/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 157 by ph10, Tue May 1 09:19:56 2007 UTC revision 245 by ph10, Fri Sep 14 10:06:05 2007 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 01-May-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    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
28    
29    5.  doc/pcresyntax.html was missing from the distribution.
30    
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
33    
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 (where
36        different names are used).
37    
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
40    
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
43    
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
49    
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
55    
56        Thanks to the folks working on Gregex for glib for this insight.
57    
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
60    
61    12. Updated the RunTest script to miss out tests that don't work if \R is
62        defaulted to ANYCRLF.
63    
64    
65    Version 7.3 28-Aug-07
66    ---------------------
67    
68     1. In the rejigging of the build system that eventually resulted in 7.1, the
69        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
70        brackets there is not right, since it causes compilers to look for an
71        installed pcre.h, not the version that is in the source that is being
72        compiled (which of course may be different). I have changed it back to:
73    
74          #include "pcre.h"
75    
76        I have a vague recollection that the change was concerned with compiling in
77        different directories, but in the new build system, that is taken care of
78        by the VPATH setting the Makefile.
79    
80     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
81        when the subject happened to end in the byte 0x85 (e.g. if the last
82        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
83        characters but of course it shouldn't be taken as a newline when it is part
84        of another character. The bug was that, for an unlimited repeat of . in
85        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
86        characters when looking for a newline.
87    
88     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
89    
90     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
91        in debug output.
92    
93     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
94        long printing in the pcrecpp unittest when running under MinGW.
95    
96     6. ESC_K was left out of the EBCDIC table.
97    
98     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
99        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
100        limit also applies to "virtual nesting" when a pattern is recursive, and in
101        this case 1000 isn't so big. I have been able to remove this limit at the
102        expense of backing off one optimization in certain circumstances. Normally,
103        when pcre_exec() would call its internal match() function recursively and
104        immediately return the result unconditionally, it uses a "tail recursion"
105        feature to save stack. However, when a subpattern that can match an empty
106        string has an unlimited repetition quantifier, it no longer makes this
107        optimization. That gives it a stack frame in which to save the data for
108        checking that an empty string has been matched. Previously this was taken
109        from the 1000-entry workspace that had been reserved. So now there is no
110        explicit limit, but more stack is used.
111    
112     8. Applied Daniel's patches to solve problems with the import/export magic
113        syntax that is required for Windows, and which was going wrong for the
114        pcreposix and pcrecpp parts of the library. These were overlooked when this
115        problem was solved for the main library.
116    
117     9. There were some crude static tests to avoid integer overflow when computing
118        the size of patterns that contain repeated groups with explicit upper
119        limits. As the maximum quantifier is 65535, the maximum group length was
120        set at 30,000 so that the product of these two numbers did not overflow a
121        32-bit integer. However, it turns out that people want to use groups that
122        are longer than 30,000 bytes (though not repeat them that many times).
123        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
124        made it possible to implement the integer overflow checks in a much more
125        dynamic way, which I have now done. The artificial limitation on group
126        length has been removed - we now have only the limit on the total length of
127        the compiled pattern, which depends on the LINK_SIZE setting.
128    
129    10. Fixed a bug in the documentation for get/copy named substring when
130        duplicate names are permitted. If none of the named substrings are set, the
131        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
132        empty string.
133    
134    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
135        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
136        because the ] is interpreted as the first data character and the
137        terminating ] is not found. PCRE has been made compatible with Perl in this
138        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
139        cause memory overwriting.
140    
141    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
142        string has been matched (to stop an infinite loop). It was not recognizing
143        a conditional subpattern that could match an empty string if that
144        subpattern was within another subpattern. For example, it looped when
145        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
146        condition was not nested. This bug has been fixed.
147    
148    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
149        past the start of the subject in the presence of bytes with the top bit
150        set, for example "\x8aBCD".
151    
152    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
153        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
154    
155    14. Optimized (?!) to (*FAIL).
156    
157    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
158        This restricts code points to be within the range 0 to 0x10FFFF, excluding
159        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
160        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
161        does: it's just the validity check that is more restrictive.
162    
163    16. Inserted checks for integer overflows during escape sequence (backslash)
164        processing, and also fixed erroneous offset values for syntax errors during
165        backslash processing.
166    
167    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
168        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
169    
170    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
171        caused an overrun.
