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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.1 05-Mar-07
5    ---------------------
7     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
8        that is more "standard", making use of automake and other autotools. There
9        is some re-arrangement of the files and adjustment of comments consequent
10        on this.
12     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
13        for recursive directory scanning broke on some systems because the files
14        are not scanned in any specific order and on different systems the order
15        was different. A call to "sort" has been inserted into RunGrepTest for the
16        approprate test as a short-term fix. In the longer term there may be an
17        alternative.
19     3. I had an email from Eric Raymond about problems translating some of PCRE's
20        man pages to HTML (despite the fact that I distribute HTML pages, some
21        people do their own conversions for various reasons). The problems
22        concerned the use of low-level troff macros .br and .in. I have therefore
23        removed all such uses from the man pages (some were redundant, some could
24        be replaced by .nf/.fi pairs). The maintain/132html script that I use to
25        generate HTML has been updated to handle .nf/.fi and to complain if it
26        encounters .br or .in.
28     4. Updated comments in configure.ac that get placed in config.h.in and also
29        arranged for config.h to be included in the distribution, for the benefit
30        of those who have to compile without Autotools (compare pcre.h).
32     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
33        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
34        makevp.bat for the current PCRE, using the additional files !compile.txt,
35        !linklib.txt, and pcregexp.pas.
37     6. A Windows user reported a minor discrepancy with test 2, which turned out
38        to be caused by a trailing space on an input line that had got lost in his
39        copy. The trailing space was an accident, so I've just removed it.
41     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
42        that is needed.
44     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
45        as "const" (a) because they are and (b) because it helps the PHP
46        maintainers who have recently made a script to detect big data structures
47        in the php code that should be moved to the .rodata section. I remembered
48        to update Builducptable as well, so it won't revert if ucptable.h is ever
49        re-created.
51     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
52        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
53        order to be able to cut out the UTF-8 tables in the latter when UTF-8
54        support is not required. This saves 1.5-2K of code, which is important in
55        some applications.
57        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
58        so as not to refer to the tables, even though these functions will never be
59        called when UTF-8 support is disabled. Otherwise there are problems with a
60        shared library.
62    10. The emulated memmove() function in pcre_internal.h (provided for those
63        environments that have neither memmove() nor bcopy()) was defining its
64        arguments as char * instead of void *.
67    Version 7.0 19-Dec-06
68    ---------------------
70     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
71        moving to gcc 4.1.1.
73     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
74        sys/time.h, which is documented as needed for this function. It doesn't
75        seem to matter on Linux, but it showed up on some releases of OS X.
77     3. It seems that there are systems where bytes whose values are greater than
78        127 match isprint() in the "C" locale. The "C" locale should be the
79        default when a C program starts up. In most systems, only ASCII printing
80        characters match isprint(). This difference caused the output from pcretest
81        to vary, making some of the tests fail. I have changed pcretest so that:
83        (a) When it is outputting text in the compiled version of a pattern, bytes
84            other than 32-126 are always shown as hex escapes.
86        (b) When it is outputting text that is a matched part of a subject string,
87            it does the same, unless a different locale has been set for the match
88            (using the /L modifier). In this case, it uses isprint() to decide.
90     4. Fixed a major bug that caused incorrect computation of the amount of memory
91        required for a compiled pattern when options that changed within the
92        pattern affected the logic of the preliminary scan that determines the
93        length. The relevant options are -x, and -i in UTF-8 mode. The result was
94        that the computed length was too small. The symptoms of this bug were
95        either the PCRE error "internal error: code overflow" from pcre_compile(),
96        or a glibc crash with a message such as "pcretest: free(): invalid next
97        size (fast)". Examples of patterns that provoked this bug (shown in
98        pcretest format) are:
100          /(?-x: )/x
101          /(?x)(?-x: \s*#\s*)/
102          /((?i)[\x{c0}])/8
103          /(?i:[\x{c0}])/8
105        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
106        is now done differently.
108     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
109        wrapper classes; (b) implement a new function in the C++ scanner that is
110        more efficient than the old way of doing things because it avoids levels of
111        recursion in the regex matching; (c) add a paragraph to the documentation
112        for the FullMatch() function.
114     6. The escape sequence \n was being treated as whatever was defined as
115        "newline". Not only was this contrary to the documentation, which states
116        that \n is character 10 (hex 0A), but it also went horribly wrong when
117        "newline" was defined as CRLF. This has been fixed.
119     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
120        was being set to -1 for the "end of line" case (supposedly a value that no
121        character can have). Though this value is never used (the check for end of
122        line is "zero bytes in current character"), it caused compiler complaints.
123        I've changed it to 0xffffffff.
125     8. In pcre_version.c, the version string was being built by a sequence of
126        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
127        string (as it is for production releases) called a macro with an empty
128        argument. The C standard says the result of this is undefined. The gcc
129        compiler treats it as an empty string (which was what was wanted) but it is
130        reported that Visual C gives an error. The source has been hacked around to
131        avoid this problem.
133     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
134        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
135        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
136        of them did).
138    10. Originally, pcretest opened its input and output without "b"; then I was
139        told that "b" was needed in some environments, so it was added for release
140        5.0 to both the input and output. (It makes no difference on Unix-like
141        systems.) Later I was told that it is wrong for the input on Windows. I've
142        now abstracted the modes into two macros, to make it easier to fiddle with
143        them, and removed "b" from the input mode under Windows.
145    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
147    12. Added -help and --help to pcretest as an official way of being reminded
148        of the options.
150    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
151        and pcrecpp.cc because they annoy compilers at high warning levels.
153    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
155    15. Fixed an occurrence of == in configure.ac that should have been = (shell
156        scripts are not C programs :-) and which was not noticed because it works
157        on Linux.
