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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.
40    Version 7.1 24-Apr-07
41    ---------------------
43     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
44        that is more "standard", making use of automake and other Autotools. There
45        is some re-arrangement of the files and adjustment of comments consequent
46        on this.
48     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
49        for recursive directory scanning broke on some systems because the files
50        are not scanned in any specific order and on different systems the order
51        was different. A call to "sort" has been inserted into RunGrepTest for the
52        approprate test as a short-term fix. In the longer term there may be an
53        alternative.
55     3. I had an email from Eric Raymond about problems translating some of PCRE's
56        man pages to HTML (despite the fact that I distribute HTML pages, some
57        people do their own conversions for various reasons). The problems
58        concerned the use of low-level troff macros .br and .in. I have therefore
59        removed all such uses from the man pages (some were redundant, some could
60        be replaced by .nf/.fi pairs). The 132html script that I use to generate
61        HTML has been updated to handle .nf/.fi and to complain if it encounters
62        .br or .in.
64     4. Updated comments in configure.ac that get placed in config.h.in and also
65        arranged for config.h to be included in the distribution, with the name
66        config.h.generic, for the benefit of those who have to compile without
67        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
69     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
70        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
71        makevp.bat for the current PCRE, using the additional files
72        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
74     6. A Windows user reported a minor discrepancy with test 2, which turned out
75        to be caused by a trailing space on an input line that had got lost in his
76        copy. The trailing space was an accident, so I've just removed it.
78     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
79        that is needed.
81     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
82        as "const" (a) because they are and (b) because it helps the PHP
83        maintainers who have recently made a script to detect big data structures
84        in the php code that should be moved to the .rodata section. I remembered
85        to update Builducptable as well, so it won't revert if ucptable.h is ever
86        re-created.
88     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
89        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
90        order to be able to cut out the UTF-8 tables in the latter when UTF-8
91        support is not required. This saves 1.5-2K of code, which is important in
92        some applications.
94        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
95        so as not to refer to the tables, even though these functions will never be
96        called when UTF-8 support is disabled. Otherwise there are problems with a
97        shared library.
99    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
101        (a) It was defining its arguments as char * instead of void *.
103        (b) It was assuming that all moves were upwards in memory; this was true
104            a long time ago when I wrote it, but is no longer the case.
106        The emulated memove() is provided for those environments that have neither
107        memmove() nor bcopy(). I didn't think anyone used it these days, but that
108        is clearly not the case, as these two bugs were recently reported.
110    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
111        and Detrail to create the HTML documentation, the .txt form of the man
112        pages, and it removes trailing spaces from listed files. It also creates
113        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
114        case, it wraps all the #defines with #ifndefs. This script should be run
115        before "make dist".
117    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
118        with Unicode property support.
120        (a) For a maximizing quantifier, if the two different cases of the
121            character were of different lengths in their UTF-8 codings (there are
122            some cases like this - I found 11), and the matching function had to
123            back up over a mixture of the two cases, it incorrectly assumed they
124            were both the same length.
126        (b) When PCRE was configured to use the heap rather than the stack for
127            recursion during matching, it was not correctly preserving the data for
128            the other case of a UTF-8 character when checking ahead for a match
129            while processing a minimizing repeat. If the check also involved
130            matching a wide character, but failed, corruption could cause an
131            erroneous result when trying to check for a repeat of the original
132            character.
134    13. Some tidying changes to the testing mechanism:
136        (a) The RunTest script now detects the internal link size and whether there
137            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
138            values substituted by "configure". (The RunGrepTest script already did
139            this for UTF-8.) The configure.ac script no longer substitutes the
140            relevant variables.
