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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 05-Jul-07
5    ---------------------
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
13          #include "pcre.h"
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
32     5. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp
33        unittest when running under MinGW.
35     6. ESC_K was left out of the EBCDIC table.
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
52    Version 7.2 19-Jun-07
53    ---------------------
55     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
56        which is apparently normally available under Windows.
58     2. Re-jig the pcregrep tests with different newline settings in an attempt
59        to make them independent of the local environment's newline setting.
61     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
63     4. Some of the "internals" tests were previously cut out when the link size
64        was not 2, because the output contained actual offsets. The recent new
65        "Z" feature of pcretest means that these can be cut out, making the tests
66        usable with all link sizes.
68     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
69        stack recursion. This gives a massive performance boost under BSD, but just
70        a small improvement under Linux. However, it saves one field in the frame
71        in all cases.
73     6. Added more features from the forthcoming Perl 5.10:
75        (a) (?-n) (where n is a string of digits) is a relative subroutine or
76            recursion call. It refers to the nth most recently opened parentheses.
78        (b) (?+n) is also a relative subroutine call; it refers to the nth next
79            to be opened parentheses.
81        (c) Conditions that refer to capturing parentheses can be specified
82            relatively, for example, (?(-2)... or (?(+3)...
84        (d) \K resets the start of the current match so that everything before
85            is not part of it.
87        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
89        (f) \g{name} is another synonym - part of Perl 5.10's unification of
90            reference syntax.
92        (g) (?| introduces a group in which the numbering of parentheses in each
93            alternative starts with the same number.
95        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
97     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
100     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
101        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
102        for detecting groups that can match an empty string.
104     9. A pattern with a very large number of alternatives (more than several
105        hundred) was running out of internal workspace during the pre-compile
106        phase, where pcre_compile() figures out how much memory will be needed. A
107        bit of new cunning has reduced the workspace needed for groups with
108        alternatives. The 1000-alternative test pattern now uses 12 bytes of
109        workspace instead of running out of the 4096 that are available.
111    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
113    11. Applied patch from Google to remove an optimization that didn't quite work.
114        The report of the bug said:
116          pcrecpp::RE("a*").FullMatch("aaa") matches, while
117          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
118          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
120    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
121        it matched the wrong number of bytes.
124    Version 7.1 24-Apr-07
125    ---------------------
127     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
128        that is more "standard", making use of automake and other Autotools. There
129        is some re-arrangement of the files and adjustment of comments consequent
130        on this.
132     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
133        for recursive directory scanning broke on some systems because the files
134        are not scanned in any specific order and on different systems the order
135        was different. A call to "sort" has been inserted into RunGrepTest for the
136        approprate test as a short-term fix. In the longer term there may be an
137        alternative.
139     3. I had an email from Eric Raymond about problems translating some of PCRE's
140        man pages to HTML (despite the fact that I distribute HTML pages, some
141        people do their own conversions for various reasons). The problems
142        concerned the use of low-level troff macros .br and .in. I have therefore
143        removed all such uses from the man pages (some were redundant, some could
144        be replaced by .nf/.fi pairs). The 132html script that I use to generate
145        HTML has been updated to handle .nf/.fi and to complain if it encounters
146        .br or .in.
148     4. Updated comments in configure.ac that get placed in config.h.in and also
149        arranged for config.h to be included in the distribution, with the name
150        config.h.generic, for the benefit of those who have to compile without
151        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
153     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
154        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
155        makevp.bat for the current PCRE, using the additional files
156        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
158     6. A Windows user reported a minor discrepancy with test 2, which turned out
159        to be caused by a trailing space on an input line that had got lost in his
160        copy. The trailing space was an accident, so I've just removed it.
162     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
163        that is needed.
165     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
166        as "const" (a) because they are and (b) because it helps the PHP
167        maintainers who have recently made a script to detect big data structures
168        in the php code that should be moved to the .rodata section. I remembered
169        to update Builducptable as well, so it won't revert if ucptable.h is ever
170        re-created.
172     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
173        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
174        order to be able to cut out the UTF-8 tables in the latter when UTF-8
175        support is not required. This saves 1.5-2K of code, which is important in
176        some applications.
178        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
179        so as not to refer to the tables, even though these functions will never be
180        called when UTF-8 support is disabled. Otherwise there are problems with a
181        shared library.
183    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
185        (a) It was defining its arguments as char * instead of void *.
187        (b) It was assuming that all moves were upwards in memory; this was true
188            a long time ago when I wrote it, but is no longer the case.
190        The emulated memove() is provided for those environments that have neither
191        memmove() nor bcopy(). I didn't think anyone used it these days, but that
192        is clearly not the case, as these two bugs were recently reported.
194    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
195        and Detrail to create the HTML documentation, the .txt form of the man
196        pages, and it removes trailing spaces from listed files. It also creates
197        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
198        case, it wraps all the #defines with #ifndefs. This script should be run
199        before "make dist".
201    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
202        with Unicode property support.
204        (a) For a maximizing quantifier, if the two different cases of the
205            character were of different lengths in their UTF-8 codings (there are
206            some cases like this - I found 11), and the matching function had to
207            back up over a mixture of the two cases, it incorrectly assumed they
208            were both the same length.
210        (b) When PCRE was configured to use the heap rather than the stack for
211            recursion during matching, it was not correctly preserving the data for
212            the other case of a UTF-8 character when checking ahead for a match
213            while processing a minimizing repeat. If the check also involved
214            matching a wide character, but failed, corruption could cause an
215            erroneous result when trying to check for a repeat of the original
216            character.
218    13. Some tidying changes to the testing mechanism:
220        (a) The RunTest script now detects the internal link size and whether there
221            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
222            values substituted by "configure". (The RunGrepTest script already did
223            this for UTF-8.) The configure.ac script no longer substitutes the
224            relevant variables.
226        (b) The debugging options /B and /D in pcretest show the compiled bytecode
227            with length and offset values. This means that the output is different
228            for different internal link sizes. Test 2 is skipped for link sizes
229            other than 2 because of this, bypassing the problem. Unfortunately,
230            there was also a test in test 3 (the locale tests) that used /B and
231            failed for link sizes other than 2. Rather than cut the whole test out,
232            I have added a new /Z option to pcretest that replaces the length and
233            offset values with spaces. This is now used to make test 3 independent
234            of link size. (Test 2 will be tidied up later.)
236    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
237        segmentation fault instead of returning the appropriate error message.
239    15. In multiline mode when the newline sequence was set to "any", the pattern
240        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
241        This doesn't seem right; it now treats the CRLF combination as the line
242        ending, and so does not match in that case. It's only a pattern such as ^$
243        that would hit this one: something like ^ABC$ would have failed after \r
244        and then tried again after \r\n.
246    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
247        in an attempt to make files that differ only in their line terminators
248        compare equal. This works on Linux.
250    17. Under certain error circumstances pcregrep might try to free random memory
251        as it exited. This is now fixed, thanks to valgrind.
253    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
254        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
255        was because its rules for how to advance for /g after matching an empty
256        string at the end of a line did not allow for this case. They now check for
257        it specially.
259    20. pcretest is supposed to handle patterns and data of any length, by
260        extending its buffers when necessary. It was getting this wrong when the
261        buffer for a data line had to be extended.
263    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
264        CRLF as a newline sequence.
266    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
267        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
268        I have nevertheless tidied it up.
270    23. Added some casts to kill warnings from HP-UX ia64 compiler.
272    24. Added a man page for pcre-config.
275    Version 7.0 19-Dec-06
276    ---------------------
278     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
279        moving to gcc 4.1.1.
281     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
282        sys/time.h, which is documented as needed for this function. It doesn't
283        seem to matter on Linux, but it showed up on some releases of OS X.
285     3. It seems that there are systems where bytes whose values are greater than
286        127 match isprint() in the "C" locale. The "C" locale should be the
287        default when a C program starts up. In most systems, only ASCII printing
288        characters match isprint(). This difference caused the output from pcretest
289        to vary, making some of the tests fail. I have changed pcretest so that:
291        (a) When it is outputting text in the compiled version of a pattern, bytes
292            other than 32-126 are always shown as hex escapes.
294        (b) When it is outputting text that is a matched part of a subject string,
295            it does the same, unless a different locale has been set for the match
296            (using the /L modifier). In this case, it uses isprint() to decide.
298     4. Fixed a major bug that caused incorrect computation of the amount of memory
299        required for a compiled pattern when options that changed within the
300        pattern affected the logic of the preliminary scan that determines the
301        length. The relevant options are -x, and -i in UTF-8 mode. The result was
302        that the computed length was too small. The symptoms of this bug were
303        either the PCRE error "internal error: code overflow" from pcre_compile(),
304        or a glibc crash with a message such as "pcretest: free(): invalid next
305        size (fast)". Examples of patterns that provoked this bug (shown in
306        pcretest format) are:
308          /(?-x: )/x
309          /(?x)(?-x: \s*#\s*)/
310          /((?i)[\x{c0}])/8
311          /(?i:[\x{c0}])/8
313        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
314        is now done differently.
316     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
317        wrapper classes; (b) implement a new function in the C++ scanner that is
318        more efficient than the old way of doing things because it avoids levels of
319        recursion in the regex matching; (c) add a paragraph to the documentation
320        for the FullMatch() function.
322     6. The escape sequence \n was being treated as whatever was defined as
323        "newline". Not only was this contrary to the documentation, which states
324        that \n is character 10 (hex 0A), but it also went horribly wrong when
325        "newline" was defined as CRLF. This has been fixed.
327     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
328        was being set to -1 for the "end of line" case (supposedly a value that no
329        character can have). Though this value is never used (the check for end of
330        line is "zero bytes in current character"), it caused compiler complaints.
