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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.
31    Version 7.2 19-Jun-07
32    ---------------------
34     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
35        which is apparently normally available under Windows.
37     2. Re-jig the pcregrep tests with different newline settings in an attempt
38        to make them independent of the local environment's newline setting.
40     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
42     4. Some of the "internals" tests were previously cut out when the link size
43        was not 2, because the output contained actual offsets. The recent new
44        "Z" feature of pcretest means that these can be cut out, making the tests
45        usable with all link sizes.
47     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
48        stack recursion. This gives a massive performance boost under BSD, but just
49        a small improvement under Linux. However, it saves one field in the frame
50        in all cases.
52     6. Added more features from the forthcoming Perl 5.10:
54        (a) (?-n) (where n is a string of digits) is a relative subroutine or
55            recursion call. It refers to the nth most recently opened parentheses.
57        (b) (?+n) is also a relative subroutine call; it refers to the nth next
58            to be opened parentheses.
60        (c) Conditions that refer to capturing parentheses can be specified
61            relatively, for example, (?(-2)... or (?(+3)...
63        (d) \K resets the start of the current match so that everything before
64            is not part of it.
66        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
68        (f) \g{name} is another synonym - part of Perl 5.10's unification of
69            reference syntax.
71        (g) (?| introduces a group in which the numbering of parentheses in each
72            alternative starts with the same number.
74        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
76     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
79     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
80        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
81        for detecting groups that can match an empty string.
83     9. A pattern with a very large number of alternatives (more than several
84        hundred) was running out of internal workspace during the pre-compile
85        phase, where pcre_compile() figures out how much memory will be needed. A
86        bit of new cunning has reduced the workspace needed for groups with
87        alternatives. The 1000-alternative test pattern now uses 12 bytes of
88        workspace instead of running out of the 4096 that are available.
90    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
92    11. Applied patch from Google to remove an optimization that didn't quite work.
93        The report of the bug said:
95          pcrecpp::RE("a*").FullMatch("aaa") matches, while
96          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
97          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
99    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
100        it matched the wrong number of bytes.
103    Version 7.1 24-Apr-07
104    ---------------------
106     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
107        that is more "standard", making use of automake and other Autotools. There
108        is some re-arrangement of the files and adjustment of comments consequent
109        on this.
111     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
112        for recursive directory scanning broke on some systems because the files
113        are not scanned in any specific order and on different systems the order
114        was different. A call to "sort" has been inserted into RunGrepTest for the
115        approprate test as a short-term fix. In the longer term there may be an
116        alternative.
118     3. I had an email from Eric Raymond about problems translating some of PCRE's
119        man pages to HTML (despite the fact that I distribute HTML pages, some
120        people do their own conversions for various reasons). The problems
121        concerned the use of low-level troff macros .br and .in. I have therefore
122        removed all such uses from the man pages (some were redundant, some could
123        be replaced by .nf/.fi pairs). The 132html script that I use to generate
124        HTML has been updated to handle .nf/.fi and to complain if it encounters
125        .br or .in.
127     4. Updated comments in configure.ac that get placed in config.h.in and also
128        arranged for config.h to be included in the distribution, with the name
129        config.h.generic, for the benefit of those who have to compile without
130        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
132     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
133        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
134        makevp.bat for the current PCRE, using the additional files
135        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
137     6. A Windows user reported a minor discrepancy with test 2, which turned out
138        to be caused by a trailing space on an input line that had got lost in his
139        copy. The trailing space was an accident, so I've just removed it.
141     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
142        that is needed.
144     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
145        as "const" (a) because they are and (b) because it helps the PHP
146        maintainers who have recently made a script to detect big data structures
147        in the php code that should be moved to the .rodata section. I remembered
148        to update Builducptable as well, so it won't revert if ucptable.h is ever
149        re-created.
151     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
152        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
153        order to be able to cut out the UTF-8 tables in the latter when UTF-8
154        support is not required. This saves 1.5-2K of code, which is important in
155        some applications.
157        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
158        so as not to refer to the tables, even though these functions will never be
159        called when UTF-8 support is disabled. Otherwise there are problems with a
160        shared library.
