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revision 93 by nigel, Sat Feb 24 21:41:42 2007 UTC revision 215 by ph10, Wed Aug 15 14:20:05 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 09-Aug-07
5    ---------------------
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
13          #include "pcre.h"
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
35     6. ESC_K was left out of the EBCDIC table.
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
94    14. Optimized (?!) to (*FAIL).
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
113    Version 7.2 19-Jun-07
114    ---------------------
116     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
117        which is apparently normally available under Windows.
119     2. Re-jig the pcregrep tests with different newline settings in an attempt
120        to make them independent of the local environment's newline setting.
122     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
124     4. Some of the "internals" tests were previously cut out when the link size
125        was not 2, because the output contained actual offsets. The recent new
126        "Z" feature of pcretest means that these can be cut out, making the tests
127        usable with all link sizes.
129     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
130        stack recursion. This gives a massive performance boost under BSD, but just
131        a small improvement under Linux. However, it saves one field in the frame
132        in all cases.
134     6. Added more features from the forthcoming Perl 5.10:
136        (a) (?-n) (where n is a string of digits) is a relative subroutine or
137            recursion call. It refers to the nth most recently opened parentheses.
139        (b) (?+n) is also a relative subroutine call; it refers to the nth next
140            to be opened parentheses.
142        (c) Conditions that refer to capturing parentheses can be specified
143            relatively, for example, (?(-2)... or (?(+3)...
145        (d) \K resets the start of the current match so that everything before
146            is not part of it.
148        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
150        (f) \g{name} is another synonym - part of Perl 5.10's unification of
151            reference syntax.
153        (g) (?| introduces a group in which the numbering of parentheses in each
154            alternative starts with the same number.
156        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
158     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
161     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
162        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
163        for detecting groups that can match an empty string.
165     9. A pattern with a very large number of alternatives (more than several
166        hundred) was running out of internal workspace during the pre-compile
167        phase, where pcre_compile() figures out how much memory will be needed. A
168        bit of new cunning has reduced the workspace needed for groups with
169        alternatives. The 1000-alternative test pattern now uses 12 bytes of
170        workspace instead of running out of the 4096 that are available.
172    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
174    11. Applied patch from Google to remove an optimization that didn't quite work.
175        The report of the bug said:
177          pcrecpp::RE("a*").FullMatch("aaa") matches, while
178          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
179          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
181    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
182        it matched the wrong number of bytes.
185    Version 7.1 24-Apr-07
186    ---------------------
188     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
189        that is more "standard", making use of automake and other Autotools. There
190        is some re-arrangement of the files and adjustment of comments consequent
191        on this.
193     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
194        for recursive directory scanning broke on some systems because the files
195        are not scanned in any specific order and on different systems the order
196        was different. A call to "sort" has been inserted into RunGrepTest for the
197        approprate test as a short-term fix. In the longer term there may be an
198        alternative.
200     3. I had an email from Eric Raymond about problems translating some of PCRE's
201        man pages to HTML (despite the fact that I distribute HTML pages, some
202        people do their own conversions for various reasons). The problems
203        concerned the use of low-level troff macros .br and .in. I have therefore
204        removed all such uses from the man pages (some were redundant, some could
205        be replaced by .nf/.fi pairs). The 132html script that I use to generate
206        HTML has been updated to handle .nf/.fi and to complain if it encounters
207        .br or .in.
209     4. Updated comments in configure.ac that get placed in config.h.in and also
210        arranged for config.h to be included in the distribution, with the name
211        config.h.generic, for the benefit of those who have to compile without
212        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
214     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
215        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
216        makevp.bat for the current PCRE, using the additional files
217        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
219     6. A Windows user reported a minor discrepancy with test 2, which turned out
220        to be caused by a trailing space on an input line that had got lost in his
221        copy. The trailing space was an accident, so I've just removed it.
223     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
224        that is needed.