331        I've changed it to 0xffffffff.
333     8. In pcre_version.c, the version string was being built by a sequence of
334        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
335        string (as it is for production releases) called a macro with an empty
336        argument. The C standard says the result of this is undefined. The gcc
337        compiler treats it as an empty string (which was what was wanted) but it is
338        reported that Visual C gives an error. The source has been hacked around to
339        avoid this problem.
341     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
342        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
343        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
344        of them did).
346    10. Originally, pcretest opened its input and output without "b"; then I was
347        told that "b" was needed in some environments, so it was added for release
348        5.0 to both the input and output. (It makes no difference on Unix-like
349        systems.) Later I was told that it is wrong for the input on Windows. I've
350        now abstracted the modes into two macros, to make it easier to fiddle with
351        them, and removed "b" from the input mode under Windows.
353    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
355    12. Added -help and --help to pcretest as an official way of being reminded
356        of the options.
358    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
359        and pcrecpp.cc because they annoy compilers at high warning levels.
361    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
363    15. Fixed an occurrence of == in configure.ac that should have been = (shell
364        scripts are not C programs :-) and which was not noticed because it works
365        on Linux.
367    16. pcretest is supposed to handle any length of pattern and data line (as one
368        line or as a continued sequence of lines) by extending its input buffer if
369        necessary. This feature was broken for very long pattern lines, leading to
370        a string of junk being passed to pcre_compile() if the pattern was longer
371        than about 50K.
373    17. I have done a major re-factoring of the way pcre_compile() computes the
374        amount of memory needed for a compiled pattern. Previously, there was code
375        that made a preliminary scan of the pattern in order to do this. That was
376        OK when PCRE was new, but as the facilities have expanded, it has become
377        harder and harder to keep it in step with the real compile phase, and there
378        have been a number of bugs (see for example, 4 above). I have now found a
379        cunning way of running the real compile function in a "fake" mode that
380        enables it to compute how much memory it would need, while actually only
381        ever using a few hundred bytes of working memory and without too many
382        tests of the mode. This should make future maintenance and development
383        easier. A side effect of this work is that the limit of 200 on the nesting
384        depth of parentheses has been removed (though this was never a serious
385        limitation, I suspect). However, there is a downside: pcre_compile() now
386        runs more slowly than before (30% or more, depending on the pattern). I
387        hope this isn't a big issue. There is no effect on runtime performance.
389    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
390        newline (only possible for the last line of a file) and it was a
391        pattern that set a locale (followed by /Lsomething), pcretest crashed.
393    19. Added additional timing features to pcretest. (1) The -tm option now times
394        matching only, not compiling. (2) Both -t and -tm can be followed, as a
395        separate command line item, by a number that specifies the number of
396        repeats to use when timing. The default is 50000; this gives better
397        precision, but takes uncomfortably long for very large patterns.
399    20. Extended pcre_study() to be more clever in cases where a branch of a
400        subpattern has no definite first character. For example, (a*|b*)[cd] would
401        previously give no result from pcre_study(). Now it recognizes that the
402        first character must be a, b, c, or d.
404    21. There was an incorrect error "recursive call could loop indefinitely" if
405        a subpattern (or the entire pattern) that was being tested for matching an
406        empty string contained only one non-empty item after a nested subpattern.
407        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
408        incorrectly, because the \d was being skipped in the check.
410    22. The pcretest program now has a new pattern option /B and a command line
411        option -b, which is equivalent to adding /B to every pattern. This causes
412        it to show the compiled bytecode, without the additional information that
413        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
414        is the same as /B/I).
416    23. A new optimization is now able automatically to treat some sequences such
417        as a*b as a*+b. More specifically, if something simple (such as a character
418        or a simple class like \d) has an unlimited quantifier, and is followed by
419        something that cannot possibly match the quantified thing, the quantifier
420        is automatically "possessified".
422    24. A recursive reference to a subpattern whose number was greater than 39
423        went wrong under certain circumstances in UTF-8 mode. This bug could also
424        have affected the operation of pcre_study().
426    25. Realized that a little bit of performance could be had by replacing
427        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
429    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
431    27. Possessive quantifiers such as a++ were previously implemented by turning
432        them into atomic groups such as ($>a+). Now they have their own opcodes,
433        which improves performance. This includes the automatically created ones
434        from 23 above.
436    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
437        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
438        the first matched character to be a colon. This applied both to named and
439        numbered groups.
441    29. The ucpinternal.h header file was missing its idempotency #ifdef.
443    30. I was sent a "project" file called libpcre.a.dev which I understand makes
444        building PCRE on Windows easier, so I have included it in the distribution.
446    31. There is now a check in pcretest against a ridiculously large number being
447        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
448        loop, the loop is abandoned.
450    32. Forward references to subpatterns in conditions such as (?(2)...) where
451        subpattern 2 is defined later cause pcre_compile() to search forwards in
452        the pattern for the relevant set of parentheses. This search went wrong
453        when there were unescaped parentheses in a character class, parentheses
454        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
456    33. "Subroutine" calls and backreferences were previously restricted to
457        referencing subpatterns earlier in the regex. This restriction has now
458        been removed.
460    34. Added a number of extra features that are going to be in Perl 5.10. On the
461        whole, these are just syntactic alternatives for features that PCRE had
462        previously implemented using the Python syntax or my own invention. The
463        other formats are all retained for compatibility.
465        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
466            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
467            also .NET compatible.
469        (b) A recursion or subroutine call to a named group can now be defined as
470            (?&name) as well as (?P>name).
472        (c) A backreference to a named group can now be defined as \k<name> or
473            \k'name' as well as (?P=name). The new forms, as well as being in Perl
474            5.10, are also .NET compatible.
476        (d) A conditional reference to a named group can now use the syntax
477            (?(<name>) or (?('name') as well as (?(name).
479        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
480            groups (named and numbered) that are never evaluated inline, but can be
481            called as "subroutines" from elsewhere. In effect, the DEFINE condition
482            is always false. There may be only one alternative in such a group.
484        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
485            as the simple (?(R). The condition is true only if the most recent
486            recursion is that of the given number or name. It does not search out
487            through the entire recursion stack.
489        (g) The escape \gN or \g{N} has been added, where N is a positive or
490            negative number, specifying an absolute or relative reference.
492    35. Tidied to get rid of some further signed/unsigned compiler warnings and
493        some "unreachable code" warnings.
495    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
496        things, this adds five new scripts.
498    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
499        There were also incompatibilities regarding the handling of \Q..\E inside
500        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
501        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
503    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
504        matches an empty string, and forcibly breaks the loop. There were bugs in
505        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
506        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
507        separate and independent bugs (that affected different cases) have been
508        fixed.
510    39. Refactored the code to abolish the use of different opcodes for small
511        capturing bracket numbers. This is a tidy that I avoided doing when I
512        removed the limit on the number of capturing brackets for 3.5 back in 2001.
513        The new approach is not only tidier, it makes it possible to reduce the
514        memory needed to fix the previous bug (38).
516    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
517        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
518        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
519        mode.
521    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
522        report.
524    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
525        copy construction and assignment in the C++ wrapper.
527    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
528        couple of bugs that could have given wrong results in the "--newline=crlf"
529        case.
531    44. Added a number of casts and did some reorganization of signed/unsigned int
532        variables following suggestions from Dair Grant. Also renamed the variable
533        "this" as "item" because it is a C++ keyword.
535    45. Arranged for dftables to add
537          #include "pcre_internal.h"
539        to pcre_chartables.c because without it, gcc 4.x may remove the array
540        definition from the final binary if PCRE is built into a static library and
541        dead code stripping is activated.
543    46. For an unanchored pattern, if a match attempt fails at the start of a
544        newline sequence, and the newline setting is CRLF or ANY, and the next two
545        characters are CRLF, advance by two characters instead of one.
548    Version 6.7 04-Jul-06
549    ---------------------
551     1. In order to handle tests when input lines are enormously long, pcretest has
552        been re-factored so that it automatically extends its buffers when
553        necessary. The code is crude, but this _is_ just a test program. The
554        default size has been increased from 32K to 50K.
556     2. The code in pcre_study() was using the value of the re argument before
557        testing it for NULL. (Of course, in any sensible call of the function, it
558        won't be NULL.)
560     3. The memmove() emulation function in pcre_internal.h, which is used on
561        systems that lack both memmove() and bcopy() - that is, hardly ever -
562        was missing a "static" storage class specifier.
564     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
565        containing an extended class (one that cannot be represented by a bitmap
566        because it contains high-valued characters or Unicode property items, e.g.
567        [\pZ]). Almost always one would set UTF-8 mode when processing such a
568        pattern, but PCRE should not loop if you do not (it no longer does).
569        [Detail: two cases were found: (a) a repeated subpattern containing an
570        extended class; (b) a recursive reference to a subpattern that followed a
571        previous extended class. It wasn't skipping over the extended class
572        correctly when UTF-8 mode was not set.]
574     5. A negated single-character class was not being recognized as fixed-length
575        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
576        compile error "lookbehind assertion is not fixed length".
578     6. The RunPerlTest auxiliary script was showing an unexpected difference
579        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
580        write a Perl script that can interpret lines of an input file either as
581        byte characters or as UTF-8, which is what "perltest" was being required to
582        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
583        can't do is switch easily at run time between having the "use utf8;" pragma
584        or not. In the end, I fudged it by using the RunPerlTest script to insert
585        "use utf8;" explicitly for the UTF-8 tests.
587     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
588        the end of the subject string, contrary to the documentation and to what
589        Perl does. This was true of both matching functions. Now it matches only at
590        the start of the subject and immediately after *internal* newlines.
592     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
593        a pointer to an int instead of a pointer to an unsigned long int. This
594        caused problems on 64-bit systems.
596     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
597        instance of the 'standard' template library not being so standard".
599    10. There was no check on the number of named subpatterns nor the maximum
600        length of a subpattern name. The product of these values is used to compute
601        the size of the memory block for a compiled pattern. By supplying a very
602        long subpattern name and a large number of named subpatterns, the size
603        computation could be caused to overflow. This is now prevented by limiting
604        the length of names to 32 characters, and the number of named subpatterns
605        to 10,000.