142        (b) The debugging options /B and /D in pcretest show the compiled bytecode
143            with length and offset values. This means that the output is different
144            for different internal link sizes. Test 2 is skipped for link sizes
145            other than 2 because of this, bypassing the problem. Unfortunately,
146            there was also a test in test 3 (the locale tests) that used /B and
147            failed for link sizes other than 2. Rather than cut the whole test out,
148            I have added a new /Z option to pcretest that replaces the length and
149            offset values with spaces. This is now used to make test 3 independent
150            of link size. (Test 2 will be tidied up later.)
152    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
153        segmentation fault instead of returning the appropriate error message.
155    15. In multiline mode when the newline sequence was set to "any", the pattern
156        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
157        This doesn't seem right; it now treats the CRLF combination as the line
158        ending, and so does not match in that case. It's only a pattern such as ^$
159        that would hit this one: something like ^ABC$ would have failed after \r
160        and then tried again after \r\n.
162    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
163        in an attempt to make files that differ only in their line terminators
164        compare equal. This works on Linux.
166    17. Under certain error circumstances pcregrep might try to free random memory
167        as it exited. This is now fixed, thanks to valgrind.
169    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
170        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
171        was because its rules for how to advance for /g after matching an empty
172        string at the end of a line did not allow for this case. They now check for
173        it specially.
175    20. pcretest is supposed to handle patterns and data of any length, by
176        extending its buffers when necessary. It was getting this wrong when the
177        buffer for a data line had to be extended.
179    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
180        CRLF as a newline sequence.
182    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
183        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
184        I have nevertheless tidied it up.
186    23. Added some casts to kill warnings from HP-UX ia64 compiler.
188    24. Added a man page for pcre-config.
191    Version 7.0 19-Dec-06
192    ---------------------
194     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
195        moving to gcc 4.1.1.
197     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
198        sys/time.h, which is documented as needed for this function. It doesn't
199        seem to matter on Linux, but it showed up on some releases of OS X.
201     3. It seems that there are systems where bytes whose values are greater than
202        127 match isprint() in the "C" locale. The "C" locale should be the
203        default when a C program starts up. In most systems, only ASCII printing
204        characters match isprint(). This difference caused the output from pcretest
205        to vary, making some of the tests fail. I have changed pcretest so that:
207        (a) When it is outputting text in the compiled version of a pattern, bytes
208            other than 32-126 are always shown as hex escapes.
210        (b) When it is outputting text that is a matched part of a subject string,
211            it does the same, unless a different locale has been set for the match
212            (using the /L modifier). In this case, it uses isprint() to decide.
214     4. Fixed a major bug that caused incorrect computation of the amount of memory
215        required for a compiled pattern when options that changed within the
216        pattern affected the logic of the preliminary scan that determines the
217        length. The relevant options are -x, and -i in UTF-8 mode. The result was
218        that the computed length was too small. The symptoms of this bug were
219        either the PCRE error "internal error: code overflow" from pcre_compile(),
220        or a glibc crash with a message such as "pcretest: free(): invalid next
221        size (fast)". Examples of patterns that provoked this bug (shown in
222        pcretest format) are:
224          /(?-x: )/x
225          /(?x)(?-x: \s*#\s*)/
226          /((?i)[\x{c0}])/8
227          /(?i:[\x{c0}])/8
229        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
230        is now done differently.
232     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
233        wrapper classes; (b) implement a new function in the C++ scanner that is
234        more efficient than the old way of doing things because it avoids levels of
235        recursion in the regex matching; (c) add a paragraph to the documentation
236        for the FullMatch() function.
238     6. The escape sequence \n was being treated as whatever was defined as
239        "newline". Not only was this contrary to the documentation, which states
240        that \n is character 10 (hex 0A), but it also went horribly wrong when
241        "newline" was defined as CRLF. This has been fixed.
243     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
244        was being set to -1 for the "end of line" case (supposedly a value that no
245        character can have). Though this value is never used (the check for end of
246        line is "zero bytes in current character"), it caused compiler complaints.
