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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.
34    Version 7.2 19-Jun-07
35    ---------------------
37     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
38        which is apparently normally available under Windows.
40     2. Re-jig the pcregrep tests with different newline settings in an attempt
41        to make them independent of the local environment's newline setting.
43     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
45     4. Some of the "internals" tests were previously cut out when the link size
46        was not 2, because the output contained actual offsets. The recent new
47        "Z" feature of pcretest means that these can be cut out, making the tests
48        usable with all link sizes.
50     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
51        stack recursion. This gives a massive performance boost under BSD, but just
52        a small improvement under Linux. However, it saves one field in the frame
53        in all cases.
55     6. Added more features from the forthcoming Perl 5.10:
57        (a) (?-n) (where n is a string of digits) is a relative subroutine or
58            recursion call. It refers to the nth most recently opened parentheses.
60        (b) (?+n) is also a relative subroutine call; it refers to the nth next
61            to be opened parentheses.
63        (c) Conditions that refer to capturing parentheses can be specified
64            relatively, for example, (?(-2)... or (?(+3)...
66        (d) \K resets the start of the current match so that everything before
67            is not part of it.
69        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
71        (f) \g{name} is another synonym - part of Perl 5.10's unification of
72            reference syntax.
74        (g) (?| introduces a group in which the numbering of parentheses in each
75            alternative starts with the same number.
77        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
79     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
82     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
83        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
84        for detecting groups that can match an empty string.
86     9. A pattern with a very large number of alternatives (more than several
87        hundred) was running out of internal workspace during the pre-compile
88        phase, where pcre_compile() figures out how much memory will be needed. A
89        bit of new cunning has reduced the workspace needed for groups with
90        alternatives. The 1000-alternative test pattern now uses 12 bytes of
91        workspace instead of running out of the 4096 that are available.
93    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
95    11. Applied patch from Google to remove an optimization that didn't quite work.
96        The report of the bug said:
98          pcrecpp::RE("a*").FullMatch("aaa") matches, while
99          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
100          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
102    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
103        it matched the wrong number of bytes.
106    Version 7.1 24-Apr-07
107    ---------------------
109     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
110        that is more "standard", making use of automake and other Autotools. There
111        is some re-arrangement of the files and adjustment of comments consequent
112        on this.
114     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
115        for recursive directory scanning broke on some systems because the files
116        are not scanned in any specific order and on different systems the order
117        was different. A call to "sort" has been inserted into RunGrepTest for the
118        approprate test as a short-term fix. In the longer term there may be an
119        alternative.
121     3. I had an email from Eric Raymond about problems translating some of PCRE's
122        man pages to HTML (despite the fact that I distribute HTML pages, some
123        people do their own conversions for various reasons). The problems
124        concerned the use of low-level troff macros .br and .in. I have therefore
125        removed all such uses from the man pages (some were redundant, some could
126        be replaced by .nf/.fi pairs). The 132html script that I use to generate
127        HTML has been updated to handle .nf/.fi and to complain if it encounters
128        .br or .in.
130     4. Updated comments in configure.ac that get placed in config.h.in and also
131        arranged for config.h to be included in the distribution, with the name
132        config.h.generic, for the benefit of those who have to compile without
133        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
135     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
136        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
137        makevp.bat for the current PCRE, using the additional files
138        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
140     6. A Windows user reported a minor discrepancy with test 2, which turned out
141        to be caused by a trailing space on an input line that had got lost in his
142        copy. The trailing space was an accident, so I've just removed it.
144     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
145        that is needed.
147     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
148        as "const" (a) because they are and (b) because it helps the PHP
149        maintainers who have recently made a script to detect big data structures
150        in the php code that should be moved to the .rodata section. I remembered
151        to update Builducptable as well, so it won't revert if ucptable.h is ever
152        re-created.
154     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
155        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
156        order to be able to cut out the UTF-8 tables in the latter when UTF-8
157        support is not required. This saves 1.5-2K of code, which is important in
158        some applications.
160        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
161        so as not to refer to the tables, even though these functions will never be
162        called when UTF-8 support is disabled. Otherwise there are problems with a
163        shared library.
165    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
167        (a) It was defining its arguments as char * instead of void *.
169        (b) It was assuming that all moves were upwards in memory; this was true
170            a long time ago when I wrote it, but is no longer the case.
172        The emulated memove() is provided for those environments that have neither
173        memmove() nor bcopy(). I didn't think anyone used it these days, but that
174        is clearly not the case, as these two bugs were recently reported.
176    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
177        and Detrail to create the HTML documentation, the .txt form of the man
178        pages, and it removes trailing spaces from listed files. It also creates
179        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
180        case, it wraps all the #defines with #ifndefs. This script should be run
181        before "make dist".
183    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
184        with Unicode property support.
186        (a) For a maximizing quantifier, if the two different cases of the
187            character were of different lengths in their UTF-8 codings (there are
188            some cases like this - I found 11), and the matching function had to
189            back up over a mixture of the two cases, it incorrectly assumed they
190            were both the same length.
192        (b) When PCRE was configured to use the heap rather than the stack for
193            recursion during matching, it was not correctly preserving the data for
194            the other case of a UTF-8 character when checking ahead for a match
195            while processing a minimizing repeat. If the check also involved
196            matching a wide character, but failed, corruption could cause an
197            erroneous result when trying to check for a repeat of the original
198            character.
200    13. Some tidying changes to the testing mechanism:
202        (a) The RunTest script now detects the internal link size and whether there
203            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
204            values substituted by "configure". (The RunGrepTest script already did
205            this for UTF-8.) The configure.ac script no longer substitutes the
206            relevant variables.
208        (b) The debugging options /B and /D in pcretest show the compiled bytecode
209            with length and offset values. This means that the output is different
210            for different internal link sizes. Test 2 is skipped for link sizes
211            other than 2 because of this, bypassing the problem. Unfortunately,
212            there was also a test in test 3 (the locale tests) that used /B and
213            failed for link sizes other than 2. Rather than cut the whole test out,
214            I have added a new /Z option to pcretest that replaces the length and
215            offset values with spaces. This is now used to make test 3 independent
216            of link size. (Test 2 will be tidied up later.)
218    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
219        segmentation fault instead of returning the appropriate error message.
221    15. In multiline mode when the newline sequence was set to "any", the pattern
222        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
223        This doesn't seem right; it now treats the CRLF combination as the line
224        ending, and so does not match in that case. It's only a pattern such as ^$
225        that would hit this one: something like ^ABC$ would have failed after \r
226        and then tried again after \r\n.
228    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
229        in an attempt to make files that differ only in their line terminators
230        compare equal. This works on Linux.
232    17. Under certain error circumstances pcregrep might try to free random memory
233        as it exited. This is now fixed, thanks to valgrind.
235    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
236        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
237        was because its rules for how to advance for /g after matching an empty
238        string at the end of a line did not allow for this case. They now check for
239        it specially.
241    20. pcretest is supposed to handle patterns and data of any length, by
242        extending its buffers when necessary. It was getting this wrong when the
243        buffer for a data line had to be extended.
245    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
246        CRLF as a newline sequence.
248    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
249        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
250        I have nevertheless tidied it up.
252    23. Added some casts to kill warnings from HP-UX ia64 compiler.
254    24. Added a man page for pcre-config.
257    Version 7.0 19-Dec-06
258    ---------------------
260     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
261        moving to gcc 4.1.1.
263     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
264        sys/time.h, which is documented as needed for this function. It doesn't
265        seem to matter on Linux, but it showed up on some releases of OS X.
267     3. It seems that there are systems where bytes whose values are greater than
268        127 match isprint() in the "C" locale. The "C" locale should be the
269        default when a C program starts up. In most systems, only ASCII printing
270        characters match isprint(). This difference caused the output from pcretest
271        to vary, making some of the tests fail. I have changed pcretest so that:
273        (a) When it is outputting text in the compiled version of a pattern, bytes
274            other than 32-126 are always shown as hex escapes.
276        (b) When it is outputting text that is a matched part of a subject string,
277            it does the same, unless a different locale has been set for the match
278            (using the /L modifier). In this case, it uses isprint() to decide.
280     4. Fixed a major bug that caused incorrect computation of the amount of memory
281        required for a compiled pattern when options that changed within the
282        pattern affected the logic of the preliminary scan that determines the
283        length. The relevant options are -x, and -i in UTF-8 mode. The result was
284        that the computed length was too small. The symptoms of this bug were
285        either the PCRE error "internal error: code overflow" from pcre_compile(),
286        or a glibc crash with a message such as "pcretest: free(): invalid next
287        size (fast)". Examples of patterns that provoked this bug (shown in
288        pcretest format) are:
290          /(?-x: )/x
291          /(?x)(?-x: \s*#\s*)/
292          /((?i)[\x{c0}])/8
293          /(?i:[\x{c0}])/8
295        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
296        is now done differently.
298     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
299        wrapper classes; (b) implement a new function in the C++ scanner that is
300        more efficient than the old way of doing things because it avoids levels of
301        recursion in the regex matching; (c) add a paragraph to the documentation
302        for the FullMatch() function.
304     6. The escape sequence \n was being treated as whatever was defined as
305        "newline". Not only was this contrary to the documentation, which states
306        that \n is character 10 (hex 0A), but it also went horribly wrong when
307        "newline" was defined as CRLF. This has been fixed.
309     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
310        was being set to -1 for the "end of line" case (supposedly a value that no
311        character can have). Though this value is never used (the check for end of
312        line is "zero bytes in current character"), it caused compiler complaints.
313        I've changed it to 0xffffffff.
315     8. In pcre_version.c, the version string was being built by a sequence of
316        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
317        string (as it is for production releases) called a macro with an empty
318        argument. The C standard says the result of this is undefined. The gcc
319        compiler treats it as an empty string (which was what was wanted) but it is
320        reported that Visual C gives an error. The source has been hacked around to
321        avoid this problem.
323     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
324        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
325        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
326        of them did).
