposed to handle patterns and data of any length, by
400        extending its buffers when necessary. It was getting this wrong when the
401        buffer for a data line had to be extended.
402    
403    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
404        CRLF as a newline sequence.
405    
406    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
407        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
408        I have nevertheless tidied it up.
409    
410    23. Added some casts to kill warnings from HP-UX ia64 compiler.
411    
412    24. Added a man page for pcre-config.
413    
414    
415  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
416  ---------------------  ---------------------

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