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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.1 05-Mar-07
5    ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The maintain/132html script that I use to
25        generate HTML has been updated to handle .nf/.fi and to complain if it
26        encounters .br or .in.
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, for the benefit
30        of those who have to compile without Autotools (compare pcre.h).
32     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
33        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
34        makevp.bat for the current PCRE, using the additional files !compile.txt,
35        !linklib.txt, and pcregexp.pas.
37     6. A Windows user reported a minor discrepancy with test 2, which turned out
38        to be caused by a trailing space on an input line that had got lost in his
39        copy. The trailing space was an accident, so I've just removed it.
41     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
42        that is needed.
44     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
45        as "const" (a) because they are and (b) because it helps the PHP
46        maintainers who have recently made a script to detect big data structures
47        in the php code that should be moved to the .rodata section. I remembered
48        to update Builducptable as well, so it won't revert if ucptable.h is ever
49        re-created.
51     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
52        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
53        order to be able to cut out the UTF-8 tables in the latter when UTF-8
54        support is not required. This saves 1.5-2K of code, which is important in
55        some applications.
58    Version 7.0 19-Dec-06
59    ---------------------
61     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
62        moving to gcc 4.1.1.
64     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
65        sys/time.h, which is documented as needed for this function. It doesn't
66        seem to matter on Linux, but it showed up on some releases of OS X.
68     3. It seems that there are systems where bytes whose values are greater than
69        127 match isprint() in the "C" locale. The "C" locale should be the
70        default when a C program starts up. In most systems, only ASCII printing
71        characters match isprint(). This difference caused the output from pcretest
72        to vary, making some of the tests fail. I have changed pcretest so that:
74        (a) When it is outputting text in the compiled version of a pattern, bytes
75            other than 32-126 are always shown as hex escapes.
77        (b) When it is outputting text that is a matched part of a subject string,
78            it does the same, unless a different locale has been set for the match
79            (using the /L modifier). In this case, it uses isprint() to decide.
81     4. Fixed a major bug that caused incorrect computation of the amount of memory
82        required for a compiled pattern when options that changed within the
83        pattern affected the logic of the preliminary scan that determines the
84        length. The relevant options are -x, and -i in UTF-8 mode. The result was
85        that the computed length was too small. The symptoms of this bug were
86        either the PCRE error "internal error: code overflow" from pcre_compile(),
87        or a glibc crash with a message such as "pcretest: free(): invalid next
88        size (fast)". Examples of patterns that provoked this bug (shown in
89        pcretest format) are:
91          /(?-x: )/x
92          /(?x)(?-x: \s*#\s*)/
93          /((?i)[\x{c0}])/8
94          /(?i:[\x{c0}])/8
96        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
97        is now done differently.
99     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
100        wrapper classes; (b) implement a new function in the C++ scanner that is
101        more efficient than the old way of doing things because it avoids levels of
102        recursion in the regex matching; (c) add a paragraph to the documentation
103        for the FullMatch() function.
105     6. The escape sequence \n was being treated as whatever was defined as
106        "newline". Not only was this contrary to the documentation, which states
107        that \n is character 10 (hex 0A), but it also went horribly wrong when
108        "newline" was defined as CRLF. This has been fixed.
110     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
111        was being set to -1 for the "end of line" case (supposedly a value that no
112        character can have). Though this value is never used (the check for end of
113        line is "zero bytes in current character"), it caused compiler complaints.
114        I've changed it to 0xffffffff.
116     8. In pcre_version.c, the version string was being built by a sequence of
117        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
118        string (as it is for production releases) called a macro with an empty
119        argument. The C standard says the result of this is undefined. The gcc
120        compiler treats it as an empty string (which was what was wanted) but it is
121        reported that Visual C gives an error. The source has been hacked around to
122        avoid this problem.
124     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
125        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
126        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
127        of them did).
129    10. Originally, pcretest opened its input and output without "b"; then I was
130        told that "b" was needed in some environments, so it was added for release
131        5.0 to both the input and output. (It makes no difference on Unix-like
132        systems.) Later I was told that it is wrong for the input on Windows. I've
133        now abstracted the modes into two macros, to make it easier to fiddle with
134        them, and removed "b" from the input mode under Windows.
136    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
138    12. Added -help and --help to pcretest as an official way of being reminded
139        of the options.
141    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
142        and pcrecpp.cc because they annoy compilers at high warning levels.
144    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
146    15. Fixed an occurrence of == in configure.ac that should have been = (shell
147        scripts are not C programs :-) and which was not noticed because it works
148        on Linux.
150    16. pcretest is supposed to handle any length of pattern and data line (as one
151        line or as a continued sequence of lines) by extending its input buffer if
152        necessary. This feature was broken for very long pattern lines, leading to
153        a string of junk being passed to pcre_compile() if the pattern was longer
154        than about 50K.
156    17. I have done a major re-factoring of the way pcre_compile() computes the
157        amount of memory needed for a compiled pattern. Previously, there was code
158        that made a preliminary scan of the pattern in order to do this. That was
159        OK when PCRE was new, but as the facilities have expanded, it has become
160        harder and harder to keep it in step with the real compile phase, and there
161        have been a number of bugs (see for example, 4 above). I have now found a
162        cunning way of running the real compile function in a "fake" mode that
163        enables it to compute how much memory it would need, while actually only
164        ever using a few hundred bytes of working memory and without too many
165        tests of the mode. This should make future maintenance and development
166        easier. A side effect of this work is that the limit of 200 on the nesting
167        depth of parentheses has been removed (though this was never a serious
168        limitation, I suspect). However, there is a downside: pcre_compile() now
169        runs more slowly than before (30% or more, depending on the pattern). I
170        hope this isn't a big issue. There is no effect on runtime performance.
172    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
173        newline (only possible for the last line of a file) and it was a
174        pattern that set a locale (followed by /Lsomething), pcretest crashed.
176    19. Added additional timing features to pcretest. (1) The -tm option now times
177        matching only, not compiling. (2) Both -t and -tm can be followed, as a
178        separate command line item, by a number that specifies the number of
179        repeats to use when timing. The default is 50000; this gives better
180        precision, but takes uncomfortably long for very large patterns.
182    20. Extended pcre_study() to be more clever in cases where a branch of a
183        subpattern has no definite first character. For example, (a*|b*)[cd] would
184        previously give no result from pcre_study(). Now it recognizes that the
185        first character must be a, b, c, or d.
187    21. There was an incorrect error "recursive call could loop indefinitely" if
188        a subpattern (or the entire pattern) that was being tested for matching an
189        empty string contained only one non-empty item after a nested subpattern.
190        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
191        incorrectly, because the \d was being skipped in the check.
193    22. The pcretest program now has a new pattern option /B and a command line
194        option -b, which is equivalent to adding /B to every pattern. This causes
195        it to show the compiled bytecode, without the additional information that
196        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
197        is the same as /B/I).
199    23. A new optimization is now able automatically to treat some sequences such
200        as a*b as a*+b. More specifically, if something simple (such as a character
201        or a simple class like \d) has an unlimited quantifier, and is followed by
202        something that cannot possibly match the quantified thing, the quantifier
203        is automatically "possessified".
205    24. A recursive reference to a subpattern whose number was greater than 39
206        went wrong under certain circumstances in UTF-8 mode. This bug could also
207        have affected the operation of pcre_study().
209    25. Realized that a little bit of performance could be had by replacing
210        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
212    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
214    27. Possessive quantifiers such as a++ were previously implemented by turning
215        them into atomic groups such as ($>a+). Now they have their own opcodes,
216        which improves performance. This includes the automatically created ones
217        from 23 above.
219    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
220        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
221        the first matched character to be a colon. This applied both to named and
222        numbered groups.
224    29. The ucpinternal.h header file was missing its idempotency #ifdef.
226    30. I was sent a "project" file called libpcre.a.dev which I understand makes
227        building PCRE on Windows easier, so I have included it in the distribution.
229    31. There is now a check in pcretest against a ridiculously large number being
230        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
231        loop, the loop is abandoned.
233    32. Forward references to subpatterns in conditions such as (?(2)...) where
234        subpattern 2 is defined later cause pcre_compile() to search forwards in
235        the pattern for the relevant set of parentheses. This search went wrong
236        when there were unescaped parentheses in a character class, parentheses
237        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
239    33. "Subroutine" calls and backreferences were previously restricted to
240        referencing subpatterns earlier in the regex. This restriction has now
241        been removed.