328    10. Originally, pcretest opened its input and output without "b"; then I was
329        told that "b" was needed in some environments, so it was added for release
330        5.0 to both the input and output. (It makes no difference on Unix-like
331        systems.) Later I was told that it is wrong for the input on Windows. I've
332        now abstracted the modes into two macros, to make it easier to fiddle with
333        them, and removed "b" from the input mode under Windows.
335    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
337    12. Added -help and --help to pcretest as an official way of being reminded
338        of the options.
340    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
341        and pcrecpp.cc because they annoy compilers at high warning levels.
343    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
345    15. Fixed an occurrence of == in configure.ac that should have been = (shell
346        scripts are not C programs :-) and which was not noticed because it works
347        on Linux.
349    16. pcretest is supposed to handle any length of pattern and data line (as one
350        line or as a continued sequence of lines) by extending its input buffer if
351        necessary. This feature was broken for very long pattern lines, leading to
352        a string of junk being passed to pcre_compile() if the pattern was longer
353        than about 50K.
355    17. I have done a major re-factoring of the way pcre_compile() computes the
356        amount of memory needed for a compiled pattern. Previously, there was code
357        that made a preliminary scan of the pattern in order to do this. That was
358        OK when PCRE was new, but as the facilities have expanded, it has become
359        harder and harder to keep it in step with the real compile phase, and there
360        have been a number of bugs (see for example, 4 above). I have now found a
361        cunning way of running the real compile function in a "fake" mode that
362        enables it to compute how much memory it would need, while actually only
363        ever using a few hundred bytes of working memory and without too many
364        tests of the mode. This should make future maintenance and development
365        easier. A side effect of this work is that the limit of 200 on the nesting
366        depth of parentheses has been removed (though this was never a serious
367        limitation, I suspect). However, there is a downside: pcre_compile() now
368        runs more slowly than before (30% or more, depending on the pattern). I
369        hope this isn't a big issue. There is no effect on runtime performance.
371    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
372        newline (only possible for the last line of a file) and it was a
373        pattern that set a locale (followed by /Lsomething), pcretest crashed.
375    19. Added additional timing features to pcretest. (1) The -tm option now times
376        matching only, not compiling. (2) Both -t and -tm can be followed, as a
377        separate command line item, by a number that specifies the number of
378        repeats to use when timing. The default is 50000; this gives better
379        precision, but takes uncomfortably long for very large patterns.
381    20. Extended pcre_study() to be more clever in cases where a branch of a
382        subpattern has no definite first character. For example, (a*|b*)[cd] would
383        previously give no result from pcre_study(). Now it recognizes that the
384        first character must be a, b, c, or d.
386    21. There was an incorrect error "recursive call could loop indefinitely" if
387        a subpattern (or the entire pattern) that was being tested for matching an
388        empty string contained only one non-empty item after a nested subpattern.
389        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
390        incorrectly, because the \d was being skipped in the check.
392    22. The pcretest program now has a new pattern option /B and a command line
393        option -b, which is equivalent to adding /B to every pattern. This causes
394        it to show the compiled bytecode, without the additional information that
395        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
396        is the same as /B/I).
398    23. A new optimization is now able automatically to treat some sequences such
399        as a*b as a*+b. More specifically, if something simple (such as a character
400        or a simple class like \d) has an unlimited quantifier, and is followed by
401        something that cannot possibly match the quantified thing, the quantifier
402        is automatically "possessified".
404    24. A recursive reference to a subpattern whose number was greater than 39
405        went wrong under certain circumstances in UTF-8 mode. This bug could also
406        have affected the operation of pcre_study().
408    25. Realized that a little bit of performance could be had by replacing
409        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
411    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
413    27. Possessive quantifiers such as a++ were previously implemented by turning
414        them into atomic groups such as ($>a+). Now they have their own opcodes,
415        which improves performance. This includes the automatically created ones
416        from 23 above.
418    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
419        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
420        the first matched character to be a colon. This applied both to named and
421        numbered groups.
423    29. The ucpinternal.h header file was missing its idempotency #ifdef.
425    30. I was sent a "project" file called libpcre.a.dev which I understand makes
426        building PCRE on Windows easier, so I have included it in the distribution.
428    31. There is now a check in pcretest against a ridiculously large number being
429        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
430        loop, the loop is abandoned.
432    32. Forward references to subpatterns in conditions such as (?(2)...) where
433        subpattern 2 is defined later cause pcre_compile() to search forwards in
434        the pattern for the relevant set of parentheses. This search went wrong
435        when there were unescaped parentheses in a character class, parentheses
436        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
438    33. "Subroutine" calls and backreferences were previously restricted to
439        referencing subpatterns earlier in the regex. This restriction has now
440        been removed.
442    34. Added a number of extra features that are going to be in Perl 5.10. On the
443        whole, these are just syntactic alternatives for features that PCRE had
444        previously implemented using the Python syntax or my own invention. The
445        other formats are all retained for compatibility.
447        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
448            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
449            also .NET compatible.
451        (b) A recursion or subroutine call to a named group can now be defined as
452            (?&name) as well as (?P>name).
454        (c) A backreference to a named group can now be defined as \k<name> or
455            \k'name' as well as (?P=name). The new forms, as well as being in Perl
456            5.10, are also .NET compatible.
458        (d) A conditional reference to a named group can now use the syntax
459            (?(<name>) or (?('name') as well as (?(name).
461        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
462            groups (named and numbered) that are never evaluated inline, but can be
463            called as "subroutines" from elsewhere. In effect, the DEFINE condition
464            is always false. There may be only one alternative in such a group.
466        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
467            as the simple (?(R). The condition is true only if the most recent
468            recursion is that of the given number or name. It does not search out
469            through the entire recursion stack.
471        (g) The escape \gN or \g{N} has been added, where N is a positive or
472            negative number, specifying an absolute or relative reference.
474    35. Tidied to get rid of some further signed/unsigned compiler warnings and
475        some "unreachable code" warnings.
477    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
478        things, this adds five new scripts.
480    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
481        There were also incompatibilities regarding the handling of \Q..\E inside
482        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
483        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
485    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
486        matches an empty string, and forcibly breaks the loop. There were bugs in
487        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
488        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
489        separate and independent bugs (that affected different cases) have been
490        fixed.
492    39. Refactored the code to abolish the use of different opcodes for small
493        capturing bracket numbers. This is a tidy that I avoided doing when I
494        removed the limit on the number of capturing brackets for 3.5 back in 2001.
495        The new approach is not only tidier, it makes it possible to reduce the
496        memory needed to fix the previous bug (38).
498    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
499        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
500        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
501        mode.
503    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
504        report.
506    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
507        copy construction and assignment in the C++ wrapper.
509    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
510        couple of bugs that could have given wrong results in the "--newline=crlf"
511        case.
513    44. Added a number of casts and did some reorganization of signed/unsigned int
514        variables following suggestions from Dair Grant. Also renamed the variable
515        "this" as "item" because it is a C++ keyword.
517    45. Arranged for dftables to add
519          #include "pcre_internal.h"
521        to pcre_chartables.c because without it, gcc 4.x may remove the array
522        definition from the final binary if PCRE is built into a static library and
523        dead code stripping is activated.
525    46. For an unanchored pattern, if a match attempt fails at the start of a
526        newline sequence, and the newline setting is CRLF or ANY, and the next two
527        characters are CRLF, advance by two characters instead of one.
530    Version 6.7 04-Jul-06
531    ---------------------
533     1. In order to handle tests when input lines are enormously long, pcretest has
534        been re-factored so that it automatically extends its buffers when
535        necessary. The code is crude, but this _is_ just a test program. The
536        default size has been increased from 32K to 50K.
538     2. The code in pcre_study() was using the value of the re argument before
539        testing it for NULL. (Of course, in any sensible call of the function, it
540        won't be NULL.)
542     3. The memmove() emulation function in pcre_internal.h, which is used on
543        systems that lack both memmove() and bcopy() - that is, hardly ever -
544        was missing a "static" storage class specifier.
546     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
547        containing an extended class (one that cannot be represented by a bitmap
548        because it contains high-valued characters or Unicode property items, e.g.
549        [\pZ]). Almost always one would set UTF-8 mode when processing such a
550        pattern, but PCRE should not loop if you do not (it no longer does).
551        [Detail: two cases were found: (a) a repeated subpattern containing an
552        extended class; (b) a recursive reference to a subpattern that followed a
553        previous extended class. It wasn't skipping over the extended class
554        correctly when UTF-8 mode was not set.]
556     5. A negated single-character class was not being recognized as fixed-length
557        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
558        compile error "lookbehind assertion is not fixed length".
560     6. The RunPerlTest auxiliary script was showing an unexpected difference
561        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
562        write a Perl script that can interpret lines of an input file either as
563        byte characters or as UTF-8, which is what "perltest" was being required to
564        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
565        can't do is switch easily at run time between having the "use utf8;" pragma
566        or not. In the end, I fudged it by using the RunPerlTest script to insert
567        "use utf8;" explicitly for the UTF-8 tests.
569     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
570        the end of the subject string, contrary to the documentation and to what
571        Perl does. This was true of both matching functions. Now it matches only at
572        the start of the subject and immediately after *internal* newlines.
574     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
575        a pointer to an int instead of a pointer to an unsigned long int. This
576        caused problems on 64-bit systems.
578     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
579        instance of the 'standard' template library not being so standard".
581    10. There was no check on the number of named subpatterns nor the maximum
582        length of a subpattern name. The product of these values is used to compute
583        the size of the memory block for a compiled pattern. By supplying a very
584        long subpattern name and a large number of named subpatterns, the size
585        computation could be caused to overflow. This is now prevented by limiting
586        the length of names to 32 characters, and the number of named subpatterns
587        to 10,000.
589    11. Subpatterns that are repeated with specific counts have to be replicated in
590        the compiled pattern. The size of memory for this was computed from the
591        length of the subpattern and the repeat count. The latter is limited to
592        65535, but there was no limit on the former, meaning that integer overflow
593        could in principle occur. The compiled length of a repeated subpattern is
594        now limited to 30,000 bytes in order to prevent this.
