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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.2 01-May-07
5    ---------------------
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8        which is apparently normally available under Windows.
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11        to make them independent of the local environment's newline setting.
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
15     4. Some of the "internals" tests were previously cut out when the link size
16        was not 2, because the output contained actual offsets. The recent new
17        "Z" feature of pcretest means that these can be cut out, making the tests
18        usable with all link sizes.
20     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21        stack recursion. This gives a massive performance boost under BSD, but just
22        a small improvement under Linux. However, it saves one field in the frame
23        in all cases.
25     6. Added more features from the forthcoming Perl 5.10:
27        (a) (?-n) (where n is a string of digits) is a relative subroutine or
28            recursion call. It refers to the nth most recently opened parentheses.
30        (b) (?+n) is also a relative subroutine call; it refers to the nth next
31            to be opened parentheses.
33        (c) Conditions that refer to capturing parentheses can be specified
34            relatively, for example, (?(-2)... or (?(+3)...
36        (d) \K resets the start of the current match so that everything before
37            is not part of it.
39        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
41        (f) \g{name} is another synonym - part of Perl 5.10's unification of
42            reference syntax.
44     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
47     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
48        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
49        for detecting groups that can match an empty string.
52    Version 7.1 24-Apr-07
53    ---------------------
55     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
56        that is more "standard", making use of automake and other Autotools. There
57        is some re-arrangement of the files and adjustment of comments consequent
58        on this.
60     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
61        for recursive directory scanning broke on some systems because the files
62        are not scanned in any specific order and on different systems the order
63        was different. A call to "sort" has been inserted into RunGrepTest for the
64        approprate test as a short-term fix. In the longer term there may be an
65        alternative.
67     3. I had an email from Eric Raymond about problems translating some of PCRE's
68        man pages to HTML (despite the fact that I distribute HTML pages, some
69        people do their own conversions for various reasons). The problems
70        concerned the use of low-level troff macros .br and .in. I have therefore
71        removed all such uses from the man pages (some were redundant, some could
72        be replaced by .nf/.fi pairs). The 132html script that I use to generate
73        HTML has been updated to handle .nf/.fi and to complain if it encounters
74        .br or .in.
76     4. Updated comments in configure.ac that get placed in config.h.in and also
77        arranged for config.h to be included in the distribution, with the name
78        config.h.generic, for the benefit of those who have to compile without
79        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
81     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
82        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
83        makevp.bat for the current PCRE, using the additional files
84        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
86     6. A Windows user reported a minor discrepancy with test 2, which turned out
87        to be caused by a trailing space on an input line that had got lost in his
88        copy. The trailing space was an accident, so I've just removed it.
90     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
91        that is needed.
93     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
94        as "const" (a) because they are and (b) because it helps the PHP
95        maintainers who have recently made a script to detect big data structures
96        in the php code that should be moved to the .rodata section. I remembered
97        to update Builducptable as well, so it won't revert if ucptable.h is ever
98        re-created.
100     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
101        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
102        order to be able to cut out the UTF-8 tables in the latter when UTF-8
103        support is not required. This saves 1.5-2K of code, which is important in
104        some applications.
106        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
107        so as not to refer to the tables, even though these functions will never be
108        called when UTF-8 support is disabled. Otherwise there are problems with a
109        shared library.
111    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
113        (a) It was defining its arguments as char * instead of void *.
115        (b) It was assuming that all moves were upwards in memory; this was true
116            a long time ago when I wrote it, but is no longer the case.
118        The emulated memove() is provided for those environments that have neither
119        memmove() nor bcopy(). I didn't think anyone used it these days, but that
120        is clearly not the case, as these two bugs were recently reported.
122    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
123        and Detrail to create the HTML documentation, the .txt form of the man
124        pages, and it removes trailing spaces from listed files. It also creates
125        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
126        case, it wraps all the #defines with #ifndefs. This script should be run
127        before "make dist".
129    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
130        with Unicode property support.
