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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.
39    Version 7.2 19-Jun-07
40    ---------------------
42     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
43        which is apparently normally available under Windows.
45     2. Re-jig the pcregrep tests with different newline settings in an attempt
46        to make them independent of the local environment's newline setting.
48     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
50     4. Some of the "internals" tests were previously cut out when the link size
51        was not 2, because the output contained actual offsets. The recent new
52        "Z" feature of pcretest means that these can be cut out, making the tests
53        usable with all link sizes.
55     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
56        stack recursion. This gives a massive performance boost under BSD, but just
57        a small improvement under Linux. However, it saves one field in the frame
58        in all cases.
60     6. Added more features from the forthcoming Perl 5.10:
62        (a) (?-n) (where n is a string of digits) is a relative subroutine or
63            recursion call. It refers to the nth most recently opened parentheses.
65        (b) (?+n) is also a relative subroutine call; it refers to the nth next
66            to be opened parentheses.
68        (c) Conditions that refer to capturing parentheses can be specified
69            relatively, for example, (?(-2)... or (?(+3)...
71        (d) \K resets the start of the current match so that everything before
72            is not part of it.
74        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
76        (f) \g{name} is another synonym - part of Perl 5.10's unification of
77            reference syntax.
79        (g) (?| introduces a group in which the numbering of parentheses in each
80            alternative starts with the same number.
82        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
84     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
87     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
88        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
89        for detecting groups that can match an empty string.
91     9. A pattern with a very large number of alternatives (more than several
92        hundred) was running out of internal workspace during the pre-compile
93        phase, where pcre_compile() figures out how much memory will be needed. A
94        bit of new cunning has reduced the workspace needed for groups with
95        alternatives. The 1000-alternative test pattern now uses 12 bytes of
96        workspace instead of running out of the 4096 that are available.
98    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
100    11. Applied patch from Google to remove an optimization that didn't quite work.
101        The report of the bug said:
103          pcrecpp::RE("a*").FullMatch("aaa") matches, while
104          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
105          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
107    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
108        it matched the wrong number of bytes.
111    Version 7.1 24-Apr-07
112    ---------------------
114     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
115        that is more "standard", making use of automake and other Autotools. There
116        is some re-arrangement of the files and adjustment of comments consequent
117        on this.
119     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
120        for recursive directory scanning broke on some systems because the files
121        are not scanned in any specific order and on different systems the order
122        was different. A call to "sort" has been inserted into RunGrepTest for the
123        approprate test as a short-term fix. In the longer term there may be an
124        alternative.
126     3. I had an email from Eric Raymond about problems translating some of PCRE's
127        man pages to HTML (despite the fact that I distribute HTML pages, some
128        people do their own conversions for various reasons). The problems
129        concerned the use of low-level troff macros .br and .in. I have therefore
130        removed all such uses from the man pages (some were redundant, some could
131        be replaced by .nf/.fi pairs). The 132html script that I use to generate
132        HTML has been updated to handle .nf/.fi and to complain if it encounters
133        .br or .in.
135     4. Updated comments in configure.ac that get placed in config.h.in and also
136        arranged for config.h to be included in the distribution, with the name
137        config.h.generic, for the benefit of those who have to compile without
138        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
140     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
141        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
142        makevp.bat for the current PCRE, using the additional files
143        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
145     6. A Windows user reported a minor discrepancy with test 2, which turned out
146        to be caused by a trailing space on an input line that had got lost in his
147        copy. The trailing space was an accident, so I've just removed it.
149     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
150        that is needed.
152     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
153        as "const" (a) because they are and (b) because it helps the PHP
154        maintainers who have recently made a script to detect big data structures
155        in the php code that should be moved to the .rodata section. I remembered
156        to update Builducptable as well, so it won't revert if ucptable.h is ever
157        re-created.
159     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
160        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
161        order to be able to cut out the UTF-8 tables in the latter when UTF-8
162        support is not required. This saves 1.5-2K of code, which is important in
163        some applications.
165        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
166        so as not to refer to the tables, even though these functions will never be
167        called when UTF-8 support is disabled. Otherwise there are problems with a
168        shared library.