247        I've changed it to 0xffffffff.
249     8. In pcre_version.c, the version string was being built by a sequence of
250        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
251        string (as it is for production releases) called a macro with an empty
252        argument. The C standard says the result of this is undefined. The gcc
253        compiler treats it as an empty string (which was what was wanted) but it is
254        reported that Visual C gives an error. The source has been hacked around to
255        avoid this problem.
257     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
258        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
259        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
260        of them did).
262    10. Originally, pcretest opened its input and output without "b"; then I was
263        told that "b" was needed in some environments, so it was added for release
264        5.0 to both the input and output. (It makes no difference on Unix-like
265        systems.) Later I was told that it is wrong for the input on Windows. I've
266        now abstracted the modes into two macros, to make it easier to fiddle with
267        them, and removed "b" from the input mode under Windows.
269    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
271    12. Added -help and --help to pcretest as an official way of being reminded
272        of the options.
274    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
275        and pcrecpp.cc because they annoy compilers at high warning levels.
277    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
279    15. Fixed an occurrence of == in configure.ac that should have been = (shell
280        scripts are not C programs :-) and which was not noticed because it works
281        on Linux.
283    16. pcretest is supposed to handle any length of pattern and data line (as one
284        line or as a continued sequence of lines) by extending its input buffer if
285        necessary. This feature was broken for very long pattern lines, leading to
286        a string of junk being passed to pcre_compile() if the pattern was longer
287        than about 50K.
289    17. I have done a major re-factoring of the way pcre_compile() computes the
290        amount of memory needed for a compiled pattern. Previously, there was code
291        that made a preliminary scan of the pattern in order to do this. That was
292        OK when PCRE was new, but as the facilities have expanded, it has become
293        harder and harder to keep it in step with the real compile phase, and there
294        have been a number of bugs (see for example, 4 above). I have now found a
295        cunning way of running the real compile function in a "fake" mode that
296        enables it to compute how much memory it would need, while actually only
297        ever using a few hundred bytes of working memory and without too many
298        tests of the mode. This should make future maintenance and development
299        easier. A side effect of this work is that the limit of 200 on the nesting
300        depth of parentheses has been removed (though this was never a serious
301        limitation, I suspect). However, there is a downside: pcre_compile() now
302        runs more slowly than before (30% or more, depending on the pattern). I
303        hope this isn't a big issue. There is no effect on runtime performance.
305    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
306        newline (only possible for the last line of a file) and it was a
307        pattern that set a locale (followed by /Lsomething), pcretest crashed.
309    19. Added additional timing features to pcretest. (1) The -tm option now times
310        matching only, not compiling. (2) Both -t and -tm can be followed, as a
311        separate command line item, by a number that specifies the number of
312        repeats to use when timing. The default is 50000; this gives better
313        precision, but takes uncomfortably long for very large patterns.
315    20. Extended pcre_study() to be more clever in cases where a branch of a
316        subpattern has no definite first character. For example, (a*|b*)[cd] would
317        previously give no result from pcre_study(). Now it recognizes that the
318        first character must be a, b, c, or d.
320    21. There was an incorrect error "recursive call could loop indefinitely" if
321        a subpattern (or the entire pattern) that was being tested for matching an
322        empty string contained only one non-empty item after a nested subpattern.
323        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
324        incorrectly, because the \d was being skipped in the check.
326    22. The pcretest program now has a new pattern option /B and a command line
327        option -b, which is equivalent to adding /B to every pattern. This causes
328        it to show the compiled bytecode, without the additional information that
329        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
330        is the same as /B/I).
332    23. A new optimization is now able automatically to treat some sequences such
333        as a*b as a*+b. More specifically, if something simple (such as a character
334        or a simple class like \d) has an unlimited quantifier, and is followed by
335        something that cannot possibly match the quantified thing, the quantifier
336        is automatically "possessified".
338    24. A recursive reference to a subpattern whose number was greater than 39
339        went wrong under certain circumstances in UTF-8 mode. This bug could also
340        have affected the operation of pcre_study().
