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revision 47 by nigel, Sat Feb 24 21:39:29 2007 UTC revision 222 by ph10, Fri Aug 17 10:48:51 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 17-Aug-07
5    ---------------------
6    
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
12    
13          #include "pcre.h"
14    
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
18    
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
26    
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
28    
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
31    
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
34    
35     6. ESC_K was left out of the EBCDIC table.
36    
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
50    
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
55    
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
67    
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
72    
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
79    
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
86    
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
90    
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
93    
94    14. Optimized (?!) to (*FAIL).
95    
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
101    
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
105    
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
108    
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
111    
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
116    
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
119    
120    21. An orphan \E inside a character class could cause a crash.
121    
122    22. A repeated capturing bracket such as (A)? could cause a wild memory
123        reference during compilation.
124    
125    23. There are several functions in pcre_compile() that scan along a compiled
126        expression for various reasons (e.g. to see if it's fixed length for look
127        behind). There were bugs in these functions when a repeated \p or \P was
128        present in the pattern. These operators have additional parameters compared
129        with \d, etc, and these were not being taken into account when moving along
130        the compiled data. Specifically:
131    
132        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
133            length.
134    
135        (b) An item such as \pL+ within a repeated group could cause crashes or
136            loops.
137    
138        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
139            "reference to non-existent subpattern" error.
140    
141        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
142    
143    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
144        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
145    
146    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
147    
148    
149    Version 7.2 19-Jun-07
150    ---------------------
151    
152     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
153        which is apparently normally available under Windows.
154    
155     2. Re-jig the pcregrep tests with different newline settings in an attempt
156        to make them independent of the local environment's newline setting.
157    
158     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
159    
160     4. Some of the "internals" tests were previously cut out when the link size
161        was not 2, because the output contained actual offsets. The recent new
162        "Z" feature of pcretest means that these can be cut out, making the tests
163        usable with all link sizes.
164    
165     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
166        stack recursion. This gives a massive performance boost under BSD, but just
167        a small improvement under Linux. However, it saves one field in the frame
168        in all cases.
169    
170     6. Added more features from the forthcoming Perl 5.10:
171    
172        (a) (?-n) (where n is a string of digits) is a relative subroutine or
173            recursion call. It refers to the nth most recently opened parentheses.
174    
175        (b) (?+n) is also a relative subroutine call; it refers to the nth next
176            to be opened parentheses.
177    
178        (c) Conditions that refer to capturing parentheses can be specified
179            relatively, for example, (?(-2)... or (?(+3)...
180    
181        (d) \K resets the start of the current match so that everything before
182            is not part of it.
183    
184        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
185    
186        (f) \g{name} is another synonym - part of Perl 5.10's unification of
187            reference syntax.
188    
189        (g) (?| introduces a group in which the numbering of parentheses in each
190            alternative starts with the same number.
191    
192        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
193    
194     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
195        PCRE_INFO_JCHANGED.
196    
197     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
198        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
199        for detecting groups that can match an empty string.
200    
201     9. A pattern with a very large number of alternatives (more than several
202        hundred) was running out of internal workspace during the pre-compile
203        phase, where pcre_compile() figures out how much memory will be needed. A
204        bit of new cunning has reduced the workspace needed for groups with
205        alternatives. The 1000-alternative test pattern now uses 12 bytes of
206        workspace instead of running out of the 4096 that are available.
207    
208    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
209    
210    11. Applied patch from Google to remove an optimization that didn't quite work.
211        The report of the bug said:
212    
213          pcrecpp::RE("a*").FullMatch("aaa") matches, while
214          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
215          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
216    
217    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
218        it matched the wrong number of bytes.
219    
220    
221    Version 7.1 24-Apr-07
222    ---------------------
223    
224     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
225        that is more "standard", making use of automake and other Autotools. There
226        is some re-arrangement of the files and adjustment of comments consequent
227        on this.
228    
229     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
230        for recursive directory scanning broke on some systems because the files
231        are not scanned in any specific order and on different systems the order
232        was different. A call to "sort" has been inserted into RunGrepTest for the
233        approprate test as a short-term fix. In the longer term there may be an
234        alternative.
