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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.2 01-May-07
5    ---------------------
7     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
8        which is apparently normally available under Windows.
10     2. Re-jig the pcregrep tests with different newline settings in an attempt
11        to make them independent of the local environment's newline setting.
13     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
15     4. Some of the "internals" tests were previously cut out when the link size
16        was not 2, because the output contained actual offsets. The recent new
17        "Z" feature of pcretest means that these can be cut out, making the tests
18        usable with all link sizes.
20     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
21        stack recursion. This gives a massive performance boost under BSD, but just
22        a small improvement under Linux. However, it saves one field in the frame
23        in all cases.
25     6. Added more features from the forthcoming Perl 5.10:
27        (a) (?-n) (where n is a string of digits) is a relative subroutine or
28            recursion call. It refers to the nth most recently opened parentheses.
30        (b) (?+n) is also a relative subroutine call; it refers to the nth next
31            to be opened parentheses.
33        (c) Conditions that refer to capturing parentheses can be specified
34            relatively, for example, (?(-2)... or (?(+3)...
36        (d) \K resets the start of the current match so that everything before
37            is not part of it.
40    Version 7.1 24-Apr-07
41    ---------------------
43     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
44        that is more "standard", making use of automake and other Autotools. There
45        is some re-arrangement of the files and adjustment of comments consequent
46        on this.
48     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
49        for recursive directory scanning broke on some systems because the files
50        are not scanned in any specific order and on different systems the order
51        was different. A call to "sort" has been inserted into RunGrepTest for the
52        approprate test as a short-term fix. In the longer term there may be an
53        alternative.
55     3. I had an email from Eric Raymond about problems translating some of PCRE's
56        man pages to HTML (despite the fact that I distribute HTML pages, some
57        people do their own conversions for various reasons). The problems
58        concerned the use of low-level troff macros .br and .in. I have therefore
59        removed all such uses from the man pages (some were redundant, some could
60        be replaced by .nf/.fi pairs). The 132html script that I use to generate
61        HTML has been updated to handle .nf/.fi and to complain if it encounters
62        .br or .in.
64     4. Updated comments in configure.ac that get placed in config.h.in and also
65        arranged for config.h to be included in the distribution, with the name
66        config.h.generic, for the benefit of those who have to compile without
67        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
69     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
70        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
71        makevp.bat for the current PCRE, using the additional files
72        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
74     6. A Windows user reported a minor discrepancy with test 2, which turned out
75        to be caused by a trailing space on an input line that had got lost in his
76        copy. The trailing space was an accident, so I've just removed it.
78     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
79        that is needed.
81     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
82        as "const" (a) because they are and (b) because it helps the PHP
83        maintainers who have recently made a script to detect big data structures
84        in the php code that should be moved to the .rodata section. I remembered
85        to update Builducptable as well, so it won't revert if ucptable.h is ever
86        re-created.
88     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
89        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
90        order to be able to cut out the UTF-8 tables in the latter when UTF-8
91        support is not required. This saves 1.5-2K of code, which is important in
92        some applications.
94        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
95        so as not to refer to the tables, even though these functions will never be
96        called when UTF-8 support is disabled. Otherwise there are problems with a
97        shared library.
99    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
101        (a) It was defining its arguments as char * instead of void *.
103        (b) It was assuming that all moves were upwards in memory; this was true
104            a long time ago when I wrote it, but is no longer the case.
106        The emulated memove() is provided for those environments that have neither
107        memmove() nor bcopy(). I didn't think anyone used it these days, but that
108        is clearly not the case, as these two bugs were recently reported.
110    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
111        and Detrail to create the HTML documentation, the .txt form of the man
112        pages, and it removes trailing spaces from listed files. It also creates
113        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
114        case, it wraps all the #defines with #ifndefs. This script should be run
115        before "make dist".
117    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
118        with Unicode property support.
120        (a) For a maximizing quantifier, if the two different cases of the
121            character were of different lengths in their UTF-8 codings (there are
122            some cases like this - I found 11), and the matching function had to
123            back up over a mixture of the two cases, it incorrectly assumed they
124            were both the same length.
126        (b) When PCRE was configured to use the heap rather than the stack for
127            recursion during matching, it was not correctly preserving the data for
128            the other case of a UTF-8 character when checking ahead for a match
129            while processing a minimizing repeat. If the check also involved
130            matching a wide character, but failed, corruption could cause an
131            erroneous result when trying to check for a repeat of the original
132            character.
134    13. Some tidying changes to the testing mechanism:
136        (a) The RunTest script now detects the internal link size and whether there
137            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
138            values substituted by "configure". (The RunGrepTest script already did
139            this for UTF-8.) The configure.ac script no longer substitutes the
140            relevant variables.
142        (b) The debugging options /B and /D in pcretest show the compiled bytecode
143            with length and offset values. This means that the output is different
144            for different internal link sizes. Test 2 is skipped for link sizes
145            other than 2 because of this, bypassing the problem. Unfortunately,
146            there was also a test in test 3 (the locale tests) that used /B and
147            failed for link sizes other than 2. Rather than cut the whole test out,
148            I have added a new /Z option to pcretest that replaces the length and
149            offset values with spaces. This is now used to make test 3 independent
150            of link size. (Test 2 will be tidied up later.)
152    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
153        segmentation fault instead of returning the appropriate error message.
155    15. In multiline mode when the newline sequence was set to "any", the pattern
156        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
157        This doesn't seem right; it now treats the CRLF combination as the line
158        ending, and so does not match in that case. It's only a pattern such as ^$
159        that would hit this one: something like ^ABC$ would have failed after \r
160        and then tried again after \r\n.
162    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
163        in an attempt to make files that differ only in their line terminators
164        compare equal. This works on Linux.
166    17. Under certain error circumstances pcregrep might try to free random memory
167        as it exited. This is now fixed, thanks to valgrind.
169    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
170        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
171        was because its rules for how to advance for /g after matching an empty
172        string at the end of a line did not allow for this case. They now check for
173        it specially.
175    20. pcretest is supposed to handle patterns and data of any length, by
176        extending its buffers when necessary. It was getting this wrong when the
177        buffer for a data line had to be extended.
179    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
180        CRLF as a newline sequence.
182    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
183        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
184        I have nevertheless tidied it up.
186    23. Added some casts to kill warnings from HP-UX ia64 compiler.
188    24. Added a man page for pcre-config.
191    Version 7.0 19-Dec-06
192    ---------------------
194     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
195        moving to gcc 4.1.1.
197     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
198        sys/time.h, which is documented as needed for this function. It doesn't
199        seem to matter on Linux, but it showed up on some releases of OS X.
201     3. It seems that there are systems where bytes whose values are greater than
202        127 match isprint() in the "C" locale. The "C" locale should be the
203        default when a C program starts up. In most systems, only ASCII printing
204        characters match isprint(). This difference caused the output from pcretest
205        to vary, making some of the tests fail. I have changed pcretest so that:
207        (a) When it is outputting text in the compiled version of a pattern, bytes
208            other than 32-126 are always shown as hex escapes.
210        (b) When it is outputting text that is a matched part of a subject string,
211            it does the same, unless a different locale has been set for the match
212            (using the /L modifier). In this case, it uses isprint() to decide.
214     4. Fixed a major bug that caused incorrect computation of the amount of memory
215        required for a compiled pattern when options that changed within the
216        pattern affected the logic of the preliminary scan that determines the
217        length. The relevant options are -x, and -i in UTF-8 mode. The result was
218        that the computed length was too small. The symptoms of this bug were
219        either the PCRE error "internal error: code overflow" from pcre_compile(),
220        or a glibc crash with a message such as "pcretest: free(): invalid next
221        size (fast)". Examples of patterns that provoked this bug (shown in
222        pcretest format) are:
224          /(?-x: )/x
225          /(?x)(?-x: \s*#\s*)/
226          /((?i)[\x{c0}])/8
227          /(?i:[\x{c0}])/8
229        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
230        is now done differently.
232     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
233        wrapper classes; (b) implement a new function in the C++ scanner that is
234        more efficient than the old way of doing things because it avoids levels of
235        recursion in the regex matching; (c) add a paragraph to the documentation
236        for the FullMatch() function.
238     6. The escape sequence \n was being treated as whatever was defined as
239        "newline". Not only was this contrary to the documentation, which states
240        that \n is character 10 (hex 0A), but it also went horribly wrong when
241        "newline" was defined as CRLF. This has been fixed.
243     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
244        was being set to -1 for the "end of line" case (supposedly a value that no
245        character can have). Though this value is never used (the check for end of
246        line is "zero bytes in current character"), it caused compiler complaints.
247        I've changed it to 0xffffffff.
249     8. In pcre_version.c, the version string was being built by a sequence of
250        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
251        string (as it is for production releases) called a macro with an empty
252        argument. The C standard says the result of this is undefined. The gcc
253        compiler treats it as an empty string (which was what was wanted) but it is
254        reported that Visual C gives an error. The source has been hacked around to
255        avoid this problem.
257     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
258        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
259        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
260        of them did).
262    10. Originally, pcretest opened its input and output without "b"; then I was
263        told that "b" was needed in some environments, so it was added for release
264        5.0 to both the input and output. (It makes no difference on Unix-like
265        systems.) Later I was told that it is wrong for the input on Windows. I've
266        now abstracted the modes into two macros, to make it easier to fiddle with
267        them, and removed "b" from the input mode under Windows.
269    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
271    12. Added -help and --help to pcretest as an official way of being reminded
272        of the options.
274    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
275        and pcrecpp.cc because they annoy compilers at high warning levels.
277    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
279    15. Fixed an occurrence of == in configure.ac that should have been = (shell
280        scripts are not C programs :-) and which was not noticed because it works
281        on Linux.
283    16. pcretest is supposed to handle any length of pattern and data line (as one
284        line or as a continued sequence of lines) by extending its input buffer if
285        necessary. This feature was broken for very long pattern lines, leading to
286        a string of junk being passed to pcre_compile() if the pattern was longer
287        than about 50K.
