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revision 135 by ph10, Thu Mar 29 09:09:33 2007 UTC revision 277 by ph10, Mon Nov 26 17:03:45 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-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    
70    Version 7.4 21-Sep-07
71    ---------------------
72    
73    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
74        means that a class such as [\s] counted as "explicit reference to CR or
75        LF". That isn't really right - the whole point of the change was to try to
76        help when there was an actual mention of one of the two characters. So now
77        the change happens only if \r or \n (or a literal CR or LF) character is
78        encountered.
79    
80    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
81        of both had grown to the point where there were only 3 bits left.
82        Fortunately, there was spare space in the data structure, and so I have
83        moved the internal flags into a new 16-bit field to free up more option
84        bits.
85    
86    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
87        but did not set the internal JCHANGED flag - either of these is enough to
88        control the way the "get" function works - but the PCRE_INFO_JCHANGED
89        facility is supposed to tell if (?J) was ever used, so now (?J) at the
90        start sets both bits.
91    
92    4.  Added options (at build time, compile time, exec time) to change \R from
93        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
94    
95    5.  doc/pcresyntax.html was missing from the distribution.
96    
97    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
98        compatibility, even though it is no longer used.
99    
100    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
101        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
102        windows.h file is present (where different names are used). [This was
103        reversed later after testing - see 16 below.]
104    
105    8.  Changed all #include <config.h> to #include "config.h". There were also
106        some further <pcre.h> cases that I changed to "pcre.h".
107    
108    9.  When pcregrep was used with the --colour option, it missed the line ending
109        sequence off the lines that it output.
110    
111    10. It was pointed out to me that arrays of string pointers cause lots of
112        relocations when a shared library is dynamically loaded. A technique of
113        using a single long string with a table of offsets can drastically reduce
114        these. I have refactored PCRE in four places to do this. The result is
115        dramatic:
116    
117          Originally:                          290
118          After changing UCP table:            187
119          After changing error message table:   43
120          After changing table of "verbs"       36
121          After changing table of Posix names   22
122    
123        Thanks to the folks working on Gregex for glib for this insight.
124    
125    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
126        unicode-properties was also set.
127    
128    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
129    
130    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
131        checked only for CRLF.
132    
133    14. Added casts to pcretest.c to avoid compiler warnings.
134    
135    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
136    
137    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
138        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
139        entirely. This removes changes made in 7 above.
140    
141    17. The CMake files have been updated, and there is now more information about
142        building with CMake in the NON-UNIX-USE document.
143    
144    
145    Version 7.3 28-Aug-07
146    ---------------------
147    
148     1. In the rejigging of the build system that eventually resulted in 7.1, the
149        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
150        brackets there is not right, since it causes compilers to look for an
151        installed pcre.h, not the version that is in the source that is being
152        compiled (which of course may be different). I have changed it back to:
153    
154          #include "pcre.h"
155    
156        I have a vague recollection that the change was concerned with compiling in
157        different directories, but in the new build system, that is taken care of
158        by the VPATH setting the Makefile.
159    
160     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
161        when the subject happened to end in the byte 0x85 (e.g. if the last
162        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
163        characters but of course it shouldn't be taken as a newline when it is part
164        of another character. The bug was that, for an unlimited repeat of . in
165        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
166        characters when looking for a newline.
167    
168     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
169    
170     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
171        in debug output.
172    
173     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
174        long printing in the pcrecpp unittest when running under MinGW.
175    
176     6. ESC_K was left out of the EBCDIC table.
177    
178     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
179        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
180        limit also applies to "virtual nesting" when a pattern is recursive, and in
181        this case 1000 isn't so big. I have been able to remove this limit at the
182        expense of backing off one optimization in certain circumstances. Normally,
183        when pcre_exec() would call its internal match() function recursively and
184        immediately return the result unconditionally, it uses a "tail recursion"
185        feature to save stack. However, when a subpattern that can match an empty
186        string has an unlimited repetition quantifier, it no longer makes this
187        optimization. That gives it a stack frame in which to save the data for
188        checking that an empty string has been matched. Previously this was taken
189        from the 1000-entry workspace that had been reserved. So now there is no
190        explicit limit, but more stack is used.
191    
192     8. Applied Daniel's patches to solve problems with the import/export magic
193        syntax that is required for Windows, and which was going wrong for the
194        pcreposix and pcrecpp parts of the library. These were overlooked when this
195        problem was solved for the main library.
196    
197     9. There were some crude static tests to avoid integer overflow when computing
198        the size of patterns that contain repeated groups with explicit upper
199        limits. As the maximum quantifier is 65535, the maximum group length was
200        set at 30,000 so that the product of these two numbers did not overflow a
201        32-bit integer. However, it turns out that people want to use groups that
202        are longer than 30,000 bytes (though not repeat them that many times).
203        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
204        made it possible to implement the integer overflow checks in a much more
205        dynamic way, which I have now done. The artificial limitation on group
206        length has been removed - we now have only the limit on the total length of
207        the compiled pattern, which depends on the LINK_SIZE setting.
208    
209    10. Fixed a bug in the documentation for get/copy named substring when
210        duplicate names are permitted. If none of the named substrings are set, the
211        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
212        empty string.
213    
214    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
215        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
216        because the ] is interpreted as the first data character and the
217        terminating ] is not found. PCRE has been made compatible with Perl in this
218        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
219        cause memory overwriting.
220    
221    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
222        string has been matched (to stop an infinite loop). It was not recognizing
223        a conditional subpattern that could match an empty string if that
224        subpattern was within another subpattern. For example, it looped when
225        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
226        condition was not nested. This bug has been fixed.
227    
228    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
229        past the start of the subject in the presence of bytes with the top bit
230        set, for example "\x8aBCD".
