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revision 85 by nigel, Sat Feb 24 21:41:13 2007 UTC revision 223 by ph10, Mon Aug 20 11:07:53 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 20-Aug-07
5    ---------------------
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
13          #include "pcre.h"
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
35     6. ESC_K was left out of the EBCDIC table.
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
94    14. Optimized (?!) to (*FAIL).
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
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).
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.)
120    21. An orphan \E inside a character class could cause a crash.
122    22. A repeated capturing bracket such as (A)? could cause a wild memory
123        reference during compilation.
125    23. There are several functions in pcre_compile() that scan along a compiled
126        expression for various reasons (e.g. to see if it's fixed length for look
127        behind). There were bugs in these functions when a repeated \p or \P was
128        present in the pattern. These operators have additional parameters compared
129        with \d, etc, and these were not being taken into account when moving along
130        the compiled data. Specifically:
132        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
133            length.
135        (b) An item such as \pL+ within a repeated group could cause crashes or
136            loops.
138        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
139            "reference to non-existent subpattern" error.
141        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
143    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
144        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
146    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
148    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
149        character were causing crashes (broken optimization).
152    Version 7.2 19-Jun-07
153    ---------------------
155     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
156        which is apparently normally available under Windows.
158     2. Re-jig the pcregrep tests with different newline settings in an attempt
159        to make them independent of the local environment's newline setting.
161     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
163     4. Some of the "internals" tests were previously cut out when the link size
164        was not 2, because the output contained actual offsets. The recent new
165        "Z" feature of pcretest means that these can be cut out, making the tests
166        usable with all link sizes.
168     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
169        stack recursion. This gives a massive performance boost under BSD, but just
170        a small improvement under Linux. However, it saves one field in the frame
171        in all cases.
173     6. Added more features from the forthcoming Perl 5.10:
175        (a) (?-n) (where n is a string of digits) is a relative subroutine or
176            recursion call. It refers to the nth most recently opened parentheses.
178        (b) (?+n) is also a relative subroutine call; it refers to the nth next
179            to be opened parentheses.
181        (c) Conditions that refer to capturing parentheses can be specified
182            relatively, for example, (?(-2)... or (?(+3)...
184        (d) \K resets the start of the current match so that everything before
185            is not part of it.
187        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
189        (f) \g{name} is another synonym - part of Perl 5.10's unification of
190            reference syntax.
192        (g) (?| introduces a group in which the numbering of parentheses in each
193            alternative starts with the same number.
195        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
197     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
200     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
201        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
202        for detecting groups that can match an empty string.
204     9. A pattern with a very large number of alternatives (more than several
205        hundred) was running out of internal workspace during the pre-compile
206        phase, where pcre_compile() figures out how much memory will be needed. A
207        bit of new cunning has reduced the workspace needed for groups with
208        alternatives. The 1000-alternative test pattern now uses 12 bytes of
209        workspace instead of running out of the 4096 that are available.
211    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
213    11. Applied patch from Google to remove an optimization that didn't quite work.
214        The report of the bug said:
216          pcrecpp::RE("a*").FullMatch("aaa") matches, while
217          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
218          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
220    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
221        it matched the wrong number of bytes.
224    Version 7.1 24-Apr-07
225    ---------------------
227     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
228        that is more "standard", making use of automake and other Autotools. There
229        is some re-arrangement of the files and adjustment of comments consequent
230        on this.
232     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
233        for recursive directory scanning broke on some systems because the files
234        are not scanned in any specific order and on different systems the order
235        was different. A call to "sort" has been inserted into RunGrepTest for the
236        approprate test as a short-term fix. In the longer term there may be an
237        alternative.
239     3. I had an email from Eric Raymond about problems translating some of PCRE's
240        man pages to HTML (despite the fact that I distribute HTML pages, some
241        people do their own conversions for various reasons). The problems
242        concerned the use of low-level troff macros .br and .in. I have therefore
243        removed all such uses from the man pages (some were redundant, some could
244        be replaced by .nf/.fi pairs). The 132html script that I use to generate
245        HTML has been updated to handle .nf/.fi and to complain if it encounters
246        .br or .in.