607    11. Subpatterns that are repeated with specific counts have to be replicated in
608        the compiled pattern. The size of memory for this was computed from the
609        length of the subpattern and the repeat count. The latter is limited to
610        65535, but there was no limit on the former, meaning that integer overflow
611        could in principle occur. The compiled length of a repeated subpattern is
612        now limited to 30,000 bytes in order to prevent this.
614    12. Added the optional facility to have named substrings with the same name.
616    13. Added the ability to use a named substring as a condition, using the
617        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
618        are numbers (not recommended). Forward references are permitted.
620    14. Added forward references in named backreferences (if you see what I mean).
622    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
623        pattern could run off the end of the subject. For example, the pattern
624        "(?s)(.{1,5})"8 did this with the subject "ab".
626    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
627        PCRE_CASELESS was set when matching characters that were quantified with ?
628        or *.
630    17. A character class other than a single negated character that had a minimum
631        but no maximum quantifier - for example [ab]{6,} - was not handled
632        correctly by pce_dfa_exec(). It would match only one character.
634    18. A valid (though odd) pattern that looked like a POSIX character
635        class but used an invalid character after [ (for example [[,abc,]]) caused
636        pcre_compile() to give the error "Failed: internal error: code overflow" or
637        in some cases to crash with a glibc free() error. This could even happen if
638        the pattern terminated after [[ but there just happened to be a sequence of
639        letters, a binary zero, and a closing ] in the memory that followed.
641    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
642        over the years. Originally (before any Unicode support), just the bottom 8
643        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
644        output from "man perlunicode" includes this:
646          The regular expression compiler produces polymorphic opcodes.  That
647          is, the pattern adapts to the data and automatically switches to
648          the Unicode character scheme when presented with Unicode data--or
649          instead uses a traditional byte scheme when presented with byte
650          data.
652        Sadly, a wide octal escape does not cause a switch, and in a string with
653        no other multibyte characters, these octal escapes are treated as before.
654        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
655        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
656        Unicode string.
658        I have not perpetrated such confusion in PCRE. Up till now, it took just
659        the bottom 8 bits, as in old Perl. I have now made octal escapes with
660        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
661        translate to the appropriate multibyte character.
663    29. Applied some refactoring to reduce the number of warnings from Microsoft
664        and Borland compilers. This has included removing the fudge introduced
665        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
666        a warning about an unused variable.
668    21. PCRE has not included VT (character 0x0b) in the set of whitespace
669        characters since release 4.0, because Perl (from release 5.004) does not.
670        [Or at least, is documented not to: some releases seem to be in conflict
671        with the documentation.] However, when a pattern was studied with
672        pcre_study() and all its branches started with \s, PCRE still included VT
673        as a possible starting character. Of course, this did no harm; it just
674        caused an unnecessary match attempt.
676    22. Removed a now-redundant internal flag bit that recorded the fact that case
677        dependency changed within the pattern. This was once needed for "required
678        byte" processing, but is no longer used. This recovers a now-scarce options
679        bit. Also moved the least significant internal flag bit to the most-
680        significant bit of the word, which was not previously used (hangover from
681        the days when it was an int rather than a uint) to free up another bit for
682        the future.
684    23. Added support for CRLF line endings as well as CR and LF. As well as the
685        default being selectable at build time, it can now be changed at runtime
686        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
687        specify that it is scanning data with non-default line endings.
689    24. Changed the definition of CXXLINK to make it agree with the definition of
690        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
692    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
693        recursions. This makes a big different to stack usage for some patterns.
695    26. If a subpattern containing a named recursion or subroutine reference such
696        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
697        the space required for the compiled pattern went wrong and gave too small a
698        value. Depending on the environment, this could lead to "Failed: internal
699        error: code overflow at offset 49" or "glibc detected double free or
700        corruption" errors.
702    27. Applied patches from Google (a) to support the new newline modes and (b) to
703        advance over multibyte UTF-8 characters in GlobalReplace.
705    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
706        difference for some implementation of PCRE in some Windows version.
708    29. Added some extra testing facilities to pcretest:
710        \q<number>   in a data line sets the "match limit" value
711        \Q<number>   in a data line sets the "match recursion limt" value
712        -S <number>  sets the stack size, where <number> is in megabytes
714        The -S option isn't available for Windows.
717    Version 6.6 06-Feb-06
718    ---------------------
720     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
721        in pcreposix.h. I have copied the definition from pcre.h.
723     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
724        because pcre.h is no longer a built file.
726     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
727        not normally included in the compiled code.
730    Version 6.5 01-Feb-06
731    ---------------------
733     1. When using the partial match feature with pcre_dfa_exec(), it was not
734        anchoring the second and subsequent partial matches at the new starting
735        point. This could lead to incorrect results. For example, with the pattern
736        /1234/, partially matching against "123" and then "a4" gave a match.
738     2. Changes to pcregrep:
740        (a) All non-match returns from pcre_exec() were being treated as failures
741            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
742            error message is output. Some extra information is given for the
743            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
744            probably the only errors that are likely to be caused by users (by
745            specifying a regex that has nested indefinite repeats, for instance).
746            If there are more than 20 of these errors, pcregrep is abandoned.
748        (b) A binary zero was treated as data while matching, but terminated the
749            output line if it was written out. This has been fixed: binary zeroes
750            are now no different to any other data bytes.
752        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
753            used to set a locale for matching. The --locale=xxxx long option has
754            been added (no short equivalent) to specify a locale explicitly on the
755            pcregrep command, overriding the environment variables.
757        (d) When -B was used with -n, some line numbers in the output were one less
758            than they should have been.
760        (e) Added the -o (--only-matching) option.
762        (f) If -A or -C was used with -c (count only), some lines of context were
763            accidentally printed for the final match.
765        (g) Added the -H (--with-filename) option.
767        (h) The combination of options -rh failed to suppress file names for files
768            that were found from directory arguments.
770        (i) Added the -D (--devices) and -d (--directories) options.
772        (j) Added the -F (--fixed-strings) option.
774        (k) Allow "-" to be used as a file name for -f as well as for a data file.
776        (l) Added the --colo(u)r option.
778        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
779            is not present by default.
781     3. A nasty bug was discovered in the handling of recursive patterns, that is,
782        items such as (?R) or (?1), when the recursion could match a number of
783        alternatives. If it matched one of the alternatives, but subsequently,
784        outside the recursion, there was a failure, the code tried to back up into
785        the recursion. However, because of the way PCRE is implemented, this is not
786        possible, and the result was an incorrect result from the match.
788        In order to prevent this happening, the specification of recursion has
789        been changed so that all such subpatterns are automatically treated as
790        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
792     4. I had overlooked the fact that, in some locales, there are characters for
793        which isalpha() is true but neither isupper() nor islower() are true. In
794        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
795        and ordfeminine) are like this. This affected the treatment of \w and \W
796        when they appeared in character classes, but not when they appeared outside
797        a character class. The bit map for "word" characters is now created
798        separately from the results of isalnum() instead of just taking it from the
799        upper, lower, and digit maps. (Plus the underscore character, of course.)
801     5. The above bug also affected the handling of POSIX character classes such as
802        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
803        permanent tables. Instead, the bit maps for such a class were previously
804        created as the appropriate unions of the upper, lower, and digit bitmaps.
805        Now they are created by subtraction from the [[:word:]] class, which has
806        its own bitmap.
808     6. The [[:blank:]] character class matches horizontal, but not vertical space.
809        It is created by subtracting the vertical space characters (\x09, \x0a,
810        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
811        subtraction was done in the overall bitmap for a character class, meaning
812        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
813        be recognized. This bug has been fixed.
815     7. Patches from the folks at Google:
817          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
818          real life, but is still worth protecting against".
820          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
821          regular expressions".
823          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
824          have it.
826          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
827          "configure" and the latter not, in order to fix a problem somebody had
828          with compiling the Arg class on HP-UX.
830          (e) Improve the error-handling of the C++ wrapper a little bit.
832          (f) New tests for checking recursion limiting.
834     8. The pcre_memmove() function, which is used only if the environment does not
835        have a standard memmove() function (and is therefore rarely compiled),
836        contained two bugs: (a) use of int instead of size_t, and (b) it was not
837        returning a result (though PCRE never actually uses the result).
839     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
840        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
841        returned instead of calling malloc() with an overflowing number that would
842        most likely cause subsequent chaos.
844    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
846    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
847        with this option is matched, the nmatch and pmatch options of regexec() are
848        ignored.
850    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
851        provided in case anyone wants to the the POSIX interface with UTF-8
852        strings.
854    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
855        C++ linking (needed for some HP-UX environments).
857    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
858        (unused parameter) and in the pcre_printint() function (omitted "default"
859        switch label when the default is to do nothing).
861    15. Added some code to make it possible, when PCRE is compiled as a C++
862        library, to replace subject pointers for pcre_exec() with a smart pointer
863        class, thus making it possible to process discontinuous strings.
865    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
866        much the same function. They were added by different people who were trying
867        to make PCRE easy to compile on non-Unix systems. It has been suggested
868        that PCRE_EXPORT be abolished now that there is more automatic apparatus
869        for compiling on Windows systems. I have therefore replaced it with
870        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
871        defaults to "extern" for C or "extern C" for C++, which works fine on
872        Unix-like systems. It is now possible to override the value of PCRE_DATA_
873        SCOPE with something explicit in config.h. In addition:
875        (a) pcreposix.h still had just "extern" instead of either of these macros;
876            I have replaced it with PCRE_DATA_SCOPE.
878        (b) Functions such as _pcre_xclass(), which are internal to the library,
879            but external in the C sense, all had PCRE_EXPORT in their definitions.
880            This is apparently wrong for the Windows case, so I have removed it.
881            (It makes no difference on Unix-like systems.)
