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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.1 12-Mar-07
5    ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other Autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The 132html script that I use to generate
25        HTML has been updated to handle .nf/.fi and to complain if it encounters
26        .br or .in.
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, with the name
30        config.h.generic, for the benefit of those who have to compile without
31        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
33     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
34        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
35        makevp.bat for the current PCRE, using the additional files
36        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
38     6. A Windows user reported a minor discrepancy with test 2, which turned out
39        to be caused by a trailing space on an input line that had got lost in his
40        copy. The trailing space was an accident, so I've just removed it.
42     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
43        that is needed.
45     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
46        as "const" (a) because they are and (b) because it helps the PHP
47        maintainers who have recently made a script to detect big data structures
48        in the php code that should be moved to the .rodata section. I remembered
49        to update Builducptable as well, so it won't revert if ucptable.h is ever
50        re-created.
52     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
53        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
54        order to be able to cut out the UTF-8 tables in the latter when UTF-8
55        support is not required. This saves 1.5-2K of code, which is important in
56        some applications.
58        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
59        so as not to refer to the tables, even though these functions will never be
60        called when UTF-8 support is disabled. Otherwise there are problems with a
61        shared library.
63    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
65        (a) It was defining its arguments as char * instead of void *.
67        (b) It was assuming that all moves were upwards in memory; this was true
68            a long time ago when I wrote it, but is no longer the case.
70        The emulated memove() is provided for those environments that have neither
71        memmove() nor bcopy(). I didn't think anyone used it these days, but that
72        is clearly not the case, as these two bugs were recently reported.
74    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
75        and Detrail to create the HTML documentation, the .txt form of the man
76        pages, and it removes trailing spaces from listed files. It also creates
77        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
78        case, it wraps all the #defines with #ifndefs. This script should be run
79        before "make dist".
81    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
82        with Unicode property support.
84        (a) For a maximizing quantifier, if the two different cases of the
85            character were of different lengths in their UTF-8 codings (there are
86            some cases like this - I found 11), and the matching function had to
87            back up over a mixture of the two cases, it incorrectly assumed they
88            were both the same length.
90        (b) When PCRE was configured to use the heap rather than the stack for
91            recursion during matching, it was not correctly preserving the data for
92            the other case of a UTF-8 character when checking ahead for a match
93            while processing a minimizing repeat. If the check also involved
94            matching a wide character, but failed, corruption could cause an
95            erroneous result when trying to check for a repeat of the original
96            character.
98    13. Some tidying changes to the testing mechanism:
100        (a) The RunTest script now detects the internal link size and whether there
101            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
102            values substituted by "configure". (The RunGrepTest script already did
103            this for UTF-8.) The configure.ac script no longer substitutes the
104            relevant variables.
106        (b) The debugging options /B and /D in pcretest show the compiled bytecode
107            with length and offset values. This means that the output is different
108            for different internal link sizes. Test 2 is skipped for link sizes
109            other than 2 because of this, bypassing the problem. Unfortunately,
110            there was also a test in test 3 (the locale tests) that used /B and
111            failed for link sizes other than 2. Rather than cut the whole test out,
112            I have added a new /Z option to pcretest that replaces the length and
113            offset values with spaces. This is now used to make test 3 independent
114            of link size. (Test 2 will be tidied up later.)
116    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
117        segmentation fault instead of returning the appropriate error message.
119    15. In multiline mode when the newline sequence was set to "any", the pattern
120        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
121        This doesn't seem right; it now treats the CRLF combination as the line
122        ending, and so does not match in that case. It's only a pattern such as ^$
123        that would hit this one: something like ^ABC$ would have failed after \r
124        and then tried again after \r\n.
126    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
127        in an attempt to make files that differ only in their line terminators
128        compare equal. This works on Linux.
130    17. Under certain error circumstances pcregrep might try to free random memory
131        as it exited. This is now fixed, thanks to valgrind.
133    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
134        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
135        was because its rules for how to advance for /g after matching an empty
136        string at the end of a line did not allow for this case. They now check for
137        it specially.
139    20. pcretest is supposed to handle patterns and data of any length, by
140        extending its buffers when necessary. It was getting this wrong when the
141        buffer for a data line had to be extended.
144    Version 7.0 19-Dec-06
145    ---------------------
147     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
148        moving to gcc 4.1.1.