248     4. Updated comments in configure.ac that get placed in config.h.in and also
249        arranged for config.h to be included in the distribution, with the name
250        config.h.generic, for the benefit of those who have to compile without
251        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
253     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
254        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
255        makevp.bat for the current PCRE, using the additional files
256        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
258     6. A Windows user reported a minor discrepancy with test 2, which turned out
259        to be caused by a trailing space on an input line that had got lost in his
260        copy. The trailing space was an accident, so I've just removed it.
262     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
263        that is needed.
265     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
266        as "const" (a) because they are and (b) because it helps the PHP
267        maintainers who have recently made a script to detect big data structures
268        in the php code that should be moved to the .rodata section. I remembered
269        to update Builducptable as well, so it won't revert if ucptable.h is ever
270        re-created.
272     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
273        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
274        order to be able to cut out the UTF-8 tables in the latter when UTF-8
275        support is not required. This saves 1.5-2K of code, which is important in
276        some applications.
278        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
279        so as not to refer to the tables, even though these functions will never be
280        called when UTF-8 support is disabled. Otherwise there are problems with a
281        shared library.
283    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
285        (a) It was defining its arguments as char * instead of void *.
287        (b) It was assuming that all moves were upwards in memory; this was true
288            a long time ago when I wrote it, but is no longer the case.
290        The emulated memove() is provided for those environments that have neither
291        memmove() nor bcopy(). I didn't think anyone used it these days, but that
292        is clearly not the case, as these two bugs were recently reported.
294    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
295        and Detrail to create the HTML documentation, the .txt form of the man
296        pages, and it removes trailing spaces from listed files. It also creates
297        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
298        case, it wraps all the #defines with #ifndefs. This script should be run
299        before "make dist".
301    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
302        with Unicode property support.
304        (a) For a maximizing quantifier, if the two different cases of the
305            character were of different lengths in their UTF-8 codings (there are
306            some cases like this - I found 11), and the matching function had to
307            back up over a mixture of the two cases, it incorrectly assumed they
308            were both the same length.
310        (b) When PCRE was configured to use the heap rather than the stack for
311            recursion during matching, it was not correctly preserving the data for
312            the other case of a UTF-8 character when checking ahead for a match
313            while processing a minimizing repeat. If the check also involved
314            matching a wide character, but failed, corruption could cause an
315            erroneous result when trying to check for a repeat of the original
316            character.
318    13. Some tidying changes to the testing mechanism:
320        (a) The RunTest script now detects the internal link size and whether there
321            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
322            values substituted by "configure". (The RunGrepTest script already did
323            this for UTF-8.) The configure.ac script no longer substitutes the
324            relevant variables.
326        (b) The debugging options /B and /D in pcretest show the compiled bytecode
327            with length and offset values. This means that the output is different
328            for different internal link sizes. Test 2 is skipped for link sizes
329            other than 2 because of this, bypassing the problem. Unfortunately,
330            there was also a test in test 3 (the locale tests) that used /B and
331            failed for link sizes other than 2. Rather than cut the whole test out,
332            I have added a new /Z option to pcretest that replaces the length and
333            offset values with spaces. This is now used to make test 3 independent
334            of link size. (Test 2 will be tidied up later.)
336    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
337        segmentation fault instead of returning the appropriate error message.
339    15. In multiline mode when the newline sequence was set to "any", the pattern
340        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
341        This doesn't seem right; it now treats the CRLF combination as the line
342        ending, and so does not match in that case. It's only a pattern such as ^$
343        that would hit this one: something like ^ABC$ would have failed after \r
344        and then tried again after \r\n.
346    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
347        in an attempt to make files that differ only in their line terminators
348        compare equal. This works on Linux.
350    17. Under certain error circumstances pcregrep might try to free random memory
351        as it exited. This is now fixed, thanks to valgrind.
353    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
354        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
355        was because its rules for how to advance for /g after matching an empty
356        string at the end of a line did not allow for this case. They now check for
357        it specially.
359    20. pcretest is supposed to handle patterns and data of any length, by
360        extending its buffers when necessary. It was getting this wrong when the
361        buffer for a data line had to be extended.
363    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
364        CRLF as a newline sequence.
366    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
367        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
368        I have nevertheless tidied it up.
370    23. Added some casts to kill warnings from HP-UX ia64 compiler.
