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revision 131 by ph10, Mon Mar 26 15:10:12 2007 UTC revision 236 by ph10, Tue Sep 11 12:57:06 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    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    
42    Version 7.3 28-Aug-07
43    ---------------------
44    
45     1. In the rejigging of the build system that eventually resulted in 7.1, the
46        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
47        brackets there is not right, since it causes compilers to look for an
48        installed pcre.h, not the version that is in the source that is being
49        compiled (which of course may be different). I have changed it back to:
50    
51          #include "pcre.h"
52    
53        I have a vague recollection that the change was concerned with compiling in
54        different directories, but in the new build system, that is taken care of
55        by the VPATH setting the Makefile.
56    
57     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
58        when the subject happened to end in the byte 0x85 (e.g. if the last
59        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
60        characters but of course it shouldn't be taken as a newline when it is part
61        of another character. The bug was that, for an unlimited repeat of . in
62        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
63        characters when looking for a newline.
64    
65     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
66    
67     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
68        in debug output.
69    
70     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
71        long printing in the pcrecpp unittest when running under MinGW.
72    
73     6. ESC_K was left out of the EBCDIC table.
74    
75     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
76        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
77        limit also applies to "virtual nesting" when a pattern is recursive, and in
78        this case 1000 isn't so big. I have been able to remove this limit at the
79        expense of backing off one optimization in certain circumstances. Normally,
80        when pcre_exec() would call its internal match() function recursively and
81        immediately return the result unconditionally, it uses a "tail recursion"
82        feature to save stack. However, when a subpattern that can match an empty
83        string has an unlimited repetition quantifier, it no longer makes this
84        optimization. That gives it a stack frame in which to save the data for
85        checking that an empty string has been matched. Previously this was taken
86        from the 1000-entry workspace that had been reserved. So now there is no
87        explicit limit, but more stack is used.
88    
89     8. Applied Daniel's patches to solve problems with the import/export magic
90        syntax that is required for Windows, and which was going wrong for the
91        pcreposix and pcrecpp parts of the library. These were overlooked when this
92        problem was solved for the main library.
93    
94     9. There were some crude static tests to avoid integer overflow when computing
95        the size of patterns that contain repeated groups with explicit upper
96        limits. As the maximum quantifier is 65535, the maximum group length was
97        set at 30,000 so that the product of these two numbers did not overflow a
98        32-bit integer. However, it turns out that people want to use groups that
99        are longer than 30,000 bytes (though not repeat them that many times).
100        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
101        made it possible to implement the integer overflow checks in a much more
102        dynamic way, which I have now done. The artificial limitation on group
103        length has been removed - we now have only the limit on the total length of
104        the compiled pattern, which depends on the LINK_SIZE setting.
105    
106    10. Fixed a bug in the documentation for get/copy named substring when
107        duplicate names are permitted. If none of the named substrings are set, the
108        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
109        empty string.
110    
111    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
112        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
113        because the ] is interpreted as the first data character and the
114        terminating ] is not found. PCRE has been made compatible with Perl in this
115        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
116        cause memory overwriting.
117    
118    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
119        string has been matched (to stop an infinite loop). It was not recognizing
120        a conditional subpattern that could match an empty string if that
121        subpattern was within another subpattern. For example, it looped when
122        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
123        condition was not nested. This bug has been fixed.
124    
125    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
126        past the start of the subject in the presence of bytes with the top bit
127        set, for example "\x8aBCD".
128    
129    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
130        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
131    
132    14. Optimized (?!) to (*FAIL).
133    
134    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
135        This restricts code points to be within the range 0 to 0x10FFFF, excluding
136        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
137        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
138        does: it's just the validity check that is more restrictive.
139    
140    16. Inserted checks for integer overflows during escape sequence (backslash)
141        processing, and also fixed erroneous offset values for syntax errors during
142        backslash processing.
143    
144    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
145        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
146    
147    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
148        caused an overrun.
149    
150    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
151        something other than just ASCII characters) inside a group that had an
152        unlimited repeat caused a loop at compile time (while checking to see
153        whether the group could match an empty string).
154    
155    20. Debugging a pattern containing \p or \P could cause a crash. For example,
156        [\P{Any}] did so. (Error in the code for printing property names.)
157    
158    21. An orphan \E inside a character class could cause a crash.
159    
160    22. A repeated capturing bracket such as (A)? could cause a wild memory
161        reference during compilation.
162    
163    23. There are several functions in pcre_compile() that scan along a compiled
164        expression for various reasons (e.g. to see if it's fixed length for look
165        behind). There were bugs in these functions when a repeated \p or \P was
166        present in the pattern. These operators have additional parameters compared
167        with \d, etc, and these were not being taken into account when moving along
168        the compiled data. Specifically:
169    
170        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
171            length.
172    
173        (b) An item such as \pL+ within a repeated group could cause crashes or
174            loops.
175    
176        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
177            "reference to non-existent subpattern" error.
178    
179        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
180    
181    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
182        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
183    
184    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
185    
186    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
187        character were causing crashes (broken optimization).
188    
189    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
190        \p or \P) caused a compile-time loop.