596    12. Added the optional facility to have named substrings with the same name.
598    13. Added the ability to use a named substring as a condition, using the
599        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
600        are numbers (not recommended). Forward references are permitted.
602    14. Added forward references in named backreferences (if you see what I mean).
604    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
605        pattern could run off the end of the subject. For example, the pattern
606        "(?s)(.{1,5})"8 did this with the subject "ab".
608    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
609        PCRE_CASELESS was set when matching characters that were quantified with ?
610        or *.
612    17. A character class other than a single negated character that had a minimum
613        but no maximum quantifier - for example [ab]{6,} - was not handled
614        correctly by pce_dfa_exec(). It would match only one character.
616    18. A valid (though odd) pattern that looked like a POSIX character
617        class but used an invalid character after [ (for example [[,abc,]]) caused
618        pcre_compile() to give the error "Failed: internal error: code overflow" or
619        in some cases to crash with a glibc free() error. This could even happen if
620        the pattern terminated after [[ but there just happened to be a sequence of
621        letters, a binary zero, and a closing ] in the memory that followed.
623    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
624        over the years. Originally (before any Unicode support), just the bottom 8
625        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
626        output from "man perlunicode" includes this:
628          The regular expression compiler produces polymorphic opcodes.  That
629          is, the pattern adapts to the data and automatically switches to
630          the Unicode character scheme when presented with Unicode data--or
631          instead uses a traditional byte scheme when presented with byte
632          data.
634        Sadly, a wide octal escape does not cause a switch, and in a string with
635        no other multibyte characters, these octal escapes are treated as before.
636        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
637        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
638        Unicode string.
640        I have not perpetrated such confusion in PCRE. Up till now, it took just
641        the bottom 8 bits, as in old Perl. I have now made octal escapes with
642        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
643        translate to the appropriate multibyte character.
645    29. Applied some refactoring to reduce the number of warnings from Microsoft
646        and Borland compilers. This has included removing the fudge introduced
647        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
648        a warning about an unused variable.
650    21. PCRE has not included VT (character 0x0b) in the set of whitespace
651        characters since release 4.0, because Perl (from release 5.004) does not.
652        [Or at least, is documented not to: some releases seem to be in conflict
653        with the documentation.] However, when a pattern was studied with
654        pcre_study() and all its branches started with \s, PCRE still included VT
655        as a possible starting character. Of course, this did no harm; it just
656        caused an unnecessary match attempt.
658    22. Removed a now-redundant internal flag bit that recorded the fact that case
659        dependency changed within the pattern. This was once needed for "required
660        byte" processing, but is no longer used. This recovers a now-scarce options
661        bit. Also moved the least significant internal flag bit to the most-
662        significant bit of the word, which was not previously used (hangover from
663        the days when it was an int rather than a uint) to free up another bit for
664        the future.
666    23. Added support for CRLF line endings as well as CR and LF. As well as the
667        default being selectable at build time, it can now be changed at runtime
668        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
669        specify that it is scanning data with non-default line endings.
671    24. Changed the definition of CXXLINK to make it agree with the definition of
672        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
674    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
675        recursions. This makes a big different to stack usage for some patterns.
677    26. If a subpattern containing a named recursion or subroutine reference such
678        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
679        the space required for the compiled pattern went wrong and gave too small a
680        value. Depending on the environment, this could lead to "Failed: internal
681        error: code overflow at offset 49" or "glibc detected double free or
682        corruption" errors.
684    27. Applied patches from Google (a) to support the new newline modes and (b) to
685        advance over multibyte UTF-8 characters in GlobalReplace.
687    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
688        difference for some implementation of PCRE in some Windows version.
690    29. Added some extra testing facilities to pcretest:
692        \q<number>   in a data line sets the "match limit" value
693        \Q<number>   in a data line sets the "match recursion limt" value
694        -S <number>  sets the stack size, where <number> is in megabytes
696        The -S option isn't available for Windows.
699    Version 6.6 06-Feb-06
700    ---------------------
702     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
703        in pcreposix.h. I have copied the definition from pcre.h.
705     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
706        because pcre.h is no longer a built file.
708     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
709        not normally included in the compiled code.
712    Version 6.5 01-Feb-06
713    ---------------------
715     1. When using the partial match feature with pcre_dfa_exec(), it was not
716        anchoring the second and subsequent partial matches at the new starting
717        point. This could lead to incorrect results. For example, with the pattern
718        /1234/, partially matching against "123" and then "a4" gave a match.
720     2. Changes to pcregrep:
722        (a) All non-match returns from pcre_exec() were being treated as failures
723            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
724            error message is output. Some extra information is given for the
725            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
726            probably the only errors that are likely to be caused by users (by
727            specifying a regex that has nested indefinite repeats, for instance).
728            If there are more than 20 of these errors, pcregrep is abandoned.
730        (b) A binary zero was treated as data while matching, but terminated the
731            output line if it was written out. This has been fixed: binary zeroes
732            are now no different to any other data bytes.
734        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
735            used to set a locale for matching. The --locale=xxxx long option has
736            been added (no short equivalent) to specify a locale explicitly on the
737            pcregrep command, overriding the environment variables.
739        (d) When -B was used with -n, some line numbers in the output were one less
740            than they should have been.
742        (e) Added the -o (--only-matching) option.
744        (f) If -A or -C was used with -c (count only), some lines of context were
745            accidentally printed for the final match.
747        (g) Added the -H (--with-filename) option.
749        (h) The combination of options -rh failed to suppress file names for files
750            that were found from directory arguments.
752        (i) Added the -D (--devices) and -d (--directories) options.
754        (j) Added the -F (--fixed-strings) option.
756        (k) Allow "-" to be used as a file name for -f as well as for a data file.
758        (l) Added the --colo(u)r option.
760        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
761            is not present by default.
763     3. A nasty bug was discovered in the handling of recursive patterns, that is,
764        items such as (?R) or (?1), when the recursion could match a number of
765        alternatives. If it matched one of the alternatives, but subsequently,
766        outside the recursion, there was a failure, the code tried to back up into
767        the recursion. However, because of the way PCRE is implemented, this is not
768        possible, and the result was an incorrect result from the match.
770        In order to prevent this happening, the specification of recursion has
771        been changed so that all such subpatterns are automatically treated as
772        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
774     4. I had overlooked the fact that, in some locales, there are characters for
775        which isalpha() is true but neither isupper() nor islower() are true. In
776        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
777        and ordfeminine) are like this. This affected the treatment of \w and \W
778        when they appeared in character classes, but not when they appeared outside
779        a character class. The bit map for "word" characters is now created
780        separately from the results of isalnum() instead of just taking it from the
781        upper, lower, and digit maps. (Plus the underscore character, of course.)
783     5. The above bug also affected the handling of POSIX character classes such as
784        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
785        permanent tables. Instead, the bit maps for such a class were previously
786        created as the appropriate unions of the upper, lower, and digit bitmaps.
787        Now they are created by subtraction from the [[:word:]] class, which has
788        its own bitmap.
790     6. The [[:blank:]] character class matches horizontal, but not vertical space.
791        It is created by subtracting the vertical space characters (\x09, \x0a,
792        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
793        subtraction was done in the overall bitmap for a character class, meaning
794        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
795        be recognized. This bug has been fixed.
797     7. Patches from the folks at Google:
799          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
800          real life, but is still worth protecting against".
802          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
803          regular expressions".
805          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
806          have it.
808          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
809          "configure" and the latter not, in order to fix a problem somebody had
810          with compiling the Arg class on HP-UX.
812          (e) Improve the error-handling of the C++ wrapper a little bit.
814          (f) New tests for checking recursion limiting.
816     8. The pcre_memmove() function, which is used only if the environment does not
817        have a standard memmove() function (and is therefore rarely compiled),
818        contained two bugs: (a) use of int instead of size_t, and (b) it was not
819        returning a result (though PCRE never actually uses the result).
821     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
822        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
823        returned instead of calling malloc() with an overflowing number that would
824        most likely cause subsequent chaos.
826    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
828    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
829        with this option is matched, the nmatch and pmatch options of regexec() are
830        ignored.
832    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
833        provided in case anyone wants to the the POSIX interface with UTF-8
834        strings.
836    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
837        C++ linking (needed for some HP-UX environments).
839    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
840        (unused parameter) and in the pcre_printint() function (omitted "default"
841        switch label when the default is to do nothing).
843    15. Added some code to make it possible, when PCRE is compiled as a C++
844        library, to replace subject pointers for pcre_exec() with a smart pointer
845        class, thus making it possible to process discontinuous strings.
847    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
848        much the same function. They were added by different people who were trying
849        to make PCRE easy to compile on non-Unix systems. It has been suggested
850        that PCRE_EXPORT be abolished now that there is more automatic apparatus
851        for compiling on Windows systems. I have therefore replaced it with
852        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
853        defaults to "extern" for C or "extern C" for C++, which works fine on
854        Unix-like systems. It is now possible to override the value of PCRE_DATA_
855        SCOPE with something explicit in config.h. In addition:
857        (a) pcreposix.h still had just "extern" instead of either of these macros;
858            I have replaced it with PCRE_DATA_SCOPE.
860        (b) Functions such as _pcre_xclass(), which are internal to the library,
861            but external in the C sense, all had PCRE_EXPORT in their definitions.
862            This is apparently wrong for the Windows case, so I have removed it.
863            (It makes no difference on Unix-like systems.)
865    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
866        of recursive calls to match(). This is different to MATCH_LIMIT because
867        that limits the total number of calls to match(), not all of which increase
868        the depth of recursion. Limiting the recursion depth limits the amount of
869        stack (or heap if NO_RECURSE is set) that is used. The default can be set
870        when PCRE is compiled, and changed at run time. A patch from Google adds
871        this functionality to the C++ interface.
873    18. Changes to the handling of Unicode character properties:
875        (a) Updated the table to Unicode 4.1.0.
877        (b) Recognize characters that are not in the table as "Cn" (undefined).