170    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
172        (a) It was defining its arguments as char * instead of void *.
174        (b) It was assuming that all moves were upwards in memory; this was true
175            a long time ago when I wrote it, but is no longer the case.
177        The emulated memove() is provided for those environments that have neither
178        memmove() nor bcopy(). I didn't think anyone used it these days, but that
179        is clearly not the case, as these two bugs were recently reported.
181    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
182        and Detrail to create the HTML documentation, the .txt form of the man
183        pages, and it removes trailing spaces from listed files. It also creates
184        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
185        case, it wraps all the #defines with #ifndefs. This script should be run
186        before "make dist".
188    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
189        with Unicode property support.
191        (a) For a maximizing quantifier, if the two different cases of the
192            character were of different lengths in their UTF-8 codings (there are
193            some cases like this - I found 11), and the matching function had to
194            back up over a mixture of the two cases, it incorrectly assumed they
195            were both the same length.
197        (b) When PCRE was configured to use the heap rather than the stack for
198            recursion during matching, it was not correctly preserving the data for
199            the other case of a UTF-8 character when checking ahead for a match
200            while processing a minimizing repeat. If the check also involved
201            matching a wide character, but failed, corruption could cause an
202            erroneous result when trying to check for a repeat of the original
203            character.
205    13. Some tidying changes to the testing mechanism:
207        (a) The RunTest script now detects the internal link size and whether there
208            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
209            values substituted by "configure". (The RunGrepTest script already did
210            this for UTF-8.) The configure.ac script no longer substitutes the
211            relevant variables.
213        (b) The debugging options /B and /D in pcretest show the compiled bytecode
214            with length and offset values. This means that the output is different
215            for different internal link sizes. Test 2 is skipped for link sizes
216            other than 2 because of this, bypassing the problem. Unfortunately,
217            there was also a test in test 3 (the locale tests) that used /B and
218            failed for link sizes other than 2. Rather than cut the whole test out,
219            I have added a new /Z option to pcretest that replaces the length and
220            offset values with spaces. This is now used to make test 3 independent
221            of link size. (Test 2 will be tidied up later.)
223    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
224        segmentation fault instead of returning the appropriate error message.
226    15. In multiline mode when the newline sequence was set to "any", the pattern
227        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
228        This doesn't seem right; it now treats the CRLF combination as the line
229        ending, and so does not match in that case. It's only a pattern such as ^$
230        that would hit this one: something like ^ABC$ would have failed after \r
231        and then tried again after \r\n.
233    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
234        in an attempt to make files that differ only in their line terminators
235        compare equal. This works on Linux.
237    17. Under certain error circumstances pcregrep might try to free random memory
238        as it exited. This is now fixed, thanks to valgrind.
240    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
241        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
242        was because its rules for how to advance for /g after matching an empty
243        string at the end of a line did not allow for this case. They now check for
244        it specially.
246    20. pcretest is supposed to handle patterns and data of any length, by
247        extending its buffers when necessary. It was getting this wrong when the
248        buffer for a data line had to be extended.
250    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
251        CRLF as a newline sequence.
253    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
254        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
255        I have nevertheless tidied it up.
257    23. Added some casts to kill warnings from HP-UX ia64 compiler.
259    24. Added a man page for pcre-config.
262    Version 7.0 19-Dec-06
263    ---------------------
265     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
266        moving to gcc 4.1.1.
268     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
269        sys/time.h, which is documented as needed for this function. It doesn't
270        seem to matter on Linux, but it showed up on some releases of OS X.
272     3. It seems that there are systems where bytes whose values are greater than
273        127 match isprint() in the "C" locale. The "C" locale should be the
274        default when a C program starts up. In most systems, only ASCII printing
275        characters match isprint(). This difference caused the output from pcretest
276        to vary, making some of the tests fail. I have changed pcretest so that:
278        (a) When it is outputting text in the compiled version of a pattern, bytes
279            other than 32-126 are always shown as hex escapes.
281        (b) When it is outputting text that is a matched part of a subject string,
282            it does the same, unless a different locale has been set for the match
283            (using the /L modifier). In this case, it uses isprint() to decide.