132        (a) For a maximizing quantifier, if the two different cases of the
133            character were of different lengths in their UTF-8 codings (there are
134            some cases like this - I found 11), and the matching function had to
135            back up over a mixture of the two cases, it incorrectly assumed they
136            were both the same length.
138        (b) When PCRE was configured to use the heap rather than the stack for
139            recursion during matching, it was not correctly preserving the data for
140            the other case of a UTF-8 character when checking ahead for a match
141            while processing a minimizing repeat. If the check also involved
142            matching a wide character, but failed, corruption could cause an
143            erroneous result when trying to check for a repeat of the original
144            character.
146    13. Some tidying changes to the testing mechanism:
148        (a) The RunTest script now detects the internal link size and whether there
149            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
150            values substituted by "configure". (The RunGrepTest script already did
151            this for UTF-8.) The configure.ac script no longer substitutes the
152            relevant variables.
154        (b) The debugging options /B and /D in pcretest show the compiled bytecode
155            with length and offset values. This means that the output is different
156            for different internal link sizes. Test 2 is skipped for link sizes
157            other than 2 because of this, bypassing the problem. Unfortunately,
158            there was also a test in test 3 (the locale tests) that used /B and
159            failed for link sizes other than 2. Rather than cut the whole test out,
160            I have added a new /Z option to pcretest that replaces the length and
161            offset values with spaces. This is now used to make test 3 independent
162            of link size. (Test 2 will be tidied up later.)
164    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
165        segmentation fault instead of returning the appropriate error message.
167    15. In multiline mode when the newline sequence was set to "any", the pattern
168        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
169        This doesn't seem right; it now treats the CRLF combination as the line
170        ending, and so does not match in that case. It's only a pattern such as ^$
171        that would hit this one: something like ^ABC$ would have failed after \r
172        and then tried again after \r\n.
174    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
175        in an attempt to make files that differ only in their line terminators
176        compare equal. This works on Linux.
178    17. Under certain error circumstances pcregrep might try to free random memory
179        as it exited. This is now fixed, thanks to valgrind.
181    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
182        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
183        was because its rules for how to advance for /g after matching an empty
184        string at the end of a line did not allow for this case. They now check for
185        it specially.
187    20. pcretest is supposed to handle patterns and data of any length, by
188        extending its buffers when necessary. It was getting this wrong when the
189        buffer for a data line had to be extended.
191    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
192        CRLF as a newline sequence.
194    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
195        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
196        I have nevertheless tidied it up.
198    23. Added some casts to kill warnings from HP-UX ia64 compiler.
200    24. Added a man page for pcre-config.
203    Version 7.0 19-Dec-06
204    ---------------------
206     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
207        moving to gcc 4.1.1.
209     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
210        sys/time.h, which is documented as needed for this function. It doesn't
211        seem to matter on Linux, but it showed up on some releases of OS X.
213     3. It seems that there are systems where bytes whose values are greater than
214        127 match isprint() in the "C" locale. The "C" locale should be the
215        default when a C program starts up. In most systems, only ASCII printing
216        characters match isprint(). This difference caused the output from pcretest
217        to vary, making some of the tests fail. I have changed pcretest so that:
219        (a) When it is outputting text in the compiled version of a pattern, bytes
220            other than 32-126 are always shown as hex escapes.
222        (b) When it is outputting text that is a matched part of a subject string,
223            it does the same, unless a different locale has been set for the match
224            (using the /L modifier). In this case, it uses isprint() to decide.
226     4. Fixed a major bug that caused incorrect computation of the amount of memory
227        required for a compiled pattern when options that changed within the
228        pattern affected the logic of the preliminary scan that determines the
229        length. The relevant options are -x, and -i in UTF-8 mode. The result was
230        that the computed length was too small. The symptoms of this bug were
231        either the PCRE error "internal error: code overflow" from pcre_compile(),
232        or a glibc crash with a message such as "pcretest: free(): invalid next
233        size (fast)". Examples of patterns that provoked this bug (shown in
234        pcretest format) are:
236          /(?-x: )/x
237          /(?x)(?-x: \s*#\s*)/
238          /((?i)[\x{c0}])/8
239          /(?i:[\x{c0}])/8
241        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
242        is now done differently.