191    
192    28. More problems have arisen in unanchored patterns when CRLF is a valid line
193        break. For example, the unstudied pattern [\r\n]A does not match the string
194        "\r\nA" because change 7.0/46 below moves the current point on by two
195        characters after failing to match at the start. However, the pattern \nA
196        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
197        the same is true. There doesn't seem any very clean way out of this, but
198        what I have chosen to do makes the common cases work: PCRE now takes note
199        of whether there can be an explicit match for \r or \n anywhere in the
200        pattern, and if so, 7.0/46 no longer applies. As part of this change,
201        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
202        pattern has explicit CR or LF references.
203    
204    29. Added (*CR) etc for changing newline setting at start of pattern.
205    
206    
207    Version 7.2 19-Jun-07
208    ---------------------
209    
210     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
211        which is apparently normally available under Windows.
212    
213     2. Re-jig the pcregrep tests with different newline settings in an attempt
214        to make them independent of the local environment's newline setting.
215    
216     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
217    
218     4. Some of the "internals" tests were previously cut out when the link size
219        was not 2, because the output contained actual offsets. The recent new
220        "Z" feature of pcretest means that these can be cut out, making the tests
221        usable with all link sizes.
222    
223     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
224        stack recursion. This gives a massive performance boost under BSD, but just
225        a small improvement under Linux. However, it saves one field in the frame
226        in all cases.
227    
228     6. Added more features from the forthcoming Perl 5.10:
229    
230        (a) (?-n) (where n is a string of digits) is a relative subroutine or
231            recursion call. It refers to the nth most recently opened parentheses.
232    
233        (b) (?+n) is also a relative subroutine call; it refers to the nth next
234            to be opened parentheses.
235    
236        (c) Conditions that refer to capturing parentheses can be specified
237            relatively, for example, (?(-2)... or (?(+3)...
238    
239        (d) \K resets the start of the current match so that everything before
240            is not part of it.
241    
242        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
243    
244        (f) \g{name} is another synonym - part of Perl 5.10's unification of
245            reference syntax.
246    
247        (g) (?| introduces a group in which the numbering of parentheses in each
248            alternative starts with the same number.
249    
250        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
251    
252     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
253        PCRE_INFO_JCHANGED.
254    
255     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
256        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
257        for detecting groups that can match an empty string.
258    
259     9. A pattern with a very large number of alternatives (more than several
260        hundred) was running out of internal workspace during the pre-compile
261        phase, where pcre_compile() figures out how much memory will be needed. A
262        bit of new cunning has reduced the workspace needed for groups with
263        alternatives. The 1000-alternative test pattern now uses 12 bytes of
264        workspace instead of running out of the 4096 that are available.
265    
266    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
267    
268    11. Applied patch from Google to remove an optimization that didn't quite work.
269        The report of the bug said:
270    
271          pcrecpp::RE("a*").FullMatch("aaa") matches, while
272          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
273          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
274    
275    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
276        it matched the wrong number of bytes.
277    
278    
279    Version 7.1 24-Apr-07
280  ---------------------  ---------------------
281    
282   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 308  Version 7.1 12-Mar-07
308   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
309      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
310      makevp.bat for the current PCRE, using the additional files      makevp.bat for the current PCRE, using the additional files
311      makevp-c.txt, makevp-l.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
312    
313   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
314      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 115  Version 7.1 12-Mar-07 Line 390  Version 7.1 12-Mar-07
390    
391  14. If erroroffset was passed as NULL to pcre_compile, it provoked a  14. If erroroffset was passed as NULL to pcre_compile, it provoked a
392      segmentation fault instead of returning the appropriate error message.      segmentation fault instead of returning the appropriate error message.
393    
394  15. In multiline mode when the newline sequence was set to "any", the pattern  15. In multiline mode when the newline sequence was set to "any", the pattern
395      ^$ would give a match between the \r and \n of a subject such as "A\r\nB".      ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
396      This doesn't seem right; it now treats the CRLF combination as the line      This doesn't seem right; it now treats the CRLF combination as the line
397      ending, and so does not match in that case. It's only a pattern such as ^$      ending, and so does not match in that case. It's only a pattern such as ^$
398      that would hit this one: something like ^ABC$ would have failed after \r      that would hit this one: something like ^ABC$ would have failed after \r
399      and then tried again after \r\n.      and then tried again after \r\n.
400    
401  16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"  16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
402      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
403      compare equal. This works on Linux.      compare equal. This works on Linux.
404    
405    17. Under certain error circumstances pcregrep might try to free random memory
406        as it exited. This is now fixed, thanks to valgrind.
407    
408    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
409        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
410        was because its rules for how to advance for /g after matching an empty
411        string at the end of a line did not allow for this case. They now check for
412        it specially.
413    
414    20. pcretest is supposed to handle patterns and data of any length, by
415        extending its buffers when necessary. It was getting this wrong when the
416        buffer for a data line had to be extended.
417    
418    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
419        CRLF as a newline sequence.
420    
421    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
422        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
423        I have nevertheless tidied it up.
424    
425    23. Added some casts to kill warnings from HP-UX ia64 compiler.
426    
427    24. Added a man page for pcre-config.
428    
429    
430  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06

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