159    16. pcretest is supposed to handle any length of pattern and data line (as one
160        line or as a continued sequence of lines) by extending its input buffer if
161        necessary. This feature was broken for very long pattern lines, leading to
162        a string of junk being passed to pcre_compile() if the pattern was longer
163        than about 50K.
165    17. I have done a major re-factoring of the way pcre_compile() computes the
166        amount of memory needed for a compiled pattern. Previously, there was code
167        that made a preliminary scan of the pattern in order to do this. That was
168        OK when PCRE was new, but as the facilities have expanded, it has become
169        harder and harder to keep it in step with the real compile phase, and there
170        have been a number of bugs (see for example, 4 above). I have now found a
171        cunning way of running the real compile function in a "fake" mode that
172        enables it to compute how much memory it would need, while actually only
173        ever using a few hundred bytes of working memory and without too many
174        tests of the mode. This should make future maintenance and development
175        easier. A side effect of this work is that the limit of 200 on the nesting
176        depth of parentheses has been removed (though this was never a serious
177        limitation, I suspect). However, there is a downside: pcre_compile() now
178        runs more slowly than before (30% or more, depending on the pattern). I
179        hope this isn't a big issue. There is no effect on runtime performance.
181    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
182        newline (only possible for the last line of a file) and it was a
183        pattern that set a locale (followed by /Lsomething), pcretest crashed.
185    19. Added additional timing features to pcretest. (1) The -tm option now times
186        matching only, not compiling. (2) Both -t and -tm can be followed, as a
187        separate command line item, by a number that specifies the number of
188        repeats to use when timing. The default is 50000; this gives better
189        precision, but takes uncomfortably long for very large patterns.
191    20. Extended pcre_study() to be more clever in cases where a branch of a
192        subpattern has no definite first character. For example, (a*|b*)[cd] would
193        previously give no result from pcre_study(). Now it recognizes that the
194        first character must be a, b, c, or d.
196    21. There was an incorrect error "recursive call could loop indefinitely" if
197        a subpattern (or the entire pattern) that was being tested for matching an
198        empty string contained only one non-empty item after a nested subpattern.
199        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
200        incorrectly, because the \d was being skipped in the check.
202    22. The pcretest program now has a new pattern option /B and a command line
203        option -b, which is equivalent to adding /B to every pattern. This causes
204        it to show the compiled bytecode, without the additional information that
205        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
206        is the same as /B/I).
208    23. A new optimization is now able automatically to treat some sequences such
209        as a*b as a*+b. More specifically, if something simple (such as a character
210        or a simple class like \d) has an unlimited quantifier, and is followed by
211        something that cannot possibly match the quantified thing, the quantifier
212        is automatically "possessified".
214    24. A recursive reference to a subpattern whose number was greater than 39
215        went wrong under certain circumstances in UTF-8 mode. This bug could also
216        have affected the operation of pcre_study().
218    25. Realized that a little bit of performance could be had by replacing
219        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
221    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
223    27. Possessive quantifiers such as a++ were previously implemented by turning
224        them into atomic groups such as ($>a+). Now they have their own opcodes,
225        which improves performance. This includes the automatically created ones
226        from 23 above.
228    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
229        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
230        the first matched character to be a colon. This applied both to named and
231        numbered groups.
233    29. The ucpinternal.h header file was missing its idempotency #ifdef.
235    30. I was sent a "project" file called libpcre.a.dev which I understand makes
236        building PCRE on Windows easier, so I have included it in the distribution.
238    31. There is now a check in pcretest against a ridiculously large number being
239        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
240        loop, the loop is abandoned.
242    32. Forward references to subpatterns in conditions such as (?(2)...) where
243        subpattern 2 is defined later cause pcre_compile() to search forwards in
244        the pattern for the relevant set of parentheses. This search went wrong
245        when there were unescaped parentheses in a character class, parentheses
246        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
248    33. "Subroutine" calls and backreferences were previously restricted to
249        referencing subpatterns earlier in the regex. This restriction has now
250        been removed.
252    34. Added a number of extra features that are going to be in Perl 5.10. On the
253        whole, these are just syntactic alternatives for features that PCRE had
254        previously implemented using the Python syntax or my own invention. The
255        other formats are all retained for compatibility.
257        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
258            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
259            also .NET compatible.
261        (b) A recursion or subroutine call to a named group can now be defined as
262            (?&name) as well as (?P>name).
264        (c) A backreference to a named group can now be defined as \k<name> or
265            \k'name' as well as (?P=name). The new forms, as well as being in Perl
266            5.10, are also .NET compatible.
268        (d) A conditional reference to a named group can now use the syntax
269            (?(<name>) or (?('name') as well as (?(name).
271        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
272            groups (named and numbered) that are never evaluated inline, but can be
273            called as "subroutines" from elsewhere. In effect, the DEFINE condition
274            is always false. There may be only one alternative in such a group.
276        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
277            as the simple (?(R). The condition is true only if the most recent
278            recursion is that of the given number or name. It does not search out
279            through the entire recursion stack.
281        (g) The escape \gN or \g{N} has been added, where N is a positive or
282            negative number, specifying an absolute or relative reference.
284    35. Tidied to get rid of some further signed/unsigned compiler warnings and
285        some "unreachable code" warnings.
287    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
288        things, this adds five new scripts.
290    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
291        There were also incompatibilities regarding the handling of \Q..\E inside
292        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
293        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
295    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
296        matches an empty string, and forcibly breaks the loop. There were bugs in
297        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
298        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
299        separate and independent bugs (that affected different cases) have been
300        fixed.
302    39. Refactored the code to abolish the use of different opcodes for small
303        capturing bracket numbers. This is a tidy that I avoided doing when I
304        removed the limit on the number of capturing brackets for 3.5 back in 2001.
305        The new approach is not only tidier, it makes it possible to reduce the
306        memory needed to fix the previous bug (38).
308    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
309        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
310        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
311        mode.
313    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
314        report.
316    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
317        copy construction and assignment in the C++ wrapper.