342    25. Realized that a little bit of performance could be had by replacing
343        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
345    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
347    27. Possessive quantifiers such as a++ were previously implemented by turning
348        them into atomic groups such as ($>a+). Now they have their own opcodes,
349        which improves performance. This includes the automatically created ones
350        from 23 above.
352    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
353        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
354        the first matched character to be a colon. This applied both to named and
355        numbered groups.
357    29. The ucpinternal.h header file was missing its idempotency #ifdef.
359    30. I was sent a "project" file called libpcre.a.dev which I understand makes
360        building PCRE on Windows easier, so I have included it in the distribution.
362    31. There is now a check in pcretest against a ridiculously large number being
363        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
364        loop, the loop is abandoned.
366    32. Forward references to subpatterns in conditions such as (?(2)...) where
367        subpattern 2 is defined later cause pcre_compile() to search forwards in
368        the pattern for the relevant set of parentheses. This search went wrong
369        when there were unescaped parentheses in a character class, parentheses
370        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
372    33. "Subroutine" calls and backreferences were previously restricted to
373        referencing subpatterns earlier in the regex. This restriction has now
374        been removed.
376    34. Added a number of extra features that are going to be in Perl 5.10. On the
377        whole, these are just syntactic alternatives for features that PCRE had
378        previously implemented using the Python syntax or my own invention. The
379        other formats are all retained for compatibility.
381        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
382            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
383            also .NET compatible.
385        (b) A recursion or subroutine call to a named group can now be defined as
386            (?&name) as well as (?P>name).
388        (c) A backreference to a named group can now be defined as \k<name> or
389            \k'name' as well as (?P=name). The new forms, as well as being in Perl
390            5.10, are also .NET compatible.
392        (d) A conditional reference to a named group can now use the syntax
393            (?(<name>) or (?('name') as well as (?(name).
395        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
396            groups (named and numbered) that are never evaluated inline, but can be
397            called as "subroutines" from elsewhere. In effect, the DEFINE condition
398            is always false. There may be only one alternative in such a group.
400        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
401            as the simple (?(R). The condition is true only if the most recent
402            recursion is that of the given number or name. It does not search out
403            through the entire recursion stack.
405        (g) The escape \gN or \g{N} has been added, where N is a positive or
406            negative number, specifying an absolute or relative reference.
408    35. Tidied to get rid of some further signed/unsigned compiler warnings and
409        some "unreachable code" warnings.
411    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
412        things, this adds five new scripts.
414    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
415        There were also incompatibilities regarding the handling of \Q..\E inside
416        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
417        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
419    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
420        matches an empty string, and forcibly breaks the loop. There were bugs in
421        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
422        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
423        separate and independent bugs (that affected different cases) have been
424        fixed.
426    39. Refactored the code to abolish the use of different opcodes for small
427        capturing bracket numbers. This is a tidy that I avoided doing when I
428        removed the limit on the number of capturing brackets for 3.5 back in 2001.
429        The new approach is not only tidier, it makes it possible to reduce the
430        memory needed to fix the previous bug (38).
432    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
433        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
434        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
435        mode.
437    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
438        report.
440    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
441        copy construction and assignment in the C++ wrapper.
443    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
444        couple of bugs that could have given wrong results in the "--newline=crlf"
445        case.
447    44. Added a number of casts and did some reorganization of signed/unsigned int
448        variables following suggestions from Dair Grant. Also renamed the variable
449        "this" as "item" because it is a C++ keyword.
451    45. Arranged for dftables to add
453          #include "pcre_internal.h"
455        to pcre_chartables.c because without it, gcc 4.x may remove the array
456        definition from the final binary if PCRE is built into a static library and
457        dead code stripping is activated.
459    46. For an unanchored pattern, if a match attempt fails at the start of a
460        newline sequence, and the newline setting is CRLF or ANY, and the next two
461        characters are CRLF, advance by two characters instead of one.