150     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
151        sys/time.h, which is documented as needed for this function. It doesn't
152        seem to matter on Linux, but it showed up on some releases of OS X.
154     3. It seems that there are systems where bytes whose values are greater than
155        127 match isprint() in the "C" locale. The "C" locale should be the
156        default when a C program starts up. In most systems, only ASCII printing
157        characters match isprint(). This difference caused the output from pcretest
158        to vary, making some of the tests fail. I have changed pcretest so that:
160        (a) When it is outputting text in the compiled version of a pattern, bytes
161            other than 32-126 are always shown as hex escapes.
163        (b) When it is outputting text that is a matched part of a subject string,
164            it does the same, unless a different locale has been set for the match
165            (using the /L modifier). In this case, it uses isprint() to decide.
167     4. Fixed a major bug that caused incorrect computation of the amount of memory
168        required for a compiled pattern when options that changed within the
169        pattern affected the logic of the preliminary scan that determines the
170        length. The relevant options are -x, and -i in UTF-8 mode. The result was
171        that the computed length was too small. The symptoms of this bug were
172        either the PCRE error "internal error: code overflow" from pcre_compile(),
173        or a glibc crash with a message such as "pcretest: free(): invalid next
174        size (fast)". Examples of patterns that provoked this bug (shown in
175        pcretest format) are:
177          /(?-x: )/x
178          /(?x)(?-x: \s*#\s*)/
179          /((?i)[\x{c0}])/8
180          /(?i:[\x{c0}])/8
182        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
183        is now done differently.
185     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
186        wrapper classes; (b) implement a new function in the C++ scanner that is
187        more efficient than the old way of doing things because it avoids levels of
188        recursion in the regex matching; (c) add a paragraph to the documentation
189        for the FullMatch() function.
191     6. The escape sequence \n was being treated as whatever was defined as
192        "newline". Not only was this contrary to the documentation, which states
193        that \n is character 10 (hex 0A), but it also went horribly wrong when
194        "newline" was defined as CRLF. This has been fixed.
196     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
197        was being set to -1 for the "end of line" case (supposedly a value that no
198        character can have). Though this value is never used (the check for end of
199        line is "zero bytes in current character"), it caused compiler complaints.
200        I've changed it to 0xffffffff.
202     8. In pcre_version.c, the version string was being built by a sequence of
203        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
204        string (as it is for production releases) called a macro with an empty
205        argument. The C standard says the result of this is undefined. The gcc
206        compiler treats it as an empty string (which was what was wanted) but it is
207        reported that Visual C gives an error. The source has been hacked around to
208        avoid this problem.
210     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
211        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
212        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
213        of them did).
215    10. Originally, pcretest opened its input and output without "b"; then I was
216        told that "b" was needed in some environments, so it was added for release
217        5.0 to both the input and output. (It makes no difference on Unix-like
218        systems.) Later I was told that it is wrong for the input on Windows. I've
219        now abstracted the modes into two macros, to make it easier to fiddle with
220        them, and removed "b" from the input mode under Windows.
222    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
224    12. Added -help and --help to pcretest as an official way of being reminded
225        of the options.
227    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
228        and pcrecpp.cc because they annoy compilers at high warning levels.
230    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
232    15. Fixed an occurrence of == in configure.ac that should have been = (shell
233        scripts are not C programs :-) and which was not noticed because it works
234        on Linux.
236    16. pcretest is supposed to handle any length of pattern and data line (as one
237        line or as a continued sequence of lines) by extending its input buffer if
238        necessary. This feature was broken for very long pattern lines, leading to
239        a string of junk being passed to pcre_compile() if the pattern was longer
240        than about 50K.
242    17. I have done a major re-factoring of the way pcre_compile() computes the
243        amount of memory needed for a compiled pattern. Previously, there was code
244        that made a preliminary scan of the pattern in order to do this. That was
245        OK when PCRE was new, but as the facilities have expanded, it has become
246        harder and harder to keep it in step with the real compile phase, and there
247        have been a number of bugs (see for example, 4 above). I have now found a
248        cunning way of running the real compile function in a "fake" mode that
249        enables it to compute how much memory it would need, while actually only
250        ever using a few hundred bytes of working memory and without too many
251        tests of the mode. This should make future maintenance and development
252        easier. A side effect of this work is that the limit of 200 on the nesting
253        depth of parentheses has been removed (though this was never a serious
254        limitation, I suspect). However, there is a downside: pcre_compile() now
255        runs more slowly than before (30% or more, depending on the pattern). I
256        hope this isn't a big issue. There is no effect on runtime performance.