372    24. Added a man page for pcre-config.
375    Version 7.0 19-Dec-06
376    ---------------------
378     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
379        moving to gcc 4.1.1.
381     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
382        sys/time.h, which is documented as needed for this function. It doesn't
383        seem to matter on Linux, but it showed up on some releases of OS X.
385     3. It seems that there are systems where bytes whose values are greater than
386        127 match isprint() in the "C" locale. The "C" locale should be the
387        default when a C program starts up. In most systems, only ASCII printing
388        characters match isprint(). This difference caused the output from pcretest
389        to vary, making some of the tests fail. I have changed pcretest so that:
391        (a) When it is outputting text in the compiled version of a pattern, bytes
392            other than 32-126 are always shown as hex escapes.
394        (b) When it is outputting text that is a matched part of a subject string,
395            it does the same, unless a different locale has been set for the match
396            (using the /L modifier). In this case, it uses isprint() to decide.
398     4. Fixed a major bug that caused incorrect computation of the amount of memory
399        required for a compiled pattern when options that changed within the
400        pattern affected the logic of the preliminary scan that determines the
401        length. The relevant options are -x, and -i in UTF-8 mode. The result was
402        that the computed length was too small. The symptoms of this bug were
403        either the PCRE error "internal error: code overflow" from pcre_compile(),
404        or a glibc crash with a message such as "pcretest: free(): invalid next
405        size (fast)". Examples of patterns that provoked this bug (shown in
406        pcretest format) are:
408          /(?-x: )/x
409          /(?x)(?-x: \s*#\s*)/
410          /((?i)[\x{c0}])/8
411          /(?i:[\x{c0}])/8
413        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
414        is now done differently.
416     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
417        wrapper classes; (b) implement a new function in the C++ scanner that is
418        more efficient than the old way of doing things because it avoids levels of
419        recursion in the regex matching; (c) add a paragraph to the documentation
420        for the FullMatch() function.
422     6. The escape sequence \n was being treated as whatever was defined as
423        "newline". Not only was this contrary to the documentation, which states
424        that \n is character 10 (hex 0A), but it also went horribly wrong when
425        "newline" was defined as CRLF. This has been fixed.
427     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
428        was being set to -1 for the "end of line" case (supposedly a value that no
429        character can have). Though this value is never used (the check for end of
430        line is "zero bytes in current character"), it caused compiler complaints.
431        I've changed it to 0xffffffff.
433     8. In pcre_version.c, the version string was being built by a sequence of
434        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
435        string (as it is for production releases) called a macro with an empty
436        argument. The C standard says the result of this is undefined. The gcc
437        compiler treats it as an empty string (which was what was wanted) but it is
438        reported that Visual C gives an error. The source has been hacked around to
439        avoid this problem.
441     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
442        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
443        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
444        of them did).
446    10. Originally, pcretest opened its input and output without "b"; then I was
447        told that "b" was needed in some environments, so it was added for release
448        5.0 to both the input and output. (It makes no difference on Unix-like
449        systems.) Later I was told that it is wrong for the input on Windows. I've
450        now abstracted the modes into two macros, to make it easier to fiddle with
451        them, and removed "b" from the input mode under Windows.
453    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
455    12. Added -help and --help to pcretest as an official way of being reminded
456        of the options.
458    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
459        and pcrecpp.cc because they annoy compilers at high warning levels.
461    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
463    15. Fixed an occurrence of == in configure.ac that should have been = (shell
464        scripts are not C programs :-) and which was not noticed because it works
465        on Linux.
467    16. pcretest is supposed to handle any length of pattern and data line (as one
468        line or as a continued sequence of lines) by extending its input buffer if
469        necessary. This feature was broken for very long pattern lines, leading to
470        a string of junk being passed to pcre_compile() if the pattern was longer
471        than about 50K.
