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revision 210 by ph10, Wed Aug 8 14:24:50 2007 UTC revision 231 by ph10, Tue Sep 11 11:15:33 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-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    
30    Version 7.3 28-Aug-07
31  ---------------------  ---------------------
32    
33   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 87  Version 7.3 05-Jul-07 Line 113  Version 7.3 05-Jul-07
113  12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack  12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
114      past the start of the subject in the presence of bytes with the top bit      past the start of the subject in the presence of bytes with the top bit
115      set, for example "\x8aBCD".      set, for example "\x8aBCD".
116    
117  13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),  13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
118      (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).      (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
119    
120  14. Optimized (?!) to (*FAIL).  14. Optimized (?!) to (*FAIL).
121    
122    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
123        This restricts code points to be within the range 0 to 0x10FFFF, excluding
124        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
125        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
126        does: it's just the validity check that is more restrictive.
127    
128    16. Inserted checks for integer overflows during escape sequence (backslash)
129        processing, and also fixed erroneous offset values for syntax errors during
130        backslash processing.
131    
132    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
133        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
134    
135    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
136        caused an overrun.
137    
138    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
139        something other than just ASCII characters) inside a group that had an
140        unlimited repeat caused a loop at compile time (while checking to see
141        whether the group could match an empty string).
142    
143    20. Debugging a pattern containing \p or \P could cause a crash. For example,
144        [\P{Any}] did so. (Error in the code for printing property names.)
145    
146    21. An orphan \E inside a character class could cause a crash.
147    
148    22. A repeated capturing bracket such as (A)? could cause a wild memory
149        reference during compilation.
150    
151    23. There are several functions in pcre_compile() that scan along a compiled
152        expression for various reasons (e.g. to see if it's fixed length for look
153        behind). There were bugs in these functions when a repeated \p or \P was
154        present in the pattern. These operators have additional parameters compared
155        with \d, etc, and these were not being taken into account when moving along
156        the compiled data. Specifically:
157    
158        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
159            length.
160    
161        (b) An item such as \pL+ within a repeated group could cause crashes or
162            loops.
163    
164        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
165            "reference to non-existent subpattern" error.
166    
167        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
168    
169    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
170        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
171    
172    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
173    
174    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
175        character were causing crashes (broken optimization).
176    
177    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
178        \p or \P) caused a compile-time loop.
179    
180    28. More problems have arisen in unanchored patterns when CRLF is a valid line
181        break. For example, the unstudied pattern [\r\n]A does not match the string
182        "\r\nA" because change 7.0/46 below moves the current point on by two
183        characters after failing to match at the start. However, the pattern \nA
184        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
185        the same is true. There doesn't seem any very clean way out of this, but
186        what I have chosen to do makes the common cases work: PCRE now takes note
187        of whether there can be an explicit match for \r or \n anywhere in the
188        pattern, and if so, 7.0/46 no longer applies. As part of this change,
189        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
190        pattern has explicit CR or LF references.
191    
192    29. Added (*CR) etc for changing newline setting at start of pattern.
193    
194    
195  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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