258    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
259        newline (only possible for the last line of a file) and it was a
260        pattern that set a locale (followed by /Lsomething), pcretest crashed.
262    19. Added additional timing features to pcretest. (1) The -tm option now times
263        matching only, not compiling. (2) Both -t and -tm can be followed, as a
264        separate command line item, by a number that specifies the number of
265        repeats to use when timing. The default is 50000; this gives better
266        precision, but takes uncomfortably long for very large patterns.
268    20. Extended pcre_study() to be more clever in cases where a branch of a
269        subpattern has no definite first character. For example, (a*|b*)[cd] would
270        previously give no result from pcre_study(). Now it recognizes that the
271        first character must be a, b, c, or d.
273    21. There was an incorrect error "recursive call could loop indefinitely" if
274        a subpattern (or the entire pattern) that was being tested for matching an
275        empty string contained only one non-empty item after a nested subpattern.
276        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
277        incorrectly, because the \d was being skipped in the check.
279    22. The pcretest program now has a new pattern option /B and a command line
280        option -b, which is equivalent to adding /B to every pattern. This causes
281        it to show the compiled bytecode, without the additional information that
282        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
283        is the same as /B/I).
285    23. A new optimization is now able automatically to treat some sequences such
286        as a*b as a*+b. More specifically, if something simple (such as a character
287        or a simple class like \d) has an unlimited quantifier, and is followed by
288        something that cannot possibly match the quantified thing, the quantifier
289        is automatically "possessified".
291    24. A recursive reference to a subpattern whose number was greater than 39
292        went wrong under certain circumstances in UTF-8 mode. This bug could also
293        have affected the operation of pcre_study().
295    25. Realized that a little bit of performance could be had by replacing
296        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
298    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
300    27. Possessive quantifiers such as a++ were previously implemented by turning
301        them into atomic groups such as ($>a+). Now they have their own opcodes,
302        which improves performance. This includes the automatically created ones
303        from 23 above.
305    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
306        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
307        the first matched character to be a colon. This applied both to named and
308        numbered groups.
310    29. The ucpinternal.h header file was missing its idempotency #ifdef.
312    30. I was sent a "project" file called libpcre.a.dev which I understand makes
313        building PCRE on Windows easier, so I have included it in the distribution.
315    31. There is now a check in pcretest against a ridiculously large number being
316        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
317        loop, the loop is abandoned.
319    32. Forward references to subpatterns in conditions such as (?(2)...) where
320        subpattern 2 is defined later cause pcre_compile() to search forwards in
321        the pattern for the relevant set of parentheses. This search went wrong
322        when there were unescaped parentheses in a character class, parentheses
323        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
325    33. "Subroutine" calls and backreferences were previously restricted to
326        referencing subpatterns earlier in the regex. This restriction has now
327        been removed.
329    34. Added a number of extra features that are going to be in Perl 5.10. On the
330        whole, these are just syntactic alternatives for features that PCRE had
331        previously implemented using the Python syntax or my own invention. The
332        other formats are all retained for compatibility.
334        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
335            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
336            also .NET compatible.
338        (b) A recursion or subroutine call to a named group can now be defined as
339            (?&name) as well as (?P>name).
341        (c) A backreference to a named group can now be defined as \k<name> or
342            \k'name' as well as (?P=name). The new forms, as well as being in Perl
343            5.10, are also .NET compatible.
345        (d) A conditional reference to a named group can now use the syntax
346            (?(<name>) or (?('name') as well as (?(name).
348        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
349            groups (named and numbered) that are never evaluated inline, but can be
350            called as "subroutines" from elsewhere. In effect, the DEFINE condition
351            is always false. There may be only one alternative in such a group.
353        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
354            as the simple (?(R). The condition is true only if the most recent
355            recursion is that of the given number or name. It does not search out
356            through the entire recursion stack.
358        (g) The escape \gN or \g{N} has been added, where N is a positive or
359            negative number, specifying an absolute or relative reference.