235    
236     3. I had an email from Eric Raymond about problems translating some of PCRE's
237        man pages to HTML (despite the fact that I distribute HTML pages, some
238        people do their own conversions for various reasons). The problems
239        concerned the use of low-level troff macros .br and .in. I have therefore
240        removed all such uses from the man pages (some were redundant, some could
241        be replaced by .nf/.fi pairs). The 132html script that I use to generate
242        HTML has been updated to handle .nf/.fi and to complain if it encounters
243        .br or .in.
244    
245     4. Updated comments in configure.ac that get placed in config.h.in and also
246        arranged for config.h to be included in the distribution, with the name
247        config.h.generic, for the benefit of those who have to compile without
248        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
249    
250     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
251        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
252        makevp.bat for the current PCRE, using the additional files
253        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
254    
255     6. A Windows user reported a minor discrepancy with test 2, which turned out
256        to be caused by a trailing space on an input line that had got lost in his
257        copy. The trailing space was an accident, so I've just removed it.
258    
259     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
260        that is needed.
261    
262     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
263        as "const" (a) because they are and (b) because it helps the PHP
264        maintainers who have recently made a script to detect big data structures
265        in the php code that should be moved to the .rodata section. I remembered
266        to update Builducptable as well, so it won't revert if ucptable.h is ever
267        re-created.
268    
269     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
270        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
271        order to be able to cut out the UTF-8 tables in the latter when UTF-8
272        support is not required. This saves 1.5-2K of code, which is important in
273        some applications.
274    
275        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
276        so as not to refer to the tables, even though these functions will never be
277        called when UTF-8 support is disabled. Otherwise there are problems with a
278        shared library.
279    
280    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
281    
282        (a) It was defining its arguments as char * instead of void *.
283    
284        (b) It was assuming that all moves were upwards in memory; this was true
285            a long time ago when I wrote it, but is no longer the case.
286    
287        The emulated memove() is provided for those environments that have neither
288        memmove() nor bcopy(). I didn't think anyone used it these days, but that
289        is clearly not the case, as these two bugs were recently reported.
290    
291    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
292        and Detrail to create the HTML documentation, the .txt form of the man
293        pages, and it removes trailing spaces from listed files. It also creates
294        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
295        case, it wraps all the #defines with #ifndefs. This script should be run
296        before "make dist".
297    
298    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
299        with Unicode property support.
300    
301        (a) For a maximizing quantifier, if the two different cases of the
302            character were of different lengths in their UTF-8 codings (there are
303            some cases like this - I found 11), and the matching function had to
304            back up over a mixture of the two cases, it incorrectly assumed they
305            were both the same length.
306    
307        (b) When PCRE was configured to use the heap rather than the stack for
308            recursion during matching, it was not correctly preserving the data for
309            the other case of a UTF-8 character when checking ahead for a match
310            while processing a minimizing repeat. If the check also involved
311            matching a wide character, but failed, corruption could cause an
312            erroneous result when trying to check for a repeat of the original
313            character.
314    
315    13. Some tidying changes to the testing mechanism:
316    
317        (a) The RunTest script now detects the internal link size and whether there
318            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
319            values substituted by "configure". (The RunGrepTest script already did
320            this for UTF-8.) The configure.ac script no longer substitutes the
321            relevant variables.
322    
323        (b) The debugging options /B and /D in pcretest show the compiled bytecode
324            with length and offset values. This means that the output is different
325            for different internal link sizes. Test 2 is skipped for link sizes
326            other than 2 because of this, bypassing the problem. Unfortunately,
327            there was also a test in test 3 (the locale tests) that used /B and
328            failed for link sizes other than 2. Rather than cut the whole test out,
329            I have added a new /Z option to pcretest that replaces the length and
330            offset values with spaces. This is now used to make test 3 independent
331            of link size. (Test 2 will be tidied up later.)
332    
333    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
334        segmentation fault instead of returning the appropriate error message.
335    
336    15. In multiline mode when the newline sequence was set to "any", the pattern
337        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
338        This doesn't seem right; it now treats the CRLF combination as the line
339        ending, and so does not match in that case. It's only a pattern such as ^$
340        that would hit this one: something like ^ABC$ would have failed after \r
341        and then tried again after \r\n.
342    
343    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
344        in an attempt to make files that differ only in their line terminators
345        compare equal. This works on Linux.