289    17. I have done a major re-factoring of the way pcre_compile() computes the
290        amount of memory needed for a compiled pattern. Previously, there was code
291        that made a preliminary scan of the pattern in order to do this. That was
292        OK when PCRE was new, but as the facilities have expanded, it has become
293        harder and harder to keep it in step with the real compile phase, and there
294        have been a number of bugs (see for example, 4 above). I have now found a
295        cunning way of running the real compile function in a "fake" mode that
296        enables it to compute how much memory it would need, while actually only
297        ever using a few hundred bytes of working memory and without too many
298        tests of the mode. This should make future maintenance and development
299        easier. A side effect of this work is that the limit of 200 on the nesting
300        depth of parentheses has been removed (though this was never a serious
301        limitation, I suspect). However, there is a downside: pcre_compile() now
302        runs more slowly than before (30% or more, depending on the pattern). I
303        hope this isn't a big issue. There is no effect on runtime performance.
305    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
306        newline (only possible for the last line of a file) and it was a
307        pattern that set a locale (followed by /Lsomething), pcretest crashed.
309    19. Added additional timing features to pcretest. (1) The -tm option now times
310        matching only, not compiling. (2) Both -t and -tm can be followed, as a
311        separate command line item, by a number that specifies the number of
312        repeats to use when timing. The default is 50000; this gives better
313        precision, but takes uncomfortably long for very large patterns.
315    20. Extended pcre_study() to be more clever in cases where a branch of a
316        subpattern has no definite first character. For example, (a*|b*)[cd] would
317        previously give no result from pcre_study(). Now it recognizes that the
318        first character must be a, b, c, or d.
320    21. There was an incorrect error "recursive call could loop indefinitely" if
321        a subpattern (or the entire pattern) that was being tested for matching an
322        empty string contained only one non-empty item after a nested subpattern.
323        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
324        incorrectly, because the \d was being skipped in the check.
326    22. The pcretest program now has a new pattern option /B and a command line
327        option -b, which is equivalent to adding /B to every pattern. This causes
328        it to show the compiled bytecode, without the additional information that
329        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
330        is the same as /B/I).
332    23. A new optimization is now able automatically to treat some sequences such
333        as a*b as a*+b. More specifically, if something simple (such as a character
334        or a simple class like \d) has an unlimited quantifier, and is followed by
335        something that cannot possibly match the quantified thing, the quantifier
336        is automatically "possessified".
338    24. A recursive reference to a subpattern whose number was greater than 39
339        went wrong under certain circumstances in UTF-8 mode. This bug could also
340        have affected the operation of pcre_study().
342    25. Realized that a little bit of performance could be had by replacing
343        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
345    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
347    27. Possessive quantifiers such as a++ were previously implemented by turning
348        them into atomic groups such as ($>a+). Now they have their own opcodes,
349        which improves performance. This includes the automatically created ones
350        from 23 above.
352    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
353        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
354        the first matched character to be a colon. This applied both to named and
355        numbered groups.
357    29. The ucpinternal.h header file was missing its idempotency #ifdef.
359    30. I was sent a "project" file called libpcre.a.dev which I understand makes
360        building PCRE on Windows easier, so I have included it in the distribution.
362    31. There is now a check in pcretest against a ridiculously large number being
363        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
364        loop, the loop is abandoned.
366    32. Forward references to subpatterns in conditions such as (?(2)...) where
367        subpattern 2 is defined later cause pcre_compile() to search forwards in
368        the pattern for the relevant set of parentheses. This search went wrong
369        when there were unescaped parentheses in a character class, parentheses
370        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
372    33. "Subroutine" calls and backreferences were previously restricted to
373        referencing subpatterns earlier in the regex. This restriction has now
374        been removed.
376    34. Added a number of extra features that are going to be in Perl 5.10. On the
377        whole, these are just syntactic alternatives for features that PCRE had
378        previously implemented using the Python syntax or my own invention. The
379        other formats are all retained for compatibility.
381        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
382            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
383            also .NET compatible.
385        (b) A recursion or subroutine call to a named group can now be defined as
386            (?&name) as well as (?P>name).
388        (c) A backreference to a named group can now be defined as \k<name> or
389            \k'name' as well as (?P=name). The new forms, as well as being in Perl
390            5.10, are also .NET compatible.
392        (d) A conditional reference to a named group can now use the syntax
393            (?(<name>) or (?('name') as well as (?(name).
395        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
396            groups (named and numbered) that are never evaluated inline, but can be
397            called as "subroutines" from elsewhere. In effect, the DEFINE condition
398            is always false. There may be only one alternative in such a group.
400        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
401            as the simple (?(R). The condition is true only if the most recent
402            recursion is that of the given number or name. It does not search out
403            through the entire recursion stack.
405        (g) The escape \gN or \g{N} has been added, where N is a positive or
406            negative number, specifying an absolute or relative reference.
408    35. Tidied to get rid of some further signed/unsigned compiler warnings and
409        some "unreachable code" warnings.
411    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
412        things, this adds five new scripts.
414    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
415        There were also incompatibilities regarding the handling of \Q..\E inside
416        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
417        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
419    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
420        matches an empty string, and forcibly breaks the loop. There were bugs in
421        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
422        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
423        separate and independent bugs (that affected different cases) have been
424        fixed.
426    39. Refactored the code to abolish the use of different opcodes for small
427        capturing bracket numbers. This is a tidy that I avoided doing when I
428        removed the limit on the number of capturing brackets for 3.5 back in 2001.
429        The new approach is not only tidier, it makes it possible to reduce the
430        memory needed to fix the previous bug (38).
432    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
433        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
434        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
435        mode.
437    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
438        report.
440    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
441        copy construction and assignment in the C++ wrapper.
443    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
444        couple of bugs that could have given wrong results in the "--newline=crlf"
445        case.
447    44. Added a number of casts and did some reorganization of signed/unsigned int
448        variables following suggestions from Dair Grant. Also renamed the variable
449        "this" as "item" because it is a C++ keyword.
451    45. Arranged for dftables to add
453          #include "pcre_internal.h"
455        to pcre_chartables.c because without it, gcc 4.x may remove the array
456        definition from the final binary if PCRE is built into a static library and
457        dead code stripping is activated.
459    46. For an unanchored pattern, if a match attempt fails at the start of a
460        newline sequence, and the newline setting is CRLF or ANY, and the next two
461        characters are CRLF, advance by two characters instead of one.
464    Version 6.7 04-Jul-06
465    ---------------------
467     1. In order to handle tests when input lines are enormously long, pcretest has
468        been re-factored so that it automatically extends its buffers when
469        necessary. The code is crude, but this _is_ just a test program. The
470        default size has been increased from 32K to 50K.
472     2. The code in pcre_study() was using the value of the re argument before
473        testing it for NULL. (Of course, in any sensible call of the function, it
474        won't be NULL.)
476     3. The memmove() emulation function in pcre_internal.h, which is used on
477        systems that lack both memmove() and bcopy() - that is, hardly ever -
478        was missing a "static" storage class specifier.
480     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
481        containing an extended class (one that cannot be represented by a bitmap
482        because it contains high-valued characters or Unicode property items, e.g.
483        [\pZ]). Almost always one would set UTF-8 mode when processing such a
484        pattern, but PCRE should not loop if you do not (it no longer does).
485        [Detail: two cases were found: (a) a repeated subpattern containing an
486        extended class; (b) a recursive reference to a subpattern that followed a
487        previous extended class. It wasn't skipping over the extended class
488        correctly when UTF-8 mode was not set.]
490     5. A negated single-character class was not being recognized as fixed-length
491        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
492        compile error "lookbehind assertion is not fixed length".
494     6. The RunPerlTest auxiliary script was showing an unexpected difference
495        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
496        write a Perl script that can interpret lines of an input file either as
497        byte characters or as UTF-8, which is what "perltest" was being required to
498        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
499        can't do is switch easily at run time between having the "use utf8;" pragma
500        or not. In the end, I fudged it by using the RunPerlTest script to insert
501        "use utf8;" explicitly for the UTF-8 tests.
503     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
504        the end of the subject string, contrary to the documentation and to what
505        Perl does. This was true of both matching functions. Now it matches only at
506        the start of the subject and immediately after *internal* newlines.
508     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
509        a pointer to an int instead of a pointer to an unsigned long int. This
510        caused problems on 64-bit systems.
512     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
513        instance of the 'standard' template library not being so standard".
515    10. There was no check on the number of named subpatterns nor the maximum
516        length of a subpattern name. The product of these values is used to compute
517        the size of the memory block for a compiled pattern. By supplying a very
518        long subpattern name and a large number of named subpatterns, the size
519        computation could be caused to overflow. This is now prevented by limiting
520        the length of names to 32 characters, and the number of named subpatterns
521        to 10,000.
523    11. Subpatterns that are repeated with specific counts have to be replicated in
524        the compiled pattern. The size of memory for this was computed from the
525        length of the subpattern and the repeat count. The latter is limited to
526        65535, but there was no limit on the former, meaning that integer overflow
527        could in principle occur. The compiled length of a repeated subpattern is
528        now limited to 30,000 bytes in order to prevent this.
530    12. Added the optional facility to have named substrings with the same name.
532    13. Added the ability to use a named substring as a condition, using the
533        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
534        are numbers (not recommended). Forward references are permitted.
536    14. Added forward references in named backreferences (if you see what I mean).
538    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
539        pattern could run off the end of the subject. For example, the pattern
540        "(?s)(.{1,5})"8 did this with the subject "ab".
542    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
543        PCRE_CASELESS was set when matching characters that were quantified with ?
544        or *.
546    17. A character class other than a single negated character that had a minimum
547        but no maximum quantifier - for example [ab]{6,} - was not handled
548        correctly by pce_dfa_exec(). It would match only one character.
