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revision 192 by ph10, Mon Jul 30 11:23:21 2007 UTC revision 261 by ph10, Fri Sep 21 08:37:48 2007 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-07  Version 7.4 21-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 when the
36        windows.h file is present (where different names are used). [This was
37        reversed later after testing - see 16 below.]
38    
39    8.  Changed all #include <config.h> to #include "config.h". There were also
40        some further <pcre.h> cases that I changed to "pcre.h".
41    
42    9.  When pcregrep was used with the --colour option, it missed the line ending
43        sequence off the lines that it output.
44    
45    10. It was pointed out to me that arrays of string pointers cause lots of
46        relocations when a shared library is dynamically loaded. A technique of
47        using a single long string with a table of offsets can drastically reduce
48        these. I have refactored PCRE in four places to do this. The result is
49        dramatic:
50    
51          Originally:                          290
52          After changing UCP table:            187
53          After changing error message table:   43
54          After changing table of "verbs"       36
55          After changing table of Posix names   22
56    
57        Thanks to the folks working on Gregex for glib for this insight.
58    
59    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
60        unicode-properties was also set.
61    
62    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
63    
64    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
65        checked only for CRLF.
66    
67    14. Added casts to pcretest.c to avoid compiler warnings.
68    
69    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
70    
71    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
72        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
73        entirely. This removes changes made in 7 above.
74    
75    17. The CMake files have been updated, and there is now more information about
76        building with CMake in the NON-UNIX-USE document.
77    
78    
79    Version 7.3 28-Aug-07
80  ---------------------  ---------------------
81    
82   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 84  Version 7.3 05-Jul-07
84      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
85      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
86      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:
87    
88        #include "pcre.h"        #include "pcre.h"
89    
90      I have a vague recollection that the change was concerned with compiling in      I have a vague recollection that the change was concerned with compiling in
91      different directories, but in the new build system, that is taken care of      different directories, but in the new build system, that is taken care of
92      by the VPATH setting the Makefile.      by the VPATH setting the Makefile.
93    
94   2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed   2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
95      when the subject happened to end in the byte 0x85 (e.g. if the last      when the subject happened to end in the byte 0x85 (e.g. if the last
96      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
# Line 23  Version 7.3 05-Jul-07 Line 98  Version 7.3 05-Jul-07
98      of another character. The bug was that, for an unlimited repeat of . in      of another character. The bug was that, for an unlimited repeat of . in
99      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
100      characters when looking for a newline.      characters when looking for a newline.
   
  3. A small performance improvement in the DOTALL UTF-8 mode .* case.  
   
  4. Debugging: adjusted the names of opcodes for different kinds of parentheses  
     in debug output.  
101    
102     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
103    
104     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
105        in debug output.
106    
107     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
108        long printing in the pcrecpp unittest when running under MinGW.
109    
110     6. ESC_K was left out of the EBCDIC table.
111    
112     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
113        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
114        limit also applies to "virtual nesting" when a pattern is recursive, and in
115        this case 1000 isn't so big. I have been able to remove this limit at the
116        expense of backing off one optimization in certain circumstances. Normally,
117        when pcre_exec() would call its internal match() function recursively and
118        immediately return the result unconditionally, it uses a "tail recursion"
119        feature to save stack. However, when a subpattern that can match an empty
120        string has an unlimited repetition quantifier, it no longer makes this
121        optimization. That gives it a stack frame in which to save the data for
122        checking that an empty string has been matched. Previously this was taken
123        from the 1000-entry workspace that had been reserved. So now there is no
124        explicit limit, but more stack is used.
125    
126     8. Applied Daniel's patches to solve problems with the import/export magic
127        syntax that is required for Windows, and which was going wrong for the
128        pcreposix and pcrecpp parts of the library. These were overlooked when this
129        problem was solved for the main library.
130    
131     9. There were some crude static tests to avoid integer overflow when computing
132        the size of patterns that contain repeated groups with explicit upper
133        limits. As the maximum quantifier is 65535, the maximum group length was
134        set at 30,000 so that the product of these two numbers did not overflow a
135        32-bit integer. However, it turns out that people want to use groups that
136        are longer than 30,000 bytes (though not repeat them that many times).
137        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
138        made it possible to implement the integer overflow checks in a much more
139        dynamic way, which I have now done. The artificial limitation on group
140        length has been removed - we now have only the limit on the total length of
141        the compiled pattern, which depends on the LINK_SIZE setting.
142    
143    10. Fixed a bug in the documentation for get/copy named substring when
144        duplicate names are permitted. If none of the named substrings are set, the
145        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
146        empty string.
147    
148    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
149        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
150        because the ] is interpreted as the first data character and the
151        terminating ] is not found. PCRE has been made compatible with Perl in this
152        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
153        cause memory overwriting.
154    
155    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
156        string has been matched (to stop an infinite loop). It was not recognizing
157        a conditional subpattern that could match an empty string if that
158        subpattern was within another subpattern. For example, it looped when
159        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
160        condition was not nested. This bug has been fixed.
161    
162    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
163        past the start of the subject in the presence of bytes with the top bit
164        set, for example "\x8aBCD".
165    
166    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
167        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
168    
169    14. Optimized (?!) to (*FAIL).
170    
171    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
172        This restricts code points to be within the range 0 to 0x10FFFF, excluding
173        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
174        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
175        does: it's just the validity check that is more restrictive.
176    
177    16. Inserted checks for integer overflows during escape sequence (backslash)
178        processing, and also fixed erroneous offset values for syntax errors during
179        backslash processing.
180    
181    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
182        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
183    
184    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
185        caused an overrun.
186    
187    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
188        something other than just ASCII characters) inside a group that had an
189        unlimited repeat caused a loop at compile time (while checking to see
190        whether the group could match an empty string).
191    
192    20. Debugging a pattern containing \p or \P could cause a crash. For example,
193        [\P{Any}] did so. (Error in the code for printing property names.)
194    
195    21. An orphan \E inside a character class could cause a crash.
196    
197    22. A repeated capturing bracket such as (A)? could cause a wild memory
198        reference during compilation.
199    
200    23. There are several functions in pcre_compile() that scan along a compiled
201        expression for various reasons (e.g. to see if it's fixed length for look
202        behind). There were bugs in these functions when a repeated \p or \P was
203        present in the pattern. These operators have additional parameters compared
204        with \d, etc, and these were not being taken into account when moving along
205        the compiled data. Specifically:
206    
207        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
208            length.
209    
210        (b) An item such as \pL+ within a repeated group could cause crashes or
211            loops.
212    
213        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
214            "reference to non-existent subpattern" error.
215    
216        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
217    
218    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
219        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
220    
221    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
222    
223    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
224        character were causing crashes (broken optimization).
225    
226    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
227        \p or \P) caused a compile-time loop.
228    
229    28. More problems have arisen in unanchored patterns when CRLF is a valid line
230        break. For example, the unstudied pattern [\r\n]A does not match the string
231        "\r\nA" because change 7.0/46 below moves the current point on by two
232        characters after failing to match at the start. However, the pattern \nA
233        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
234        the same is true. There doesn't seem any very clean way out of this, but
235        what I have chosen to do makes the common cases work: PCRE now takes note
236        of whether there can be an explicit match for \r or \n anywhere in the
237        pattern, and if so, 7.0/46 no longer applies. As part of this change,
238        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
239        pattern has explicit CR or LF references.
240    
241    29. Added (*CR) etc for changing newline setting at start of pattern.
242    
243    
244  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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