361    35. Tidied to get rid of some further signed/unsigned compiler warnings and
362        some "unreachable code" warnings.
364    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
365        things, this adds five new scripts.
367    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
368        There were also incompatibilities regarding the handling of \Q..\E inside
369        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
370        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
372    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
373        matches an empty string, and forcibly breaks the loop. There were bugs in
374        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
375        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
376        separate and independent bugs (that affected different cases) have been
377        fixed.
379    39. Refactored the code to abolish the use of different opcodes for small
380        capturing bracket numbers. This is a tidy that I avoided doing when I
381        removed the limit on the number of capturing brackets for 3.5 back in 2001.
382        The new approach is not only tidier, it makes it possible to reduce the
383        memory needed to fix the previous bug (38).
385    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
386        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
387        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
388        mode.
390    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
391        report.
393    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
394        copy construction and assignment in the C++ wrapper.
396    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
397        couple of bugs that could have given wrong results in the "--newline=crlf"
398        case.
400    44. Added a number of casts and did some reorganization of signed/unsigned int
401        variables following suggestions from Dair Grant. Also renamed the variable
402        "this" as "item" because it is a C++ keyword.
404    45. Arranged for dftables to add
406          #include "pcre_internal.h"
408        to pcre_chartables.c because without it, gcc 4.x may remove the array
409        definition from the final binary if PCRE is built into a static library and
410        dead code stripping is activated.
412    46. For an unanchored pattern, if a match attempt fails at the start of a
413        newline sequence, and the newline setting is CRLF or ANY, and the next two
414        characters are CRLF, advance by two characters instead of one.
417    Version 6.7 04-Jul-06
418    ---------------------
420     1. In order to handle tests when input lines are enormously long, pcretest has
421        been re-factored so that it automatically extends its buffers when
422        necessary. The code is crude, but this _is_ just a test program. The
423        default size has been increased from 32K to 50K.
425     2. The code in pcre_study() was using the value of the re argument before
426        testing it for NULL. (Of course, in any sensible call of the function, it
427        won't be NULL.)
429     3. The memmove() emulation function in pcre_internal.h, which is used on
430        systems that lack both memmove() and bcopy() - that is, hardly ever -
431        was missing a "static" storage class specifier.
433     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
434        containing an extended class (one that cannot be represented by a bitmap
435        because it contains high-valued characters or Unicode property items, e.g.
436        [\pZ]). Almost always one would set UTF-8 mode when processing such a
437        pattern, but PCRE should not loop if you do not (it no longer does).
438        [Detail: two cases were found: (a) a repeated subpattern containing an
439        extended class; (b) a recursive reference to a subpattern that followed a
440        previous extended class. It wasn't skipping over the extended class
441        correctly when UTF-8 mode was not set.]
443     5. A negated single-character class was not being recognized as fixed-length
444        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
445        compile error "lookbehind assertion is not fixed length".
447     6. The RunPerlTest auxiliary script was showing an unexpected difference
448        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
449        write a Perl script that can interpret lines of an input file either as
450        byte characters or as UTF-8, which is what "perltest" was being required to
451        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
452        can't do is switch easily at run time between having the "use utf8;" pragma
453        or not. In the end, I fudged it by using the RunPerlTest script to insert
454        "use utf8;" explicitly for the UTF-8 tests.
456     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
457        the end of the subject string, contrary to the documentation and to what
458        Perl does. This was true of both matching functions. Now it matches only at
459        the start of the subject and immediately after *internal* newlines.
461     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
462        a pointer to an int instead of a pointer to an unsigned long int. This
463        caused problems on 64-bit systems.
465     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
466        instance of the 'standard' template library not being so standard".
468    10. There was no check on the number of named subpatterns nor the maximum
469        length of a subpattern name. The product of these values is used to compute
470        the size of the memory block for a compiled pattern. By supplying a very
471        long subpattern name and a large number of named subpatterns, the size
472        computation could be caused to overflow. This is now prevented by limiting
473        the length of names to 32 characters, and the number of named subpatterns
474        to 10,000.
476    11. Subpatterns that are repeated with specific counts have to be replicated in
477        the compiled pattern. The size of memory for this was computed from the
478        length of the subpattern and the repeat count. The latter is limited to
479        65535, but there was no limit on the former, meaning that integer overflow
480        could in principle occur. The compiled length of a repeated subpattern is
481        now limited to 30,000 bytes in order to prevent this.