243    34. Added a number of extra features that are going to be in Perl 5.10. On the
244        whole, these are just syntactic alternatives for features that PCRE had
245        previously implemented using the Python syntax or my own invention. The
246        other formats are all retained for compatibility.
248        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
249            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
250            also .NET compatible.
252        (b) A recursion or subroutine call to a named group can now be defined as
253            (?&name) as well as (?P>name).
255        (c) A backreference to a named group can now be defined as \k<name> or
256            \k'name' as well as (?P=name). The new forms, as well as being in Perl
257            5.10, are also .NET compatible.
259        (d) A conditional reference to a named group can now use the syntax
260            (?(<name>) or (?('name') as well as (?(name).
262        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
263            groups (named and numbered) that are never evaluated inline, but can be
264            called as "subroutines" from elsewhere. In effect, the DEFINE condition
265            is always false. There may be only one alternative in such a group.
267        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
268            as the simple (?(R). The condition is true only if the most recent
269            recursion is that of the given number or name. It does not search out
270            through the entire recursion stack.
272        (g) The escape \gN or \g{N} has been added, where N is a positive or
273            negative number, specifying an absolute or relative reference.
275    35. Tidied to get rid of some further signed/unsigned compiler warnings and
276        some "unreachable code" warnings.
278    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
279        things, this adds five new scripts.
281    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
282        There were also incompatibilities regarding the handling of \Q..\E inside
283        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
284        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
286    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
287        matches an empty string, and forcibly breaks the loop. There were bugs in
288        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
289        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
290        separate and independent bugs (that affected different cases) have been
291        fixed.
293    39. Refactored the code to abolish the use of different opcodes for small
294        capturing bracket numbers. This is a tidy that I avoided doing when I
295        removed the limit on the number of capturing brackets for 3.5 back in 2001.
296        The new approach is not only tidier, it makes it possible to reduce the
297        memory needed to fix the previous bug (38).
299    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
300        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
301        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
302        mode.
304    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
305        report.
307    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
308        copy construction and assignment in the C++ wrapper.
310    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
311        couple of bugs that could have given wrong results in the "--newline=crlf"
312        case.
314    44. Added a number of casts and did some reorganization of signed/unsigned int
315        variables following suggestions from Dair Grant. Also renamed the variable
316        "this" as "item" because it is a C++ keyword.
318    45. Arranged for dftables to add
320          #include "pcre_internal.h"
322        to pcre_chartables.c because without it, gcc 4.x may remove the array
323        definition from the final binary if PCRE is built into a static library and
324        dead code stripping is activated.
326    46. For an unanchored pattern, if a match attempt fails at the start of a
327        newline sequence, and the newline setting is CRLF or ANY, and the next two
328        characters are CRLF, advance by two characters instead of one.
331    Version 6.7 04-Jul-06
332    ---------------------
334     1. In order to handle tests when input lines are enormously long, pcretest has
335        been re-factored so that it automatically extends its buffers when
336        necessary. The code is crude, but this _is_ just a test program. The
337        default size has been increased from 32K to 50K.
339     2. The code in pcre_study() was using the value of the re argument before
340        testing it for NULL. (Of course, in any sensible call of the function, it
341        won't be NULL.)
343     3. The memmove() emulation function in pcre_internal.h, which is used on
344        systems that lack both memmove() and bcopy() - that is, hardly ever -
345        was missing a "static" storage class specifier.
347     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
348        containing an extended class (one that cannot be represented by a bitmap
349        because it contains high-valued characters or Unicode property items, e.g.
350        [\pZ]). Almost always one would set UTF-8 mode when processing such a
351        pattern, but PCRE should not loop if you do not (it no longer does).
352        [Detail: two cases were found: (a) a repeated subpattern containing an
353        extended class; (b) a recursive reference to a subpattern that followed a
354        previous extended class. It wasn't skipping over the extended class
355        correctly when UTF-8 mode was not set.]
357     5. A negated single-character class was not being recognized as fixed-length
358        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
359        compile error "lookbehind assertion is not fixed length".
361     6. The RunPerlTest auxiliary script was showing an unexpected difference
362        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
363        write a Perl script that can interpret lines of an input file either as
364        byte characters or as UTF-8, which is what "perltest" was being required to
365        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
366        can't do is switch easily at run time between having the "use utf8;" pragma
367        or not. In the end, I fudged it by using the RunPerlTest script to insert
368        "use utf8;" explicitly for the UTF-8 tests.
370     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
371        the end of the subject string, contrary to the documentation and to what
372        Perl does. This was true of both matching functions. Now it matches only at
373        the start of the subject and immediately after *internal* newlines.
375     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
376        a pointer to an int instead of a pointer to an unsigned long int. This
377        caused problems on 64-bit systems.
379     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
380        instance of the 'standard' template library not being so standard".
382    10. There was no check on the number of named subpatterns nor the maximum
383        length of a subpattern name. The product of these values is used to compute
384        the size of the memory block for a compiled pattern. By supplying a very
385        long subpattern name and a large number of named subpatterns, the size
386        computation could be caused to overflow. This is now prevented by limiting
387        the length of names to 32 characters, and the number of named subpatterns
388        to 10,000.
390    11. Subpatterns that are repeated with specific counts have to be replicated in
391        the compiled pattern. The size of memory for this was computed from the
392        length of the subpattern and the repeat count. The latter is limited to
393        65535, but there was no limit on the former, meaning that integer overflow
394        could in principle occur. The compiled length of a repeated subpattern is
395        now limited to 30,000 bytes in order to prevent this.
397    12. Added the optional facility to have named substrings with the same name.
399    13. Added the ability to use a named substring as a condition, using the
400        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
401        are numbers (not recommended). Forward references are permitted.
403    14. Added forward references in named backreferences (if you see what I mean).
405    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
406        pattern could run off the end of the subject. For example, the pattern
407        "(?s)(.{1,5})"8 did this with the subject "ab".
409    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
410        PCRE_CASELESS was set when matching characters that were quantified with ?
411        or *.
413    17. A character class other than a single negated character that had a minimum
414        but no maximum quantifier - for example [ab]{6,} - was not handled
415        correctly by pce_dfa_exec(). It would match only one character.
417    18. A valid (though odd) pattern that looked like a POSIX character
418        class but used an invalid character after [ (for example [[,abc,]]) caused
419        pcre_compile() to give the error "Failed: internal error: code overflow" or
420        in some cases to crash with a glibc free() error. This could even happen if
421        the pattern terminated after [[ but there just happened to be a sequence of
422        letters, a binary zero, and a closing ] in the memory that followed.
424    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
425        over the years. Originally (before any Unicode support), just the bottom 8
426        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
427        output from "man perlunicode" includes this:
429          The regular expression compiler produces polymorphic opcodes.  That
430          is, the pattern adapts to the data and automatically switches to
431          the Unicode character scheme when presented with Unicode data--or
432          instead uses a traditional byte scheme when presented with byte
433          data.
435        Sadly, a wide octal escape does not cause a switch, and in a string with
436        no other multibyte characters, these octal escapes are treated as before.
437        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
438        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
439        Unicode string.
441        I have not perpetrated such confusion in PCRE. Up till now, it took just
442        the bottom 8 bits, as in old Perl. I have now made octal escapes with
443        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
444        translate to the appropriate multibyte character.
446    29. Applied some refactoring to reduce the number of warnings from Microsoft
447        and Borland compilers. This has included removing the fudge introduced
448        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
449        a warning about an unused variable.
451    21. PCRE has not included VT (character 0x0b) in the set of whitespace
452        characters since release 4.0, because Perl (from release 5.004) does not.
453        [Or at least, is documented not to: some releases seem to be in conflict
454        with the documentation.] However, when a pattern was studied with
455        pcre_study() and all its branches started with \s, PCRE still included VT
456        as a possible starting character. Of course, this did no harm; it just
457        caused an unnecessary match attempt.
459    22. Removed a now-redundant internal flag bit that recorded the fact that case
460        dependency changed within the pattern. This was once needed for "required
461        byte" processing, but is no longer used. This recovers a now-scarce options
462        bit. Also moved the least significant internal flag bit to the most-
463        significant bit of the word, which was not previously used (hangover from
464        the days when it was an int rather than a uint) to free up another bit for
465        the future.
467    23. Added support for CRLF line endings as well as CR and LF. As well as the
468        default being selectable at build time, it can now be changed at runtime
469        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
470        specify that it is scanning data with non-default line endings.
