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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 157 by ph10, Tue May 1 09:19:56 2007 UTC
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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.
11    Version 7.1 24-Apr-07
12    ---------------------
14     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
15        that is more "standard", making use of automake and other Autotools. There
16        is some re-arrangement of the files and adjustment of comments consequent
17        on this.
19     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
20        for recursive directory scanning broke on some systems because the files
21        are not scanned in any specific order and on different systems the order
22        was different. A call to "sort" has been inserted into RunGrepTest for the
23        approprate test as a short-term fix. In the longer term there may be an
24        alternative.
26     3. I had an email from Eric Raymond about problems translating some of PCRE's
27        man pages to HTML (despite the fact that I distribute HTML pages, some
28        people do their own conversions for various reasons). The problems
29        concerned the use of low-level troff macros .br and .in. I have therefore
30        removed all such uses from the man pages (some were redundant, some could
31        be replaced by .nf/.fi pairs). The 132html script that I use to generate
32        HTML has been updated to handle .nf/.fi and to complain if it encounters
33        .br or .in.
35     4. Updated comments in configure.ac that get placed in config.h.in and also
36        arranged for config.h to be included in the distribution, with the name
37        config.h.generic, for the benefit of those who have to compile without
38        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
40     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
41        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
42        makevp.bat for the current PCRE, using the additional files
43        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
45     6. A Windows user reported a minor discrepancy with test 2, which turned out
46        to be caused by a trailing space on an input line that had got lost in his
47        copy. The trailing space was an accident, so I've just removed it.
49     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
50        that is needed.
52     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
53        as "const" (a) because they are and (b) because it helps the PHP
54        maintainers who have recently made a script to detect big data structures
55        in the php code that should be moved to the .rodata section. I remembered
56        to update Builducptable as well, so it won't revert if ucptable.h is ever
57        re-created.
59     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
60        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
61        order to be able to cut out the UTF-8 tables in the latter when UTF-8
62        support is not required. This saves 1.5-2K of code, which is important in
63        some applications.
65        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
66        so as not to refer to the tables, even though these functions will never be
67        called when UTF-8 support is disabled. Otherwise there are problems with a
68        shared library.
70    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
72        (a) It was defining its arguments as char * instead of void *.
74        (b) It was assuming that all moves were upwards in memory; this was true
75            a long time ago when I wrote it, but is no longer the case.
77        The emulated memove() is provided for those environments that have neither
78        memmove() nor bcopy(). I didn't think anyone used it these days, but that
79        is clearly not the case, as these two bugs were recently reported.
81    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
82        and Detrail to create the HTML documentation, the .txt form of the man
83        pages, and it removes trailing spaces from listed files. It also creates
84        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
85        case, it wraps all the #defines with #ifndefs. This script should be run
86        before "make dist".
88    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
89        with Unicode property support.
91        (a) For a maximizing quantifier, if the two different cases of the
92            character were of different lengths in their UTF-8 codings (there are
93            some cases like this - I found 11), and the matching function had to
94            back up over a mixture of the two cases, it incorrectly assumed they
95            were both the same length.
97        (b) When PCRE was configured to use the heap rather than the stack for
98            recursion during matching, it was not correctly preserving the data for
99            the other case of a UTF-8 character when checking ahead for a match
100            while processing a minimizing repeat. If the check also involved
101            matching a wide character, but failed, corruption could cause an
102            erroneous result when trying to check for a repeat of the original
103            character.
105    13. Some tidying changes to the testing mechanism:
107        (a) The RunTest script now detects the internal link size and whether there
108            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
109            values substituted by "configure". (The RunGrepTest script already did
110            this for UTF-8.) The configure.ac script no longer substitutes the
111            relevant variables.
113        (b) The debugging options /B and /D in pcretest show the compiled bytecode
114            with length and offset values. This means that the output is different
115            for different internal link sizes. Test 2 is skipped for link sizes
116            other than 2 because of this, bypassing the problem. Unfortunately,
117            there was also a test in test 3 (the locale tests) that used /B and
118            failed for link sizes other than 2. Rather than cut the whole test out,
119            I have added a new /Z option to pcretest that replaces the length and
120            offset values with spaces. This is now used to make test 3 independent
121            of link size. (Test 2 will be tidied up later.)
123    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
124        segmentation fault instead of returning the appropriate error message.
