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revision 155 by ph10, Tue Apr 24 13:36:11 2007 UTC revision 275 by ph10, Wed Nov 21 15:35:09 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 12-Nov-07
5    ---------------------
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."
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.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
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.
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).
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.
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.
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
46    Version 7.4 21-Sep-07
47    ---------------------
49    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
50        means that a class such as [\s] counted as "explicit reference to CR or
51        LF". That isn't really right - the whole point of the change was to try to
52        help when there was an actual mention of one of the two characters. So now
53        the change happens only if \r or \n (or a literal CR or LF) character is
54        encountered.
56    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
57        of both had grown to the point where there were only 3 bits left.
58        Fortunately, there was spare space in the data structure, and so I have
59        moved the internal flags into a new 16-bit field to free up more option
60        bits.
62    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
63        but did not set the internal JCHANGED flag - either of these is enough to
64        control the way the "get" function works - but the PCRE_INFO_JCHANGED
65        facility is supposed to tell if (?J) was ever used, so now (?J) at the
66        start sets both bits.
68    4.  Added options (at build time, compile time, exec time) to change \R from
69        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
71    5.  doc/pcresyntax.html was missing from the distribution.
73    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
74        compatibility, even though it is no longer used.
76    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
77        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
78        windows.h file is present (where different names are used). [This was
79        reversed later after testing - see 16 below.]
81    8.  Changed all #include <config.h> to #include "config.h". There were also
82        some further <pcre.h> cases that I changed to "pcre.h".
84    9.  When pcregrep was used with the --colour option, it missed the line ending
85        sequence off the lines that it output.
87    10. It was pointed out to me that arrays of string pointers cause lots of
88        relocations when a shared library is dynamically loaded. A technique of
89        using a single long string with a table of offsets can drastically reduce
90        these. I have refactored PCRE in four places to do this. The result is
91        dramatic:
93          Originally:                          290
94          After changing UCP table:            187
95          After changing error message table:   43
96          After changing table of "verbs"       36
97          After changing table of Posix names   22
99        Thanks to the folks working on Gregex for glib for this insight.
101    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
102        unicode-properties was also set.
104    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
106    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
107        checked only for CRLF.
109    14. Added casts to pcretest.c to avoid compiler warnings.
111    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
113    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
114        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
115        entirely. This removes changes made in 7 above.
117    17. The CMake files have been updated, and there is now more information about
118        building with CMake in the NON-UNIX-USE document.
121    Version 7.3 28-Aug-07
122    ---------------------
124     1. In the rejigging of the build system that eventually resulted in 7.1, the
125        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
126        brackets there is not right, since it causes compilers to look for an
127        installed pcre.h, not the version that is in the source that is being
128        compiled (which of course may be different). I have changed it back to:
130          #include "pcre.h"
132        I have a vague recollection that the change was concerned with compiling in
133        different directories, but in the new build system, that is taken care of
134        by the VPATH setting the Makefile.
136     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
137        when the subject happened to end in the byte 0x85 (e.g. if the last
138        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
139        characters but of course it shouldn't be taken as a newline when it is part
140        of another character. The bug was that, for an unlimited repeat of . in
141        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
142        characters when looking for a newline.
144     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
146     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
147        in debug output.
149     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
150        long printing in the pcrecpp unittest when running under MinGW.
152     6. ESC_K was left out of the EBCDIC table.
154     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
155        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
156        limit also applies to "virtual nesting" when a pattern is recursive, and in
157        this case 1000 isn't so big. I have been able to remove this limit at the
158        expense of backing off one optimization in certain circumstances. Normally,
159        when pcre_exec() would call its internal match() function recursively and
160        immediately return the result unconditionally, it uses a "tail recursion"
161        feature to save stack. However, when a subpattern that can match an empty
162        string has an unlimited repetition quantifier, it no longer makes this
163        optimization. That gives it a stack frame in which to save the data for
164        checking that an empty string has been matched. Previously this was taken
165        from the 1000-entry workspace that had been reserved. So now there is no
166        explicit limit, but more stack is used.
168     8. Applied Daniel's patches to solve problems with the import/export magic
169        syntax that is required for Windows, and which was going wrong for the
170        pcreposix and pcrecpp parts of the library. These were overlooked when this
171        problem was solved for the main library.
173     9. There were some crude static tests to avoid integer overflow when computing
174        the size of patterns that contain repeated groups with explicit upper
175        limits. As the maximum quantifier is 65535, the maximum group length was
176        set at 30,000 so that the product of these two numbers did not overflow a
177        32-bit integer. However, it turns out that people want to use groups that
178        are longer than 30,000 bytes (though not repeat them that many times).
179        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
180        made it possible to implement the integer overflow checks in a much more
181        dynamic way, which I have now done. The artificial limitation on group
182        length has been removed - we now have only the limit on the total length of
183        the compiled pattern, which depends on the LINK_SIZE setting.
