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revision 155 by ph10, Tue Apr 24 13:36:11 2007 UTC revision 279 by ph10, Tue Dec 4 20:01:43 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    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    
80    Version 7.4 21-Sep-07
81    ---------------------
82    
83    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
84        means that a class such as [\s] counted as "explicit reference to CR or
85        LF". That isn't really right - the whole point of the change was to try to
86        help when there was an actual mention of one of the two characters. So now
87        the change happens only if \r or \n (or a literal CR or LF) character is
88        encountered.
89    
90    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
91        of both had grown to the point where there were only 3 bits left.
92        Fortunately, there was spare space in the data structure, and so I have
93        moved the internal flags into a new 16-bit field to free up more option
94        bits.
95    
96    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
97        but did not set the internal JCHANGED flag - either of these is enough to
98        control the way the "get" function works - but the PCRE_INFO_JCHANGED
99        facility is supposed to tell if (?J) was ever used, so now (?J) at the
100        start sets both bits.
101    
102    4.  Added options (at build time, compile time, exec time) to change \R from
103        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
104    
105    5.  doc/pcresyntax.html was missing from the distribution.
106    
107    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
108        compatibility, even though it is no longer used.
109    
110    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
111        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
112        windows.h file is present (where different names are used). [This was
113        reversed later after testing - see 16 below.]
114    
115    8.  Changed all #include <config.h> to #include "config.h". There were also
116        some further <pcre.h> cases that I changed to "pcre.h".
117    
118    9.  When pcregrep was used with the --colour option, it missed the line ending
119        sequence off the lines that it output.
120    
121    10. It was pointed out to me that arrays of string pointers cause lots of
122        relocations when a shared library is dynamically loaded. A technique of
123        using a single long string with a table of offsets can drastically reduce
124        these. I have refactored PCRE in four places to do this. The result is
125        dramatic:
126    
127          Originally:                          290
128          After changing UCP table:            187
129          After changing error message table:   43
130          After changing table of "verbs"       36
131          After changing table of Posix names   22
132    
133        Thanks to the folks working on Gregex for glib for this insight.
134    
135    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
136        unicode-properties was also set.
137    
138    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
139    
140    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
141        checked only for CRLF.
142    
143    14. Added casts to pcretest.c to avoid compiler warnings.
144    
145    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
146    
147    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
148        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
149        entirely. This removes changes made in 7 above.
150    
151    17. The CMake files have been updated, and there is now more information about
152        building with CMake in the NON-UNIX-USE document.
153    
154    
155    Version 7.3 28-Aug-07
156    ---------------------
157    
158     1. In the rejigging of the build system that eventually resulted in 7.1, the
159        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
160        brackets there is not right, since it causes compilers to look for an
161        installed pcre.h, not the version that is in the source that is being
162        compiled (which of course may be different). I have changed it back to:
163    
164          #include "pcre.h"
165    
166        I have a vague recollection that the change was concerned with compiling in
167        different directories, but in the new build system, that is taken care of
168        by the VPATH setting the Makefile.
169    
170     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
171        when the subject happened to end in the byte 0x85 (e.g. if the last
172        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
173        characters but of course it shouldn't be taken as a newline when it is part
174        of another character. The bug was that, for an unlimited repeat of . in
175        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
176        characters when looking for a newline.
177    
178     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
179    
180     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
181        in debug output.
182    
183     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
184        long printing in the pcrecpp unittest when running under MinGW.
185    
186     6. ESC_K was left out of the EBCDIC table.
187    
188     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
189        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
190        limit also applies to "virtual nesting" when a pattern is recursive, and in
191        this case 1000 isn't so big. I have been able to remove this limit at the
192        expense of backing off one optimization in certain circumstances. Normally,
193        when pcre_exec() would call its internal match() function recursively and
194        immediately return the result unconditionally, it uses a "tail recursion"
195        feature to save stack. However, when a subpattern that can match an empty
196        string has an unlimited repetition quantifier, it no longer makes this
197        optimization. That gives it a stack frame in which to save the data for
198        checking that an empty string has been matched. Previously this was taken
199        from the 1000-entry workspace that had been reserved. So now there is no
200        explicit limit, but more stack is used.
201    
202     8. Applied Daniel's patches to solve problems with the import/export magic
203        syntax that is required for Windows, and which was going wrong for the
204        pcreposix and pcrecpp parts of the library. These were overlooked when this
205        problem was solved for the main library.
206    
207     9. There were some crude static tests to avoid integer overflow when computing
208        the size of patterns that contain repeated groups with explicit upper
209        limits. As the maximum quantifier is 65535, the maximum group length was
210        set at 30,000 so that the product of these two numbers did not overflow a
211        32-bit integer. However, it turns out that people want to use groups that
212        are longer than 30,000 bytes (though not repeat them that many times).
213        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
214        made it possible to implement the integer overflow checks in a much more
215        dynamic way, which I have now done. The artificial limitation on group
216        length has been removed - we now have only the limit on the total length of
217        the compiled pattern, which depends on the LINK_SIZE setting.
218    
219    10. Fixed a bug in the documentation for get/copy named substring when
220        duplicate names are permitted. If none of the named substrings are set, the
221        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
222        empty string.
