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revision 189 by ph10, Thu Jul 5 11:50:49 2007 UTC revision 263 by ph10, Mon Nov 12 16:53:25 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-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    
11    Version 7.4 21-Sep-07
12    ---------------------
13    
14    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
15        means that a class such as [\s] counted as "explicit reference to CR or
16        LF". That isn't really right - the whole point of the change was to try to
17        help when there was an actual mention of one of the two characters. So now
18        the change happens only if \r or \n (or a literal CR or LF) character is
19        encountered.
20    
21    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
22        of both had grown to the point where there were only 3 bits left.
23        Fortunately, there was spare space in the data structure, and so I have
24        moved the internal flags into a new 16-bit field to free up more option
25        bits.
26    
27    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
28        but did not set the internal JCHANGED flag - either of these is enough to
29        control the way the "get" function works - but the PCRE_INFO_JCHANGED
30        facility is supposed to tell if (?J) was ever used, so now (?J) at the
31        start sets both bits.
32    
33    4.  Added options (at build time, compile time, exec time) to change \R from
34        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
35    
36    5.  doc/pcresyntax.html was missing from the distribution.
37    
38    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
39        compatibility, even though it is no longer used.
40    
41    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
42        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
43        windows.h file is present (where different names are used). [This was
44        reversed later after testing - see 16 below.]
45    
46    8.  Changed all #include <config.h> to #include "config.h". There were also
47        some further <pcre.h> cases that I changed to "pcre.h".
48    
49    9.  When pcregrep was used with the --colour option, it missed the line ending
50        sequence off the lines that it output.
51    
52    10. It was pointed out to me that arrays of string pointers cause lots of
53        relocations when a shared library is dynamically loaded. A technique of
54        using a single long string with a table of offsets can drastically reduce
55        these. I have refactored PCRE in four places to do this. The result is
56        dramatic:
57    
58          Originally:                          290
59          After changing UCP table:            187
60          After changing error message table:   43
61          After changing table of "verbs"       36
62          After changing table of Posix names   22
63    
64        Thanks to the folks working on Gregex for glib for this insight.
65    
66    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
67        unicode-properties was also set.
68    
69    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
70    
71    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
72        checked only for CRLF.
73    
74    14. Added casts to pcretest.c to avoid compiler warnings.
75    
76    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
77    
78    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
79        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
80        entirely. This removes changes made in 7 above.
81    
82    17. The CMake files have been updated, and there is now more information about
83        building with CMake in the NON-UNIX-USE document.
84    
85    
86    Version 7.3 28-Aug-07
87  ---------------------  ---------------------
88    
89   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 9  Version 7.3 05-Jul-07 Line 91  Version 7.3 05-Jul-07
91      brackets there is not right, since it causes compilers to look for an      brackets there is not right, since it causes compilers to look for an
92      installed pcre.h, not the version that is in the source that is being      installed pcre.h, not the version that is in the source that is being
93      compiled (which of course may be different). I have changed it back to:      compiled (which of course may be different). I have changed it back to:
94    
95        #include "pcre.h"        #include "pcre.h"
   
     I have a vague recollection that the change was concerned with compiling in  
     different directories, but in the new build system, that is taken care of  
     by the VPATH setting the Makefile.  
96    
97        I have a vague recollection that the change was concerned with compiling in
98        different directories, but in the new build system, that is taken care of
99        by the VPATH setting the Makefile.
100    
101     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
102        when the subject happened to end in the byte 0x85 (e.g. if the last
103        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
104        characters but of course it shouldn't be taken as a newline when it is part
105        of another character. The bug was that, for an unlimited repeat of . in
106        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
107        characters when looking for a newline.
108    
109     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
110    
111     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
112        in debug output.
113    
114     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
115        long printing in the pcrecpp unittest when running under MinGW.
116    
117     6. ESC_K was left out of the EBCDIC table.
118    
119     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
120        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
121        limit also applies to "virtual nesting" when a pattern is recursive, and in
122        this case 1000 isn't so big. I have been able to remove this limit at the
123        expense of backing off one optimization in certain circumstances. Normally,
124        when pcre_exec() would call its internal match() function recursively and
125        immediately return the result unconditionally, it uses a "tail recursion"
126        feature to save stack. However, when a subpattern that can match an empty
127        string has an unlimited repetition quantifier, it no longer makes this
128        optimization. That gives it a stack frame in which to save the data for
129        checking that an empty string has been matched. Previously this was taken
130        from the 1000-entry workspace that had been reserved. So now there is no
131        explicit limit, but more stack is used.
