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revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC revision 164 by ph10, Fri May 4 15:11:14 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     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21        stack recursion. This gives a massive performance boost under BSD, but just
22        a small improvement under Linux. However, it saves one field in the frame
23        in all cases.
24    
25    
26    Version 7.1 24-Apr-07
27    ---------------------
28    
29     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
30        that is more "standard", making use of automake and other Autotools. There
31        is some re-arrangement of the files and adjustment of comments consequent
32        on this.
33    
34     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
35        for recursive directory scanning broke on some systems because the files
36        are not scanned in any specific order and on different systems the order
37        was different. A call to "sort" has been inserted into RunGrepTest for the
38        approprate test as a short-term fix. In the longer term there may be an
39        alternative.
40    
41     3. I had an email from Eric Raymond about problems translating some of PCRE's
42        man pages to HTML (despite the fact that I distribute HTML pages, some
43        people do their own conversions for various reasons). The problems
44        concerned the use of low-level troff macros .br and .in. I have therefore
45        removed all such uses from the man pages (some were redundant, some could
46        be replaced by .nf/.fi pairs). The 132html script that I use to generate
47        HTML has been updated to handle .nf/.fi and to complain if it encounters
48        .br or .in.
49    
50     4. Updated comments in configure.ac that get placed in config.h.in and also
51        arranged for config.h to be included in the distribution, with the name
52        config.h.generic, for the benefit of those who have to compile without
53        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
54    
55     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
56        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
57        makevp.bat for the current PCRE, using the additional files
58        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
59    
60     6. A Windows user reported a minor discrepancy with test 2, which turned out
61        to be caused by a trailing space on an input line that had got lost in his
62        copy. The trailing space was an accident, so I've just removed it.
63    
64     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
65        that is needed.
66    
67     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
68        as "const" (a) because they are and (b) because it helps the PHP
69        maintainers who have recently made a script to detect big data structures
70        in the php code that should be moved to the .rodata section. I remembered
71        to update Builducptable as well, so it won't revert if ucptable.h is ever
72        re-created.
73    
74     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
75        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
76        order to be able to cut out the UTF-8 tables in the latter when UTF-8
77        support is not required. This saves 1.5-2K of code, which is important in
78        some applications.
79    
80        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
81        so as not to refer to the tables, even though these functions will never be
82        called when UTF-8 support is disabled. Otherwise there are problems with a
83        shared library.
84    
85    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
86    
87        (a) It was defining its arguments as char * instead of void *.
88    
89        (b) It was assuming that all moves were upwards in memory; this was true
90            a long time ago when I wrote it, but is no longer the case.
91    
92        The emulated memove() is provided for those environments that have neither
93        memmove() nor bcopy(). I didn't think anyone used it these days, but that
94        is clearly not the case, as these two bugs were recently reported.
95    
96    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
97        and Detrail to create the HTML documentation, the .txt form of the man
98        pages, and it removes trailing spaces from listed files. It also creates
99        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
100        case, it wraps all the #defines with #ifndefs. This script should be run
101        before "make dist".
102    
103    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
104        with Unicode property support.
105    
106        (a) For a maximizing quantifier, if the two different cases of the
107            character were of different lengths in their UTF-8 codings (there are
108            some cases like this - I found 11), and the matching function had to
109            back up over a mixture of the two cases, it incorrectly assumed they
110            were both the same length.
111    
112        (b) When PCRE was configured to use the heap rather than the stack for
113            recursion during matching, it was not correctly preserving the data for
114            the other case of a UTF-8 character when checking ahead for a match
115            while processing a minimizing repeat. If the check also involved
116            matching a wide character, but failed, corruption could cause an
117            erroneous result when trying to check for a repeat of the original
118            character.
119    
120    13. Some tidying changes to the testing mechanism:
121    
122        (a) The RunTest script now detects the internal link size and whether there
123            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
124            values substituted by "configure". (The RunGrepTest script already did
125            this for UTF-8.) The configure.ac script no longer substitutes the
126            relevant variables.
