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revision 193 by ph10, Mon Jul 30 11:34:18 2007 UTC revision 289 by ph10, Sun Dec 23 12:17:20 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 23-Dec-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. Added --file-offsets and --line-offsets to pcregrep.
80    
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
85    
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
89    
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
95    
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97    
98    19. Added --enable-pcretest-libreadline.
99    
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I have removed one of the increments.
103    
104    
105    Version 7.4 21-Sep-07
106    ---------------------
107    
108    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
109        means that a class such as [\s] counted as "explicit reference to CR or
110        LF". That isn't really right - the whole point of the change was to try to
111        help when there was an actual mention of one of the two characters. So now
112        the change happens only if \r or \n (or a literal CR or LF) character is
113        encountered.
114    
115    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
116        of both had grown to the point where there were only 3 bits left.
117        Fortunately, there was spare space in the data structure, and so I have
118        moved the internal flags into a new 16-bit field to free up more option
119        bits.
120    
121    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
122        but did not set the internal JCHANGED flag - either of these is enough to
123        control the way the "get" function works - but the PCRE_INFO_JCHANGED
124        facility is supposed to tell if (?J) was ever used, so now (?J) at the
125        start sets both bits.
126    
127    4.  Added options (at build time, compile time, exec time) to change \R from
128        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
129    
130    5.  doc/pcresyntax.html was missing from the distribution.
131    
132    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
133        compatibility, even though it is no longer used.
134    
135    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
136        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
137        windows.h file is present (where different names are used). [This was
138        reversed later after testing - see 16 below.]
139    
140    8.  Changed all #include <config.h> to #include "config.h". There were also
141        some further <pcre.h> cases that I changed to "pcre.h".
142    
143    9.  When pcregrep was used with the --colour option, it missed the line ending
144        sequence off the lines that it output.
145    
146    10. It was pointed out to me that arrays of string pointers cause lots of
147        relocations when a shared library is dynamically loaded. A technique of
148        using a single long string with a table of offsets can drastically reduce
149        these. I have refactored PCRE in four places to do this. The result is
150        dramatic:
151    
152          Originally:                          290
153          After changing UCP table:            187
154          After changing error message table:   43
155          After changing table of "verbs"       36
156          After changing table of Posix names   22
157    
158        Thanks to the folks working on Gregex for glib for this insight.
159    
160    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
161        unicode-properties was also set.
162    
163    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
164    
165    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
166        checked only for CRLF.
167    
168    14. Added casts to pcretest.c to avoid compiler warnings.
169    
170    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
171    
172    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
173        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
174        entirely. This removes changes made in 7 above.
175    
176    17. The CMake files have been updated, and there is now more information about
177        building with CMake in the NON-UNIX-USE document.
178    
179    
180    Version 7.3 28-Aug-07
181  ---------------------  ---------------------
182    
183   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 185  Version 7.3 05-Jul-07
185      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
186      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
187      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:
188    
189        #include "pcre.h"        #include "pcre.h"
190    
191      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
192      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
193      by the VPATH setting the Makefile.      by the VPATH setting the Makefile.
194    
195   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
196      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
197      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 199  Version 7.3 05-Jul-07
199      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
200      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
201      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.  
202    
203     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
204    
205     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
206        in debug output.
207    
208     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
209        long printing in the pcrecpp unittest when running under MinGW.
210    
211     6. ESC_K was left out of the EBCDIC table.
212    
213     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
214        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
215        limit also applies to "virtual nesting" when a pattern is recursive, and in
216        this case 1000 isn't so big. I have been able to remove this limit at the
217        expense of backing off one optimization in certain circumstances. Normally,
218        when pcre_exec() would call its internal match() function recursively and
219        immediately return the result unconditionally, it uses a "tail recursion"
220        feature to save stack. However, when a subpattern that can match an empty
221        string has an unlimited repetition quantifier, it no longer makes this
222        optimization. That gives it a stack frame in which to save the data for
223        checking that an empty string has been matched. Previously this was taken
224        from the 1000-entry workspace that had been reserved. So now there is no
225        explicit limit, but more stack is used.