285     4. Fixed a major bug that caused incorrect computation of the amount of memory
286        required for a compiled pattern when options that changed within the
287        pattern affected the logic of the preliminary scan that determines the
288        length. The relevant options are -x, and -i in UTF-8 mode. The result was
289        that the computed length was too small. The symptoms of this bug were
290        either the PCRE error "internal error: code overflow" from pcre_compile(),
291        or a glibc crash with a message such as "pcretest: free(): invalid next
292        size (fast)". Examples of patterns that provoked this bug (shown in
293        pcretest format) are:
295          /(?-x: )/x
296          /(?x)(?-x: \s*#\s*)/
297          /((?i)[\x{c0}])/8
298          /(?i:[\x{c0}])/8
300        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
301        is now done differently.
303     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
304        wrapper classes; (b) implement a new function in the C++ scanner that is
305        more efficient than the old way of doing things because it avoids levels of
306        recursion in the regex matching; (c) add a paragraph to the documentation
307        for the FullMatch() function.
309     6. The escape sequence \n was being treated as whatever was defined as
310        "newline". Not only was this contrary to the documentation, which states
311        that \n is character 10 (hex 0A), but it also went horribly wrong when
312        "newline" was defined as CRLF. This has been fixed.
314     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
315        was being set to -1 for the "end of line" case (supposedly a value that no
316        character can have). Though this value is never used (the check for end of
317        line is "zero bytes in current character"), it caused compiler complaints.
318        I've changed it to 0xffffffff.
320     8. In pcre_version.c, the version string was being built by a sequence of
321        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
322        string (as it is for production releases) called a macro with an empty
323        argument. The C standard says the result of this is undefined. The gcc
324        compiler treats it as an empty string (which was what was wanted) but it is
325        reported that Visual C gives an error. The source has been hacked around to
326        avoid this problem.
328     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
329        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
330        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
331        of them did).
333    10. Originally, pcretest opened its input and output without "b"; then I was
334        told that "b" was needed in some environments, so it was added for release
335        5.0 to both the input and output. (It makes no difference on Unix-like
336        systems.) Later I was told that it is wrong for the input on Windows. I've
337        now abstracted the modes into two macros, to make it easier to fiddle with
338        them, and removed "b" from the input mode under Windows.
340    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
342    12. Added -help and --help to pcretest as an official way of being reminded
343        of the options.
345    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
346        and pcrecpp.cc because they annoy compilers at high warning levels.
348    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
350    15. Fixed an occurrence of == in configure.ac that should have been = (shell
351        scripts are not C programs :-) and which was not noticed because it works
352        on Linux.
354    16. pcretest is supposed to handle any length of pattern and data line (as one
355        line or as a continued sequence of lines) by extending its input buffer if
356        necessary. This feature was broken for very long pattern lines, leading to
357        a string of junk being passed to pcre_compile() if the pattern was longer
358        than about 50K.
360    17. I have done a major re-factoring of the way pcre_compile() computes the
361        amount of memory needed for a compiled pattern. Previously, there was code
362        that made a preliminary scan of the pattern in order to do this. That was
363        OK when PCRE was new, but as the facilities have expanded, it has become
364        harder and harder to keep it in step with the real compile phase, and there
365        have been a number of bugs (see for example, 4 above). I have now found a
366        cunning way of running the real compile function in a "fake" mode that
367        enables it to compute how much memory it would need, while actually only
368        ever using a few hundred bytes of working memory and without too many
369        tests of the mode. This should make future maintenance and development
370        easier. A side effect of this work is that the limit of 200 on the nesting
371        depth of parentheses has been removed (though this was never a serious
372        limitation, I suspect). However, there is a downside: pcre_compile() now
373        runs more slowly than before (30% or more, depending on the pattern). I
374        hope this isn't a big issue. There is no effect on runtime performance.
376    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
377        newline (only possible for the last line of a file) and it was a
378        pattern that set a locale (followed by /Lsomething), pcretest crashed.
380    19. Added additional timing features to pcretest. (1) The -tm option now times
381        matching only, not compiling. (2) Both -t and -tm can be followed, as a
382        separate command line item, by a number that specifies the number of
383        repeats to use when timing. The default is 50000; this gives better
384        precision, but takes uncomfortably long for very large patterns.