472    24. Changed the definition of CXXLINK to make it agree with the definition of
473        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
475    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
476        recursions. This makes a big different to stack usage for some patterns.
478    26. If a subpattern containing a named recursion or subroutine reference such
479        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
480        the space required for the compiled pattern went wrong and gave too small a
481        value. Depending on the environment, this could lead to "Failed: internal
482        error: code overflow at offset 49" or "glibc detected double free or
483        corruption" errors.
485    27. Applied patches from Google (a) to support the new newline modes and (b) to
486        advance over multibyte UTF-8 characters in GlobalReplace.
488    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
489        difference for some implementation of PCRE in some Windows version.
491    29. Added some extra testing facilities to pcretest:
493        \q<number>   in a data line sets the "match limit" value
494        \Q<number>   in a data line sets the "match recursion limt" value
495        -S <number>  sets the stack size, where <number> is in megabytes
497        The -S option isn't available for Windows.
500    Version 6.6 06-Feb-06
501    ---------------------
503     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
504        in pcreposix.h. I have copied the definition from pcre.h.
506     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
507        because pcre.h is no longer a built file.
509     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
510        not normally included in the compiled code.
513    Version 6.5 01-Feb-06
514    ---------------------
516     1. When using the partial match feature with pcre_dfa_exec(), it was not
517        anchoring the second and subsequent partial matches at the new starting
518        point. This could lead to incorrect results. For example, with the pattern
519        /1234/, partially matching against "123" and then "a4" gave a match.
521     2. Changes to pcregrep:
523        (a) All non-match returns from pcre_exec() were being treated as failures
524            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
525            error message is output. Some extra information is given for the
526            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
527            probably the only errors that are likely to be caused by users (by
528            specifying a regex that has nested indefinite repeats, for instance).
529            If there are more than 20 of these errors, pcregrep is abandoned.
531        (b) A binary zero was treated as data while matching, but terminated the
532            output line if it was written out. This has been fixed: binary zeroes
533            are now no different to any other data bytes.
535        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
536            used to set a locale for matching. The --locale=xxxx long option has
537            been added (no short equivalent) to specify a locale explicitly on the
538            pcregrep command, overriding the environment variables.
540        (d) When -B was used with -n, some line numbers in the output were one less
541            than they should have been.
543        (e) Added the -o (--only-matching) option.
545        (f) If -A or -C was used with -c (count only), some lines of context were
546            accidentally printed for the final match.
548        (g) Added the -H (--with-filename) option.
550        (h) The combination of options -rh failed to suppress file names for files
551            that were found from directory arguments.
553        (i) Added the -D (--devices) and -d (--directories) options.
555        (j) Added the -F (--fixed-strings) option.
557        (k) Allow "-" to be used as a file name for -f as well as for a data file.
559        (l) Added the --colo(u)r option.
561        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
562            is not present by default.
564     3. A nasty bug was discovered in the handling of recursive patterns, that is,
565        items such as (?R) or (?1), when the recursion could match a number of
566        alternatives. If it matched one of the alternatives, but subsequently,
567        outside the recursion, there was a failure, the code tried to back up into
568        the recursion. However, because of the way PCRE is implemented, this is not
569        possible, and the result was an incorrect result from the match.
571        In order to prevent this happening, the specification of recursion has
572        been changed so that all such subpatterns are automatically treated as
573        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
575     4. I had overlooked the fact that, in some locales, there are characters for
576        which isalpha() is true but neither isupper() nor islower() are true. In
577        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
578        and ordfeminine) are like this. This affected the treatment of \w and \W
579        when they appeared in character classes, but not when they appeared outside
580        a character class. The bit map for "word" characters is now created
581        separately from the results of isalnum() instead of just taking it from the
582        upper, lower, and digit maps. (Plus the underscore character, of course.)
584     5. The above bug also affected the handling of POSIX character classes such as
585        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
586        permanent tables. Instead, the bit maps for such a class were previously
587        created as the appropriate unions of the upper, lower, and digit bitmaps.
588        Now they are created by subtraction from the [[:word:]] class, which has
589        its own bitmap.
591     6. The [[:blank:]] character class matches horizontal, but not vertical space.
592        It is created by subtracting the vertical space characters (\x09, \x0a,
593        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
594        subtraction was done in the overall bitmap for a character class, meaning
595        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
596        be recognized. This bug has been fixed.
598     7. Patches from the folks at Google:
600          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
601          real life, but is still worth protecting against".
603          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
604          regular expressions".
606          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
607          have it.
609          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
610          "configure" and the latter not, in order to fix a problem somebody had
611          with compiling the Arg class on HP-UX.
613          (e) Improve the error-handling of the C++ wrapper a little bit.
615          (f) New tests for checking recursion limiting.
617     8. The pcre_memmove() function, which is used only if the environment does not
618        have a standard memmove() function (and is therefore rarely compiled),
619        contained two bugs: (a) use of int instead of size_t, and (b) it was not
620        returning a result (though PCRE never actually uses the result).
622     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
623        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
624        returned instead of calling malloc() with an overflowing number that would
625        most likely cause subsequent chaos.
627    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
629    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
630        with this option is matched, the nmatch and pmatch options of regexec() are
631        ignored.
633    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
634        provided in case anyone wants to the the POSIX interface with UTF-8
635        strings.
637    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
638        C++ linking (needed for some HP-UX environments).
640    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
641        (unused parameter) and in the pcre_printint() function (omitted "default"
642        switch label when the default is to do nothing).
644    15. Added some code to make it possible, when PCRE is compiled as a C++
645        library, to replace subject pointers for pcre_exec() with a smart pointer
646        class, thus making it possible to process discontinuous strings.
648    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
649        much the same function. They were added by different people who were trying
650        to make PCRE easy to compile on non-Unix systems. It has been suggested
651        that PCRE_EXPORT be abolished now that there is more automatic apparatus
652        for compiling on Windows systems. I have therefore replaced it with
653        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
654        defaults to "extern" for C or "extern C" for C++, which works fine on
655        Unix-like systems. It is now possible to override the value of PCRE_DATA_
656        SCOPE with something explicit in config.h. In addition:
658        (a) pcreposix.h still had just "extern" instead of either of these macros;
659            I have replaced it with PCRE_DATA_SCOPE.
661        (b) Functions such as _pcre_xclass(), which are internal to the library,
662            but external in the C sense, all had PCRE_EXPORT in their definitions.
663            This is apparently wrong for the Windows case, so I have removed it.
664            (It makes no difference on Unix-like systems.)
666    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
667        of recursive calls to match(). This is different to MATCH_LIMIT because
668        that limits the total number of calls to match(), not all of which increase
669        the depth of recursion. Limiting the recursion depth limits the amount of
670        stack (or heap if NO_RECURSE is set) that is used. The default can be set
671        when PCRE is compiled, and changed at run time. A patch from Google adds
672        this functionality to the C++ interface.
674    18. Changes to the handling of Unicode character properties:
676        (a) Updated the table to Unicode 4.1.0.
678        (b) Recognize characters that are not in the table as "Cn" (undefined).
680        (c) I revised the way the table is implemented to a much improved format
681            which includes recognition of ranges. It now supports the ranges that
682            are defined in UnicodeData.txt, and it also amalgamates other
683            characters into ranges. This has reduced the number of entries in the
684            table from around 16,000 to around 3,000, thus reducing its size
685            considerably. I realized I did not need to use a tree structure after
686            all - a binary chop search is just as efficient. Having reduced the
687            number of entries, I extended their size from 6 bytes to 8 bytes to
688            allow for more data.
690        (d) Added support for Unicode script names via properties such as \p{Han}.
692    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
693        matching that character.
695    20. When matching a repeated Unicode property with a minimum greater than zero,
696        (for example \pL{2,}), PCRE could look past the end of the subject if it
697        reached it while seeking the minimum number of characters. This could
698        happen only if some of the characters were more than one byte long, because
699        there is a check for at least the minimum number of bytes.
701    21. Refactored the implementation of \p and \P so as to be more general, to
702        allow for more different types of property in future. This has changed the
703        compiled form incompatibly. Anybody with saved compiled patterns that use
704        \p or \P will have to recompile them.
706    22. Added "Any" and "L&" to the supported property types.
708    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
709        but give a compile time error if the value is greater than 0xff.
711    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
712        accidentally not being installed or uninstalled.
