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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 05-Jul-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" for long printing in the pcrecpp
33        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.
52    Version 7.2 19-Jun-07
53    ---------------------
55     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
56        which is apparently normally available under Windows.
58     2. Re-jig the pcregrep tests with different newline settings in an attempt
59        to make them independent of the local environment's newline setting.
61     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
63     4. Some of the "internals" tests were previously cut out when the link size
64        was not 2, because the output contained actual offsets. The recent new
65        "Z" feature of pcretest means that these can be cut out, making the tests
66        usable with all link sizes.
68     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
69        stack recursion. This gives a massive performance boost under BSD, but just
70        a small improvement under Linux. However, it saves one field in the frame
71        in all cases.
73     6. Added more features from the forthcoming Perl 5.10:
75        (a) (?-n) (where n is a string of digits) is a relative subroutine or
76            recursion call. It refers to the nth most recently opened parentheses.
78        (b) (?+n) is also a relative subroutine call; it refers to the nth next
79            to be opened parentheses.
81        (c) Conditions that refer to capturing parentheses can be specified
82            relatively, for example, (?(-2)... or (?(+3)...
84        (d) \K resets the start of the current match so that everything before
85            is not part of it.
87        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
89        (f) \g{name} is another synonym - part of Perl 5.10's unification of
90            reference syntax.
92        (g) (?| introduces a group in which the numbering of parentheses in each
93            alternative starts with the same number.
95        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
97     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
100     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
101        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
102        for detecting groups that can match an empty string.
104     9. A pattern with a very large number of alternatives (more than several
105        hundred) was running out of internal workspace during the pre-compile
106        phase, where pcre_compile() figures out how much memory will be needed. A
107        bit of new cunning has reduced the workspace needed for groups with
108        alternatives. The 1000-alternative test pattern now uses 12 bytes of
109        workspace instead of running out of the 4096 that are available.
111    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
113    11. Applied patch from Google to remove an optimization that didn't quite work.
114        The report of the bug said:
116          pcrecpp::RE("a*").FullMatch("aaa") matches, while
117          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
118          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
120    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
121        it matched the wrong number of bytes.
124    Version 7.1 24-Apr-07
125    ---------------------
127     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
128        that is more "standard", making use of automake and other Autotools. There
129        is some re-arrangement of the files and adjustment of comments consequent
130        on this.
132     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
133        for recursive directory scanning broke on some systems because the files
134        are not scanned in any specific order and on different systems the order
135        was different. A call to "sort" has been inserted into RunGrepTest for the
136        approprate test as a short-term fix. In the longer term there may be an
137        alternative.
139     3. I had an email from Eric Raymond about problems translating some of PCRE's
140        man pages to HTML (despite the fact that I distribute HTML pages, some
141        people do their own conversions for various reasons). The problems
142        concerned the use of low-level troff macros .br and .in. I have therefore
143        removed all such uses from the man pages (some were redundant, some could
144        be replaced by .nf/.fi pairs). The 132html script that I use to generate
145        HTML has been updated to handle .nf/.fi and to complain if it encounters
146        .br or .in.
148     4. Updated comments in configure.ac that get placed in config.h.in and also
149        arranged for config.h to be included in the distribution, with the name
150        config.h.generic, for the benefit of those who have to compile without
151        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
153     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
154        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
155        makevp.bat for the current PCRE, using the additional files
156        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
158     6. A Windows user reported a minor discrepancy with test 2, which turned out
159        to be caused by a trailing space on an input line that had got lost in his
160        copy. The trailing space was an accident, so I've just removed it.
162     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
163        that is needed.
165     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
166        as "const" (a) because they are and (b) because it helps the PHP
167        maintainers who have recently made a script to detect big data structures
168        in the php code that should be moved to the .rodata section. I remembered
169        to update Builducptable as well, so it won't revert if ucptable.h is ever
170        re-created.
172     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
173        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
174        order to be able to cut out the UTF-8 tables in the latter when UTF-8
175        support is not required. This saves 1.5-2K of code, which is important in
176        some applications.
178        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
179        so as not to refer to the tables, even though these functions will never be
180        called when UTF-8 support is disabled. Otherwise there are problems with a
181        shared library.