386    20. Extended pcre_study() to be more clever in cases where a branch of a
387        subpattern has no definite first character. For example, (a*|b*)[cd] would
388        previously give no result from pcre_study(). Now it recognizes that the
389        first character must be a, b, c, or d.
391    21. There was an incorrect error "recursive call could loop indefinitely" if
392        a subpattern (or the entire pattern) that was being tested for matching an
393        empty string contained only one non-empty item after a nested subpattern.
394        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
395        incorrectly, because the \d was being skipped in the check.
397    22. The pcretest program now has a new pattern option /B and a command line
398        option -b, which is equivalent to adding /B to every pattern. This causes
399        it to show the compiled bytecode, without the additional information that
400        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
401        is the same as /B/I).
403    23. A new optimization is now able automatically to treat some sequences such
404        as a*b as a*+b. More specifically, if something simple (such as a character
405        or a simple class like \d) has an unlimited quantifier, and is followed by
406        something that cannot possibly match the quantified thing, the quantifier
407        is automatically "possessified".
409    24. A recursive reference to a subpattern whose number was greater than 39
410        went wrong under certain circumstances in UTF-8 mode. This bug could also
411        have affected the operation of pcre_study().
413    25. Realized that a little bit of performance could be had by replacing
414        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
416    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
418    27. Possessive quantifiers such as a++ were previously implemented by turning
419        them into atomic groups such as ($>a+). Now they have their own opcodes,
420        which improves performance. This includes the automatically created ones
421        from 23 above.
423    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
424        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
425        the first matched character to be a colon. This applied both to named and
426        numbered groups.
428    29. The ucpinternal.h header file was missing its idempotency #ifdef.
430    30. I was sent a "project" file called libpcre.a.dev which I understand makes
431        building PCRE on Windows easier, so I have included it in the distribution.
433    31. There is now a check in pcretest against a ridiculously large number being
434        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
435        loop, the loop is abandoned.
437    32. Forward references to subpatterns in conditions such as (?(2)...) where
438        subpattern 2 is defined later cause pcre_compile() to search forwards in
439        the pattern for the relevant set of parentheses. This search went wrong
440        when there were unescaped parentheses in a character class, parentheses
441        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
443    33. "Subroutine" calls and backreferences were previously restricted to
444        referencing subpatterns earlier in the regex. This restriction has now
445        been removed.
447    34. Added a number of extra features that are going to be in Perl 5.10. On the
448        whole, these are just syntactic alternatives for features that PCRE had
449        previously implemented using the Python syntax or my own invention. The
450        other formats are all retained for compatibility.
452        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
453            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
454            also .NET compatible.
456        (b) A recursion or subroutine call to a named group can now be defined as
457            (?&name) as well as (?P>name).
459        (c) A backreference to a named group can now be defined as \k<name> or
460            \k'name' as well as (?P=name). The new forms, as well as being in Perl
461            5.10, are also .NET compatible.
463        (d) A conditional reference to a named group can now use the syntax
464            (?(<name>) or (?('name') as well as (?(name).
466        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
467            groups (named and numbered) that are never evaluated inline, but can be
468            called as "subroutines" from elsewhere. In effect, the DEFINE condition
469            is always false. There may be only one alternative in such a group.
471        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
472            as the simple (?(R). The condition is true only if the most recent
473            recursion is that of the given number or name. It does not search out
474            through the entire recursion stack.
476        (g) The escape \gN or \g{N} has been added, where N is a positive or
477            negative number, specifying an absolute or relative reference.
479    35. Tidied to get rid of some further signed/unsigned compiler warnings and
480        some "unreachable code" warnings.
482    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
483        things, this adds five new scripts.
485    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
486        There were also incompatibilities regarding the handling of \Q..\E inside
487        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
488        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
490    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
491        matches an empty string, and forcibly breaks the loop. There were bugs in
492        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
493        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
494        separate and independent bugs (that affected different cases) have been
495        fixed.
497    39. Refactored the code to abolish the use of different opcodes for small
498        capturing bracket numbers. This is a tidy that I avoided doing when I
499        removed the limit on the number of capturing brackets for 3.5 back in 2001.