319    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
320        couple of bugs that could have given wrong results in the "--newline=crlf"
321        case.
323    44. Added a number of casts and did some reorganization of signed/unsigned int
324        variables following suggestions from Dair Grant. Also renamed the variable
325        "this" as "item" because it is a C++ keyword.
327    45. Arranged for dftables to add
329          #include "pcre_internal.h"
331        to pcre_chartables.c because without it, gcc 4.x may remove the array
332        definition from the final binary if PCRE is built into a static library and
333        dead code stripping is activated.
335    46. For an unanchored pattern, if a match attempt fails at the start of a
336        newline sequence, and the newline setting is CRLF or ANY, and the next two
337        characters are CRLF, advance by two characters instead of one.
340    Version 6.7 04-Jul-06
341    ---------------------
343     1. In order to handle tests when input lines are enormously long, pcretest has
344        been re-factored so that it automatically extends its buffers when
345        necessary. The code is crude, but this _is_ just a test program. The
346        default size has been increased from 32K to 50K.
348     2. The code in pcre_study() was using the value of the re argument before
349        testing it for NULL. (Of course, in any sensible call of the function, it
350        won't be NULL.)
352     3. The memmove() emulation function in pcre_internal.h, which is used on
353        systems that lack both memmove() and bcopy() - that is, hardly ever -
354        was missing a "static" storage class specifier.
356     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
357        containing an extended class (one that cannot be represented by a bitmap
358        because it contains high-valued characters or Unicode property items, e.g.
359        [\pZ]). Almost always one would set UTF-8 mode when processing such a
360        pattern, but PCRE should not loop if you do not (it no longer does).
361        [Detail: two cases were found: (a) a repeated subpattern containing an
362        extended class; (b) a recursive reference to a subpattern that followed a
363        previous extended class. It wasn't skipping over the extended class
364        correctly when UTF-8 mode was not set.]
366     5. A negated single-character class was not being recognized as fixed-length
367        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
368        compile error "lookbehind assertion is not fixed length".
370     6. The RunPerlTest auxiliary script was showing an unexpected difference
371        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
372        write a Perl script that can interpret lines of an input file either as
373        byte characters or as UTF-8, which is what "perltest" was being required to
374        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
375        can't do is switch easily at run time between having the "use utf8;" pragma
376        or not. In the end, I fudged it by using the RunPerlTest script to insert
377        "use utf8;" explicitly for the UTF-8 tests.
379     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
380        the end of the subject string, contrary to the documentation and to what
381        Perl does. This was true of both matching functions. Now it matches only at
382        the start of the subject and immediately after *internal* newlines.
384     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
385        a pointer to an int instead of a pointer to an unsigned long int. This
386        caused problems on 64-bit systems.
388     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
389        instance of the 'standard' template library not being so standard".
391    10. There was no check on the number of named subpatterns nor the maximum
392        length of a subpattern name. The product of these values is used to compute
393        the size of the memory block for a compiled pattern. By supplying a very
394        long subpattern name and a large number of named subpatterns, the size
395        computation could be caused to overflow. This is now prevented by limiting
396        the length of names to 32 characters, and the number of named subpatterns
397        to 10,000.
399    11. Subpatterns that are repeated with specific counts have to be replicated in
400        the compiled pattern. The size of memory for this was computed from the
401        length of the subpattern and the repeat count. The latter is limited to
402        65535, but there was no limit on the former, meaning that integer overflow
403        could in principle occur. The compiled length of a repeated subpattern is
404        now limited to 30,000 bytes in order to prevent this.
406    12. Added the optional facility to have named substrings with the same name.
408    13. Added the ability to use a named substring as a condition, using the
409        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
410        are numbers (not recommended). Forward references are permitted.
412    14. Added forward references in named backreferences (if you see what I mean).
414    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
415        pattern could run off the end of the subject. For example, the pattern
416        "(?s)(.{1,5})"8 did this with the subject "ab".
418    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
419        PCRE_CASELESS was set when matching characters that were quantified with ?
420        or *.
422    17. A character class other than a single negated character that had a minimum
423        but no maximum quantifier - for example [ab]{6,} - was not handled
424        correctly by pce_dfa_exec(). It would match only one character.
426    18. A valid (though odd) pattern that looked like a POSIX character
427        class but used an invalid character after [ (for example [[,abc,]]) caused
428        pcre_compile() to give the error "Failed: internal error: code overflow" or
429        in some cases to crash with a glibc free() error. This could even happen if
430        the pattern terminated after [[ but there just happened to be a sequence of
431        letters, a binary zero, and a closing ] in the memory that followed.
433    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
434        over the years. Originally (before any Unicode support), just the bottom 8
435        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
436        output from "man perlunicode" includes this:
438          The regular expression compiler produces polymorphic opcodes.  That
439          is, the pattern adapts to the data and automatically switches to
440          the Unicode character scheme when presented with Unicode data--or
441          instead uses a traditional byte scheme when presented with byte
442          data.
444        Sadly, a wide octal escape does not cause a switch, and in a string with
445        no other multibyte characters, these octal escapes are treated as before.
446        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
447        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
448        Unicode string.
450        I have not perpetrated such confusion in PCRE. Up till now, it took just
451        the bottom 8 bits, as in old Perl. I have now made octal escapes with
452        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
453        translate to the appropriate multibyte character.
455    29. Applied some refactoring to reduce the number of warnings from Microsoft
456        and Borland compilers. This has included removing the fudge introduced
457        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
458        a warning about an unused variable.
460    21. PCRE has not included VT (character 0x0b) in the set of whitespace
461        characters since release 4.0, because Perl (from release 5.004) does not.
462        [Or at least, is documented not to: some releases seem to be in conflict
463        with the documentation.] However, when a pattern was studied with
464        pcre_study() and all its branches started with \s, PCRE still included VT
465        as a possible starting character. Of course, this did no harm; it just
466        caused an unnecessary match attempt.