550    18. A valid (though odd) pattern that looked like a POSIX character
551        class but used an invalid character after [ (for example [[,abc,]]) caused
552        pcre_compile() to give the error "Failed: internal error: code overflow" or
553        in some cases to crash with a glibc free() error. This could even happen if
554        the pattern terminated after [[ but there just happened to be a sequence of
555        letters, a binary zero, and a closing ] in the memory that followed.
557    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
558        over the years. Originally (before any Unicode support), just the bottom 8
559        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
560        output from "man perlunicode" includes this:
562          The regular expression compiler produces polymorphic opcodes.  That
563          is, the pattern adapts to the data and automatically switches to
564          the Unicode character scheme when presented with Unicode data--or
565          instead uses a traditional byte scheme when presented with byte
566          data.
568        Sadly, a wide octal escape does not cause a switch, and in a string with
569        no other multibyte characters, these octal escapes are treated as before.
570        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
571        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
572        Unicode string.
574        I have not perpetrated such confusion in PCRE. Up till now, it took just
575        the bottom 8 bits, as in old Perl. I have now made octal escapes with
576        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
577        translate to the appropriate multibyte character.
579    29. Applied some refactoring to reduce the number of warnings from Microsoft
580        and Borland compilers. This has included removing the fudge introduced
581        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
582        a warning about an unused variable.
584    21. PCRE has not included VT (character 0x0b) in the set of whitespace
585        characters since release 4.0, because Perl (from release 5.004) does not.
586        [Or at least, is documented not to: some releases seem to be in conflict
587        with the documentation.] However, when a pattern was studied with
588        pcre_study() and all its branches started with \s, PCRE still included VT
589        as a possible starting character. Of course, this did no harm; it just
590        caused an unnecessary match attempt.
592    22. Removed a now-redundant internal flag bit that recorded the fact that case
593        dependency changed within the pattern. This was once needed for "required
594        byte" processing, but is no longer used. This recovers a now-scarce options
595        bit. Also moved the least significant internal flag bit to the most-
596        significant bit of the word, which was not previously used (hangover from
597        the days when it was an int rather than a uint) to free up another bit for
598        the future.
600    23. Added support for CRLF line endings as well as CR and LF. As well as the
601        default being selectable at build time, it can now be changed at runtime
602        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
603        specify that it is scanning data with non-default line endings.
605    24. Changed the definition of CXXLINK to make it agree with the definition of
606        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
608    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
609        recursions. This makes a big different to stack usage for some patterns.
611    26. If a subpattern containing a named recursion or subroutine reference such
612        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
613        the space required for the compiled pattern went wrong and gave too small a
614        value. Depending on the environment, this could lead to "Failed: internal
615        error: code overflow at offset 49" or "glibc detected double free or
616        corruption" errors.
618    27. Applied patches from Google (a) to support the new newline modes and (b) to
619        advance over multibyte UTF-8 characters in GlobalReplace.
621    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
622        difference for some implementation of PCRE in some Windows version.
624    29. Added some extra testing facilities to pcretest:
626        \q<number>   in a data line sets the "match limit" value
627        \Q<number>   in a data line sets the "match recursion limt" value
628        -S <number>  sets the stack size, where <number> is in megabytes
630        The -S option isn't available for Windows.
633    Version 6.6 06-Feb-06
634    ---------------------
636     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
637        in pcreposix.h. I have copied the definition from pcre.h.
639     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
640        because pcre.h is no longer a built file.
642     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
643        not normally included in the compiled code.
646    Version 6.5 01-Feb-06
647    ---------------------
649     1. When using the partial match feature with pcre_dfa_exec(), it was not
650        anchoring the second and subsequent partial matches at the new starting
651        point. This could lead to incorrect results. For example, with the pattern
652        /1234/, partially matching against "123" and then "a4" gave a match.
654     2. Changes to pcregrep:
656        (a) All non-match returns from pcre_exec() were being treated as failures
657            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
658            error message is output. Some extra information is given for the
659            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
660            probably the only errors that are likely to be caused by users (by
661            specifying a regex that has nested indefinite repeats, for instance).
662            If there are more than 20 of these errors, pcregrep is abandoned.
664        (b) A binary zero was treated as data while matching, but terminated the
665            output line if it was written out. This has been fixed: binary zeroes
666            are now no different to any other data bytes.
668        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
669            used to set a locale for matching. The --locale=xxxx long option has
670            been added (no short equivalent) to specify a locale explicitly on the
671            pcregrep command, overriding the environment variables.
673        (d) When -B was used with -n, some line numbers in the output were one less
674            than they should have been.
676        (e) Added the -o (--only-matching) option.
678        (f) If -A or -C was used with -c (count only), some lines of context were
679            accidentally printed for the final match.
681        (g) Added the -H (--with-filename) option.
683        (h) The combination of options -rh failed to suppress file names for files
684            that were found from directory arguments.
686        (i) Added the -D (--devices) and -d (--directories) options.
688        (j) Added the -F (--fixed-strings) option.
690        (k) Allow "-" to be used as a file name for -f as well as for a data file.
692        (l) Added the --colo(u)r option.
694        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
695            is not present by default.
697     3. A nasty bug was discovered in the handling of recursive patterns, that is,
698        items such as (?R) or (?1), when the recursion could match a number of
699        alternatives. If it matched one of the alternatives, but subsequently,
700        outside the recursion, there was a failure, the code tried to back up into
701        the recursion. However, because of the way PCRE is implemented, this is not
702        possible, and the result was an incorrect result from the match.
704        In order to prevent this happening, the specification of recursion has
705        been changed so that all such subpatterns are automatically treated as
706        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
708     4. I had overlooked the fact that, in some locales, there are characters for
709        which isalpha() is true but neither isupper() nor islower() are true. In
710        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
711        and ordfeminine) are like this. This affected the treatment of \w and \W
712        when they appeared in character classes, but not when they appeared outside
713        a character class. The bit map for "word" characters is now created
714        separately from the results of isalnum() instead of just taking it from the
715        upper, lower, and digit maps. (Plus the underscore character, of course.)
717     5. The above bug also affected the handling of POSIX character classes such as
718        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
719        permanent tables. Instead, the bit maps for such a class were previously
720        created as the appropriate unions of the upper, lower, and digit bitmaps.
721        Now they are created by subtraction from the [[:word:]] class, which has
722        its own bitmap.
724     6. The [[:blank:]] character class matches horizontal, but not vertical space.
725        It is created by subtracting the vertical space characters (\x09, \x0a,
726        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
727        subtraction was done in the overall bitmap for a character class, meaning
728        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
729        be recognized. This bug has been fixed.
731     7. Patches from the folks at Google:
733          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
734          real life, but is still worth protecting against".
736          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
737          regular expressions".
739          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
740          have it.
742          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
743          "configure" and the latter not, in order to fix a problem somebody had
744          with compiling the Arg class on HP-UX.
746          (e) Improve the error-handling of the C++ wrapper a little bit.
748          (f) New tests for checking recursion limiting.
750     8. The pcre_memmove() function, which is used only if the environment does not
751        have a standard memmove() function (and is therefore rarely compiled),
752        contained two bugs: (a) use of int instead of size_t, and (b) it was not
753        returning a result (though PCRE never actually uses the result).
755     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
756        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
757        returned instead of calling malloc() with an overflowing number that would
758        most likely cause subsequent chaos.
760    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
762    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
763        with this option is matched, the nmatch and pmatch options of regexec() are
764        ignored.
766    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
767        provided in case anyone wants to the the POSIX interface with UTF-8
768        strings.
770    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
771        C++ linking (needed for some HP-UX environments).
773    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
774        (unused parameter) and in the pcre_printint() function (omitted "default"
775        switch label when the default is to do nothing).
777    15. Added some code to make it possible, when PCRE is compiled as a C++
778        library, to replace subject pointers for pcre_exec() with a smart pointer
779        class, thus making it possible to process discontinuous strings.
781    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
782        much the same function. They were added by different people who were trying
783        to make PCRE easy to compile on non-Unix systems. It has been suggested
784        that PCRE_EXPORT be abolished now that there is more automatic apparatus
785        for compiling on Windows systems. I have therefore replaced it with
786        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
787        defaults to "extern" for C or "extern C" for C++, which works fine on
788        Unix-like systems. It is now possible to override the value of PCRE_DATA_
789        SCOPE with something explicit in config.h. In addition:
791        (a) pcreposix.h still had just "extern" instead of either of these macros;
792            I have replaced it with PCRE_DATA_SCOPE.
794        (b) Functions such as _pcre_xclass(), which are internal to the library,
795            but external in the C sense, all had PCRE_EXPORT in their definitions.
796            This is apparently wrong for the Windows case, so I have removed it.
797            (It makes no difference on Unix-like systems.)
799    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
800        of recursive calls to match(). This is different to MATCH_LIMIT because
801        that limits the total number of calls to match(), not all of which increase
802        the depth of recursion. Limiting the recursion depth limits the amount of
803        stack (or heap if NO_RECURSE is set) that is used. The default can be set
804        when PCRE is compiled, and changed at run time. A patch from Google adds
805        this functionality to the C++ interface.
807    18. Changes to the handling of Unicode character properties:
809        (a) Updated the table to Unicode 4.1.0.
811        (b) Recognize characters that are not in the table as "Cn" (undefined).
813        (c) I revised the way the table is implemented to a much improved format
814            which includes recognition of ranges. It now supports the ranges that
815            are defined in UnicodeData.txt, and it also amalgamates other
816            characters into ranges. This has reduced the number of entries in the
817            table from around 16,000 to around 3,000, thus reducing its size
818            considerably. I realized I did not need to use a tree structure after
819            all - a binary chop search is just as efficient. Having reduced the
820            number of entries, I extended their size from 6 bytes to 8 bytes to
821            allow for more data.
823        (d) Added support for Unicode script names via properties such as \p{Han}.
825    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
826        matching that character.