126    15. In multiline mode when the newline sequence was set to "any", the pattern
127        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
128        This doesn't seem right; it now treats the CRLF combination as the line
129        ending, and so does not match in that case. It's only a pattern such as ^$
130        that would hit this one: something like ^ABC$ would have failed after \r
131        and then tried again after \r\n.
133    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
134        in an attempt to make files that differ only in their line terminators
135        compare equal. This works on Linux.
137    17. Under certain error circumstances pcregrep might try to free random memory
138        as it exited. This is now fixed, thanks to valgrind.
140    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
141        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
142        was because its rules for how to advance for /g after matching an empty
143        string at the end of a line did not allow for this case. They now check for
144        it specially.
146    20. pcretest is supposed to handle patterns and data of any length, by
147        extending its buffers when necessary. It was getting this wrong when the
148        buffer for a data line had to be extended.
150    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
151        CRLF as a newline sequence.
153    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
154        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
155        I have nevertheless tidied it up.
157    23. Added some casts to kill warnings from HP-UX ia64 compiler.
159    24. Added a man page for pcre-config.
162    Version 7.0 19-Dec-06
163    ---------------------
165     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
166        moving to gcc 4.1.1.
168     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
169        sys/time.h, which is documented as needed for this function. It doesn't
170        seem to matter on Linux, but it showed up on some releases of OS X.
172     3. It seems that there are systems where bytes whose values are greater than
173        127 match isprint() in the "C" locale. The "C" locale should be the
174        default when a C program starts up. In most systems, only ASCII printing
175        characters match isprint(). This difference caused the output from pcretest
176        to vary, making some of the tests fail. I have changed pcretest so that:
178        (a) When it is outputting text in the compiled version of a pattern, bytes
179            other than 32-126 are always shown as hex escapes.
181        (b) When it is outputting text that is a matched part of a subject string,
182            it does the same, unless a different locale has been set for the match
183            (using the /L modifier). In this case, it uses isprint() to decide.
185     4. Fixed a major bug that caused incorrect computation of the amount of memory
186        required for a compiled pattern when options that changed within the
187        pattern affected the logic of the preliminary scan that determines the
188        length. The relevant options are -x, and -i in UTF-8 mode. The result was
189        that the computed length was too small. The symptoms of this bug were
190        either the PCRE error "internal error: code overflow" from pcre_compile(),
191        or a glibc crash with a message such as "pcretest: free(): invalid next
192        size (fast)". Examples of patterns that provoked this bug (shown in
193        pcretest format) are:
195          /(?-x: )/x
196          /(?x)(?-x: \s*#\s*)/
197          /((?i)[\x{c0}])/8
198          /(?i:[\x{c0}])/8
200        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
201        is now done differently.
203     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
204        wrapper classes; (b) implement a new function in the C++ scanner that is
205        more efficient than the old way of doing things because it avoids levels of
206        recursion in the regex matching; (c) add a paragraph to the documentation
207        for the FullMatch() function.
209     6. The escape sequence \n was being treated as whatever was defined as
210        "newline". Not only was this contrary to the documentation, which states
211        that \n is character 10 (hex 0A), but it also went horribly wrong when
212        "newline" was defined as CRLF. This has been fixed.
214     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
215        was being set to -1 for the "end of line" case (supposedly a value that no
216        character can have). Though this value is never used (the check for end of
217        line is "zero bytes in current character"), it caused compiler complaints.
218        I've changed it to 0xffffffff.
220     8. In pcre_version.c, the version string was being built by a sequence of
221        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
222        string (as it is for production releases) called a macro with an empty
223        argument. The C standard says the result of this is undefined. The gcc
224        compiler treats it as an empty string (which was what was wanted) but it is
225        reported that Visual C gives an error. The source has been hacked around to
226        avoid this problem.
228     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
229        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
230        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
231        of them did).
233    10. Originally, pcretest opened its input and output without "b"; then I was
234        told that "b" was needed in some environments, so it was added for release
235        5.0 to both the input and output. (It makes no difference on Unix-like
236        systems.) Later I was told that it is wrong for the input on Windows. I've
237        now abstracted the modes into two macros, to make it easier to fiddle with
238        them, and removed "b" from the input mode under Windows.
240    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
242    12. Added -help and --help to pcretest as an official way of being reminded
243        of the options.