468    22. Removed a now-redundant internal flag bit that recorded the fact that case
469        dependency changed within the pattern. This was once needed for "required
470        byte" processing, but is no longer used. This recovers a now-scarce options
471        bit. Also moved the least significant internal flag bit to the most-
472        significant bit of the word, which was not previously used (hangover from
473        the days when it was an int rather than a uint) to free up another bit for
474        the future.
476    23. Added support for CRLF line endings as well as CR and LF. As well as the
477        default being selectable at build time, it can now be changed at runtime
478        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
479        specify that it is scanning data with non-default line endings.
481    24. Changed the definition of CXXLINK to make it agree with the definition of
482        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
484    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
485        recursions. This makes a big different to stack usage for some patterns.
487    26. If a subpattern containing a named recursion or subroutine reference such
488        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
489        the space required for the compiled pattern went wrong and gave too small a
490        value. Depending on the environment, this could lead to "Failed: internal
491        error: code overflow at offset 49" or "glibc detected double free or
492        corruption" errors.
494    27. Applied patches from Google (a) to support the new newline modes and (b) to
495        advance over multibyte UTF-8 characters in GlobalReplace.
497    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
498        difference for some implementation of PCRE in some Windows version.
500    29. Added some extra testing facilities to pcretest:
502        \q<number>   in a data line sets the "match limit" value
503        \Q<number>   in a data line sets the "match recursion limt" value
504        -S <number>  sets the stack size, where <number> is in megabytes
506        The -S option isn't available for Windows.
509    Version 6.6 06-Feb-06
510    ---------------------
512     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
513        in pcreposix.h. I have copied the definition from pcre.h.
515     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
516        because pcre.h is no longer a built file.
518     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
519        not normally included in the compiled code.
522    Version 6.5 01-Feb-06
523    ---------------------
525     1. When using the partial match feature with pcre_dfa_exec(), it was not
526        anchoring the second and subsequent partial matches at the new starting
527        point. This could lead to incorrect results. For example, with the pattern
528        /1234/, partially matching against "123" and then "a4" gave a match.
530     2. Changes to pcregrep:
532        (a) All non-match returns from pcre_exec() were being treated as failures
533            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
534            error message is output. Some extra information is given for the
535            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
536            probably the only errors that are likely to be caused by users (by
537            specifying a regex that has nested indefinite repeats, for instance).
538            If there are more than 20 of these errors, pcregrep is abandoned.
540        (b) A binary zero was treated as data while matching, but terminated the
541            output line if it was written out. This has been fixed: binary zeroes
542            are now no different to any other data bytes.
544        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
545            used to set a locale for matching. The --locale=xxxx long option has
546            been added (no short equivalent) to specify a locale explicitly on the
547            pcregrep command, overriding the environment variables.
549        (d) When -B was used with -n, some line numbers in the output were one less
550            than they should have been.
552        (e) Added the -o (--only-matching) option.
554        (f) If -A or -C was used with -c (count only), some lines of context were
555            accidentally printed for the final match.
557        (g) Added the -H (--with-filename) option.
559        (h) The combination of options -rh failed to suppress file names for files
560            that were found from directory arguments.
562        (i) Added the -D (--devices) and -d (--directories) options.
564        (j) Added the -F (--fixed-strings) option.
566        (k) Allow "-" to be used as a file name for -f as well as for a data file.
568        (l) Added the --colo(u)r option.
570        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
571            is not present by default.
573     3. A nasty bug was discovered in the handling of recursive patterns, that is,
574        items such as (?R) or (?1), when the recursion could match a number of
575        alternatives. If it matched one of the alternatives, but subsequently,
576        outside the recursion, there was a failure, the code tried to back up into
577        the recursion. However, because of the way PCRE is implemented, this is not
578        possible, and the result was an incorrect result from the match.
580        In order to prevent this happening, the specification of recursion has
581        been changed so that all such subpatterns are automatically treated as
582        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
584     4. I had overlooked the fact that, in some locales, there are characters for
585        which isalpha() is true but neither isupper() nor islower() are true. In
586        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
587        and ordfeminine) are like this. This affected the treatment of \w and \W
588        when they appeared in character classes, but not when they appeared outside
589        a character class. The bit map for "word" characters is now created
590        separately from the results of isalnum() instead of just taking it from the
591        upper, lower, and digit maps. (Plus the underscore character, of course.)
593     5. The above bug also affected the handling of POSIX character classes such as
594        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
595        permanent tables. Instead, the bit maps for such a class were previously
596        created as the appropriate unions of the upper, lower, and digit bitmaps.
597        Now they are created by subtraction from the [[:word:]] class, which has
598        its own bitmap.
600     6. The [[:blank:]] character class matches horizontal, but not vertical space.
601        It is created by subtracting the vertical space characters (\x09, \x0a,
602        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
603        subtraction was done in the overall bitmap for a character class, meaning
604        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
605        be recognized. This bug has been fixed.
607     7. Patches from the folks at Google:
609          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
610          real life, but is still worth protecting against".
612          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
613          regular expressions".
615          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
616          have it.
618          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
619          "configure" and the latter not, in order to fix a problem somebody had
620          with compiling the Arg class on HP-UX.
622          (e) Improve the error-handling of the C++ wrapper a little bit.
624          (f) New tests for checking recursion limiting.
626     8. The pcre_memmove() function, which is used only if the environment does not
627        have a standard memmove() function (and is therefore rarely compiled),
628        contained two bugs: (a) use of int instead of size_t, and (b) it was not
629        returning a result (though PCRE never actually uses the result).
631     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
632        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
633        returned instead of calling malloc() with an overflowing number that would
634        most likely cause subsequent chaos.
636    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
638    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
639        with this option is matched, the nmatch and pmatch options of regexec() are
640        ignored.