244     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
245        wrapper classes; (b) implement a new function in the C++ scanner that is
246        more efficient than the old way of doing things because it avoids levels of
247        recursion in the regex matching; (c) add a paragraph to the documentation
248        for the FullMatch() function.
250     6. The escape sequence \n was being treated as whatever was defined as
251        "newline". Not only was this contrary to the documentation, which states
252        that \n is character 10 (hex 0A), but it also went horribly wrong when
253        "newline" was defined as CRLF. This has been fixed.
255     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
256        was being set to -1 for the "end of line" case (supposedly a value that no
257        character can have). Though this value is never used (the check for end of
258        line is "zero bytes in current character"), it caused compiler complaints.
259        I've changed it to 0xffffffff.
261     8. In pcre_version.c, the version string was being built by a sequence of
262        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
263        string (as it is for production releases) called a macro with an empty
264        argument. The C standard says the result of this is undefined. The gcc
265        compiler treats it as an empty string (which was what was wanted) but it is
266        reported that Visual C gives an error. The source has been hacked around to
267        avoid this problem.
269     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
270        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
271        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
272        of them did).
274    10. Originally, pcretest opened its input and output without "b"; then I was
275        told that "b" was needed in some environments, so it was added for release
276        5.0 to both the input and output. (It makes no difference on Unix-like
277        systems.) Later I was told that it is wrong for the input on Windows. I've
278        now abstracted the modes into two macros, to make it easier to fiddle with
279        them, and removed "b" from the input mode under Windows.
281    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
283    12. Added -help and --help to pcretest as an official way of being reminded
284        of the options.
286    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
287        and pcrecpp.cc because they annoy compilers at high warning levels.
289    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
291    15. Fixed an occurrence of == in configure.ac that should have been = (shell
292        scripts are not C programs :-) and which was not noticed because it works
293        on Linux.
295    16. pcretest is supposed to handle any length of pattern and data line (as one
296        line or as a continued sequence of lines) by extending its input buffer if
297        necessary. This feature was broken for very long pattern lines, leading to
298        a string of junk being passed to pcre_compile() if the pattern was longer
299        than about 50K.
301    17. I have done a major re-factoring of the way pcre_compile() computes the
302        amount of memory needed for a compiled pattern. Previously, there was code
303        that made a preliminary scan of the pattern in order to do this. That was
304        OK when PCRE was new, but as the facilities have expanded, it has become
305        harder and harder to keep it in step with the real compile phase, and there
306        have been a number of bugs (see for example, 4 above). I have now found a
307        cunning way of running the real compile function in a "fake" mode that
308        enables it to compute how much memory it would need, while actually only
309        ever using a few hundred bytes of working memory and without too many
310        tests of the mode. This should make future maintenance and development
311        easier. A side effect of this work is that the limit of 200 on the nesting
312        depth of parentheses has been removed (though this was never a serious
313        limitation, I suspect). However, there is a downside: pcre_compile() now
314        runs more slowly than before (30% or more, depending on the pattern). I
315        hope this isn't a big issue. There is no effect on runtime performance.
317    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
318        newline (only possible for the last line of a file) and it was a
319        pattern that set a locale (followed by /Lsomething), pcretest crashed.
321    19. Added additional timing features to pcretest. (1) The -tm option now times
322        matching only, not compiling. (2) Both -t and -tm can be followed, as a
323        separate command line item, by a number that specifies the number of
324        repeats to use when timing. The default is 50000; this gives better
325        precision, but takes uncomfortably long for very large patterns.
327    20. Extended pcre_study() to be more clever in cases where a branch of a
328        subpattern has no definite first character. For example, (a*|b*)[cd] would
329        previously give no result from pcre_study(). Now it recognizes that the
330        first character must be a, b, c, or d.
332    21. There was an incorrect error "recursive call could loop indefinitely" if
333        a subpattern (or the entire pattern) that was being tested for matching an
334        empty string contained only one non-empty item after a nested subpattern.