483    12. Added the optional facility to have named substrings with the same name.
485    13. Added the ability to use a named substring as a condition, using the
486        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
487        are numbers (not recommended). Forward references are permitted.
489    14. Added forward references in named backreferences (if you see what I mean).
491    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
492        pattern could run off the end of the subject. For example, the pattern
493        "(?s)(.{1,5})"8 did this with the subject "ab".
495    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
496        PCRE_CASELESS was set when matching characters that were quantified with ?
497        or *.
499    17. A character class other than a single negated character that had a minimum
500        but no maximum quantifier - for example [ab]{6,} - was not handled
501        correctly by pce_dfa_exec(). It would match only one character.
503    18. A valid (though odd) pattern that looked like a POSIX character
504        class but used an invalid character after [ (for example [[,abc,]]) caused
505        pcre_compile() to give the error "Failed: internal error: code overflow" or
506        in some cases to crash with a glibc free() error. This could even happen if
507        the pattern terminated after [[ but there just happened to be a sequence of
508        letters, a binary zero, and a closing ] in the memory that followed.
510    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
511        over the years. Originally (before any Unicode support), just the bottom 8
512        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
513        output from "man perlunicode" includes this:
515          The regular expression compiler produces polymorphic opcodes.  That
516          is, the pattern adapts to the data and automatically switches to
517          the Unicode character scheme when presented with Unicode data--or
518          instead uses a traditional byte scheme when presented with byte
519          data.
521        Sadly, a wide octal escape does not cause a switch, and in a string with
522        no other multibyte characters, these octal escapes are treated as before.
523        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
524        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
525        Unicode string.
527        I have not perpetrated such confusion in PCRE. Up till now, it took just
528        the bottom 8 bits, as in old Perl. I have now made octal escapes with
529        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
530        translate to the appropriate multibyte character.
532    29. Applied some refactoring to reduce the number of warnings from Microsoft
533        and Borland compilers. This has included removing the fudge introduced
534        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
535        a warning about an unused variable.
537    21. PCRE has not included VT (character 0x0b) in the set of whitespace
538        characters since release 4.0, because Perl (from release 5.004) does not.
539        [Or at least, is documented not to: some releases seem to be in conflict
540        with the documentation.] However, when a pattern was studied with
541        pcre_study() and all its branches started with \s, PCRE still included VT
542        as a possible starting character. Of course, this did no harm; it just
543        caused an unnecessary match attempt.
545    22. Removed a now-redundant internal flag bit that recorded the fact that case
546        dependency changed within the pattern. This was once needed for "required
547        byte" processing, but is no longer used. This recovers a now-scarce options
548        bit. Also moved the least significant internal flag bit to the most-
549        significant bit of the word, which was not previously used (hangover from
550        the days when it was an int rather than a uint) to free up another bit for
551        the future.
553    23. Added support for CRLF line endings as well as CR and LF. As well as the
554        default being selectable at build time, it can now be changed at runtime
555        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
556        specify that it is scanning data with non-default line endings.
558    24. Changed the definition of CXXLINK to make it agree with the definition of
559        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
561    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
562        recursions. This makes a big different to stack usage for some patterns.
564    26. If a subpattern containing a named recursion or subroutine reference such
565        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
566        the space required for the compiled pattern went wrong and gave too small a
567        value. Depending on the environment, this could lead to "Failed: internal
568        error: code overflow at offset 49" or "glibc detected double free or
569        corruption" errors.
571    27. Applied patches from Google (a) to support the new newline modes and (b) to
572        advance over multibyte UTF-8 characters in GlobalReplace.
574    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
575        difference for some implementation of PCRE in some Windows version.
577    29. Added some extra testing facilities to pcretest:
579        \q<number>   in a data line sets the "match limit" value
580        \Q<number>   in a data line sets the "match recursion limt" value
581        -S <number>  sets the stack size, where <number> is in megabytes
583        The -S option isn't available for Windows.
586    Version 6.6 06-Feb-06
587    ---------------------
589     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
590        in pcreposix.h. I have copied the definition from pcre.h.
592     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
593        because pcre.h is no longer a built file.
595     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
596        not normally included in the compiled code.