473    17. I have done a major re-factoring of the way pcre_compile() computes the
474        amount of memory needed for a compiled pattern. Previously, there was code
475        that made a preliminary scan of the pattern in order to do this. That was
476        OK when PCRE was new, but as the facilities have expanded, it has become
477        harder and harder to keep it in step with the real compile phase, and there
478        have been a number of bugs (see for example, 4 above). I have now found a
479        cunning way of running the real compile function in a "fake" mode that
480        enables it to compute how much memory it would need, while actually only
481        ever using a few hundred bytes of working memory and without too many
482        tests of the mode. This should make future maintenance and development
483        easier. A side effect of this work is that the limit of 200 on the nesting
484        depth of parentheses has been removed (though this was never a serious
485        limitation, I suspect). However, there is a downside: pcre_compile() now
486        runs more slowly than before (30% or more, depending on the pattern). I
487        hope this isn't a big issue. There is no effect on runtime performance.
489    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
490        newline (only possible for the last line of a file) and it was a
491        pattern that set a locale (followed by /Lsomething), pcretest crashed.
493    19. Added additional timing features to pcretest. (1) The -tm option now times
494        matching only, not compiling. (2) Both -t and -tm can be followed, as a
495        separate command line item, by a number that specifies the number of
496        repeats to use when timing. The default is 50000; this gives better
497        precision, but takes uncomfortably long for very large patterns.
499    20. Extended pcre_study() to be more clever in cases where a branch of a
500        subpattern has no definite first character. For example, (a*|b*)[cd] would
501        previously give no result from pcre_study(). Now it recognizes that the
502        first character must be a, b, c, or d.
504    21. There was an incorrect error "recursive call could loop indefinitely" if
505        a subpattern (or the entire pattern) that was being tested for matching an
506        empty string contained only one non-empty item after a nested subpattern.
507        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
508        incorrectly, because the \d was being skipped in the check.
510    22. The pcretest program now has a new pattern option /B and a command line
511        option -b, which is equivalent to adding /B to every pattern. This causes
512        it to show the compiled bytecode, without the additional information that
513        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
514        is the same as /B/I).
516    23. A new optimization is now able automatically to treat some sequences such
517        as a*b as a*+b. More specifically, if something simple (such as a character
518        or a simple class like \d) has an unlimited quantifier, and is followed by
519        something that cannot possibly match the quantified thing, the quantifier
520        is automatically "possessified".
522    24. A recursive reference to a subpattern whose number was greater than 39
523        went wrong under certain circumstances in UTF-8 mode. This bug could also
524        have affected the operation of pcre_study().
526    25. Realized that a little bit of performance could be had by replacing
527        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
529    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
531    27. Possessive quantifiers such as a++ were previously implemented by turning
532        them into atomic groups such as ($>a+). Now they have their own opcodes,
533        which improves performance. This includes the automatically created ones
534        from 23 above.
536    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
537        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
538        the first matched character to be a colon. This applied both to named and
539        numbered groups.
541    29. The ucpinternal.h header file was missing its idempotency #ifdef.
543    30. I was sent a "project" file called libpcre.a.dev which I understand makes
544        building PCRE on Windows easier, so I have included it in the distribution.
546    31. There is now a check in pcretest against a ridiculously large number being
547        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
548        loop, the loop is abandoned.
550    32. Forward references to subpatterns in conditions such as (?(2)...) where
551        subpattern 2 is defined later cause pcre_compile() to search forwards in
552        the pattern for the relevant set of parentheses. This search went wrong
553        when there were unescaped parentheses in a character class, parentheses
554        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
556    33. "Subroutine" calls and backreferences were previously restricted to
557        referencing subpatterns earlier in the regex. This restriction has now
558        been removed.
560    34. Added a number of extra features that are going to be in Perl 5.10. On the
561        whole, these are just syntactic alternatives for features that PCRE had
562        previously implemented using the Python syntax or my own invention. The
563        other formats are all retained for compatibility.
565        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
566            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
567            also .NET compatible.
569        (b) A recursion or subroutine call to a named group can now be defined as
570            (?&name) as well as (?P>name).
572        (c) A backreference to a named group can now be defined as \k<name> or
573            \k'name' as well as (?P=name). The new forms, as well as being in Perl
574            5.10, are also .NET compatible.
576        (d) A conditional reference to a named group can now use the syntax
577            (?(<name>) or (?('name') as well as (?(name).
579        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
580            groups (named and numbered) that are never evaluated inline, but can be
581            called as "subroutines" from elsewhere. In effect, the DEFINE condition
582            is always false. There may be only one alternative in such a group.