226    
227     8. Applied Daniel's patches to solve problems with the import/export magic
228        syntax that is required for Windows, and which was going wrong for the
229        pcreposix and pcrecpp parts of the library. These were overlooked when this
230        problem was solved for the main library.
231    
232     9. There were some crude static tests to avoid integer overflow when computing
233        the size of patterns that contain repeated groups with explicit upper
234        limits. As the maximum quantifier is 65535, the maximum group length was
235        set at 30,000 so that the product of these two numbers did not overflow a
236        32-bit integer. However, it turns out that people want to use groups that
237        are longer than 30,000 bytes (though not repeat them that many times).
238        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
239        made it possible to implement the integer overflow checks in a much more
240        dynamic way, which I have now done. The artificial limitation on group
241        length has been removed - we now have only the limit on the total length of
242        the compiled pattern, which depends on the LINK_SIZE setting.
243    
244    10. Fixed a bug in the documentation for get/copy named substring when
245        duplicate names are permitted. If none of the named substrings are set, the
246        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
247        empty string.
248    
249    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
250        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
251        because the ] is interpreted as the first data character and the
252        terminating ] is not found. PCRE has been made compatible with Perl in this
253        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
254        cause memory overwriting.
255    
256    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
257        string has been matched (to stop an infinite loop). It was not recognizing
258        a conditional subpattern that could match an empty string if that
259        subpattern was within another subpattern. For example, it looped when
260        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
261        condition was not nested. This bug has been fixed.
262    
263    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
264        past the start of the subject in the presence of bytes with the top bit
265        set, for example "\x8aBCD".
266    
267    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
268        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
269    
270    14. Optimized (?!) to (*FAIL).
271    
272    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
273        This restricts code points to be within the range 0 to 0x10FFFF, excluding
274        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
275        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
276        does: it's just the validity check that is more restrictive.
277    
278    16. Inserted checks for integer overflows during escape sequence (backslash)
279        processing, and also fixed erroneous offset values for syntax errors during
280        backslash processing.
281    
282    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
283        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
284    
285    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
286        caused an overrun.
287    
288    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
289        something other than just ASCII characters) inside a group that had an
290        unlimited repeat caused a loop at compile time (while checking to see
291        whether the group could match an empty string).
292    
293    20. Debugging a pattern containing \p or \P could cause a crash. For example,
294        [\P{Any}] did so. (Error in the code for printing property names.)
295    
296    21. An orphan \E inside a character class could cause a crash.
297    
298    22. A repeated capturing bracket such as (A)? could cause a wild memory
299        reference during compilation.
300    
301    23. There are several functions in pcre_compile() that scan along a compiled
302        expression for various reasons (e.g. to see if it's fixed length for look
303        behind). There were bugs in these functions when a repeated \p or \P was
304        present in the pattern. These operators have additional parameters compared
305        with \d, etc, and these were not being taken into account when moving along
306        the compiled data. Specifically:
307    
308        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
309            length.
310    
311        (b) An item such as \pL+ within a repeated group could cause crashes or
312            loops.
313    
314        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
315            "reference to non-existent subpattern" error.
316    
317        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
318    
319    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
320        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
321    
322    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
323    
324    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
325        character were causing crashes (broken optimization).
326    
327    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
328        \p or \P) caused a compile-time loop.
329    
330    28. More problems have arisen in unanchored patterns when CRLF is a valid line
331        break. For example, the unstudied pattern [\r\n]A does not match the string
332        "\r\nA" because change 7.0/46 below moves the current point on by two
333        characters after failing to match at the start. However, the pattern \nA
334        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
335        the same is true. There doesn't seem any very clean way out of this, but
336        what I have chosen to do makes the common cases work: PCRE now takes note
337        of whether there can be an explicit match for \r or \n anywhere in the
338        pattern, and if so, 7.0/46 no longer applies. As part of this change,
339        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
340        pattern has explicit CR or LF references.
341    
342    29. Added (*CR) etc for changing newline setting at start of pattern.
343    
344    
345  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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