335        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
336        incorrectly, because the \d was being skipped in the check.
338    22. The pcretest program now has a new pattern option /B and a command line
339        option -b, which is equivalent to adding /B to every pattern. This causes
340        it to show the compiled bytecode, without the additional information that
341        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
342        is the same as /B/I).
344    23. A new optimization is now able automatically to treat some sequences such
345        as a*b as a*+b. More specifically, if something simple (such as a character
346        or a simple class like \d) has an unlimited quantifier, and is followed by
347        something that cannot possibly match the quantified thing, the quantifier
348        is automatically "possessified".
350    24. A recursive reference to a subpattern whose number was greater than 39
351        went wrong under certain circumstances in UTF-8 mode. This bug could also
352        have affected the operation of pcre_study().
354    25. Realized that a little bit of performance could be had by replacing
355        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
357    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
359    27. Possessive quantifiers such as a++ were previously implemented by turning
360        them into atomic groups such as ($>a+). Now they have their own opcodes,
361        which improves performance. This includes the automatically created ones
362        from 23 above.
364    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
365        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
366        the first matched character to be a colon. This applied both to named and
367        numbered groups.
369    29. The ucpinternal.h header file was missing its idempotency #ifdef.
371    30. I was sent a "project" file called libpcre.a.dev which I understand makes
372        building PCRE on Windows easier, so I have included it in the distribution.
374    31. There is now a check in pcretest against a ridiculously large number being
375        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
376        loop, the loop is abandoned.
378    32. Forward references to subpatterns in conditions such as (?(2)...) where
379        subpattern 2 is defined later cause pcre_compile() to search forwards in
380        the pattern for the relevant set of parentheses. This search went wrong
381        when there were unescaped parentheses in a character class, parentheses
382        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
384    33. "Subroutine" calls and backreferences were previously restricted to
385        referencing subpatterns earlier in the regex. This restriction has now
386        been removed.
388    34. Added a number of extra features that are going to be in Perl 5.10. On the
389        whole, these are just syntactic alternatives for features that PCRE had
390        previously implemented using the Python syntax or my own invention. The
391        other formats are all retained for compatibility.
393        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
394            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
395            also .NET compatible.
397        (b) A recursion or subroutine call to a named group can now be defined as
398            (?&name) as well as (?P>name).
400        (c) A backreference to a named group can now be defined as \k<name> or
401            \k'name' as well as (?P=name). The new forms, as well as being in Perl
402            5.10, are also .NET compatible.
404        (d) A conditional reference to a named group can now use the syntax
405            (?(<name>) or (?('name') as well as (?(name).
407        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
408            groups (named and numbered) that are never evaluated inline, but can be
409            called as "subroutines" from elsewhere. In effect, the DEFINE condition
410            is always false. There may be only one alternative in such a group.
412        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
413            as the simple (?(R). The condition is true only if the most recent
414            recursion is that of the given number or name. It does not search out
415            through the entire recursion stack.
417        (g) The escape \gN or \g{N} has been added, where N is a positive or
418            negative number, specifying an absolute or relative reference.
420    35. Tidied to get rid of some further signed/unsigned compiler warnings and
421        some "unreachable code" warnings.
423    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
424        things, this adds five new scripts.
426    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
427        There were also incompatibilities regarding the handling of \Q..\E inside
428        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
429        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
431    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
432        matches an empty string, and forcibly breaks the loop. There were bugs in
433        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
434        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
435        separate and independent bugs (that affected different cases) have been
436        fixed.
438    39. Refactored the code to abolish the use of different opcodes for small
439        capturing bracket numbers. This is a tidy that I avoided doing when I
440        removed the limit on the number of capturing brackets for 3.5 back in 2001.
441        The new approach is not only tidier, it makes it possible to reduce the
442        memory needed to fix the previous bug (38).
444    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
445        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
446        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
447        mode.
449    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
450        report.
452    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
453        copy construction and assignment in the C++ wrapper.
455    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
456        couple of bugs that could have given wrong results in the "--newline=crlf"
457        case.
