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revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC revision 161 by ph10, Thu May 3 10:28:07 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.2 01-May-07
5    ---------------------
6    
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8        which is apparently normally available under Windows.
9    
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11        to make them independent of the local environment's newline setting.
12    
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
14    
15     4. Some of the "internals" tests were previously cut out when the link size
16        was not 2, because the output contained actual offsets. The recent new
17        "Z" feature of pcretest means that these can be cut out, making the tests
18        usable with all link sizes.
19    
20    
21    Version 7.1 24-Apr-07
22    ---------------------
23    
24     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
25        that is more "standard", making use of automake and other Autotools. There
26        is some re-arrangement of the files and adjustment of comments consequent
27        on this.
28    
29     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
30        for recursive directory scanning broke on some systems because the files
31        are not scanned in any specific order and on different systems the order
32        was different. A call to "sort" has been inserted into RunGrepTest for the
33        approprate test as a short-term fix. In the longer term there may be an
34        alternative.
35    
36     3. I had an email from Eric Raymond about problems translating some of PCRE's
37        man pages to HTML (despite the fact that I distribute HTML pages, some
38        people do their own conversions for various reasons). The problems
39        concerned the use of low-level troff macros .br and .in. I have therefore
40        removed all such uses from the man pages (some were redundant, some could
41        be replaced by .nf/.fi pairs). The 132html script that I use to generate
42        HTML has been updated to handle .nf/.fi and to complain if it encounters
43        .br or .in.
44    
45     4. Updated comments in configure.ac that get placed in config.h.in and also
46        arranged for config.h to be included in the distribution, with the name
47        config.h.generic, for the benefit of those who have to compile without
48        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
49    
50     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
51        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
52        makevp.bat for the current PCRE, using the additional files
53        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
54    
55     6. A Windows user reported a minor discrepancy with test 2, which turned out
56        to be caused by a trailing space on an input line that had got lost in his
57        copy. The trailing space was an accident, so I've just removed it.
58    
59     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
60        that is needed.
61    
62     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
63        as "const" (a) because they are and (b) because it helps the PHP
64        maintainers who have recently made a script to detect big data structures
65        in the php code that should be moved to the .rodata section. I remembered
66        to update Builducptable as well, so it won't revert if ucptable.h is ever
67        re-created.
68    
69     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
70        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
71        order to be able to cut out the UTF-8 tables in the latter when UTF-8
72        support is not required. This saves 1.5-2K of code, which is important in
73        some applications.
74    
75        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
76        so as not to refer to the tables, even though these functions will never be
77        called when UTF-8 support is disabled. Otherwise there are problems with a
78        shared library.
79    
80    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
81    
82        (a) It was defining its arguments as char * instead of void *.
83    
84        (b) It was assuming that all moves were upwards in memory; this was true
85            a long time ago when I wrote it, but is no longer the case.
86    
87        The emulated memove() is provided for those environments that have neither
88        memmove() nor bcopy(). I didn't think anyone used it these days, but that
89        is clearly not the case, as these two bugs were recently reported.
90    
91    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
92        and Detrail to create the HTML documentation, the .txt form of the man
93        pages, and it removes trailing spaces from listed files. It also creates
94        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
95        case, it wraps all the #defines with #ifndefs. This script should be run
96        before "make dist".
97    
98    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
99        with Unicode property support.
100    
101        (a) For a maximizing quantifier, if the two different cases of the
102            character were of different lengths in their UTF-8 codings (there are
103            some cases like this - I found 11), and the matching function had to
104            back up over a mixture of the two cases, it incorrectly assumed they
105            were both the same length.
106    
107        (b) When PCRE was configured to use the heap rather than the stack for
108            recursion during matching, it was not correctly preserving the data for
109            the other case of a UTF-8 character when checking ahead for a match
110            while processing a minimizing repeat. If the check also involved
111            matching a wide character, but failed, corruption could cause an
112            erroneous result when trying to check for a repeat of the original
113            character.
114    
115    13. Some tidying changes to the testing mechanism:
116    
117        (a) The RunTest script now detects the internal link size and whether there
118            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
119            values substituted by "configure". (The RunGrepTest script already did
120            this for UTF-8.) The configure.ac script no longer substitutes the
121            relevant variables.