879        (c) I revised the way the table is implemented to a much improved format
880            which includes recognition of ranges. It now supports the ranges that
881            are defined in UnicodeData.txt, and it also amalgamates other
882            characters into ranges. This has reduced the number of entries in the
883            table from around 16,000 to around 3,000, thus reducing its size
884            considerably. I realized I did not need to use a tree structure after
885            all - a binary chop search is just as efficient. Having reduced the
886            number of entries, I extended their size from 6 bytes to 8 bytes to
887            allow for more data.
889        (d) Added support for Unicode script names via properties such as \p{Han}.
891    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
892        matching that character.
894    20. When matching a repeated Unicode property with a minimum greater than zero,
895        (for example \pL{2,}), PCRE could look past the end of the subject if it
896        reached it while seeking the minimum number of characters. This could
897        happen only if some of the characters were more than one byte long, because
898        there is a check for at least the minimum number of bytes.
900    21. Refactored the implementation of \p and \P so as to be more general, to
901        allow for more different types of property in future. This has changed the
902        compiled form incompatibly. Anybody with saved compiled patterns that use
903        \p or \P will have to recompile them.
905    22. Added "Any" and "L&" to the supported property types.
907    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
908        but give a compile time error if the value is greater than 0xff.
910    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
911        accidentally not being installed or uninstalled.
913    25. The pcre.h file was built from pcre.h.in, but the only changes that were
914        made were to insert the current release number. This seemed silly, because
915        it made things harder for people building PCRE on systems that don't run
916        "configure". I have turned pcre.h into a distributed file, no longer built
917        by "configure", with the version identification directly included. There is
918        no longer a pcre.h.in file.
920        However, this change necessitated a change to the pcre-config script as
921        well. It is built from pcre-config.in, and one of the substitutions was the
922        release number. I have updated configure.ac so that ./configure now finds
923        the release number by grepping pcre.h.
925    26. Added the ability to run the tests under valgrind.
928    Version 6.4 05-Sep-05
929    ---------------------
931     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
932        "--" to be printed when multiple files were scanned, even when none of the
933        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
934        consider it to be a bug, and have restored the previous behaviour.
936     2. A couple of code tidies to get rid of compiler warnings.
938     3. The pcretest program used to cheat by referring to symbols in the library
939        whose names begin with _pcre_. These are internal symbols that are not
940        really supposed to be visible externally, and in some environments it is
941        possible to suppress them. The cheating is now confined to including
942        certain files from the library's source, which is a bit cleaner.
944     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
945        file's purpose clearer.
947     5. Reorganized pcre_ucp_findchar().
950    Version 6.3 15-Aug-05
951    ---------------------
953     1. The file libpcre.pc.in did not have general read permission in the tarball.
955     2. There were some problems when building without C++ support:
957        (a) If C++ support was not built, "make install" and "make test" still
958            tried to test it.
960        (b) There were problems when the value of CXX was explicitly set. Some
961            changes have been made to try to fix these, and ...
963        (c) --disable-cpp can now be used to explicitly disable C++ support.
965        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
966            backslash in a target when C++ was disabled. This confuses some
967            versions of "make", apparently. Using an intermediate variable solves
968            this. (Same for CPP_LOBJ.)
970     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
971        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
972        necessary on certain architectures.
974     4. Added a setting of -export-symbols-regex to the link command to remove
975        those symbols that are exported in the C sense, but actually are local
976        within the library, and not documented. Their names all begin with
977        "_pcre_". This is not a perfect job, because (a) we have to except some
978        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
979        available (and never for static libraries). I have made a note to try to
980        find a way round (a) in the future.
983    Version 6.2 01-Aug-05
984    ---------------------
986     1. There was no test for integer overflow of quantifier values. A construction
987        such as {1111111111111111} would give undefined results. What is worse, if
988        a minimum quantifier for a parenthesized subpattern overflowed and became
989        negative, the calculation of the memory size went wrong. This could have
990        led to memory overwriting.
992     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
994     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
995        operating environments where this matters.
997     4. Applied Giuseppe Maxia's patch to add additional features for controlling
998        PCRE options from within the C++ wrapper.
1000     5. Named capturing subpatterns were not being correctly counted when a pattern
1001        was compiled. This caused two problems: (a) If there were more than 100
1002        such subpatterns, the calculation of the memory needed for the whole
1003        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1004        back references of the form \12, where the number was greater than 9, were
1005        not recognized as back references, even though there were sufficient
1006        previous subpatterns.
1008     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1009        versions of gcc, e.g. 2.95.4.
1012    Version 6.1 21-Jun-05
1013    ---------------------
1015     1. There was one reference to the variable "posix" in pcretest.c that was not
1016        surrounded by "#if !defined NOPOSIX".
1018     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1019        the cross-check on the old pcre_info() function, for the benefit of the
1020        cut-down version of PCRE that is currently imported into Exim.
1022     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1023        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1024        patterns that start (?i) but I don't think that matters. The use of (?i) is
1025        just an example; this all applies to the other options as well.
1027     4. Since libtool seems to echo the compile commands it is issuing, the output
1028        from "make" can be reduced a bit by putting "@" in front of each libtool
1029        compile command.
1031     5. Patch from the folks at Google for configure.in to be a bit more thorough
1032        in checking for a suitable C++ installation before trying to compile the
1033        C++ stuff. This should fix a reported problem when a compiler was present,
1034        but no suitable headers.
1036     6. The man pages all had just "PCRE" as their title. I have changed them to
1037        be the relevant file name. I have also arranged that these names are
1038        retained in the file doc/pcre.txt, which is a concatenation in text format
1039        of all the man pages except the little individual ones for each function.
1041     7. The NON-UNIX-USE file had not been updated for the different set of source
1042        files that come with release 6. I also added a few comments about the C++
1043        wrapper.
1046    Version 6.0 07-Jun-05
1047    ---------------------
1049     1. Some minor internal re-organization to help with my DFA experiments.
1051     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1052        didn't matter for the library itself when fully configured, but did matter
1053        when compiling without UCP support, or within Exim, where the ucp files are
1054        not imported.
1056     3. Refactoring of the library code to split up the various functions into
1057        different source modules. The addition of the new DFA matching code (see
1058        below) to a single monolithic source would have made it really too
1059        unwieldy, quite apart from causing all the code to be include in a
1060        statically linked application, when only some functions are used. This is
1061        relevant even without the DFA addition now that patterns can be compiled in
1062        one application and matched in another.
1064        The downside of splitting up is that there have to be some external
1065        functions and data tables that are used internally in different modules of
1066        the library but which are not part of the API. These have all had their
1067        names changed to start with "_pcre_" so that they are unlikely to clash
1068        with other external names.
1070     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1071        a different (DFA) algorithm. Although it is slower than the original
1072        function, it does have some advantages for certain types of matching
1073        problem.
1075     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1076        including restarting after a partial match.
1078     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1079        defined when compiling for Windows was sent to me. I have put it into the
1080        code, though I have no means of testing or verifying it.
1082     7. Added the pcre_refcount() auxiliary function.
1084     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1085        match before or at the first newline in the subject string. In pcretest,
1086        the /f option on a pattern can be used to set this.
1088     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1089        would behave wrongly. This has been present in PCRE since release 4.0.
1091    10. A number of changes to the pcregrep command:
1093        (a) Refactored how -x works; insert ^(...)$ instead of setting
1094            PCRE_ANCHORED and checking the length, in preparation for adding
1095            something similar for -w.
1097        (b) Added the -w (match as a word) option.
1099        (c) Refactored the way lines are read and buffered so as to have more
1100            than one at a time available.
1102        (d) Implemented a pcregrep test script.
1104        (e) Added the -M (multiline match) option. This allows patterns to match
1105            over several lines of the subject. The buffering ensures that at least
1106            8K, or the rest of the document (whichever is the shorter) is available
1107            for matching (and similarly the previous 8K for lookbehind assertions).
1109        (f) Changed the --help output so that it now says
1111              -w, --word-regex(p)
1113            instead of two lines, one with "regex" and the other with "regexp"
1114            because that confused at least one person since the short forms are the
1115            same. (This required a bit of code, as the output is generated
1116            automatically from a table. It wasn't just a text change.)
1118        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1119            option but starts with a hyphen. Could be a pattern or a path name
1120            starting with a hyphen, for instance.
1122        (h) "-" can be given as a file name to represent stdin.
1124        (i) When file names are being printed, "(standard input)" is used for
1125            the standard input, for compatibility with GNU grep. Previously
1126            "<stdin>" was used.
1128        (j) The option --label=xxx can be used to supply a name to be used for
1129            stdin when file names are being printed. There is no short form.
1131        (k) Re-factored the options decoding logic because we are going to add
1132            two more options that take data. Such options can now be given in four
1133            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1135        (l) Added the -A, -B, and -C options for requesting that lines of context
1136            around matches be printed.
1138        (m) Added the -L option to print the names of files that do not contain
1139            any matching lines, that is, the complement of -l.
1141        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1142            continue to scan other files.
1144        (o) The -s option was incorrectly implemented. For compatibility with other
1145            greps, it now suppresses the error message for a non-existent or non-
1146            accessible file (but not the return code). There is a new option called
1147            -q that suppresses the output of matching lines, which was what -s was
1148            previously doing.
1150        (p) Added --include and --exclude options to specify files for inclusion
1151            and exclusion when recursing.
1153    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1154        Hopefully, it now does.
1156    12. Missing cast in pcre_study().
1158    13. Added an "uninstall" target to the makefile.
1160    14. Replaced "extern" in the function prototypes in Makefile.in with
1161        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1162        world, but is set differently for Windows.
1164    15. Added a second compiling function called pcre_compile2(). The only
1165        difference is that it has an extra argument, which is a pointer to an
1166        integer error code. When there is a compile-time failure, this is set
1167        non-zero, in addition to the error test pointer being set to point to an
1168        error message. The new argument may be NULL if no error number is required
1169        (but then you may as well call pcre_compile(), which is now just a
1170        wrapper). This facility is provided because some applications need a
1171        numeric error indication, but it has also enabled me to tidy up the way
1172        compile-time errors are handled in the POSIX wrapper.