459    44. Added a number of casts and did some reorganization of signed/unsigned int
460        variables following suggestions from Dair Grant. Also renamed the variable
461        "this" as "item" because it is a C++ keyword.
463    45. Arranged for dftables to add
465          #include "pcre_internal.h"
467        to pcre_chartables.c because without it, gcc 4.x may remove the array
468        definition from the final binary if PCRE is built into a static library and
469        dead code stripping is activated.
471    46. For an unanchored pattern, if a match attempt fails at the start of a
472        newline sequence, and the newline setting is CRLF or ANY, and the next two
473        characters are CRLF, advance by two characters instead of one.
476    Version 6.7 04-Jul-06
477    ---------------------
479     1. In order to handle tests when input lines are enormously long, pcretest has
480        been re-factored so that it automatically extends its buffers when
481        necessary. The code is crude, but this _is_ just a test program. The
482        default size has been increased from 32K to 50K.
484     2. The code in pcre_study() was using the value of the re argument before
485        testing it for NULL. (Of course, in any sensible call of the function, it
486        won't be NULL.)
488     3. The memmove() emulation function in pcre_internal.h, which is used on
489        systems that lack both memmove() and bcopy() - that is, hardly ever -
490        was missing a "static" storage class specifier.
492     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
493        containing an extended class (one that cannot be represented by a bitmap
494        because it contains high-valued characters or Unicode property items, e.g.
495        [\pZ]). Almost always one would set UTF-8 mode when processing such a
496        pattern, but PCRE should not loop if you do not (it no longer does).
497        [Detail: two cases were found: (a) a repeated subpattern containing an
498        extended class; (b) a recursive reference to a subpattern that followed a
499        previous extended class. It wasn't skipping over the extended class
500        correctly when UTF-8 mode was not set.]
502     5. A negated single-character class was not being recognized as fixed-length
503        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
504        compile error "lookbehind assertion is not fixed length".
506     6. The RunPerlTest auxiliary script was showing an unexpected difference
507        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
508        write a Perl script that can interpret lines of an input file either as
509        byte characters or as UTF-8, which is what "perltest" was being required to
510        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
511        can't do is switch easily at run time between having the "use utf8;" pragma
512        or not. In the end, I fudged it by using the RunPerlTest script to insert
513        "use utf8;" explicitly for the UTF-8 tests.
515     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
516        the end of the subject string, contrary to the documentation and to what
517        Perl does. This was true of both matching functions. Now it matches only at
518        the start of the subject and immediately after *internal* newlines.
520     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
521        a pointer to an int instead of a pointer to an unsigned long int. This
522        caused problems on 64-bit systems.
524     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
525        instance of the 'standard' template library not being so standard".
527    10. There was no check on the number of named subpatterns nor the maximum
528        length of a subpattern name. The product of these values is used to compute
529        the size of the memory block for a compiled pattern. By supplying a very
530        long subpattern name and a large number of named subpatterns, the size
531        computation could be caused to overflow. This is now prevented by limiting
532        the length of names to 32 characters, and the number of named subpatterns
533        to 10,000.
535    11. Subpatterns that are repeated with specific counts have to be replicated in
536        the compiled pattern. The size of memory for this was computed from the
537        length of the subpattern and the repeat count. The latter is limited to
538        65535, but there was no limit on the former, meaning that integer overflow
539        could in principle occur. The compiled length of a repeated subpattern is
540        now limited to 30,000 bytes in order to prevent this.
542    12. Added the optional facility to have named substrings with the same name.
544    13. Added the ability to use a named substring as a condition, using the
545        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
546        are numbers (not recommended). Forward references are permitted.
548    14. Added forward references in named backreferences (if you see what I mean).
550    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
551        pattern could run off the end of the subject. For example, the pattern
552        "(?s)(.{1,5})"8 did this with the subject "ab".
554    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
555        PCRE_CASELESS was set when matching characters that were quantified with ?
556        or *.
558    17. A character class other than a single negated character that had a minimum
559        but no maximum quantifier - for example [ab]{6,} - was not handled
560        correctly by pce_dfa_exec(). It would match only one character.