642    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
643        provided in case anyone wants to the the POSIX interface with UTF-8
644        strings.
646    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
647        C++ linking (needed for some HP-UX environments).
649    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
650        (unused parameter) and in the pcre_printint() function (omitted "default"
651        switch label when the default is to do nothing).
653    15. Added some code to make it possible, when PCRE is compiled as a C++
654        library, to replace subject pointers for pcre_exec() with a smart pointer
655        class, thus making it possible to process discontinuous strings.
657    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
658        much the same function. They were added by different people who were trying
659        to make PCRE easy to compile on non-Unix systems. It has been suggested
660        that PCRE_EXPORT be abolished now that there is more automatic apparatus
661        for compiling on Windows systems. I have therefore replaced it with
662        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
663        defaults to "extern" for C or "extern C" for C++, which works fine on
664        Unix-like systems. It is now possible to override the value of PCRE_DATA_
665        SCOPE with something explicit in config.h. In addition:
667        (a) pcreposix.h still had just "extern" instead of either of these macros;
668            I have replaced it with PCRE_DATA_SCOPE.
670        (b) Functions such as _pcre_xclass(), which are internal to the library,
671            but external in the C sense, all had PCRE_EXPORT in their definitions.
672            This is apparently wrong for the Windows case, so I have removed it.
673            (It makes no difference on Unix-like systems.)
675    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
676        of recursive calls to match(). This is different to MATCH_LIMIT because
677        that limits the total number of calls to match(), not all of which increase
678        the depth of recursion. Limiting the recursion depth limits the amount of
679        stack (or heap if NO_RECURSE is set) that is used. The default can be set
680        when PCRE is compiled, and changed at run time. A patch from Google adds
681        this functionality to the C++ interface.
683    18. Changes to the handling of Unicode character properties:
685        (a) Updated the table to Unicode 4.1.0.
687        (b) Recognize characters that are not in the table as "Cn" (undefined).
689        (c) I revised the way the table is implemented to a much improved format
690            which includes recognition of ranges. It now supports the ranges that
691            are defined in UnicodeData.txt, and it also amalgamates other
692            characters into ranges. This has reduced the number of entries in the
693            table from around 16,000 to around 3,000, thus reducing its size
694            considerably. I realized I did not need to use a tree structure after
695            all - a binary chop search is just as efficient. Having reduced the
696            number of entries, I extended their size from 6 bytes to 8 bytes to
697            allow for more data.
699        (d) Added support for Unicode script names via properties such as \p{Han}.
701    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
702        matching that character.
704    20. When matching a repeated Unicode property with a minimum greater than zero,
705        (for example \pL{2,}), PCRE could look past the end of the subject if it
706        reached it while seeking the minimum number of characters. This could
707        happen only if some of the characters were more than one byte long, because
708        there is a check for at least the minimum number of bytes.
710    21. Refactored the implementation of \p and \P so as to be more general, to
711        allow for more different types of property in future. This has changed the
712        compiled form incompatibly. Anybody with saved compiled patterns that use
713        \p or \P will have to recompile them.
715    22. Added "Any" and "L&" to the supported property types.
717    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
718        but give a compile time error if the value is greater than 0xff.
720    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
721        accidentally not being installed or uninstalled.
723    25. The pcre.h file was built from pcre.h.in, but the only changes that were
724        made were to insert the current release number. This seemed silly, because
725        it made things harder for people building PCRE on systems that don't run
726        "configure". I have turned pcre.h into a distributed file, no longer built
727        by "configure", with the version identification directly included. There is
728        no longer a pcre.h.in file.
730        However, this change necessitated a change to the pcre-config script as
731        well. It is built from pcre-config.in, and one of the substitutions was the
732        release number. I have updated configure.ac so that ./configure now finds
733        the release number by grepping pcre.h.
735    26. Added the ability to run the tests under valgrind.
738    Version 6.4 05-Sep-05
739    ---------------------
741     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
742        "--" to be printed when multiple files were scanned, even when none of the
743        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
744        consider it to be a bug, and have restored the previous behaviour.
746     2. A couple of code tidies to get rid of compiler warnings.
748     3. The pcretest program used to cheat by referring to symbols in the library
749        whose names begin with _pcre_. These are internal symbols that are not
750        really supposed to be visible externally, and in some environments it is
751        possible to suppress them. The cheating is now confined to including
752        certain files from the library's source, which is a bit cleaner.
754     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
755        file's purpose clearer.
757     5. Reorganized pcre_ucp_findchar().
760    Version 6.3 15-Aug-05
761    ---------------------
763     1. The file libpcre.pc.in did not have general read permission in the tarball.
765     2. There were some problems when building without C++ support:
767        (a) If C++ support was not built, "make install" and "make test" still
768            tried to test it.
770        (b) There were problems when the value of CXX was explicitly set. Some
771            changes have been made to try to fix these, and ...
773        (c) --disable-cpp can now be used to explicitly disable C++ support.
775        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
776            backslash in a target when C++ was disabled. This confuses some
777            versions of "make", apparently. Using an intermediate variable solves
778            this. (Same for CPP_LOBJ.)
780     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
781        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
782        necessary on certain architectures.
784     4. Added a setting of -export-symbols-regex to the link command to remove
785        those symbols that are exported in the C sense, but actually are local
786        within the library, and not documented. Their names all begin with
787        "_pcre_". This is not a perfect job, because (a) we have to except some
788        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
789        available (and never for static libraries). I have made a note to try to
790        find a way round (a) in the future.
793    Version 6.2 01-Aug-05
794    ---------------------
796     1. There was no test for integer overflow of quantifier values. A construction
797        such as {1111111111111111} would give undefined results. What is worse, if
798        a minimum quantifier for a parenthesized subpattern overflowed and became
799        negative, the calculation of the memory size went wrong. This could have
800        led to memory overwriting.
802     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
804     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
805        operating environments where this matters.
