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revision 165 by ph10, Wed May 9 10:50:57 2007 UTC revision 265 by ph10, Wed Nov 14 11:35:48 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:].
18    Version 7.4 21-Sep-07
19    ---------------------
21    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
22        means that a class such as [\s] counted as "explicit reference to CR or
23        LF". That isn't really right - the whole point of the change was to try to
24        help when there was an actual mention of one of the two characters. So now
25        the change happens only if \r or \n (or a literal CR or LF) character is
26        encountered.
28    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
29        of both had grown to the point where there were only 3 bits left.
30        Fortunately, there was spare space in the data structure, and so I have
31        moved the internal flags into a new 16-bit field to free up more option
32        bits.
34    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
35        but did not set the internal JCHANGED flag - either of these is enough to
36        control the way the "get" function works - but the PCRE_INFO_JCHANGED
37        facility is supposed to tell if (?J) was ever used, so now (?J) at the
38        start sets both bits.
40    4.  Added options (at build time, compile time, exec time) to change \R from
41        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
43    5.  doc/pcresyntax.html was missing from the distribution.
45    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
46        compatibility, even though it is no longer used.
48    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
49        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
50        windows.h file is present (where different names are used). [This was
51        reversed later after testing - see 16 below.]
53    8.  Changed all #include <config.h> to #include "config.h". There were also
54        some further <pcre.h> cases that I changed to "pcre.h".
56    9.  When pcregrep was used with the --colour option, it missed the line ending
57        sequence off the lines that it output.
59    10. It was pointed out to me that arrays of string pointers cause lots of
60        relocations when a shared library is dynamically loaded. A technique of
61        using a single long string with a table of offsets can drastically reduce
62        these. I have refactored PCRE in four places to do this. The result is
63        dramatic:
65          Originally:                          290
66          After changing UCP table:            187
67          After changing error message table:   43
68          After changing table of "verbs"       36
69          After changing table of Posix names   22
71        Thanks to the folks working on Gregex for glib for this insight.
73    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
74        unicode-properties was also set.
76    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
78    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
79        checked only for CRLF.
81    14. Added casts to pcretest.c to avoid compiler warnings.
83    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
85    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
86        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
87        entirely. This removes changes made in 7 above.
89    17. The CMake files have been updated, and there is now more information about
90        building with CMake in the NON-UNIX-USE document.
93    Version 7.3 28-Aug-07
94    ---------------------
96     1. In the rejigging of the build system that eventually resulted in 7.1, the
97        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
98        brackets there is not right, since it causes compilers to look for an
99        installed pcre.h, not the version that is in the source that is being
100        compiled (which of course may be different). I have changed it back to:
102          #include "pcre.h"
104        I have a vague recollection that the change was concerned with compiling in
105        different directories, but in the new build system, that is taken care of
106        by the VPATH setting the Makefile.
108     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
109        when the subject happened to end in the byte 0x85 (e.g. if the last
110        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
111        characters but of course it shouldn't be taken as a newline when it is part
112        of another character. The bug was that, for an unlimited repeat of . in
113        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
114        characters when looking for a newline.
116     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
118     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
119        in debug output.
121     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
122        long printing in the pcrecpp unittest when running under MinGW.
124     6. ESC_K was left out of the EBCDIC table.
126     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
127        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
128        limit also applies to "virtual nesting" when a pattern is recursive, and in
129        this case 1000 isn't so big. I have been able to remove this limit at the
130        expense of backing off one optimization in certain circumstances. Normally,
131        when pcre_exec() would call its internal match() function recursively and
132        immediately return the result unconditionally, it uses a "tail recursion"
133        feature to save stack. However, when a subpattern that can match an empty
134        string has an unlimited repetition quantifier, it no longer makes this
135        optimization. That gives it a stack frame in which to save the data for
136        checking that an empty string has been matched. Previously this was taken
137        from the 1000-entry workspace that had been reserved. So now there is no
138        explicit limit, but more stack is used.
140     8. Applied Daniel's patches to solve problems with the import/export magic
141        syntax that is required for Windows, and which was going wrong for the
142        pcreposix and pcrecpp parts of the library. These were overlooked when this
143        problem was solved for the main library.
145     9. There were some crude static tests to avoid integer overflow when computing
146        the size of patterns that contain repeated groups with explicit upper
147        limits. As the maximum quantifier is 65535, the maximum group length was
148        set at 30,000 so that the product of these two numbers did not overflow a
149        32-bit integer. However, it turns out that people want to use groups that
150        are longer than 30,000 bytes (though not repeat them that many times).
151        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
152        made it possible to implement the integer overflow checks in a much more
153        dynamic way, which I have now done. The artificial limitation on group
154        length has been removed - we now have only the limit on the total length of
155        the compiled pattern, which depends on the LINK_SIZE setting.