172    
173    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
174        something other than just ASCII characters) inside a group that had an
175        unlimited repeat caused a loop at compile time (while checking to see
176        whether the group could match an empty string).
177    
178    20. Debugging a pattern containing \p or \P could cause a crash. For example,
179        [\P{Any}] did so. (Error in the code for printing property names.)
180    
181    21. An orphan \E inside a character class could cause a crash.
182    
183    22. A repeated capturing bracket such as (A)? could cause a wild memory
184        reference during compilation.
185    
186    23. There are several functions in pcre_compile() that scan along a compiled
187        expression for various reasons (e.g. to see if it's fixed length for look
188        behind). There were bugs in these functions when a repeated \p or \P was
189        present in the pattern. These operators have additional parameters compared
190        with \d, etc, and these were not being taken into account when moving along
191        the compiled data. Specifically:
192    
193        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
194            length.
195    
196        (b) An item such as \pL+ within a repeated group could cause crashes or
197            loops.
198    
199        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
200            "reference to non-existent subpattern" error.
201    
202        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
203    
204    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
205        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
206    
207    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
208    
209    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
210        character were causing crashes (broken optimization).
211    
212    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
213        \p or \P) caused a compile-time loop.
214    
215    28. More problems have arisen in unanchored patterns when CRLF is a valid line
216        break. For example, the unstudied pattern [\r\n]A does not match the string
217        "\r\nA" because change 7.0/46 below moves the current point on by two
218        characters after failing to match at the start. However, the pattern \nA
219        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
220        the same is true. There doesn't seem any very clean way out of this, but
221        what I have chosen to do makes the common cases work: PCRE now takes note
222        of whether there can be an explicit match for \r or \n anywhere in the
223        pattern, and if so, 7.0/46 no longer applies. As part of this change,
224        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
225        pattern has explicit CR or LF references.
226    
227    29. Added (*CR) etc for changing newline setting at start of pattern.
228    
229    
230    Version 7.2 19-Jun-07
231  ---------------------  ---------------------
232    
233   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,
234      which is apparently normally available under Windows.      which is apparently normally available under Windows.
235    
236     2. Re-jig the pcregrep tests with different newline settings in an attempt
237        to make them independent of the local environment's newline setting.
238    
239     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
240    
241     4. Some of the "internals" tests were previously cut out when the link size
242        was not 2, because the output contained actual offsets. The recent new
243        "Z" feature of pcretest means that these can be cut out, making the tests
244        usable with all link sizes.
245    
246     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
247        stack recursion. This gives a massive performance boost under BSD, but just
248        a small improvement under Linux. However, it saves one field in the frame
249        in all cases.
250    
251     6. Added more features from the forthcoming Perl 5.10:
252    
253        (a) (?-n) (where n is a string of digits) is a relative subroutine or
254            recursion call. It refers to the nth most recently opened parentheses.
255    
256        (b) (?+n) is also a relative subroutine call; it refers to the nth next
257            to be opened parentheses.
258    
259        (c) Conditions that refer to capturing parentheses can be specified
260            relatively, for example, (?(-2)... or (?(+3)...
261    
262        (d) \K resets the start of the current match so that everything before
263            is not part of it.
264    
265        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
266    
267        (f) \g{name} is another synonym - part of Perl 5.10's unification of
268            reference syntax.
269    
270        (g) (?| introduces a group in which the numbering of parentheses in each
271            alternative starts with the same number.
272    
273        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
274    
275     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
276        PCRE_INFO_JCHANGED.
277    
278     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
279        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
280        for detecting groups that can match an empty string.
281    
282     9. A pattern with a very large number of alternatives (more than several
283        hundred) was running out of internal workspace during the pre-compile
284        phase, where pcre_compile() figures out how much memory will be needed. A
285        bit of new cunning has reduced the workspace needed for groups with
286        alternatives. The 1000-alternative test pattern now uses 12 bytes of
287        workspace instead of running out of the 4096 that are available.
288    
289    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
290    
291    11. Applied patch from Google to remove an optimization that didn't quite work.
292        The report of the bug said:
293    
294          pcrecpp::RE("a*").FullMatch("aaa") matches, while
295          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
296          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
297    
298    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
299        it matched the wrong number of bytes.
300    
301    
302  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
303  ---------------------  ---------------------

Legend:
Removed from v.157  
changed lines
  Added in v.245

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12