346    
347    17. Under certain error circumstances pcregrep might try to free random memory
348        as it exited. This is now fixed, thanks to valgrind.
349    
350    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
351        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
352        was because its rules for how to advance for /g after matching an empty
353        string at the end of a line did not allow for this case. They now check for
354        it specially.
355    
356    20. pcretest is supposed to handle patterns and data of any length, by
357        extending its buffers when necessary. It was getting this wrong when the
358        buffer for a data line had to be extended.
359    
360    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
361        CRLF as a newline sequence.
362    
363    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
364        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
365        I have nevertheless tidied it up.
366    
367    23. Added some casts to kill warnings from HP-UX ia64 compiler.
368    
369    24. Added a man page for pcre-config.
370    
371    
372    Version 7.0 19-Dec-06
373    ---------------------
374    
375     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
376        moving to gcc 4.1.1.
377    
378     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
379        sys/time.h, which is documented as needed for this function. It doesn't
380        seem to matter on Linux, but it showed up on some releases of OS X.
381    
382     3. It seems that there are systems where bytes whose values are greater than
383        127 match isprint() in the "C" locale. The "C" locale should be the
384        default when a C program starts up. In most systems, only ASCII printing
385        characters match isprint(). This difference caused the output from pcretest
386        to vary, making some of the tests fail. I have changed pcretest so that:
387    
388        (a) When it is outputting text in the compiled version of a pattern, bytes
389            other than 32-126 are always shown as hex escapes.
390    
391        (b) When it is outputting text that is a matched part of a subject string,
392            it does the same, unless a different locale has been set for the match
393            (using the /L modifier). In this case, it uses isprint() to decide.
394    
395     4. Fixed a major bug that caused incorrect computation of the amount of memory
396        required for a compiled pattern when options that changed within the
397        pattern affected the logic of the preliminary scan that determines the
398        length. The relevant options are -x, and -i in UTF-8 mode. The result was
399        that the computed length was too small. The symptoms of this bug were
400        either the PCRE error "internal error: code overflow" from pcre_compile(),
401        or a glibc crash with a message such as "pcretest: free(): invalid next
402        size (fast)". Examples of patterns that provoked this bug (shown in
403        pcretest format) are:
404    
405          /(?-x: )/x
406          /(?x)(?-x: \s*#\s*)/
407          /((?i)[\x{c0}])/8
408          /(?i:[\x{c0}])/8
409    
410        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
411        is now done differently.
412    
413     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
414        wrapper classes; (b) implement a new function in the C++ scanner that is
415        more efficient than the old way of doing things because it avoids levels of
416        recursion in the regex matching; (c) add a paragraph to the documentation
417        for the FullMatch() function.
418    
419     6. The escape sequence \n was being treated as whatever was defined as
420        "newline". Not only was this contrary to the documentation, which states
421        that \n is character 10 (hex 0A), but it also went horribly wrong when
422        "newline" was defined as CRLF. This has been fixed.
423    
424     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
425        was being set to -1 for the "end of line" case (supposedly a value that no
426        character can have). Though this value is never used (the check for end of
427        line is "zero bytes in current character"), it caused compiler complaints.
428        I've changed it to 0xffffffff.
429    
430     8. In pcre_version.c, the version string was being built by a sequence of
431        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
432        string (as it is for production releases) called a macro with an empty
433        argument. The C standard says the result of this is undefined. The gcc
434        compiler treats it as an empty string (which was what was wanted) but it is
435        reported that Visual C gives an error. The source has been hacked around to
436        avoid this problem.
437    
438     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
439        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
440        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
441        of them did).
442    
443    10. Originally, pcretest opened its input and output without "b"; then I was
444        told that "b" was needed in some environments, so it was added for release
445        5.0 to both the input and output. (It makes no difference on Unix-like
446        systems.) Later I was told that it is wrong for the input on Windows. I've
447        now abstracted the modes into two macros, to make it easier to fiddle with
448        them, and removed "b" from the input mode under Windows.
449    
450    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
451    
452    12. Added -help and --help to pcretest as an official way of being reminded
453        of the options.
454    
455    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
456        and pcrecpp.cc because they annoy compilers at high warning levels.
457    
458    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
459    
460    15. Fixed an occurrence of == in configure.ac that should have been = (shell
461        scripts are not C programs :-) and which was not noticed because it works
462        on Linux.