122    
123        (b) The debugging options /B and /D in pcretest show the compiled bytecode
124            with length and offset values. This means that the output is different
125            for different internal link sizes. Test 2 is skipped for link sizes
126            other than 2 because of this, bypassing the problem. Unfortunately,
127            there was also a test in test 3 (the locale tests) that used /B and
128            failed for link sizes other than 2. Rather than cut the whole test out,
129            I have added a new /Z option to pcretest that replaces the length and
130            offset values with spaces. This is now used to make test 3 independent
131            of link size. (Test 2 will be tidied up later.)
132    
133    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
134        segmentation fault instead of returning the appropriate error message.
135    
136    15. In multiline mode when the newline sequence was set to "any", the pattern
137        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
138        This doesn't seem right; it now treats the CRLF combination as the line
139        ending, and so does not match in that case. It's only a pattern such as ^$
140        that would hit this one: something like ^ABC$ would have failed after \r
141        and then tried again after \r\n.
142    
143    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
144        in an attempt to make files that differ only in their line terminators
145        compare equal. This works on Linux.
146    
147    17. Under certain error circumstances pcregrep might try to free random memory
148        as it exited. This is now fixed, thanks to valgrind.
149    
150    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
151        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
152        was because its rules for how to advance for /g after matching an empty
153        string at the end of a line did not allow for this case. They now check for
154        it specially.
155    
156    20. pcretest is supposed to handle patterns and data of any length, by
157        extending its buffers when necessary. It was getting this wrong when the
158        buffer for a data line had to be extended.
159    
160    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
161        CRLF as a newline sequence.
162    
163    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
164        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
165        I have nevertheless tidied it up.
166    
167    23. Added some casts to kill warnings from HP-UX ia64 compiler.
168    
169    24. Added a man page for pcre-config.
170    
171    
172    Version 7.0 19-Dec-06
173    ---------------------
174    
175     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
176        moving to gcc 4.1.1.
177    
178     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
179        sys/time.h, which is documented as needed for this function. It doesn't
180        seem to matter on Linux, but it showed up on some releases of OS X.
181    
182     3. It seems that there are systems where bytes whose values are greater than
183        127 match isprint() in the "C" locale. The "C" locale should be the
184        default when a C program starts up. In most systems, only ASCII printing
185        characters match isprint(). This difference caused the output from pcretest
186        to vary, making some of the tests fail. I have changed pcretest so that:
187    
188        (a) When it is outputting text in the compiled version of a pattern, bytes
189            other than 32-126 are always shown as hex escapes.
190    
191        (b) When it is outputting text that is a matched part of a subject string,
192            it does the same, unless a different locale has been set for the match
193            (using the /L modifier). In this case, it uses isprint() to decide.
194    
195     4. Fixed a major bug that caused incorrect computation of the amount of memory
196        required for a compiled pattern when options that changed within the
197        pattern affected the logic of the preliminary scan that determines the
198        length. The relevant options are -x, and -i in UTF-8 mode. The result was
199        that the computed length was too small. The symptoms of this bug were
200        either the PCRE error "internal error: code overflow" from pcre_compile(),
201        or a glibc crash with a message such as "pcretest: free(): invalid next
202        size (fast)". Examples of patterns that provoked this bug (shown in
203        pcretest format) are:
204    
205          /(?-x: )/x
206          /(?x)(?-x: \s*#\s*)/
207          /((?i)[\x{c0}])/8
208          /(?i:[\x{c0}])/8
209    
210        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
211        is now done differently.
212    
213     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
214        wrapper classes; (b) implement a new function in the C++ scanner that is
215        more efficient than the old way of doing things because it avoids levels of
216        recursion in the regex matching; (c) add a paragraph to the documentation
217        for the FullMatch() function.
218    
219     6. The escape sequence \n was being treated as whatever was defined as
220        "newline". Not only was this contrary to the documentation, which states
221        that \n is character 10 (hex 0A), but it also went horribly wrong when
222        "newline" was defined as CRLF. This has been fixed.
223    
224     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
225        was being set to -1 for the "end of line" case (supposedly a value that no
226        character can have). Though this value is never used (the check for end of
227        line is "zero bytes in current character"), it caused compiler complaints.