584        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
585            as the simple (?(R). The condition is true only if the most recent
586            recursion is that of the given number or name. It does not search out
587            through the entire recursion stack.
589        (g) The escape \gN or \g{N} has been added, where N is a positive or
590            negative number, specifying an absolute or relative reference.
592    35. Tidied to get rid of some further signed/unsigned compiler warnings and
593        some "unreachable code" warnings.
595    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
596        things, this adds five new scripts.
598    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
599        There were also incompatibilities regarding the handling of \Q..\E inside
600        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
601        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
603    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
604        matches an empty string, and forcibly breaks the loop. There were bugs in
605        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
606        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
607        separate and independent bugs (that affected different cases) have been
608        fixed.
610    39. Refactored the code to abolish the use of different opcodes for small
611        capturing bracket numbers. This is a tidy that I avoided doing when I
612        removed the limit on the number of capturing brackets for 3.5 back in 2001.
613        The new approach is not only tidier, it makes it possible to reduce the
614        memory needed to fix the previous bug (38).
616    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
617        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
618        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
619        mode.
621    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
622        report.
624    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
625        copy construction and assignment in the C++ wrapper.
627    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
628        couple of bugs that could have given wrong results in the "--newline=crlf"
629        case.
631    44. Added a number of casts and did some reorganization of signed/unsigned int
632        variables following suggestions from Dair Grant. Also renamed the variable
633        "this" as "item" because it is a C++ keyword.
635    45. Arranged for dftables to add
637          #include "pcre_internal.h"
639        to pcre_chartables.c because without it, gcc 4.x may remove the array
640        definition from the final binary if PCRE is built into a static library and
641        dead code stripping is activated.
643    46. For an unanchored pattern, if a match attempt fails at the start of a
644        newline sequence, and the newline setting is CRLF or ANY, and the next two
645        characters are CRLF, advance by two characters instead of one.
648    Version 6.7 04-Jul-06
649    ---------------------
651     1. In order to handle tests when input lines are enormously long, pcretest has
652        been re-factored so that it automatically extends its buffers when
653        necessary. The code is crude, but this _is_ just a test program. The
654        default size has been increased from 32K to 50K.
656     2. The code in pcre_study() was using the value of the re argument before
657        testing it for NULL. (Of course, in any sensible call of the function, it
658        won't be NULL.)
660     3. The memmove() emulation function in pcre_internal.h, which is used on
661        systems that lack both memmove() and bcopy() - that is, hardly ever -
662        was missing a "static" storage class specifier.
664     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
665        containing an extended class (one that cannot be represented by a bitmap
666        because it contains high-valued characters or Unicode property items, e.g.
667        [\pZ]). Almost always one would set UTF-8 mode when processing such a
668        pattern, but PCRE should not loop if you do not (it no longer does).
669        [Detail: two cases were found: (a) a repeated subpattern containing an
670        extended class; (b) a recursive reference to a subpattern that followed a
671        previous extended class. It wasn't skipping over the extended class
672        correctly when UTF-8 mode was not set.]
674     5. A negated single-character class was not being recognized as fixed-length
675        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
676        compile error "lookbehind assertion is not fixed length".
678     6. The RunPerlTest auxiliary script was showing an unexpected difference
679        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
680        write a Perl script that can interpret lines of an input file either as
681        byte characters or as UTF-8, which is what "perltest" was being required to
682        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
683        can't do is switch easily at run time between having the "use utf8;" pragma
684        or not. In the end, I fudged it by using the RunPerlTest script to insert
685        "use utf8;" explicitly for the UTF-8 tests.
687     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
688        the end of the subject string, contrary to the documentation and to what
689        Perl does. This was true of both matching functions. Now it matches only at
690        the start of the subject and immediately after *internal* newlines.
692     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
693        a pointer to an int instead of a pointer to an unsigned long int. This
694        caused problems on 64-bit systems.
696     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
697        instance of the 'standard' template library not being so standard".
699    10. There was no check on the number of named subpatterns nor the maximum
700        length of a subpattern name. The product of these values is used to compute
701        the size of the memory block for a compiled pattern. By supplying a very
702        long subpattern name and a large number of named subpatterns, the size
703        computation could be caused to overflow. This is now prevented by limiting
704        the length of names to 32 characters, and the number of named subpatterns
705        to 10,000.