500        The new approach is not only tidier, it makes it possible to reduce the
501        memory needed to fix the previous bug (38).
503    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
504        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
505        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
506        mode.
508    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
509        report.
511    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
512        copy construction and assignment in the C++ wrapper.
514    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
515        couple of bugs that could have given wrong results in the "--newline=crlf"
516        case.
518    44. Added a number of casts and did some reorganization of signed/unsigned int
519        variables following suggestions from Dair Grant. Also renamed the variable
520        "this" as "item" because it is a C++ keyword.
522    45. Arranged for dftables to add
524          #include "pcre_internal.h"
526        to pcre_chartables.c because without it, gcc 4.x may remove the array
527        definition from the final binary if PCRE is built into a static library and
528        dead code stripping is activated.
530    46. For an unanchored pattern, if a match attempt fails at the start of a
531        newline sequence, and the newline setting is CRLF or ANY, and the next two
532        characters are CRLF, advance by two characters instead of one.
535    Version 6.7 04-Jul-06
536    ---------------------
538     1. In order to handle tests when input lines are enormously long, pcretest has
539        been re-factored so that it automatically extends its buffers when
540        necessary. The code is crude, but this _is_ just a test program. The
541        default size has been increased from 32K to 50K.
543     2. The code in pcre_study() was using the value of the re argument before
544        testing it for NULL. (Of course, in any sensible call of the function, it
545        won't be NULL.)
547     3. The memmove() emulation function in pcre_internal.h, which is used on
548        systems that lack both memmove() and bcopy() - that is, hardly ever -
549        was missing a "static" storage class specifier.
551     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
552        containing an extended class (one that cannot be represented by a bitmap
553        because it contains high-valued characters or Unicode property items, e.g.
554        [\pZ]). Almost always one would set UTF-8 mode when processing such a
555        pattern, but PCRE should not loop if you do not (it no longer does).
556        [Detail: two cases were found: (a) a repeated subpattern containing an
557        extended class; (b) a recursive reference to a subpattern that followed a
558        previous extended class. It wasn't skipping over the extended class
559        correctly when UTF-8 mode was not set.]
561     5. A negated single-character class was not being recognized as fixed-length
562        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
563        compile error "lookbehind assertion is not fixed length".
565     6. The RunPerlTest auxiliary script was showing an unexpected difference
566        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
567        write a Perl script that can interpret lines of an input file either as
568        byte characters or as UTF-8, which is what "perltest" was being required to
569        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
570        can't do is switch easily at run time between having the "use utf8;" pragma
571        or not. In the end, I fudged it by using the RunPerlTest script to insert
572        "use utf8;" explicitly for the UTF-8 tests.
574     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
575        the end of the subject string, contrary to the documentation and to what
576        Perl does. This was true of both matching functions. Now it matches only at
577        the start of the subject and immediately after *internal* newlines.
579     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
580        a pointer to an int instead of a pointer to an unsigned long int. This
581        caused problems on 64-bit systems.
583     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
584        instance of the 'standard' template library not being so standard".
586    10. There was no check on the number of named subpatterns nor the maximum
587        length of a subpattern name. The product of these values is used to compute
588        the size of the memory block for a compiled pattern. By supplying a very
589        long subpattern name and a large number of named subpatterns, the size
590        computation could be caused to overflow. This is now prevented by limiting
591        the length of names to 32 characters, and the number of named subpatterns
592        to 10,000.
594    11. Subpatterns that are repeated with specific counts have to be replicated in
595        the compiled pattern. The size of memory for this was computed from the
596        length of the subpattern and the repeat count. The latter is limited to
597        65535, but there was no limit on the former, meaning that integer overflow
598        could in principle occur. The compiled length of a repeated subpattern is
599        now limited to 30,000 bytes in order to prevent this.
601    12. Added the optional facility to have named substrings with the same name.
603    13. Added the ability to use a named substring as a condition, using the
604        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
605        are numbers (not recommended). Forward references are permitted.
607    14. Added forward references in named backreferences (if you see what I mean).
609    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
610        pattern could run off the end of the subject. For example, the pattern
611        "(?s)(.{1,5})"8 did this with the subject "ab".