245    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
246        and pcrecpp.cc because they annoy compilers at high warning levels.
248    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
250    15. Fixed an occurrence of == in configure.ac that should have been = (shell
251        scripts are not C programs :-) and which was not noticed because it works
252        on Linux.
254    16. pcretest is supposed to handle any length of pattern and data line (as one
255        line or as a continued sequence of lines) by extending its input buffer if
256        necessary. This feature was broken for very long pattern lines, leading to
257        a string of junk being passed to pcre_compile() if the pattern was longer
258        than about 50K.
260    17. I have done a major re-factoring of the way pcre_compile() computes the
261        amount of memory needed for a compiled pattern. Previously, there was code
262        that made a preliminary scan of the pattern in order to do this. That was
263        OK when PCRE was new, but as the facilities have expanded, it has become
264        harder and harder to keep it in step with the real compile phase, and there
265        have been a number of bugs (see for example, 4 above). I have now found a
266        cunning way of running the real compile function in a "fake" mode that
267        enables it to compute how much memory it would need, while actually only
268        ever using a few hundred bytes of working memory and without too many
269        tests of the mode. This should make future maintenance and development
270        easier. A side effect of this work is that the limit of 200 on the nesting
271        depth of parentheses has been removed (though this was never a serious
272        limitation, I suspect). However, there is a downside: pcre_compile() now
273        runs more slowly than before (30% or more, depending on the pattern). I
274        hope this isn't a big issue. There is no effect on runtime performance.
276    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
277        newline (only possible for the last line of a file) and it was a
278        pattern that set a locale (followed by /Lsomething), pcretest crashed.
280    19. Added additional timing features to pcretest. (1) The -tm option now times
281        matching only, not compiling. (2) Both -t and -tm can be followed, as a
282        separate command line item, by a number that specifies the number of
283        repeats to use when timing. The default is 50000; this gives better
284        precision, but takes uncomfortably long for very large patterns.
286    20. Extended pcre_study() to be more clever in cases where a branch of a
287        subpattern has no definite first character. For example, (a*|b*)[cd] would
288        previously give no result from pcre_study(). Now it recognizes that the
289        first character must be a, b, c, or d.
291    21. There was an incorrect error "recursive call could loop indefinitely" if
292        a subpattern (or the entire pattern) that was being tested for matching an
293        empty string contained only one non-empty item after a nested subpattern.
294        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
295        incorrectly, because the \d was being skipped in the check.
297    22. The pcretest program now has a new pattern option /B and a command line
298        option -b, which is equivalent to adding /B to every pattern. This causes
299        it to show the compiled bytecode, without the additional information that
300        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
301        is the same as /B/I).
303    23. A new optimization is now able automatically to treat some sequences such
304        as a*b as a*+b. More specifically, if something simple (such as a character
305        or a simple class like \d) has an unlimited quantifier, and is followed by
306        something that cannot possibly match the quantified thing, the quantifier
307        is automatically "possessified".
309    24. A recursive reference to a subpattern whose number was greater than 39
310        went wrong under certain circumstances in UTF-8 mode. This bug could also
311        have affected the operation of pcre_study().
313    25. Realized that a little bit of performance could be had by replacing
314        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
316    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
318    27. Possessive quantifiers such as a++ were previously implemented by turning
319        them into atomic groups such as ($>a+). Now they have their own opcodes,
320        which improves performance. This includes the automatically created ones
321        from 23 above.
323    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
324        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
325        the first matched character to be a colon. This applied both to named and
326        numbered groups.
328    29. The ucpinternal.h header file was missing its idempotency #ifdef.
330    30. I was sent a "project" file called libpcre.a.dev which I understand makes
331        building PCRE on Windows easier, so I have included it in the distribution.
333    31. There is now a check in pcretest against a ridiculously large number being
334        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
335        loop, the loop is abandoned.
337    32. Forward references to subpatterns in conditions such as (?(2)...) where
338        subpattern 2 is defined later cause pcre_compile() to search forwards in
339        the pattern for the relevant set of parentheses. This search went wrong
340        when there were unescaped parentheses in a character class, parentheses
341        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
343    33. "Subroutine" calls and backreferences were previously restricted to
344        referencing subpatterns earlier in the regex. This restriction has now
345        been removed.