183    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
185        (a) It was defining its arguments as char * instead of void *.
187        (b) It was assuming that all moves were upwards in memory; this was true
188            a long time ago when I wrote it, but is no longer the case.
190        The emulated memove() is provided for those environments that have neither
191        memmove() nor bcopy(). I didn't think anyone used it these days, but that
192        is clearly not the case, as these two bugs were recently reported.
194    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
195        and Detrail to create the HTML documentation, the .txt form of the man
196        pages, and it removes trailing spaces from listed files. It also creates
197        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
198        case, it wraps all the #defines with #ifndefs. This script should be run
199        before "make dist".
201    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
202        with Unicode property support.
204        (a) For a maximizing quantifier, if the two different cases of the
205            character were of different lengths in their UTF-8 codings (there are
206            some cases like this - I found 11), and the matching function had to
207            back up over a mixture of the two cases, it incorrectly assumed they
208            were both the same length.
210        (b) When PCRE was configured to use the heap rather than the stack for
211            recursion during matching, it was not correctly preserving the data for
212            the other case of a UTF-8 character when checking ahead for a match
213            while processing a minimizing repeat. If the check also involved
214            matching a wide character, but failed, corruption could cause an
215            erroneous result when trying to check for a repeat of the original
216            character.
218    13. Some tidying changes to the testing mechanism:
220        (a) The RunTest script now detects the internal link size and whether there
221            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
222            values substituted by "configure". (The RunGrepTest script already did
223            this for UTF-8.) The configure.ac script no longer substitutes the
224            relevant variables.
226        (b) The debugging options /B and /D in pcretest show the compiled bytecode
227            with length and offset values. This means that the output is different
228            for different internal link sizes. Test 2 is skipped for link sizes
229            other than 2 because of this, bypassing the problem. Unfortunately,
230            there was also a test in test 3 (the locale tests) that used /B and
231            failed for link sizes other than 2. Rather than cut the whole test out,
232            I have added a new /Z option to pcretest that replaces the length and
233            offset values with spaces. This is now used to make test 3 independent
234            of link size. (Test 2 will be tidied up later.)
236    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
237        segmentation fault instead of returning the appropriate error message.
239    15. In multiline mode when the newline sequence was set to "any", the pattern
240        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
241        This doesn't seem right; it now treats the CRLF combination as the line
242        ending, and so does not match in that case. It's only a pattern such as ^$
243        that would hit this one: something like ^ABC$ would have failed after \r
244        and then tried again after \r\n.
246    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
247        in an attempt to make files that differ only in their line terminators
248        compare equal. This works on Linux.
250    17. Under certain error circumstances pcregrep might try to free random memory
251        as it exited. This is now fixed, thanks to valgrind.
253    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
254        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
255        was because its rules for how to advance for /g after matching an empty
256        string at the end of a line did not allow for this case. They now check for
257        it specially.
259    20. pcretest is supposed to handle patterns and data of any length, by
260        extending its buffers when necessary. It was getting this wrong when the
261        buffer for a data line had to be extended.
263    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
264        CRLF as a newline sequence.
266    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
267        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
268        I have nevertheless tidied it up.
270    23. Added some casts to kill warnings from HP-UX ia64 compiler.
272    24. Added a man page for pcre-config.
275    Version 7.0 19-Dec-06
276    ---------------------
278     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
279        moving to gcc 4.1.1.
281     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
282        sys/time.h, which is documented as needed for this function. It doesn't
283        seem to matter on Linux, but it showed up on some releases of OS X.
285     3. It seems that there are systems where bytes whose values are greater than
286        127 match isprint() in the "C" locale. The "C" locale should be the
287        default when a C program starts up. In most systems, only ASCII printing
288        characters match isprint(). This difference caused the output from pcretest
289        to vary, making some of the tests fail. I have changed pcretest so that:
291        (a) When it is outputting text in the compiled version of a pattern, bytes
292            other than 32-126 are always shown as hex escapes.
294        (b) When it is outputting text that is a matched part of a subject string,
295            it does the same, unless a different locale has been set for the match
296            (using the /L modifier). In this case, it uses isprint() to decide.