613    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
614        PCRE_CASELESS was set when matching characters that were quantified with ?
615        or *.
617    17. A character class other than a single negated character that had a minimum
618        but no maximum quantifier - for example [ab]{6,} - was not handled
619        correctly by pce_dfa_exec(). It would match only one character.
621    18. A valid (though odd) pattern that looked like a POSIX character
622        class but used an invalid character after [ (for example [[,abc,]]) caused
623        pcre_compile() to give the error "Failed: internal error: code overflow" or
624        in some cases to crash with a glibc free() error. This could even happen if
625        the pattern terminated after [[ but there just happened to be a sequence of
626        letters, a binary zero, and a closing ] in the memory that followed.
628    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
629        over the years. Originally (before any Unicode support), just the bottom 8
630        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
631        output from "man perlunicode" includes this:
633          The regular expression compiler produces polymorphic opcodes.  That
634          is, the pattern adapts to the data and automatically switches to
635          the Unicode character scheme when presented with Unicode data--or
636          instead uses a traditional byte scheme when presented with byte
637          data.
639        Sadly, a wide octal escape does not cause a switch, and in a string with
640        no other multibyte characters, these octal escapes are treated as before.
641        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
642        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
643        Unicode string.
645        I have not perpetrated such confusion in PCRE. Up till now, it took just
646        the bottom 8 bits, as in old Perl. I have now made octal escapes with
647        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
648        translate to the appropriate multibyte character.
650    29. Applied some refactoring to reduce the number of warnings from Microsoft
651        and Borland compilers. This has included removing the fudge introduced
652        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
653        a warning about an unused variable.
655    21. PCRE has not included VT (character 0x0b) in the set of whitespace
656        characters since release 4.0, because Perl (from release 5.004) does not.
657        [Or at least, is documented not to: some releases seem to be in conflict
658        with the documentation.] However, when a pattern was studied with
659        pcre_study() and all its branches started with \s, PCRE still included VT
660        as a possible starting character. Of course, this did no harm; it just
661        caused an unnecessary match attempt.
663    22. Removed a now-redundant internal flag bit that recorded the fact that case
664        dependency changed within the pattern. This was once needed for "required
665        byte" processing, but is no longer used. This recovers a now-scarce options
666        bit. Also moved the least significant internal flag bit to the most-
667        significant bit of the word, which was not previously used (hangover from
668        the days when it was an int rather than a uint) to free up another bit for
669        the future.
671    23. Added support for CRLF line endings as well as CR and LF. As well as the
672        default being selectable at build time, it can now be changed at runtime
673        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
674        specify that it is scanning data with non-default line endings.
676    24. Changed the definition of CXXLINK to make it agree with the definition of
677        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
679    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
680        recursions. This makes a big different to stack usage for some patterns.
682    26. If a subpattern containing a named recursion or subroutine reference such
683        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
684        the space required for the compiled pattern went wrong and gave too small a
685        value. Depending on the environment, this could lead to "Failed: internal
686        error: code overflow at offset 49" or "glibc detected double free or
687        corruption" errors.
689    27. Applied patches from Google (a) to support the new newline modes and (b) to
690        advance over multibyte UTF-8 characters in GlobalReplace.
692    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
693        difference for some implementation of PCRE in some Windows version.
695    29. Added some extra testing facilities to pcretest:
697        \q<number>   in a data line sets the "match limit" value
698        \Q<number>   in a data line sets the "match recursion limt" value
699        -S <number>  sets the stack size, where <number> is in megabytes
701        The -S option isn't available for Windows.
704    Version 6.6 06-Feb-06
705    ---------------------
707     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
708        in pcreposix.h. I have copied the definition from pcre.h.
710     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
711        because pcre.h is no longer a built file.
713     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
714        not normally included in the compiled code.
717    Version 6.5 01-Feb-06
718    ---------------------
720     1. When using the partial match feature with pcre_dfa_exec(), it was not
721        anchoring the second and subsequent partial matches at the new starting
722        point. This could lead to incorrect results. For example, with the pattern
723        /1234/, partially matching against "123" and then "a4" gave a match.