347    34. Added a number of extra features that are going to be in Perl 5.10. On the
348        whole, these are just syntactic alternatives for features that PCRE had
349        previously implemented using the Python syntax or my own invention. The
350        other formats are all retained for compatibility.
352        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
353            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
354            also .NET compatible.
356        (b) A recursion or subroutine call to a named group can now be defined as
357            (?&name) as well as (?P>name).
359        (c) A backreference to a named group can now be defined as \k<name> or
360            \k'name' as well as (?P=name). The new forms, as well as being in Perl
361            5.10, are also .NET compatible.
363        (d) A conditional reference to a named group can now use the syntax
364            (?(<name>) or (?('name') as well as (?(name).
366        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
367            groups (named and numbered) that are never evaluated inline, but can be
368            called as "subroutines" from elsewhere. In effect, the DEFINE condition
369            is always false. There may be only one alternative in such a group.
371        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
372            as the simple (?(R). The condition is true only if the most recent
373            recursion is that of the given number or name. It does not search out
374            through the entire recursion stack.
376        (g) The escape \gN or \g{N} has been added, where N is a positive or
377            negative number, specifying an absolute or relative reference.
379    35. Tidied to get rid of some further signed/unsigned compiler warnings and
380        some "unreachable code" warnings.
382    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
383        things, this adds five new scripts.
385    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
386        There were also incompatibilities regarding the handling of \Q..\E inside
387        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
388        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
390    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
391        matches an empty string, and forcibly breaks the loop. There were bugs in
392        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
393        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
394        separate and independent bugs (that affected different cases) have been
395        fixed.
397    39. Refactored the code to abolish the use of different opcodes for small
398        capturing bracket numbers. This is a tidy that I avoided doing when I
399        removed the limit on the number of capturing brackets for 3.5 back in 2001.
400        The new approach is not only tidier, it makes it possible to reduce the
401        memory needed to fix the previous bug (38).
403    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
404        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
405        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
406        mode.
408    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
409        report.
411    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
412        copy construction and assignment in the C++ wrapper.
414    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
415        couple of bugs that could have given wrong results in the "--newline=crlf"
416        case.
418    44. Added a number of casts and did some reorganization of signed/unsigned int
419        variables following suggestions from Dair Grant. Also renamed the variable
420        "this" as "item" because it is a C++ keyword.
422    45. Arranged for dftables to add
424          #include "pcre_internal.h"
426        to pcre_chartables.c because without it, gcc 4.x may remove the array
427        definition from the final binary if PCRE is built into a static library and
428        dead code stripping is activated.
430    46. For an unanchored pattern, if a match attempt fails at the start of a
431        newline sequence, and the newline setting is CRLF or ANY, and the next two
432        characters are CRLF, advance by two characters instead of one.
435    Version 6.7 04-Jul-06
436    ---------------------
438     1. In order to handle tests when input lines are enormously long, pcretest has
439        been re-factored so that it automatically extends its buffers when
440        necessary. The code is crude, but this _is_ just a test program. The
441        default size has been increased from 32K to 50K.
443     2. The code in pcre_study() was using the value of the re argument before
444        testing it for NULL. (Of course, in any sensible call of the function, it
445        won't be NULL.)
447     3. The memmove() emulation function in pcre_internal.h, which is used on
448        systems that lack both memmove() and bcopy() - that is, hardly ever -
449        was missing a "static" storage class specifier.
451     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
452        containing an extended class (one that cannot be represented by a bitmap
453        because it contains high-valued characters or Unicode property items, e.g.
454        [\pZ]). Almost always one would set UTF-8 mode when processing such a
455        pattern, but PCRE should not loop if you do not (it no longer does).
456        [Detail: two cases were found: (a) a repeated subpattern containing an
457        extended class; (b) a recursive reference to a subpattern that followed a
458        previous extended class. It wasn't skipping over the extended class
459        correctly when UTF-8 mode was not set.]
461     5. A negated single-character class was not being recognized as fixed-length
462        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
463        compile error "lookbehind assertion is not fixed length".
465     6. The RunPerlTest auxiliary script was showing an unexpected difference
466        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
467        write a Perl script that can interpret lines of an input file either as
468        byte characters or as UTF-8, which is what "perltest" was being required to
469        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
470        can't do is switch easily at run time between having the "use utf8;" pragma
471        or not. In the end, I fudged it by using the RunPerlTest script to insert
472        "use utf8;" explicitly for the UTF-8 tests.