714    25. The pcre.h file was built from pcre.h.in, but the only changes that were
715        made were to insert the current release number. This seemed silly, because
716        it made things harder for people building PCRE on systems that don't run
717        "configure". I have turned pcre.h into a distributed file, no longer built
718        by "configure", with the version identification directly included. There is
719        no longer a pcre.h.in file.
721        However, this change necessitated a change to the pcre-config script as
722        well. It is built from pcre-config.in, and one of the substitutions was the
723        release number. I have updated configure.ac so that ./configure now finds
724        the release number by grepping pcre.h.
726    26. Added the ability to run the tests under valgrind.
729    Version 6.4 05-Sep-05
730    ---------------------
732     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
733        "--" to be printed when multiple files were scanned, even when none of the
734        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
735        consider it to be a bug, and have restored the previous behaviour.
737     2. A couple of code tidies to get rid of compiler warnings.
739     3. The pcretest program used to cheat by referring to symbols in the library
740        whose names begin with _pcre_. These are internal symbols that are not
741        really supposed to be visible externally, and in some environments it is
742        possible to suppress them. The cheating is now confined to including
743        certain files from the library's source, which is a bit cleaner.
745     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
746        file's purpose clearer.
748     5. Reorganized pcre_ucp_findchar().
751    Version 6.3 15-Aug-05
752    ---------------------
754     1. The file libpcre.pc.in did not have general read permission in the tarball.
756     2. There were some problems when building without C++ support:
758        (a) If C++ support was not built, "make install" and "make test" still
759            tried to test it.
761        (b) There were problems when the value of CXX was explicitly set. Some
762            changes have been made to try to fix these, and ...
764        (c) --disable-cpp can now be used to explicitly disable C++ support.
766        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
767            backslash in a target when C++ was disabled. This confuses some
768            versions of "make", apparently. Using an intermediate variable solves
769            this. (Same for CPP_LOBJ.)
771     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
772        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
773        necessary on certain architectures.
775     4. Added a setting of -export-symbols-regex to the link command to remove
776        those symbols that are exported in the C sense, but actually are local
777        within the library, and not documented. Their names all begin with
778        "_pcre_". This is not a perfect job, because (a) we have to except some
779        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
780        available (and never for static libraries). I have made a note to try to
781        find a way round (a) in the future.
784    Version 6.2 01-Aug-05
785    ---------------------
787     1. There was no test for integer overflow of quantifier values. A construction
788        such as {1111111111111111} would give undefined results. What is worse, if
789        a minimum quantifier for a parenthesized subpattern overflowed and became
790        negative, the calculation of the memory size went wrong. This could have
791        led to memory overwriting.
793     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
795     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
796        operating environments where this matters.
798     4. Applied Giuseppe Maxia's patch to add additional features for controlling
799        PCRE options from within the C++ wrapper.
801     5. Named capturing subpatterns were not being correctly counted when a pattern
802        was compiled. This caused two problems: (a) If there were more than 100
803        such subpatterns, the calculation of the memory needed for the whole
804        compiled pattern went wrong, leading to an overflow error. (b) Numerical
805        back references of the form \12, where the number was greater than 9, were
806        not recognized as back references, even though there were sufficient
807        previous subpatterns.
809     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
810        versions of gcc, e.g. 2.95.4.
813    Version 6.1 21-Jun-05
814    ---------------------
816     1. There was one reference to the variable "posix" in pcretest.c that was not
817        surrounded by "#if !defined NOPOSIX".
819     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
820        the cross-check on the old pcre_info() function, for the benefit of the
821        cut-down version of PCRE that is currently imported into Exim.
823     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
824        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
825        patterns that start (?i) but I don't think that matters. The use of (?i) is
826        just an example; this all applies to the other options as well.
828     4. Since libtool seems to echo the compile commands it is issuing, the output
829        from "make" can be reduced a bit by putting "@" in front of each libtool
830        compile command.
832     5. Patch from the folks at Google for configure.in to be a bit more thorough
833        in checking for a suitable C++ installation before trying to compile the
834        C++ stuff. This should fix a reported problem when a compiler was present,
835        but no suitable headers.
837     6. The man pages all had just "PCRE" as their title. I have changed them to
838        be the relevant file name. I have also arranged that these names are
839        retained in the file doc/pcre.txt, which is a concatenation in text format
840        of all the man pages except the little individual ones for each function.
842     7. The NON-UNIX-USE file had not been updated for the different set of source
843        files that come with release 6. I also added a few comments about the C++
844        wrapper.
847    Version 6.0 07-Jun-05
848    ---------------------
850     1. Some minor internal re-organization to help with my DFA experiments.
852     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
853        didn't matter for the library itself when fully configured, but did matter
854        when compiling without UCP support, or within Exim, where the ucp files are
855        not imported.
857     3. Refactoring of the library code to split up the various functions into
858        different source modules. The addition of the new DFA matching code (see
859        below) to a single monolithic source would have made it really too
860        unwieldy, quite apart from causing all the code to be include in a
861        statically linked application, when only some functions are used. This is
862        relevant even without the DFA addition now that patterns can be compiled in
863        one application and matched in another.
865        The downside of splitting up is that there have to be some external
866        functions and data tables that are used internally in different modules of
867        the library but which are not part of the API. These have all had their
868        names changed to start with "_pcre_" so that they are unlikely to clash
869        with other external names.
871     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
872        a different (DFA) algorithm. Although it is slower than the original
873        function, it does have some advantages for certain types of matching
874        problem.
876     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
877        including restarting after a partial match.
879     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
880        defined when compiling for Windows was sent to me. I have put it into the
881        code, though I have no means of testing or verifying it.
883     7. Added the pcre_refcount() auxiliary function.
885     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
886        match before or at the first newline in the subject string. In pcretest,
887        the /f option on a pattern can be used to set this.
889     9. A repeated \w when used in UTF-8 mode with characters greater than 256
890        would behave wrongly. This has been present in PCRE since release 4.0.
892    10. A number of changes to the pcregrep command:
894        (a) Refactored how -x works; insert ^(...)$ instead of setting
895            PCRE_ANCHORED and checking the length, in preparation for adding
896            something similar for -w.
898        (b) Added the -w (match as a word) option.
900        (c) Refactored the way lines are read and buffered so as to have more
901            than one at a time available.
903        (d) Implemented a pcregrep test script.
905        (e) Added the -M (multiline match) option. This allows patterns to match
906            over several lines of the subject. The buffering ensures that at least
907            8K, or the rest of the document (whichever is the shorter) is available
908            for matching (and similarly the previous 8K for lookbehind assertions).
910        (f) Changed the --help output so that it now says
912              -w, --word-regex(p)
914            instead of two lines, one with "regex" and the other with "regexp"
915            because that confused at least one person since the short forms are the
916            same. (This required a bit of code, as the output is generated
917            automatically from a table. It wasn't just a text change.)
919        (g) -- can be used to terminate pcregrep options if the next thing isn't an
920            option but starts with a hyphen. Could be a pattern or a path name
921            starting with a hyphen, for instance.
923        (h) "-" can be given as a file name to represent stdin.
925        (i) When file names are being printed, "(standard input)" is used for
926            the standard input, for compatibility with GNU grep. Previously
927            "<stdin>" was used.
929        (j) The option --label=xxx can be used to supply a name to be used for
930            stdin when file names are being printed. There is no short form.
932        (k) Re-factored the options decoding logic because we are going to add
933            two more options that take data. Such options can now be given in four
934            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
936        (l) Added the -A, -B, and -C options for requesting that lines of context
937            around matches be printed.
939        (m) Added the -L option to print the names of files that do not contain
940            any matching lines, that is, the complement of -l.
942        (n) The return code is 2 if any file cannot be opened, but pcregrep does
943            continue to scan other files.
945        (o) The -s option was incorrectly implemented. For compatibility with other
946            greps, it now suppresses the error message for a non-existent or non-
947            accessible file (but not the return code). There is a new option called
948            -q that suppresses the output of matching lines, which was what -s was
949            previously doing.
951        (p) Added --include and --exclude options to specify files for inclusion
952            and exclusion when recursing.
954    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
955        Hopefully, it now does.
957    12. Missing cast in pcre_study().
959    13. Added an "uninstall" target to the makefile.
961    14. Replaced "extern" in the function prototypes in Makefile.in with
962        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
963        world, but is set differently for Windows.