807     4. Applied Giuseppe Maxia's patch to add additional features for controlling
808        PCRE options from within the C++ wrapper.
810     5. Named capturing subpatterns were not being correctly counted when a pattern
811        was compiled. This caused two problems: (a) If there were more than 100
812        such subpatterns, the calculation of the memory needed for the whole
813        compiled pattern went wrong, leading to an overflow error. (b) Numerical
814        back references of the form \12, where the number was greater than 9, were
815        not recognized as back references, even though there were sufficient
816        previous subpatterns.
818     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
819        versions of gcc, e.g. 2.95.4.
822    Version 6.1 21-Jun-05
823    ---------------------
825     1. There was one reference to the variable "posix" in pcretest.c that was not
826        surrounded by "#if !defined NOPOSIX".
828     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
829        the cross-check on the old pcre_info() function, for the benefit of the
830        cut-down version of PCRE that is currently imported into Exim.
832     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
833        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
834        patterns that start (?i) but I don't think that matters. The use of (?i) is
835        just an example; this all applies to the other options as well.
837     4. Since libtool seems to echo the compile commands it is issuing, the output
838        from "make" can be reduced a bit by putting "@" in front of each libtool
839        compile command.
841     5. Patch from the folks at Google for configure.in to be a bit more thorough
842        in checking for a suitable C++ installation before trying to compile the
843        C++ stuff. This should fix a reported problem when a compiler was present,
844        but no suitable headers.
846     6. The man pages all had just "PCRE" as their title. I have changed them to
847        be the relevant file name. I have also arranged that these names are
848        retained in the file doc/pcre.txt, which is a concatenation in text format
849        of all the man pages except the little individual ones for each function.
851     7. The NON-UNIX-USE file had not been updated for the different set of source
852        files that come with release 6. I also added a few comments about the C++
853        wrapper.
856    Version 6.0 07-Jun-05
857    ---------------------
859     1. Some minor internal re-organization to help with my DFA experiments.
861     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
862        didn't matter for the library itself when fully configured, but did matter
863        when compiling without UCP support, or within Exim, where the ucp files are
864        not imported.
866     3. Refactoring of the library code to split up the various functions into
867        different source modules. The addition of the new DFA matching code (see
868        below) to a single monolithic source would have made it really too
869        unwieldy, quite apart from causing all the code to be include in a
870        statically linked application, when only some functions are used. This is
871        relevant even without the DFA addition now that patterns can be compiled in
872        one application and matched in another.
874        The downside of splitting up is that there have to be some external
875        functions and data tables that are used internally in different modules of
876        the library but which are not part of the API. These have all had their
877        names changed to start with "_pcre_" so that they are unlikely to clash
878        with other external names.
880     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
881        a different (DFA) algorithm. Although it is slower than the original
882        function, it does have some advantages for certain types of matching
883        problem.
885     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
886        including restarting after a partial match.
888     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
889        defined when compiling for Windows was sent to me. I have put it into the
890        code, though I have no means of testing or verifying it.
892     7. Added the pcre_refcount() auxiliary function.
894     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
895        match before or at the first newline in the subject string. In pcretest,
896        the /f option on a pattern can be used to set this.
898     9. A repeated \w when used in UTF-8 mode with characters greater than 256
899        would behave wrongly. This has been present in PCRE since release 4.0.
901    10. A number of changes to the pcregrep command:
903        (a) Refactored how -x works; insert ^(...)$ instead of setting
904            PCRE_ANCHORED and checking the length, in preparation for adding
905            something similar for -w.
907        (b) Added the -w (match as a word) option.
909        (c) Refactored the way lines are read and buffered so as to have more
910            than one at a time available.
912        (d) Implemented a pcregrep test script.
914        (e) Added the -M (multiline match) option. This allows patterns to match
915            over several lines of the subject. The buffering ensures that at least
916            8K, or the rest of the document (whichever is the shorter) is available
917            for matching (and similarly the previous 8K for lookbehind assertions).
919        (f) Changed the --help output so that it now says
921              -w, --word-regex(p)
923            instead of two lines, one with "regex" and the other with "regexp"
924            because that confused at least one person since the short forms are the
925            same. (This required a bit of code, as the output is generated
926            automatically from a table. It wasn't just a text change.)
928        (g) -- can be used to terminate pcregrep options if the next thing isn't an
929            option but starts with a hyphen. Could be a pattern or a path name
930            starting with a hyphen, for instance.
932        (h) "-" can be given as a file name to represent stdin.
934        (i) When file names are being printed, "(standard input)" is used for
935            the standard input, for compatibility with GNU grep. Previously
936            "<stdin>" was used.
938        (j) The option --label=xxx can be used to supply a name to be used for
939            stdin when file names are being printed. There is no short form.
941        (k) Re-factored the options decoding logic because we are going to add
942            two more options that take data. Such options can now be given in four
943            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
945        (l) Added the -A, -B, and -C options for requesting that lines of context
946            around matches be printed.
948        (m) Added the -L option to print the names of files that do not contain
949            any matching lines, that is, the complement of -l.
951        (n) The return code is 2 if any file cannot be opened, but pcregrep does
952            continue to scan other files.
954        (o) The -s option was incorrectly implemented. For compatibility with other
955            greps, it now suppresses the error message for a non-existent or non-
956            accessible file (but not the return code). There is a new option called
957            -q that suppresses the output of matching lines, which was what -s was
958            previously doing.
960        (p) Added --include and --exclude options to specify files for inclusion
961            and exclusion when recursing.
963    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
964        Hopefully, it now does.
966    12. Missing cast in pcre_study().
968    13. Added an "uninstall" target to the makefile.
970    14. Replaced "extern" in the function prototypes in Makefile.in with
971        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
972        world, but is set differently for Windows.