707    11. Subpatterns that are repeated with specific counts have to be replicated in
708        the compiled pattern. The size of memory for this was computed from the
709        length of the subpattern and the repeat count. The latter is limited to
710        65535, but there was no limit on the former, meaning that integer overflow
711        could in principle occur. The compiled length of a repeated subpattern is
712        now limited to 30,000 bytes in order to prevent this.
714    12. Added the optional facility to have named substrings with the same name.
716    13. Added the ability to use a named substring as a condition, using the
717        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
718        are numbers (not recommended). Forward references are permitted.
720    14. Added forward references in named backreferences (if you see what I mean).
722    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
723        pattern could run off the end of the subject. For example, the pattern
724        "(?s)(.{1,5})"8 did this with the subject "ab".
726    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
727        PCRE_CASELESS was set when matching characters that were quantified with ?
728        or *.
730    17. A character class other than a single negated character that had a minimum
731        but no maximum quantifier - for example [ab]{6,} - was not handled
732        correctly by pce_dfa_exec(). It would match only one character.
734    18. A valid (though odd) pattern that looked like a POSIX character
735        class but used an invalid character after [ (for example [[,abc,]]) caused
736        pcre_compile() to give the error "Failed: internal error: code overflow" or
737        in some cases to crash with a glibc free() error. This could even happen if
738        the pattern terminated after [[ but there just happened to be a sequence of
739        letters, a binary zero, and a closing ] in the memory that followed.
741    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
742        over the years. Originally (before any Unicode support), just the bottom 8
743        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
744        output from "man perlunicode" includes this:
746          The regular expression compiler produces polymorphic opcodes.  That
747          is, the pattern adapts to the data and automatically switches to
748          the Unicode character scheme when presented with Unicode data--or
749          instead uses a traditional byte scheme when presented with byte
750          data.
752        Sadly, a wide octal escape does not cause a switch, and in a string with
753        no other multibyte characters, these octal escapes are treated as before.
754        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
755        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
756        Unicode string.
758        I have not perpetrated such confusion in PCRE. Up till now, it took just
759        the bottom 8 bits, as in old Perl. I have now made octal escapes with
760        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
761        translate to the appropriate multibyte character.
763    29. Applied some refactoring to reduce the number of warnings from Microsoft
764        and Borland compilers. This has included removing the fudge introduced
765        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
766        a warning about an unused variable.
768    21. PCRE has not included VT (character 0x0b) in the set of whitespace
769        characters since release 4.0, because Perl (from release 5.004) does not.
770        [Or at least, is documented not to: some releases seem to be in conflict
771        with the documentation.] However, when a pattern was studied with
772        pcre_study() and all its branches started with \s, PCRE still included VT
773        as a possible starting character. Of course, this did no harm; it just
774        caused an unnecessary match attempt.
776    22. Removed a now-redundant internal flag bit that recorded the fact that case
777        dependency changed within the pattern. This was once needed for "required
778        byte" processing, but is no longer used. This recovers a now-scarce options
779        bit. Also moved the least significant internal flag bit to the most-
780        significant bit of the word, which was not previously used (hangover from
781        the days when it was an int rather than a uint) to free up another bit for
782        the future.
784    23. Added support for CRLF line endings as well as CR and LF. As well as the
785        default being selectable at build time, it can now be changed at runtime
786        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
787        specify that it is scanning data with non-default line endings.
789    24. Changed the definition of CXXLINK to make it agree with the definition of
790        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
792    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
793        recursions. This makes a big different to stack usage for some patterns.
795    26. If a subpattern containing a named recursion or subroutine reference such
796        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
797        the space required for the compiled pattern went wrong and gave too small a
798        value. Depending on the environment, this could lead to "Failed: internal
799        error: code overflow at offset 49" or "glibc detected double free or
800        corruption" errors.
802    27. Applied patches from Google (a) to support the new newline modes and (b) to
803        advance over multibyte UTF-8 characters in GlobalReplace.
805    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
806        difference for some implementation of PCRE in some Windows version.