474     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
475        the end of the subject string, contrary to the documentation and to what
476        Perl does. This was true of both matching functions. Now it matches only at
477        the start of the subject and immediately after *internal* newlines.
479     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
480        a pointer to an int instead of a pointer to an unsigned long int. This
481        caused problems on 64-bit systems.
483     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
484        instance of the 'standard' template library not being so standard".
486    10. There was no check on the number of named subpatterns nor the maximum
487        length of a subpattern name. The product of these values is used to compute
488        the size of the memory block for a compiled pattern. By supplying a very
489        long subpattern name and a large number of named subpatterns, the size
490        computation could be caused to overflow. This is now prevented by limiting
491        the length of names to 32 characters, and the number of named subpatterns
492        to 10,000.
494    11. Subpatterns that are repeated with specific counts have to be replicated in
495        the compiled pattern. The size of memory for this was computed from the
496        length of the subpattern and the repeat count. The latter is limited to
497        65535, but there was no limit on the former, meaning that integer overflow
498        could in principle occur. The compiled length of a repeated subpattern is
499        now limited to 30,000 bytes in order to prevent this.
501    12. Added the optional facility to have named substrings with the same name.
503    13. Added the ability to use a named substring as a condition, using the
504        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
505        are numbers (not recommended). Forward references are permitted.
507    14. Added forward references in named backreferences (if you see what I mean).
509    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
510        pattern could run off the end of the subject. For example, the pattern
511        "(?s)(.{1,5})"8 did this with the subject "ab".
513    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
514        PCRE_CASELESS was set when matching characters that were quantified with ?
515        or *.
517    17. A character class other than a single negated character that had a minimum
518        but no maximum quantifier - for example [ab]{6,} - was not handled
519        correctly by pce_dfa_exec(). It would match only one character.
521    18. A valid (though odd) pattern that looked like a POSIX character
522        class but used an invalid character after [ (for example [[,abc,]]) caused
523        pcre_compile() to give the error "Failed: internal error: code overflow" or
524        in some cases to crash with a glibc free() error. This could even happen if
525        the pattern terminated after [[ but there just happened to be a sequence of
526        letters, a binary zero, and a closing ] in the memory that followed.
528    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
529        over the years. Originally (before any Unicode support), just the bottom 8
530        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
531        output from "man perlunicode" includes this:
533          The regular expression compiler produces polymorphic opcodes.  That
534          is, the pattern adapts to the data and automatically switches to
535          the Unicode character scheme when presented with Unicode data--or
536          instead uses a traditional byte scheme when presented with byte
537          data.
539        Sadly, a wide octal escape does not cause a switch, and in a string with
540        no other multibyte characters, these octal escapes are treated as before.
541        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
542        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
543        Unicode string.
545        I have not perpetrated such confusion in PCRE. Up till now, it took just
546        the bottom 8 bits, as in old Perl. I have now made octal escapes with
547        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
548        translate to the appropriate multibyte character.
550    29. Applied some refactoring to reduce the number of warnings from Microsoft
551        and Borland compilers. This has included removing the fudge introduced
552        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
553        a warning about an unused variable.
555    21. PCRE has not included VT (character 0x0b) in the set of whitespace
556        characters since release 4.0, because Perl (from release 5.004) does not.
557        [Or at least, is documented not to: some releases seem to be in conflict
558        with the documentation.] However, when a pattern was studied with
559        pcre_study() and all its branches started with \s, PCRE still included VT
560        as a possible starting character. Of course, this did no harm; it just
561        caused an unnecessary match attempt.
563    22. Removed a now-redundant internal flag bit that recorded the fact that case
564        dependency changed within the pattern. This was once needed for "required
565        byte" processing, but is no longer used. This recovers a now-scarce options
566        bit. Also moved the least significant internal flag bit to the most-
567        significant bit of the word, which was not previously used (hangover from
568        the days when it was an int rather than a uint) to free up another bit for
569        the future.
571    23. Added support for CRLF line endings as well as CR and LF. As well as the
572        default being selectable at build time, it can now be changed at runtime
573        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
574        specify that it is scanning data with non-default line endings.
576    24. Changed the definition of CXXLINK to make it agree with the definition of
577        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
579    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
580        recursions. This makes a big different to stack usage for some patterns.