562    18. A valid (though odd) pattern that looked like a POSIX character
563        class but used an invalid character after [ (for example [[,abc,]]) caused
564        pcre_compile() to give the error "Failed: internal error: code overflow" or
565        in some cases to crash with a glibc free() error. This could even happen if
566        the pattern terminated after [[ but there just happened to be a sequence of
567        letters, a binary zero, and a closing ] in the memory that followed.
569    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
570        over the years. Originally (before any Unicode support), just the bottom 8
571        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
572        output from "man perlunicode" includes this:
574          The regular expression compiler produces polymorphic opcodes.  That
575          is, the pattern adapts to the data and automatically switches to
576          the Unicode character scheme when presented with Unicode data--or
577          instead uses a traditional byte scheme when presented with byte
578          data.
580        Sadly, a wide octal escape does not cause a switch, and in a string with
581        no other multibyte characters, these octal escapes are treated as before.
582        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
583        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
584        Unicode string.
586        I have not perpetrated such confusion in PCRE. Up till now, it took just
587        the bottom 8 bits, as in old Perl. I have now made octal escapes with
588        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
589        translate to the appropriate multibyte character.
591    29. Applied some refactoring to reduce the number of warnings from Microsoft
592        and Borland compilers. This has included removing the fudge introduced
593        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
594        a warning about an unused variable.
596    21. PCRE has not included VT (character 0x0b) in the set of whitespace
597        characters since release 4.0, because Perl (from release 5.004) does not.
598        [Or at least, is documented not to: some releases seem to be in conflict
599        with the documentation.] However, when a pattern was studied with
600        pcre_study() and all its branches started with \s, PCRE still included VT
601        as a possible starting character. Of course, this did no harm; it just
602        caused an unnecessary match attempt.
604    22. Removed a now-redundant internal flag bit that recorded the fact that case
605        dependency changed within the pattern. This was once needed for "required
606        byte" processing, but is no longer used. This recovers a now-scarce options
607        bit. Also moved the least significant internal flag bit to the most-
608        significant bit of the word, which was not previously used (hangover from
609        the days when it was an int rather than a uint) to free up another bit for
610        the future.
612    23. Added support for CRLF line endings as well as CR and LF. As well as the
613        default being selectable at build time, it can now be changed at runtime
614        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
615        specify that it is scanning data with non-default line endings.
617    24. Changed the definition of CXXLINK to make it agree with the definition of
618        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
620    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
621        recursions. This makes a big different to stack usage for some patterns.
623    26. If a subpattern containing a named recursion or subroutine reference such
624        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
625        the space required for the compiled pattern went wrong and gave too small a
626        value. Depending on the environment, this could lead to "Failed: internal
627        error: code overflow at offset 49" or "glibc detected double free or
628        corruption" errors.
630    27. Applied patches from Google (a) to support the new newline modes and (b) to
631        advance over multibyte UTF-8 characters in GlobalReplace.
633    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
634        difference for some implementation of PCRE in some Windows version.
636    29. Added some extra testing facilities to pcretest:
638        \q<number>   in a data line sets the "match limit" value
639        \Q<number>   in a data line sets the "match recursion limt" value
640        -S <number>  sets the stack size, where <number> is in megabytes
642        The -S option isn't available for Windows.
645    Version 6.6 06-Feb-06
646    ---------------------
648     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
649        in pcreposix.h. I have copied the definition from pcre.h.
651     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
652        because pcre.h is no longer a built file.
654     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
655        not normally included in the compiled code.
658    Version 6.5 01-Feb-06
659    ---------------------
661     1. When using the partial match feature with pcre_dfa_exec(), it was not
662        anchoring the second and subsequent partial matches at the new starting
663        point. This could lead to incorrect results. For example, with the pattern
664        /1234/, partially matching against "123" and then "a4" gave a match.
666     2. Changes to pcregrep:
668        (a) All non-match returns from pcre_exec() were being treated as failures
669            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
670            error message is output. Some extra information is given for the
671            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
672            probably the only errors that are likely to be caused by users (by
673            specifying a regex that has nested indefinite repeats, for instance).