464    Version 6.7 04-Jul-06
465    ---------------------
467     1. In order to handle tests when input lines are enormously long, pcretest has
468        been re-factored so that it automatically extends its buffers when
469        necessary. The code is crude, but this _is_ just a test program. The
470        default size has been increased from 32K to 50K.
472     2. The code in pcre_study() was using the value of the re argument before
473        testing it for NULL. (Of course, in any sensible call of the function, it
474        won't be NULL.)
476     3. The memmove() emulation function in pcre_internal.h, which is used on
477        systems that lack both memmove() and bcopy() - that is, hardly ever -
478        was missing a "static" storage class specifier.
480     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
481        containing an extended class (one that cannot be represented by a bitmap
482        because it contains high-valued characters or Unicode property items, e.g.
483        [\pZ]). Almost always one would set UTF-8 mode when processing such a
484        pattern, but PCRE should not loop if you do not (it no longer does).
485        [Detail: two cases were found: (a) a repeated subpattern containing an
486        extended class; (b) a recursive reference to a subpattern that followed a
487        previous extended class. It wasn't skipping over the extended class
488        correctly when UTF-8 mode was not set.]
490     5. A negated single-character class was not being recognized as fixed-length
491        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
492        compile error "lookbehind assertion is not fixed length".
494     6. The RunPerlTest auxiliary script was showing an unexpected difference
495        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
496        write a Perl script that can interpret lines of an input file either as
497        byte characters or as UTF-8, which is what "perltest" was being required to
498        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
499        can't do is switch easily at run time between having the "use utf8;" pragma
500        or not. In the end, I fudged it by using the RunPerlTest script to insert
501        "use utf8;" explicitly for the UTF-8 tests.
503     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
504        the end of the subject string, contrary to the documentation and to what
505        Perl does. This was true of both matching functions. Now it matches only at
506        the start of the subject and immediately after *internal* newlines.
508     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
509        a pointer to an int instead of a pointer to an unsigned long int. This
510        caused problems on 64-bit systems.
512     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
513        instance of the 'standard' template library not being so standard".
515    10. There was no check on the number of named subpatterns nor the maximum
516        length of a subpattern name. The product of these values is used to compute
517        the size of the memory block for a compiled pattern. By supplying a very
518        long subpattern name and a large number of named subpatterns, the size
519        computation could be caused to overflow. This is now prevented by limiting
520        the length of names to 32 characters, and the number of named subpatterns
521        to 10,000.
523    11. Subpatterns that are repeated with specific counts have to be replicated in
524        the compiled pattern. The size of memory for this was computed from the
525        length of the subpattern and the repeat count. The latter is limited to
526        65535, but there was no limit on the former, meaning that integer overflow
527        could in principle occur. The compiled length of a repeated subpattern is
528        now limited to 30,000 bytes in order to prevent this.
530    12. Added the optional facility to have named substrings with the same name.
532    13. Added the ability to use a named substring as a condition, using the
533        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
534        are numbers (not recommended). Forward references are permitted.
536    14. Added forward references in named backreferences (if you see what I mean).
538    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
539        pattern could run off the end of the subject. For example, the pattern
540        "(?s)(.{1,5})"8 did this with the subject "ab".
542    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
543        PCRE_CASELESS was set when matching characters that were quantified with ?
544        or *.
546    17. A character class other than a single negated character that had a minimum
547        but no maximum quantifier - for example [ab]{6,} - was not handled
548        correctly by pce_dfa_exec(). It would match only one character.
550    18. A valid (though odd) pattern that looked like a POSIX character
551        class but used an invalid character after [ (for example [[,abc,]]) caused
552        pcre_compile() to give the error "Failed: internal error: code overflow" or
553        in some cases to crash with a glibc free() error. This could even happen if
554        the pattern terminated after [[ but there just happened to be a sequence of
555        letters, a binary zero, and a closing ] in the memory that followed.