582    26. If a subpattern containing a named recursion or subroutine reference such
583        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
584        the space required for the compiled pattern went wrong and gave too small a
585        value. Depending on the environment, this could lead to "Failed: internal
586        error: code overflow at offset 49" or "glibc detected double free or
587        corruption" errors.
589    27. Applied patches from Google (a) to support the new newline modes and (b) to
590        advance over multibyte UTF-8 characters in GlobalReplace.
592    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
593        difference for some implementation of PCRE in some Windows version.
595    29. Added some extra testing facilities to pcretest:
597        \q<number>   in a data line sets the "match limit" value
598        \Q<number>   in a data line sets the "match recursion limt" value
599        -S <number>  sets the stack size, where <number> is in megabytes
601        The -S option isn't available for Windows.
604    Version 6.6 06-Feb-06
605    ---------------------
607     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
608        in pcreposix.h. I have copied the definition from pcre.h.
610     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
611        because pcre.h is no longer a built file.
613     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
614        not normally included in the compiled code.
617    Version 6.5 01-Feb-06
618    ---------------------
620     1. When using the partial match feature with pcre_dfa_exec(), it was not
621        anchoring the second and subsequent partial matches at the new starting
622        point. This could lead to incorrect results. For example, with the pattern
623        /1234/, partially matching against "123" and then "a4" gave a match.
625     2. Changes to pcregrep:
627        (a) All non-match returns from pcre_exec() were being treated as failures
628            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
629            error message is output. Some extra information is given for the
630            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
631            probably the only errors that are likely to be caused by users (by
632            specifying a regex that has nested indefinite repeats, for instance).
633            If there are more than 20 of these errors, pcregrep is abandoned.
635        (b) A binary zero was treated as data while matching, but terminated the
636            output line if it was written out. This has been fixed: binary zeroes
637            are now no different to any other data bytes.
639        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
640            used to set a locale for matching. The --locale=xxxx long option has
641            been added (no short equivalent) to specify a locale explicitly on the
642            pcregrep command, overriding the environment variables.
644        (d) When -B was used with -n, some line numbers in the output were one less
645            than they should have been.
647        (e) Added the -o (--only-matching) option.
649        (f) If -A or -C was used with -c (count only), some lines of context were
650            accidentally printed for the final match.
652        (g) Added the -H (--with-filename) option.
654        (h) The combination of options -rh failed to suppress file names for files
655            that were found from directory arguments.
657        (i) Added the -D (--devices) and -d (--directories) options.
659        (j) Added the -F (--fixed-strings) option.
661        (k) Allow "-" to be used as a file name for -f as well as for a data file.
663        (l) Added the --colo(u)r option.
665        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
666            is not present by default.
668     3. A nasty bug was discovered in the handling of recursive patterns, that is,
669        items such as (?R) or (?1), when the recursion could match a number of
670        alternatives. If it matched one of the alternatives, but subsequently,
671        outside the recursion, there was a failure, the code tried to back up into
672        the recursion. However, because of the way PCRE is implemented, this is not
673        possible, and the result was an incorrect result from the match.
675        In order to prevent this happening, the specification of recursion has
676        been changed so that all such subpatterns are automatically treated as
677        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
679     4. I had overlooked the fact that, in some locales, there are characters for
680        which isalpha() is true but neither isupper() nor islower() are true. In
681        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
682        and ordfeminine) are like this. This affected the treatment of \w and \W
683        when they appeared in character classes, but not when they appeared outside
684        a character class. The bit map for "word" characters is now created
685        separately from the results of isalnum() instead of just taking it from the
686        upper, lower, and digit maps. (Plus the underscore character, of course.)
688     5. The above bug also affected the handling of POSIX character classes such as
689        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
690        permanent tables. Instead, the bit maps for such a class were previously
691        created as the appropriate unions of the upper, lower, and digit bitmaps.
692        Now they are created by subtraction from the [[:word:]] class, which has
693        its own bitmap.
695     6. The [[:blank:]] character class matches horizontal, but not vertical space.
696        It is created by subtracting the vertical space characters (\x09, \x0a,
697        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
698        subtraction was done in the overall bitmap for a character class, meaning
699        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
700        be recognized. This bug has been fixed.