965    15. Added a second compiling function called pcre_compile2(). The only
966        difference is that it has an extra argument, which is a pointer to an
967        integer error code. When there is a compile-time failure, this is set
968        non-zero, in addition to the error test pointer being set to point to an
969        error message. The new argument may be NULL if no error number is required
970        (but then you may as well call pcre_compile(), which is now just a
971        wrapper). This facility is provided because some applications need a
972        numeric error indication, but it has also enabled me to tidy up the way
973        compile-time errors are handled in the POSIX wrapper.
975    16. Added VPATH=.libs to the makefile; this should help when building with one
976        prefix path and installing with another. (Or so I'm told by someone who
977        knows more about this stuff than I do.)
979    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
980        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
981        match everything, including newlines. This is not POSIX-compatible, but
982        somebody wanted the feature. From pcretest it can be activated by using
983        both the P and the s flags.
985    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
987    19. libpcre.pc was being incorrectly installed as executable.
989    20. A couple of places in pcretest check for end-of-line by looking for '\n';
990        it now also looks for '\r' so that it will work unmodified on Windows.
992    21. Added Google's contributed C++ wrapper to the distribution.
994    22. Added some untidy missing memory free() calls in pcretest, to keep
995        Electric Fence happy when testing.
999    Version 5.0 13-Sep-04
1000    ---------------------
1002     1. Internal change: literal characters are no longer packed up into items
1003        containing multiple characters in a single byte-string. Each character
1004        is now matched using a separate opcode. However, there may be more than one
1005        byte in the character in UTF-8 mode.
1007     2. The pcre_callout_block structure has two new fields: pattern_position and
1008        next_item_length. These contain the offset in the pattern to the next match
1009        item, and its length, respectively.
1011     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1012        insertion of callouts before each pattern item. Added the /C option to
1013        pcretest to make use of this.
1015     4. On the advice of a Windows user, the lines
1017          #if defined(_WIN32) || defined(WIN32)
1018          _setmode( _fileno( stdout ), 0x8000 );
1019          #endif  /* defined(_WIN32) || defined(WIN32) */
1021        have been added to the source of pcretest. This apparently does useful
1022        magic in relation to line terminators.
1024     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1025        for the benefit of those environments where the "b" makes a difference.
1027     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1028        to know about it. I have put a hack into configure.in that adds in code
1029        to set GCC=yes if CC=icc. This seems to end up at a point in the
1030        generated configure script that is early enough to affect the setting of
1031        compiler options, which is what is needed, but I have no means of testing
1032        whether it really works. (The user who reported this had patched the
1033        generated configure script, which of course I cannot do.)
1035        LATER: After change 22 below (new libtool files), the configure script
1036        seems to know about icc (and also ecc). Therefore, I have commented out
1037        this hack in configure.in.
1039     7. Added support for pkg-config (2 patches were sent in).
1041     8. Negated POSIX character classes that used a combination of internal tables
1042        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1043        [[:^ascii]]. Typically, they would match almost any characters. The other
1044        POSIX classes were not broken in this way.
1046     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1047        to find the match, as PCRE was deluded into thinking that the match had to
1048        start at the start point or following a newline. The same bug applied to
1049        patterns with negative forward assertions or any backward assertions
1050        preceding ".*" at the start, unless the pattern required a fixed first
1051        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1053    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1054        starting at the last subject character, bytes beyond the end of the subject
1055        string were read.
1057    11. Renamed the variable "class" as "classbits" to make life easier for C++
1058        users. (Previously there was a macro definition, but it apparently wasn't
1059        enough.)
1061    12. Added the new field "tables" to the extra data so that tables can be passed
1062        in at exec time, or the internal tables can be re-selected. This allows
1063        a compiled regex to be saved and re-used at a later time by a different
1064        program that might have everything at different addresses.
1066    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1067        -R library as well as a -L library.
1069    14. The debugging options of pcretest (-d on the command line or D on a
1070        pattern) showed incorrect output for anything following an extended class
1071        that contained multibyte characters and which was followed by a quantifier.
1073    15. Added optional support for general category Unicode character properties
1074        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1075        support. It adds about 90K to the size of the library. The meanings of the
1076        inbuilt class escapes such as \d and \s have NOT been changed.
1078    16. Updated pcredemo.c to include calls to free() to release the memory for the
1079        compiled pattern.
1081    17. The generated file chartables.c was being created in the source directory
1082        instead of in the building directory. This caused the build to fail if the
1083        source directory was different from the building directory, and was
1084        read-only.
1086    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1087        file. No doubt somebody will tell me if they don't make sense... Also added
1088        Dan Mooney's comments about building on OpenVMS.
1090    19. Added support for partial matching via the PCRE_PARTIAL option for
1091        pcre_exec() and the \P data escape in pcretest.
1093    20. Extended pcretest with 3 new pattern features:
1095        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1096              write the compiled pattern to the file whose name is "rest-of-line".
1097              This is a straight binary dump of the data, with the saved pointer to
1098              the character tables forced to be NULL. The study data, if any, is
1099              written too. After writing, pcretest reads a new pattern.
1101        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1102              compiled pattern from the given file. There must not be any
1103              occurrences of "<" in the file name (pretty unlikely); if there are,
1104              pcretest will instead treat the initial "<" as a pattern delimiter.
1105              After reading in the pattern, pcretest goes on to read data lines as
1106              usual.
1108        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1109              and 16-bit fields in a compiled pattern, to simulate a pattern that
1110              was compiled on a host of opposite endianness.
1112    21. The pcre-exec() function can now cope with patterns that were compiled on
1113        hosts of opposite endianness, with this restriction:
1115          As for any compiled expression that is saved and used later, the tables
1116          pointer field cannot be preserved; the extra_data field in the arguments
1117          to pcre_exec() should be used to pass in a tables address if a value
1118          other than the default internal tables were used at compile time.
1120    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1121        now diagnosed as an error. Previously, most of the time, a negative number
1122        would have been treated as zero, but if in addition "ovector" was passed as
1123        NULL, a crash could occur.
1125    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1126        new versions from the libtool 1.5 distribution (the last one is a copy of
1127        a file called libtool.m4). This seems to have fixed the need to patch
1128        "configure" to support Darwin 1.3 (which I used to do). However, I still
1129        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1130        workstation).
1132    24. Changed the PCRE licence to be the more standard "BSD" licence.
1135    Version 4.5 01-Dec-03
1136    ---------------------
1138     1. There has been some re-arrangement of the code for the match() function so
1139        that it can be compiled in a version that does not call itself recursively.
1140        Instead, it keeps those local variables that need separate instances for
1141        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1142        needs to "recurse". Keeping track of where control must go is done by means
1143        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1144        hide most of the details from the main code, and operates only if
1145        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1146        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1147        operating.
1149        To make it easier for callers to provide specially tailored get/free
1150        functions for this usage, two new functions, pcre_stack_malloc, and
1151        pcre_stack_free, are used. They are always called in strict stacking order,
1152        and the size of block requested is always the same.
1154        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1155        PCRE has been compiled to use the stack or the heap for recursion. The
1156        -C option of pcretest uses this to show which version is compiled.
1158        A new data escape \S, is added to pcretest; it causes the amounts of store
1159        obtained and freed by both kinds of malloc/free at match time to be added
1160        to the output.
1162     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1163        what's available on my current Linux desktop machine.
1165     3. When matching a UTF-8 string, the test for a valid string at the start has
1166        been extended. If start_offset is not zero, PCRE now checks that it points
1167        to a byte that is the start of a UTF-8 character. If not, it returns
1168        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1169        this is necessary because there may be backward assertions in the pattern.
1170        When matching the same subject several times, it may save resources to use
1171        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1173     4. The code for checking the validity of UTF-8 strings has been tightened so
1174        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1175        containing "overlong sequences".
1177     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1178        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1179        should have been "&", but it just so happened that all the cases this let
1180        through by mistake were picked up later in the function.
1182     6. I had used a variable called "isblank" - this is a C99 function, causing
1183        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1185     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1186        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1187        so the version is shown; (c) stop "make test" echoing "./RunTest".
1189     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1191     9. The prototype for memmove() for systems that don't have it was using
1192        size_t, but the inclusion of the header that defines size_t was later. I've
1193        moved the #includes for the C headers earlier to avoid this.
1195    10. Added some adjustments to the code to make it easier to compiler on certain
1196        special systems:
1198          (a) Some "const" qualifiers were missing.