162    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
164        (a) It was defining its arguments as char * instead of void *.
166        (b) It was assuming that all moves were upwards in memory; this was true
167            a long time ago when I wrote it, but is no longer the case.
169        The emulated memove() is provided for those environments that have neither
170        memmove() nor bcopy(). I didn't think anyone used it these days, but that
171        is clearly not the case, as these two bugs were recently reported.
173    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
174        and Detrail to create the HTML documentation, the .txt form of the man
175        pages, and it removes trailing spaces from listed files. It also creates
176        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
177        case, it wraps all the #defines with #ifndefs. This script should be run
178        before "make dist".
180    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
181        with Unicode property support.
183        (a) For a maximizing quantifier, if the two different cases of the
184            character were of different lengths in their UTF-8 codings (there are
185            some cases like this - I found 11), and the matching function had to
186            back up over a mixture of the two cases, it incorrectly assumed they
187            were both the same length.
189        (b) When PCRE was configured to use the heap rather than the stack for
190            recursion during matching, it was not correctly preserving the data for
191            the other case of a UTF-8 character when checking ahead for a match
192            while processing a minimizing repeat. If the check also involved
193            matching a wide character, but failed, corruption could cause an
194            erroneous result when trying to check for a repeat of the original
195            character.
197    13. Some tidying changes to the testing mechanism:
199        (a) The RunTest script now detects the internal link size and whether there
200            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
201            values substituted by "configure". (The RunGrepTest script already did
202            this for UTF-8.) The configure.ac script no longer substitutes the
203            relevant variables.
205        (b) The debugging options /B and /D in pcretest show the compiled bytecode
206            with length and offset values. This means that the output is different
207            for different internal link sizes. Test 2 is skipped for link sizes
208            other than 2 because of this, bypassing the problem. Unfortunately,
209            there was also a test in test 3 (the locale tests) that used /B and
210            failed for link sizes other than 2. Rather than cut the whole test out,
211            I have added a new /Z option to pcretest that replaces the length and
212            offset values with spaces. This is now used to make test 3 independent
213            of link size. (Test 2 will be tidied up later.)
215    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
216        segmentation fault instead of returning the appropriate error message.
218    15. In multiline mode when the newline sequence was set to "any", the pattern
219        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
220        This doesn't seem right; it now treats the CRLF combination as the line
221        ending, and so does not match in that case. It's only a pattern such as ^$
222        that would hit this one: something like ^ABC$ would have failed after \r
223        and then tried again after \r\n.
225    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
226        in an attempt to make files that differ only in their line terminators
227        compare equal. This works on Linux.
229    17. Under certain error circumstances pcregrep might try to free random memory
230        as it exited. This is now fixed, thanks to valgrind.
232    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
233        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
234        was because its rules for how to advance for /g after matching an empty
235        string at the end of a line did not allow for this case. They now check for
236        it specially.
238    20. pcretest is supposed to handle patterns and data of any length, by
239        extending its buffers when necessary. It was getting this wrong when the
240        buffer for a data line had to be extended.
242    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
243        CRLF as a newline sequence.
245    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
246        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
247        I have nevertheless tidied it up.
249    23. Added some casts to kill warnings from HP-UX ia64 compiler.
251    24. Added a man page for pcre-config.
254    Version 7.0 19-Dec-06
255    ---------------------
257     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
258        moving to gcc 4.1.1.
260     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
261        sys/time.h, which is documented as needed for this function. It doesn't
262        seem to matter on Linux, but it showed up on some releases of OS X.
264     3. It seems that there are systems where bytes whose values are greater than
265        127 match isprint() in the "C" locale. The "C" locale should be the
266        default when a C program starts up. In most systems, only ASCII printing
267        characters match isprint(). This difference caused the output from pcretest
268        to vary, making some of the tests fail. I have changed pcretest so that:
270        (a) When it is outputting text in the compiled version of a pattern, bytes
271            other than 32-126 are always shown as hex escapes.
273        (b) When it is outputting text that is a matched part of a subject string,
274            it does the same, unless a different locale has been set for the match
275            (using the /L modifier). In this case, it uses isprint() to decide.