808    29. Added some extra testing facilities to pcretest:
810        \q<number>   in a data line sets the "match limit" value
811        \Q<number>   in a data line sets the "match recursion limt" value
812        -S <number>  sets the stack size, where <number> is in megabytes
814        The -S option isn't available for Windows.
817    Version 6.6 06-Feb-06
818    ---------------------
820     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
821        in pcreposix.h. I have copied the definition from pcre.h.
823     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
824        because pcre.h is no longer a built file.
826     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
827        not normally included in the compiled code.
830    Version 6.5 01-Feb-06
831    ---------------------
833     1. When using the partial match feature with pcre_dfa_exec(), it was not
834        anchoring the second and subsequent partial matches at the new starting
835        point. This could lead to incorrect results. For example, with the pattern
836        /1234/, partially matching against "123" and then "a4" gave a match.
838     2. Changes to pcregrep:
840        (a) All non-match returns from pcre_exec() were being treated as failures
841            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
842            error message is output. Some extra information is given for the
843            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
844            probably the only errors that are likely to be caused by users (by
845            specifying a regex that has nested indefinite repeats, for instance).
846            If there are more than 20 of these errors, pcregrep is abandoned.
848        (b) A binary zero was treated as data while matching, but terminated the
849            output line if it was written out. This has been fixed: binary zeroes
850            are now no different to any other data bytes.
852        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
853            used to set a locale for matching. The --locale=xxxx long option has
854            been added (no short equivalent) to specify a locale explicitly on the
855            pcregrep command, overriding the environment variables.
857        (d) When -B was used with -n, some line numbers in the output were one less
858            than they should have been.
860        (e) Added the -o (--only-matching) option.
862        (f) If -A or -C was used with -c (count only), some lines of context were
863            accidentally printed for the final match.
865        (g) Added the -H (--with-filename) option.
867        (h) The combination of options -rh failed to suppress file names for files
868            that were found from directory arguments.
870        (i) Added the -D (--devices) and -d (--directories) options.
872        (j) Added the -F (--fixed-strings) option.
874        (k) Allow "-" to be used as a file name for -f as well as for a data file.
876        (l) Added the --colo(u)r option.
878        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
879            is not present by default.
881     3. A nasty bug was discovered in the handling of recursive patterns, that is,
882        items such as (?R) or (?1), when the recursion could match a number of
883        alternatives. If it matched one of the alternatives, but subsequently,
884        outside the recursion, there was a failure, the code tried to back up into
885        the recursion. However, because of the way PCRE is implemented, this is not
886        possible, and the result was an incorrect result from the match.
888        In order to prevent this happening, the specification of recursion has
889        been changed so that all such subpatterns are automatically treated as
890        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
892     4. I had overlooked the fact that, in some locales, there are characters for
893        which isalpha() is true but neither isupper() nor islower() are true. In
894        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
895        and ordfeminine) are like this. This affected the treatment of \w and \W
896        when they appeared in character classes, but not when they appeared outside
897        a character class. The bit map for "word" characters is now created
898        separately from the results of isalnum() instead of just taking it from the
899        upper, lower, and digit maps. (Plus the underscore character, of course.)
901     5. The above bug also affected the handling of POSIX character classes such as
902        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
903        permanent tables. Instead, the bit maps for such a class were previously
904        created as the appropriate unions of the upper, lower, and digit bitmaps.
905        Now they are created by subtraction from the [[:word:]] class, which has
906        its own bitmap.
908     6. The [[:blank:]] character class matches horizontal, but not vertical space.
909        It is created by subtracting the vertical space characters (\x09, \x0a,
910        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
911        subtraction was done in the overall bitmap for a character class, meaning
912        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
913        be recognized. This bug has been fixed.
915     7. Patches from the folks at Google:
917          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
918          real life, but is still worth protecting against".
920          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
921          regular expressions".
923          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
924          have it.
926          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
927          "configure" and the latter not, in order to fix a problem somebody had
928          with compiling the Arg class on HP-UX.
930          (e) Improve the error-handling of the C++ wrapper a little bit.
932          (f) New tests for checking recursion limiting.
934     8. The pcre_memmove() function, which is used only if the environment does not
935        have a standard memmove() function (and is therefore rarely compiled),
936        contained two bugs: (a) use of int instead of size_t, and (b) it was not
937        returning a result (though PCRE never actually uses the result).