298     4. Fixed a major bug that caused incorrect computation of the amount of memory
299        required for a compiled pattern when options that changed within the
300        pattern affected the logic of the preliminary scan that determines the
301        length. The relevant options are -x, and -i in UTF-8 mode. The result was
302        that the computed length was too small. The symptoms of this bug were
303        either the PCRE error "internal error: code overflow" from pcre_compile(),
304        or a glibc crash with a message such as "pcretest: free(): invalid next
305        size (fast)". Examples of patterns that provoked this bug (shown in
306        pcretest format) are:
308          /(?-x: )/x
309          /(?x)(?-x: \s*#\s*)/
310          /((?i)[\x{c0}])/8
311          /(?i:[\x{c0}])/8
313        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
314        is now done differently.
316     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
317        wrapper classes; (b) implement a new function in the C++ scanner that is
318        more efficient than the old way of doing things because it avoids levels of
319        recursion in the regex matching; (c) add a paragraph to the documentation
320        for the FullMatch() function.
322     6. The escape sequence \n was being treated as whatever was defined as
323        "newline". Not only was this contrary to the documentation, which states
324        that \n is character 10 (hex 0A), but it also went horribly wrong when
325        "newline" was defined as CRLF. This has been fixed.
327     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
328        was being set to -1 for the "end of line" case (supposedly a value that no
329        character can have). Though this value is never used (the check for end of
330        line is "zero bytes in current character"), it caused compiler complaints.
331        I've changed it to 0xffffffff.
333     8. In pcre_version.c, the version string was being built by a sequence of
334        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
335        string (as it is for production releases) called a macro with an empty
336        argument. The C standard says the result of this is undefined. The gcc
337        compiler treats it as an empty string (which was what was wanted) but it is
338        reported that Visual C gives an error. The source has been hacked around to
339        avoid this problem.
341     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
342        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
343        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
344        of them did).
346    10. Originally, pcretest opened its input and output without "b"; then I was
347        told that "b" was needed in some environments, so it was added for release
348        5.0 to both the input and output. (It makes no difference on Unix-like
349        systems.) Later I was told that it is wrong for the input on Windows. I've
350        now abstracted the modes into two macros, to make it easier to fiddle with
351        them, and removed "b" from the input mode under Windows.
353    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
355    12. Added -help and --help to pcretest as an official way of being reminded
356        of the options.
358    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
359        and pcrecpp.cc because they annoy compilers at high warning levels.
361    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
363    15. Fixed an occurrence of == in configure.ac that should have been = (shell
364        scripts are not C programs :-) and which was not noticed because it works
365        on Linux.
367    16. pcretest is supposed to handle any length of pattern and data line (as one
368        line or as a continued sequence of lines) by extending its input buffer if
369        necessary. This feature was broken for very long pattern lines, leading to
370        a string of junk being passed to pcre_compile() if the pattern was longer
371        than about 50K.
373    17. I have done a major re-factoring of the way pcre_compile() computes the
374        amount of memory needed for a compiled pattern. Previously, there was code
375        that made a preliminary scan of the pattern in order to do this. That was
376        OK when PCRE was new, but as the facilities have expanded, it has become
377        harder and harder to keep it in step with the real compile phase, and there
378        have been a number of bugs (see for example, 4 above). I have now found a
379        cunning way of running the real compile function in a "fake" mode that
380        enables it to compute how much memory it would need, while actually only
381        ever using a few hundred bytes of working memory and without too many
382        tests of the mode. This should make future maintenance and development
383        easier. A side effect of this work is that the limit of 200 on the nesting
384        depth of parentheses has been removed (though this was never a serious
385        limitation, I suspect). However, there is a downside: pcre_compile() now
386        runs more slowly than before (30% or more, depending on the pattern). I
387        hope this isn't a big issue. There is no effect on runtime performance.
389    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
390        newline (only possible for the last line of a file) and it was a
391        pattern that set a locale (followed by /Lsomething), pcretest crashed.
393    19. Added additional timing features to pcretest. (1) The -tm option now times
394        matching only, not compiling. (2) Both -t and -tm can be followed, as a
395        separate command line item, by a number that specifies the number of
396        repeats to use when timing. The default is 50000; this gives better
397        precision, but takes uncomfortably long for very large patterns.