228        I've changed it to 0xffffffff.
229    
230     8. In pcre_version.c, the version string was being built by a sequence of
231        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
232        string (as it is for production releases) called a macro with an empty
233        argument. The C standard says the result of this is undefined. The gcc
234        compiler treats it as an empty string (which was what was wanted) but it is
235        reported that Visual C gives an error. The source has been hacked around to
236        avoid this problem.
237    
238     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
239        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
240        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
241        of them did).
242    
243    10. Originally, pcretest opened its input and output without "b"; then I was
244        told that "b" was needed in some environments, so it was added for release
245        5.0 to both the input and output. (It makes no difference on Unix-like
246        systems.) Later I was told that it is wrong for the input on Windows. I've
247        now abstracted the modes into two macros, to make it easier to fiddle with
248        them, and removed "b" from the input mode under Windows.
249    
250    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
251    
252    12. Added -help and --help to pcretest as an official way of being reminded
253        of the options.
254    
255    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
256        and pcrecpp.cc because they annoy compilers at high warning levels.
257    
258    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
259    
260    15. Fixed an occurrence of == in configure.ac that should have been = (shell
261        scripts are not C programs :-) and which was not noticed because it works
262        on Linux.
263    
264    16. pcretest is supposed to handle any length of pattern and data line (as one
265        line or as a continued sequence of lines) by extending its input buffer if
266        necessary. This feature was broken for very long pattern lines, leading to
267        a string of junk being passed to pcre_compile() if the pattern was longer
268        than about 50K.
269    
270    17. I have done a major re-factoring of the way pcre_compile() computes the
271        amount of memory needed for a compiled pattern. Previously, there was code
272        that made a preliminary scan of the pattern in order to do this. That was
273        OK when PCRE was new, but as the facilities have expanded, it has become
274        harder and harder to keep it in step with the real compile phase, and there
275        have been a number of bugs (see for example, 4 above). I have now found a
276        cunning way of running the real compile function in a "fake" mode that
277        enables it to compute how much memory it would need, while actually only
278        ever using a few hundred bytes of working memory and without too many
279        tests of the mode. This should make future maintenance and development
280        easier. A side effect of this work is that the limit of 200 on the nesting
281        depth of parentheses has been removed (though this was never a serious
282        limitation, I suspect). However, there is a downside: pcre_compile() now
283        runs more slowly than before (30% or more, depending on the pattern). I
284        hope this isn't a big issue. There is no effect on runtime performance.
285    
286    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
287        newline (only possible for the last line of a file) and it was a
288        pattern that set a locale (followed by /Lsomething), pcretest crashed.
289    
290    19. Added additional timing features to pcretest. (1) The -tm option now times
291        matching only, not compiling. (2) Both -t and -tm can be followed, as a
292        separate command line item, by a number that specifies the number of
293        repeats to use when timing. The default is 50000; this gives better
294        precision, but takes uncomfortably long for very large patterns.
295    
296    20. Extended pcre_study() to be more clever in cases where a branch of a
297        subpattern has no definite first character. For example, (a*|b*)[cd] would
298        previously give no result from pcre_study(). Now it recognizes that the
299        first character must be a, b, c, or d.
300    
301    21. There was an incorrect error "recursive call could loop indefinitely" if
302        a subpattern (or the entire pattern) that was being tested for matching an
303        empty string contained only one non-empty item after a nested subpattern.
304        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
305        incorrectly, because the \d was being skipped in the check.
306    
307    22. The pcretest program now has a new pattern option /B and a command line
308        option -b, which is equivalent to adding /B to every pattern. This causes
309        it to show the compiled bytecode, without the additional information that
310        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
311        is the same as /B/I).
312    
313    23. A new optimization is now able automatically to treat some sequences such
314        as a*b as a*+b. More specifically, if something simple (such as a character
315        or a simple class like \d) has an unlimited quantifier, and is followed by
316        something that cannot possibly match the quantified thing, the quantifier
317        is automatically "possessified".
318    
319    24. A recursive reference to a subpattern whose number was greater than 39
320        went wrong under certain circumstances in UTF-8 mode. This bug could also
321        have affected the operation of pcre_study().
