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revision 96 by nigel, Fri Mar 2 13:10:43 2007 UTC revision 217 by ph10, Wed Aug 15 15:21:04 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 09-Aug-07
5    ---------------------
6    
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:
12    
13          #include "pcre.h"
14    
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.
18    
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.
26    
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
28    
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
31    
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.
34    
35     6. ESC_K was left out of the EBCDIC table.
36    
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.
50    
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.
55    
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.
67    
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.
72    
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.
79    
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.
86    
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".
90    
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
93    
94    14. Optimized (?!) to (*FAIL).
95    
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.
101    
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.
105    
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".
108    
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
111    
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
116    
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
119    
120    
121    Version 7.2 19-Jun-07
122    ---------------------
123    
124     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
125        which is apparently normally available under Windows.
126    
127     2. Re-jig the pcregrep tests with different newline settings in an attempt
128        to make them independent of the local environment's newline setting.
129    
130     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
131    
132     4. Some of the "internals" tests were previously cut out when the link size
133        was not 2, because the output contained actual offsets. The recent new
134        "Z" feature of pcretest means that these can be cut out, making the tests
135        usable with all link sizes.
136    
137     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
138        stack recursion. This gives a massive performance boost under BSD, but just
139        a small improvement under Linux. However, it saves one field in the frame
140        in all cases.
141    
142     6. Added more features from the forthcoming Perl 5.10:
143    
144        (a) (?-n) (where n is a string of digits) is a relative subroutine or
145            recursion call. It refers to the nth most recently opened parentheses.
146    
147        (b) (?+n) is also a relative subroutine call; it refers to the nth next
148            to be opened parentheses.
149    
150        (c) Conditions that refer to capturing parentheses can be specified
151            relatively, for example, (?(-2)... or (?(+3)...
152    
153        (d) \K resets the start of the current match so that everything before
154            is not part of it.
155    
156        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
157    
158        (f) \g{name} is another synonym - part of Perl 5.10's unification of
159            reference syntax.
160    
161        (g) (?| introduces a group in which the numbering of parentheses in each
162            alternative starts with the same number.
163    
164        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
165    
166     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
167        PCRE_INFO_JCHANGED.
168    
169     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
170        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
171        for detecting groups that can match an empty string.
172    
173     9. A pattern with a very large number of alternatives (more than several
174        hundred) was running out of internal workspace during the pre-compile
175        phase, where pcre_compile() figures out how much memory will be needed. A
176        bit of new cunning has reduced the workspace needed for groups with
177        alternatives. The 1000-alternative test pattern now uses 12 bytes of
178        workspace instead of running out of the 4096 that are available.
179    
180    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
181    
182    11. Applied patch from Google to remove an optimization that didn't quite work.
183        The report of the bug said:
184    
185          pcrecpp::RE("a*").FullMatch("aaa") matches, while
186          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
187          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
188    
189    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
190        it matched the wrong number of bytes.
191    
192    
193    Version 7.1 24-Apr-07
194    ---------------------
195    
196     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
197        that is more "standard", making use of automake and other Autotools. There
198        is some re-arrangement of the files and adjustment of comments consequent
199        on this.
200    
201     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
202        for recursive directory scanning broke on some systems because the files
203        are not scanned in any specific order and on different systems the order
204        was different. A call to "sort" has been inserted into RunGrepTest for the
205        approprate test as a short-term fix. In the longer term there may be an
206        alternative.
207    
208     3. I had an email from Eric Raymond about problems translating some of PCRE's
209        man pages to HTML (despite the fact that I distribute HTML pages, some
210        people do their own conversions for various reasons). The problems
211        concerned the use of low-level troff macros .br and .in. I have therefore
212        removed all such uses from the man pages (some were redundant, some could
213        be replaced by .nf/.fi pairs). The 132html script that I use to generate
214        HTML has been updated to handle .nf/.fi and to complain if it encounters
215        .br or .in.
216    
217     4. Updated comments in configure.ac that get placed in config.h.in and also
218        arranged for config.h to be included in the distribution, with the name
219        config.h.generic, for the benefit of those who have to compile without
220        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
221    
222     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
223        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
224        makevp.bat for the current PCRE, using the additional files
225        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
226    
227     6. A Windows user reported a minor discrepancy with test 2, which turned out
228        to be caused by a trailing space on an input line that had got lost in his
229        copy. The trailing space was an accident, so I've just removed it.