883    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
884        of recursive calls to match(). This is different to MATCH_LIMIT because
885        that limits the total number of calls to match(), not all of which increase
886        the depth of recursion. Limiting the recursion depth limits the amount of
887        stack (or heap if NO_RECURSE is set) that is used. The default can be set
888        when PCRE is compiled, and changed at run time. A patch from Google adds
889        this functionality to the C++ interface.
891    18. Changes to the handling of Unicode character properties:
893        (a) Updated the table to Unicode 4.1.0.
895        (b) Recognize characters that are not in the table as "Cn" (undefined).
897        (c) I revised the way the table is implemented to a much improved format
898            which includes recognition of ranges. It now supports the ranges that
899            are defined in UnicodeData.txt, and it also amalgamates other
900            characters into ranges. This has reduced the number of entries in the
901            table from around 16,000 to around 3,000, thus reducing its size
902            considerably. I realized I did not need to use a tree structure after
903            all - a binary chop search is just as efficient. Having reduced the
904            number of entries, I extended their size from 6 bytes to 8 bytes to
905            allow for more data.
907        (d) Added support for Unicode script names via properties such as \p{Han}.
909    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
910        matching that character.
912    20. When matching a repeated Unicode property with a minimum greater than zero,
913        (for example \pL{2,}), PCRE could look past the end of the subject if it
914        reached it while seeking the minimum number of characters. This could
915        happen only if some of the characters were more than one byte long, because
916        there is a check for at least the minimum number of bytes.
918    21. Refactored the implementation of \p and \P so as to be more general, to
919        allow for more different types of property in future. This has changed the
920        compiled form incompatibly. Anybody with saved compiled patterns that use
921        \p or \P will have to recompile them.
923    22. Added "Any" and "L&" to the supported property types.
925    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
926        but give a compile time error if the value is greater than 0xff.
928    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
929        accidentally not being installed or uninstalled.
931    25. The pcre.h file was built from pcre.h.in, but the only changes that were
932        made were to insert the current release number. This seemed silly, because
933        it made things harder for people building PCRE on systems that don't run
934        "configure". I have turned pcre.h into a distributed file, no longer built
935        by "configure", with the version identification directly included. There is
936        no longer a pcre.h.in file.
938        However, this change necessitated a change to the pcre-config script as
939        well. It is built from pcre-config.in, and one of the substitutions was the
940        release number. I have updated configure.ac so that ./configure now finds
941        the release number by grepping pcre.h.
943    26. Added the ability to run the tests under valgrind.
946    Version 6.4 05-Sep-05
947    ---------------------
949     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
950        "--" to be printed when multiple files were scanned, even when none of the
951        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
952        consider it to be a bug, and have restored the previous behaviour.
954     2. A couple of code tidies to get rid of compiler warnings.
956     3. The pcretest program used to cheat by referring to symbols in the library
957        whose names begin with _pcre_. These are internal symbols that are not
958        really supposed to be visible externally, and in some environments it is
959        possible to suppress them. The cheating is now confined to including
960        certain files from the library's source, which is a bit cleaner.
962     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
963        file's purpose clearer.
965     5. Reorganized pcre_ucp_findchar().
968    Version 6.3 15-Aug-05
969    ---------------------
971     1. The file libpcre.pc.in did not have general read permission in the tarball.
973     2. There were some problems when building without C++ support:
975        (a) If C++ support was not built, "make install" and "make test" still
976            tried to test it.
978        (b) There were problems when the value of CXX was explicitly set. Some
979            changes have been made to try to fix these, and ...
981        (c) --disable-cpp can now be used to explicitly disable C++ support.
983        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
984            backslash in a target when C++ was disabled. This confuses some
985            versions of "make", apparently. Using an intermediate variable solves
986            this. (Same for CPP_LOBJ.)
988     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
989        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
990        necessary on certain architectures.
992     4. Added a setting of -export-symbols-regex to the link command to remove
993        those symbols that are exported in the C sense, but actually are local
994        within the library, and not documented. Their names all begin with
995        "_pcre_". This is not a perfect job, because (a) we have to except some
996        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
997        available (and never for static libraries). I have made a note to try to
998        find a way round (a) in the future.
1001    Version 6.2 01-Aug-05
1002    ---------------------
1004     1. There was no test for integer overflow of quantifier values. A construction
1005        such as {1111111111111111} would give undefined results. What is worse, if
1006        a minimum quantifier for a parenthesized subpattern overflowed and became
1007        negative, the calculation of the memory size went wrong. This could have
1008        led to memory overwriting.
1010     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1012     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1013        operating environments where this matters.
1015     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1016        PCRE options from within the C++ wrapper.
1018     5. Named capturing subpatterns were not being correctly counted when a pattern
1019        was compiled. This caused two problems: (a) If there were more than 100
1020        such subpatterns, the calculation of the memory needed for the whole
1021        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1022        back references of the form \12, where the number was greater than 9, were
1023        not recognized as back references, even though there were sufficient
1024        previous subpatterns.
1026     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1027        versions of gcc, e.g. 2.95.4.
1030    Version 6.1 21-Jun-05
1031    ---------------------
1033     1. There was one reference to the variable "posix" in pcretest.c that was not
1034        surrounded by "#if !defined NOPOSIX".
1036     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1037        the cross-check on the old pcre_info() function, for the benefit of the
1038        cut-down version of PCRE that is currently imported into Exim.
1040     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1041        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1042        patterns that start (?i) but I don't think that matters. The use of (?i) is
1043        just an example; this all applies to the other options as well.
1045     4. Since libtool seems to echo the compile commands it is issuing, the output
1046        from "make" can be reduced a bit by putting "@" in front of each libtool
1047        compile command.
1049     5. Patch from the folks at Google for configure.in to be a bit more thorough
1050        in checking for a suitable C++ installation before trying to compile the
1051        C++ stuff. This should fix a reported problem when a compiler was present,
1052        but no suitable headers.
1054     6. The man pages all had just "PCRE" as their title. I have changed them to
1055        be the relevant file name. I have also arranged that these names are
1056        retained in the file doc/pcre.txt, which is a concatenation in text format
1057        of all the man pages except the little individual ones for each function.
1059     7. The NON-UNIX-USE file had not been updated for the different set of source
1060        files that come with release 6. I also added a few comments about the C++
1061        wrapper.
1064    Version 6.0 07-Jun-05
1065    ---------------------
1067     1. Some minor internal re-organization to help with my DFA experiments.
1069     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1070        didn't matter for the library itself when fully configured, but did matter
1071        when compiling without UCP support, or within Exim, where the ucp files are
1072        not imported.
1074     3. Refactoring of the library code to split up the various functions into
1075        different source modules. The addition of the new DFA matching code (see
1076        below) to a single monolithic source would have made it really too
1077        unwieldy, quite apart from causing all the code to be include in a
1078        statically linked application, when only some functions are used. This is
1079        relevant even without the DFA addition now that patterns can be compiled in
1080        one application and matched in another.
1082        The downside of splitting up is that there have to be some external
1083        functions and data tables that are used internally in different modules of
1084        the library but which are not part of the API. These have all had their
1085        names changed to start with "_pcre_" so that they are unlikely to clash
1086        with other external names.
1088     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1089        a different (DFA) algorithm. Although it is slower than the original
1090        function, it does have some advantages for certain types of matching
1091        problem.
1093     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1094        including restarting after a partial match.
1096     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1097        defined when compiling for Windows was sent to me. I have put it into the
1098        code, though I have no means of testing or verifying it.
1100     7. Added the pcre_refcount() auxiliary function.
1102     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1103        match before or at the first newline in the subject string. In pcretest,
1104        the /f option on a pattern can be used to set this.
1106     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1107        would behave wrongly. This has been present in PCRE since release 4.0.
1109    10. A number of changes to the pcregrep command:
1111        (a) Refactored how -x works; insert ^(...)$ instead of setting
1112            PCRE_ANCHORED and checking the length, in preparation for adding
1113            something similar for -w.
1115        (b) Added the -w (match as a word) option.
1117        (c) Refactored the way lines are read and buffered so as to have more
1118            than one at a time available.
1120        (d) Implemented a pcregrep test script.
1122        (e) Added the -M (multiline match) option. This allows patterns to match
1123            over several lines of the subject. The buffering ensures that at least
1124            8K, or the rest of the document (whichever is the shorter) is available
1125            for matching (and similarly the previous 8K for lookbehind assertions).
1127        (f) Changed the --help output so that it now says
1129              -w, --word-regex(p)
1131            instead of two lines, one with "regex" and the other with "regexp"
1132            because that confused at least one person since the short forms are the
1133            same. (This required a bit of code, as the output is generated
1134            automatically from a table. It wasn't just a text change.)
1136        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1137            option but starts with a hyphen. Could be a pattern or a path name
1138            starting with a hyphen, for instance.
1140        (h) "-" can be given as a file name to represent stdin.
1142        (i) When file names are being printed, "(standard input)" is used for
1143            the standard input, for compatibility with GNU grep. Previously
1144            "<stdin>" was used.
1146        (j) The option --label=xxx can be used to supply a name to be used for
1147            stdin when file names are being printed. There is no short form.
1149        (k) Re-factored the options decoding logic because we are going to add
1150            two more options that take data. Such options can now be given in four
1151            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1153        (l) Added the -A, -B, and -C options for requesting that lines of context
1154            around matches be printed.
1156        (m) Added the -L option to print the names of files that do not contain
1157            any matching lines, that is, the complement of -l.
1159        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1160            continue to scan other files.
1162        (o) The -s option was incorrectly implemented. For compatibility with other
1163            greps, it now suppresses the error message for a non-existent or non-
1164            accessible file (but not the return code). There is a new option called
1165            -q that suppresses the output of matching lines, which was what -s was
1166            previously doing.
1168        (p) Added --include and --exclude options to specify files for inclusion
1169            and exclusion when recursing.