277     4. Fixed a major bug that caused incorrect computation of the amount of memory
278        required for a compiled pattern when options that changed within the
279        pattern affected the logic of the preliminary scan that determines the
280        length. The relevant options are -x, and -i in UTF-8 mode. The result was
281        that the computed length was too small. The symptoms of this bug were
282        either the PCRE error "internal error: code overflow" from pcre_compile(),
283        or a glibc crash with a message such as "pcretest: free(): invalid next
284        size (fast)". Examples of patterns that provoked this bug (shown in
285        pcretest format) are:
287          /(?-x: )/x
288          /(?x)(?-x: \s*#\s*)/
289          /((?i)[\x{c0}])/8
290          /(?i:[\x{c0}])/8
292        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
293        is now done differently.
295     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
296        wrapper classes; (b) implement a new function in the C++ scanner that is
297        more efficient than the old way of doing things because it avoids levels of
298        recursion in the regex matching; (c) add a paragraph to the documentation
299        for the FullMatch() function.
301     6. The escape sequence \n was being treated as whatever was defined as
302        "newline". Not only was this contrary to the documentation, which states
303        that \n is character 10 (hex 0A), but it also went horribly wrong when
304        "newline" was defined as CRLF. This has been fixed.
306     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
307        was being set to -1 for the "end of line" case (supposedly a value that no
308        character can have). Though this value is never used (the check for end of
309        line is "zero bytes in current character"), it caused compiler complaints.
310        I've changed it to 0xffffffff.
312     8. In pcre_version.c, the version string was being built by a sequence of
313        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
314        string (as it is for production releases) called a macro with an empty
315        argument. The C standard says the result of this is undefined. The gcc
316        compiler treats it as an empty string (which was what was wanted) but it is
317        reported that Visual C gives an error. The source has been hacked around to
318        avoid this problem.
320     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
321        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
322        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
323        of them did).
325    10. Originally, pcretest opened its input and output without "b"; then I was
326        told that "b" was needed in some environments, so it was added for release
327        5.0 to both the input and output. (It makes no difference on Unix-like
328        systems.) Later I was told that it is wrong for the input on Windows. I've
329        now abstracted the modes into two macros, to make it easier to fiddle with
330        them, and removed "b" from the input mode under Windows.
332    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
334    12. Added -help and --help to pcretest as an official way of being reminded
335        of the options.
337    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
338        and pcrecpp.cc because they annoy compilers at high warning levels.
340    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
342    15. Fixed an occurrence of == in configure.ac that should have been = (shell
343        scripts are not C programs :-) and which was not noticed because it works
344        on Linux.
346    16. pcretest is supposed to handle any length of pattern and data line (as one
347        line or as a continued sequence of lines) by extending its input buffer if
348        necessary. This feature was broken for very long pattern lines, leading to
349        a string of junk being passed to pcre_compile() if the pattern was longer
350        than about 50K.
352    17. I have done a major re-factoring of the way pcre_compile() computes the
353        amount of memory needed for a compiled pattern. Previously, there was code
354        that made a preliminary scan of the pattern in order to do this. That was
355        OK when PCRE was new, but as the facilities have expanded, it has become
356        harder and harder to keep it in step with the real compile phase, and there
357        have been a number of bugs (see for example, 4 above). I have now found a
358        cunning way of running the real compile function in a "fake" mode that
359        enables it to compute how much memory it would need, while actually only
360        ever using a few hundred bytes of working memory and without too many
361        tests of the mode. This should make future maintenance and development
362        easier. A side effect of this work is that the limit of 200 on the nesting
363        depth of parentheses has been removed (though this was never a serious
364        limitation, I suspect). However, there is a downside: pcre_compile() now
365        runs more slowly than before (30% or more, depending on the pattern). I
366        hope this isn't a big issue. There is no effect on runtime performance.
368    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
369        newline (only possible for the last line of a file) and it was a
370        pattern that set a locale (followed by /Lsomething), pcretest crashed.
372    19. Added additional timing features to pcretest. (1) The -tm option now times
373        matching only, not compiling. (2) Both -t and -tm can be followed, as a
374        separate command line item, by a number that specifies the number of
375        repeats to use when timing. The default is 50000; this gives better
376        precision, but takes uncomfortably long for very large patterns.
