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revision 165 by ph10, Wed May 9 10:50:57 2007 UTC revision 270 by ph10, Fri Nov 16 19:55:16 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    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
31        than the number used in the conditional) now cause a compile-time error.
32        This is actually not compatible with Perl, which accepts such patterns, but
33        treats the conditional as always being FALSE (as PCRE used to), but it
34        seems to me that giving a diagnostic is better.
35    
36    
37    Version 7.4 21-Sep-07
38    ---------------------
39    
40    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
41        means that a class such as [\s] counted as "explicit reference to CR or
42        LF". That isn't really right - the whole point of the change was to try to
43        help when there was an actual mention of one of the two characters. So now
44        the change happens only if \r or \n (or a literal CR or LF) character is
45        encountered.
46    
47    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
48        of both had grown to the point where there were only 3 bits left.
49        Fortunately, there was spare space in the data structure, and so I have
50        moved the internal flags into a new 16-bit field to free up more option
51        bits.
52    
53    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
54        but did not set the internal JCHANGED flag - either of these is enough to
55        control the way the "get" function works - but the PCRE_INFO_JCHANGED
56        facility is supposed to tell if (?J) was ever used, so now (?J) at the
57        start sets both bits.
58    
59    4.  Added options (at build time, compile time, exec time) to change \R from
60        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
61    
62    5.  doc/pcresyntax.html was missing from the distribution.
63    
64    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
65        compatibility, even though it is no longer used.
66    
67    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
68        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
69        windows.h file is present (where different names are used). [This was
70        reversed later after testing - see 16 below.]
71    
72    8.  Changed all #include <config.h> to #include "config.h". There were also
73        some further <pcre.h> cases that I changed to "pcre.h".
74    
75    9.  When pcregrep was used with the --colour option, it missed the line ending
76        sequence off the lines that it output.
77    
78    10. It was pointed out to me that arrays of string pointers cause lots of
79        relocations when a shared library is dynamically loaded. A technique of
80        using a single long string with a table of offsets can drastically reduce
81        these. I have refactored PCRE in four places to do this. The result is
82        dramatic:
83    
84          Originally:                          290
85          After changing UCP table:            187
86          After changing error message table:   43
87          After changing table of "verbs"       36
88          After changing table of Posix names   22
89    
90        Thanks to the folks working on Gregex for glib for this insight.
91    
92    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
93        unicode-properties was also set.
94    
95    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
96    
97    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
98        checked only for CRLF.
99    
100    14. Added casts to pcretest.c to avoid compiler warnings.
101    
102    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
103    
104    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
105        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
106        entirely. This removes changes made in 7 above.
107    
108    17. The CMake files have been updated, and there is now more information about
109        building with CMake in the NON-UNIX-USE document.
110    
111    
112    Version 7.3 28-Aug-07
113    ---------------------
114    
115     1. In the rejigging of the build system that eventually resulted in 7.1, the
116        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
117        brackets there is not right, since it causes compilers to look for an
118        installed pcre.h, not the version that is in the source that is being
119        compiled (which of course may be different). I have changed it back to:
120    
121          #include "pcre.h"
122    
123        I have a vague recollection that the change was concerned with compiling in
124        different directories, but in the new build system, that is taken care of
125        by the VPATH setting the Makefile.
126    
127     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
128        when the subject happened to end in the byte 0x85 (e.g. if the last
129        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
130        characters but of course it shouldn't be taken as a newline when it is part
131        of another character. The bug was that, for an unlimited repeat of . in
132        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
133        characters when looking for a newline.
134    
135     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
136    
137     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
138        in debug output.
139    
140     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
141        long printing in the pcrecpp unittest when running under MinGW.
142    
143     6. ESC_K was left out of the EBCDIC table.
144    
145     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
146        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
147        limit also applies to "virtual nesting" when a pattern is recursive, and in
148        this case 1000 isn't so big. I have been able to remove this limit at the
149        expense of backing off one optimization in certain circumstances. Normally,
150        when pcre_exec() would call its internal match() function recursively and
151        immediately return the result unconditionally, it uses a "tail recursion"
152        feature to save stack. However, when a subpattern that can match an empty
153        string has an unlimited repetition quantifier, it no longer makes this
154        optimization. That gives it a stack frame in which to save the data for
155        checking that an empty string has been matched. Previously this was taken
156        from the 1000-entry workspace that had been reserved. So now there is no
157        explicit limit, but more stack is used.
158    
159     8. Applied Daniel's patches to solve problems with the import/export magic
160        syntax that is required for Windows, and which was going wrong for the
161        pcreposix and pcrecpp parts of the library. These were overlooked when this
162        problem was solved for the main library.
163    
164     9. There were some crude static tests to avoid integer overflow when computing
165        the size of patterns that contain repeated groups with explicit upper
166        limits. As the maximum quantifier is 65535, the maximum group length was
167        set at 30,000 so that the product of these two numbers did not overflow a
168        32-bit integer. However, it turns out that people want to use groups that
169        are longer than 30,000 bytes (though not repeat them that many times).