1171    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1172        Hopefully, it now does.
1174    12. Missing cast in pcre_study().
1176    13. Added an "uninstall" target to the makefile.
1178    14. Replaced "extern" in the function prototypes in Makefile.in with
1179        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1180        world, but is set differently for Windows.
1182    15. Added a second compiling function called pcre_compile2(). The only
1183        difference is that it has an extra argument, which is a pointer to an
1184        integer error code. When there is a compile-time failure, this is set
1185        non-zero, in addition to the error test pointer being set to point to an
1186        error message. The new argument may be NULL if no error number is required
1187        (but then you may as well call pcre_compile(), which is now just a
1188        wrapper). This facility is provided because some applications need a
1189        numeric error indication, but it has also enabled me to tidy up the way
1190        compile-time errors are handled in the POSIX wrapper.
1192    16. Added VPATH=.libs to the makefile; this should help when building with one
1193        prefix path and installing with another. (Or so I'm told by someone who
1194        knows more about this stuff than I do.)
1196    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1197        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1198        match everything, including newlines. This is not POSIX-compatible, but
1199        somebody wanted the feature. From pcretest it can be activated by using
1200        both the P and the s flags.
1202    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1204    19. libpcre.pc was being incorrectly installed as executable.
1206    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1207        it now also looks for '\r' so that it will work unmodified on Windows.
1209    21. Added Google's contributed C++ wrapper to the distribution.
1211    22. Added some untidy missing memory free() calls in pcretest, to keep
1212        Electric Fence happy when testing.
1216    Version 5.0 13-Sep-04
1217    ---------------------
1219     1. Internal change: literal characters are no longer packed up into items
1220        containing multiple characters in a single byte-string. Each character
1221        is now matched using a separate opcode. However, there may be more than one
1222        byte in the character in UTF-8 mode.
1224     2. The pcre_callout_block structure has two new fields: pattern_position and
1225        next_item_length. These contain the offset in the pattern to the next match
1226        item, and its length, respectively.
1228     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1229        insertion of callouts before each pattern item. Added the /C option to
1230        pcretest to make use of this.
1232     4. On the advice of a Windows user, the lines
1234          #if defined(_WIN32) || defined(WIN32)
1235          _setmode( _fileno( stdout ), 0x8000 );
1236          #endif  /* defined(_WIN32) || defined(WIN32) */
1238        have been added to the source of pcretest. This apparently does useful
1239        magic in relation to line terminators.
1241     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1242        for the benefit of those environments where the "b" makes a difference.
1244     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1245        to know about it. I have put a hack into configure.in that adds in code
1246        to set GCC=yes if CC=icc. This seems to end up at a point in the
1247        generated configure script that is early enough to affect the setting of
1248        compiler options, which is what is needed, but I have no means of testing
1249        whether it really works. (The user who reported this had patched the
1250        generated configure script, which of course I cannot do.)
1252        LATER: After change 22 below (new libtool files), the configure script
1253        seems to know about icc (and also ecc). Therefore, I have commented out
1254        this hack in configure.in.
1256     7. Added support for pkg-config (2 patches were sent in).
1258     8. Negated POSIX character classes that used a combination of internal tables
1259        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1260        [[:^ascii]]. Typically, they would match almost any characters. The other
1261        POSIX classes were not broken in this way.
1263     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1264        to find the match, as PCRE was deluded into thinking that the match had to
1265        start at the start point or following a newline. The same bug applied to
1266        patterns with negative forward assertions or any backward assertions
1267        preceding ".*" at the start, unless the pattern required a fixed first
1268        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1270    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1271        starting at the last subject character, bytes beyond the end of the subject
1272        string were read.
1274    11. Renamed the variable "class" as "classbits" to make life easier for C++
1275        users. (Previously there was a macro definition, but it apparently wasn't
1276        enough.)
1278    12. Added the new field "tables" to the extra data so that tables can be passed
1279        in at exec time, or the internal tables can be re-selected. This allows
1280        a compiled regex to be saved and re-used at a later time by a different
1281        program that might have everything at different addresses.
1283    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1284        -R library as well as a -L library.
1286    14. The debugging options of pcretest (-d on the command line or D on a
1287        pattern) showed incorrect output for anything following an extended class
1288        that contained multibyte characters and which was followed by a quantifier.
1290    15. Added optional support for general category Unicode character properties
1291        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1292        support. It adds about 90K to the size of the library. The meanings of the
1293        inbuilt class escapes such as \d and \s have NOT been changed.
1295    16. Updated pcredemo.c to include calls to free() to release the memory for the
1296        compiled pattern.
1298    17. The generated file chartables.c was being created in the source directory
1299        instead of in the building directory. This caused the build to fail if the
1300        source directory was different from the building directory, and was
1301        read-only.
1303    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1304        file. No doubt somebody will tell me if they don't make sense... Also added
1305        Dan Mooney's comments about building on OpenVMS.
1307    19. Added support for partial matching via the PCRE_PARTIAL option for
1308        pcre_exec() and the \P data escape in pcretest.
1310    20. Extended pcretest with 3 new pattern features:
1312        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1313              write the compiled pattern to the file whose name is "rest-of-line".
1314              This is a straight binary dump of the data, with the saved pointer to
1315              the character tables forced to be NULL. The study data, if any, is
1316              written too. After writing, pcretest reads a new pattern.
1318        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1319              compiled pattern from the given file. There must not be any
1320              occurrences of "<" in the file name (pretty unlikely); if there are,
1321              pcretest will instead treat the initial "<" as a pattern delimiter.
1322              After reading in the pattern, pcretest goes on to read data lines as
1323              usual.
1325        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1326              and 16-bit fields in a compiled pattern, to simulate a pattern that
1327              was compiled on a host of opposite endianness.
1329    21. The pcre-exec() function can now cope with patterns that were compiled on
1330        hosts of opposite endianness, with this restriction:
1332          As for any compiled expression that is saved and used later, the tables
1333          pointer field cannot be preserved; the extra_data field in the arguments
1334          to pcre_exec() should be used to pass in a tables address if a value
1335          other than the default internal tables were used at compile time.
1337    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1338        now diagnosed as an error. Previously, most of the time, a negative number
1339        would have been treated as zero, but if in addition "ovector" was passed as
1340        NULL, a crash could occur.
1342    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1343        new versions from the libtool 1.5 distribution (the last one is a copy of
1344        a file called libtool.m4). This seems to have fixed the need to patch
1345        "configure" to support Darwin 1.3 (which I used to do). However, I still
1346        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1347        workstation).
1349    24. Changed the PCRE licence to be the more standard "BSD" licence.
1352    Version 4.5 01-Dec-03
1353    ---------------------
1355     1. There has been some re-arrangement of the code for the match() function so
1356        that it can be compiled in a version that does not call itself recursively.
1357        Instead, it keeps those local variables that need separate instances for
1358        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1359        needs to "recurse". Keeping track of where control must go is done by means
1360        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1361        hide most of the details from the main code, and operates only if
1362        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1363        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1364        operating.
1366        To make it easier for callers to provide specially tailored get/free
1367        functions for this usage, two new functions, pcre_stack_malloc, and
1368        pcre_stack_free, are used. They are always called in strict stacking order,
1369        and the size of block requested is always the same.
1371        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1372        PCRE has been compiled to use the stack or the heap for recursion. The
1373        -C option of pcretest uses this to show which version is compiled.
1375        A new data escape \S, is added to pcretest; it causes the amounts of store
1376        obtained and freed by both kinds of malloc/free at match time to be added
1377        to the output.
1379     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1380        what's available on my current Linux desktop machine.
1382     3. When matching a UTF-8 string, the test for a valid string at the start has
1383        been extended. If start_offset is not zero, PCRE now checks that it points
1384        to a byte that is the start of a UTF-8 character. If not, it returns
1385        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1386        this is necessary because there may be backward assertions in the pattern.
1387        When matching the same subject several times, it may save resources to use
1388        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1390     4. The code for checking the validity of UTF-8 strings has been tightened so
1391        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1392        containing "overlong sequences".
1394     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1395        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1396        should have been "&", but it just so happened that all the cases this let
1397        through by mistake were picked up later in the function.
1399     6. I had used a variable called "isblank" - this is a C99 function, causing
1400        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1402     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1403        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1404        so the version is shown; (c) stop "make test" echoing "./RunTest".
1406     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1408     9. The prototype for memmove() for systems that don't have it was using
1409        size_t, but the inclusion of the header that defines size_t was later. I've
1410        moved the #includes for the C headers earlier to avoid this.
1412    10. Added some adjustments to the code to make it easier to compiler on certain
1413        special systems:
1415          (a) Some "const" qualifiers were missing.
1416          (b) Added the macro EXPORT before all exported functions; by default this
1417              is defined to be empty.
1418          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1419              that it reads its output file name as an argument instead of writing
1420              to the standard output and assuming this can be redirected.
1422    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1423        class containing characters with values greater than 255, PCRE compilation
1424        went into a loop.
1426    12. A recursive reference to a subpattern that was within another subpattern
1427        that had a minimum quantifier of zero caused PCRE to crash. For example,
1428        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1429        recursion. If the recursively-called subpattern itself had a zero repeat,
1430        that was OK.
1432    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1433        buffer into which it was copied (for escape processing) was still set at
1434        1024, so long lines caused crashes.
1436    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1437        "internal error: code overflow...". This applied to any character class
1438        that was followed by a possessive quantifier.
1440    15. Modified the Makefile to add libpcre.la as a prerequisite for
1441        libpcreposix.la because I was told this is needed for a parallel build to
1442        work.
1444    16. If a pattern that contained .* following optional items at the start was
1445        studied, the wrong optimizing data was generated, leading to matching
1446        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1447        matching string must start with a or b or c. The correct conclusion for
1448        this pattern is that a match can start with any character.