226     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
227        as "const" (a) because they are and (b) because it helps the PHP
228        maintainers who have recently made a script to detect big data structures
229        in the php code that should be moved to the .rodata section. I remembered
230        to update Builducptable as well, so it won't revert if ucptable.h is ever
231        re-created.
233     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
234        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
235        order to be able to cut out the UTF-8 tables in the latter when UTF-8
236        support is not required. This saves 1.5-2K of code, which is important in
237        some applications.
239        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
240        so as not to refer to the tables, even though these functions will never be
241        called when UTF-8 support is disabled. Otherwise there are problems with a
242        shared library.
244    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
246        (a) It was defining its arguments as char * instead of void *.
248        (b) It was assuming that all moves were upwards in memory; this was true
249            a long time ago when I wrote it, but is no longer the case.
251        The emulated memove() is provided for those environments that have neither
252        memmove() nor bcopy(). I didn't think anyone used it these days, but that
253        is clearly not the case, as these two bugs were recently reported.
255    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
256        and Detrail to create the HTML documentation, the .txt form of the man
257        pages, and it removes trailing spaces from listed files. It also creates
258        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
259        case, it wraps all the #defines with #ifndefs. This script should be run
260        before "make dist".
262    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
263        with Unicode property support.
265        (a) For a maximizing quantifier, if the two different cases of the
266            character were of different lengths in their UTF-8 codings (there are
267            some cases like this - I found 11), and the matching function had to
268            back up over a mixture of the two cases, it incorrectly assumed they
269            were both the same length.
271        (b) When PCRE was configured to use the heap rather than the stack for
272            recursion during matching, it was not correctly preserving the data for
273            the other case of a UTF-8 character when checking ahead for a match
274            while processing a minimizing repeat. If the check also involved
275            matching a wide character, but failed, corruption could cause an
276            erroneous result when trying to check for a repeat of the original
277            character.
279    13. Some tidying changes to the testing mechanism:
281        (a) The RunTest script now detects the internal link size and whether there
282            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
283            values substituted by "configure". (The RunGrepTest script already did
284            this for UTF-8.) The configure.ac script no longer substitutes the
285            relevant variables.
287        (b) The debugging options /B and /D in pcretest show the compiled bytecode
288            with length and offset values. This means that the output is different
289            for different internal link sizes. Test 2 is skipped for link sizes
290            other than 2 because of this, bypassing the problem. Unfortunately,
291            there was also a test in test 3 (the locale tests) that used /B and
292            failed for link sizes other than 2. Rather than cut the whole test out,
293            I have added a new /Z option to pcretest that replaces the length and
294            offset values with spaces. This is now used to make test 3 independent
295            of link size. (Test 2 will be tidied up later.)
297    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
298        segmentation fault instead of returning the appropriate error message.
300    15. In multiline mode when the newline sequence was set to "any", the pattern
301        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
302        This doesn't seem right; it now treats the CRLF combination as the line
303        ending, and so does not match in that case. It's only a pattern such as ^$
304        that would hit this one: something like ^ABC$ would have failed after \r
305        and then tried again after \r\n.
307    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
308        in an attempt to make files that differ only in their line terminators
309        compare equal. This works on Linux.
311    17. Under certain error circumstances pcregrep might try to free random memory
312        as it exited. This is now fixed, thanks to valgrind.
314    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
315        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
316        was because its rules for how to advance for /g after matching an empty
317        string at the end of a line did not allow for this case. They now check for
318        it specially.
320    20. pcretest is supposed to handle patterns and data of any length, by
321        extending its buffers when necessary. It was getting this wrong when the
322        buffer for a data line had to be extended.
324    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
325        CRLF as a newline sequence.
327    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
328        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
329        I have nevertheless tidied it up.
331    23. Added some casts to kill warnings from HP-UX ia64 compiler.
333    24. Added a man page for pcre-config.
336  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
337  ---------------------  ---------------------

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