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revision 164 by ph10, Fri May 4 15:11:14 2007 UTC revision 272 by ph10, Sat Nov 17 16:53:53 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.2 01-May-07  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.
40    Version 7.4 21-Sep-07
41    ---------------------
43    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
44        means that a class such as [\s] counted as "explicit reference to CR or
45        LF". That isn't really right - the whole point of the change was to try to
46        help when there was an actual mention of one of the two characters. So now
47        the change happens only if \r or \n (or a literal CR or LF) character is
48        encountered.
50    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
51        of both had grown to the point where there were only 3 bits left.
52        Fortunately, there was spare space in the data structure, and so I have
53        moved the internal flags into a new 16-bit field to free up more option
54        bits.
56    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
57        but did not set the internal JCHANGED flag - either of these is enough to
58        control the way the "get" function works - but the PCRE_INFO_JCHANGED
59        facility is supposed to tell if (?J) was ever used, so now (?J) at the
60        start sets both bits.
62    4.  Added options (at build time, compile time, exec time) to change \R from
63        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
65    5.  doc/pcresyntax.html was missing from the distribution.
67    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
68        compatibility, even though it is no longer used.
70    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
71        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
72        windows.h file is present (where different names are used). [This was
73        reversed later after testing - see 16 below.]
75    8.  Changed all #include <config.h> to #include "config.h". There were also
76        some further <pcre.h> cases that I changed to "pcre.h".
78    9.  When pcregrep was used with the --colour option, it missed the line ending
79        sequence off the lines that it output.
81    10. It was pointed out to me that arrays of string pointers cause lots of
82        relocations when a shared library is dynamically loaded. A technique of
83        using a single long string with a table of offsets can drastically reduce
84        these. I have refactored PCRE in four places to do this. The result is
85        dramatic:
87          Originally:                          290
88          After changing UCP table:            187
89          After changing error message table:   43
90          After changing table of "verbs"       36
91          After changing table of Posix names   22
93        Thanks to the folks working on Gregex for glib for this insight.
95    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
96        unicode-properties was also set.
98    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
100    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
101        checked only for CRLF.
103    14. Added casts to pcretest.c to avoid compiler warnings.
105    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
107    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
108        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
109        entirely. This removes changes made in 7 above.
111    17. The CMake files have been updated, and there is now more information about
112        building with CMake in the NON-UNIX-USE document.
115    Version 7.3 28-Aug-07
116    ---------------------
118     1. In the rejigging of the build system that eventually resulted in 7.1, the
119        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
120        brackets there is not right, since it causes compilers to look for an
121        installed pcre.h, not the version that is in the source that is being
122        compiled (which of course may be different). I have changed it back to:
124          #include "pcre.h"
126        I have a vague recollection that the change was concerned with compiling in
127        different directories, but in the new build system, that is taken care of
128        by the VPATH setting the Makefile.
130     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
131        when the subject happened to end in the byte 0x85 (e.g. if the last
132        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
133        characters but of course it shouldn't be taken as a newline when it is part
134        of another character. The bug was that, for an unlimited repeat of . in
135        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
136        characters when looking for a newline.
138     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
140     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
141        in debug output.
143     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
144        long printing in the pcrecpp unittest when running under MinGW.
146     6. ESC_K was left out of the EBCDIC table.
148     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
149        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
150        limit also applies to "virtual nesting" when a pattern is recursive, and in
151        this case 1000 isn't so big. I have been able to remove this limit at the
152        expense of backing off one optimization in certain circumstances. Normally,
153        when pcre_exec() would call its internal match() function recursively and
154        immediately return the result unconditionally, it uses a "tail recursion"
155        feature to save stack. However, when a subpattern that can match an empty
156        string has an unlimited repetition quantifier, it no longer makes this
157        optimization. That gives it a stack frame in which to save the data for
158        checking that an empty string has been matched. Previously this was taken
159        from the 1000-entry workspace that had been reserved. So now there is no
160        explicit limit, but more stack is used.
162     8. Applied Daniel's patches to solve problems with the import/export magic
163        syntax that is required for Windows, and which was going wrong for the
164        pcreposix and pcrecpp parts of the library. These were overlooked when this
165        problem was solved for the main library.
167     9. There were some crude static tests to avoid integer overflow when computing
168        the size of patterns that contain repeated groups with explicit upper
169        limits. As the maximum quantifier is 65535, the maximum group length was
170        set at 30,000 so that the product of these two numbers did not overflow a
171        32-bit integer. However, it turns out that people want to use groups that
172        are longer than 30,000 bytes (though not repeat them that many times).
173        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
174        made it possible to implement the integer overflow checks in a much more
175        dynamic way, which I have now done. The artificial limitation on group
176        length has been removed - we now have only the limit on the total length of
177        the compiled pattern, which depends on the LINK_SIZE setting.
179    10. Fixed a bug in the documentation for get/copy named substring when
180        duplicate names are permitted. If none of the named substrings are set, the
181        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
182        empty string.
184    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
185        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
186        because the ] is interpreted as the first data character and the
187        terminating ] is not found. PCRE has been made compatible with Perl in this
188        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
189        cause memory overwriting.
