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revision 168 by ph10, Tue May 29 15:18:18 2007 UTC revision 269 by ph10, Fri Nov 16 16:22:24 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 01-May-07  Version 7.5 12-Nov-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing).
25    
26    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
27        this is right because (?- can be followed by option settings as well as by
28        digits. I have, however, made the messages clearer.
29    
30    
31    Version 7.4 21-Sep-07
32    ---------------------
33    
34    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
35        means that a class such as [\s] counted as "explicit reference to CR or
36        LF". That isn't really right - the whole point of the change was to try to
37        help when there was an actual mention of one of the two characters. So now
38        the change happens only if \r or \n (or a literal CR or LF) character is
39        encountered.
40    
41    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
42        of both had grown to the point where there were only 3 bits left.
43        Fortunately, there was spare space in the data structure, and so I have
44        moved the internal flags into a new 16-bit field to free up more option
45        bits.
46    
47    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
48        but did not set the internal JCHANGED flag - either of these is enough to
49        control the way the "get" function works - but the PCRE_INFO_JCHANGED
50        facility is supposed to tell if (?J) was ever used, so now (?J) at the
51        start sets both bits.
52    
53    4.  Added options (at build time, compile time, exec time) to change \R from
54        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
55    
56    5.  doc/pcresyntax.html was missing from the distribution.
57    
58    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
59        compatibility, even though it is no longer used.
60    
61    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
62        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
63        windows.h file is present (where different names are used). [This was
64        reversed later after testing - see 16 below.]
65    
66    8.  Changed all #include <config.h> to #include "config.h". There were also
67        some further <pcre.h> cases that I changed to "pcre.h".
68    
69    9.  When pcregrep was used with the --colour option, it missed the line ending
70        sequence off the lines that it output.
71    
72    10. It was pointed out to me that arrays of string pointers cause lots of
73        relocations when a shared library is dynamically loaded. A technique of
74        using a single long string with a table of offsets can drastically reduce
75        these. I have refactored PCRE in four places to do this. The result is
76        dramatic:
77    
78          Originally:                          290
79          After changing UCP table:            187
80          After changing error message table:   43
81          After changing table of "verbs"       36
82          After changing table of Posix names   22
83    
84        Thanks to the folks working on Gregex for glib for this insight.
85    
86    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
87        unicode-properties was also set.
88    
89    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
90    
91    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
92        checked only for CRLF.
93    
94    14. Added casts to pcretest.c to avoid compiler warnings.
95    
96    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
97    
98    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
99        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
100        entirely. This removes changes made in 7 above.
101    
102    17. The CMake files have been updated, and there is now more information about
103        building with CMake in the NON-UNIX-USE document.
104    
105    
106    Version 7.3 28-Aug-07
107    ---------------------
108    
109     1. In the rejigging of the build system that eventually resulted in 7.1, the
110        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
111        brackets there is not right, since it causes compilers to look for an
112        installed pcre.h, not the version that is in the source that is being
113        compiled (which of course may be different). I have changed it back to:
114    
115          #include "pcre.h"
116    
117        I have a vague recollection that the change was concerned with compiling in
118        different directories, but in the new build system, that is taken care of
119        by the VPATH setting the Makefile.
120    
121     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
122        when the subject happened to end in the byte 0x85 (e.g. if the last
123        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
124        characters but of course it shouldn't be taken as a newline when it is part
125        of another character. The bug was that, for an unlimited repeat of . in
126        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
127        characters when looking for a newline.
128    
129     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
130    
131     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
132        in debug output.
133    
134     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
135        long printing in the pcrecpp unittest when running under MinGW.
136    
137     6. ESC_K was left out of the EBCDIC table.
138    
139     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
140        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
141        limit also applies to "virtual nesting" when a pattern is recursive, and in
142        this case 1000 isn't so big. I have been able to remove this limit at the
143        expense of backing off one optimization in certain circumstances. Normally,
144        when pcre_exec() would call its internal match() function recursively and
145        immediately return the result unconditionally, it uses a "tail recursion"
146        feature to save stack. However, when a subpattern that can match an empty
147        string has an unlimited repetition quantifier, it no longer makes this
148        optimization. That gives it a stack frame in which to save the data for
149        checking that an empty string has been matched. Previously this was taken
150        from the 1000-entry workspace that had been reserved. So now there is no
151        explicit limit, but more stack is used.
152    
153     8. Applied Daniel's patches to solve problems with the import/export magic
154        syntax that is required for Windows, and which was going wrong for the
155        pcreposix and pcrecpp parts of the library. These were overlooked when this
156        problem was solved for the main library.
157    
158     9. There were some crude static tests to avoid integer overflow when computing
159        the size of patterns that contain repeated groups with explicit upper
160        limits. As the maximum quantifier is 65535, the maximum group length was
161        set at 30,000 so that the product of these two numbers did not overflow a
162        32-bit integer. However, it turns out that people want to use groups that
163        are longer than 30,000 bytes (though not repeat them that many times).
164        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
165        made it possible to implement the integer overflow checks in a much more
166        dynamic way, which I have now done. The artificial limitation on group
167        length has been removed - we now have only the limit on the total length of
168        the compiled pattern, which depends on the LINK_SIZE setting.
169    
170    10. Fixed a bug in the documentation for get/copy named substring when
171        duplicate names are permitted. If none of the named substrings are set, the
172        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
173        empty string.