599    Version 6.5 01-Feb-06
600    ---------------------
602     1. When using the partial match feature with pcre_dfa_exec(), it was not
603        anchoring the second and subsequent partial matches at the new starting
604        point. This could lead to incorrect results. For example, with the pattern
605        /1234/, partially matching against "123" and then "a4" gave a match.
607     2. Changes to pcregrep:
609        (a) All non-match returns from pcre_exec() were being treated as failures
610            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
611            error message is output. Some extra information is given for the
612            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
613            probably the only errors that are likely to be caused by users (by
614            specifying a regex that has nested indefinite repeats, for instance).
615            If there are more than 20 of these errors, pcregrep is abandoned.
617        (b) A binary zero was treated as data while matching, but terminated the
618            output line if it was written out. This has been fixed: binary zeroes
619            are now no different to any other data bytes.
621        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
622            used to set a locale for matching. The --locale=xxxx long option has
623            been added (no short equivalent) to specify a locale explicitly on the
624            pcregrep command, overriding the environment variables.
626        (d) When -B was used with -n, some line numbers in the output were one less
627            than they should have been.
629        (e) Added the -o (--only-matching) option.
631        (f) If -A or -C was used with -c (count only), some lines of context were
632            accidentally printed for the final match.
634        (g) Added the -H (--with-filename) option.
636        (h) The combination of options -rh failed to suppress file names for files
637            that were found from directory arguments.
639        (i) Added the -D (--devices) and -d (--directories) options.
641        (j) Added the -F (--fixed-strings) option.
643        (k) Allow "-" to be used as a file name for -f as well as for a data file.
645        (l) Added the --colo(u)r option.
647        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
648            is not present by default.
650     3. A nasty bug was discovered in the handling of recursive patterns, that is,
651        items such as (?R) or (?1), when the recursion could match a number of
652        alternatives. If it matched one of the alternatives, but subsequently,
653        outside the recursion, there was a failure, the code tried to back up into
654        the recursion. However, because of the way PCRE is implemented, this is not
655        possible, and the result was an incorrect result from the match.
657        In order to prevent this happening, the specification of recursion has
658        been changed so that all such subpatterns are automatically treated as
659        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
661     4. I had overlooked the fact that, in some locales, there are characters for
662        which isalpha() is true but neither isupper() nor islower() are true. In
663        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
664        and ordfeminine) are like this. This affected the treatment of \w and \W
665        when they appeared in character classes, but not when they appeared outside
666        a character class. The bit map for "word" characters is now created
667        separately from the results of isalnum() instead of just taking it from the
668        upper, lower, and digit maps. (Plus the underscore character, of course.)
670     5. The above bug also affected the handling of POSIX character classes such as
671        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
672        permanent tables. Instead, the bit maps for such a class were previously
673        created as the appropriate unions of the upper, lower, and digit bitmaps.
674        Now they are created by subtraction from the [[:word:]] class, which has
675        its own bitmap.
677     6. The [[:blank:]] character class matches horizontal, but not vertical space.
678        It is created by subtracting the vertical space characters (\x09, \x0a,
679        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
680        subtraction was done in the overall bitmap for a character class, meaning
681        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
682        be recognized. This bug has been fixed.
684     7. Patches from the folks at Google:
686          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
687          real life, but is still worth protecting against".
689          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
690          regular expressions".
692          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
693          have it.
695          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
696          "configure" and the latter not, in order to fix a problem somebody had
697          with compiling the Arg class on HP-UX.
699          (e) Improve the error-handling of the C++ wrapper a little bit.
701          (f) New tests for checking recursion limiting.
703     8. The pcre_memmove() function, which is used only if the environment does not
704        have a standard memmove() function (and is therefore rarely compiled),
705        contained two bugs: (a) use of int instead of size_t, and (b) it was not
706        returning a result (though PCRE never actually uses the result).
708     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
709        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
710        returned instead of calling malloc() with an overflowing number that would
711        most likely cause subsequent chaos.
713    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
715    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
716        with this option is matched, the nmatch and pmatch options of regexec() are
717        ignored.
719    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
720        provided in case anyone wants to the the POSIX interface with UTF-8
721        strings.
723    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
724        C++ linking (needed for some HP-UX environments).
726    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
727        (unused parameter) and in the pcre_printint() function (omitted "default"
728        switch label when the default is to do nothing).