378    20. Extended pcre_study() to be more clever in cases where a branch of a
379        subpattern has no definite first character. For example, (a*|b*)[cd] would
380        previously give no result from pcre_study(). Now it recognizes that the
381        first character must be a, b, c, or d.
383    21. There was an incorrect error "recursive call could loop indefinitely" if
384        a subpattern (or the entire pattern) that was being tested for matching an
385        empty string contained only one non-empty item after a nested subpattern.
386        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
387        incorrectly, because the \d was being skipped in the check.
389    22. The pcretest program now has a new pattern option /B and a command line
390        option -b, which is equivalent to adding /B to every pattern. This causes
391        it to show the compiled bytecode, without the additional information that
392        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
393        is the same as /B/I).
395    23. A new optimization is now able automatically to treat some sequences such
396        as a*b as a*+b. More specifically, if something simple (such as a character
397        or a simple class like \d) has an unlimited quantifier, and is followed by
398        something that cannot possibly match the quantified thing, the quantifier
399        is automatically "possessified".
401    24. A recursive reference to a subpattern whose number was greater than 39
402        went wrong under certain circumstances in UTF-8 mode. This bug could also
403        have affected the operation of pcre_study().
405    25. Realized that a little bit of performance could be had by replacing
406        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
408    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
410    27. Possessive quantifiers such as a++ were previously implemented by turning
411        them into atomic groups such as ($>a+). Now they have their own opcodes,
412        which improves performance. This includes the automatically created ones
413        from 23 above.
415    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
416        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
417        the first matched character to be a colon. This applied both to named and
418        numbered groups.
420    29. The ucpinternal.h header file was missing its idempotency #ifdef.
422    30. I was sent a "project" file called libpcre.a.dev which I understand makes
423        building PCRE on Windows easier, so I have included it in the distribution.
425    31. There is now a check in pcretest against a ridiculously large number being
426        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
427        loop, the loop is abandoned.
429    32. Forward references to subpatterns in conditions such as (?(2)...) where
430        subpattern 2 is defined later cause pcre_compile() to search forwards in
431        the pattern for the relevant set of parentheses. This search went wrong
432        when there were unescaped parentheses in a character class, parentheses
433        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
435    33. "Subroutine" calls and backreferences were previously restricted to
436        referencing subpatterns earlier in the regex. This restriction has now
437        been removed.
439    34. Added a number of extra features that are going to be in Perl 5.10. On the
440        whole, these are just syntactic alternatives for features that PCRE had
441        previously implemented using the Python syntax or my own invention. The
442        other formats are all retained for compatibility.
444        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
445            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
446            also .NET compatible.
448        (b) A recursion or subroutine call to a named group can now be defined as
449            (?&name) as well as (?P>name).
451        (c) A backreference to a named group can now be defined as \k<name> or
452            \k'name' as well as (?P=name). The new forms, as well as being in Perl
453            5.10, are also .NET compatible.
455        (d) A conditional reference to a named group can now use the syntax
456            (?(<name>) or (?('name') as well as (?(name).
458        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
459            groups (named and numbered) that are never evaluated inline, but can be
460            called as "subroutines" from elsewhere. In effect, the DEFINE condition
461            is always false. There may be only one alternative in such a group.
463        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
464            as the simple (?(R). The condition is true only if the most recent
465            recursion is that of the given number or name. It does not search out
466            through the entire recursion stack.
468        (g) The escape \gN or \g{N} has been added, where N is a positive or
469            negative number, specifying an absolute or relative reference.
471    35. Tidied to get rid of some further signed/unsigned compiler warnings and
472        some "unreachable code" warnings.
474    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
475        things, this adds five new scripts.
477    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
478        There were also incompatibilities regarding the handling of \Q..\E inside
479        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
480        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
482    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
483        matches an empty string, and forcibly breaks the loop. There were bugs in
484        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
485        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
486        separate and independent bugs (that affected different cases) have been
487        fixed.
489    39. Refactored the code to abolish the use of different opcodes for small
490        capturing bracket numbers. This is a tidy that I avoided doing when I
491        removed the limit on the number of capturing brackets for 3.5 back in 2001.