828    20. When matching a repeated Unicode property with a minimum greater than zero,
829        (for example \pL{2,}), PCRE could look past the end of the subject if it
830        reached it while seeking the minimum number of characters. This could
831        happen only if some of the characters were more than one byte long, because
832        there is a check for at least the minimum number of bytes.
834    21. Refactored the implementation of \p and \P so as to be more general, to
835        allow for more different types of property in future. This has changed the
836        compiled form incompatibly. Anybody with saved compiled patterns that use
837        \p or \P will have to recompile them.
839    22. Added "Any" and "L&" to the supported property types.
841    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
842        but give a compile time error if the value is greater than 0xff.
844    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
845        accidentally not being installed or uninstalled.
847    25. The pcre.h file was built from pcre.h.in, but the only changes that were
848        made were to insert the current release number. This seemed silly, because
849        it made things harder for people building PCRE on systems that don't run
850        "configure". I have turned pcre.h into a distributed file, no longer built
851        by "configure", with the version identification directly included. There is
852        no longer a pcre.h.in file.
854        However, this change necessitated a change to the pcre-config script as
855        well. It is built from pcre-config.in, and one of the substitutions was the
856        release number. I have updated configure.ac so that ./configure now finds
857        the release number by grepping pcre.h.
859    26. Added the ability to run the tests under valgrind.
862    Version 6.4 05-Sep-05
863    ---------------------
865     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
866        "--" to be printed when multiple files were scanned, even when none of the
867        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
868        consider it to be a bug, and have restored the previous behaviour.
870     2. A couple of code tidies to get rid of compiler warnings.
872     3. The pcretest program used to cheat by referring to symbols in the library
873        whose names begin with _pcre_. These are internal symbols that are not
874        really supposed to be visible externally, and in some environments it is
875        possible to suppress them. The cheating is now confined to including
876        certain files from the library's source, which is a bit cleaner.
878     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
879        file's purpose clearer.
881     5. Reorganized pcre_ucp_findchar().
884    Version 6.3 15-Aug-05
885    ---------------------
887     1. The file libpcre.pc.in did not have general read permission in the tarball.
889     2. There were some problems when building without C++ support:
891        (a) If C++ support was not built, "make install" and "make test" still
892            tried to test it.
894        (b) There were problems when the value of CXX was explicitly set. Some
895            changes have been made to try to fix these, and ...
897        (c) --disable-cpp can now be used to explicitly disable C++ support.
899        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
900            backslash in a target when C++ was disabled. This confuses some
901            versions of "make", apparently. Using an intermediate variable solves
902            this. (Same for CPP_LOBJ.)
904     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
905        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
906        necessary on certain architectures.
908     4. Added a setting of -export-symbols-regex to the link command to remove
909        those symbols that are exported in the C sense, but actually are local
910        within the library, and not documented. Their names all begin with
911        "_pcre_". This is not a perfect job, because (a) we have to except some
912        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
913        available (and never for static libraries). I have made a note to try to
914        find a way round (a) in the future.
917    Version 6.2 01-Aug-05
918    ---------------------
920     1. There was no test for integer overflow of quantifier values. A construction
921        such as {1111111111111111} would give undefined results. What is worse, if
922        a minimum quantifier for a parenthesized subpattern overflowed and became
923        negative, the calculation of the memory size went wrong. This could have
924        led to memory overwriting.
926     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
928     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
929        operating environments where this matters.
931     4. Applied Giuseppe Maxia's patch to add additional features for controlling
932        PCRE options from within the C++ wrapper.
934     5. Named capturing subpatterns were not being correctly counted when a pattern
935        was compiled. This caused two problems: (a) If there were more than 100
936        such subpatterns, the calculation of the memory needed for the whole
937        compiled pattern went wrong, leading to an overflow error. (b) Numerical
938        back references of the form \12, where the number was greater than 9, were
939        not recognized as back references, even though there were sufficient
940        previous subpatterns.
942     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
943        versions of gcc, e.g. 2.95.4.
946    Version 6.1 21-Jun-05
947    ---------------------
949     1. There was one reference to the variable "posix" in pcretest.c that was not
950        surrounded by "#if !defined NOPOSIX".
952     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
953        the cross-check on the old pcre_info() function, for the benefit of the
954        cut-down version of PCRE that is currently imported into Exim.
956     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
957        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
958        patterns that start (?i) but I don't think that matters. The use of (?i) is
959        just an example; this all applies to the other options as well.
961     4. Since libtool seems to echo the compile commands it is issuing, the output
962        from "make" can be reduced a bit by putting "@" in front of each libtool
963        compile command.
965     5. Patch from the folks at Google for configure.in to be a bit more thorough
966        in checking for a suitable C++ installation before trying to compile the
967        C++ stuff. This should fix a reported problem when a compiler was present,
968        but no suitable headers.
970     6. The man pages all had just "PCRE" as their title. I have changed them to
971        be the relevant file name. I have also arranged that these names are
972        retained in the file doc/pcre.txt, which is a concatenation in text format
973        of all the man pages except the little individual ones for each function.
975     7. The NON-UNIX-USE file had not been updated for the different set of source
976        files that come with release 6. I also added a few comments about the C++
977        wrapper.
980    Version 6.0 07-Jun-05
981    ---------------------
983     1. Some minor internal re-organization to help with my DFA experiments.
985     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
986        didn't matter for the library itself when fully configured, but did matter
987        when compiling without UCP support, or within Exim, where the ucp files are
988        not imported.
990     3. Refactoring of the library code to split up the various functions into
991        different source modules. The addition of the new DFA matching code (see
992        below) to a single monolithic source would have made it really too
993        unwieldy, quite apart from causing all the code to be include in a
994        statically linked application, when only some functions are used. This is
995        relevant even without the DFA addition now that patterns can be compiled in
996        one application and matched in another.
998        The downside of splitting up is that there have to be some external
999        functions and data tables that are used internally in different modules of
1000        the library but which are not part of the API. These have all had their
1001        names changed to start with "_pcre_" so that they are unlikely to clash
1002        with other external names.
1004     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1005        a different (DFA) algorithm. Although it is slower than the original
1006        function, it does have some advantages for certain types of matching
1007        problem.
1009     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1010        including restarting after a partial match.
1012     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1013        defined when compiling for Windows was sent to me. I have put it into the
1014        code, though I have no means of testing or verifying it.
1016     7. Added the pcre_refcount() auxiliary function.
1018     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1019        match before or at the first newline in the subject string. In pcretest,
1020        the /f option on a pattern can be used to set this.
1022     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1023        would behave wrongly. This has been present in PCRE since release 4.0.
1025    10. A number of changes to the pcregrep command:
1027        (a) Refactored how -x works; insert ^(...)$ instead of setting
1028            PCRE_ANCHORED and checking the length, in preparation for adding
1029            something similar for -w.
1031        (b) Added the -w (match as a word) option.
1033        (c) Refactored the way lines are read and buffered so as to have more
1034            than one at a time available.
1036        (d) Implemented a pcregrep test script.
1038        (e) Added the -M (multiline match) option. This allows patterns to match
1039            over several lines of the subject. The buffering ensures that at least
1040            8K, or the rest of the document (whichever is the shorter) is available
1041            for matching (and similarly the previous 8K for lookbehind assertions).
1043        (f) Changed the --help output so that it now says
1045              -w, --word-regex(p)
1047            instead of two lines, one with "regex" and the other with "regexp"
1048            because that confused at least one person since the short forms are the
1049            same. (This required a bit of code, as the output is generated
1050            automatically from a table. It wasn't just a text change.)
1052        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1053            option but starts with a hyphen. Could be a pattern or a path name
1054            starting with a hyphen, for instance.
1056        (h) "-" can be given as a file name to represent stdin.
1058        (i) When file names are being printed, "(standard input)" is used for
1059            the standard input, for compatibility with GNU grep. Previously
1060            "<stdin>" was used.
1062        (j) The option --label=xxx can be used to supply a name to be used for
1063            stdin when file names are being printed. There is no short form.
1065        (k) Re-factored the options decoding logic because we are going to add
1066            two more options that take data. Such options can now be given in four
1067            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1069        (l) Added the -A, -B, and -C options for requesting that lines of context
1070            around matches be printed.
1072        (m) Added the -L option to print the names of files that do not contain
1073            any matching lines, that is, the complement of -l.
1075        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1076            continue to scan other files.
1078        (o) The -s option was incorrectly implemented. For compatibility with other
1079            greps, it now suppresses the error message for a non-existent or non-
1080            accessible file (but not the return code). There is a new option called
1081            -q that suppresses the output of matching lines, which was what -s was
1082            previously doing.
1084        (p) Added --include and --exclude options to specify files for inclusion
1085            and exclusion when recursing.
1087    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1088        Hopefully, it now does.
1090    12. Missing cast in pcre_study().
1092    13. Added an "uninstall" target to the makefile.
1094    14. Replaced "extern" in the function prototypes in Makefile.in with
1095        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1096        world, but is set differently for Windows.
1098    15. Added a second compiling function called pcre_compile2(). The only
1099        difference is that it has an extra argument, which is a pointer to an
1100        integer error code. When there is a compile-time failure, this is set
1101        non-zero, in addition to the error test pointer being set to point to an
1102        error message. The new argument may be NULL if no error number is required
1103        (but then you may as well call pcre_compile(), which is now just a
1104        wrapper). This facility is provided because some applications need a
1105        numeric error indication, but it has also enabled me to tidy up the way
1106        compile-time errors are handled in the POSIX wrapper.
1108    16. Added VPATH=.libs to the makefile; this should help when building with one
1109        prefix path and installing with another. (Or so I'm told by someone who
1110        knows more about this stuff than I do.)
1112    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1113        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1114        match everything, including newlines. This is not POSIX-compatible, but
1115        somebody wanted the feature. From pcretest it can be activated by using
1116        both the P and the s flags.
1118    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1120    19. libpcre.pc was being incorrectly installed as executable.
1122    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1123        it now also looks for '\r' so that it will work unmodified on Windows.