399    20. Extended pcre_study() to be more clever in cases where a branch of a
400        subpattern has no definite first character. For example, (a*|b*)[cd] would
401        previously give no result from pcre_study(). Now it recognizes that the
402        first character must be a, b, c, or d.
404    21. There was an incorrect error "recursive call could loop indefinitely" if
405        a subpattern (or the entire pattern) that was being tested for matching an
406        empty string contained only one non-empty item after a nested subpattern.
407        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
408        incorrectly, because the \d was being skipped in the check.
410    22. The pcretest program now has a new pattern option /B and a command line
411        option -b, which is equivalent to adding /B to every pattern. This causes
412        it to show the compiled bytecode, without the additional information that
413        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
414        is the same as /B/I).
416    23. A new optimization is now able automatically to treat some sequences such
417        as a*b as a*+b. More specifically, if something simple (such as a character
418        or a simple class like \d) has an unlimited quantifier, and is followed by
419        something that cannot possibly match the quantified thing, the quantifier
420        is automatically "possessified".
422    24. A recursive reference to a subpattern whose number was greater than 39
423        went wrong under certain circumstances in UTF-8 mode. This bug could also
424        have affected the operation of pcre_study().
426    25. Realized that a little bit of performance could be had by replacing
427        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
429    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
431    27. Possessive quantifiers such as a++ were previously implemented by turning
432        them into atomic groups such as ($>a+). Now they have their own opcodes,
433        which improves performance. This includes the automatically created ones
434        from 23 above.
436    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
437        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
438        the first matched character to be a colon. This applied both to named and
439        numbered groups.
441    29. The ucpinternal.h header file was missing its idempotency #ifdef.
443    30. I was sent a "project" file called libpcre.a.dev which I understand makes
444        building PCRE on Windows easier, so I have included it in the distribution.
446    31. There is now a check in pcretest against a ridiculously large number being
447        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
448        loop, the loop is abandoned.
450    32. Forward references to subpatterns in conditions such as (?(2)...) where
451        subpattern 2 is defined later cause pcre_compile() to search forwards in
452        the pattern for the relevant set of parentheses. This search went wrong
453        when there were unescaped parentheses in a character class, parentheses
454        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
456    33. "Subroutine" calls and backreferences were previously restricted to
457        referencing subpatterns earlier in the regex. This restriction has now
458        been removed.
460    34. Added a number of extra features that are going to be in Perl 5.10. On the
461        whole, these are just syntactic alternatives for features that PCRE had
462        previously implemented using the Python syntax or my own invention. The
463        other formats are all retained for compatibility.
465        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
466            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
467            also .NET compatible.
469        (b) A recursion or subroutine call to a named group can now be defined as
470            (?&name) as well as (?P>name).
472        (c) A backreference to a named group can now be defined as \k<name> or
473            \k'name' as well as (?P=name). The new forms, as well as being in Perl
474            5.10, are also .NET compatible.
476        (d) A conditional reference to a named group can now use the syntax
477            (?(<name>) or (?('name') as well as (?(name).
479        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
480            groups (named and numbered) that are never evaluated inline, but can be
481            called as "subroutines" from elsewhere. In effect, the DEFINE condition
482            is always false. There may be only one alternative in such a group.
484        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
485            as the simple (?(R). The condition is true only if the most recent
486            recursion is that of the given number or name. It does not search out
487            through the entire recursion stack.
489        (g) The escape \gN or \g{N} has been added, where N is a positive or
490            negative number, specifying an absolute or relative reference.
492    35. Tidied to get rid of some further signed/unsigned compiler warnings and
493        some "unreachable code" warnings.
495    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
496        things, this adds five new scripts.
498    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
499        There were also incompatibilities regarding the handling of \Q..\E inside
500        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
501        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
503    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
504        matches an empty string, and forcibly breaks the loop. There were bugs in
505        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
506        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
507        separate and independent bugs (that affected different cases) have been
508        fixed.
510    39. Refactored the code to abolish the use of different opcodes for small
511        capturing bracket numbers. This is a tidy that I avoided doing when I
512        removed the limit on the number of capturing brackets for 3.5 back in 2001.