702     7. Patches from the folks at Google:
704          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
705          real life, but is still worth protecting against".
707          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
708          regular expressions".
710          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
711          have it.
713          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
714          "configure" and the latter not, in order to fix a problem somebody had
715          with compiling the Arg class on HP-UX.
717          (e) Improve the error-handling of the C++ wrapper a little bit.
719          (f) New tests for checking recursion limiting.
721     8. The pcre_memmove() function, which is used only if the environment does not
722        have a standard memmove() function (and is therefore rarely compiled),
723        contained two bugs: (a) use of int instead of size_t, and (b) it was not
724        returning a result (though PCRE never actually uses the result).
726     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
727        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
728        returned instead of calling malloc() with an overflowing number that would
729        most likely cause subsequent chaos.
731    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
733    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
734        with this option is matched, the nmatch and pmatch options of regexec() are
735        ignored.
737    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
738        provided in case anyone wants to the the POSIX interface with UTF-8
739        strings.
741    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
742        C++ linking (needed for some HP-UX environments).
744    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
745        (unused parameter) and in the pcre_printint() function (omitted "default"
746        switch label when the default is to do nothing).
748    15. Added some code to make it possible, when PCRE is compiled as a C++
749        library, to replace subject pointers for pcre_exec() with a smart pointer
750        class, thus making it possible to process discontinuous strings.
752    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
753        much the same function. They were added by different people who were trying
754        to make PCRE easy to compile on non-Unix systems. It has been suggested
755        that PCRE_EXPORT be abolished now that there is more automatic apparatus
756        for compiling on Windows systems. I have therefore replaced it with
757        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
758        defaults to "extern" for C or "extern C" for C++, which works fine on
759        Unix-like systems. It is now possible to override the value of PCRE_DATA_
760        SCOPE with something explicit in config.h. In addition:
762        (a) pcreposix.h still had just "extern" instead of either of these macros;
763            I have replaced it with PCRE_DATA_SCOPE.
765        (b) Functions such as _pcre_xclass(), which are internal to the library,
766            but external in the C sense, all had PCRE_EXPORT in their definitions.
767            This is apparently wrong for the Windows case, so I have removed it.
768            (It makes no difference on Unix-like systems.)
770    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
771        of recursive calls to match(). This is different to MATCH_LIMIT because
772        that limits the total number of calls to match(), not all of which increase
773        the depth of recursion. Limiting the recursion depth limits the amount of
774        stack (or heap if NO_RECURSE is set) that is used. The default can be set
775        when PCRE is compiled, and changed at run time. A patch from Google adds
776        this functionality to the C++ interface.
778    18. Changes to the handling of Unicode character properties:
780        (a) Updated the table to Unicode 4.1.0.
782        (b) Recognize characters that are not in the table as "Cn" (undefined).
784        (c) I revised the way the table is implemented to a much improved format
785            which includes recognition of ranges. It now supports the ranges that
786            are defined in UnicodeData.txt, and it also amalgamates other
787            characters into ranges. This has reduced the number of entries in the
788            table from around 16,000 to around 3,000, thus reducing its size
789            considerably. I realized I did not need to use a tree structure after
790            all - a binary chop search is just as efficient. Having reduced the
791            number of entries, I extended their size from 6 bytes to 8 bytes to
792            allow for more data.
794        (d) Added support for Unicode script names via properties such as \p{Han}.
796    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
797        matching that character.
799    20. When matching a repeated Unicode property with a minimum greater than zero,
800        (for example \pL{2,}), PCRE could look past the end of the subject if it
801        reached it while seeking the minimum number of characters. This could
802        happen only if some of the characters were more than one byte long, because
803        there is a check for at least the minimum number of bytes.
805    21. Refactored the implementation of \p and \P so as to be more general, to
806        allow for more different types of property in future. This has changed the
807        compiled form incompatibly. Anybody with saved compiled patterns that use
808        \p or \P will have to recompile them.
810    22. Added "Any" and "L&" to the supported property types.
812    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
813        but give a compile time error if the value is greater than 0xff.
815    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
816        accidentally not being installed or uninstalled.
818    25. The pcre.h file was built from pcre.h.in, but the only changes that were
819        made were to insert the current release number. This seemed silly, because
820        it made things harder for people building PCRE on systems that don't run
821        "configure". I have turned pcre.h into a distributed file, no longer built
822        by "configure", with the version identification directly included. There is
823        no longer a pcre.h.in file.