1125    21. Added Google's contributed C++ wrapper to the distribution.
1127    22. Added some untidy missing memory free() calls in pcretest, to keep
1128        Electric Fence happy when testing.
1132    Version 5.0 13-Sep-04
1133    ---------------------
1135     1. Internal change: literal characters are no longer packed up into items
1136        containing multiple characters in a single byte-string. Each character
1137        is now matched using a separate opcode. However, there may be more than one
1138        byte in the character in UTF-8 mode.
1140     2. The pcre_callout_block structure has two new fields: pattern_position and
1141        next_item_length. These contain the offset in the pattern to the next match
1142        item, and its length, respectively.
1144     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1145        insertion of callouts before each pattern item. Added the /C option to
1146        pcretest to make use of this.
1148     4. On the advice of a Windows user, the lines
1150          #if defined(_WIN32) || defined(WIN32)
1151          _setmode( _fileno( stdout ), 0x8000 );
1152          #endif  /* defined(_WIN32) || defined(WIN32) */
1154        have been added to the source of pcretest. This apparently does useful
1155        magic in relation to line terminators.
1157     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1158        for the benefit of those environments where the "b" makes a difference.
1160     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1161        to know about it. I have put a hack into configure.in that adds in code
1162        to set GCC=yes if CC=icc. This seems to end up at a point in the
1163        generated configure script that is early enough to affect the setting of
1164        compiler options, which is what is needed, but I have no means of testing
1165        whether it really works. (The user who reported this had patched the
1166        generated configure script, which of course I cannot do.)
1168        LATER: After change 22 below (new libtool files), the configure script
1169        seems to know about icc (and also ecc). Therefore, I have commented out
1170        this hack in configure.in.
1172     7. Added support for pkg-config (2 patches were sent in).
1174     8. Negated POSIX character classes that used a combination of internal tables
1175        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1176        [[:^ascii]]. Typically, they would match almost any characters. The other
1177        POSIX classes were not broken in this way.
1179     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1180        to find the match, as PCRE was deluded into thinking that the match had to
1181        start at the start point or following a newline. The same bug applied to
1182        patterns with negative forward assertions or any backward assertions
1183        preceding ".*" at the start, unless the pattern required a fixed first
1184        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1186    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1187        starting at the last subject character, bytes beyond the end of the subject
1188        string were read.
1190    11. Renamed the variable "class" as "classbits" to make life easier for C++
1191        users. (Previously there was a macro definition, but it apparently wasn't
1192        enough.)
1194    12. Added the new field "tables" to the extra data so that tables can be passed
1195        in at exec time, or the internal tables can be re-selected. This allows
1196        a compiled regex to be saved and re-used at a later time by a different
1197        program that might have everything at different addresses.
1199    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1200        -R library as well as a -L library.
1202    14. The debugging options of pcretest (-d on the command line or D on a
1203        pattern) showed incorrect output for anything following an extended class
1204        that contained multibyte characters and which was followed by a quantifier.
1206    15. Added optional support for general category Unicode character properties
1207        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1208        support. It adds about 90K to the size of the library. The meanings of the
1209        inbuilt class escapes such as \d and \s have NOT been changed.
1211    16. Updated pcredemo.c to include calls to free() to release the memory for the
1212        compiled pattern.
1214    17. The generated file chartables.c was being created in the source directory
1215        instead of in the building directory. This caused the build to fail if the
1216        source directory was different from the building directory, and was
1217        read-only.
1219    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1220        file. No doubt somebody will tell me if they don't make sense... Also added
1221        Dan Mooney's comments about building on OpenVMS.
1223    19. Added support for partial matching via the PCRE_PARTIAL option for
1224        pcre_exec() and the \P data escape in pcretest.
1226    20. Extended pcretest with 3 new pattern features:
1228        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1229              write the compiled pattern to the file whose name is "rest-of-line".
1230              This is a straight binary dump of the data, with the saved pointer to
1231              the character tables forced to be NULL. The study data, if any, is
1232              written too. After writing, pcretest reads a new pattern.
1234        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1235              compiled pattern from the given file. There must not be any
1236              occurrences of "<" in the file name (pretty unlikely); if there are,
1237              pcretest will instead treat the initial "<" as a pattern delimiter.
1238              After reading in the pattern, pcretest goes on to read data lines as
1239              usual.
1241        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1242              and 16-bit fields in a compiled pattern, to simulate a pattern that
1243              was compiled on a host of opposite endianness.
1245    21. The pcre-exec() function can now cope with patterns that were compiled on
1246        hosts of opposite endianness, with this restriction:
1248          As for any compiled expression that is saved and used later, the tables
1249          pointer field cannot be preserved; the extra_data field in the arguments
1250          to pcre_exec() should be used to pass in a tables address if a value
1251          other than the default internal tables were used at compile time.
1253    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1254        now diagnosed as an error. Previously, most of the time, a negative number
1255        would have been treated as zero, but if in addition "ovector" was passed as
1256        NULL, a crash could occur.
1258    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1259        new versions from the libtool 1.5 distribution (the last one is a copy of
1260        a file called libtool.m4). This seems to have fixed the need to patch
1261        "configure" to support Darwin 1.3 (which I used to do). However, I still
1262        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1263        workstation).
1265    24. Changed the PCRE licence to be the more standard "BSD" licence.
1268    Version 4.5 01-Dec-03
1269    ---------------------
1271     1. There has been some re-arrangement of the code for the match() function so
1272        that it can be compiled in a version that does not call itself recursively.
1273        Instead, it keeps those local variables that need separate instances for
1274        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1275        needs to "recurse". Keeping track of where control must go is done by means
1276        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1277        hide most of the details from the main code, and operates only if
1278        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1279        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1280        operating.
1282        To make it easier for callers to provide specially tailored get/free
1283        functions for this usage, two new functions, pcre_stack_malloc, and
1284        pcre_stack_free, are used. They are always called in strict stacking order,
1285        and the size of block requested is always the same.
1287        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1288        PCRE has been compiled to use the stack or the heap for recursion. The
1289        -C option of pcretest uses this to show which version is compiled.
1291        A new data escape \S, is added to pcretest; it causes the amounts of store
1292        obtained and freed by both kinds of malloc/free at match time to be added
1293        to the output.
1295     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1296        what's available on my current Linux desktop machine.
1298     3. When matching a UTF-8 string, the test for a valid string at the start has
1299        been extended. If start_offset is not zero, PCRE now checks that it points
1300        to a byte that is the start of a UTF-8 character. If not, it returns
1301        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1302        this is necessary because there may be backward assertions in the pattern.
1303        When matching the same subject several times, it may save resources to use
1304        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1306     4. The code for checking the validity of UTF-8 strings has been tightened so
1307        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1308        containing "overlong sequences".
1310     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1311        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1312        should have been "&", but it just so happened that all the cases this let
1313        through by mistake were picked up later in the function.
1315     6. I had used a variable called "isblank" - this is a C99 function, causing
1316        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1318     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1319        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1320        so the version is shown; (c) stop "make test" echoing "./RunTest".
1322     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1324     9. The prototype for memmove() for systems that don't have it was using
1325        size_t, but the inclusion of the header that defines size_t was later. I've
1326        moved the #includes for the C headers earlier to avoid this.
1328    10. Added some adjustments to the code to make it easier to compiler on certain
1329        special systems:
1331          (a) Some "const" qualifiers were missing.
1332          (b) Added the macro EXPORT before all exported functions; by default this
1333              is defined to be empty.
1334          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1335              that it reads its output file name as an argument instead of writing
1336              to the standard output and assuming this can be redirected.
1338    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1339        class containing characters with values greater than 255, PCRE compilation
1340        went into a loop.
1342    12. A recursive reference to a subpattern that was within another subpattern
1343        that had a minimum quantifier of zero caused PCRE to crash. For example,
1344        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1345        recursion. If the recursively-called subpattern itself had a zero repeat,
1346        that was OK.
1348    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1349        buffer into which it was copied (for escape processing) was still set at
1350        1024, so long lines caused crashes.
1352    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1353        "internal error: code overflow...". This applied to any character class
1354        that was followed by a possessive quantifier.
1356    15. Modified the Makefile to add libpcre.la as a prerequisite for
1357        libpcreposix.la because I was told this is needed for a parallel build to
1358        work.
1360    16. If a pattern that contained .* following optional items at the start was
1361        studied, the wrong optimizing data was generated, leading to matching
1362        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1363        matching string must start with a or b or c. The correct conclusion for
1364        this pattern is that a match can start with any character.
1367    Version 4.4 13-Aug-03
1368    ---------------------
1370     1. In UTF-8 mode, a character class containing characters with values between
1371        127 and 255 was not handled correctly if the compiled pattern was studied.
1372        In fixing this, I have also improved the studying algorithm for such
1373        classes (slightly).
1375     2. Three internal functions had redundant arguments passed to them. Removal
1376        might give a very teeny performance improvement.
1378     3. Documentation bug: the value of the capture_top field in a callout is *one
1379        more than* the number of the hightest numbered captured substring.
1381     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1382        in incorrectly linking with a previously installed version. They now link
1383        explicitly with libpcre.la.
1385     5. configure.in no longer needs to recognize Cygwin specially.
1387     6. A problem in pcre.in for Windows platforms is fixed.
1389     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1390        pcretest, it used to include the size of the study block as part of its
1391        output. Unfortunately, the structure contains a field that has a different
1392        size on different hardware architectures. This meant that the tests that
1393        showed this size failed. As the block is currently always of a fixed size,
1394        this information isn't actually particularly useful in pcretest output, so
1395        I have just removed it.
1397     8. Three pre-processor statements accidentally did not start in column 1.
1398        Sadly, there are *still* compilers around that complain, even though
1399        standard C has not required this for well over a decade. Sigh.
1401     9. In pcretest, the code for checking callouts passed small integers in the
1402        callout_data field, which is a void * field. However, some picky compilers
1403        complained about the casts involved for this on 64-bit systems. Now
1404        pcretest passes the address of the small integer instead, which should get
1405        rid of the warnings.