513        The new approach is not only tidier, it makes it possible to reduce the
514        memory needed to fix the previous bug (38).
516    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
517        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
518        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
519        mode.
521    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
522        report.
524    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
525        copy construction and assignment in the C++ wrapper.
527    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
528        couple of bugs that could have given wrong results in the "--newline=crlf"
529        case.
531    44. Added a number of casts and did some reorganization of signed/unsigned int
532        variables following suggestions from Dair Grant. Also renamed the variable
533        "this" as "item" because it is a C++ keyword.
535    45. Arranged for dftables to add
537          #include "pcre_internal.h"
539        to pcre_chartables.c because without it, gcc 4.x may remove the array
540        definition from the final binary if PCRE is built into a static library and
541        dead code stripping is activated.
543    46. For an unanchored pattern, if a match attempt fails at the start of a
544        newline sequence, and the newline setting is CRLF or ANY, and the next two
545        characters are CRLF, advance by two characters instead of one.
548    Version 6.7 04-Jul-06
549    ---------------------
551     1. In order to handle tests when input lines are enormously long, pcretest has
552        been re-factored so that it automatically extends its buffers when
553        necessary. The code is crude, but this _is_ just a test program. The
554        default size has been increased from 32K to 50K.
556     2. The code in pcre_study() was using the value of the re argument before
557        testing it for NULL. (Of course, in any sensible call of the function, it
558        won't be NULL.)
560     3. The memmove() emulation function in pcre_internal.h, which is used on
561        systems that lack both memmove() and bcopy() - that is, hardly ever -
562        was missing a "static" storage class specifier.
564     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
565        containing an extended class (one that cannot be represented by a bitmap
566        because it contains high-valued characters or Unicode property items, e.g.
567        [\pZ]). Almost always one would set UTF-8 mode when processing such a
568        pattern, but PCRE should not loop if you do not (it no longer does).
569        [Detail: two cases were found: (a) a repeated subpattern containing an
570        extended class; (b) a recursive reference to a subpattern that followed a
571        previous extended class. It wasn't skipping over the extended class
572        correctly when UTF-8 mode was not set.]
574     5. A negated single-character class was not being recognized as fixed-length
575        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
576        compile error "lookbehind assertion is not fixed length".
578     6. The RunPerlTest auxiliary script was showing an unexpected difference
579        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
580        write a Perl script that can interpret lines of an input file either as
581        byte characters or as UTF-8, which is what "perltest" was being required to
582        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
583        can't do is switch easily at run time between having the "use utf8;" pragma
584        or not. In the end, I fudged it by using the RunPerlTest script to insert
585        "use utf8;" explicitly for the UTF-8 tests.
587     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
588        the end of the subject string, contrary to the documentation and to what
589        Perl does. This was true of both matching functions. Now it matches only at
590        the start of the subject and immediately after *internal* newlines.
592     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
593        a pointer to an int instead of a pointer to an unsigned long int. This
594        caused problems on 64-bit systems.
596     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
597        instance of the 'standard' template library not being so standard".
599    10. There was no check on the number of named subpatterns nor the maximum
600        length of a subpattern name. The product of these values is used to compute
601        the size of the memory block for a compiled pattern. By supplying a very
602        long subpattern name and a large number of named subpatterns, the size
603        computation could be caused to overflow. This is now prevented by limiting
604        the length of names to 32 characters, and the number of named subpatterns
605        to 10,000.
607    11. Subpatterns that are repeated with specific counts have to be replicated in
608        the compiled pattern. The size of memory for this was computed from the
609        length of the subpattern and the repeat count. The latter is limited to
610        65535, but there was no limit on the former, meaning that integer overflow
611        could in principle occur. The compiled length of a repeated subpattern is
612        now limited to 30,000 bytes in order to prevent this.
614    12. Added the optional facility to have named substrings with the same name.
616    13. Added the ability to use a named substring as a condition, using the
617        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
618        are numbers (not recommended). Forward references are permitted.
620    14. Added forward references in named backreferences (if you see what I mean).