939     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
940        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
941        returned instead of calling malloc() with an overflowing number that would
942        most likely cause subsequent chaos.
944    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
946    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
947        with this option is matched, the nmatch and pmatch options of regexec() are
948        ignored.
950    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
951        provided in case anyone wants to the the POSIX interface with UTF-8
952        strings.
954    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
955        C++ linking (needed for some HP-UX environments).
957    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
958        (unused parameter) and in the pcre_printint() function (omitted "default"
959        switch label when the default is to do nothing).
961    15. Added some code to make it possible, when PCRE is compiled as a C++
962        library, to replace subject pointers for pcre_exec() with a smart pointer
963        class, thus making it possible to process discontinuous strings.
965    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
966        much the same function. They were added by different people who were trying
967        to make PCRE easy to compile on non-Unix systems. It has been suggested
968        that PCRE_EXPORT be abolished now that there is more automatic apparatus
969        for compiling on Windows systems. I have therefore replaced it with
970        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
971        defaults to "extern" for C or "extern C" for C++, which works fine on
972        Unix-like systems. It is now possible to override the value of PCRE_DATA_
973        SCOPE with something explicit in config.h. In addition:
975        (a) pcreposix.h still had just "extern" instead of either of these macros;
976            I have replaced it with PCRE_DATA_SCOPE.
978        (b) Functions such as _pcre_xclass(), which are internal to the library,
979            but external in the C sense, all had PCRE_EXPORT in their definitions.
980            This is apparently wrong for the Windows case, so I have removed it.
981            (It makes no difference on Unix-like systems.)
983    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
984        of recursive calls to match(). This is different to MATCH_LIMIT because
985        that limits the total number of calls to match(), not all of which increase
986        the depth of recursion. Limiting the recursion depth limits the amount of
987        stack (or heap if NO_RECURSE is set) that is used. The default can be set
988        when PCRE is compiled, and changed at run time. A patch from Google adds
989        this functionality to the C++ interface.
991    18. Changes to the handling of Unicode character properties:
993        (a) Updated the table to Unicode 4.1.0.
995        (b) Recognize characters that are not in the table as "Cn" (undefined).
997        (c) I revised the way the table is implemented to a much improved format
998            which includes recognition of ranges. It now supports the ranges that
999            are defined in UnicodeData.txt, and it also amalgamates other
1000            characters into ranges. This has reduced the number of entries in the
1001            table from around 16,000 to around 3,000, thus reducing its size
1002            considerably. I realized I did not need to use a tree structure after
1003            all - a binary chop search is just as efficient. Having reduced the
1004            number of entries, I extended their size from 6 bytes to 8 bytes to
1005            allow for more data.
1007        (d) Added support for Unicode script names via properties such as \p{Han}.
1009    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1010        matching that character.
1012    20. When matching a repeated Unicode property with a minimum greater than zero,
1013        (for example \pL{2,}), PCRE could look past the end of the subject if it
1014        reached it while seeking the minimum number of characters. This could
1015        happen only if some of the characters were more than one byte long, because
1016        there is a check for at least the minimum number of bytes.
1018    21. Refactored the implementation of \p and \P so as to be more general, to
1019        allow for more different types of property in future. This has changed the
1020        compiled form incompatibly. Anybody with saved compiled patterns that use
1021        \p or \P will have to recompile them.
1023    22. Added "Any" and "L&" to the supported property types.
1025    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1026        but give a compile time error if the value is greater than 0xff.
1028    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1029        accidentally not being installed or uninstalled.
1031    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1032        made were to insert the current release number. This seemed silly, because
1033        it made things harder for people building PCRE on systems that don't run
1034        "configure". I have turned pcre.h into a distributed file, no longer built
1035        by "configure", with the version identification directly included. There is
1036        no longer a pcre.h.in file.
1038        However, this change necessitated a change to the pcre-config script as
1039        well. It is built from pcre-config.in, and one of the substitutions was the
1040        release number. I have updated configure.ac so that ./configure now finds
1041        the release number by grepping pcre.h.
1043    26. Added the ability to run the tests under valgrind.
1046  Version 6.4 05-Sep-05  Version 6.4 05-Sep-05
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