1199          (b) Added the macro EXPORT before all exported functions; by default this
1200              is defined to be empty.
1201          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1202              that it reads its output file name as an argument instead of writing
1203              to the standard output and assuming this can be redirected.
1205    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1206        class containing characters with values greater than 255, PCRE compilation
1207        went into a loop.
1209    12. A recursive reference to a subpattern that was within another subpattern
1210        that had a minimum quantifier of zero caused PCRE to crash. For example,
1211        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1212        recursion. If the recursively-called subpattern itself had a zero repeat,
1213        that was OK.
1215    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1216        buffer into which it was copied (for escape processing) was still set at
1217        1024, so long lines caused crashes.
1219    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1220        "internal error: code overflow...". This applied to any character class
1221        that was followed by a possessive quantifier.
1223    15. Modified the Makefile to add libpcre.la as a prerequisite for
1224        libpcreposix.la because I was told this is needed for a parallel build to
1225        work.
1227    16. If a pattern that contained .* following optional items at the start was
1228        studied, the wrong optimizing data was generated, leading to matching
1229        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1230        matching string must start with a or b or c. The correct conclusion for
1231        this pattern is that a match can start with any character.
1234    Version 4.4 13-Aug-03
1235    ---------------------
1237     1. In UTF-8 mode, a character class containing characters with values between
1238        127 and 255 was not handled correctly if the compiled pattern was studied.
1239        In fixing this, I have also improved the studying algorithm for such
1240        classes (slightly).
1242     2. Three internal functions had redundant arguments passed to them. Removal
1243        might give a very teeny performance improvement.
1245     3. Documentation bug: the value of the capture_top field in a callout is *one
1246        more than* the number of the hightest numbered captured substring.
1248     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1249        in incorrectly linking with a previously installed version. They now link
1250        explicitly with libpcre.la.
1252     5. configure.in no longer needs to recognize Cygwin specially.
1254     6. A problem in pcre.in for Windows platforms is fixed.
1256     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1257        pcretest, it used to include the size of the study block as part of its
1258        output. Unfortunately, the structure contains a field that has a different
1259        size on different hardware architectures. This meant that the tests that
1260        showed this size failed. As the block is currently always of a fixed size,
1261        this information isn't actually particularly useful in pcretest output, so
1262        I have just removed it.
1264     8. Three pre-processor statements accidentally did not start in column 1.
1265        Sadly, there are *still* compilers around that complain, even though
1266        standard C has not required this for well over a decade. Sigh.
1268     9. In pcretest, the code for checking callouts passed small integers in the
1269        callout_data field, which is a void * field. However, some picky compilers
1270        complained about the casts involved for this on 64-bit systems. Now
1271        pcretest passes the address of the small integer instead, which should get
1272        rid of the warnings.
1274    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1275        both compile and run time, and gives an error if an invalid UTF-8 sequence
1276        is found. There is a option for disabling this check in cases where the
1277        string is known to be correct and/or the maximum performance is wanted.
1279    11. In response to a bug report, I changed one line in Makefile.in from
1281            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1282        to
1283            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1285        to look similar to other lines, but I have no way of telling whether this
1286        is the right thing to do, as I do not use Windows. No doubt I'll get told
1287        if it's wrong...
1290    Version 4.3 21-May-03
1291    ---------------------
1293    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1294       Makefile.
1296    2. Some refactoring to improve the quality of the code:
1298       (i)   The utf8_table... variables are now declared "const".
1300       (ii)  The code for \cx, which used the "case flipping" table to upper case
1301             lower case letters, now just substracts 32. This is ASCII-specific,
1302             but the whole concept of \cx is ASCII-specific, so it seems
1303             reasonable.
1305       (iii) PCRE was using its character types table to recognize decimal and
1306             hexadecimal digits in the pattern. This is silly, because it handles
1307             only 0-9, a-f, and A-F, but the character types table is locale-
1308             specific, which means strange things might happen. A private
1309             table is now used for this - though it costs 256 bytes, a table is
1310             much faster than multiple explicit tests. Of course, the standard
1311             character types table is still used for matching digits in subject
1312             strings against \d.
1314       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1315             ending in _t are). So I've renamed it as ESC_tee.
1317    3. The first argument for regexec() in the POSIX wrapper should have been
1318       defined as "const".
1320    4. Changed pcretest to use malloc() for its buffers so that they can be
1321       Electric Fenced for debugging.
1323    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1324       to read one or more bytes before the start of the subject string. Often this
1325       had no effect on PCRE's behaviour, but in some circumstances it could
1326       provoke a segmentation fault.
1328    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1329       to try to read one or more bytes before the start of the subject string.
1331    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1332       UTF-8 support could misbehave in various ways if the subject string
1333       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1334       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1335       back over UTF-8 characters.)
1338    Version 4.2 14-Apr-03
1339    ---------------------
1341    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1343    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1344         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1345         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1346         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1347         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1348           and BUILD_EXEEXT
1349         Note: automatic setting of the BUILD variables is not yet working
1350         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1351           compile-time but not at link-time
1352         [LINK]: use for linking executables only
1353         make different versions for Windows and non-Windows
1354         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1355           libraries
1356         [LINK_FOR_BUILD]: new variable
1357         [OBJEXT]: use throughout
1358         [EXEEXT]: use throughout
1359         <winshared>: new target
1360         <wininstall>: new target
1361         <dftables.o>: use native compiler
1362         <dftables>: use native linker
1363         <install>: handle Windows platform correctly
1364         <clean>: ditto
1365         <check>: ditto
1366         copy DLL to top builddir before testing
1368       As part of these changes, -no-undefined was removed again. This was reported
1369       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1370       in any case.
1372    3. Some tidies to get rid of compiler warnings:
1374       . In the match_data structure, match_limit was an unsigned long int, whereas
1375         match_call_count was an int. I've made them both unsigned long ints.
1377       . In pcretest the fact that a const uschar * doesn't automatically cast to
1378         a void * provoked a warning.
1380       . Turning on some more compiler warnings threw up some "shadow" variables
1381         and a few more missing casts.
1383    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1384       option, a class that contained a single character with a value between 128
1385       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1387    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1388       option, a class that contained several characters, but with at least one
1389       whose value was between 128 and 255 caused PCRE to crash.
1392    Version 4.1 12-Mar-03
1393    ---------------------
1395    1. Compiling with gcc -pedantic found a couple of places where casts were
1396    needed, and a string in dftables.c that was longer than standard compilers are
1397    required to support.
1399    2. Compiling with Sun's compiler found a few more places where the code could
1400    be tidied up in order to avoid warnings.
1402    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1403    first of these names is deprecated in the latest Autoconf in favour of the name
1404    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1405    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1406    analogy I have changed it to CFLAGS_FOR_BUILD.
1408    4. Added -no-undefined to the linking command in the Makefile, because this is
1409    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1410    linking step for the pcreposix library.
1412    5. PCRE was failing to diagnose the case of two named groups with the same
1413    name.
1415    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1416    literal character that is needed in the subject for a match, and scans along to
1417    ensure that it is present before embarking on the full matching process. This
1418    saves time in cases of nested unlimited repeats that are never going to match.
1419    Problem: the scan can take a lot of time if the subject is very long (e.g.
1420    megabytes), thus penalizing straightforward matches. It is now done only if the
1421    amount of subject to be scanned is less than 1000 bytes.
1423    7. A lesser problem with the same optimization is that it was recording the
1424    first character of an anchored pattern as "needed", thus provoking a search
1425    right along the subject, even when the first match of the pattern was going to
1426    fail. The "needed" character is now not set for anchored patterns, unless it
1427    follows something in the pattern that is of non-fixed length. Thus, it still
1428    fulfils its original purpose of finding quick non-matches in cases of nested
1429    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1432    Version 4.0 17-Feb-03
1433    ---------------------
1435    1. If a comment in an extended regex that started immediately after a meta-item
1436    extended to the end of string, PCRE compiled incorrect data. This could lead to
1437    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1439    2. Moved to autoconf 2.53 and libtool 1.4.2.
1441    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1442    the special perltest8 script is no longer needed - all the tests can be run
1443    from a single perltest script.
1445    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1446    by \s. It has now been removed in PCRE. This means it isn't recognized as
1447    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1448    class [:space:] *does* include VT, thereby creating a mess.
1450    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1451    space and tab.
1453    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1454    its new features into the main test script, reducing the number of scripts.