622    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
623        pattern could run off the end of the subject. For example, the pattern
624        "(?s)(.{1,5})"8 did this with the subject "ab".
626    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
627        PCRE_CASELESS was set when matching characters that were quantified with ?
628        or *.
630    17. A character class other than a single negated character that had a minimum
631        but no maximum quantifier - for example [ab]{6,} - was not handled
632        correctly by pce_dfa_exec(). It would match only one character.
634    18. A valid (though odd) pattern that looked like a POSIX character
635        class but used an invalid character after [ (for example [[,abc,]]) caused
636        pcre_compile() to give the error "Failed: internal error: code overflow" or
637        in some cases to crash with a glibc free() error. This could even happen if
638        the pattern terminated after [[ but there just happened to be a sequence of
639        letters, a binary zero, and a closing ] in the memory that followed.
641    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
642        over the years. Originally (before any Unicode support), just the bottom 8
643        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
644        output from "man perlunicode" includes this:
646          The regular expression compiler produces polymorphic opcodes.  That
647          is, the pattern adapts to the data and automatically switches to
648          the Unicode character scheme when presented with Unicode data--or
649          instead uses a traditional byte scheme when presented with byte
650          data.
652        Sadly, a wide octal escape does not cause a switch, and in a string with
653        no other multibyte characters, these octal escapes are treated as before.
654        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
655        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
656        Unicode string.
658        I have not perpetrated such confusion in PCRE. Up till now, it took just
659        the bottom 8 bits, as in old Perl. I have now made octal escapes with
660        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
661        translate to the appropriate multibyte character.
663    29. Applied some refactoring to reduce the number of warnings from Microsoft
664        and Borland compilers. This has included removing the fudge introduced
665        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
666        a warning about an unused variable.
668    21. PCRE has not included VT (character 0x0b) in the set of whitespace
669        characters since release 4.0, because Perl (from release 5.004) does not.
670        [Or at least, is documented not to: some releases seem to be in conflict
671        with the documentation.] However, when a pattern was studied with
672        pcre_study() and all its branches started with \s, PCRE still included VT
673        as a possible starting character. Of course, this did no harm; it just
674        caused an unnecessary match attempt.
676    22. Removed a now-redundant internal flag bit that recorded the fact that case
677        dependency changed within the pattern. This was once needed for "required
678        byte" processing, but is no longer used. This recovers a now-scarce options
679        bit. Also moved the least significant internal flag bit to the most-
680        significant bit of the word, which was not previously used (hangover from
681        the days when it was an int rather than a uint) to free up another bit for
682        the future.
684    23. Added support for CRLF line endings as well as CR and LF. As well as the
685        default being selectable at build time, it can now be changed at runtime
686        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
687        specify that it is scanning data with non-default line endings.
689    24. Changed the definition of CXXLINK to make it agree with the definition of
690        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
692    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
693        recursions. This makes a big different to stack usage for some patterns.
695    26. If a subpattern containing a named recursion or subroutine reference such
696        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
697        the space required for the compiled pattern went wrong and gave too small a
698        value. Depending on the environment, this could lead to "Failed: internal
699        error: code overflow at offset 49" or "glibc detected double free or
700        corruption" errors.
702    27. Applied patches from Google (a) to support the new newline modes and (b) to
703        advance over multibyte UTF-8 characters in GlobalReplace.
705    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
706        difference for some implementation of PCRE in some Windows version.
708    29. Added some extra testing facilities to pcretest:
710        \q<number>   in a data line sets the "match limit" value
711        \Q<number>   in a data line sets the "match recursion limt" value
712        -S <number>  sets the stack size, where <number> is in megabytes
714        The -S option isn't available for Windows.
717    Version 6.6 06-Feb-06
718    ---------------------
720     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
721        in pcreposix.h. I have copied the definition from pcre.h.
723     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
724        because pcre.h is no longer a built file.
726     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
727        not normally included in the compiled code.
730    Version 6.5 01-Feb-06
731    ---------------------
733     1. When using the partial match feature with pcre_dfa_exec(), it was not
734        anchoring the second and subsequent partial matches at the new starting
735        point. This could lead to incorrect results. For example, with the pattern
736        /1234/, partially matching against "123" and then "a4" gave a match.