492        The new approach is not only tidier, it makes it possible to reduce the
493        memory needed to fix the previous bug (38).
495    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
496        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
497        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
498        mode.
500    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
501        report.
503    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
504        copy construction and assignment in the C++ wrapper.
506    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
507        couple of bugs that could have given wrong results in the "--newline=crlf"
508        case.
510    44. Added a number of casts and did some reorganization of signed/unsigned int
511        variables following suggestions from Dair Grant. Also renamed the variable
512        "this" as "item" because it is a C++ keyword.
514    45. Arranged for dftables to add
516          #include "pcre_internal.h"
518        to pcre_chartables.c because without it, gcc 4.x may remove the array
519        definition from the final binary if PCRE is built into a static library and
520        dead code stripping is activated.
522    46. For an unanchored pattern, if a match attempt fails at the start of a
523        newline sequence, and the newline setting is CRLF or ANY, and the next two
524        characters are CRLF, advance by two characters instead of one.
527    Version 6.7 04-Jul-06
528    ---------------------
530     1. In order to handle tests when input lines are enormously long, pcretest has
531        been re-factored so that it automatically extends its buffers when
532        necessary. The code is crude, but this _is_ just a test program. The
533        default size has been increased from 32K to 50K.
535     2. The code in pcre_study() was using the value of the re argument before
536        testing it for NULL. (Of course, in any sensible call of the function, it
537        won't be NULL.)
539     3. The memmove() emulation function in pcre_internal.h, which is used on
540        systems that lack both memmove() and bcopy() - that is, hardly ever -
541        was missing a "static" storage class specifier.
543     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
544        containing an extended class (one that cannot be represented by a bitmap
545        because it contains high-valued characters or Unicode property items, e.g.
546        [\pZ]). Almost always one would set UTF-8 mode when processing such a
547        pattern, but PCRE should not loop if you do not (it no longer does).
548        [Detail: two cases were found: (a) a repeated subpattern containing an
549        extended class; (b) a recursive reference to a subpattern that followed a
550        previous extended class. It wasn't skipping over the extended class
551        correctly when UTF-8 mode was not set.]
553     5. A negated single-character class was not being recognized as fixed-length
554        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
555        compile error "lookbehind assertion is not fixed length".
557     6. The RunPerlTest auxiliary script was showing an unexpected difference
558        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
559        write a Perl script that can interpret lines of an input file either as
560        byte characters or as UTF-8, which is what "perltest" was being required to
561        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
562        can't do is switch easily at run time between having the "use utf8;" pragma
563        or not. In the end, I fudged it by using the RunPerlTest script to insert
564        "use utf8;" explicitly for the UTF-8 tests.
566     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
567        the end of the subject string, contrary to the documentation and to what
568        Perl does. This was true of both matching functions. Now it matches only at
569        the start of the subject and immediately after *internal* newlines.
571     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
572        a pointer to an int instead of a pointer to an unsigned long int. This
573        caused problems on 64-bit systems.
575     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
576        instance of the 'standard' template library not being so standard".
578    10. There was no check on the number of named subpatterns nor the maximum
579        length of a subpattern name. The product of these values is used to compute
580        the size of the memory block for a compiled pattern. By supplying a very
581        long subpattern name and a large number of named subpatterns, the size
582        computation could be caused to overflow. This is now prevented by limiting
583        the length of names to 32 characters, and the number of named subpatterns
584        to 10,000.
586    11. Subpatterns that are repeated with specific counts have to be replicated in
587        the compiled pattern. The size of memory for this was computed from the
588        length of the subpattern and the repeat count. The latter is limited to
589        65535, but there was no limit on the former, meaning that integer overflow
590        could in principle occur. The compiled length of a repeated subpattern is
591        now limited to 30,000 bytes in order to prevent this.
593    12. Added the optional facility to have named substrings with the same name.
595    13. Added the ability to use a named substring as a condition, using the
596        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
597        are numbers (not recommended). Forward references are permitted.
599    14. Added forward references in named backreferences (if you see what I mean).
601    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
602        pattern could run off the end of the subject. For example, the pattern
603        "(?s)(.{1,5})"8 did this with the subject "ab".