157    10. Fixed a bug in the documentation for get/copy named substring when
158        duplicate names are permitted. If none of the named substrings are set, the
159        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
160        empty string.
162    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
163        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
164        because the ] is interpreted as the first data character and the
165        terminating ] is not found. PCRE has been made compatible with Perl in this
166        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
167        cause memory overwriting.
169    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
170        string has been matched (to stop an infinite loop). It was not recognizing
171        a conditional subpattern that could match an empty string if that
172        subpattern was within another subpattern. For example, it looped when
173        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
174        condition was not nested. This bug has been fixed.
176    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
177        past the start of the subject in the presence of bytes with the top bit
178        set, for example "\x8aBCD".
180    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
181        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
183    14. Optimized (?!) to (*FAIL).
185    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
186        This restricts code points to be within the range 0 to 0x10FFFF, excluding
187        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
188        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
189        does: it's just the validity check that is more restrictive.
191    16. Inserted checks for integer overflows during escape sequence (backslash)
192        processing, and also fixed erroneous offset values for syntax errors during
193        backslash processing.
195    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
196        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
198    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
199        caused an overrun.
201    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
202        something other than just ASCII characters) inside a group that had an
203        unlimited repeat caused a loop at compile time (while checking to see
204        whether the group could match an empty string).
206    20. Debugging a pattern containing \p or \P could cause a crash. For example,
207        [\P{Any}] did so. (Error in the code for printing property names.)
209    21. An orphan \E inside a character class could cause a crash.
211    22. A repeated capturing bracket such as (A)? could cause a wild memory
212        reference during compilation.
214    23. There are several functions in pcre_compile() that scan along a compiled
215        expression for various reasons (e.g. to see if it's fixed length for look
216        behind). There were bugs in these functions when a repeated \p or \P was
217        present in the pattern. These operators have additional parameters compared
218        with \d, etc, and these were not being taken into account when moving along
219        the compiled data. Specifically:
221        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
222            length.
224        (b) An item such as \pL+ within a repeated group could cause crashes or
225            loops.
227        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
228            "reference to non-existent subpattern" error.
230        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
232    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
233        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
235    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
237    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
238        character were causing crashes (broken optimization).
240    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
241        \p or \P) caused a compile-time loop.
243    28. More problems have arisen in unanchored patterns when CRLF is a valid line
244        break. For example, the unstudied pattern [\r\n]A does not match the string
245        "\r\nA" because change 7.0/46 below moves the current point on by two
246        characters after failing to match at the start. However, the pattern \nA
247        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
248        the same is true. There doesn't seem any very clean way out of this, but
249        what I have chosen to do makes the common cases work: PCRE now takes note
250        of whether there can be an explicit match for \r or \n anywhere in the
251        pattern, and if so, 7.0/46 no longer applies. As part of this change,
252        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
253        pattern has explicit CR or LF references.
255    29. Added (*CR) etc for changing newline setting at start of pattern.
258    Version 7.2 19-Jun-07
259  ---------------------  ---------------------
261   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 22  Version 7.2 01-May-07 Line 276  Version 7.2 01-May-07
276      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
277      in all cases.      in all cases.
279     6. Added more features from the forthcoming Perl 5.10:
281        (a) (?-n) (where n is a string of digits) is a relative subroutine or
282            recursion call. It refers to the nth most recently opened parentheses.
284        (b) (?+n) is also a relative subroutine call; it refers to the nth next
285            to be opened parentheses.
287        (c) Conditions that refer to capturing parentheses can be specified
288            relatively, for example, (?(-2)... or (?(+3)...
290        (d) \K resets the start of the current match so that everything before
291            is not part of it.
293        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
295        (f) \g{name} is another synonym - part of Perl 5.10's unification of
296            reference syntax.
298        (g) (?| introduces a group in which the numbering of parentheses in each
299            alternative starts with the same number.
301        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
303     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
306     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
307        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
308        for detecting groups that can match an empty string.
310     9. A pattern with a very large number of alternatives (more than several
311        hundred) was running out of internal workspace during the pre-compile
312        phase, where pcre_compile() figures out how much memory will be needed. A
313        bit of new cunning has reduced the workspace needed for groups with
314        alternatives. The 1000-alternative test pattern now uses 12 bytes of
315        workspace instead of running out of the 4096 that are available.
317    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
319    11. Applied patch from Google to remove an optimization that didn't quite work.
320        The report of the bug said:
322          pcrecpp::RE("a*").FullMatch("aaa") matches, while
323          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
324          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
326    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
327        it matched the wrong number of bytes.
330  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
331  ---------------------  ---------------------

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