1451    Version 4.4 13-Aug-03
1452    ---------------------
1454     1. In UTF-8 mode, a character class containing characters with values between
1455        127 and 255 was not handled correctly if the compiled pattern was studied.
1456        In fixing this, I have also improved the studying algorithm for such
1457        classes (slightly).
1459     2. Three internal functions had redundant arguments passed to them. Removal
1460        might give a very teeny performance improvement.
1462     3. Documentation bug: the value of the capture_top field in a callout is *one
1463        more than* the number of the hightest numbered captured substring.
1465     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1466        in incorrectly linking with a previously installed version. They now link
1467        explicitly with libpcre.la.
1469     5. configure.in no longer needs to recognize Cygwin specially.
1471     6. A problem in pcre.in for Windows platforms is fixed.
1473     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1474        pcretest, it used to include the size of the study block as part of its
1475        output. Unfortunately, the structure contains a field that has a different
1476        size on different hardware architectures. This meant that the tests that
1477        showed this size failed. As the block is currently always of a fixed size,
1478        this information isn't actually particularly useful in pcretest output, so
1479        I have just removed it.
1481     8. Three pre-processor statements accidentally did not start in column 1.
1482        Sadly, there are *still* compilers around that complain, even though
1483        standard C has not required this for well over a decade. Sigh.
1485     9. In pcretest, the code for checking callouts passed small integers in the
1486        callout_data field, which is a void * field. However, some picky compilers
1487        complained about the casts involved for this on 64-bit systems. Now
1488        pcretest passes the address of the small integer instead, which should get
1489        rid of the warnings.
1491    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1492        both compile and run time, and gives an error if an invalid UTF-8 sequence
1493        is found. There is a option for disabling this check in cases where the
1494        string is known to be correct and/or the maximum performance is wanted.
1496    11. In response to a bug report, I changed one line in Makefile.in from
1498            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1499        to
1500            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1502        to look similar to other lines, but I have no way of telling whether this
1503        is the right thing to do, as I do not use Windows. No doubt I'll get told
1504        if it's wrong...
1507    Version 4.3 21-May-03
1508    ---------------------
1510    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1511       Makefile.
1513    2. Some refactoring to improve the quality of the code:
1515       (i)   The utf8_table... variables are now declared "const".
1517       (ii)  The code for \cx, which used the "case flipping" table to upper case
1518             lower case letters, now just substracts 32. This is ASCII-specific,
1519             but the whole concept of \cx is ASCII-specific, so it seems
1520             reasonable.
1522       (iii) PCRE was using its character types table to recognize decimal and
1523             hexadecimal digits in the pattern. This is silly, because it handles
1524             only 0-9, a-f, and A-F, but the character types table is locale-
1525             specific, which means strange things might happen. A private
1526             table is now used for this - though it costs 256 bytes, a table is
1527             much faster than multiple explicit tests. Of course, the standard
1528             character types table is still used for matching digits in subject
1529             strings against \d.
1531       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1532             ending in _t are). So I've renamed it as ESC_tee.
1534    3. The first argument for regexec() in the POSIX wrapper should have been
1535       defined as "const".
1537    4. Changed pcretest to use malloc() for its buffers so that they can be
1538       Electric Fenced for debugging.
1540    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1541       to read one or more bytes before the start of the subject string. Often this
1542       had no effect on PCRE's behaviour, but in some circumstances it could
1543       provoke a segmentation fault.
1545    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1546       to try to read one or more bytes before the start of the subject string.
1548    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1549       UTF-8 support could misbehave in various ways if the subject string
1550       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1551       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1552       back over UTF-8 characters.)
1555    Version 4.2 14-Apr-03
1556    ---------------------
1558    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1560    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1561         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1562         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1563         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1564         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1565           and BUILD_EXEEXT
1566         Note: automatic setting of the BUILD variables is not yet working
1567         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1568           compile-time but not at link-time
1569         [LINK]: use for linking executables only
1570         make different versions for Windows and non-Windows
1571         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1572           libraries
1573         [LINK_FOR_BUILD]: new variable
1574         [OBJEXT]: use throughout
1575         [EXEEXT]: use throughout
1576         <winshared>: new target
1577         <wininstall>: new target
1578         <dftables.o>: use native compiler
1579         <dftables>: use native linker
1580         <install>: handle Windows platform correctly
1581         <clean>: ditto
1582         <check>: ditto
1583         copy DLL to top builddir before testing
1585       As part of these changes, -no-undefined was removed again. This was reported
1586       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1587       in any case.
1589    3. Some tidies to get rid of compiler warnings:
1591       . In the match_data structure, match_limit was an unsigned long int, whereas
1592         match_call_count was an int. I've made them both unsigned long ints.
1594       . In pcretest the fact that a const uschar * doesn't automatically cast to
1595         a void * provoked a warning.
1597       . Turning on some more compiler warnings threw up some "shadow" variables
1598         and a few more missing casts.
1600    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1601       option, a class that contained a single character with a value between 128
1602       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1604    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1605       option, a class that contained several characters, but with at least one
1606       whose value was between 128 and 255 caused PCRE to crash.
1609    Version 4.1 12-Mar-03
1610    ---------------------
1612    1. Compiling with gcc -pedantic found a couple of places where casts were
1613    needed, and a string in dftables.c that was longer than standard compilers are
1614    required to support.
1616    2. Compiling with Sun's compiler found a few more places where the code could
1617    be tidied up in order to avoid warnings.
1619    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1620    first of these names is deprecated in the latest Autoconf in favour of the name
1621    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1622    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1623    analogy I have changed it to CFLAGS_FOR_BUILD.
1625    4. Added -no-undefined to the linking command in the Makefile, because this is
1626    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1627    linking step for the pcreposix library.
1629    5. PCRE was failing to diagnose the case of two named groups with the same
1630    name.
1632    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1633    literal character that is needed in the subject for a match, and scans along to
1634    ensure that it is present before embarking on the full matching process. This
1635    saves time in cases of nested unlimited repeats that are never going to match.
1636    Problem: the scan can take a lot of time if the subject is very long (e.g.
1637    megabytes), thus penalizing straightforward matches. It is now done only if the
1638    amount of subject to be scanned is less than 1000 bytes.
1640    7. A lesser problem with the same optimization is that it was recording the
1641    first character of an anchored pattern as "needed", thus provoking a search
1642    right along the subject, even when the first match of the pattern was going to
1643    fail. The "needed" character is now not set for anchored patterns, unless it
1644    follows something in the pattern that is of non-fixed length. Thus, it still
1645    fulfils its original purpose of finding quick non-matches in cases of nested
1646    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1649    Version 4.0 17-Feb-03
1650    ---------------------
1652    1. If a comment in an extended regex that started immediately after a meta-item
1653    extended to the end of string, PCRE compiled incorrect data. This could lead to
1654    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1656    2. Moved to autoconf 2.53 and libtool 1.4.2.
1658    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1659    the special perltest8 script is no longer needed - all the tests can be run
1660    from a single perltest script.
1662    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1663    by \s. It has now been removed in PCRE. This means it isn't recognized as
1664    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1665    class [:space:] *does* include VT, thereby creating a mess.
1667    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1668    space and tab.
1670    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1671    its new features into the main test script, reducing the number of scripts.
1673    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1674    were backward compatible, and made the (?i) apply to the whole pattern, as if
1675    /i were given. Now it behaves more logically, and applies the option setting
1676    only to what follows. PCRE has been changed to follow suit. However, if it
1677    finds options settings right at the start of the pattern, it extracts them into
1678    the global options, as before. Thus, they show up in the info data.
1680    8. Added support for the \Q...\E escape sequence. Characters in between are
1681    treated as literals. This is slightly different from Perl in that $ and @ are
1682    also handled as literals inside the quotes. In Perl, they will cause variable
1683    interpolation. Note the following examples:
1685        Pattern            PCRE matches      Perl matches
1687        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1688        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1689        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1691    For compatibility with Perl, \Q...\E sequences are recognized inside character
1692    classes as well as outside them.
1694    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1695    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1696    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1697    signed/unsigned warnings.
1699    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1700    option for pcretest, so I've replaced it by a simple function that does just
1701    that job.
1703    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1704    "pcregrep -".
1706    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1707    Java package. This provides some syntactic sugar for simple cases of what my
1708    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1709    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1710    item, you can use this simplified notation. Note that only makes sense with
1711    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1712    greediness, whatever the setting of the PCRE_UNGREEDY option.
1714    13. A change of greediness default within a pattern was not taking effect at
1715    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1716    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1717    was abstracted outside.
1719    14. PCRE now supports the \G assertion. It is true when the current matching
1720    position is at the start point of the match. This differs from \A when the
1721    starting offset is non-zero. Used with the /g option of pcretest (or similar
1722    code), it works in the same way as it does for Perl's /g option. If all
1723    alternatives of a regex begin with \G, the expression is anchored to the start
1724    match position, and the "anchored" flag is set in the compiled expression.
1726    15. Some bugs concerning the handling of certain option changes within patterns
1727    have been fixed. These applied to options other than (?ims). For example,
1728    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1729    been the other way round. Some of this was related to change 7 above.
1731    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1732    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1733    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1734    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1736    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1737    mode. Unlike ".", it always matches newline, whatever the setting of
1738    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1739    assertions. Perl allows it, but it doesn't (in general) work because it can't
1740    calculate the length of the lookbehind. At least, that's the case for Perl
1741    5.8.0 - I've been told they are going to document that it doesn't work in
1742    future.
1744    18. Added an error diagnosis for escapes that PCRE does not support: these are
1745    \L, \l, \N, \P, \p, \U, \u, and \X.
1747    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1748    reading past the end of the pattern in cases such as /[abcd/.
1750    20. PCRE was getting more memory than necessary for patterns with classes that
1751    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1753    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1754    compiling PCRE for use with Virtual Pascal.
1756    22. Small fix to the Makefile to make it work properly if the build is done
1757    outside the source tree.