605    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
606        PCRE_CASELESS was set when matching characters that were quantified with ?
607        or *.
609    17. A character class other than a single negated character that had a minimum
610        but no maximum quantifier - for example [ab]{6,} - was not handled
611        correctly by pce_dfa_exec(). It would match only one character.
613    18. A valid (though odd) pattern that looked like a POSIX character
614        class but used an invalid character after [ (for example [[,abc,]]) caused
615        pcre_compile() to give the error "Failed: internal error: code overflow" or
616        in some cases to crash with a glibc free() error. This could even happen if
617        the pattern terminated after [[ but there just happened to be a sequence of
618        letters, a binary zero, and a closing ] in the memory that followed.
620    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
621        over the years. Originally (before any Unicode support), just the bottom 8
622        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
623        output from "man perlunicode" includes this:
625          The regular expression compiler produces polymorphic opcodes.  That
626          is, the pattern adapts to the data and automatically switches to
627          the Unicode character scheme when presented with Unicode data--or
628          instead uses a traditional byte scheme when presented with byte
629          data.
631        Sadly, a wide octal escape does not cause a switch, and in a string with
632        no other multibyte characters, these octal escapes are treated as before.
633        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
634        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
635        Unicode string.
637        I have not perpetrated such confusion in PCRE. Up till now, it took just
638        the bottom 8 bits, as in old Perl. I have now made octal escapes with
639        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
640        translate to the appropriate multibyte character.
642    29. Applied some refactoring to reduce the number of warnings from Microsoft
643        and Borland compilers. This has included removing the fudge introduced
644        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
645        a warning about an unused variable.
647    21. PCRE has not included VT (character 0x0b) in the set of whitespace
648        characters since release 4.0, because Perl (from release 5.004) does not.
649        [Or at least, is documented not to: some releases seem to be in conflict
650        with the documentation.] However, when a pattern was studied with
651        pcre_study() and all its branches started with \s, PCRE still included VT
652        as a possible starting character. Of course, this did no harm; it just
653        caused an unnecessary match attempt.
655    22. Removed a now-redundant internal flag bit that recorded the fact that case
656        dependency changed within the pattern. This was once needed for "required
657        byte" processing, but is no longer used. This recovers a now-scarce options
658        bit. Also moved the least significant internal flag bit to the most-
659        significant bit of the word, which was not previously used (hangover from
660        the days when it was an int rather than a uint) to free up another bit for
661        the future.
663    23. Added support for CRLF line endings as well as CR and LF. As well as the
664        default being selectable at build time, it can now be changed at runtime
665        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
666        specify that it is scanning data with non-default line endings.
668    24. Changed the definition of CXXLINK to make it agree with the definition of
669        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
671    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
672        recursions. This makes a big different to stack usage for some patterns.
674    26. If a subpattern containing a named recursion or subroutine reference such
675        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
676        the space required for the compiled pattern went wrong and gave too small a
677        value. Depending on the environment, this could lead to "Failed: internal
678        error: code overflow at offset 49" or "glibc detected double free or
679        corruption" errors.
681    27. Applied patches from Google (a) to support the new newline modes and (b) to
682        advance over multibyte UTF-8 characters in GlobalReplace.
684    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
685        difference for some implementation of PCRE in some Windows version.
687    29. Added some extra testing facilities to pcretest:
689        \q<number>   in a data line sets the "match limit" value
690        \Q<number>   in a data line sets the "match recursion limt" value
691        -S <number>  sets the stack size, where <number> is in megabytes
693        The -S option isn't available for Windows.
696    Version 6.6 06-Feb-06
697    ---------------------
699     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
700        in pcreposix.h. I have copied the definition from pcre.h.
702     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
703        because pcre.h is no longer a built file.
705     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
706        not normally included in the compiled code.
709    Version 6.5 01-Feb-06
710    ---------------------
712     1. When using the partial match feature with pcre_dfa_exec(), it was not
713        anchoring the second and subsequent partial matches at the new starting
714        point. This could lead to incorrect results. For example, with the pattern
715        /1234/, partially matching against "123" and then "a4" gave a match.