1174    16. Added VPATH=.libs to the makefile; this should help when building with one
1175        prefix path and installing with another. (Or so I'm told by someone who
1176        knows more about this stuff than I do.)
1178    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1179        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1180        match everything, including newlines. This is not POSIX-compatible, but
1181        somebody wanted the feature. From pcretest it can be activated by using
1182        both the P and the s flags.
1184    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1186    19. libpcre.pc was being incorrectly installed as executable.
1188    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1189        it now also looks for '\r' so that it will work unmodified on Windows.
1191    21. Added Google's contributed C++ wrapper to the distribution.
1193    22. Added some untidy missing memory free() calls in pcretest, to keep
1194        Electric Fence happy when testing.
1198    Version 5.0 13-Sep-04
1199    ---------------------
1201     1. Internal change: literal characters are no longer packed up into items
1202        containing multiple characters in a single byte-string. Each character
1203        is now matched using a separate opcode. However, there may be more than one
1204        byte in the character in UTF-8 mode.
1206     2. The pcre_callout_block structure has two new fields: pattern_position and
1207        next_item_length. These contain the offset in the pattern to the next match
1208        item, and its length, respectively.
1210     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1211        insertion of callouts before each pattern item. Added the /C option to
1212        pcretest to make use of this.
1214     4. On the advice of a Windows user, the lines
1216          #if defined(_WIN32) || defined(WIN32)
1217          _setmode( _fileno( stdout ), 0x8000 );
1218          #endif  /* defined(_WIN32) || defined(WIN32) */
1220        have been added to the source of pcretest. This apparently does useful
1221        magic in relation to line terminators.
1223     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1224        for the benefit of those environments where the "b" makes a difference.
1226     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1227        to know about it. I have put a hack into configure.in that adds in code
1228        to set GCC=yes if CC=icc. This seems to end up at a point in the
1229        generated configure script that is early enough to affect the setting of
1230        compiler options, which is what is needed, but I have no means of testing
1231        whether it really works. (The user who reported this had patched the
1232        generated configure script, which of course I cannot do.)
1234        LATER: After change 22 below (new libtool files), the configure script
1235        seems to know about icc (and also ecc). Therefore, I have commented out
1236        this hack in configure.in.
1238     7. Added support for pkg-config (2 patches were sent in).
1240     8. Negated POSIX character classes that used a combination of internal tables
1241        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1242        [[:^ascii]]. Typically, they would match almost any characters. The other
1243        POSIX classes were not broken in this way.
1245     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1246        to find the match, as PCRE was deluded into thinking that the match had to
1247        start at the start point or following a newline. The same bug applied to
1248        patterns with negative forward assertions or any backward assertions
1249        preceding ".*" at the start, unless the pattern required a fixed first
1250        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1252    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1253        starting at the last subject character, bytes beyond the end of the subject
1254        string were read.
1256    11. Renamed the variable "class" as "classbits" to make life easier for C++
1257        users. (Previously there was a macro definition, but it apparently wasn't
1258        enough.)
1260    12. Added the new field "tables" to the extra data so that tables can be passed
1261        in at exec time, or the internal tables can be re-selected. This allows
1262        a compiled regex to be saved and re-used at a later time by a different
1263        program that might have everything at different addresses.
1265    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1266        -R library as well as a -L library.
1268    14. The debugging options of pcretest (-d on the command line or D on a
1269        pattern) showed incorrect output for anything following an extended class
1270        that contained multibyte characters and which was followed by a quantifier.
1272    15. Added optional support for general category Unicode character properties
1273        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1274        support. It adds about 90K to the size of the library. The meanings of the
1275        inbuilt class escapes such as \d and \s have NOT been changed.
1277    16. Updated pcredemo.c to include calls to free() to release the memory for the
1278        compiled pattern.
1280    17. The generated file chartables.c was being created in the source directory
1281        instead of in the building directory. This caused the build to fail if the
1282        source directory was different from the building directory, and was
1283        read-only.
1285    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1286        file. No doubt somebody will tell me if they don't make sense... Also added
1287        Dan Mooney's comments about building on OpenVMS.
1289    19. Added support for partial matching via the PCRE_PARTIAL option for
1290        pcre_exec() and the \P data escape in pcretest.
1292    20. Extended pcretest with 3 new pattern features:
1294        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1295              write the compiled pattern to the file whose name is "rest-of-line".
1296              This is a straight binary dump of the data, with the saved pointer to
1297              the character tables forced to be NULL. The study data, if any, is
1298              written too. After writing, pcretest reads a new pattern.
1300        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1301              compiled pattern from the given file. There must not be any
1302              occurrences of "<" in the file name (pretty unlikely); if there are,
1303              pcretest will instead treat the initial "<" as a pattern delimiter.
1304              After reading in the pattern, pcretest goes on to read data lines as
1305              usual.
1307        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1308              and 16-bit fields in a compiled pattern, to simulate a pattern that
1309              was compiled on a host of opposite endianness.
1311    21. The pcre-exec() function can now cope with patterns that were compiled on
1312        hosts of opposite endianness, with this restriction:
1314          As for any compiled expression that is saved and used later, the tables
1315          pointer field cannot be preserved; the extra_data field in the arguments
1316          to pcre_exec() should be used to pass in a tables address if a value
1317          other than the default internal tables were used at compile time.
1319    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1320        now diagnosed as an error. Previously, most of the time, a negative number
1321        would have been treated as zero, but if in addition "ovector" was passed as
1322        NULL, a crash could occur.
1324    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1325        new versions from the libtool 1.5 distribution (the last one is a copy of
1326        a file called libtool.m4). This seems to have fixed the need to patch
1327        "configure" to support Darwin 1.3 (which I used to do). However, I still
1328        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1329        workstation).
1331    24. Changed the PCRE licence to be the more standard "BSD" licence.
1334    Version 4.5 01-Dec-03
1335    ---------------------
1337     1. There has been some re-arrangement of the code for the match() function so
1338        that it can be compiled in a version that does not call itself recursively.
1339        Instead, it keeps those local variables that need separate instances for
1340        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1341        needs to "recurse". Keeping track of where control must go is done by means
1342        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1343        hide most of the details from the main code, and operates only if
1344        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1345        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1346        operating.
1348        To make it easier for callers to provide specially tailored get/free
1349        functions for this usage, two new functions, pcre_stack_malloc, and
1350        pcre_stack_free, are used. They are always called in strict stacking order,
1351        and the size of block requested is always the same.
1353        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1354        PCRE has been compiled to use the stack or the heap for recursion. The
1355        -C option of pcretest uses this to show which version is compiled.
1357        A new data escape \S, is added to pcretest; it causes the amounts of store
1358        obtained and freed by both kinds of malloc/free at match time to be added
1359        to the output.
1361     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1362        what's available on my current Linux desktop machine.
1364     3. When matching a UTF-8 string, the test for a valid string at the start has
1365        been extended. If start_offset is not zero, PCRE now checks that it points
1366        to a byte that is the start of a UTF-8 character. If not, it returns
1367        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1368        this is necessary because there may be backward assertions in the pattern.
1369        When matching the same subject several times, it may save resources to use
1370        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1372     4. The code for checking the validity of UTF-8 strings has been tightened so
1373        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1374        containing "overlong sequences".
1376     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1377        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1378        should have been "&", but it just so happened that all the cases this let
1379        through by mistake were picked up later in the function.
1381     6. I had used a variable called "isblank" - this is a C99 function, causing
1382        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1384     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1385        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1386        so the version is shown; (c) stop "make test" echoing "./RunTest".
1388     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1390     9. The prototype for memmove() for systems that don't have it was using
1391        size_t, but the inclusion of the header that defines size_t was later. I've
1392        moved the #includes for the C headers earlier to avoid this.
1394    10. Added some adjustments to the code to make it easier to compiler on certain
1395        special systems:
1397          (a) Some "const" qualifiers were missing.
1398          (b) Added the macro EXPORT before all exported functions; by default this
1399              is defined to be empty.
1400          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1401              that it reads its output file name as an argument instead of writing
1402              to the standard output and assuming this can be redirected.
1404    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1405        class containing characters with values greater than 255, PCRE compilation
1406        went into a loop.
1408    12. A recursive reference to a subpattern that was within another subpattern
1409        that had a minimum quantifier of zero caused PCRE to crash. For example,
1410        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1411        recursion. If the recursively-called subpattern itself had a zero repeat,
1412        that was OK.
1414    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1415        buffer into which it was copied (for escape processing) was still set at
1416        1024, so long lines caused crashes.
1418    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1419        "internal error: code overflow...". This applied to any character class
1420        that was followed by a possessive quantifier.
1422    15. Modified the Makefile to add libpcre.la as a prerequisite for
1423        libpcreposix.la because I was told this is needed for a parallel build to
1424        work.
1426    16. If a pattern that contained .* following optional items at the start was
1427        studied, the wrong optimizing data was generated, leading to matching
1428        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1429        matching string must start with a or b or c. The correct conclusion for
1430        this pattern is that a match can start with any character.
1433    Version 4.4 13-Aug-03
1434    ---------------------
1436     1. In UTF-8 mode, a character class containing characters with values between
1437        127 and 255 was not handled correctly if the compiled pattern was studied.
1438        In fixing this, I have also improved the studying algorithm for such
1439        classes (slightly).
1441     2. Three internal functions had redundant arguments passed to them. Removal
1442        might give a very teeny performance improvement.
1444     3. Documentation bug: the value of the capture_top field in a callout is *one
1445        more than* the number of the hightest numbered captured substring.
1447     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1448        in incorrectly linking with a previously installed version. They now link
1449        explicitly with libpcre.la.
1451     5. configure.in no longer needs to recognize Cygwin specially.
1453     6. A problem in pcre.in for Windows platforms is fixed.