1407    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1408        both compile and run time, and gives an error if an invalid UTF-8 sequence
1409        is found. There is a option for disabling this check in cases where the
1410        string is known to be correct and/or the maximum performance is wanted.
1412    11. In response to a bug report, I changed one line in Makefile.in from
1414            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1415        to
1416            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1418        to look similar to other lines, but I have no way of telling whether this
1419        is the right thing to do, as I do not use Windows. No doubt I'll get told
1420        if it's wrong...
1423    Version 4.3 21-May-03
1424    ---------------------
1426    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1427       Makefile.
1429    2. Some refactoring to improve the quality of the code:
1431       (i)   The utf8_table... variables are now declared "const".
1433       (ii)  The code for \cx, which used the "case flipping" table to upper case
1434             lower case letters, now just substracts 32. This is ASCII-specific,
1435             but the whole concept of \cx is ASCII-specific, so it seems
1436             reasonable.
1438       (iii) PCRE was using its character types table to recognize decimal and
1439             hexadecimal digits in the pattern. This is silly, because it handles
1440             only 0-9, a-f, and A-F, but the character types table is locale-
1441             specific, which means strange things might happen. A private
1442             table is now used for this - though it costs 256 bytes, a table is
1443             much faster than multiple explicit tests. Of course, the standard
1444             character types table is still used for matching digits in subject
1445             strings against \d.
1447       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1448             ending in _t are). So I've renamed it as ESC_tee.
1450    3. The first argument for regexec() in the POSIX wrapper should have been
1451       defined as "const".
1453    4. Changed pcretest to use malloc() for its buffers so that they can be
1454       Electric Fenced for debugging.
1456    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1457       to read one or more bytes before the start of the subject string. Often this
1458       had no effect on PCRE's behaviour, but in some circumstances it could
1459       provoke a segmentation fault.
1461    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1462       to try to read one or more bytes before the start of the subject string.
1464    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1465       UTF-8 support could misbehave in various ways if the subject string
1466       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1467       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1468       back over UTF-8 characters.)
1471    Version 4.2 14-Apr-03
1472    ---------------------
1474    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1476    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1477         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1478         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1479         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1480         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1481           and BUILD_EXEEXT
1482         Note: automatic setting of the BUILD variables is not yet working
1483         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1484           compile-time but not at link-time
1485         [LINK]: use for linking executables only
1486         make different versions for Windows and non-Windows
1487         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1488           libraries
1489         [LINK_FOR_BUILD]: new variable
1490         [OBJEXT]: use throughout
1491         [EXEEXT]: use throughout
1492         <winshared>: new target
1493         <wininstall>: new target
1494         <dftables.o>: use native compiler
1495         <dftables>: use native linker
1496         <install>: handle Windows platform correctly
1497         <clean>: ditto
1498         <check>: ditto
1499         copy DLL to top builddir before testing
1501       As part of these changes, -no-undefined was removed again. This was reported
1502       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1503       in any case.
1505    3. Some tidies to get rid of compiler warnings:
1507       . In the match_data structure, match_limit was an unsigned long int, whereas
1508         match_call_count was an int. I've made them both unsigned long ints.
1510       . In pcretest the fact that a const uschar * doesn't automatically cast to
1511         a void * provoked a warning.
1513       . Turning on some more compiler warnings threw up some "shadow" variables
1514         and a few more missing casts.
1516    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1517       option, a class that contained a single character with a value between 128
1518       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1520    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1521       option, a class that contained several characters, but with at least one
1522       whose value was between 128 and 255 caused PCRE to crash.
1525    Version 4.1 12-Mar-03
1526    ---------------------
1528    1. Compiling with gcc -pedantic found a couple of places where casts were
1529    needed, and a string in dftables.c that was longer than standard compilers are
1530    required to support.
1532    2. Compiling with Sun's compiler found a few more places where the code could
1533    be tidied up in order to avoid warnings.
1535    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1536    first of these names is deprecated in the latest Autoconf in favour of the name
1537    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1538    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1539    analogy I have changed it to CFLAGS_FOR_BUILD.
1541    4. Added -no-undefined to the linking command in the Makefile, because this is
1542    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1543    linking step for the pcreposix library.
1545    5. PCRE was failing to diagnose the case of two named groups with the same
1546    name.
1548    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1549    literal character that is needed in the subject for a match, and scans along to
1550    ensure that it is present before embarking on the full matching process. This
1551    saves time in cases of nested unlimited repeats that are never going to match.
1552    Problem: the scan can take a lot of time if the subject is very long (e.g.
1553    megabytes), thus penalizing straightforward matches. It is now done only if the
1554    amount of subject to be scanned is less than 1000 bytes.
1556    7. A lesser problem with the same optimization is that it was recording the
1557    first character of an anchored pattern as "needed", thus provoking a search
1558    right along the subject, even when the first match of the pattern was going to
1559    fail. The "needed" character is now not set for anchored patterns, unless it
1560    follows something in the pattern that is of non-fixed length. Thus, it still
1561    fulfils its original purpose of finding quick non-matches in cases of nested
1562    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1565    Version 4.0 17-Feb-03
1566    ---------------------
1568    1. If a comment in an extended regex that started immediately after a meta-item
1569    extended to the end of string, PCRE compiled incorrect data. This could lead to
1570    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1572    2. Moved to autoconf 2.53 and libtool 1.4.2.
1574    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1575    the special perltest8 script is no longer needed - all the tests can be run
1576    from a single perltest script.
1578    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1579    by \s. It has now been removed in PCRE. This means it isn't recognized as
1580    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1581    class [:space:] *does* include VT, thereby creating a mess.
1583    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1584    space and tab.
1586    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1587    its new features into the main test script, reducing the number of scripts.
1589    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1590    were backward compatible, and made the (?i) apply to the whole pattern, as if
1591    /i were given. Now it behaves more logically, and applies the option setting
1592    only to what follows. PCRE has been changed to follow suit. However, if it
1593    finds options settings right at the start of the pattern, it extracts them into
1594    the global options, as before. Thus, they show up in the info data.
1596    8. Added support for the \Q...\E escape sequence. Characters in between are
1597    treated as literals. This is slightly different from Perl in that $ and @ are
1598    also handled as literals inside the quotes. In Perl, they will cause variable
1599    interpolation. Note the following examples:
1601        Pattern            PCRE matches      Perl matches
1603        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1604        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1605        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1607    For compatibility with Perl, \Q...\E sequences are recognized inside character
1608    classes as well as outside them.
1610    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1611    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1612    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1613    signed/unsigned warnings.
1615    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1616    option for pcretest, so I've replaced it by a simple function that does just
1617    that job.
1619    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1620    "pcregrep -".
1622    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1623    Java package. This provides some syntactic sugar for simple cases of what my
1624    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1625    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1626    item, you can use this simplified notation. Note that only makes sense with
1627    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1628    greediness, whatever the setting of the PCRE_UNGREEDY option.
1630    13. A change of greediness default within a pattern was not taking effect at
1631    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1632    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1633    was abstracted outside.
1635    14. PCRE now supports the \G assertion. It is true when the current matching
1636    position is at the start point of the match. This differs from \A when the
1637    starting offset is non-zero. Used with the /g option of pcretest (or similar
1638    code), it works in the same way as it does for Perl's /g option. If all
1639    alternatives of a regex begin with \G, the expression is anchored to the start
1640    match position, and the "anchored" flag is set in the compiled expression.
1642    15. Some bugs concerning the handling of certain option changes within patterns
1643    have been fixed. These applied to options other than (?ims). For example,
1644    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1645    been the other way round. Some of this was related to change 7 above.
1647    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1648    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1649    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1650    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1652    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1653    mode. Unlike ".", it always matches newline, whatever the setting of
1654    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1655    assertions. Perl allows it, but it doesn't (in general) work because it can't
1656    calculate the length of the lookbehind. At least, that's the case for Perl
1657    5.8.0 - I've been told they are going to document that it doesn't work in
1658    future.
1660    18. Added an error diagnosis for escapes that PCRE does not support: these are
1661    \L, \l, \N, \P, \p, \U, \u, and \X.
1663    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1664    reading past the end of the pattern in cases such as /[abcd/.
1666    20. PCRE was getting more memory than necessary for patterns with classes that
1667    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1669    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1670    compiling PCRE for use with Virtual Pascal.
1672    22. Small fix to the Makefile to make it work properly if the build is done
1673    outside the source tree.
1675    23. Added a new extension: a condition to go with recursion. If a conditional
1676    subpattern starts with (?(R) the "true" branch is used if recursion has
1677    happened, whereas the "false" branch is used only at the top level.
1679    24. When there was a very long string of literal characters (over 255 bytes
1680    without UTF support, over 250 bytes with UTF support), the computation of how
1681    much memory was required could be incorrect, leading to segfaults or other
1682    strange effects.
1684    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1685    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1686    there was a subsequent back reference to those brackets. This meant that, for
1687    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1688    possible to check for precisely this case. All we can do is abandon the
1689    optimization if .* occurs inside capturing brackets when there are any back
1690    references whatsoever. (See below for a better fix that came later.)
1692    26. The handling of the optimization for finding the first character of a
1693    non-anchored pattern, and for finding a character that is required later in the
1694    match were failing in some cases. This didn't break the matching; it just
1695    failed to optimize when it could. The way this is done has been re-implemented.
1697    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1699    28. Added a new feature that provides some of the functionality that Perl
1700    provides with (?{...}). The facility is termed a "callout". The way it is done
1701    in PCRE is for the caller to provide an optional function, by setting
1702    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1703    global variable. By default it is unset, which disables all calling out. To get
1704    the function called, the regex must include (?C) at appropriate points. This
1705    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1706    This provides a means of identifying different callout points. When PCRE
1707    reaches such a point in the regex, if pcre_callout has been set, the external
1708    function is called. It is provided with data in a structure called
1709    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1710    matching continues; if it returns a non-zero value, the match at the current
1711    point fails. However, backtracking will occur if possible. [This was changed
1712    later and other features added - see item 49 below.]