322    
323    25. Realized that a little bit of performance could be had by replacing
324        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
325    
326    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
327    
328    27. Possessive quantifiers such as a++ were previously implemented by turning
329        them into atomic groups such as ($>a+). Now they have their own opcodes,
330        which improves performance. This includes the automatically created ones
331        from 23 above.
332    
333    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
334        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
335        the first matched character to be a colon. This applied both to named and
336        numbered groups.
337    
338    29. The ucpinternal.h header file was missing its idempotency #ifdef.
339    
340    30. I was sent a "project" file called libpcre.a.dev which I understand makes
341        building PCRE on Windows easier, so I have included it in the distribution.
342    
343    31. There is now a check in pcretest against a ridiculously large number being
344        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
345        loop, the loop is abandoned.
346    
347    32. Forward references to subpatterns in conditions such as (?(2)...) where
348        subpattern 2 is defined later cause pcre_compile() to search forwards in
349        the pattern for the relevant set of parentheses. This search went wrong
350        when there were unescaped parentheses in a character class, parentheses
351        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
352    
353    33. "Subroutine" calls and backreferences were previously restricted to
354        referencing subpatterns earlier in the regex. This restriction has now
355        been removed.
356    
357    34. Added a number of extra features that are going to be in Perl 5.10. On the
358        whole, these are just syntactic alternatives for features that PCRE had
359        previously implemented using the Python syntax or my own invention. The
360        other formats are all retained for compatibility.
361    
362        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
363            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
364            also .NET compatible.
365    
366        (b) A recursion or subroutine call to a named group can now be defined as
367            (?&name) as well as (?P>name).
368    
369        (c) A backreference to a named group can now be defined as \k<name> or
370            \k'name' as well as (?P=name). The new forms, as well as being in Perl
371            5.10, are also .NET compatible.
372    
373        (d) A conditional reference to a named group can now use the syntax
374            (?(<name>) or (?('name') as well as (?(name).
375    
376        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
377            groups (named and numbered) that are never evaluated inline, but can be
378            called as "subroutines" from elsewhere. In effect, the DEFINE condition
379            is always false. There may be only one alternative in such a group.
380    
381        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
382            as the simple (?(R). The condition is true only if the most recent
383            recursion is that of the given number or name. It does not search out
384            through the entire recursion stack.
385    
386        (g) The escape \gN or \g{N} has been added, where N is a positive or
387            negative number, specifying an absolute or relative reference.
388    
389    35. Tidied to get rid of some further signed/unsigned compiler warnings and
390        some "unreachable code" warnings.
391    
392    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
393        things, this adds five new scripts.
394    
395    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
396        There were also incompatibilities regarding the handling of \Q..\E inside
397        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
398        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
399    
400    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
401        matches an empty string, and forcibly breaks the loop. There were bugs in
402        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
403        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
404        separate and independent bugs (that affected different cases) have been
405        fixed.
406    
407    39. Refactored the code to abolish the use of different opcodes for small
408        capturing bracket numbers. This is a tidy that I avoided doing when I
409        removed the limit on the number of capturing brackets for 3.5 back in 2001.
410        The new approach is not only tidier, it makes it possible to reduce the
411        memory needed to fix the previous bug (38).
412    
413    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
414        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
415        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
416        mode.
417    
418    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
419        report.
420    
421    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
422        copy construction and assignment in the C++ wrapper.
423    
424    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
425        couple of bugs that could have given wrong results in the "--newline=crlf"
426        case.
427    
428    44. Added a number of casts and did some reorganization of signed/unsigned int
429        variables following suggestions from Dair Grant. Also renamed the variable
430        "this" as "item" because it is a C++ keyword.
431    
432    45. Arranged for dftables to add
433    
434          #include "pcre_internal.h"
435    
436        to pcre_chartables.c because without it, gcc 4.x may remove the array
437        definition from the final binary if PCRE is built into a static library and
438        dead code stripping is activated.
439    
440    46. For an unanchored pattern, if a match attempt fails at the start of a
441        newline sequence, and the newline setting is CRLF or ANY, and the next two
442        characters are CRLF, advance by two characters instead of one.
443    
444    
445  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
446  ---------------------  ---------------------
447    

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