717     2. Changes to pcregrep:
719        (a) All non-match returns from pcre_exec() were being treated as failures
720            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
721            error message is output. Some extra information is given for the
722            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
723            probably the only errors that are likely to be caused by users (by
724            specifying a regex that has nested indefinite repeats, for instance).
725            If there are more than 20 of these errors, pcregrep is abandoned.
727        (b) A binary zero was treated as data while matching, but terminated the
728            output line if it was written out. This has been fixed: binary zeroes
729            are now no different to any other data bytes.
731        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
732            used to set a locale for matching. The --locale=xxxx long option has
733            been added (no short equivalent) to specify a locale explicitly on the
734            pcregrep command, overriding the environment variables.
736        (d) When -B was used with -n, some line numbers in the output were one less
737            than they should have been.
739        (e) Added the -o (--only-matching) option.
741        (f) If -A or -C was used with -c (count only), some lines of context were
742            accidentally printed for the final match.
744        (g) Added the -H (--with-filename) option.
746        (h) The combination of options -rh failed to suppress file names for files
747            that were found from directory arguments.
749        (i) Added the -D (--devices) and -d (--directories) options.
751        (j) Added the -F (--fixed-strings) option.
753        (k) Allow "-" to be used as a file name for -f as well as for a data file.
755        (l) Added the --colo(u)r option.
757        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
758            is not present by default.
760     3. A nasty bug was discovered in the handling of recursive patterns, that is,
761        items such as (?R) or (?1), when the recursion could match a number of
762        alternatives. If it matched one of the alternatives, but subsequently,
763        outside the recursion, there was a failure, the code tried to back up into
764        the recursion. However, because of the way PCRE is implemented, this is not
765        possible, and the result was an incorrect result from the match.
767        In order to prevent this happening, the specification of recursion has
768        been changed so that all such subpatterns are automatically treated as
769        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
771     4. I had overlooked the fact that, in some locales, there are characters for
772        which isalpha() is true but neither isupper() nor islower() are true. In
773        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
774        and ordfeminine) are like this. This affected the treatment of \w and \W
775        when they appeared in character classes, but not when they appeared outside
776        a character class. The bit map for "word" characters is now created
777        separately from the results of isalnum() instead of just taking it from the
778        upper, lower, and digit maps. (Plus the underscore character, of course.)
780     5. The above bug also affected the handling of POSIX character classes such as
781        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
782        permanent tables. Instead, the bit maps for such a class were previously
783        created as the appropriate unions of the upper, lower, and digit bitmaps.
784        Now they are created by subtraction from the [[:word:]] class, which has
785        its own bitmap.
787     6. The [[:blank:]] character class matches horizontal, but not vertical space.
788        It is created by subtracting the vertical space characters (\x09, \x0a,
789        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
790        subtraction was done in the overall bitmap for a character class, meaning
791        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
792        be recognized. This bug has been fixed.
794     7. Patches from the folks at Google:
796          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
797          real life, but is still worth protecting against".
799          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
800          regular expressions".
802          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
803          have it.
805          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
806          "configure" and the latter not, in order to fix a problem somebody had
807          with compiling the Arg class on HP-UX.
809          (e) Improve the error-handling of the C++ wrapper a little bit.
811          (f) New tests for checking recursion limiting.
813     8. The pcre_memmove() function, which is used only if the environment does not
814        have a standard memmove() function (and is therefore rarely compiled),
815        contained two bugs: (a) use of int instead of size_t, and (b) it was not
816        returning a result (though PCRE never actually uses the result).
818     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
819        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
820        returned instead of calling malloc() with an overflowing number that would
821        most likely cause subsequent chaos.
823    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
825    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
826        with this option is matched, the nmatch and pmatch options of regexec() are
827        ignored.
829    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
830        provided in case anyone wants to the the POSIX interface with UTF-8
831        strings.
833    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
834        C++ linking (needed for some HP-UX environments).
836    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
837        (unused parameter) and in the pcre_printint() function (omitted "default"
838        switch label when the default is to do nothing).
840    15. Added some code to make it possible, when PCRE is compiled as a C++
841        library, to replace subject pointers for pcre_exec() with a smart pointer
842        class, thus making it possible to process discontinuous strings.
