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

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