1456    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1457    were backward compatible, and made the (?i) apply to the whole pattern, as if
1458    /i were given. Now it behaves more logically, and applies the option setting
1459    only to what follows. PCRE has been changed to follow suit. However, if it
1460    finds options settings right at the start of the pattern, it extracts them into
1461    the global options, as before. Thus, they show up in the info data.
1463    8. Added support for the \Q...\E escape sequence. Characters in between are
1464    treated as literals. This is slightly different from Perl in that $ and @ are
1465    also handled as literals inside the quotes. In Perl, they will cause variable
1466    interpolation. Note the following examples:
1468        Pattern            PCRE matches      Perl matches
1470        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1471        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1472        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1474    For compatibility with Perl, \Q...\E sequences are recognized inside character
1475    classes as well as outside them.
1477    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1478    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1479    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1480    signed/unsigned warnings.
1482    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1483    option for pcretest, so I've replaced it by a simple function that does just
1484    that job.
1486    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1487    "pcregrep -".
1489    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1490    Java package. This provides some syntactic sugar for simple cases of what my
1491    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1492    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1493    item, you can use this simplified notation. Note that only makes sense with
1494    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1495    greediness, whatever the setting of the PCRE_UNGREEDY option.
1497    13. A change of greediness default within a pattern was not taking effect at
1498    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1499    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1500    was abstracted outside.
1502    14. PCRE now supports the \G assertion. It is true when the current matching
1503    position is at the start point of the match. This differs from \A when the
1504    starting offset is non-zero. Used with the /g option of pcretest (or similar
1505    code), it works in the same way as it does for Perl's /g option. If all
1506    alternatives of a regex begin with \G, the expression is anchored to the start
1507    match position, and the "anchored" flag is set in the compiled expression.
1509    15. Some bugs concerning the handling of certain option changes within patterns
1510    have been fixed. These applied to options other than (?ims). For example,
1511    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1512    been the other way round. Some of this was related to change 7 above.
1514    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1515    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1516    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1517    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1519    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1520    mode. Unlike ".", it always matches newline, whatever the setting of
1521    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1522    assertions. Perl allows it, but it doesn't (in general) work because it can't
1523    calculate the length of the lookbehind. At least, that's the case for Perl
1524    5.8.0 - I've been told they are going to document that it doesn't work in
1525    future.
1527    18. Added an error diagnosis for escapes that PCRE does not support: these are
1528    \L, \l, \N, \P, \p, \U, \u, and \X.
1530    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1531    reading past the end of the pattern in cases such as /[abcd/.
1533    20. PCRE was getting more memory than necessary for patterns with classes that
1534    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1536    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1537    compiling PCRE for use with Virtual Pascal.
1539    22. Small fix to the Makefile to make it work properly if the build is done
1540    outside the source tree.
1542    23. Added a new extension: a condition to go with recursion. If a conditional
1543    subpattern starts with (?(R) the "true" branch is used if recursion has
1544    happened, whereas the "false" branch is used only at the top level.
1546    24. When there was a very long string of literal characters (over 255 bytes
1547    without UTF support, over 250 bytes with UTF support), the computation of how
1548    much memory was required could be incorrect, leading to segfaults or other
1549    strange effects.
1551    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1552    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1553    there was a subsequent back reference to those brackets. This meant that, for
1554    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1555    possible to check for precisely this case. All we can do is abandon the
1556    optimization if .* occurs inside capturing brackets when there are any back
1557    references whatsoever. (See below for a better fix that came later.)
1559    26. The handling of the optimization for finding the first character of a
1560    non-anchored pattern, and for finding a character that is required later in the
1561    match were failing in some cases. This didn't break the matching; it just
1562    failed to optimize when it could. The way this is done has been re-implemented.
1564    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1566    28. Added a new feature that provides some of the functionality that Perl
1567    provides with (?{...}). The facility is termed a "callout". The way it is done
1568    in PCRE is for the caller to provide an optional function, by setting
1569    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1570    global variable. By default it is unset, which disables all calling out. To get
1571    the function called, the regex must include (?C) at appropriate points. This
1572    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1573    This provides a means of identifying different callout points. When PCRE
1574    reaches such a point in the regex, if pcre_callout has been set, the external
1575    function is called. It is provided with data in a structure called
1576    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1577    matching continues; if it returns a non-zero value, the match at the current
1578    point fails. However, backtracking will occur if possible. [This was changed
1579    later and other features added - see item 49 below.]
1581    29. pcretest is upgraded to test the callout functionality. It provides a
1582    callout function that displays information. By default, it shows the start of
1583    the match and the current position in the text. There are some new data escapes
1584    to vary what happens:
1586        \C+         in addition, show current contents of captured substrings
1587        \C-         do not supply a callout function
1588        \C!n        return 1 when callout number n is reached
1589        \C!n!m      return 1 when callout number n is reached for the mth time
1591    30. If pcregrep was called with the -l option and just a single file name, it
1592    output "<stdin>" if a match was found, instead of the file name.
1594    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1595    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1596    pcre_exec(). This saves a malloc/free per call. The default value of
1597    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1598    when configuring.
1600    32. The default maximum size of a compiled pattern is 64K. There have been a
1601    few cases of people hitting this limit. The code now uses macros to handle the
1602    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1603    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1604    configuring. Tests 2 and 5 work only with 2-byte links because they output
1605    debugging information about compiled patterns.
1607    33. Internal code re-arrangements:
1609    (a) Moved the debugging function for printing out a compiled regex into
1610        its own source file (printint.c) and used #include to pull it into
1611        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1612        separate copies.
1614    (b) Defined the list of op-code names for debugging as a macro in
1615        internal.h so that it is next to the definition of the opcodes.
1617    (c) Defined a table of op-code lengths for simpler skipping along compiled
1618        code. This is again a macro in internal.h so that it is next to the
1619        definition of the opcodes.
1621    34. Added support for recursive calls to individual subpatterns, along the
1622    lines of Robin Houston's patch (but implemented somewhat differently).
1624    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1625    allow it to read and process whole directories in Win32. This code was
1626    contributed by Lionel Fourquaux; it has not been tested by me.
1628    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1629    used to name a group. Names consist of alphanumerics and underscores, and must
1630    be unique. Back references use the syntax (?P=name) and recursive calls use
1631    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1632    numbers. The function pcre_fullinfo() can be used after compilation to extract
1633    a name/number map. There are three relevant calls:
1635      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1636      PCRE_INFO_NAMECOUNT            yields the number of entries
1637      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1639    The map is a vector of fixed-size entries. The size of each entry depends on
1640    the length of the longest name used. The first two bytes of each entry are the
1641    group number, most significant byte first. There follows the corresponding
1642    name, zero terminated. The names are in alphabetical order.
1644    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1645    case instead of 255. Making it the same both with and without UTF-8 support
1646    means that the same test output works with both.
1648    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1649    calling malloc() with a zero argument.
1651    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1652    optimization. I've improved things by keeping a bitmap of backreferences with
1653    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1654    fact referenced, the optimization can be applied. It is unlikely that a
1655    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1656    the match to follow \n) will appear inside brackets with a number greater than
1657    31, but if it does, any back reference > 31 suppresses the optimization.
1659    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1660    of disabling numbered capturing parentheses. Any opening parenthesis that is
1661    not followed by ? behaves as if it were followed by ?: but named parentheses
1662    can still be used for capturing (and they will acquire numbers in the usual
1663    way).
1665    41. Redesigned the return codes from the match() function into yes/no/error so
1666    that errors can be passed back from deep inside the nested calls. A malloc
1667    failure while inside a recursive subpattern call now causes the
1668    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1670    42. It is now possible to set a limit on the number of times the match()
1671    function is called in a call to pcre_exec(). This facility makes it possible to
1672    limit the amount of recursion and backtracking, though not in a directly
1673    obvious way, because the match() function is used in a number of different
1674    circumstances. The count starts from zero for each position in the subject
1675    string (for non-anchored patterns). The default limit is, for compatibility, a
1676    large number, namely 10 000 000. You can change this in two ways:
1678    (a) When configuring PCRE before making, you can use --with-match-limit=n
1679        to set a default value for the compiled library.
1681    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1682        a different value is set. See 45 below.
1684    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1686    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1687    of things that can be changed at compile time. The first argument specifies
1688    what is wanted and the second points to where the information is to be placed.