557    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
558        over the years. Originally (before any Unicode support), just the bottom 8
559        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
560        output from "man perlunicode" includes this:
562          The regular expression compiler produces polymorphic opcodes.  That
563          is, the pattern adapts to the data and automatically switches to
564          the Unicode character scheme when presented with Unicode data--or
565          instead uses a traditional byte scheme when presented with byte
566          data.
568        Sadly, a wide octal escape does not cause a switch, and in a string with
569        no other multibyte characters, these octal escapes are treated as before.
570        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
571        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
572        Unicode string.
574        I have not perpetrated such confusion in PCRE. Up till now, it took just
575        the bottom 8 bits, as in old Perl. I have now made octal escapes with
576        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
577        translate to the appropriate multibyte character.
579    29. Applied some refactoring to reduce the number of warnings from Microsoft
580        and Borland compilers. This has included removing the fudge introduced
581        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
582        a warning about an unused variable.
584    21. PCRE has not included VT (character 0x0b) in the set of whitespace
585        characters since release 4.0, because Perl (from release 5.004) does not.
586        [Or at least, is documented not to: some releases seem to be in conflict
587        with the documentation.] However, when a pattern was studied with
588        pcre_study() and all its branches started with \s, PCRE still included VT
589        as a possible starting character. Of course, this did no harm; it just
590        caused an unnecessary match attempt.
592    22. Removed a now-redundant internal flag bit that recorded the fact that case
593        dependency changed within the pattern. This was once needed for "required
594        byte" processing, but is no longer used. This recovers a now-scarce options
595        bit. Also moved the least significant internal flag bit to the most-
596        significant bit of the word, which was not previously used (hangover from
597        the days when it was an int rather than a uint) to free up another bit for
598        the future.
600    23. Added support for CRLF line endings as well as CR and LF. As well as the
601        default being selectable at build time, it can now be changed at runtime
602        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
603        specify that it is scanning data with non-default line endings.
605    24. Changed the definition of CXXLINK to make it agree with the definition of
606        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
608    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
609        recursions. This makes a big different to stack usage for some patterns.
611    26. If a subpattern containing a named recursion or subroutine reference such
612        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
613        the space required for the compiled pattern went wrong and gave too small a
614        value. Depending on the environment, this could lead to "Failed: internal
615        error: code overflow at offset 49" or "glibc detected double free or
616        corruption" errors.
618    27. Applied patches from Google (a) to support the new newline modes and (b) to
619        advance over multibyte UTF-8 characters in GlobalReplace.
621    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
622        difference for some implementation of PCRE in some Windows version.
624    29. Added some extra testing facilities to pcretest:
626        \q<number>   in a data line sets the "match limit" value
627        \Q<number>   in a data line sets the "match recursion limt" value
628        -S <number>  sets the stack size, where <number> is in megabytes
630        The -S option isn't available for Windows.
633    Version 6.6 06-Feb-06
634    ---------------------
636     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
637        in pcreposix.h. I have copied the definition from pcre.h.
639     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
640        because pcre.h is no longer a built file.
642     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
643        not normally included in the compiled code.
646    Version 6.5 01-Feb-06
647    ---------------------
649     1. When using the partial match feature with pcre_dfa_exec(), it was not
650        anchoring the second and subsequent partial matches at the new starting
651        point. This could lead to incorrect results. For example, with the pattern
652        /1234/, partially matching against "123" and then "a4" gave a match.
654     2. Changes to pcregrep:
656        (a) All non-match returns from pcre_exec() were being treated as failures
657            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
658            error message is output. Some extra information is given for the
659            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
660            probably the only errors that are likely to be caused by users (by
661            specifying a regex that has nested indefinite repeats, for instance).
662            If there are more than 20 of these errors, pcregrep is abandoned.
664        (b) A binary zero was treated as data while matching, but terminated the
665            output line if it was written out. This has been fixed: binary zeroes
666            are now no different to any other data bytes.