191    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
192        string has been matched (to stop an infinite loop). It was not recognizing
193        a conditional subpattern that could match an empty string if that
194        subpattern was within another subpattern. For example, it looped when
195        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
196        condition was not nested. This bug has been fixed.
198    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
199        past the start of the subject in the presence of bytes with the top bit
200        set, for example "\x8aBCD".
202    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
203        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
205    14. Optimized (?!) to (*FAIL).
207    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
208        This restricts code points to be within the range 0 to 0x10FFFF, excluding
209        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
210        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
211        does: it's just the validity check that is more restrictive.
213    16. Inserted checks for integer overflows during escape sequence (backslash)
214        processing, and also fixed erroneous offset values for syntax errors during
215        backslash processing.
217    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
218        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
220    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
221        caused an overrun.
223    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
224        something other than just ASCII characters) inside a group that had an
225        unlimited repeat caused a loop at compile time (while checking to see
226        whether the group could match an empty string).
228    20. Debugging a pattern containing \p or \P could cause a crash. For example,
229        [\P{Any}] did so. (Error in the code for printing property names.)
231    21. An orphan \E inside a character class could cause a crash.
233    22. A repeated capturing bracket such as (A)? could cause a wild memory
234        reference during compilation.
236    23. There are several functions in pcre_compile() that scan along a compiled
237        expression for various reasons (e.g. to see if it's fixed length for look
238        behind). There were bugs in these functions when a repeated \p or \P was
239        present in the pattern. These operators have additional parameters compared
240        with \d, etc, and these were not being taken into account when moving along
241        the compiled data. Specifically:
243        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
244            length.
246        (b) An item such as \pL+ within a repeated group could cause crashes or
247            loops.
249        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
250            "reference to non-existent subpattern" error.
252        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
254    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
255        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
257    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
259    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
260        character were causing crashes (broken optimization).
262    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
263        \p or \P) caused a compile-time loop.
265    28. More problems have arisen in unanchored patterns when CRLF is a valid line
266        break. For example, the unstudied pattern [\r\n]A does not match the string
267        "\r\nA" because change 7.0/46 below moves the current point on by two
268        characters after failing to match at the start. However, the pattern \nA
269        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
270        the same is true. There doesn't seem any very clean way out of this, but
271        what I have chosen to do makes the common cases work: PCRE now takes note
272        of whether there can be an explicit match for \r or \n anywhere in the
273        pattern, and if so, 7.0/46 no longer applies. As part of this change,
274        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
275        pattern has explicit CR or LF references.
277    29. Added (*CR) etc for changing newline setting at start of pattern.
280    Version 7.2 19-Jun-07
281  ---------------------  ---------------------
283   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
# Line 11  Version 7.2 01-May-07 Line 287  Version 7.2 01-May-07
287      to make them independent of the local environment's newline setting.      to make them independent of the local environment's newline setting.
289   3. Add code to configure.ac to remove -g from the CFLAGS default settings.   3. Add code to configure.ac to remove -g from the CFLAGS default settings.
291   4. Some of the "internals" tests were previously cut out when the link size   4. Some of the "internals" tests were previously cut out when the link size
292      was not 2, because the output contained actual offsets. The recent new      was not 2, because the output contained actual offsets. The recent new
293      "Z" feature of pcretest means that these can be cut out, making the tests      "Z" feature of pcretest means that these can be cut out, making the tests
294      usable with all link sizes.      usable with all link sizes.
296   5. Implemented Stan Switzer's goto replacement for longjmp() when not using   5. Implemented Stan Switzer's goto replacement for longjmp() when not using
297      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
298      a small improvement under Linux. However, it saves one field in the frame      a small improvement under Linux. However, it saves one field in the frame
299      in all cases.      in all cases.
301     6. Added more features from the forthcoming Perl 5.10:
303        (a) (?-n) (where n is a string of digits) is a relative subroutine or
304            recursion call. It refers to the nth most recently opened parentheses.
306        (b) (?+n) is also a relative subroutine call; it refers to the nth next
307            to be opened parentheses.
309        (c) Conditions that refer to capturing parentheses can be specified
310            relatively, for example, (?(-2)... or (?(+3)...
312        (d) \K resets the start of the current match so that everything before
313            is not part of it.
315        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
317        (f) \g{name} is another synonym - part of Perl 5.10's unification of
318            reference syntax.
320        (g) (?| introduces a group in which the numbering of parentheses in each
321            alternative starts with the same number.
323        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
325     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
328     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
329        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
330        for detecting groups that can match an empty string.
332     9. A pattern with a very large number of alternatives (more than several
333        hundred) was running out of internal workspace during the pre-compile
334        phase, where pcre_compile() figures out how much memory will be needed. A
335        bit of new cunning has reduced the workspace needed for groups with
336        alternatives. The 1000-alternative test pattern now uses 12 bytes of
337        workspace instead of running out of the 4096 that are available.
339    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
341    11. Applied patch from Google to remove an optimization that didn't quite work.
342        The report of the bug said:
344          pcrecpp::RE("a*").FullMatch("aaa") matches, while
345          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
346          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
348    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
349        it matched the wrong number of bytes.
352  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
353  ---------------------  ---------------------

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