738     2. Changes to pcregrep:
740        (a) All non-match returns from pcre_exec() were being treated as failures
741            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
742            error message is output. Some extra information is given for the
743            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
744            probably the only errors that are likely to be caused by users (by
745            specifying a regex that has nested indefinite repeats, for instance).
746            If there are more than 20 of these errors, pcregrep is abandoned.
748        (b) A binary zero was treated as data while matching, but terminated the
749            output line if it was written out. This has been fixed: binary zeroes
750            are now no different to any other data bytes.
752        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
753            used to set a locale for matching. The --locale=xxxx long option has
754            been added (no short equivalent) to specify a locale explicitly on the
755            pcregrep command, overriding the environment variables.
757        (d) When -B was used with -n, some line numbers in the output were one less
758            than they should have been.
760        (e) Added the -o (--only-matching) option.
762        (f) If -A or -C was used with -c (count only), some lines of context were
763            accidentally printed for the final match.
765        (g) Added the -H (--with-filename) option.
767        (h) The combination of options -rh failed to suppress file names for files
768            that were found from directory arguments.
770        (i) Added the -D (--devices) and -d (--directories) options.
772        (j) Added the -F (--fixed-strings) option.
774        (k) Allow "-" to be used as a file name for -f as well as for a data file.
776        (l) Added the --colo(u)r option.
778        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
779            is not present by default.
781     3. A nasty bug was discovered in the handling of recursive patterns, that is,
782        items such as (?R) or (?1), when the recursion could match a number of
783        alternatives. If it matched one of the alternatives, but subsequently,
784        outside the recursion, there was a failure, the code tried to back up into
785        the recursion. However, because of the way PCRE is implemented, this is not
786        possible, and the result was an incorrect result from the match.
788        In order to prevent this happening, the specification of recursion has
789        been changed so that all such subpatterns are automatically treated as
790        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
792     4. I had overlooked the fact that, in some locales, there are characters for
793        which isalpha() is true but neither isupper() nor islower() are true. In
794        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
795        and ordfeminine) are like this. This affected the treatment of \w and \W
796        when they appeared in character classes, but not when they appeared outside
797        a character class. The bit map for "word" characters is now created
798        separately from the results of isalnum() instead of just taking it from the
799        upper, lower, and digit maps. (Plus the underscore character, of course.)
801     5. The above bug also affected the handling of POSIX character classes such as
802        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
803        permanent tables. Instead, the bit maps for such a class were previously
804        created as the appropriate unions of the upper, lower, and digit bitmaps.
805        Now they are created by subtraction from the [[:word:]] class, which has
806        its own bitmap.
808     6. The [[:blank:]] character class matches horizontal, but not vertical space.
809        It is created by subtracting the vertical space characters (\x09, \x0a,
810        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
811        subtraction was done in the overall bitmap for a character class, meaning
812        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
813        be recognized. This bug has been fixed.
815     7. Patches from the folks at Google:
817          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
818          real life, but is still worth protecting against".
820          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
821          regular expressions".
823          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
824          have it.
826          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
827          "configure" and the latter not, in order to fix a problem somebody had
828          with compiling the Arg class on HP-UX.
830          (e) Improve the error-handling of the C++ wrapper a little bit.
832          (f) New tests for checking recursion limiting.
834     8. The pcre_memmove() function, which is used only if the environment does not
835        have a standard memmove() function (and is therefore rarely compiled),
836        contained two bugs: (a) use of int instead of size_t, and (b) it was not
837        returning a result (though PCRE never actually uses the result).
839     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
840        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
841        returned instead of calling malloc() with an overflowing number that would
842        most likely cause subsequent chaos.
844    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
846    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
847        with this option is matched, the nmatch and pmatch options of regexec() are
848        ignored.
850    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
851        provided in case anyone wants to the the POSIX interface with UTF-8
852        strings.
854    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
855        C++ linking (needed for some HP-UX environments).
857    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
858        (unused parameter) and in the pcre_printint() function (omitted "default"
859        switch label when the default is to do nothing).
861    15. Added some code to make it possible, when PCRE is compiled as a C++
862        library, to replace subject pointers for pcre_exec() with a smart pointer
863        class, thus making it possible to process discontinuous strings.