174    
175    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
176        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
177        because the ] is interpreted as the first data character and the
178        terminating ] is not found. PCRE has been made compatible with Perl in this
179        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
180        cause memory overwriting.
181    
182    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
183        string has been matched (to stop an infinite loop). It was not recognizing
184        a conditional subpattern that could match an empty string if that
185        subpattern was within another subpattern. For example, it looped when
186        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
187        condition was not nested. This bug has been fixed.
188    
189    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
190        past the start of the subject in the presence of bytes with the top bit
191        set, for example "\x8aBCD".
192    
193    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
194        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
195    
196    14. Optimized (?!) to (*FAIL).
197    
198    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
199        This restricts code points to be within the range 0 to 0x10FFFF, excluding
200        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
201        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
202        does: it's just the validity check that is more restrictive.
203    
204    16. Inserted checks for integer overflows during escape sequence (backslash)
205        processing, and also fixed erroneous offset values for syntax errors during
206        backslash processing.
207    
208    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
209        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
210    
211    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
212        caused an overrun.
213    
214    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
215        something other than just ASCII characters) inside a group that had an
216        unlimited repeat caused a loop at compile time (while checking to see
217        whether the group could match an empty string).
218    
219    20. Debugging a pattern containing \p or \P could cause a crash. For example,
220        [\P{Any}] did so. (Error in the code for printing property names.)
221    
222    21. An orphan \E inside a character class could cause a crash.
223    
224    22. A repeated capturing bracket such as (A)? could cause a wild memory
225        reference during compilation.
226    
227    23. There are several functions in pcre_compile() that scan along a compiled
228        expression for various reasons (e.g. to see if it's fixed length for look
229        behind). There were bugs in these functions when a repeated \p or \P was
230        present in the pattern. These operators have additional parameters compared
231        with \d, etc, and these were not being taken into account when moving along
232        the compiled data. Specifically:
233    
234        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
235            length.
236    
237        (b) An item such as \pL+ within a repeated group could cause crashes or
238            loops.
239    
240        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
241            "reference to non-existent subpattern" error.
242    
243        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
244    
245    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
246        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
247    
248    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
249    
250    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
251        character were causing crashes (broken optimization).
252    
253    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
254        \p or \P) caused a compile-time loop.
255    
256    28. More problems have arisen in unanchored patterns when CRLF is a valid line
257        break. For example, the unstudied pattern [\r\n]A does not match the string
258        "\r\nA" because change 7.0/46 below moves the current point on by two
259        characters after failing to match at the start. However, the pattern \nA
260        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
261        the same is true. There doesn't seem any very clean way out of this, but
262        what I have chosen to do makes the common cases work: PCRE now takes note
263        of whether there can be an explicit match for \r or \n anywhere in the
264        pattern, and if so, 7.0/46 no longer applies. As part of this change,
265        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
266        pattern has explicit CR or LF references.
267    
268    29. Added (*CR) etc for changing newline setting at start of pattern.
269    
270    
271    Version 7.2 19-Jun-07
272  ---------------------  ---------------------
273    
274   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 21  Version 7.2 01-May-07 Line 288  Version 7.2 01-May-07
288      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
289      a small improvement under Linux. However, it saves one field in the frame      a small improvement under Linux. However, it saves one field in the frame
290      in all cases.      in all cases.
291    
292   6. Added more features from the forthcoming Perl 5.10:   6. Added more features from the forthcoming Perl 5.10:
293    
294      (a) (?-n) (where n is a string of digits) is a relative subroutine or      (a) (?-n) (where n is a string of digits) is a relative subroutine or
295          recursion call. It refers to the nth most recently opened parentheses.          recursion call. It refers to the nth most recently opened parentheses.
296    
297      (b) (?+n) is also a relative subroutine call; it refers to the nth next      (b) (?+n) is also a relative subroutine call; it refers to the nth next
298          to be opened parentheses.          to be opened parentheses.
299    
300      (c) Conditions that refer to capturing parentheses can be specified      (c) Conditions that refer to capturing parentheses can be specified
301          relatively, for example, (?(-2)... or (?(+3)...          relatively, for example, (?(-2)... or (?(+3)...
302    
303      (d) \K resets the start of the current match so that everything before      (d) \K resets the start of the current match so that everything before
304          is not part of it.          is not part of it.
305    
306        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
307    
308        (f) \g{name} is another synonym - part of Perl 5.10's unification of
309            reference syntax.
310    
311        (g) (?| introduces a group in which the numbering of parentheses in each
312            alternative starts with the same number.
313    
314        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
315    
316     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
317        PCRE_INFO_JCHANGED.
318    
319     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
320        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
321        for detecting groups that can match an empty string.
322    
323     9. A pattern with a very large number of alternatives (more than several
324        hundred) was running out of internal workspace during the pre-compile
325        phase, where pcre_compile() figures out how much memory will be needed. A
326        bit of new cunning has reduced the workspace needed for groups with
327        alternatives. The 1000-alternative test pattern now uses 12 bytes of
328        workspace instead of running out of the 4096 that are available.
329    
330    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
331    
332    11. Applied patch from Google to remove an optimization that didn't quite work.
333        The report of the bug said:
334    
335          pcrecpp::RE("a*").FullMatch("aaa") matches, while
336          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
337          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
338    
339    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
340        it matched the wrong number of bytes.
341    
342    
343  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07

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