668        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
669            used to set a locale for matching. The --locale=xxxx long option has
670            been added (no short equivalent) to specify a locale explicitly on the
671            pcregrep command, overriding the environment variables.
673        (d) When -B was used with -n, some line numbers in the output were one less
674            than they should have been.
676        (e) Added the -o (--only-matching) option.
678        (f) If -A or -C was used with -c (count only), some lines of context were
679            accidentally printed for the final match.
681        (g) Added the -H (--with-filename) option.
683        (h) The combination of options -rh failed to suppress file names for files
684            that were found from directory arguments.
686        (i) Added the -D (--devices) and -d (--directories) options.
688        (j) Added the -F (--fixed-strings) option.
690        (k) Allow "-" to be used as a file name for -f as well as for a data file.
692        (l) Added the --colo(u)r option.
694        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
695            is not present by default.
697     3. A nasty bug was discovered in the handling of recursive patterns, that is,
698        items such as (?R) or (?1), when the recursion could match a number of
699        alternatives. If it matched one of the alternatives, but subsequently,
700        outside the recursion, there was a failure, the code tried to back up into
701        the recursion. However, because of the way PCRE is implemented, this is not
702        possible, and the result was an incorrect result from the match.
704        In order to prevent this happening, the specification of recursion has
705        been changed so that all such subpatterns are automatically treated as
706        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
708     4. I had overlooked the fact that, in some locales, there are characters for
709        which isalpha() is true but neither isupper() nor islower() are true. In
710        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
711        and ordfeminine) are like this. This affected the treatment of \w and \W
712        when they appeared in character classes, but not when they appeared outside
713        a character class. The bit map for "word" characters is now created
714        separately from the results of isalnum() instead of just taking it from the
715        upper, lower, and digit maps. (Plus the underscore character, of course.)
717     5. The above bug also affected the handling of POSIX character classes such as
718        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
719        permanent tables. Instead, the bit maps for such a class were previously
720        created as the appropriate unions of the upper, lower, and digit bitmaps.
721        Now they are created by subtraction from the [[:word:]] class, which has
722        its own bitmap.
724     6. The [[:blank:]] character class matches horizontal, but not vertical space.
725        It is created by subtracting the vertical space characters (\x09, \x0a,
726        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
727        subtraction was done in the overall bitmap for a character class, meaning
728        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
729        be recognized. This bug has been fixed.
731     7. Patches from the folks at Google:
733          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
734          real life, but is still worth protecting against".
736          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
737          regular expressions".
739          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
740          have it.
742          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
743          "configure" and the latter not, in order to fix a problem somebody had
744          with compiling the Arg class on HP-UX.
746          (e) Improve the error-handling of the C++ wrapper a little bit.
748          (f) New tests for checking recursion limiting.
750     8. The pcre_memmove() function, which is used only if the environment does not
751        have a standard memmove() function (and is therefore rarely compiled),
752        contained two bugs: (a) use of int instead of size_t, and (b) it was not
753        returning a result (though PCRE never actually uses the result).
755     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
756        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
757        returned instead of calling malloc() with an overflowing number that would
758        most likely cause subsequent chaos.
760    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
762    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
763        with this option is matched, the nmatch and pmatch options of regexec() are
764        ignored.
766    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
767        provided in case anyone wants to the the POSIX interface with UTF-8
768        strings.
770    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
771        C++ linking (needed for some HP-UX environments).
773    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
774        (unused parameter) and in the pcre_printint() function (omitted "default"
775        switch label when the default is to do nothing).
777    15. Added some code to make it possible, when PCRE is compiled as a C++
778        library, to replace subject pointers for pcre_exec() with a smart pointer
779        class, thus making it possible to process discontinuous strings.