1759    23. Added a new extension: a condition to go with recursion. If a conditional
1760    subpattern starts with (?(R) the "true" branch is used if recursion has
1761    happened, whereas the "false" branch is used only at the top level.
1763    24. When there was a very long string of literal characters (over 255 bytes
1764    without UTF support, over 250 bytes with UTF support), the computation of how
1765    much memory was required could be incorrect, leading to segfaults or other
1766    strange effects.
1768    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1769    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1770    there was a subsequent back reference to those brackets. This meant that, for
1771    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1772    possible to check for precisely this case. All we can do is abandon the
1773    optimization if .* occurs inside capturing brackets when there are any back
1774    references whatsoever. (See below for a better fix that came later.)
1776    26. The handling of the optimization for finding the first character of a
1777    non-anchored pattern, and for finding a character that is required later in the
1778    match were failing in some cases. This didn't break the matching; it just
1779    failed to optimize when it could. The way this is done has been re-implemented.
1781    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1783    28. Added a new feature that provides some of the functionality that Perl
1784    provides with (?{...}). The facility is termed a "callout". The way it is done
1785    in PCRE is for the caller to provide an optional function, by setting
1786    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1787    global variable. By default it is unset, which disables all calling out. To get
1788    the function called, the regex must include (?C) at appropriate points. This
1789    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1790    This provides a means of identifying different callout points. When PCRE
1791    reaches such a point in the regex, if pcre_callout has been set, the external
1792    function is called. It is provided with data in a structure called
1793    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1794    matching continues; if it returns a non-zero value, the match at the current
1795    point fails. However, backtracking will occur if possible. [This was changed
1796    later and other features added - see item 49 below.]
1798    29. pcretest is upgraded to test the callout functionality. It provides a
1799    callout function that displays information. By default, it shows the start of
1800    the match and the current position in the text. There are some new data escapes
1801    to vary what happens:
1803        \C+         in addition, show current contents of captured substrings
1804        \C-         do not supply a callout function
1805        \C!n        return 1 when callout number n is reached
1806        \C!n!m      return 1 when callout number n is reached for the mth time
1808    30. If pcregrep was called with the -l option and just a single file name, it
1809    output "<stdin>" if a match was found, instead of the file name.
1811    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1812    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1813    pcre_exec(). This saves a malloc/free per call. The default value of
1814    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1815    when configuring.
1817    32. The default maximum size of a compiled pattern is 64K. There have been a
1818    few cases of people hitting this limit. The code now uses macros to handle the
1819    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1820    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1821    configuring. Tests 2 and 5 work only with 2-byte links because they output
1822    debugging information about compiled patterns.
1824    33. Internal code re-arrangements:
1826    (a) Moved the debugging function for printing out a compiled regex into
1827        its own source file (printint.c) and used #include to pull it into
1828        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1829        separate copies.
1831    (b) Defined the list of op-code names for debugging as a macro in
1832        internal.h so that it is next to the definition of the opcodes.
1834    (c) Defined a table of op-code lengths for simpler skipping along compiled
1835        code. This is again a macro in internal.h so that it is next to the
1836        definition of the opcodes.
1838    34. Added support for recursive calls to individual subpatterns, along the
1839    lines of Robin Houston's patch (but implemented somewhat differently).
1841    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1842    allow it to read and process whole directories in Win32. This code was
1843    contributed by Lionel Fourquaux; it has not been tested by me.
1845    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1846    used to name a group. Names consist of alphanumerics and underscores, and must
1847    be unique. Back references use the syntax (?P=name) and recursive calls use
1848    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1849    numbers. The function pcre_fullinfo() can be used after compilation to extract
1850    a name/number map. There are three relevant calls:
1852      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1853      PCRE_INFO_NAMECOUNT            yields the number of entries
1854      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1856    The map is a vector of fixed-size entries. The size of each entry depends on
1857    the length of the longest name used. The first two bytes of each entry are the
1858    group number, most significant byte first. There follows the corresponding
1859    name, zero terminated. The names are in alphabetical order.
1861    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1862    case instead of 255. Making it the same both with and without UTF-8 support
1863    means that the same test output works with both.
1865    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1866    calling malloc() with a zero argument.
1868    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1869    optimization. I've improved things by keeping a bitmap of backreferences with
1870    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1871    fact referenced, the optimization can be applied. It is unlikely that a
1872    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1873    the match to follow \n) will appear inside brackets with a number greater than
1874    31, but if it does, any back reference > 31 suppresses the optimization.
1876    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1877    of disabling numbered capturing parentheses. Any opening parenthesis that is
1878    not followed by ? behaves as if it were followed by ?: but named parentheses
1879    can still be used for capturing (and they will acquire numbers in the usual
1880    way).
1882    41. Redesigned the return codes from the match() function into yes/no/error so
1883    that errors can be passed back from deep inside the nested calls. A malloc
1884    failure while inside a recursive subpattern call now causes the
1885    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1887    42. It is now possible to set a limit on the number of times the match()
1888    function is called in a call to pcre_exec(). This facility makes it possible to
1889    limit the amount of recursion and backtracking, though not in a directly
1890    obvious way, because the match() function is used in a number of different
1891    circumstances. The count starts from zero for each position in the subject
1892    string (for non-anchored patterns). The default limit is, for compatibility, a
1893    large number, namely 10 000 000. You can change this in two ways:
1895    (a) When configuring PCRE before making, you can use --with-match-limit=n
1896        to set a default value for the compiled library.
1898    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1899        a different value is set. See 45 below.
1901    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1903    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1904    of things that can be changed at compile time. The first argument specifies
1905    what is wanted and the second points to where the information is to be placed.
1906    The current list of available information is:
1908      PCRE_CONFIG_UTF8
1910    The output is an integer that is set to one if UTF-8 support is available;
1911    otherwise it is set to zero.
1915    The output is an integer that it set to the value of the code that is used for
1916    newline. It is either LF (10) or CR (13).
1920    The output is an integer that contains the number of bytes used for internal
1921    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1925    The output is an integer that contains the threshold above which the POSIX
1926    interface uses malloc() for output vectors. See item 31 above.
1930    The output is an unsigned integer that contains the default limit of the number
1931    of match() calls in a pcre_exec() execution. See 42 above.
1933    44. pcretest has been upgraded by the addition of the -C option. This causes it
1934    to extract all the available output from the new pcre_config() function, and to
1935    output it. The program then exits immediately.
1937    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1938    order to support additional features. One way would have been to define
1939    pcre_exec2() (for example) with extra arguments, but this would not have been
1940    extensible, and would also have required all calls to the original function to
1941    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1942    is used for passing in "extra" data from pcre_study().
1944    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1945    contains the following fields:
1947      flags         a bitmap indicating which of the following fields are set
1948      study_data    opaque data from pcre_study()
1949      match_limit   a way of specifying a limit on match() calls for a specific
1950                      call to pcre_exec()
1951      callout_data  data for callouts (see 49 below)
1953    The flag bits are also defined in pcre.h, and are
1959    The pcre_study() function now returns one of these new pcre_extra blocks, with
1960    the actual study data pointed to by the study_data field, and the
1961    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1962    before. That is, this change is entirely upwards-compatible and requires no
1963    change to existing code.
1965    If you want to pass in additional data to pcre_exec(), you can either place it
1966    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1967    block.
1969    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1970    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1971    times with different match limits, until it finds the minimum value needed for
1972    pcre_exec() to complete. The value is then output. This can be instructive; for
1973    most simple matches the number is quite small, but for pathological cases it
1974    gets very large very quickly.
1976    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1977    returns the size of the data block pointed to by the study_data field in a
1978    pcre_extra block, that is, the value that was passed as the argument to
1979    pcre_malloc() when PCRE was getting memory in which to place the information
1980    created by pcre_study(). The fourth argument should point to a size_t variable.
1981    pcretest has been extended so that this information is shown after a successful
1982    pcre_study() call when information about the compiled regex is being displayed.
1984    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1985    because what follows is always an absolute path. (Later: it turns out that this
1986    is more than cosmetic for MinGW, because it doesn't like empty path
1987    components.)
1989    49. Some changes have been made to the callout feature (see 28 above):
1991    (i)  A callout function now has three choices for what it returns:
1993           0  =>  success, carry on matching
1994         > 0  =>  failure at this point, but backtrack if possible
1995         < 0  =>  serious error, return this value from pcre_exec()
1997         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1998         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1999         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2000         use by callout functions. It will never be used by PCRE itself.
2002    (ii) The pcre_extra structure (see 45 above) has a void * field called
2003         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2004         pcre_callout_block structure has a field of the same name. The contents of
2005         the field passed in the pcre_extra structure are passed to the callout
2006         function in the corresponding field in the callout block. This makes it
2007         easier to use the same callout-containing regex from multiple threads. For
2008         testing, the pcretest program has a new data escape
2010           \C*n        pass the number n (may be negative) as callout_data
2012         If the callout function in pcretest receives a non-zero value as
2013         callout_data, it returns that value.
2015    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2016    there were some redundant $(CFLAGS) in commands that are now specified as
2017    $(LINK), which already includes $(CFLAGS).
2019    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2020    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2021    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2022    one-byte characters throughout. Note that case-insensitive matching applies
2023    only to characters whose values are less than 256. PCRE doesn't support the
2024    notion of cases for higher-valued characters.
2026    (i)   A character class whose characters are all within 0-255 is handled as
2027          a bit map, and the map is inverted for negative classes. Previously, a
2028          character > 255 always failed to match such a class; however it should
2029          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2031    (ii)  A negated character class with a single character < 255 is coded as
2032          "not this character" (OP_NOT). This wasn't working properly when the test
2033          character was multibyte, either singly or repeated.
2035    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2036          mode, for example: \x{100}{2,3}.
2038    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2039          singly or repeated) now correctly test multibyte characters. However,
2040          PCRE doesn't recognize any characters with values greater than 255 as
2041          digits, spaces, or word characters. Such characters always match \D, \S,
2042          and \W, and never match \d, \s, or \w.