730    15. Added some code to make it possible, when PCRE is compiled as a C++
731        library, to replace subject pointers for pcre_exec() with a smart pointer
732        class, thus making it possible to process discontinuous strings.
734    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
735        much the same function. They were added by different people who were trying
736        to make PCRE easy to compile on non-Unix systems. It has been suggested
737        that PCRE_EXPORT be abolished now that there is more automatic apparatus
738        for compiling on Windows systems. I have therefore replaced it with
739        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
740        defaults to "extern" for C or "extern C" for C++, which works fine on
741        Unix-like systems. It is now possible to override the value of PCRE_DATA_
742        SCOPE with something explicit in config.h. In addition:
744        (a) pcreposix.h still had just "extern" instead of either of these macros;
745            I have replaced it with PCRE_DATA_SCOPE.
747        (b) Functions such as _pcre_xclass(), which are internal to the library,
748            but external in the C sense, all had PCRE_EXPORT in their definitions.
749            This is apparently wrong for the Windows case, so I have removed it.
750            (It makes no difference on Unix-like systems.)
752    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
753        of recursive calls to match(). This is different to MATCH_LIMIT because
754        that limits the total number of calls to match(), not all of which increase
755        the depth of recursion. Limiting the recursion depth limits the amount of
756        stack (or heap if NO_RECURSE is set) that is used. The default can be set
757        when PCRE is compiled, and changed at run time. A patch from Google adds
758        this functionality to the C++ interface.
760    18. Changes to the handling of Unicode character properties:
762        (a) Updated the table to Unicode 4.1.0.
764        (b) Recognize characters that are not in the table as "Cn" (undefined).
766        (c) I revised the way the table is implemented to a much improved format
767            which includes recognition of ranges. It now supports the ranges that
768            are defined in UnicodeData.txt, and it also amalgamates other
769            characters into ranges. This has reduced the number of entries in the
770            table from around 16,000 to around 3,000, thus reducing its size
771            considerably. I realized I did not need to use a tree structure after
772            all - a binary chop search is just as efficient. Having reduced the
773            number of entries, I extended their size from 6 bytes to 8 bytes to
774            allow for more data.
776        (d) Added support for Unicode script names via properties such as \p{Han}.
778    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
779        matching that character.
781    20. When matching a repeated Unicode property with a minimum greater than zero,
782        (for example \pL{2,}), PCRE could look past the end of the subject if it
783        reached it while seeking the minimum number of characters. This could
784        happen only if some of the characters were more than one byte long, because
785        there is a check for at least the minimum number of bytes.
787    21. Refactored the implementation of \p and \P so as to be more general, to
788        allow for more different types of property in future. This has changed the
789        compiled form incompatibly. Anybody with saved compiled patterns that use
790        \p or \P will have to recompile them.
792    22. Added "Any" and "L&" to the supported property types.
794    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
795        but give a compile time error if the value is greater than 0xff.
797    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
798        accidentally not being installed or uninstalled.
800    25. The pcre.h file was built from pcre.h.in, but the only changes that were
801        made were to insert the current release number. This seemed silly, because
802        it made things harder for people building PCRE on systems that don't run
803        "configure". I have turned pcre.h into a distributed file, no longer built
804        by "configure", with the version identification directly included. There is
805        no longer a pcre.h.in file.
807        However, this change necessitated a change to the pcre-config script as
808        well. It is built from pcre-config.in, and one of the substitutions was the
809        release number. I have updated configure.ac so that ./configure now finds
810        the release number by grepping pcre.h.
812    26. Added the ability to run the tests under valgrind.
815    Version 6.4 05-Sep-05
816    ---------------------
818     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
819        "--" to be printed when multiple files were scanned, even when none of the
820        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
821        consider it to be a bug, and have restored the previous behaviour.
823     2. A couple of code tidies to get rid of compiler warnings.
825     3. The pcretest program used to cheat by referring to symbols in the library
826        whose names begin with _pcre_. These are internal symbols that are not
827        really supposed to be visible externally, and in some environments it is
828        possible to suppress them. The cheating is now confined to including
829        certain files from the library's source, which is a bit cleaner.
831     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
832        file's purpose clearer.
834     5. Reorganized pcre_ucp_findchar().
837  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
838  ---------------------  ---------------------

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