865    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
866        much the same function. They were added by different people who were trying
867        to make PCRE easy to compile on non-Unix systems. It has been suggested
868        that PCRE_EXPORT be abolished now that there is more automatic apparatus
869        for compiling on Windows systems. I have therefore replaced it with
870        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
871        defaults to "extern" for C or "extern C" for C++, which works fine on
872        Unix-like systems. It is now possible to override the value of PCRE_DATA_
873        SCOPE with something explicit in config.h. In addition:
875        (a) pcreposix.h still had just "extern" instead of either of these macros;
876            I have replaced it with PCRE_DATA_SCOPE.
878        (b) Functions such as _pcre_xclass(), which are internal to the library,
879            but external in the C sense, all had PCRE_EXPORT in their definitions.
880            This is apparently wrong for the Windows case, so I have removed it.
881            (It makes no difference on Unix-like systems.)
883    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
884        of recursive calls to match(). This is different to MATCH_LIMIT because
885        that limits the total number of calls to match(), not all of which increase
886        the depth of recursion. Limiting the recursion depth limits the amount of
887        stack (or heap if NO_RECURSE is set) that is used. The default can be set
888        when PCRE is compiled, and changed at run time. A patch from Google adds
889        this functionality to the C++ interface.
891    18. Changes to the handling of Unicode character properties:
893        (a) Updated the table to Unicode 4.1.0.
895        (b) Recognize characters that are not in the table as "Cn" (undefined).
897        (c) I revised the way the table is implemented to a much improved format
898            which includes recognition of ranges. It now supports the ranges that
899            are defined in UnicodeData.txt, and it also amalgamates other
900            characters into ranges. This has reduced the number of entries in the
901            table from around 16,000 to around 3,000, thus reducing its size
902            considerably. I realized I did not need to use a tree structure after
903            all - a binary chop search is just as efficient. Having reduced the
904            number of entries, I extended their size from 6 bytes to 8 bytes to
905            allow for more data.
907        (d) Added support for Unicode script names via properties such as \p{Han}.
909    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
910        matching that character.
912    20. When matching a repeated Unicode property with a minimum greater than zero,
913        (for example \pL{2,}), PCRE could look past the end of the subject if it
914        reached it while seeking the minimum number of characters. This could
915        happen only if some of the characters were more than one byte long, because
916        there is a check for at least the minimum number of bytes.
918    21. Refactored the implementation of \p and \P so as to be more general, to
919        allow for more different types of property in future. This has changed the
920        compiled form incompatibly. Anybody with saved compiled patterns that use
921        \p or \P will have to recompile them.
923    22. Added "Any" and "L&" to the supported property types.
925    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
926        but give a compile time error if the value is greater than 0xff.
928    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
929        accidentally not being installed or uninstalled.
931    25. The pcre.h file was built from pcre.h.in, but the only changes that were
932        made were to insert the current release number. This seemed silly, because
933        it made things harder for people building PCRE on systems that don't run
934        "configure". I have turned pcre.h into a distributed file, no longer built
935        by "configure", with the version identification directly included. There is
936        no longer a pcre.h.in file.
938        However, this change necessitated a change to the pcre-config script as
939        well. It is built from pcre-config.in, and one of the substitutions was the
940        release number. I have updated configure.ac so that ./configure now finds
941        the release number by grepping pcre.h.
943    26. Added the ability to run the tests under valgrind.
946    Version 6.4 05-Sep-05
947    ---------------------
949     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
950        "--" to be printed when multiple files were scanned, even when none of the
951        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
952        consider it to be a bug, and have restored the previous behaviour.
954     2. A couple of code tidies to get rid of compiler warnings.
956     3. The pcretest program used to cheat by referring to symbols in the library
957        whose names begin with _pcre_. These are internal symbols that are not
958        really supposed to be visible externally, and in some environments it is
959        possible to suppress them. The cheating is now confined to including
960        certain files from the library's source, which is a bit cleaner.
962     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
963        file's purpose clearer.
965     5. Reorganized pcre_ucp_findchar().
968  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
969  ---------------------  ---------------------

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