223    
224    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
225        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
226        because the ] is interpreted as the first data character and the
227        terminating ] is not found. PCRE has been made compatible with Perl in this
228        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
229        cause memory overwriting.
230    
231    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
232        string has been matched (to stop an infinite loop). It was not recognizing
233        a conditional subpattern that could match an empty string if that
234        subpattern was within another subpattern. For example, it looped when
235        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
236        condition was not nested. This bug has been fixed.
237    
238    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
239        past the start of the subject in the presence of bytes with the top bit
240        set, for example "\x8aBCD".
241    
242    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
243        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
244    
245    14. Optimized (?!) to (*FAIL).
246    
247    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
248        This restricts code points to be within the range 0 to 0x10FFFF, excluding
249        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
250        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
251        does: it's just the validity check that is more restrictive.
252    
253    16. Inserted checks for integer overflows during escape sequence (backslash)
254        processing, and also fixed erroneous offset values for syntax errors during
255        backslash processing.
256    
257    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
258        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
259    
260    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
261        caused an overrun.
262    
263    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
264        something other than just ASCII characters) inside a group that had an
265        unlimited repeat caused a loop at compile time (while checking to see
266        whether the group could match an empty string).
267    
268    20. Debugging a pattern containing \p or \P could cause a crash. For example,
269        [\P{Any}] did so. (Error in the code for printing property names.)
270    
271    21. An orphan \E inside a character class could cause a crash.
272    
273    22. A repeated capturing bracket such as (A)? could cause a wild memory
274        reference during compilation.
275    
276    23. There are several functions in pcre_compile() that scan along a compiled
277        expression for various reasons (e.g. to see if it's fixed length for look
278        behind). There were bugs in these functions when a repeated \p or \P was
279        present in the pattern. These operators have additional parameters compared
280        with \d, etc, and these were not being taken into account when moving along
281        the compiled data. Specifically:
282    
283        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
284            length.
285    
286        (b) An item such as \pL+ within a repeated group could cause crashes or
287            loops.
288    
289        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
290            "reference to non-existent subpattern" error.
291    
292        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
293    
294    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
295        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
296    
297    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
298    
299    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
300        character were causing crashes (broken optimization).
301    
302    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
303        \p or \P) caused a compile-time loop.
304    
305    28. More problems have arisen in unanchored patterns when CRLF is a valid line
306        break. For example, the unstudied pattern [\r\n]A does not match the string
307        "\r\nA" because change 7.0/46 below moves the current point on by two
308        characters after failing to match at the start. However, the pattern \nA
309        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
310        the same is true. There doesn't seem any very clean way out of this, but
311        what I have chosen to do makes the common cases work: PCRE now takes note
312        of whether there can be an explicit match for \r or \n anywhere in the
313        pattern, and if so, 7.0/46 no longer applies. As part of this change,
314        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
315        pattern has explicit CR or LF references.
316    
317    29. Added (*CR) etc for changing newline setting at start of pattern.
318    
319    
320    Version 7.2 19-Jun-07
321    ---------------------
322    
323     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
324        which is apparently normally available under Windows.
325    
326     2. Re-jig the pcregrep tests with different newline settings in an attempt
327        to make them independent of the local environment's newline setting.
328    
329     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
330    
331     4. Some of the "internals" tests were previously cut out when the link size
332        was not 2, because the output contained actual offsets. The recent new
333        "Z" feature of pcretest means that these can be cut out, making the tests
334        usable with all link sizes.
335    
336     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
337        stack recursion. This gives a massive performance boost under BSD, but just
338        a small improvement under Linux. However, it saves one field in the frame
339        in all cases.
340    
341     6. Added more features from the forthcoming Perl 5.10:
342    
343        (a) (?-n) (where n is a string of digits) is a relative subroutine or
344            recursion call. It refers to the nth most recently opened parentheses.
345    
346        (b) (?+n) is also a relative subroutine call; it refers to the nth next
347            to be opened parentheses.
348    
349        (c) Conditions that refer to capturing parentheses can be specified
350            relatively, for example, (?(-2)... or (?(+3)...
351    
352        (d) \K resets the start of the current match so that everything before
353            is not part of it.
354    
355        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
356    
357        (f) \g{name} is another synonym - part of Perl 5.10's unification of
358            reference syntax.
359    
360        (g) (?| introduces a group in which the numbering of parentheses in each
361            alternative starts with the same number.
362    
363        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
364    
365     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
366        PCRE_INFO_JCHANGED.
367    
368     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
369        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
370        for detecting groups that can match an empty string.
371    
372     9. A pattern with a very large number of alternatives (more than several
373        hundred) was running out of internal workspace during the pre-compile
374        phase, where pcre_compile() figures out how much memory will be needed. A
375        bit of new cunning has reduced the workspace needed for groups with
376        alternatives. The 1000-alternative test pattern now uses 12 bytes of
377        workspace instead of running out of the 4096 that are available.
378    
379    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
380    
381    11. Applied patch from Google to remove an optimization that didn't quite work.
382        The report of the bug said:
383    
384          pcrecpp::RE("a*").FullMatch("aaa") matches, while
385          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
386          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
387    
388    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
389        it matched the wrong number of bytes.
390    
391    
392  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
393  ---------------------  ---------------------
394    

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