974    15. Added a second compiling function called pcre_compile2(). The only
975        difference is that it has an extra argument, which is a pointer to an
976        integer error code. When there is a compile-time failure, this is set
977        non-zero, in addition to the error test pointer being set to point to an
978        error message. The new argument may be NULL if no error number is required
979        (but then you may as well call pcre_compile(), which is now just a
980        wrapper). This facility is provided because some applications need a
981        numeric error indication, but it has also enabled me to tidy up the way
982        compile-time errors are handled in the POSIX wrapper.
984    16. Added VPATH=.libs to the makefile; this should help when building with one
985        prefix path and installing with another. (Or so I'm told by someone who
986        knows more about this stuff than I do.)
988    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
989        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
990        match everything, including newlines. This is not POSIX-compatible, but
991        somebody wanted the feature. From pcretest it can be activated by using
992        both the P and the s flags.
994    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
996    19. libpcre.pc was being incorrectly installed as executable.
998    20. A couple of places in pcretest check for end-of-line by looking for '\n';
999        it now also looks for '\r' so that it will work unmodified on Windows.
1001    21. Added Google's contributed C++ wrapper to the distribution.
1003    22. Added some untidy missing memory free() calls in pcretest, to keep
1004        Electric Fence happy when testing.
1008    Version 5.0 13-Sep-04
1009    ---------------------
1011     1. Internal change: literal characters are no longer packed up into items
1012        containing multiple characters in a single byte-string. Each character
1013        is now matched using a separate opcode. However, there may be more than one
1014        byte in the character in UTF-8 mode.
1016     2. The pcre_callout_block structure has two new fields: pattern_position and
1017        next_item_length. These contain the offset in the pattern to the next match
1018        item, and its length, respectively.
1020     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1021        insertion of callouts before each pattern item. Added the /C option to
1022        pcretest to make use of this.
1024     4. On the advice of a Windows user, the lines
1026          #if defined(_WIN32) || defined(WIN32)
1027          _setmode( _fileno( stdout ), 0x8000 );
1028          #endif  /* defined(_WIN32) || defined(WIN32) */
1030        have been added to the source of pcretest. This apparently does useful
1031        magic in relation to line terminators.
1033     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1034        for the benefit of those environments where the "b" makes a difference.
1036     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1037        to know about it. I have put a hack into configure.in that adds in code
1038        to set GCC=yes if CC=icc. This seems to end up at a point in the
1039        generated configure script that is early enough to affect the setting of
1040        compiler options, which is what is needed, but I have no means of testing
1041        whether it really works. (The user who reported this had patched the
1042        generated configure script, which of course I cannot do.)
1044        LATER: After change 22 below (new libtool files), the configure script
1045        seems to know about icc (and also ecc). Therefore, I have commented out
1046        this hack in configure.in.
1048     7. Added support for pkg-config (2 patches were sent in).
1050     8. Negated POSIX character classes that used a combination of internal tables
1051        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1052        [[:^ascii]]. Typically, they would match almost any characters. The other
1053        POSIX classes were not broken in this way.
1055     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1056        to find the match, as PCRE was deluded into thinking that the match had to
1057        start at the start point or following a newline. The same bug applied to
1058        patterns with negative forward assertions or any backward assertions
1059        preceding ".*" at the start, unless the pattern required a fixed first
1060        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1062    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1063        starting at the last subject character, bytes beyond the end of the subject
1064        string were read.
1066    11. Renamed the variable "class" as "classbits" to make life easier for C++
1067        users. (Previously there was a macro definition, but it apparently wasn't
1068        enough.)
1070    12. Added the new field "tables" to the extra data so that tables can be passed
1071        in at exec time, or the internal tables can be re-selected. This allows
1072        a compiled regex to be saved and re-used at a later time by a different
1073        program that might have everything at different addresses.
1075    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1076        -R library as well as a -L library.
1078    14. The debugging options of pcretest (-d on the command line or D on a
1079        pattern) showed incorrect output for anything following an extended class
1080        that contained multibyte characters and which was followed by a quantifier.
1082    15. Added optional support for general category Unicode character properties
1083        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1084        support. It adds about 90K to the size of the library. The meanings of the
1085        inbuilt class escapes such as \d and \s have NOT been changed.
1087    16. Updated pcredemo.c to include calls to free() to release the memory for the
1088        compiled pattern.
1090    17. The generated file chartables.c was being created in the source directory
1091        instead of in the building directory. This caused the build to fail if the
1092        source directory was different from the building directory, and was
1093        read-only.
1095    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1096        file. No doubt somebody will tell me if they don't make sense... Also added
1097        Dan Mooney's comments about building on OpenVMS.
1099    19. Added support for partial matching via the PCRE_PARTIAL option for
1100        pcre_exec() and the \P data escape in pcretest.
1102    20. Extended pcretest with 3 new pattern features:
1104        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1105              write the compiled pattern to the file whose name is "rest-of-line".
1106              This is a straight binary dump of the data, with the saved pointer to
1107              the character tables forced to be NULL. The study data, if any, is
1108              written too. After writing, pcretest reads a new pattern.
1110        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1111              compiled pattern from the given file. There must not be any
1112              occurrences of "<" in the file name (pretty unlikely); if there are,
1113              pcretest will instead treat the initial "<" as a pattern delimiter.
1114              After reading in the pattern, pcretest goes on to read data lines as
1115              usual.
1117        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1118              and 16-bit fields in a compiled pattern, to simulate a pattern that
1119              was compiled on a host of opposite endianness.
1121    21. The pcre-exec() function can now cope with patterns that were compiled on
1122        hosts of opposite endianness, with this restriction:
1124          As for any compiled expression that is saved and used later, the tables
1125          pointer field cannot be preserved; the extra_data field in the arguments
1126          to pcre_exec() should be used to pass in a tables address if a value
1127          other than the default internal tables were used at compile time.