127    
128        (b) The debugging options /B and /D in pcretest show the compiled bytecode
129            with length and offset values. This means that the output is different
130            for different internal link sizes. Test 2 is skipped for link sizes
131            other than 2 because of this, bypassing the problem. Unfortunately,
132            there was also a test in test 3 (the locale tests) that used /B and
133            failed for link sizes other than 2. Rather than cut the whole test out,
134            I have added a new /Z option to pcretest that replaces the length and
135            offset values with spaces. This is now used to make test 3 independent
136            of link size. (Test 2 will be tidied up later.)
137    
138    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
139        segmentation fault instead of returning the appropriate error message.
140    
141    15. In multiline mode when the newline sequence was set to "any", the pattern
142        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
143        This doesn't seem right; it now treats the CRLF combination as the line
144        ending, and so does not match in that case. It's only a pattern such as ^$
145        that would hit this one: something like ^ABC$ would have failed after \r
146        and then tried again after \r\n.
147    
148    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
149        in an attempt to make files that differ only in their line terminators
150        compare equal. This works on Linux.
151    
152    17. Under certain error circumstances pcregrep might try to free random memory
153        as it exited. This is now fixed, thanks to valgrind.
154    
155    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
156        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
157        was because its rules for how to advance for /g after matching an empty
158        string at the end of a line did not allow for this case. They now check for
159        it specially.
160    
161    20. pcretest is supposed to handle patterns and data of any length, by
162        extending its buffers when necessary. It was getting this wrong when the
163        buffer for a data line had to be extended.
164    
165    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
166        CRLF as a newline sequence.
167    
168    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
169        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
170        I have nevertheless tidied it up.
171    
172    23. Added some casts to kill warnings from HP-UX ia64 compiler.
173    
174    24. Added a man page for pcre-config.
175    
176    
177    Version 7.0 19-Dec-06
178    ---------------------
179    
180     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
181        moving to gcc 4.1.1.
182    
183     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
184        sys/time.h, which is documented as needed for this function. It doesn't
185        seem to matter on Linux, but it showed up on some releases of OS X.
186    
187     3. It seems that there are systems where bytes whose values are greater than
188        127 match isprint() in the "C" locale. The "C" locale should be the
189        default when a C program starts up. In most systems, only ASCII printing
190        characters match isprint(). This difference caused the output from pcretest
191        to vary, making some of the tests fail. I have changed pcretest so that:
192    
193        (a) When it is outputting text in the compiled version of a pattern, bytes
194            other than 32-126 are always shown as hex escapes.
195    
196        (b) When it is outputting text that is a matched part of a subject string,
197            it does the same, unless a different locale has been set for the match
198            (using the /L modifier). In this case, it uses isprint() to decide.
199    
200     4. Fixed a major bug that caused incorrect computation of the amount of memory
201        required for a compiled pattern when options that changed within the
202        pattern affected the logic of the preliminary scan that determines the
203        length. The relevant options are -x, and -i in UTF-8 mode. The result was
204        that the computed length was too small. The symptoms of this bug were
205        either the PCRE error "internal error: code overflow" from pcre_compile(),
206        or a glibc crash with a message such as "pcretest: free(): invalid next
207        size (fast)". Examples of patterns that provoked this bug (shown in
208        pcretest format) are:
209    
210          /(?-x: )/x
211          /(?x)(?-x: \s*#\s*)/
212          /((?i)[\x{c0}])/8
213          /(?i:[\x{c0}])/8
214    
215        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
216        is now done differently.
217    
218     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
219        wrapper classes; (b) implement a new function in the C++ scanner that is
220        more efficient than the old way of doing things because it avoids levels of
221        recursion in the regex matching; (c) add a paragraph to the documentation
222        for the FullMatch() function.
223    
224     6. The escape sequence \n was being treated as whatever was defined as
225        "newline". Not only was this contrary to the documentation, which states
226        that \n is character 10 (hex 0A), but it also went horribly wrong when
227        "newline" was defined as CRLF. This has been fixed.
228    
229     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
230        was being set to -1 for the "end of line" case (supposedly a value that no
231        character can have). Though this value is never used (the check for end of
232        line is "zero bytes in current character"), it caused compiler complaints.