1689    The current list of available information is:
1691      PCRE_CONFIG_UTF8
1693    The output is an integer that is set to one if UTF-8 support is available;
1694    otherwise it is set to zero.
1698    The output is an integer that it set to the value of the code that is used for
1699    newline. It is either LF (10) or CR (13).
1703    The output is an integer that contains the number of bytes used for internal
1704    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1708    The output is an integer that contains the threshold above which the POSIX
1709    interface uses malloc() for output vectors. See item 31 above.
1713    The output is an unsigned integer that contains the default limit of the number
1714    of match() calls in a pcre_exec() execution. See 42 above.
1716    44. pcretest has been upgraded by the addition of the -C option. This causes it
1717    to extract all the available output from the new pcre_config() function, and to
1718    output it. The program then exits immediately.
1720    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1721    order to support additional features. One way would have been to define
1722    pcre_exec2() (for example) with extra arguments, but this would not have been
1723    extensible, and would also have required all calls to the original function to
1724    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1725    is used for passing in "extra" data from pcre_study().
1727    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1728    contains the following fields:
1730      flags         a bitmap indicating which of the following fields are set
1731      study_data    opaque data from pcre_study()
1732      match_limit   a way of specifying a limit on match() calls for a specific
1733                      call to pcre_exec()
1734      callout_data  data for callouts (see 49 below)
1736    The flag bits are also defined in pcre.h, and are
1742    The pcre_study() function now returns one of these new pcre_extra blocks, with
1743    the actual study data pointed to by the study_data field, and the
1744    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1745    before. That is, this change is entirely upwards-compatible and requires no
1746    change to existing code.
1748    If you want to pass in additional data to pcre_exec(), you can either place it
1749    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1750    block.
1752    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1753    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1754    times with different match limits, until it finds the minimum value needed for
1755    pcre_exec() to complete. The value is then output. This can be instructive; for
1756    most simple matches the number is quite small, but for pathological cases it
1757    gets very large very quickly.
1759    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1760    returns the size of the data block pointed to by the study_data field in a
1761    pcre_extra block, that is, the value that was passed as the argument to
1762    pcre_malloc() when PCRE was getting memory in which to place the information
1763    created by pcre_study(). The fourth argument should point to a size_t variable.
1764    pcretest has been extended so that this information is shown after a successful
1765    pcre_study() call when information about the compiled regex is being displayed.
1767    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1768    because what follows is always an absolute path. (Later: it turns out that this
1769    is more than cosmetic for MinGW, because it doesn't like empty path
1770    components.)
1772    49. Some changes have been made to the callout feature (see 28 above):
1774    (i)  A callout function now has three choices for what it returns:
1776           0  =>  success, carry on matching
1777         > 0  =>  failure at this point, but backtrack if possible
1778         < 0  =>  serious error, return this value from pcre_exec()
1780         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1781         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1782         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1783         use by callout functions. It will never be used by PCRE itself.
1785    (ii) The pcre_extra structure (see 45 above) has a void * field called
1786         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1787         pcre_callout_block structure has a field of the same name. The contents of
1788         the field passed in the pcre_extra structure are passed to the callout
1789         function in the corresponding field in the callout block. This makes it
1790         easier to use the same callout-containing regex from multiple threads. For
1791         testing, the pcretest program has a new data escape
1793           \C*n        pass the number n (may be negative) as callout_data
1795         If the callout function in pcretest receives a non-zero value as
1796         callout_data, it returns that value.
1798    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1799    there were some redundant $(CFLAGS) in commands that are now specified as
1800    $(LINK), which already includes $(CFLAGS).
1802    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1803    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1804    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1805    one-byte characters throughout. Note that case-insensitive matching applies
1806    only to characters whose values are less than 256. PCRE doesn't support the
1807    notion of cases for higher-valued characters.
1809    (i)   A character class whose characters are all within 0-255 is handled as
1810          a bit map, and the map is inverted for negative classes. Previously, a
1811          character > 255 always failed to match such a class; however it should
1812          match if the class was a negative one (e.g. [^ab]). This has been fixed.
1814    (ii)  A negated character class with a single character < 255 is coded as
1815          "not this character" (OP_NOT). This wasn't working properly when the test
1816          character was multibyte, either singly or repeated.
1818    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1819          mode, for example: \x{100}{2,3}.
1821    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1822          singly or repeated) now correctly test multibyte characters. However,
1823          PCRE doesn't recognize any characters with values greater than 255 as
1824          digits, spaces, or word characters. Such characters always match \D, \S,
1825          and \W, and never match \d, \s, or \w.
1827    (v)   Classes may now contain characters and character ranges with values
1828          greater than 255. For example: [ab\x{100}-\x{400}].
1830    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
1831          PCRE in UTF-8 mode.
1833    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1834    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1835    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1836    value.)
1838    53. The single man page has become too large. I have therefore split it up into
1839    a number of separate man pages. These also give rise to individual HTML pages;
1840    these are now put in a separate directory, and there is an index.html page that
1841    lists them all. Some hyperlinking between the pages has been installed.
1843    54. Added convenience functions for handling named capturing parentheses.
1845    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1846    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1847    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1848    are faulted.
1850    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1851    calling configure. These values are used when compiling the dftables.c program
1852    which is run to generate the source of the default character tables. They
1853    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1854    you will need to set these values.
1856    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1859    Version 3.9 02-Jan-02
1860    ---------------------
1862    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1864    2. If --disable-static was given, the building process failed when trying to
1865    build pcretest and pcregrep. (For some reason it was using libtool to compile
1866    them, which is not right, as they aren't part of the library.)
1869    Version 3.8 18-Dec-01
1870    ---------------------
1872    1. The experimental UTF-8 code was completely screwed up. It was packing the
1873    bytes in the wrong order. How dumb can you get?
1876    Version 3.7 29-Oct-01
1877    ---------------------
1879    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
1880    This caused pcretest, when used on the test data, to segfault. Unfortunately,
1881    this didn't happen under Solaris 8, where I normally test things.
1883    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
1884    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
1885    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
1886    this fix an hour or so after the initial 3.7 release.)
1889    Version 3.6 23-Oct-01
1890    ---------------------
1892    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
1893    offsets passed as NULL with zero offset count.
1895    2. The config.guess and config.sub files had not been updated when I moved to
1896    the latest autoconf.
1899    Version 3.5 15-Aug-01
1900    ---------------------
1902    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
1903    had been forgotten.
1905    2. By using declared but undefined structures, we can avoid using "void"
1906    definitions in pcre.h while keeping the internal definitions of the structures
1907    private.
1909    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
1910    user point of view, this means that both static and shared libraries are built
1911    by default, but this can be individually controlled. More of the work of
1912    handling this static/shared cases is now inside libtool instead of PCRE's make
1913    file.
1915    4. The pcretest utility is now installed along with pcregrep because it is
1916    useful for users (to test regexs) and by doing this, it automatically gets
1917    relinked by libtool. The documentation has been turned into a man page, so
1918    there are now .1, .txt, and .html versions in /doc.
1920    5. Upgrades to pcregrep:
1921       (i)   Added long-form option names like gnu grep.
1922       (ii)  Added --help to list all options with an explanatory phrase.
1923       (iii) Added -r, --recursive to recurse into sub-directories.
1924       (iv)  Added -f, --file to read patterns from a file.
1926    6. pcre_exec() was referring to its "code" argument before testing that
1927    argument for NULL (and giving an error if it was NULL).
1929    7. Upgraded Makefile.in to allow for compiling in a different directory from
1930    the source directory.
1932    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
1933    options bits, the pointer it was passed was to an int instead of to an unsigned
1934    long int. This mattered only on 64-bit systems.
1936    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
1937    generated) instead of pcre.in, which it its source. Also made the same change
1938    in several of the .c files.
1940    10. A new release of gcc defines printf() as a macro, which broke pcretest
1941    because it had an ifdef in the middle of a string argument for printf(). Fixed
1942    by using separate calls to printf().
1944    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
1945    script, to force use of CR or LF instead of \n in the source. On non-Unix
1946    systems, the value can be set in config.h.
1948    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
1949    absolute limit. Changed the text of the error message to make this clear, and
1950    likewise updated the man page.
1952    13. The limit of 99 on the number of capturing subpatterns has been removed.
1953    The new limit is 65535, which I hope will not be a "real" limit.
1956  Version 3.4 22-Aug-00  Version 3.4 22-Aug-00
1957  ---------------------  ---------------------

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