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

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