1455     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1456        pcretest, it used to include the size of the study block as part of its
1457        output. Unfortunately, the structure contains a field that has a different
1458        size on different hardware architectures. This meant that the tests that
1459        showed this size failed. As the block is currently always of a fixed size,
1460        this information isn't actually particularly useful in pcretest output, so
1461        I have just removed it.
1463     8. Three pre-processor statements accidentally did not start in column 1.
1464        Sadly, there are *still* compilers around that complain, even though
1465        standard C has not required this for well over a decade. Sigh.
1467     9. In pcretest, the code for checking callouts passed small integers in the
1468        callout_data field, which is a void * field. However, some picky compilers
1469        complained about the casts involved for this on 64-bit systems. Now
1470        pcretest passes the address of the small integer instead, which should get
1471        rid of the warnings.
1473    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1474        both compile and run time, and gives an error if an invalid UTF-8 sequence
1475        is found. There is a option for disabling this check in cases where the
1476        string is known to be correct and/or the maximum performance is wanted.
1478    11. In response to a bug report, I changed one line in Makefile.in from
1480            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1481        to
1482            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1484        to look similar to other lines, but I have no way of telling whether this
1485        is the right thing to do, as I do not use Windows. No doubt I'll get told
1486        if it's wrong...
1489    Version 4.3 21-May-03
1490    ---------------------
1492    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1493       Makefile.
1495    2. Some refactoring to improve the quality of the code:
1497       (i)   The utf8_table... variables are now declared "const".
1499       (ii)  The code for \cx, which used the "case flipping" table to upper case
1500             lower case letters, now just substracts 32. This is ASCII-specific,
1501             but the whole concept of \cx is ASCII-specific, so it seems
1502             reasonable.
1504       (iii) PCRE was using its character types table to recognize decimal and
1505             hexadecimal digits in the pattern. This is silly, because it handles
1506             only 0-9, a-f, and A-F, but the character types table is locale-
1507             specific, which means strange things might happen. A private
1508             table is now used for this - though it costs 256 bytes, a table is
1509             much faster than multiple explicit tests. Of course, the standard
1510             character types table is still used for matching digits in subject
1511             strings against \d.
1513       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1514             ending in _t are). So I've renamed it as ESC_tee.
1516    3. The first argument for regexec() in the POSIX wrapper should have been
1517       defined as "const".
1519    4. Changed pcretest to use malloc() for its buffers so that they can be
1520       Electric Fenced for debugging.
1522    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1523       to read one or more bytes before the start of the subject string. Often this
1524       had no effect on PCRE's behaviour, but in some circumstances it could
1525       provoke a segmentation fault.
1527    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1528       to try to read one or more bytes before the start of the subject string.
1530    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1531       UTF-8 support could misbehave in various ways if the subject string
1532       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1533       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1534       back over UTF-8 characters.)
1537    Version 4.2 14-Apr-03
1538    ---------------------
1540    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1542    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1543         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1544         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1545         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1546         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1547           and BUILD_EXEEXT
1548         Note: automatic setting of the BUILD variables is not yet working
1549         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1550           compile-time but not at link-time
1551         [LINK]: use for linking executables only
1552         make different versions for Windows and non-Windows
1553         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1554           libraries
1555         [LINK_FOR_BUILD]: new variable
1556         [OBJEXT]: use throughout
1557         [EXEEXT]: use throughout
1558         <winshared>: new target
1559         <wininstall>: new target
1560         <dftables.o>: use native compiler
1561         <dftables>: use native linker
1562         <install>: handle Windows platform correctly
1563         <clean>: ditto
1564         <check>: ditto
1565         copy DLL to top builddir before testing
1567       As part of these changes, -no-undefined was removed again. This was reported
1568       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1569       in any case.
1571    3. Some tidies to get rid of compiler warnings:
1573       . In the match_data structure, match_limit was an unsigned long int, whereas
1574         match_call_count was an int. I've made them both unsigned long ints.
1576       . In pcretest the fact that a const uschar * doesn't automatically cast to
1577         a void * provoked a warning.
1579       . Turning on some more compiler warnings threw up some "shadow" variables
1580         and a few more missing casts.
1582    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1583       option, a class that contained a single character with a value between 128
1584       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1586    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1587       option, a class that contained several characters, but with at least one
1588       whose value was between 128 and 255 caused PCRE to crash.
1591    Version 4.1 12-Mar-03
1592    ---------------------
1594    1. Compiling with gcc -pedantic found a couple of places where casts were
1595    needed, and a string in dftables.c that was longer than standard compilers are
1596    required to support.
1598    2. Compiling with Sun's compiler found a few more places where the code could
1599    be tidied up in order to avoid warnings.
1601    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1602    first of these names is deprecated in the latest Autoconf in favour of the name
1603    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1604    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1605    analogy I have changed it to CFLAGS_FOR_BUILD.
1607    4. Added -no-undefined to the linking command in the Makefile, because this is
1608    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1609    linking step for the pcreposix library.
1611    5. PCRE was failing to diagnose the case of two named groups with the same
1612    name.
1614    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1615    literal character that is needed in the subject for a match, and scans along to
1616    ensure that it is present before embarking on the full matching process. This
1617    saves time in cases of nested unlimited repeats that are never going to match.
1618    Problem: the scan can take a lot of time if the subject is very long (e.g.
1619    megabytes), thus penalizing straightforward matches. It is now done only if the
1620    amount of subject to be scanned is less than 1000 bytes.
1622    7. A lesser problem with the same optimization is that it was recording the
1623    first character of an anchored pattern as "needed", thus provoking a search
1624    right along the subject, even when the first match of the pattern was going to
1625    fail. The "needed" character is now not set for anchored patterns, unless it
1626    follows something in the pattern that is of non-fixed length. Thus, it still
1627    fulfils its original purpose of finding quick non-matches in cases of nested
1628    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1631    Version 4.0 17-Feb-03
1632    ---------------------
1634    1. If a comment in an extended regex that started immediately after a meta-item
1635    extended to the end of string, PCRE compiled incorrect data. This could lead to
1636    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1638    2. Moved to autoconf 2.53 and libtool 1.4.2.
1640    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1641    the special perltest8 script is no longer needed - all the tests can be run
1642    from a single perltest script.
1644    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1645    by \s. It has now been removed in PCRE. This means it isn't recognized as
1646    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1647    class [:space:] *does* include VT, thereby creating a mess.
1649    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1650    space and tab.
1652    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1653    its new features into the main test script, reducing the number of scripts.
1655    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1656    were backward compatible, and made the (?i) apply to the whole pattern, as if
1657    /i were given. Now it behaves more logically, and applies the option setting
1658    only to what follows. PCRE has been changed to follow suit. However, if it
1659    finds options settings right at the start of the pattern, it extracts them into
1660    the global options, as before. Thus, they show up in the info data.
1662    8. Added support for the \Q...\E escape sequence. Characters in between are
1663    treated as literals. This is slightly different from Perl in that $ and @ are
1664    also handled as literals inside the quotes. In Perl, they will cause variable
1665    interpolation. Note the following examples:
1667        Pattern            PCRE matches      Perl matches
1669        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1670        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1671        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1673    For compatibility with Perl, \Q...\E sequences are recognized inside character
1674    classes as well as outside them.
1676    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1677    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1678    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1679    signed/unsigned warnings.
1681    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1682    option for pcretest, so I've replaced it by a simple function that does just
1683    that job.
1685    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1686    "pcregrep -".
1688    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1689    Java package. This provides some syntactic sugar for simple cases of what my
1690    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1691    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1692    item, you can use this simplified notation. Note that only makes sense with
1693    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1694    greediness, whatever the setting of the PCRE_UNGREEDY option.
1696    13. A change of greediness default within a pattern was not taking effect at
1697    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1698    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1699    was abstracted outside.
1701    14. PCRE now supports the \G assertion. It is true when the current matching
1702    position is at the start point of the match. This differs from \A when the
1703    starting offset is non-zero. Used with the /g option of pcretest (or similar
1704    code), it works in the same way as it does for Perl's /g option. If all
1705    alternatives of a regex begin with \G, the expression is anchored to the start
1706    match position, and the "anchored" flag is set in the compiled expression.
1708    15. Some bugs concerning the handling of certain option changes within patterns
1709    have been fixed. These applied to options other than (?ims). For example,
1710    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1711    been the other way round. Some of this was related to change 7 above.
1713    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1714    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1715    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1716    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1718    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1719    mode. Unlike ".", it always matches newline, whatever the setting of
1720    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1721    assertions. Perl allows it, but it doesn't (in general) work because it can't
1722    calculate the length of the lookbehind. At least, that's the case for Perl
1723    5.8.0 - I've been told they are going to document that it doesn't work in
1724    future.
1726    18. Added an error diagnosis for escapes that PCRE does not support: these are
1727    \L, \l, \N, \P, \p, \U, \u, and \X.
1729    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1730    reading past the end of the pattern in cases such as /[abcd/.
1732    20. PCRE was getting more memory than necessary for patterns with classes that
1733    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1735    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1736    compiling PCRE for use with Virtual Pascal.
1738    22. Small fix to the Makefile to make it work properly if the build is done
1739    outside the source tree.
1741    23. Added a new extension: a condition to go with recursion. If a conditional
1742    subpattern starts with (?(R) the "true" branch is used if recursion has
1743    happened, whereas the "false" branch is used only at the top level.
1745    24. When there was a very long string of literal characters (over 255 bytes
1746    without UTF support, over 250 bytes with UTF support), the computation of how
1747    much memory was required could be incorrect, leading to segfaults or other
1748    strange effects.
1750    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1751    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1752    there was a subsequent back reference to those brackets. This meant that, for
1753    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1754    possible to check for precisely this case. All we can do is abandon the
1755    optimization if .* occurs inside capturing brackets when there are any back
1756    references whatsoever. (See below for a better fix that came later.)
1758    26. The handling of the optimization for finding the first character of a
1759    non-anchored pattern, and for finding a character that is required later in the
1760    match were failing in some cases. This didn't break the matching; it just
1761    failed to optimize when it could. The way this is done has been re-implemented.