132    
133     8. Applied Daniel's patches to solve problems with the import/export magic
134        syntax that is required for Windows, and which was going wrong for the
135        pcreposix and pcrecpp parts of the library. These were overlooked when this
136        problem was solved for the main library.
137    
138     9. There were some crude static tests to avoid integer overflow when computing
139        the size of patterns that contain repeated groups with explicit upper
140        limits. As the maximum quantifier is 65535, the maximum group length was
141        set at 30,000 so that the product of these two numbers did not overflow a
142        32-bit integer. However, it turns out that people want to use groups that
143        are longer than 30,000 bytes (though not repeat them that many times).
144        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
145        made it possible to implement the integer overflow checks in a much more
146        dynamic way, which I have now done. The artificial limitation on group
147        length has been removed - we now have only the limit on the total length of
148        the compiled pattern, which depends on the LINK_SIZE setting.
149    
150    10. Fixed a bug in the documentation for get/copy named substring when
151        duplicate names are permitted. If none of the named substrings are set, the
152        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
153        empty string.
154    
155    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
156        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
157        because the ] is interpreted as the first data character and the
158        terminating ] is not found. PCRE has been made compatible with Perl in this
159        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
160        cause memory overwriting.
161    
162    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
163        string has been matched (to stop an infinite loop). It was not recognizing
164        a conditional subpattern that could match an empty string if that
165        subpattern was within another subpattern. For example, it looped when
166        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
167        condition was not nested. This bug has been fixed.
168    
169    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
170        past the start of the subject in the presence of bytes with the top bit
171        set, for example "\x8aBCD".
172    
173    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
174        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
175    
176    14. Optimized (?!) to (*FAIL).
177    
178    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
179        This restricts code points to be within the range 0 to 0x10FFFF, excluding
180        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
181        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
182        does: it's just the validity check that is more restrictive.
183    
184    16. Inserted checks for integer overflows during escape sequence (backslash)
185        processing, and also fixed erroneous offset values for syntax errors during
186        backslash processing.
187    
188    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
189        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
190    
191    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
192        caused an overrun.
193    
194    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
195        something other than just ASCII characters) inside a group that had an
196        unlimited repeat caused a loop at compile time (while checking to see
197        whether the group could match an empty string).
198    
199    20. Debugging a pattern containing \p or \P could cause a crash. For example,
200        [\P{Any}] did so. (Error in the code for printing property names.)
201    
202    21. An orphan \E inside a character class could cause a crash.
203    
204    22. A repeated capturing bracket such as (A)? could cause a wild memory
205        reference during compilation.
206    
207    23. There are several functions in pcre_compile() that scan along a compiled
208        expression for various reasons (e.g. to see if it's fixed length for look
209        behind). There were bugs in these functions when a repeated \p or \P was
210        present in the pattern. These operators have additional parameters compared
211        with \d, etc, and these were not being taken into account when moving along
212        the compiled data. Specifically:
213    
214        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
215            length.
216    
217        (b) An item such as \pL+ within a repeated group could cause crashes or
218            loops.
219    
220        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
221            "reference to non-existent subpattern" error.
222    
223        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
224    
225    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
226        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
227    
228    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
229    
230    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
231        character were causing crashes (broken optimization).
232    
233    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
234        \p or \P) caused a compile-time loop.
235    
236    28. More problems have arisen in unanchored patterns when CRLF is a valid line
237        break. For example, the unstudied pattern [\r\n]A does not match the string
238        "\r\nA" because change 7.0/46 below moves the current point on by two
239        characters after failing to match at the start. However, the pattern \nA
240        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
241        the same is true. There doesn't seem any very clean way out of this, but
242        what I have chosen to do makes the common cases work: PCRE now takes note
243        of whether there can be an explicit match for \r or \n anywhere in the
244        pattern, and if so, 7.0/46 no longer applies. As part of this change,
245        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
246        pattern has explicit CR or LF references.
247    
248    29. Added (*CR) etc for changing newline setting at start of pattern.
249    
250    
251  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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