2044    (v)   Classes may now contain characters and character ranges with values
2045          greater than 255. For example: [ab\x{100}-\x{400}].
2047    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2048          PCRE in UTF-8 mode.
2050    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2051    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2052    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2053    value.)
2055    53. The single man page has become too large. I have therefore split it up into
2056    a number of separate man pages. These also give rise to individual HTML pages;
2057    these are now put in a separate directory, and there is an index.html page that
2058    lists them all. Some hyperlinking between the pages has been installed.
2060    54. Added convenience functions for handling named capturing parentheses.
2062    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2063    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2064    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2065    are faulted.
2067    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2068    calling configure. These values are used when compiling the dftables.c program
2069    which is run to generate the source of the default character tables. They
2070    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2071    you will need to set these values.
2073    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2076    Version 3.9 02-Jan-02
2077    ---------------------
2079    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2081    2. If --disable-static was given, the building process failed when trying to
2082    build pcretest and pcregrep. (For some reason it was using libtool to compile
2083    them, which is not right, as they aren't part of the library.)
2086    Version 3.8 18-Dec-01
2087    ---------------------
2089    1. The experimental UTF-8 code was completely screwed up. It was packing the
2090    bytes in the wrong order. How dumb can you get?
2093    Version 3.7 29-Oct-01
2094    ---------------------
2096    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2097    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2098    this didn't happen under Solaris 8, where I normally test things.
2100    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2101    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2102    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2103    this fix an hour or so after the initial 3.7 release.)
2106    Version 3.6 23-Oct-01
2107    ---------------------
2109    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2110    offsets passed as NULL with zero offset count.
2112    2. The config.guess and config.sub files had not been updated when I moved to
2113    the latest autoconf.
2116    Version 3.5 15-Aug-01
2117    ---------------------
2119    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2120    had been forgotten.
2122    2. By using declared but undefined structures, we can avoid using "void"
2123    definitions in pcre.h while keeping the internal definitions of the structures
2124    private.
2126    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2127    user point of view, this means that both static and shared libraries are built
2128    by default, but this can be individually controlled. More of the work of
2129    handling this static/shared cases is now inside libtool instead of PCRE's make
2130    file.
2132    4. The pcretest utility is now installed along with pcregrep because it is
2133    useful for users (to test regexs) and by doing this, it automatically gets
2134    relinked by libtool. The documentation has been turned into a man page, so
2135    there are now .1, .txt, and .html versions in /doc.
2137    5. Upgrades to pcregrep:
2138       (i)   Added long-form option names like gnu grep.
2139       (ii)  Added --help to list all options with an explanatory phrase.
2140       (iii) Added -r, --recursive to recurse into sub-directories.
2141       (iv)  Added -f, --file to read patterns from a file.
2143    6. pcre_exec() was referring to its "code" argument before testing that
2144    argument for NULL (and giving an error if it was NULL).
2146    7. Upgraded Makefile.in to allow for compiling in a different directory from
2147    the source directory.
2149    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2150    options bits, the pointer it was passed was to an int instead of to an unsigned
2151    long int. This mattered only on 64-bit systems.
2153    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2154    generated) instead of pcre.in, which it its source. Also made the same change
2155    in several of the .c files.
2157    10. A new release of gcc defines printf() as a macro, which broke pcretest
2158    because it had an ifdef in the middle of a string argument for printf(). Fixed
2159    by using separate calls to printf().
2161    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2162    script, to force use of CR or LF instead of \n in the source. On non-Unix
2163    systems, the value can be set in config.h.
2165    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2166    absolute limit. Changed the text of the error message to make this clear, and
2167    likewise updated the man page.
2169    13. The limit of 99 on the number of capturing subpatterns has been removed.
2170    The new limit is 65535, which I hope will not be a "real" limit.
2173    Version 3.4 22-Aug-00
2174    ---------------------
2176    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2178    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2181    Version 3.3 01-Aug-00
2182    ---------------------
2184    1. If an octal character was given, but the value was greater than \377, it
2185    was not getting masked to the least significant bits, as documented. This could
2186    lead to crashes in some systems.
2188    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2189    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2191    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2192    These just pass their arguments on to (pcre_free)(), but they are provided
2193    because some uses of PCRE bind it to non-C systems that can call its functions,
2194    but cannot call free() or pcre_free() directly.
2196    4. Add "make test" as a synonym for "make check". Corrected some comments in
2197    the Makefile.
2199    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2200    Makefile.
2202    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2203    command called pgrep for grepping around the active processes.
2205    7. Added the beginnings of support for UTF-8 character strings.
2207    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2208    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2209    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2210    out for the ar command.)
2213    Version 3.2 12-May-00
2214    ---------------------
2216    This is purely a bug fixing release.
2218    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2219    of ZA. This was just one example of several cases that could provoke this bug,
2220    which was introduced by change 9 of version 2.00. The code for breaking
2221    infinite loops after an iteration that matches an empty string was't working
2222    correctly.
2224    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2225    when matched against abbab (for example). After matching an empty string, it
2226    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2227    caused it to match further down the string than it should.
2229    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2230    was there because it doesn't seem to be needed, and it causes trouble on some
2231    systems, as it is not a Standard C header. It has been removed.
2233    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2234    were reported on the Macintosh. The changes were from
2236      while ((c = *(++ptr)) != 0 && c != '\n');
2237    to
2238      while ((c = *(++ptr)) != 0 && c != '\n') ;
2240    Totally extraordinary, but if that's what it takes...
2242    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2243    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2244    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2245    assumes the way PCRE uses memmove() (always moving upwards).
2247    6. PCRE is being used in one environment where strchr() is not available. There
2248    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2249    faster code anyway.
2252    Version 3.1 09-Feb-00
2253    ---------------------
2255    The only change in this release is the fixing of some bugs in Makefile.in for
2256    the "install" target:
2258    (1) It was failing to install pcreposix.h.
2260    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2263    Version 3.0 01-Feb-00
2264    ---------------------
2266    1. Add support for the /+ modifier to perltest (to output $` like it does in
2267    pcretest).
2269    2. Add support for the /g modifier to perltest.
2271    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2272    matches null strings.
2274    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2275    pattern. Perl treats empty patterns specially - it reuses the most recent
2276    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2277    effect.
2279    5. The POSIX interface was broken in that it was just handing over the POSIX
2280    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2281    required a bigger vector, with some working space on the end. This means that
2282    the POSIX wrapper now has to get and free some memory, and copy the results.
2284    6. Added some simple autoconf support, placing the test data and the
2285    documentation in separate directories, re-organizing some of the
2286    information files, and making it build pcre-config (a GNU standard). Also added
2287    libtool support for building PCRE as a shared library, which is now the
2288    default.
2290    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2291    09 are not valid octal constants. Single digits will be used for minor values
2292    less than 10.
2294    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2295    existing programs that set these in the POSIX interface can use PCRE without
2296    modification.
2298    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2299    return all that pcre_info() returns, plus additional data. The pcre_info()
2300    function is retained for compatibility, but is considered to be obsolete.
2302    10. Added experimental recursion feature (?R) to handle one common case that
2303    Perl 5.6 will be able to do with (?p{...}).
2305    11. Added support for POSIX character classes like [:alpha:], which Perl is
2306    adopting.
2309    Version 2.08 31-Aug-99
2310    ----------------------
2312    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2313    trying to match at the startoffset position, but instead was moving forward to
2314    the next newline as if a previous match had failed.
2316    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2317    and could get into a loop if a null string was matched other than at the start
2318    of the subject.
2320    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2321    be distinguished at compile time, and for completeness also added PCRE_DATE.
2323    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2324    in GnuWin32 environments.
2327    Version 2.07 29-Jul-99
2328    ----------------------
2330    1. The documentation is now supplied in plain text form and HTML as well as in
2331    the form of man page sources.
2333    2. C++ compilers don't like assigning (void *) values to other pointer types.
2334    In particular this affects malloc(). Although there is no problem in Standard
2335    C, I've put in casts to keep C++ compilers happy.
2337    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2338    should be (const char *).
2340    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2341    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2342    However, I haven't made this a standard facility. The documentation doesn't
2343    mention it, and the Makefile doesn't support it.
2345    5. The Makefile now contains an "install" target, with editable destinations at
2346    the top of the file. The pcretest program is not installed.
2348    6. pgrep -V now gives the PCRE version number and date.
2350    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2351    causing the entire string to be ignored, instead of just the last character.
2353    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2354    non-matching string, it can take a very, very long time, even for strings of
2355    quite modest length, because of the nested recursion. PCRE now does better in
2356    some of these cases. It does this by remembering the last required literal
2357    character in the pattern, and pre-searching the subject to ensure it is present
2358    before running the real match. In other words, it applies a heuristic to detect
2359    some types of certain failure quickly, and in the above example, if presented
2360    with a string that has no trailing " it gives "no match" very quickly.
2362    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2363    other alternatives are tried instead.
2366    Version 2.06 09-Jun-99
2367    ----------------------
2369    1. Change pcretest's output for amount of store used to show just the code
2370    space, because the remainder (the data block) varies in size between 32-bit and
2371    64-bit systems.
2373    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2374    start matching at. This allows lookbehinds to work when searching for multiple
2375    occurrences in a string.
2377    3. Added additional options to pcretest for testing multiple occurrences:
2379       /+   outputs the rest of the string that follows a match
2380       /g   loops for multiple occurrences, using the new startoffset argument
2381       /G   loops for multiple occurrences by passing an incremented pointer
2383    4. PCRE wasn't doing the "first character" optimization for patterns starting
2384    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2385    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2386    the letter 'x'. On long subject strings, this gives a significant speed-up.
2389  Version 2.05 21-Apr-99  Version 2.05 21-Apr-99
2390  ----------------------  ----------------------

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