674            If there are more than 20 of these errors, pcregrep is abandoned.
676        (b) A binary zero was treated as data while matching, but terminated the
677            output line if it was written out. This has been fixed: binary zeroes
678            are now no different to any other data bytes.
680        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
681            used to set a locale for matching. The --locale=xxxx long option has
682            been added (no short equivalent) to specify a locale explicitly on the
683            pcregrep command, overriding the environment variables.
685        (d) When -B was used with -n, some line numbers in the output were one less
686            than they should have been.
688        (e) Added the -o (--only-matching) option.
690        (f) If -A or -C was used with -c (count only), some lines of context were
691            accidentally printed for the final match.
693        (g) Added the -H (--with-filename) option.
695        (h) The combination of options -rh failed to suppress file names for files
696            that were found from directory arguments.
698        (i) Added the -D (--devices) and -d (--directories) options.
700        (j) Added the -F (--fixed-strings) option.
702        (k) Allow "-" to be used as a file name for -f as well as for a data file.
704        (l) Added the --colo(u)r option.
706        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
707            is not present by default.
709     3. A nasty bug was discovered in the handling of recursive patterns, that is,
710        items such as (?R) or (?1), when the recursion could match a number of
711        alternatives. If it matched one of the alternatives, but subsequently,
712        outside the recursion, there was a failure, the code tried to back up into
713        the recursion. However, because of the way PCRE is implemented, this is not
714        possible, and the result was an incorrect result from the match.
716        In order to prevent this happening, the specification of recursion has
717        been changed so that all such subpatterns are automatically treated as
718        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
720     4. I had overlooked the fact that, in some locales, there are characters for
721        which isalpha() is true but neither isupper() nor islower() are true. In
722        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
723        and ordfeminine) are like this. This affected the treatment of \w and \W
724        when they appeared in character classes, but not when they appeared outside
725        a character class. The bit map for "word" characters is now created
726        separately from the results of isalnum() instead of just taking it from the
727        upper, lower, and digit maps. (Plus the underscore character, of course.)
729     5. The above bug also affected the handling of POSIX character classes such as
730        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
731        permanent tables. Instead, the bit maps for such a class were previously
732        created as the appropriate unions of the upper, lower, and digit bitmaps.
733        Now they are created by subtraction from the [[:word:]] class, which has
734        its own bitmap.
736     6. The [[:blank:]] character class matches horizontal, but not vertical space.
737        It is created by subtracting the vertical space characters (\x09, \x0a,
738        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
739        subtraction was done in the overall bitmap for a character class, meaning
740        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
741        be recognized. This bug has been fixed.
743     7. Patches from the folks at Google:
745          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
746          real life, but is still worth protecting against".
748          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
749          regular expressions".
751          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
752          have it.
754          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
755          "configure" and the latter not, in order to fix a problem somebody had
756          with compiling the Arg class on HP-UX.
758          (e) Improve the error-handling of the C++ wrapper a little bit.
760          (f) New tests for checking recursion limiting.
762     8. The pcre_memmove() function, which is used only if the environment does not
763        have a standard memmove() function (and is therefore rarely compiled),
764        contained two bugs: (a) use of int instead of size_t, and (b) it was not
765        returning a result (though PCRE never actually uses the result).
767     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
768        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
769        returned instead of calling malloc() with an overflowing number that would
770        most likely cause subsequent chaos.
772    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
774    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
775        with this option is matched, the nmatch and pmatch options of regexec() are
776        ignored.
778    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
779        provided in case anyone wants to the the POSIX interface with UTF-8
780        strings.
782    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
783        C++ linking (needed for some HP-UX environments).
785    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
786        (unused parameter) and in the pcre_printint() function (omitted "default"
787        switch label when the default is to do nothing).
789    15. Added some code to make it possible, when PCRE is compiled as a C++
790        library, to replace subject pointers for pcre_exec() with a smart pointer
791        class, thus making it possible to process discontinuous strings.