1129    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1130        now diagnosed as an error. Previously, most of the time, a negative number
1131        would have been treated as zero, but if in addition "ovector" was passed as
1132        NULL, a crash could occur.
1134    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1135        new versions from the libtool 1.5 distribution (the last one is a copy of
1136        a file called libtool.m4). This seems to have fixed the need to patch
1137        "configure" to support Darwin 1.3 (which I used to do). However, I still
1138        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1139        workstation).
1141    24. Changed the PCRE licence to be the more standard "BSD" licence.
1144    Version 4.5 01-Dec-03
1145    ---------------------
1147     1. There has been some re-arrangement of the code for the match() function so
1148        that it can be compiled in a version that does not call itself recursively.
1149        Instead, it keeps those local variables that need separate instances for
1150        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1151        needs to "recurse". Keeping track of where control must go is done by means
1152        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1153        hide most of the details from the main code, and operates only if
1154        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1155        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1156        operating.
1158        To make it easier for callers to provide specially tailored get/free
1159        functions for this usage, two new functions, pcre_stack_malloc, and
1160        pcre_stack_free, are used. They are always called in strict stacking order,
1161        and the size of block requested is always the same.
1163        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1164        PCRE has been compiled to use the stack or the heap for recursion. The
1165        -C option of pcretest uses this to show which version is compiled.
1167        A new data escape \S, is added to pcretest; it causes the amounts of store
1168        obtained and freed by both kinds of malloc/free at match time to be added
1169        to the output.
1171     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1172        what's available on my current Linux desktop machine.
1174     3. When matching a UTF-8 string, the test for a valid string at the start has
1175        been extended. If start_offset is not zero, PCRE now checks that it points
1176        to a byte that is the start of a UTF-8 character. If not, it returns
1177        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1178        this is necessary because there may be backward assertions in the pattern.
1179        When matching the same subject several times, it may save resources to use
1180        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1182     4. The code for checking the validity of UTF-8 strings has been tightened so
1183        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1184        containing "overlong sequences".
1186     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1187        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1188        should have been "&", but it just so happened that all the cases this let
1189        through by mistake were picked up later in the function.
1191     6. I had used a variable called "isblank" - this is a C99 function, causing
1192        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1194     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1195        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1196        so the version is shown; (c) stop "make test" echoing "./RunTest".
1198     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1200     9. The prototype for memmove() for systems that don't have it was using
1201        size_t, but the inclusion of the header that defines size_t was later. I've
1202        moved the #includes for the C headers earlier to avoid this.
1204    10. Added some adjustments to the code to make it easier to compiler on certain
1205        special systems:
1207          (a) Some "const" qualifiers were missing.
1208          (b) Added the macro EXPORT before all exported functions; by default this
1209              is defined to be empty.
1210          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1211              that it reads its output file name as an argument instead of writing
1212              to the standard output and assuming this can be redirected.
1214    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1215        class containing characters with values greater than 255, PCRE compilation
1216        went into a loop.
1218    12. A recursive reference to a subpattern that was within another subpattern
1219        that had a minimum quantifier of zero caused PCRE to crash. For example,
1220        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1221        recursion. If the recursively-called subpattern itself had a zero repeat,
1222        that was OK.
1224    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1225        buffer into which it was copied (for escape processing) was still set at
1226        1024, so long lines caused crashes.
1228    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1229        "internal error: code overflow...". This applied to any character class
1230        that was followed by a possessive quantifier.
1232    15. Modified the Makefile to add libpcre.la as a prerequisite for
1233        libpcreposix.la because I was told this is needed for a parallel build to
1234        work.
1236    16. If a pattern that contained .* following optional items at the start was
1237        studied, the wrong optimizing data was generated, leading to matching
1238        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1239        matching string must start with a or b or c. The correct conclusion for
1240        this pattern is that a match can start with any character.
1243    Version 4.4 13-Aug-03
1244    ---------------------
1246     1. In UTF-8 mode, a character class containing characters with values between
1247        127 and 255 was not handled correctly if the compiled pattern was studied.
1248        In fixing this, I have also improved the studying algorithm for such
1249        classes (slightly).
1251     2. Three internal functions had redundant arguments passed to them. Removal
1252        might give a very teeny performance improvement.
1254     3. Documentation bug: the value of the capture_top field in a callout is *one
1255        more than* the number of the hightest numbered captured substring.
1257     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1258        in incorrectly linking with a previously installed version. They now link
1259        explicitly with libpcre.la.
1261     5. configure.in no longer needs to recognize Cygwin specially.
1263     6. A problem in pcre.in for Windows platforms is fixed.
1265     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1266        pcretest, it used to include the size of the study block as part of its
1267        output. Unfortunately, the structure contains a field that has a different
1268        size on different hardware architectures. This meant that the tests that
1269        showed this size failed. As the block is currently always of a fixed size,
1270        this information isn't actually particularly useful in pcretest output, so
1271        I have just removed it.
1273     8. Three pre-processor statements accidentally did not start in column 1.
1274        Sadly, there are *still* compilers around that complain, even though
1275        standard C has not required this for well over a decade. Sigh.
1277     9. In pcretest, the code for checking callouts passed small integers in the
1278        callout_data field, which is a void * field. However, some picky compilers
1279        complained about the casts involved for this on 64-bit systems. Now
1280        pcretest passes the address of the small integer instead, which should get
1281        rid of the warnings.
1283    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1284        both compile and run time, and gives an error if an invalid UTF-8 sequence
1285        is found. There is a option for disabling this check in cases where the
1286        string is known to be correct and/or the maximum performance is wanted.
1288    11. In response to a bug report, I changed one line in Makefile.in from
1290            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1291        to
1292            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1294        to look similar to other lines, but I have no way of telling whether this
1295        is the right thing to do, as I do not use Windows. No doubt I'll get told
1296        if it's wrong...
1299  Version 4.3 21-May-03  Version 4.3 21-May-03
1300  ---------------------  ---------------------

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