844    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
845        much the same function. They were added by different people who were trying
846        to make PCRE easy to compile on non-Unix systems. It has been suggested
847        that PCRE_EXPORT be abolished now that there is more automatic apparatus
848        for compiling on Windows systems. I have therefore replaced it with
849        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
850        defaults to "extern" for C or "extern C" for C++, which works fine on
851        Unix-like systems. It is now possible to override the value of PCRE_DATA_
852        SCOPE with something explicit in config.h. In addition:
854        (a) pcreposix.h still had just "extern" instead of either of these macros;
855            I have replaced it with PCRE_DATA_SCOPE.
857        (b) Functions such as _pcre_xclass(), which are internal to the library,
858            but external in the C sense, all had PCRE_EXPORT in their definitions.
859            This is apparently wrong for the Windows case, so I have removed it.
860            (It makes no difference on Unix-like systems.)
862    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
863        of recursive calls to match(). This is different to MATCH_LIMIT because
864        that limits the total number of calls to match(), not all of which increase
865        the depth of recursion. Limiting the recursion depth limits the amount of
866        stack (or heap if NO_RECURSE is set) that is used. The default can be set
867        when PCRE is compiled, and changed at run time. A patch from Google adds
868        this functionality to the C++ interface.
870    18. Changes to the handling of Unicode character properties:
872        (a) Updated the table to Unicode 4.1.0.
874        (b) Recognize characters that are not in the table as "Cn" (undefined).
876        (c) I revised the way the table is implemented to a much improved format
877            which includes recognition of ranges. It now supports the ranges that
878            are defined in UnicodeData.txt, and it also amalgamates other
879            characters into ranges. This has reduced the number of entries in the
880            table from around 16,000 to around 3,000, thus reducing its size
881            considerably. I realized I did not need to use a tree structure after
882            all - a binary chop search is just as efficient. Having reduced the
883            number of entries, I extended their size from 6 bytes to 8 bytes to
884            allow for more data.
886        (d) Added support for Unicode script names via properties such as \p{Han}.
888    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
889        matching that character.
891    20. When matching a repeated Unicode property with a minimum greater than zero,
892        (for example \pL{2,}), PCRE could look past the end of the subject if it
893        reached it while seeking the minimum number of characters. This could
894        happen only if some of the characters were more than one byte long, because
895        there is a check for at least the minimum number of bytes.
897    21. Refactored the implementation of \p and \P so as to be more general, to
898        allow for more different types of property in future. This has changed the
899        compiled form incompatibly. Anybody with saved compiled patterns that use
900        \p or \P will have to recompile them.
902    22. Added "Any" and "L&" to the supported property types.
904    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
905        but give a compile time error if the value is greater than 0xff.
907    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
908        accidentally not being installed or uninstalled.
910    25. The pcre.h file was built from pcre.h.in, but the only changes that were
911        made were to insert the current release number. This seemed silly, because
912        it made things harder for people building PCRE on systems that don't run
913        "configure". I have turned pcre.h into a distributed file, no longer built
914        by "configure", with the version identification directly included. There is
915        no longer a pcre.h.in file.
917        However, this change necessitated a change to the pcre-config script as
918        well. It is built from pcre-config.in, and one of the substitutions was the
919        release number. I have updated configure.ac so that ./configure now finds
920        the release number by grepping pcre.h.
922    26. Added the ability to run the tests under valgrind.
925    Version 6.4 05-Sep-05
926    ---------------------
928     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
929        "--" to be printed when multiple files were scanned, even when none of the
930        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
931        consider it to be a bug, and have restored the previous behaviour.
933     2. A couple of code tidies to get rid of compiler warnings.
935     3. The pcretest program used to cheat by referring to symbols in the library
936        whose names begin with _pcre_. These are internal symbols that are not
937        really supposed to be visible externally, and in some environments it is
938        possible to suppress them. The cheating is now confined to including
939        certain files from the library's source, which is a bit cleaner.
941     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
942        file's purpose clearer.
944     5. Reorganized pcre_ucp_findchar().
947  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
948  ---------------------  ---------------------

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