825        However, this change necessitated a change to the pcre-config script as
826        well. It is built from pcre-config.in, and one of the substitutions was the
827        release number. I have updated configure.ac so that ./configure now finds
828        the release number by grepping pcre.h.
830    26. Added the ability to run the tests under valgrind.
833    Version 6.4 05-Sep-05
834    ---------------------
836     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
837        "--" to be printed when multiple files were scanned, even when none of the
838        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
839        consider it to be a bug, and have restored the previous behaviour.
841     2. A couple of code tidies to get rid of compiler warnings.
843     3. The pcretest program used to cheat by referring to symbols in the library
844        whose names begin with _pcre_. These are internal symbols that are not
845        really supposed to be visible externally, and in some environments it is
846        possible to suppress them. The cheating is now confined to including
847        certain files from the library's source, which is a bit cleaner.
849     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
850        file's purpose clearer.
852     5. Reorganized pcre_ucp_findchar().
855    Version 6.3 15-Aug-05
856    ---------------------
858     1. The file libpcre.pc.in did not have general read permission in the tarball.
860     2. There were some problems when building without C++ support:
862        (a) If C++ support was not built, "make install" and "make test" still
863            tried to test it.
865        (b) There were problems when the value of CXX was explicitly set. Some
866            changes have been made to try to fix these, and ...
868        (c) --disable-cpp can now be used to explicitly disable C++ support.
870        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
871            backslash in a target when C++ was disabled. This confuses some
872            versions of "make", apparently. Using an intermediate variable solves
873            this. (Same for CPP_LOBJ.)
875     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
876        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
877        necessary on certain architectures.
879     4. Added a setting of -export-symbols-regex to the link command to remove
880        those symbols that are exported in the C sense, but actually are local
881        within the library, and not documented. Their names all begin with
882        "_pcre_". This is not a perfect job, because (a) we have to except some
883        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
884        available (and never for static libraries). I have made a note to try to
885        find a way round (a) in the future.
888    Version 6.2 01-Aug-05
889    ---------------------
891     1. There was no test for integer overflow of quantifier values. A construction
892        such as {1111111111111111} would give undefined results. What is worse, if
893        a minimum quantifier for a parenthesized subpattern overflowed and became
894        negative, the calculation of the memory size went wrong. This could have
895        led to memory overwriting.
897     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
899     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
900        operating environments where this matters.
902     4. Applied Giuseppe Maxia's patch to add additional features for controlling
903        PCRE options from within the C++ wrapper.
905     5. Named capturing subpatterns were not being correctly counted when a pattern
906        was compiled. This caused two problems: (a) If there were more than 100
907        such subpatterns, the calculation of the memory needed for the whole
908        compiled pattern went wrong, leading to an overflow error. (b) Numerical
909        back references of the form \12, where the number was greater than 9, were
910        not recognized as back references, even though there were sufficient
911        previous subpatterns.
913     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
914        versions of gcc, e.g. 2.95.4.
917    Version 6.1 21-Jun-05
918    ---------------------
920     1. There was one reference to the variable "posix" in pcretest.c that was not
921        surrounded by "#if !defined NOPOSIX".
923     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
924        the cross-check on the old pcre_info() function, for the benefit of the
925        cut-down version of PCRE that is currently imported into Exim.
927     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
928        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
929        patterns that start (?i) but I don't think that matters. The use of (?i) is
930        just an example; this all applies to the other options as well.
932     4. Since libtool seems to echo the compile commands it is issuing, the output
933        from "make" can be reduced a bit by putting "@" in front of each libtool
934        compile command.
936     5. Patch from the folks at Google for configure.in to be a bit more thorough
937        in checking for a suitable C++ installation before trying to compile the
938        C++ stuff. This should fix a reported problem when a compiler was present,
939        but no suitable headers.
941     6. The man pages all had just "PCRE" as their title. I have changed them to
942        be the relevant file name. I have also arranged that these names are
943        retained in the file doc/pcre.txt, which is a concatenation in text format
944        of all the man pages except the little individual ones for each function.
946     7. The NON-UNIX-USE file had not been updated for the different set of source
947        files that come with release 6. I also added a few comments about the C++
948        wrapper.
951  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
952  ---------------------  ---------------------

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