781    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
782        much the same function. They were added by different people who were trying
783        to make PCRE easy to compile on non-Unix systems. It has been suggested
784        that PCRE_EXPORT be abolished now that there is more automatic apparatus
785        for compiling on Windows systems. I have therefore replaced it with
786        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
787        defaults to "extern" for C or "extern C" for C++, which works fine on
788        Unix-like systems. It is now possible to override the value of PCRE_DATA_
789        SCOPE with something explicit in config.h. In addition:
791        (a) pcreposix.h still had just "extern" instead of either of these macros;
792            I have replaced it with PCRE_DATA_SCOPE.
794        (b) Functions such as _pcre_xclass(), which are internal to the library,
795            but external in the C sense, all had PCRE_EXPORT in their definitions.
796            This is apparently wrong for the Windows case, so I have removed it.
797            (It makes no difference on Unix-like systems.)
799    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
800        of recursive calls to match(). This is different to MATCH_LIMIT because
801        that limits the total number of calls to match(), not all of which increase
802        the depth of recursion. Limiting the recursion depth limits the amount of
803        stack (or heap if NO_RECURSE is set) that is used. The default can be set
804        when PCRE is compiled, and changed at run time. A patch from Google adds
805        this functionality to the C++ interface.
807    18. Changes to the handling of Unicode character properties:
809        (a) Updated the table to Unicode 4.1.0.
811        (b) Recognize characters that are not in the table as "Cn" (undefined).
813        (c) I revised the way the table is implemented to a much improved format
814            which includes recognition of ranges. It now supports the ranges that
815            are defined in UnicodeData.txt, and it also amalgamates other
816            characters into ranges. This has reduced the number of entries in the
817            table from around 16,000 to around 3,000, thus reducing its size
818            considerably. I realized I did not need to use a tree structure after
819            all - a binary chop search is just as efficient. Having reduced the
820            number of entries, I extended their size from 6 bytes to 8 bytes to
821            allow for more data.
823        (d) Added support for Unicode script names via properties such as \p{Han}.
825    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
826        matching that character.
828    20. When matching a repeated Unicode property with a minimum greater than zero,
829        (for example \pL{2,}), PCRE could look past the end of the subject if it
830        reached it while seeking the minimum number of characters. This could
831        happen only if some of the characters were more than one byte long, because
832        there is a check for at least the minimum number of bytes.
834    21. Refactored the implementation of \p and \P so as to be more general, to
835        allow for more different types of property in future. This has changed the
836        compiled form incompatibly. Anybody with saved compiled patterns that use
837        \p or \P will have to recompile them.
839    22. Added "Any" and "L&" to the supported property types.
841    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
842        but give a compile time error if the value is greater than 0xff.
844    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
845        accidentally not being installed or uninstalled.
847    25. The pcre.h file was built from pcre.h.in, but the only changes that were
848        made were to insert the current release number. This seemed silly, because
849        it made things harder for people building PCRE on systems that don't run
850        "configure". I have turned pcre.h into a distributed file, no longer built
851        by "configure", with the version identification directly included. There is
852        no longer a pcre.h.in file.
854        However, this change necessitated a change to the pcre-config script as
855        well. It is built from pcre-config.in, and one of the substitutions was the
856        release number. I have updated configure.ac so that ./configure now finds
857        the release number by grepping pcre.h.
859    26. Added the ability to run the tests under valgrind.
862    Version 6.4 05-Sep-05
863    ---------------------
865     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
866        "--" to be printed when multiple files were scanned, even when none of the
867        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
868        consider it to be a bug, and have restored the previous behaviour.
870     2. A couple of code tidies to get rid of compiler warnings.
872     3. The pcretest program used to cheat by referring to symbols in the library
873        whose names begin with _pcre_. These are internal symbols that are not
874        really supposed to be visible externally, and in some environments it is
875        possible to suppress them. The cheating is now confined to including
876        certain files from the library's source, which is a bit cleaner.
878     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
879        file's purpose clearer.
881     5. Reorganized pcre_ucp_findchar().
884  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
885  ---------------------  ---------------------

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