1714    29. pcretest is upgraded to test the callout functionality. It provides a
1715    callout function that displays information. By default, it shows the start of
1716    the match and the current position in the text. There are some new data escapes
1717    to vary what happens:
1719        \C+         in addition, show current contents of captured substrings
1720        \C-         do not supply a callout function
1721        \C!n        return 1 when callout number n is reached
1722        \C!n!m      return 1 when callout number n is reached for the mth time
1724    30. If pcregrep was called with the -l option and just a single file name, it
1725    output "<stdin>" if a match was found, instead of the file name.
1727    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1728    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1729    pcre_exec(). This saves a malloc/free per call. The default value of
1730    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1731    when configuring.
1733    32. The default maximum size of a compiled pattern is 64K. There have been a
1734    few cases of people hitting this limit. The code now uses macros to handle the
1735    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1736    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1737    configuring. Tests 2 and 5 work only with 2-byte links because they output
1738    debugging information about compiled patterns.
1740    33. Internal code re-arrangements:
1742    (a) Moved the debugging function for printing out a compiled regex into
1743        its own source file (printint.c) and used #include to pull it into
1744        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1745        separate copies.
1747    (b) Defined the list of op-code names for debugging as a macro in
1748        internal.h so that it is next to the definition of the opcodes.
1750    (c) Defined a table of op-code lengths for simpler skipping along compiled
1751        code. This is again a macro in internal.h so that it is next to the
1752        definition of the opcodes.
1754    34. Added support for recursive calls to individual subpatterns, along the
1755    lines of Robin Houston's patch (but implemented somewhat differently).
1757    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1758    allow it to read and process whole directories in Win32. This code was
1759    contributed by Lionel Fourquaux; it has not been tested by me.
1761    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1762    used to name a group. Names consist of alphanumerics and underscores, and must
1763    be unique. Back references use the syntax (?P=name) and recursive calls use
1764    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1765    numbers. The function pcre_fullinfo() can be used after compilation to extract
1766    a name/number map. There are three relevant calls:
1768      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1769      PCRE_INFO_NAMECOUNT            yields the number of entries
1770      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1772    The map is a vector of fixed-size entries. The size of each entry depends on
1773    the length of the longest name used. The first two bytes of each entry are the
1774    group number, most significant byte first. There follows the corresponding
1775    name, zero terminated. The names are in alphabetical order.
1777    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1778    case instead of 255. Making it the same both with and without UTF-8 support
1779    means that the same test output works with both.
1781    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1782    calling malloc() with a zero argument.
1784    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1785    optimization. I've improved things by keeping a bitmap of backreferences with
1786    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1787    fact referenced, the optimization can be applied. It is unlikely that a
1788    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1789    the match to follow \n) will appear inside brackets with a number greater than
1790    31, but if it does, any back reference > 31 suppresses the optimization.
1792    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1793    of disabling numbered capturing parentheses. Any opening parenthesis that is
1794    not followed by ? behaves as if it were followed by ?: but named parentheses
1795    can still be used for capturing (and they will acquire numbers in the usual
1796    way).
1798    41. Redesigned the return codes from the match() function into yes/no/error so
1799    that errors can be passed back from deep inside the nested calls. A malloc
1800    failure while inside a recursive subpattern call now causes the
1801    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1803    42. It is now possible to set a limit on the number of times the match()
1804    function is called in a call to pcre_exec(). This facility makes it possible to
1805    limit the amount of recursion and backtracking, though not in a directly
1806    obvious way, because the match() function is used in a number of different
1807    circumstances. The count starts from zero for each position in the subject
1808    string (for non-anchored patterns). The default limit is, for compatibility, a
1809    large number, namely 10 000 000. You can change this in two ways:
1811    (a) When configuring PCRE before making, you can use --with-match-limit=n
1812        to set a default value for the compiled library.
1814    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1815        a different value is set. See 45 below.
1817    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1819    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1820    of things that can be changed at compile time. The first argument specifies
1821    what is wanted and the second points to where the information is to be placed.
1822    The current list of available information is:
1824      PCRE_CONFIG_UTF8
1826    The output is an integer that is set to one if UTF-8 support is available;
1827    otherwise it is set to zero.
1831    The output is an integer that it set to the value of the code that is used for
1832    newline. It is either LF (10) or CR (13).
1836    The output is an integer that contains the number of bytes used for internal
1837    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1841    The output is an integer that contains the threshold above which the POSIX
1842    interface uses malloc() for output vectors. See item 31 above.
1846    The output is an unsigned integer that contains the default limit of the number
1847    of match() calls in a pcre_exec() execution. See 42 above.
1849    44. pcretest has been upgraded by the addition of the -C option. This causes it
1850    to extract all the available output from the new pcre_config() function, and to
1851    output it. The program then exits immediately.
1853    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1854    order to support additional features. One way would have been to define
1855    pcre_exec2() (for example) with extra arguments, but this would not have been
1856    extensible, and would also have required all calls to the original function to
1857    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1858    is used for passing in "extra" data from pcre_study().
1860    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1861    contains the following fields:
1863      flags         a bitmap indicating which of the following fields are set
1864      study_data    opaque data from pcre_study()
1865      match_limit   a way of specifying a limit on match() calls for a specific
1866                      call to pcre_exec()
1867      callout_data  data for callouts (see 49 below)
1869    The flag bits are also defined in pcre.h, and are
1875    The pcre_study() function now returns one of these new pcre_extra blocks, with
1876    the actual study data pointed to by the study_data field, and the
1877    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1878    before. That is, this change is entirely upwards-compatible and requires no
1879    change to existing code.
1881    If you want to pass in additional data to pcre_exec(), you can either place it
1882    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1883    block.
1885    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1886    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1887    times with different match limits, until it finds the minimum value needed for
1888    pcre_exec() to complete. The value is then output. This can be instructive; for
1889    most simple matches the number is quite small, but for pathological cases it
1890    gets very large very quickly.
1892    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1893    returns the size of the data block pointed to by the study_data field in a
1894    pcre_extra block, that is, the value that was passed as the argument to
1895    pcre_malloc() when PCRE was getting memory in which to place the information
1896    created by pcre_study(). The fourth argument should point to a size_t variable.
1897    pcretest has been extended so that this information is shown after a successful
1898    pcre_study() call when information about the compiled regex is being displayed.
1900    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
1901    because what follows is always an absolute path. (Later: it turns out that this
1902    is more than cosmetic for MinGW, because it doesn't like empty path
1903    components.)
1905    49. Some changes have been made to the callout feature (see 28 above):
1907    (i)  A callout function now has three choices for what it returns:
1909           0  =>  success, carry on matching
1910         > 0  =>  failure at this point, but backtrack if possible
1911         < 0  =>  serious error, return this value from pcre_exec()
1913         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
1914         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
1915         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
1916         use by callout functions. It will never be used by PCRE itself.
1918    (ii) The pcre_extra structure (see 45 above) has a void * field called
1919         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
1920         pcre_callout_block structure has a field of the same name. The contents of
1921         the field passed in the pcre_extra structure are passed to the callout
1922         function in the corresponding field in the callout block. This makes it
1923         easier to use the same callout-containing regex from multiple threads. For
1924         testing, the pcretest program has a new data escape
1926           \C*n        pass the number n (may be negative) as callout_data
1928         If the callout function in pcretest receives a non-zero value as
1929         callout_data, it returns that value.
1931    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
1932    there were some redundant $(CFLAGS) in commands that are now specified as
1933    $(LINK), which already includes $(CFLAGS).
1935    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
1936    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
1937    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
1938    one-byte characters throughout. Note that case-insensitive matching applies
1939    only to characters whose values are less than 256. PCRE doesn't support the
1940    notion of cases for higher-valued characters.
1942    (i)   A character class whose characters are all within 0-255 is handled as
1943          a bit map, and the map is inverted for negative classes. Previously, a
1944          character > 255 always failed to match such a class; however it should
1945          match if the class was a negative one (e.g. [^ab]). This has been fixed.
1947    (ii)  A negated character class with a single character < 255 is coded as
1948          "not this character" (OP_NOT). This wasn't working properly when the test
1949          character was multibyte, either singly or repeated.
1951    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
1952          mode, for example: \x{100}{2,3}.
1954    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
1955          singly or repeated) now correctly test multibyte characters. However,
1956          PCRE doesn't recognize any characters with values greater than 255 as
1957          digits, spaces, or word characters. Such characters always match \D, \S,
1958          and \W, and never match \d, \s, or \w.
1960    (v)   Classes may now contain characters and character ranges with values
1961          greater than 255. For example: [ab\x{100}-\x{400}].
1963    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
1964          PCRE in UTF-8 mode.
1966    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
1967    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
1968    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
1969    value.)
1971    53. The single man page has become too large. I have therefore split it up into
1972    a number of separate man pages. These also give rise to individual HTML pages;
1973    these are now put in a separate directory, and there is an index.html page that
1974    lists them all. Some hyperlinking between the pages has been installed.
1976    54. Added convenience functions for handling named capturing parentheses.
1978    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
1979    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
1980    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
1981    are faulted.
1983    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
1984    calling configure. These values are used when compiling the dftables.c program
1985    which is run to generate the source of the default character tables. They
1986    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
1987    you will need to set these values.
1989    57. Updated the building process for Windows DLL, as provided by Fred Cox.
1992    Version 3.9 02-Jan-02
1993    ---------------------
1995    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
1997    2. If --disable-static was given, the building process failed when trying to
1998    build pcretest and pcregrep. (For some reason it was using libtool to compile
1999    them, which is not right, as they aren't part of the library.)
2002    Version 3.8 18-Dec-01
2003    ---------------------
2005    1. The experimental UTF-8 code was completely screwed up. It was packing the
2006    bytes in the wrong order. How dumb can you get?
