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

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