725     2. Changes to pcregrep:
727        (a) All non-match returns from pcre_exec() were being treated as failures
728            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
729            error message is output. Some extra information is given for the
730            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
731            probably the only errors that are likely to be caused by users (by
732            specifying a regex that has nested indefinite repeats, for instance).
733            If there are more than 20 of these errors, pcregrep is abandoned.
735        (b) A binary zero was treated as data while matching, but terminated the
736            output line if it was written out. This has been fixed: binary zeroes
737            are now no different to any other data bytes.
739        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
740            used to set a locale for matching. The --locale=xxxx long option has
741            been added (no short equivalent) to specify a locale explicitly on the
742            pcregrep command, overriding the environment variables.
744        (d) When -B was used with -n, some line numbers in the output were one less
745            than they should have been.
747        (e) Added the -o (--only-matching) option.
749        (f) If -A or -C was used with -c (count only), some lines of context were
750            accidentally printed for the final match.
752        (g) Added the -H (--with-filename) option.
754        (h) The combination of options -rh failed to suppress file names for files
755            that were found from directory arguments.
757        (i) Added the -D (--devices) and -d (--directories) options.
759        (j) Added the -F (--fixed-strings) option.
761        (k) Allow "-" to be used as a file name for -f as well as for a data file.
763        (l) Added the --colo(u)r option.
765        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
766            is not present by default.
768     3. A nasty bug was discovered in the handling of recursive patterns, that is,
769        items such as (?R) or (?1), when the recursion could match a number of
770        alternatives. If it matched one of the alternatives, but subsequently,
771        outside the recursion, there was a failure, the code tried to back up into
772        the recursion. However, because of the way PCRE is implemented, this is not
773        possible, and the result was an incorrect result from the match.
775        In order to prevent this happening, the specification of recursion has
776        been changed so that all such subpatterns are automatically treated as
777        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
779     4. I had overlooked the fact that, in some locales, there are characters for
780        which isalpha() is true but neither isupper() nor islower() are true. In
781        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
782        and ordfeminine) are like this. This affected the treatment of \w and \W
783        when they appeared in character classes, but not when they appeared outside
784        a character class. The bit map for "word" characters is now created
785        separately from the results of isalnum() instead of just taking it from the
786        upper, lower, and digit maps. (Plus the underscore character, of course.)
788     5. The above bug also affected the handling of POSIX character classes such as
789        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
790        permanent tables. Instead, the bit maps for such a class were previously
791        created as the appropriate unions of the upper, lower, and digit bitmaps.
792        Now they are created by subtraction from the [[:word:]] class, which has
793        its own bitmap.
795     6. The [[:blank:]] character class matches horizontal, but not vertical space.
796        It is created by subtracting the vertical space characters (\x09, \x0a,
797        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
798        subtraction was done in the overall bitmap for a character class, meaning
799        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
800        be recognized. This bug has been fixed.
802     7. Patches from the folks at Google:
804          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
805          real life, but is still worth protecting against".
807          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
808          regular expressions".
810          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
811          have it.
813          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
814          "configure" and the latter not, in order to fix a problem somebody had
815          with compiling the Arg class on HP-UX.
817          (e) Improve the error-handling of the C++ wrapper a little bit.
819          (f) New tests for checking recursion limiting.
821     8. The pcre_memmove() function, which is used only if the environment does not
822        have a standard memmove() function (and is therefore rarely compiled),
823        contained two bugs: (a) use of int instead of size_t, and (b) it was not
824        returning a result (though PCRE never actually uses the result).
826     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
827        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
828        returned instead of calling malloc() with an overflowing number that would
829        most likely cause subsequent chaos.
831    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
833    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
834        with this option is matched, the nmatch and pmatch options of regexec() are
835        ignored.
837    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
838        provided in case anyone wants to the the POSIX interface with UTF-8
839        strings.
841    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
842        C++ linking (needed for some HP-UX environments).
844    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
845        (unused parameter) and in the pcre_printint() function (omitted "default"
846        switch label when the default is to do nothing).
848    15. Added some code to make it possible, when PCRE is compiled as a C++
849        library, to replace subject pointers for pcre_exec() with a smart pointer
850        class, thus making it possible to process discontinuous strings.