1763    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1765    28. Added a new feature that provides some of the functionality that Perl
1766    provides with (?{...}). The facility is termed a "callout". The way it is done
1767    in PCRE is for the caller to provide an optional function, by setting
1768    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1769    global variable. By default it is unset, which disables all calling out. To get
1770    the function called, the regex must include (?C) at appropriate points. This
1771    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1772    This provides a means of identifying different callout points. When PCRE
1773    reaches such a point in the regex, if pcre_callout has been set, the external
1774    function is called. It is provided with data in a structure called
1775    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1776    matching continues; if it returns a non-zero value, the match at the current
1777    point fails. However, backtracking will occur if possible. [This was changed
1778    later and other features added - see item 49 below.]
1780    29. pcretest is upgraded to test the callout functionality. It provides a
1781    callout function that displays information. By default, it shows the start of
1782    the match and the current position in the text. There are some new data escapes
1783    to vary what happens:
1785        \C+         in addition, show current contents of captured substrings
1786        \C-         do not supply a callout function
1787        \C!n        return 1 when callout number n is reached
1788        \C!n!m      return 1 when callout number n is reached for the mth time
1790    30. If pcregrep was called with the -l option and just a single file name, it
1791    output "<stdin>" if a match was found, instead of the file name.
1793    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1794    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1795    pcre_exec(). This saves a malloc/free per call. The default value of
1796    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1797    when configuring.
1799    32. The default maximum size of a compiled pattern is 64K. There have been a
1800    few cases of people hitting this limit. The code now uses macros to handle the
1801    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1802    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1803    configuring. Tests 2 and 5 work only with 2-byte links because they output
1804    debugging information about compiled patterns.
1806    33. Internal code re-arrangements:
1808    (a) Moved the debugging function for printing out a compiled regex into
1809        its own source file (printint.c) and used #include to pull it into
1810        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1811        separate copies.
1813    (b) Defined the list of op-code names for debugging as a macro in
1814        internal.h so that it is next to the definition of the opcodes.
1816    (c) Defined a table of op-code lengths for simpler skipping along compiled
1817        code. This is again a macro in internal.h so that it is next to the
1818        definition of the opcodes.
1820    34. Added support for recursive calls to individual subpatterns, along the
1821    lines of Robin Houston's patch (but implemented somewhat differently).
1823    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1824    allow it to read and process whole directories in Win32. This code was
1825    contributed by Lionel Fourquaux; it has not been tested by me.
1827    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1828    used to name a group. Names consist of alphanumerics and underscores, and must
1829    be unique. Back references use the syntax (?P=name) and recursive calls use
1830    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1831    numbers. The function pcre_fullinfo() can be used after compilation to extract
1832    a name/number map. There are three relevant calls:
1834      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1835      PCRE_INFO_NAMECOUNT            yields the number of entries
1836      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1838    The map is a vector of fixed-size entries. The size of each entry depends on
1839    the length of the longest name used. The first two bytes of each entry are the
1840    group number, most significant byte first. There follows the corresponding
1841    name, zero terminated. The names are in alphabetical order.
1843    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1844    case instead of 255. Making it the same both with and without UTF-8 support
1845    means that the same test output works with both.
1847    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1848    calling malloc() with a zero argument.
1850    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1851    optimization. I've improved things by keeping a bitmap of backreferences with
1852    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1853    fact referenced, the optimization can be applied. It is unlikely that a
1854    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1855    the match to follow \n) will appear inside brackets with a number greater than
1856    31, but if it does, any back reference > 31 suppresses the optimization.
1858    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1859    of disabling numbered capturing parentheses. Any opening parenthesis that is
1860    not followed by ? behaves as if it were followed by ?: but named parentheses
1861    can still be used for capturing (and they will acquire numbers in the usual
1862    way).
1864    41. Redesigned the return codes from the match() function into yes/no/error so
1865    that errors can be passed back from deep inside the nested calls. A malloc
1866    failure while inside a recursive subpattern call now causes the
1867    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1869    42. It is now possible to set a limit on the number of times the match()
1870    function is called in a call to pcre_exec(). This facility makes it possible to
1871    limit the amount of recursion and backtracking, though not in a directly
1872    obvious way, because the match() function is used in a number of different
1873    circumstances. The count starts from zero for each position in the subject
1874    string (for non-anchored patterns). The default limit is, for compatibility, a
1875    large number, namely 10 000 000. You can change this in two ways:
1877    (a) When configuring PCRE before making, you can use --with-match-limit=n
1878        to set a default value for the compiled library.
1880    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1881        a different value is set. See 45 below.
1883    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1885    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1886    of things that can be changed at compile time. The first argument specifies
1887    what is wanted and the second points to where the information is to be placed.
1888    The current list of available information is:
1890      PCRE_CONFIG_UTF8
1892    The output is an integer that is set to one if UTF-8 support is available;
1893    otherwise it is set to zero.
1897    The output is an integer that it set to the value of the code that is used for
1898    newline. It is either LF (10) or CR (13).
1902    The output is an integer that contains the number of bytes used for internal
1903    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1907    The output is an integer that contains the threshold above which the POSIX
1908    interface uses malloc() for output vectors. See item 31 above.
1912    The output is an unsigned integer that contains the default limit of the number
1913    of match() calls in a pcre_exec() execution. See 42 above.
1915    44. pcretest has been upgraded by the addition of the -C option. This causes it
1916    to extract all the available output from the new pcre_config() function, and to
1917    output it. The program then exits immediately.
1919    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1920    order to support additional features. One way would have been to define
1921    pcre_exec2() (for example) with extra arguments, but this would not have been
1922    extensible, and would also have required all calls to the original function to
1923    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1924    is used for passing in "extra" data from pcre_study().
1926    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1927    contains the following fields:
1929      flags         a bitmap indicating which of the following fields are set
1930      study_data    opaque data from pcre_study()
1931      match_limit   a way of specifying a limit on match() calls for a specific
1932                      call to pcre_exec()
1933      callout_data  data for callouts (see 49 below)
1935    The flag bits are also defined in pcre.h, and are
1941    The pcre_study() function now returns one of these new pcre_extra blocks, with
1942    the actual study data pointed to by the study_data field, and the
1943    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1944    before. That is, this change is entirely upwards-compatible and requires no
1945    change to existing code.
1947    If you want to pass in additional data to pcre_exec(), you can either place it
1948    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1949    block.
1951    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1952    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1953    times with different match limits, until it finds the minimum value needed for
1954    pcre_exec() to complete. The value is then output. This can be instructive; for
1955    most simple matches the number is quite small, but for pathological cases it
1956    gets very large very quickly.
1958    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1959    returns the size of the data block pointed to by the study_data field in a
1960    pcre_extra block, that is, the value that was passed as the argument to
1961    pcre_malloc() when PCRE was getting memory in which to place the information
1962    created by pcre_study(). The fourth argument should point to a size_t variable.
1963    pcretest has been extended so that this information is shown after a successful
1964    pcre_study() call when information about the compiled regex is being displayed.
1966    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1967    because what follows is always an absolute path. (Later: it turns out that this
1968    is more than cosmetic for MinGW, because it doesn't like empty path
1969    components.)
1971    49. Some changes have been made to the callout feature (see 28 above):
1973    (i)  A callout function now has three choices for what it returns:
1975           0  =>  success, carry on matching
1976         > 0  =>  failure at this point, but backtrack if possible
1977         < 0  =>  serious error, return this value from pcre_exec()
1979         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1980         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1981         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1982         use by callout functions. It will never be used by PCRE itself.
1984    (ii) The pcre_extra structure (see 45 above) has a void * field called
1985         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1986         pcre_callout_block structure has a field of the same name. The contents of
1987         the field passed in the pcre_extra structure are passed to the callout
1988         function in the corresponding field in the callout block. This makes it
1989         easier to use the same callout-containing regex from multiple threads. For
1990         testing, the pcretest program has a new data escape
1992           \C*n        pass the number n (may be negative) as callout_data
1994         If the callout function in pcretest receives a non-zero value as
1995         callout_data, it returns that value.
1997    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1998    there were some redundant $(CFLAGS) in commands that are now specified as
1999    $(LINK), which already includes $(CFLAGS).
2001    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2002    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2003    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2004    one-byte characters throughout. Note that case-insensitive matching applies
2005    only to characters whose values are less than 256. PCRE doesn't support the
2006    notion of cases for higher-valued characters.
2008    (i)   A character class whose characters are all within 0-255 is handled as
2009          a bit map, and the map is inverted for negative classes. Previously, a
2010          character > 255 always failed to match such a class; however it should
2011          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2013    (ii)  A negated character class with a single character < 255 is coded as
2014          "not this character" (OP_NOT). This wasn't working properly when the test
2015          character was multibyte, either singly or repeated.
2017    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2018          mode, for example: \x{100}{2,3}.
2020    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2021          singly or repeated) now correctly test multibyte characters. However,
2022          PCRE doesn't recognize any characters with values greater than 255 as
2023          digits, spaces, or word characters. Such characters always match \D, \S,
2024          and \W, and never match \d, \s, or \w.
2026    (v)   Classes may now contain characters and character ranges with values
2027          greater than 255. For example: [ab\x{100}-\x{400}].
2029    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2030          PCRE in UTF-8 mode.
2032    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2033    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2034    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2035    value.)
2037    53. The single man page has become too large. I have therefore split it up into
2038    a number of separate man pages. These also give rise to individual HTML pages;
2039    these are now put in a separate directory, and there is an index.html page that
2040    lists them all. Some hyperlinking between the pages has been installed.
2042    54. Added convenience functions for handling named capturing parentheses.
2044    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2045    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2046    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2047    are faulted.
2049    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2050    calling configure. These values are used when compiling the dftables.c program
2051    which is run to generate the source of the default character tables. They
2052    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2053    you will need to set these values.
2055    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2058    Version 3.9 02-Jan-02
2059    ---------------------
2061    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2063    2. If --disable-static was given, the building process failed when trying to
2064    build pcretest and pcregrep. (For some reason it was using libtool to compile
2065    them, which is not right, as they aren't part of the library.)