170        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
171        made it possible to implement the integer overflow checks in a much more
172        dynamic way, which I have now done. The artificial limitation on group
173        length has been removed - we now have only the limit on the total length of
174        the compiled pattern, which depends on the LINK_SIZE setting.
175    
176    10. Fixed a bug in the documentation for get/copy named substring when
177        duplicate names are permitted. If none of the named substrings are set, the
178        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
179        empty string.
180    
181    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
182        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
183        because the ] is interpreted as the first data character and the
184        terminating ] is not found. PCRE has been made compatible with Perl in this
185        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
186        cause memory overwriting.
187    
188    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
189        string has been matched (to stop an infinite loop). It was not recognizing
190        a conditional subpattern that could match an empty string if that
191        subpattern was within another subpattern. For example, it looped when
192        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
193        condition was not nested. This bug has been fixed.
194    
195    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
196        past the start of the subject in the presence of bytes with the top bit
197        set, for example "\x8aBCD".
198    
199    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
200        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
201    
202    14. Optimized (?!) to (*FAIL).
203    
204    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
205        This restricts code points to be within the range 0 to 0x10FFFF, excluding
206        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
207        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
208        does: it's just the validity check that is more restrictive.
209    
210    16. Inserted checks for integer overflows during escape sequence (backslash)
211        processing, and also fixed erroneous offset values for syntax errors during
212        backslash processing.
213    
214    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
215        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
216    
217    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
218        caused an overrun.
219    
220    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
221        something other than just ASCII characters) inside a group that had an
222        unlimited repeat caused a loop at compile time (while checking to see
223        whether the group could match an empty string).
224    
225    20. Debugging a pattern containing \p or \P could cause a crash. For example,
226        [\P{Any}] did so. (Error in the code for printing property names.)
227    
228    21. An orphan \E inside a character class could cause a crash.
229    
230    22. A repeated capturing bracket such as (A)? could cause a wild memory
231        reference during compilation.
232    
233    23. There are several functions in pcre_compile() that scan along a compiled
234        expression for various reasons (e.g. to see if it's fixed length for look
235        behind). There were bugs in these functions when a repeated \p or \P was
236        present in the pattern. These operators have additional parameters compared
237        with \d, etc, and these were not being taken into account when moving along
238        the compiled data. Specifically:
239    
240        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
241            length.
242    
243        (b) An item such as \pL+ within a repeated group could cause crashes or
244            loops.
245    
246        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
247            "reference to non-existent subpattern" error.
248    
249        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
250    
251    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
252        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
253    
254    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
255    
256    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
257        character were causing crashes (broken optimization).
258    
259    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
260        \p or \P) caused a compile-time loop.
261    
262    28. More problems have arisen in unanchored patterns when CRLF is a valid line
263        break. For example, the unstudied pattern [\r\n]A does not match the string
264        "\r\nA" because change 7.0/46 below moves the current point on by two
265        characters after failing to match at the start. However, the pattern \nA
266        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
267        the same is true. There doesn't seem any very clean way out of this, but
268        what I have chosen to do makes the common cases work: PCRE now takes note
269        of whether there can be an explicit match for \r or \n anywhere in the
270        pattern, and if so, 7.0/46 no longer applies. As part of this change,
271        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
272        pattern has explicit CR or LF references.
273    
274    29. Added (*CR) etc for changing newline setting at start of pattern.
275    
276    
277    Version 7.2 19-Jun-07
278  ---------------------  ---------------------
279    
280   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 22  Version 7.2 01-May-07 Line 295  Version 7.2 01-May-07
295      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
296      in all cases.      in all cases.
297    
298     6. Added more features from the forthcoming Perl 5.10:
299    
300        (a) (?-n) (where n is a string of digits) is a relative subroutine or
301            recursion call. It refers to the nth most recently opened parentheses.
302    
303        (b) (?+n) is also a relative subroutine call; it refers to the nth next
304            to be opened parentheses.
305    
306        (c) Conditions that refer to capturing parentheses can be specified
307            relatively, for example, (?(-2)... or (?(+3)...
308    
309        (d) \K resets the start of the current match so that everything before
310            is not part of it.
311    
312        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
313    
314        (f) \g{name} is another synonym - part of Perl 5.10's unification of
315            reference syntax.
316    
317        (g) (?| introduces a group in which the numbering of parentheses in each
318            alternative starts with the same number.
319    
320        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
321    
322     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
323        PCRE_INFO_JCHANGED.
324    
325     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
326        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
327        for detecting groups that can match an empty string.
328    
329     9. A pattern with a very large number of alternatives (more than several
330        hundred) was running out of internal workspace during the pre-compile
331        phase, where pcre_compile() figures out how much memory will be needed. A
332        bit of new cunning has reduced the workspace needed for groups with
333        alternatives. The 1000-alternative test pattern now uses 12 bytes of
334        workspace instead of running out of the 4096 that are available.
335    
336    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
337    
338    11. Applied patch from Google to remove an optimization that didn't quite work.
339        The report of the bug said:
340    
341          pcrecpp::RE("a*").FullMatch("aaa") matches, while
342          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
343          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
344    
345    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
346        it matched the wrong number of bytes.
347    
348    
349  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
350  ---------------------  ---------------------

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