233        I've changed it to 0xffffffff.
234    
235     8. In pcre_version.c, the version string was being built by a sequence of
236        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
237        string (as it is for production releases) called a macro with an empty
238        argument. The C standard says the result of this is undefined. The gcc
239        compiler treats it as an empty string (which was what was wanted) but it is
240        reported that Visual C gives an error. The source has been hacked around to
241        avoid this problem.
242    
243     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
244        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
245        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
246        of them did).
247    
248    10. Originally, pcretest opened its input and output without "b"; then I was
249        told that "b" was needed in some environments, so it was added for release
250        5.0 to both the input and output. (It makes no difference on Unix-like
251        systems.) Later I was told that it is wrong for the input on Windows. I've
252        now abstracted the modes into two macros, to make it easier to fiddle with
253        them, and removed "b" from the input mode under Windows.
254    
255    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
256    
257    12. Added -help and --help to pcretest as an official way of being reminded
258        of the options.
259    
260    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
261        and pcrecpp.cc because they annoy compilers at high warning levels.
262    
263    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
264    
265    15. Fixed an occurrence of == in configure.ac that should have been = (shell
266        scripts are not C programs :-) and which was not noticed because it works
267        on Linux.
268    
269    16. pcretest is supposed to handle any length of pattern and data line (as one
270        line or as a continued sequence of lines) by extending its input buffer if
271        necessary. This feature was broken for very long pattern lines, leading to
272        a string of junk being passed to pcre_compile() if the pattern was longer
273        than about 50K.
274    
275    17. I have done a major re-factoring of the way pcre_compile() computes the
276        amount of memory needed for a compiled pattern. Previously, there was code
277        that made a preliminary scan of the pattern in order to do this. That was
278        OK when PCRE was new, but as the facilities have expanded, it has become
279        harder and harder to keep it in step with the real compile phase, and there
280        have been a number of bugs (see for example, 4 above). I have now found a
281        cunning way of running the real compile function in a "fake" mode that
282        enables it to compute how much memory it would need, while actually only
283        ever using a few hundred bytes of working memory and without too many
284        tests of the mode. This should make future maintenance and development
285        easier. A side effect of this work is that the limit of 200 on the nesting
286        depth of parentheses has been removed (though this was never a serious
287        limitation, I suspect). However, there is a downside: pcre_compile() now
288        runs more slowly than before (30% or more, depending on the pattern). I
289        hope this isn't a big issue. There is no effect on runtime performance.
290    
291    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
292        newline (only possible for the last line of a file) and it was a
293        pattern that set a locale (followed by /Lsomething), pcretest crashed.
294    
295    19. Added additional timing features to pcretest. (1) The -tm option now times
296        matching only, not compiling. (2) Both -t and -tm can be followed, as a
297        separate command line item, by a number that specifies the number of
298        repeats to use when timing. The default is 50000; this gives better
299        precision, but takes uncomfortably long for very large patterns.
300    
301    20. Extended pcre_study() to be more clever in cases where a branch of a
302        subpattern has no definite first character. For example, (a*|b*)[cd] would
303        previously give no result from pcre_study(). Now it recognizes that the
304        first character must be a, b, c, or d.
305    
306    21. There was an incorrect error "recursive call could loop indefinitely" if
307        a subpattern (or the entire pattern) that was being tested for matching an
308        empty string contained only one non-empty item after a nested subpattern.
309        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
310        incorrectly, because the \d was being skipped in the check.
311    
312    22. The pcretest program now has a new pattern option /B and a command line
313        option -b, which is equivalent to adding /B to every pattern. This causes
314        it to show the compiled bytecode, without the additional information that
315        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
316        is the same as /B/I).
317    
318    23. A new optimization is now able automatically to treat some sequences such
319        as a*b as a*+b. More specifically, if something simple (such as a character
320        or a simple class like \d) has an unlimited quantifier, and is followed by
321        something that cannot possibly match the quantified thing, the quantifier
322        is automatically "possessified".
323    
324    24. A recursive reference to a subpattern whose number was greater than 39
325        went wrong under certain circumstances in UTF-8 mode. This bug could also
326        have affected the operation of pcre_study().
