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revision 195 by ph10, Mon Jul 30 13:23:28 2007 UTC revision 282 by ph10, Fri Dec 7 19:32:32 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    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). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. The pattern (?=something)(?R) was not being diagnosed as a potentially
80        infinitely looping recursion. The bug was that positive lookaheads were not
81        being skipped when checking for a possible empty match (negative lookaheads
82        and both kinds of lookbehind were skipped).
83    
84    
85    Version 7.4 21-Sep-07
86    ---------------------
87    
88    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
89        means that a class such as [\s] counted as "explicit reference to CR or
90        LF". That isn't really right - the whole point of the change was to try to
91        help when there was an actual mention of one of the two characters. So now
92        the change happens only if \r or \n (or a literal CR or LF) character is
93        encountered.
94    
95    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
96        of both had grown to the point where there were only 3 bits left.
97        Fortunately, there was spare space in the data structure, and so I have
98        moved the internal flags into a new 16-bit field to free up more option
99        bits.
100    
101    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
102        but did not set the internal JCHANGED flag - either of these is enough to
103        control the way the "get" function works - but the PCRE_INFO_JCHANGED
104        facility is supposed to tell if (?J) was ever used, so now (?J) at the
105        start sets both bits.
106    
107    4.  Added options (at build time, compile time, exec time) to change \R from
108        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
109    
110    5.  doc/pcresyntax.html was missing from the distribution.
111    
112    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
113        compatibility, even though it is no longer used.
114    
115    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
116        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
117        windows.h file is present (where different names are used). [This was
118        reversed later after testing - see 16 below.]
119    
120    8.  Changed all #include <config.h> to #include "config.h". There were also
121        some further <pcre.h> cases that I changed to "pcre.h".
122    
123    9.  When pcregrep was used with the --colour option, it missed the line ending
124        sequence off the lines that it output.
125    
126    10. It was pointed out to me that arrays of string pointers cause lots of
127        relocations when a shared library is dynamically loaded. A technique of
128        using a single long string with a table of offsets can drastically reduce
129        these. I have refactored PCRE in four places to do this. The result is
130        dramatic:
131    
132          Originally:                          290
133          After changing UCP table:            187
134          After changing error message table:   43
135          After changing table of "verbs"       36
136          After changing table of Posix names   22
137    
138        Thanks to the folks working on Gregex for glib for this insight.
139    
140    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
141        unicode-properties was also set.
142    
143    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
144    
145    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
146        checked only for CRLF.
147    
148    14. Added casts to pcretest.c to avoid compiler warnings.
149    
150    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
151    
152    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
153        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
154        entirely. This removes changes made in 7 above.
155    
156    17. The CMake files have been updated, and there is now more information about
157        building with CMake in the NON-UNIX-USE document.
158    
159    
160    Version 7.3 28-Aug-07
161  ---------------------  ---------------------
162    
163   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 165  Version 7.3 05-Jul-07
165      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
166      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
167      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:
168    
169        #include "pcre.h"        #include "pcre.h"
170    
171      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
172      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
173      by the VPATH setting the Makefile.      by the VPATH setting the Makefile.
174    
175   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
176      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
177      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 179  Version 7.3 05-Jul-07
179      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
180      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
181      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.  
   
  5. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp  
     unittest when running under MinGW.  
   
  6. ESC_K was left out of the EBCDIC table.  
182    
183     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
184    
185     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
186        in debug output.
187    
188     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
189        long printing in the pcrecpp unittest when running under MinGW.
190    
191     6. ESC_K was left out of the EBCDIC table.
192    
193     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
194        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
195        limit also applies to "virtual nesting" when a pattern is recursive, and in
196        this case 1000 isn't so big. I have been able to remove this limit at the
197        expense of backing off one optimization in certain circumstances. Normally,
198        when pcre_exec() would call its internal match() function recursively and
199        immediately return the result unconditionally, it uses a "tail recursion"
200        feature to save stack. However, when a subpattern that can match an empty
201        string has an unlimited repetition quantifier, it no longer makes this
202        optimization. That gives it a stack frame in which to save the data for
203        checking that an empty string has been matched. Previously this was taken
204        from the 1000-entry workspace that had been reserved. So now there is no
205        explicit limit, but more stack is used.