230    
231     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
232        that is needed.
233    
234     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
235        as "const" (a) because they are and (b) because it helps the PHP
236        maintainers who have recently made a script to detect big data structures
237        in the php code that should be moved to the .rodata section. I remembered
238        to update Builducptable as well, so it won't revert if ucptable.h is ever
239        re-created.
240    
241     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
242        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
243        order to be able to cut out the UTF-8 tables in the latter when UTF-8
244        support is not required. This saves 1.5-2K of code, which is important in
245        some applications.
246    
247        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
248        so as not to refer to the tables, even though these functions will never be
249        called when UTF-8 support is disabled. Otherwise there are problems with a
250        shared library.
251    
252    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
253    
254        (a) It was defining its arguments as char * instead of void *.
255    
256        (b) It was assuming that all moves were upwards in memory; this was true
257            a long time ago when I wrote it, but is no longer the case.
258    
259        The emulated memove() is provided for those environments that have neither
260        memmove() nor bcopy(). I didn't think anyone used it these days, but that
261        is clearly not the case, as these two bugs were recently reported.
262    
263    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
264        and Detrail to create the HTML documentation, the .txt form of the man
265        pages, and it removes trailing spaces from listed files. It also creates
266        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
267        case, it wraps all the #defines with #ifndefs. This script should be run
268        before "make dist".
269    
270    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
271        with Unicode property support.
272    
273        (a) For a maximizing quantifier, if the two different cases of the
274            character were of different lengths in their UTF-8 codings (there are
275            some cases like this - I found 11), and the matching function had to
276            back up over a mixture of the two cases, it incorrectly assumed they
277            were both the same length.
278    
279        (b) When PCRE was configured to use the heap rather than the stack for
280            recursion during matching, it was not correctly preserving the data for
281            the other case of a UTF-8 character when checking ahead for a match
282            while processing a minimizing repeat. If the check also involved
283            matching a wide character, but failed, corruption could cause an
284            erroneous result when trying to check for a repeat of the original
285            character.
286    
287    13. Some tidying changes to the testing mechanism:
288    
289        (a) The RunTest script now detects the internal link size and whether there
290            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
291            values substituted by "configure". (The RunGrepTest script already did
292            this for UTF-8.) The configure.ac script no longer substitutes the
293            relevant variables.
294    
295        (b) The debugging options /B and /D in pcretest show the compiled bytecode
296            with length and offset values. This means that the output is different
297            for different internal link sizes. Test 2 is skipped for link sizes
298            other than 2 because of this, bypassing the problem. Unfortunately,
299            there was also a test in test 3 (the locale tests) that used /B and
300            failed for link sizes other than 2. Rather than cut the whole test out,
301            I have added a new /Z option to pcretest that replaces the length and
302            offset values with spaces. This is now used to make test 3 independent
303            of link size. (Test 2 will be tidied up later.)
304    
305    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
306        segmentation fault instead of returning the appropriate error message.
307    
308    15. In multiline mode when the newline sequence was set to "any", the pattern
309        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
310        This doesn't seem right; it now treats the CRLF combination as the line
311        ending, and so does not match in that case. It's only a pattern such as ^$
312        that would hit this one: something like ^ABC$ would have failed after \r
313        and then tried again after \r\n.
314    
315    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
316        in an attempt to make files that differ only in their line terminators
317        compare equal. This works on Linux.
318    
319    17. Under certain error circumstances pcregrep might try to free random memory
320        as it exited. This is now fixed, thanks to valgrind.
321    
322    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
323        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
324        was because its rules for how to advance for /g after matching an empty
325        string at the end of a line did not allow for this case. They now check for
326        it specially.
327    
328    20. pcretest is supposed to handle patterns and data of any length, by
329        extending its buffers when necessary. It was getting this wrong when the
330        buffer for a data line had to be extended.
331    
332    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
333        CRLF as a newline sequence.
334    
335    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
336        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
337        I have nevertheless tidied it up.
338    
339    23. Added some casts to kill warnings from HP-UX ia64 compiler.
340    
341    24. Added a man page for pcre-config.
342    
343    
344  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
345  ---------------------  ---------------------
346    

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