231    
232    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
233        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
234    
235    14. Optimized (?!) to (*FAIL).
236    
237    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
238        This restricts code points to be within the range 0 to 0x10FFFF, excluding
239        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
240        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
241        does: it's just the validity check that is more restrictive.
242    
243    16. Inserted checks for integer overflows during escape sequence (backslash)
244        processing, and also fixed erroneous offset values for syntax errors during
245        backslash processing.
246    
247    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
248        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
249    
250    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
251        caused an overrun.
252    
253    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
254        something other than just ASCII characters) inside a group that had an
255        unlimited repeat caused a loop at compile time (while checking to see
256        whether the group could match an empty string).
257    
258    20. Debugging a pattern containing \p or \P could cause a crash. For example,
259        [\P{Any}] did so. (Error in the code for printing property names.)
260    
261    21. An orphan \E inside a character class could cause a crash.
262    
263    22. A repeated capturing bracket such as (A)? could cause a wild memory
264        reference during compilation.
265    
266    23. There are several functions in pcre_compile() that scan along a compiled
267        expression for various reasons (e.g. to see if it's fixed length for look
268        behind). There were bugs in these functions when a repeated \p or \P was
269        present in the pattern. These operators have additional parameters compared
270        with \d, etc, and these were not being taken into account when moving along
271        the compiled data. Specifically:
272    
273        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
274            length.
275    
276        (b) An item such as \pL+ within a repeated group could cause crashes or
277            loops.
278    
279        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
280            "reference to non-existent subpattern" error.
281    
282        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
283    
284    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
285        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
286    
287    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
288    
289    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
290        character were causing crashes (broken optimization).
291    
292    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
293        \p or \P) caused a compile-time loop.
294    
295    28. More problems have arisen in unanchored patterns when CRLF is a valid line
296        break. For example, the unstudied pattern [\r\n]A does not match the string
297        "\r\nA" because change 7.0/46 below moves the current point on by two
298        characters after failing to match at the start. However, the pattern \nA
299        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
300        the same is true. There doesn't seem any very clean way out of this, but
301        what I have chosen to do makes the common cases work: PCRE now takes note
302        of whether there can be an explicit match for \r or \n anywhere in the
303        pattern, and if so, 7.0/46 no longer applies. As part of this change,
304        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
305        pattern has explicit CR or LF references.
306    
307    29. Added (*CR) etc for changing newline setting at start of pattern.
308    
309    
310    Version 7.2 19-Jun-07
311    ---------------------
312    
313     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
314        which is apparently normally available under Windows.
315    
316     2. Re-jig the pcregrep tests with different newline settings in an attempt
317        to make them independent of the local environment's newline setting.
318    
319     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
320    
321     4. Some of the "internals" tests were previously cut out when the link size
322        was not 2, because the output contained actual offsets. The recent new
323        "Z" feature of pcretest means that these can be cut out, making the tests
324        usable with all link sizes.
325    
326     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
327        stack recursion. This gives a massive performance boost under BSD, but just
328        a small improvement under Linux. However, it saves one field in the frame
329        in all cases.
330    
331     6. Added more features from the forthcoming Perl 5.10:
332    
333        (a) (?-n) (where n is a string of digits) is a relative subroutine or
334            recursion call. It refers to the nth most recently opened parentheses.
335    
336        (b) (?+n) is also a relative subroutine call; it refers to the nth next
337            to be opened parentheses.
338    
339        (c) Conditions that refer to capturing parentheses can be specified
340            relatively, for example, (?(-2)... or (?(+3)...
341    
342        (d) \K resets the start of the current match so that everything before
343            is not part of it.
344    
345        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
346    
347        (f) \g{name} is another synonym - part of Perl 5.10's unification of
348            reference syntax.
349    
350        (g) (?| introduces a group in which the numbering of parentheses in each
351            alternative starts with the same number.
352    
353        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
354    
355     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
356        PCRE_INFO_JCHANGED.
357    
358     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
359        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
360        for detecting groups that can match an empty string.
361    
362     9. A pattern with a very large number of alternatives (more than several
363        hundred) was running out of internal workspace during the pre-compile
364        phase, where pcre_compile() figures out how much memory will be needed. A
365        bit of new cunning has reduced the workspace needed for groups with
366        alternatives. The 1000-alternative test pattern now uses 12 bytes of
367        workspace instead of running out of the 4096 that are available.
368    
369    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
370    
371    11. Applied patch from Google to remove an optimization that didn't quite work.
372        The report of the bug said:
373    
374          pcrecpp::RE("a*").FullMatch("aaa") matches, while
375          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
376          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
377    
378    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
379        it matched the wrong number of bytes.
380    
381    
382    Version 7.1 24-Apr-07
383  ---------------------  ---------------------
384    
385   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 127  Version 7.1 12-Mar-07 Line 505  Version 7.1 12-Mar-07
505      in an attempt to make files that differ only in their line terminators      in an attempt to make files that differ only in their line terminators
506      compare equal. This works on Linux.      compare equal. This works on Linux.
507    
508    17. Under certain error circumstances pcregrep might try to free random memory
509        as it exited. This is now fixed, thanks to valgrind.
510    
511    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
512        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
513        was because its rules for how to advance for /g after matching an empty
514        string at the end of a line did not allow for this case. They now check for
515        it specially.
516    
517    20. pcretest is supposed to handle patterns and data of any length, by
518        extending its buffers when necessary. It was getting this wrong when the
519        buffer for a data line had to be extended.
520    
521    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
522        CRLF as a newline sequence.
523    
524    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
525        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
526        I have nevertheless tidied it up.
527    
528    23. Added some casts to kill warnings from HP-UX ia64 compiler.
529    
530    24. Added a man page for pcre-config.
531    
532    
533  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
534  ---------------------  ---------------------

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