206    
207     8. Applied Daniel's patches to solve problems with the import/export magic
208        syntax that is required for Windows, and which was going wrong for the
209        pcreposix and pcrecpp parts of the library. These were overlooked when this
210        problem was solved for the main library.
211    
212     9. There were some crude static tests to avoid integer overflow when computing
213        the size of patterns that contain repeated groups with explicit upper
214        limits. As the maximum quantifier is 65535, the maximum group length was
215        set at 30,000 so that the product of these two numbers did not overflow a
216        32-bit integer. However, it turns out that people want to use groups that
217        are longer than 30,000 bytes (though not repeat them that many times).
218        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
219        made it possible to implement the integer overflow checks in a much more
220        dynamic way, which I have now done. The artificial limitation on group
221        length has been removed - we now have only the limit on the total length of
222        the compiled pattern, which depends on the LINK_SIZE setting.
223    
224    10. Fixed a bug in the documentation for get/copy named substring when
225        duplicate names are permitted. If none of the named substrings are set, the
226        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
227        empty string.
228    
229    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
230        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
231        because the ] is interpreted as the first data character and the
232        terminating ] is not found. PCRE has been made compatible with Perl in this
233        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
234        cause memory overwriting.
235    
236    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
237        string has been matched (to stop an infinite loop). It was not recognizing
238        a conditional subpattern that could match an empty string if that
239        subpattern was within another subpattern. For example, it looped when
240        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
241        condition was not nested. This bug has been fixed.
242    
243    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
244        past the start of the subject in the presence of bytes with the top bit
245        set, for example "\x8aBCD".
246    
247    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
248        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
249    
250    14. Optimized (?!) to (*FAIL).
251    
252    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
253        This restricts code points to be within the range 0 to 0x10FFFF, excluding
254        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
255        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
256        does: it's just the validity check that is more restrictive.
257    
258    16. Inserted checks for integer overflows during escape sequence (backslash)
259        processing, and also fixed erroneous offset values for syntax errors during
260        backslash processing.
261    
262    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
263        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
264    
265    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
266        caused an overrun.
267    
268    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
269        something other than just ASCII characters) inside a group that had an
270        unlimited repeat caused a loop at compile time (while checking to see
271        whether the group could match an empty string).
272    
273    20. Debugging a pattern containing \p or \P could cause a crash. For example,
274        [\P{Any}] did so. (Error in the code for printing property names.)
275    
276    21. An orphan \E inside a character class could cause a crash.
277    
278    22. A repeated capturing bracket such as (A)? could cause a wild memory
279        reference during compilation.
280    
281    23. There are several functions in pcre_compile() that scan along a compiled
282        expression for various reasons (e.g. to see if it's fixed length for look
283        behind). There were bugs in these functions when a repeated \p or \P was
284        present in the pattern. These operators have additional parameters compared
285        with \d, etc, and these were not being taken into account when moving along
286        the compiled data. Specifically:
287    
288        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
289            length.
290    
291        (b) An item such as \pL+ within a repeated group could cause crashes or
292            loops.
293    
294        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
295            "reference to non-existent subpattern" error.
296    
297        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
298    
299    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
300        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
301    
302    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
303    
304    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
305        character were causing crashes (broken optimization).
306    
307    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
308        \p or \P) caused a compile-time loop.
309    
310    28. More problems have arisen in unanchored patterns when CRLF is a valid line
311        break. For example, the unstudied pattern [\r\n]A does not match the string
312        "\r\nA" because change 7.0/46 below moves the current point on by two
313        characters after failing to match at the start. However, the pattern \nA
314        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
315        the same is true. There doesn't seem any very clean way out of this, but
316        what I have chosen to do makes the common cases work: PCRE now takes note
317        of whether there can be an explicit match for \r or \n anywhere in the
318        pattern, and if so, 7.0/46 no longer applies. As part of this change,
319        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
320        pattern has explicit CR or LF references.
321    
322    29. Added (*CR) etc for changing newline setting at start of pattern.
323    
324    
325  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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