185    10. Fixed a bug in the documentation for get/copy named substring when
186        duplicate names are permitted. If none of the named substrings are set, the
187        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
188        empty string.
190    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
191        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
192        because the ] is interpreted as the first data character and the
193        terminating ] is not found. PCRE has been made compatible with Perl in this
194        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
195        cause memory overwriting.
197    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
198        string has been matched (to stop an infinite loop). It was not recognizing
199        a conditional subpattern that could match an empty string if that
200        subpattern was within another subpattern. For example, it looped when
201        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
202        condition was not nested. This bug has been fixed.
204    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
205        past the start of the subject in the presence of bytes with the top bit
206        set, for example "\x8aBCD".
208    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
209        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
211    14. Optimized (?!) to (*FAIL).
213    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
214        This restricts code points to be within the range 0 to 0x10FFFF, excluding
215        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
216        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
217        does: it's just the validity check that is more restrictive.
219    16. Inserted checks for integer overflows during escape sequence (backslash)
220        processing, and also fixed erroneous offset values for syntax errors during
221        backslash processing.
223    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
224        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
226    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
227        caused an overrun.
229    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
230        something other than just ASCII characters) inside a group that had an
231        unlimited repeat caused a loop at compile time (while checking to see
232        whether the group could match an empty string).
234    20. Debugging a pattern containing \p or \P could cause a crash. For example,
235        [\P{Any}] did so. (Error in the code for printing property names.)
237    21. An orphan \E inside a character class could cause a crash.
239    22. A repeated capturing bracket such as (A)? could cause a wild memory
240        reference during compilation.
242    23. There are several functions in pcre_compile() that scan along a compiled
243        expression for various reasons (e.g. to see if it's fixed length for look
244        behind). There were bugs in these functions when a repeated \p or \P was
245        present in the pattern. These operators have additional parameters compared
246        with \d, etc, and these were not being taken into account when moving along
247        the compiled data. Specifically:
249        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
250            length.
252        (b) An item such as \pL+ within a repeated group could cause crashes or
253            loops.
255        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
256            "reference to non-existent subpattern" error.
258        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
260    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
261        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
263    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
265    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
266        character were causing crashes (broken optimization).
268    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
269        \p or \P) caused a compile-time loop.
271    28. More problems have arisen in unanchored patterns when CRLF is a valid line
272        break. For example, the unstudied pattern [\r\n]A does not match the string
273        "\r\nA" because change 7.0/46 below moves the current point on by two
274        characters after failing to match at the start. However, the pattern \nA
275        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
276        the same is true. There doesn't seem any very clean way out of this, but
277        what I have chosen to do makes the common cases work: PCRE now takes note
278        of whether there can be an explicit match for \r or \n anywhere in the
279        pattern, and if so, 7.0/46 no longer applies. As part of this change,
280        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
281        pattern has explicit CR or LF references.
283    29. Added (*CR) etc for changing newline setting at start of pattern.
286    Version 7.2 19-Jun-07
287    ---------------------
289     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
290        which is apparently normally available under Windows.
292     2. Re-jig the pcregrep tests with different newline settings in an attempt
293        to make them independent of the local environment's newline setting.
295     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
297     4. Some of the "internals" tests were previously cut out when the link size
298        was not 2, because the output contained actual offsets. The recent new
299        "Z" feature of pcretest means that these can be cut out, making the tests
300        usable with all link sizes.
302     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
303        stack recursion. This gives a massive performance boost under BSD, but just
304        a small improvement under Linux. However, it saves one field in the frame
305        in all cases.
307     6. Added more features from the forthcoming Perl 5.10:
309        (a) (?-n) (where n is a string of digits) is a relative subroutine or
310            recursion call. It refers to the nth most recently opened parentheses.
312        (b) (?+n) is also a relative subroutine call; it refers to the nth next
313            to be opened parentheses.
315        (c) Conditions that refer to capturing parentheses can be specified
316            relatively, for example, (?(-2)... or (?(+3)...
318        (d) \K resets the start of the current match so that everything before
319            is not part of it.
321        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
323        (f) \g{name} is another synonym - part of Perl 5.10's unification of
324            reference syntax.
326        (g) (?| introduces a group in which the numbering of parentheses in each
327            alternative starts with the same number.
329        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
331     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
334     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
335        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
336        for detecting groups that can match an empty string.
338     9. A pattern with a very large number of alternatives (more than several
339        hundred) was running out of internal workspace during the pre-compile
340        phase, where pcre_compile() figures out how much memory will be needed. A
341        bit of new cunning has reduced the workspace needed for groups with
342        alternatives. The 1000-alternative test pattern now uses 12 bytes of
343        workspace instead of running out of the 4096 that are available.
345    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
347    11. Applied patch from Google to remove an optimization that didn't quite work.
348        The report of the bug said:
350          pcrecpp::RE("a*").FullMatch("aaa") matches, while
351          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
352          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
354    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
355        it matched the wrong number of bytes.
358  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
359  ---------------------  ---------------------

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