2068    Version 3.8 18-Dec-01
2069    ---------------------
2071    1. The experimental UTF-8 code was completely screwed up. It was packing the
2072    bytes in the wrong order. How dumb can you get?
2075    Version 3.7 29-Oct-01
2076    ---------------------
2078    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2079    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2080    this didn't happen under Solaris 8, where I normally test things.
2082    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2083    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2084    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2085    this fix an hour or so after the initial 3.7 release.)
2088    Version 3.6 23-Oct-01
2089    ---------------------
2091    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2092    offsets passed as NULL with zero offset count.
2094    2. The config.guess and config.sub files had not been updated when I moved to
2095    the latest autoconf.
2098    Version 3.5 15-Aug-01
2099    ---------------------
2101    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2102    had been forgotten.
2104    2. By using declared but undefined structures, we can avoid using "void"
2105    definitions in pcre.h while keeping the internal definitions of the structures
2106    private.
2108    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2109    user point of view, this means that both static and shared libraries are built
2110    by default, but this can be individually controlled. More of the work of
2111    handling this static/shared cases is now inside libtool instead of PCRE's make
2112    file.
2114    4. The pcretest utility is now installed along with pcregrep because it is
2115    useful for users (to test regexs) and by doing this, it automatically gets
2116    relinked by libtool. The documentation has been turned into a man page, so
2117    there are now .1, .txt, and .html versions in /doc.
2119    5. Upgrades to pcregrep:
2120       (i)   Added long-form option names like gnu grep.
2121       (ii)  Added --help to list all options with an explanatory phrase.
2122       (iii) Added -r, --recursive to recurse into sub-directories.
2123       (iv)  Added -f, --file to read patterns from a file.
2125    6. pcre_exec() was referring to its "code" argument before testing that
2126    argument for NULL (and giving an error if it was NULL).
2128    7. Upgraded Makefile.in to allow for compiling in a different directory from
2129    the source directory.
2131    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2132    options bits, the pointer it was passed was to an int instead of to an unsigned
2133    long int. This mattered only on 64-bit systems.
2135    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2136    generated) instead of pcre.in, which it its source. Also made the same change
2137    in several of the .c files.
2139    10. A new release of gcc defines printf() as a macro, which broke pcretest
2140    because it had an ifdef in the middle of a string argument for printf(). Fixed
2141    by using separate calls to printf().
2143    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2144    script, to force use of CR or LF instead of \n in the source. On non-Unix
2145    systems, the value can be set in config.h.
2147    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2148    absolute limit. Changed the text of the error message to make this clear, and
2149    likewise updated the man page.
2151    13. The limit of 99 on the number of capturing subpatterns has been removed.
2152    The new limit is 65535, which I hope will not be a "real" limit.
2155    Version 3.4 22-Aug-00
2156    ---------------------
2158    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2160    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2163    Version 3.3 01-Aug-00
2164    ---------------------
2166    1. If an octal character was given, but the value was greater than \377, it
2167    was not getting masked to the least significant bits, as documented. This could
2168    lead to crashes in some systems.
2170    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2171    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2173    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2174    These just pass their arguments on to (pcre_free)(), but they are provided
2175    because some uses of PCRE bind it to non-C systems that can call its functions,
2176    but cannot call free() or pcre_free() directly.
2178    4. Add "make test" as a synonym for "make check". Corrected some comments in
2179    the Makefile.
2181    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2182    Makefile.
2184    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2185    command called pgrep for grepping around the active processes.
2187    7. Added the beginnings of support for UTF-8 character strings.
2189    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2190    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2191    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2192    out for the ar command.)
2195    Version 3.2 12-May-00
2196    ---------------------
2198    This is purely a bug fixing release.
2200    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2201    of ZA. This was just one example of several cases that could provoke this bug,
2202    which was introduced by change 9 of version 2.00. The code for breaking
2203    infinite loops after an iteration that matches an empty string was't working
2204    correctly.
2206    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2207    when matched against abbab (for example). After matching an empty string, it
2208    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2209    caused it to match further down the string than it should.
2211    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2212    was there because it doesn't seem to be needed, and it causes trouble on some
2213    systems, as it is not a Standard C header. It has been removed.
2215    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2216    were reported on the Macintosh. The changes were from
2218      while ((c = *(++ptr)) != 0 && c != '\n');
2219    to
2220      while ((c = *(++ptr)) != 0 && c != '\n') ;
2222    Totally extraordinary, but if that's what it takes...
2224    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2225    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2226    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2227    assumes the way PCRE uses memmove() (always moving upwards).
2229    6. PCRE is being used in one environment where strchr() is not available. There
2230    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2231    faster code anyway.
2234    Version 3.1 09-Feb-00
2235    ---------------------
2237    The only change in this release is the fixing of some bugs in Makefile.in for
2238    the "install" target:
2240    (1) It was failing to install pcreposix.h.
2242    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2245    Version 3.0 01-Feb-00
2246    ---------------------
2248    1. Add support for the /+ modifier to perltest (to output $` like it does in
2249    pcretest).
2251    2. Add support for the /g modifier to perltest.
2253    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2254    matches null strings.
2256    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2257    pattern. Perl treats empty patterns specially - it reuses the most recent
2258    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2259    effect.
2261    5. The POSIX interface was broken in that it was just handing over the POSIX
2262    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2263    required a bigger vector, with some working space on the end. This means that
2264    the POSIX wrapper now has to get and free some memory, and copy the results.
2266    6. Added some simple autoconf support, placing the test data and the
2267    documentation in separate directories, re-organizing some of the
2268    information files, and making it build pcre-config (a GNU standard). Also added
2269    libtool support for building PCRE as a shared library, which is now the
2270    default.
2272    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2273    09 are not valid octal constants. Single digits will be used for minor values
2274    less than 10.
2276    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2277    existing programs that set these in the POSIX interface can use PCRE without
2278    modification.
2280    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2281    return all that pcre_info() returns, plus additional data. The pcre_info()
2282    function is retained for compatibility, but is considered to be obsolete.
2284    10. Added experimental recursion feature (?R) to handle one common case that
2285    Perl 5.6 will be able to do with (?p{...}).
2287    11. Added support for POSIX character classes like [:alpha:], which Perl is
2288    adopting.
2291    Version 2.08 31-Aug-99
2292    ----------------------
2294    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2295    trying to match at the startoffset position, but instead was moving forward to
2296    the next newline as if a previous match had failed.
2298    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2299    and could get into a loop if a null string was matched other than at the start
2300    of the subject.
2302    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2303    be distinguished at compile time, and for completeness also added PCRE_DATE.
2305    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2306    in GnuWin32 environments.
2309    Version 2.07 29-Jul-99
2310    ----------------------
2312    1. The documentation is now supplied in plain text form and HTML as well as in
2313    the form of man page sources.
2315    2. C++ compilers don't like assigning (void *) values to other pointer types.
2316    In particular this affects malloc(). Although there is no problem in Standard
2317    C, I've put in casts to keep C++ compilers happy.
2319    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2320    should be (const char *).
2322    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2323    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2324    However, I haven't made this a standard facility. The documentation doesn't
2325    mention it, and the Makefile doesn't support it.
2327    5. The Makefile now contains an "install" target, with editable destinations at
2328    the top of the file. The pcretest program is not installed.
2330    6. pgrep -V now gives the PCRE version number and date.
2332    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2333    causing the entire string to be ignored, instead of just the last character.
2335    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2336    non-matching string, it can take a very, very long time, even for strings of
2337    quite modest length, because of the nested recursion. PCRE now does better in
2338    some of these cases. It does this by remembering the last required literal
2339    character in the pattern, and pre-searching the subject to ensure it is present
2340    before running the real match. In other words, it applies a heuristic to detect
2341    some types of certain failure quickly, and in the above example, if presented
2342    with a string that has no trailing " it gives "no match" very quickly.
2344    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2345    other alternatives are tried instead.
2348    Version 2.06 09-Jun-99
2349    ----------------------
2351    1. Change pcretest's output for amount of store used to show just the code
2352    space, because the remainder (the data block) varies in size between 32-bit and
2353    64-bit systems.
2355    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2356    start matching at. This allows lookbehinds to work when searching for multiple
2357    occurrences in a string.
2359    3. Added additional options to pcretest for testing multiple occurrences:
2361       /+   outputs the rest of the string that follows a match
2362       /g   loops for multiple occurrences, using the new startoffset argument
2363       /G   loops for multiple occurrences by passing an incremented pointer
2365    4. PCRE wasn't doing the "first character" optimization for patterns starting
2366    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2367    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2368    the letter 'x'. On long subject strings, this gives a significant speed-up.
2371    Version 2.05 21-Apr-99
2372    ----------------------
2374    1. Changed the type of magic_number from int to long int so that it works
2375    properly on 16-bit systems.
2377    2. Fixed a bug which caused patterns starting with .* not to work correctly
2378    when the subject string contained newline characters. PCRE was assuming
2379    anchoring for such patterns in all cases, which is not correct because .* will
2380    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2381    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2382    must be retried after every newline in the subject.
2385    Version 2.04 18-Feb-99
2386    ----------------------
2388    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2389    computation of the store needed to hold the pattern was incorrect (too large).
2390    If such patterns were nested a few deep, this could multiply and become a real
2391    problem.
2393    2. Added /M option to pcretest to show the memory requirement of a specific
2394    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2396    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2397    compiled in such a way that the backtracking after subsequent failure was
2398    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2399    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2402    Version 2.03 02-Feb-99
2403    ----------------------
2405    1. Fixed typo and small mistake in man page.
2407    2. Added 4th condition (GPL supersedes if conflict) and created separate
2408    LICENCE file containing the conditions.
2410    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2411    Perl, that is the internal \ allows the delimiter to be included in the
2412    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2413    the final delimiter, add \ to the end of the pattern (to test the error).
2415    4. Added the convenience functions for extracting substrings after a successful
2416    match. Updated pcretest to make it able to test these functions.
2419  Version 2.02 14-Jan-99  Version 2.02 14-Jan-99
2420  ----------------------  ----------------------

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