2009    Version 3.7 29-Oct-01
2010    ---------------------
2012    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2013    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2014    this didn't happen under Solaris 8, where I normally test things.
2016    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2017    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2018    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2019    this fix an hour or so after the initial 3.7 release.)
2022    Version 3.6 23-Oct-01
2023    ---------------------
2025    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2026    offsets passed as NULL with zero offset count.
2028    2. The config.guess and config.sub files had not been updated when I moved to
2029    the latest autoconf.
2032    Version 3.5 15-Aug-01
2033    ---------------------
2035    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2036    had been forgotten.
2038    2. By using declared but undefined structures, we can avoid using "void"
2039    definitions in pcre.h while keeping the internal definitions of the structures
2040    private.
2042    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2043    user point of view, this means that both static and shared libraries are built
2044    by default, but this can be individually controlled. More of the work of
2045    handling this static/shared cases is now inside libtool instead of PCRE's make
2046    file.
2048    4. The pcretest utility is now installed along with pcregrep because it is
2049    useful for users (to test regexs) and by doing this, it automatically gets
2050    relinked by libtool. The documentation has been turned into a man page, so
2051    there are now .1, .txt, and .html versions in /doc.
2053    5. Upgrades to pcregrep:
2054       (i)   Added long-form option names like gnu grep.
2055       (ii)  Added --help to list all options with an explanatory phrase.
2056       (iii) Added -r, --recursive to recurse into sub-directories.
2057       (iv)  Added -f, --file to read patterns from a file.
2059    6. pcre_exec() was referring to its "code" argument before testing that
2060    argument for NULL (and giving an error if it was NULL).
2062    7. Upgraded Makefile.in to allow for compiling in a different directory from
2063    the source directory.
2065    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2066    options bits, the pointer it was passed was to an int instead of to an unsigned
2067    long int. This mattered only on 64-bit systems.
2069    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2070    generated) instead of pcre.in, which it its source. Also made the same change
2071    in several of the .c files.
2073    10. A new release of gcc defines printf() as a macro, which broke pcretest
2074    because it had an ifdef in the middle of a string argument for printf(). Fixed
2075    by using separate calls to printf().
2077    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2078    script, to force use of CR or LF instead of \n in the source. On non-Unix
2079    systems, the value can be set in config.h.
2081    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2082    absolute limit. Changed the text of the error message to make this clear, and
2083    likewise updated the man page.
2085    13. The limit of 99 on the number of capturing subpatterns has been removed.
2086    The new limit is 65535, which I hope will not be a "real" limit.
2089    Version 3.4 22-Aug-00
2090    ---------------------
2092    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2094    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2097    Version 3.3 01-Aug-00
2098    ---------------------
2100    1. If an octal character was given, but the value was greater than \377, it
2101    was not getting masked to the least significant bits, as documented. This could
2102    lead to crashes in some systems.
2104    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2105    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2107    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2108    These just pass their arguments on to (pcre_free)(), but they are provided
2109    because some uses of PCRE bind it to non-C systems that can call its functions,
2110    but cannot call free() or pcre_free() directly.
2112    4. Add "make test" as a synonym for "make check". Corrected some comments in
2113    the Makefile.
2115    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2116    Makefile.
2118    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2119    command called pgrep for grepping around the active processes.
2121    7. Added the beginnings of support for UTF-8 character strings.
2123    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2124    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2125    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2126    out for the ar command.)
2129    Version 3.2 12-May-00
2130    ---------------------
2132    This is purely a bug fixing release.
2134    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2135    of ZA. This was just one example of several cases that could provoke this bug,
2136    which was introduced by change 9 of version 2.00. The code for breaking
2137    infinite loops after an iteration that matches an empty string was't working
2138    correctly.
2140    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2141    when matched against abbab (for example). After matching an empty string, it
2142    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2143    caused it to match further down the string than it should.
2145    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2146    was there because it doesn't seem to be needed, and it causes trouble on some
2147    systems, as it is not a Standard C header. It has been removed.
2149    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2150    were reported on the Macintosh. The changes were from
2152      while ((c = *(++ptr)) != 0 && c != '\n');
2153    to
2154      while ((c = *(++ptr)) != 0 && c != '\n') ;
2156    Totally extraordinary, but if that's what it takes...
2158    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2159    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2160    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2161    assumes the way PCRE uses memmove() (always moving upwards).
2163    6. PCRE is being used in one environment where strchr() is not available. There
2164    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2165    faster code anyway.
2168    Version 3.1 09-Feb-00
2169    ---------------------
2171    The only change in this release is the fixing of some bugs in Makefile.in for
2172    the "install" target:
2174    (1) It was failing to install pcreposix.h.
2176    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2179    Version 3.0 01-Feb-00
2180    ---------------------
2182    1. Add support for the /+ modifier to perltest (to output $` like it does in
2183    pcretest).
2185    2. Add support for the /g modifier to perltest.
2187    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2188    matches null strings.
2190    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2191    pattern. Perl treats empty patterns specially - it reuses the most recent
2192    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2193    effect.
2195    5. The POSIX interface was broken in that it was just handing over the POSIX
2196    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2197    required a bigger vector, with some working space on the end. This means that
2198    the POSIX wrapper now has to get and free some memory, and copy the results.
2200    6. Added some simple autoconf support, placing the test data and the
2201    documentation in separate directories, re-organizing some of the
2202    information files, and making it build pcre-config (a GNU standard). Also added
2203    libtool support for building PCRE as a shared library, which is now the
2204    default.
2206    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2207    09 are not valid octal constants. Single digits will be used for minor values
2208    less than 10.
2210    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2211    existing programs that set these in the POSIX interface can use PCRE without
2212    modification.
2214    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2215    return all that pcre_info() returns, plus additional data. The pcre_info()
2216    function is retained for compatibility, but is considered to be obsolete.
2218    10. Added experimental recursion feature (?R) to handle one common case that
2219    Perl 5.6 will be able to do with (?p{...}).
2221    11. Added support for POSIX character classes like [:alpha:], which Perl is
2222    adopting.
2225    Version 2.08 31-Aug-99
2226    ----------------------
2228    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2229    trying to match at the startoffset position, but instead was moving forward to
2230    the next newline as if a previous match had failed.
2232    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2233    and could get into a loop if a null string was matched other than at the start
2234    of the subject.
2236    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2237    be distinguished at compile time, and for completeness also added PCRE_DATE.
2239    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2240    in GnuWin32 environments.
2243    Version 2.07 29-Jul-99
2244    ----------------------
2246    1. The documentation is now supplied in plain text form and HTML as well as in
2247    the form of man page sources.
2249    2. C++ compilers don't like assigning (void *) values to other pointer types.
2250    In particular this affects malloc(). Although there is no problem in Standard
2251    C, I've put in casts to keep C++ compilers happy.
2253    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2254    should be (const char *).
2256    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2257    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2258    However, I haven't made this a standard facility. The documentation doesn't
2259    mention it, and the Makefile doesn't support it.
2261    5. The Makefile now contains an "install" target, with editable destinations at
2262    the top of the file. The pcretest program is not installed.
2264    6. pgrep -V now gives the PCRE version number and date.
2266    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2267    causing the entire string to be ignored, instead of just the last character.
2269    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2270    non-matching string, it can take a very, very long time, even for strings of
2271    quite modest length, because of the nested recursion. PCRE now does better in
2272    some of these cases. It does this by remembering the last required literal
2273    character in the pattern, and pre-searching the subject to ensure it is present
2274    before running the real match. In other words, it applies a heuristic to detect
2275    some types of certain failure quickly, and in the above example, if presented
2276    with a string that has no trailing " it gives "no match" very quickly.
2278    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2279    other alternatives are tried instead.
2282    Version 2.06 09-Jun-99
2283    ----------------------
2285    1. Change pcretest's output for amount of store used to show just the code
2286    space, because the remainder (the data block) varies in size between 32-bit and
2287    64-bit systems.
2289    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2290    start matching at. This allows lookbehinds to work when searching for multiple
2291    occurrences in a string.
2293    3. Added additional options to pcretest for testing multiple occurrences:
2295       /+   outputs the rest of the string that follows a match
2296       /g   loops for multiple occurrences, using the new startoffset argument
2297       /G   loops for multiple occurrences by passing an incremented pointer
2299    4. PCRE wasn't doing the "first character" optimization for patterns starting
2300    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2301    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2302    the letter 'x'. On long subject strings, this gives a significant speed-up.
2305    Version 2.05 21-Apr-99
2306    ----------------------
2308    1. Changed the type of magic_number from int to long int so that it works
2309    properly on 16-bit systems.
2311    2. Fixed a bug which caused patterns starting with .* not to work correctly
2312    when the subject string contained newline characters. PCRE was assuming
2313    anchoring for such patterns in all cases, which is not correct because .* will
2314    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2315    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2316    must be retried after every newline in the subject.
2319    Version 2.04 18-Feb-99
2320    ----------------------
2322    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2323    computation of the store needed to hold the pattern was incorrect (too large).
2324    If such patterns were nested a few deep, this could multiply and become a real
2325    problem.
2327    2. Added /M option to pcretest to show the memory requirement of a specific
2328    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2330    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2331    compiled in such a way that the backtracking after subsequent failure was
2332    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2333    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2336    Version 2.03 02-Feb-99
2337    ----------------------
2339    1. Fixed typo and small mistake in man page.
2341    2. Added 4th condition (GPL supersedes if conflict) and created separate
2342    LICENCE file containing the conditions.
2344    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2345    Perl, that is the internal \ allows the delimiter to be included in the
2346    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2347    the final delimiter, add \ to the end of the pattern (to test the error).
2349    4. Added the convenience functions for extracting substrings after a successful
2350    match. Updated pcretest to make it able to test these functions.
2353  Version 2.02 14-Jan-99  Version 2.02 14-Jan-99
2354  ----------------------  ----------------------

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