327    
328    25. Realized that a little bit of performance could be had by replacing
329        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
330    
331    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
332    
333    27. Possessive quantifiers such as a++ were previously implemented by turning
334        them into atomic groups such as ($>a+). Now they have their own opcodes,
335        which improves performance. This includes the automatically created ones
336        from 23 above.
337    
338    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
339        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
340        the first matched character to be a colon. This applied both to named and
341        numbered groups.
342    
343    29. The ucpinternal.h header file was missing its idempotency #ifdef.
344    
345    30. I was sent a "project" file called libpcre.a.dev which I understand makes
346        building PCRE on Windows easier, so I have included it in the distribution.
347    
348    31. There is now a check in pcretest against a ridiculously large number being
349        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
350        loop, the loop is abandoned.
351    
352    32. Forward references to subpatterns in conditions such as (?(2)...) where
353        subpattern 2 is defined later cause pcre_compile() to search forwards in
354        the pattern for the relevant set of parentheses. This search went wrong
355        when there were unescaped parentheses in a character class, parentheses
356        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
357    
358    33. "Subroutine" calls and backreferences were previously restricted to
359        referencing subpatterns earlier in the regex. This restriction has now
360        been removed.
361    
362    34. Added a number of extra features that are going to be in Perl 5.10. On the
363        whole, these are just syntactic alternatives for features that PCRE had
364        previously implemented using the Python syntax or my own invention. The
365        other formats are all retained for compatibility.
366    
367        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
368            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
369            also .NET compatible.
370    
371        (b) A recursion or subroutine call to a named group can now be defined as
372            (?&name) as well as (?P>name).
373    
374        (c) A backreference to a named group can now be defined as \k<name> or
375            \k'name' as well as (?P=name). The new forms, as well as being in Perl
376            5.10, are also .NET compatible.
377    
378        (d) A conditional reference to a named group can now use the syntax
379            (?(<name>) or (?('name') as well as (?(name).
380    
381        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
382            groups (named and numbered) that are never evaluated inline, but can be
383            called as "subroutines" from elsewhere. In effect, the DEFINE condition
384            is always false. There may be only one alternative in such a group.
385    
386        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
387            as the simple (?(R). The condition is true only if the most recent
388            recursion is that of the given number or name. It does not search out
389            through the entire recursion stack.
390    
391        (g) The escape \gN or \g{N} has been added, where N is a positive or
392            negative number, specifying an absolute or relative reference.
393    
394    35. Tidied to get rid of some further signed/unsigned compiler warnings and
395        some "unreachable code" warnings.
396    
397    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
398        things, this adds five new scripts.
399    
400    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
401        There were also incompatibilities regarding the handling of \Q..\E inside
402        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
403        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
404    
405    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
406        matches an empty string, and forcibly breaks the loop. There were bugs in
407        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
408        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
409        separate and independent bugs (that affected different cases) have been
410        fixed.
411    
412    39. Refactored the code to abolish the use of different opcodes for small
413        capturing bracket numbers. This is a tidy that I avoided doing when I
414        removed the limit on the number of capturing brackets for 3.5 back in 2001.
415        The new approach is not only tidier, it makes it possible to reduce the
416        memory needed to fix the previous bug (38).
417    
418    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
419        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
420        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
421        mode.
422    
423    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
424        report.
425    
426    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
427        copy construction and assignment in the C++ wrapper.
428    
429    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
430        couple of bugs that could have given wrong results in the "--newline=crlf"
431        case.
432    
433    44. Added a number of casts and did some reorganization of signed/unsigned int
434        variables following suggestions from Dair Grant. Also renamed the variable
435        "this" as "item" because it is a C++ keyword.
436    
437    45. Arranged for dftables to add
438    
439          #include "pcre_internal.h"
440    
441        to pcre_chartables.c because without it, gcc 4.x may remove the array
442        definition from the final binary if PCRE is built into a static library and
443        dead code stripping is activated.
444    
445    46. For an unanchored pattern, if a match attempt fails at the start of a
446        newline sequence, and the newline setting is CRLF or ANY, and the next two
447        characters are CRLF, advance by two characters instead of one.
448    
449    
450  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
451  ---------------------  ---------------------
452    

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