793    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
794        much the same function. They were added by different people who were trying
795        to make PCRE easy to compile on non-Unix systems. It has been suggested
796        that PCRE_EXPORT be abolished now that there is more automatic apparatus
797        for compiling on Windows systems. I have therefore replaced it with
798        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
799        defaults to "extern" for C or "extern C" for C++, which works fine on
800        Unix-like systems. It is now possible to override the value of PCRE_DATA_
801        SCOPE with something explicit in config.h. In addition:
803        (a) pcreposix.h still had just "extern" instead of either of these macros;
804            I have replaced it with PCRE_DATA_SCOPE.
806        (b) Functions such as _pcre_xclass(), which are internal to the library,
807            but external in the C sense, all had PCRE_EXPORT in their definitions.
808            This is apparently wrong for the Windows case, so I have removed it.
809            (It makes no difference on Unix-like systems.)
811    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
812        of recursive calls to match(). This is different to MATCH_LIMIT because
813        that limits the total number of calls to match(), not all of which increase
814        the depth of recursion. Limiting the recursion depth limits the amount of
815        stack (or heap if NO_RECURSE is set) that is used. The default can be set
816        when PCRE is compiled, and changed at run time. A patch from Google adds
817        this functionality to the C++ interface.
819    18. Changes to the handling of Unicode character properties:
821        (a) Updated the table to Unicode 4.1.0.
823        (b) Recognize characters that are not in the table as "Cn" (undefined).
825        (c) I revised the way the table is implemented to a much improved format
826            which includes recognition of ranges. It now supports the ranges that
827            are defined in UnicodeData.txt, and it also amalgamates other
828            characters into ranges. This has reduced the number of entries in the
829            table from around 16,000 to around 3,000, thus reducing its size
830            considerably. I realized I did not need to use a tree structure after
831            all - a binary chop search is just as efficient. Having reduced the
832            number of entries, I extended their size from 6 bytes to 8 bytes to
833            allow for more data.
835        (d) Added support for Unicode script names via properties such as \p{Han}.
837    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
838        matching that character.
840    20. When matching a repeated Unicode property with a minimum greater than zero,
841        (for example \pL{2,}), PCRE could look past the end of the subject if it
842        reached it while seeking the minimum number of characters. This could
843        happen only if some of the characters were more than one byte long, because
844        there is a check for at least the minimum number of bytes.
846    21. Refactored the implementation of \p and \P so as to be more general, to
847        allow for more different types of property in future. This has changed the
848        compiled form incompatibly. Anybody with saved compiled patterns that use
849        \p or \P will have to recompile them.
851    22. Added "Any" and "L&" to the supported property types.
853    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
854        but give a compile time error if the value is greater than 0xff.
856    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
857        accidentally not being installed or uninstalled.
859    25. The pcre.h file was built from pcre.h.in, but the only changes that were
860        made were to insert the current release number. This seemed silly, because
861        it made things harder for people building PCRE on systems that don't run
862        "configure". I have turned pcre.h into a distributed file, no longer built
863        by "configure", with the version identification directly included. There is
864        no longer a pcre.h.in file.
866        However, this change necessitated a change to the pcre-config script as
867        well. It is built from pcre-config.in, and one of the substitutions was the
868        release number. I have updated configure.ac so that ./configure now finds
869        the release number by grepping pcre.h.
871    26. Added the ability to run the tests under valgrind.
874    Version 6.4 05-Sep-05
875    ---------------------
877     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
878        "--" to be printed when multiple files were scanned, even when none of the
879        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
880        consider it to be a bug, and have restored the previous behaviour.
882     2. A couple of code tidies to get rid of compiler warnings.
884     3. The pcretest program used to cheat by referring to symbols in the library
885        whose names begin with _pcre_. These are internal symbols that are not
886        really supposed to be visible externally, and in some environments it is
887        possible to suppress them. The cheating is now confined to including
888        certain files from the library's source, which is a bit cleaner.
890     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
891        file's purpose clearer.
893     5. Reorganized pcre_ucp_findchar().
896  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
897  ---------------------  ---------------------

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