852    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
853        much the same function. They were added by different people who were trying
854        to make PCRE easy to compile on non-Unix systems. It has been suggested
855        that PCRE_EXPORT be abolished now that there is more automatic apparatus
856        for compiling on Windows systems. I have therefore replaced it with
857        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
858        defaults to "extern" for C or "extern C" for C++, which works fine on
859        Unix-like systems. It is now possible to override the value of PCRE_DATA_
860        SCOPE with something explicit in config.h. In addition:
862        (a) pcreposix.h still had just "extern" instead of either of these macros;
863            I have replaced it with PCRE_DATA_SCOPE.
865        (b) Functions such as _pcre_xclass(), which are internal to the library,
866            but external in the C sense, all had PCRE_EXPORT in their definitions.
867            This is apparently wrong for the Windows case, so I have removed it.
868            (It makes no difference on Unix-like systems.)
870    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
871        of recursive calls to match(). This is different to MATCH_LIMIT because
872        that limits the total number of calls to match(), not all of which increase
873        the depth of recursion. Limiting the recursion depth limits the amount of
874        stack (or heap if NO_RECURSE is set) that is used. The default can be set
875        when PCRE is compiled, and changed at run time. A patch from Google adds
876        this functionality to the C++ interface.
878    18. Changes to the handling of Unicode character properties:
880        (a) Updated the table to Unicode 4.1.0.
882        (b) Recognize characters that are not in the table as "Cn" (undefined).
884        (c) I revised the way the table is implemented to a much improved format
885            which includes recognition of ranges. It now supports the ranges that
886            are defined in UnicodeData.txt, and it also amalgamates other
887            characters into ranges. This has reduced the number of entries in the
888            table from around 16,000 to around 3,000, thus reducing its size
889            considerably. I realized I did not need to use a tree structure after
890            all - a binary chop search is just as efficient. Having reduced the
891            number of entries, I extended their size from 6 bytes to 8 bytes to
892            allow for more data.
894        (d) Added support for Unicode script names via properties such as \p{Han}.
896    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
897        matching that character.
899    20. When matching a repeated Unicode property with a minimum greater than zero,
900        (for example \pL{2,}), PCRE could look past the end of the subject if it
901        reached it while seeking the minimum number of characters. This could
902        happen only if some of the characters were more than one byte long, because
903        there is a check for at least the minimum number of bytes.
905    21. Refactored the implementation of \p and \P so as to be more general, to
906        allow for more different types of property in future. This has changed the
907        compiled form incompatibly. Anybody with saved compiled patterns that use
908        \p or \P will have to recompile them.
910    22. Added "Any" and "L&" to the supported property types.
912    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
913        but give a compile time error if the value is greater than 0xff.
915    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
916        accidentally not being installed or uninstalled.
918    25. The pcre.h file was built from pcre.h.in, but the only changes that were
919        made were to insert the current release number. This seemed silly, because
920        it made things harder for people building PCRE on systems that don't run
921        "configure". I have turned pcre.h into a distributed file, no longer built
922        by "configure", with the version identification directly included. There is
923        no longer a pcre.h.in file.
925        However, this change necessitated a change to the pcre-config script as
926        well. It is built from pcre-config.in, and one of the substitutions was the
927        release number. I have updated configure.ac so that ./configure now finds
928        the release number by grepping pcre.h.
930    26. Added the ability to run the tests under valgrind.
933    Version 6.4 05-Sep-05
934    ---------------------
936     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
937        "--" to be printed when multiple files were scanned, even when none of the
938        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
939        consider it to be a bug, and have restored the previous behaviour.
941     2. A couple of code tidies to get rid of compiler warnings.
943     3. The pcretest program used to cheat by referring to symbols in the library
944        whose names begin with _pcre_. These are internal symbols that are not
945        really supposed to be visible externally, and in some environments it is
946        possible to suppress them. The cheating is now confined to including
947        certain files from the library's source, which is a bit cleaner.
949     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
950        file's purpose clearer.
952     5. Reorganized pcre_ucp_findchar().
955  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
956  ---------------------  ---------------------

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