463    
464    16. pcretest is supposed to handle any length of pattern and data line (as one
465        line or as a continued sequence of lines) by extending its input buffer if
466        necessary. This feature was broken for very long pattern lines, leading to
467        a string of junk being passed to pcre_compile() if the pattern was longer
468        than about 50K.
469    
470    17. I have done a major re-factoring of the way pcre_compile() computes the
471        amount of memory needed for a compiled pattern. Previously, there was code
472        that made a preliminary scan of the pattern in order to do this. That was
473        OK when PCRE was new, but as the facilities have expanded, it has become
474        harder and harder to keep it in step with the real compile phase, and there
475        have been a number of bugs (see for example, 4 above). I have now found a
476        cunning way of running the real compile function in a "fake" mode that
477        enables it to compute how much memory it would need, while actually only
478        ever using a few hundred bytes of working memory and without too many
479        tests of the mode. This should make future maintenance and development
480        easier. A side effect of this work is that the limit of 200 on the nesting
481        depth of parentheses has been removed (though this was never a serious
482        limitation, I suspect). However, there is a downside: pcre_compile() now
483        runs more slowly than before (30% or more, depending on the pattern). I
484        hope this isn't a big issue. There is no effect on runtime performance.
485    
486    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
487        newline (only possible for the last line of a file) and it was a
488        pattern that set a locale (followed by /Lsomething), pcretest crashed.
489    
490    19. Added additional timing features to pcretest. (1) The -tm option now times
491        matching only, not compiling. (2) Both -t and -tm can be followed, as a
492        separate command line item, by a number that specifies the number of
493        repeats to use when timing. The default is 50000; this gives better
494        precision, but takes uncomfortably long for very large patterns.
495    
496    20. Extended pcre_study() to be more clever in cases where a branch of a
497        subpattern has no definite first character. For example, (a*|b*)[cd] would
498        previously give no result from pcre_study(). Now it recognizes that the
499        first character must be a, b, c, or d.
500    
501    21. There was an incorrect error "recursive call could loop indefinitely" if
502        a subpattern (or the entire pattern) that was being tested for matching an
503        empty string contained only one non-empty item after a nested subpattern.
504        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
505        incorrectly, because the \d was being skipped in the check.
506    
507    22. The pcretest program now has a new pattern option /B and a command line
508        option -b, which is equivalent to adding /B to every pattern. This causes
509        it to show the compiled bytecode, without the additional information that
510        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
511        is the same as /B/I).
512    
513    23. A new optimization is now able automatically to treat some sequences such
514        as a*b as a*+b. More specifically, if something simple (such as a character
515        or a simple class like \d) has an unlimited quantifier, and is followed by
516        something that cannot possibly match the quantified thing, the quantifier
517        is automatically "possessified".
518    
519    24. A recursive reference to a subpattern whose number was greater than 39
520        went wrong under certain circumstances in UTF-8 mode. This bug could also
521        have affected the operation of pcre_study().
522    
523    25. Realized that a little bit of performance could be had by replacing
524        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
525    
526    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
527    
528    27. Possessive quantifiers such as a++ were previously implemented by turning
529        them into atomic groups such as ($>a+). Now they have their own opcodes,
530        which improves performance. This includes the automatically created ones
531        from 23 above.
532    
533    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
534        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
535        the first matched character to be a colon. This applied both to named and
536        numbered groups.
537    
538    29. The ucpinternal.h header file was missing its idempotency #ifdef.
539    
540    30. I was sent a "project" file called libpcre.a.dev which I understand makes
541        building PCRE on Windows easier, so I have included it in the distribution.
542    
543    31. There is now a check in pcretest against a ridiculously large number being
544        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
545        loop, the loop is abandoned.
546    
547    32. Forward references to subpatterns in conditions such as (?(2)...) where
548        subpattern 2 is defined later cause pcre_compile() to search forwards in
549        the pattern for the relevant set of parentheses. This search went wrong
550        when there were unescaped parentheses in a character class, parentheses
551        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
552    
553    33. "Subroutine" calls and backreferences were previously restricted to
554        referencing subpatterns earlier in the regex. This restriction has now
555        been removed.
556    
557    34. Added a number of extra features that are going to be in Perl 5.10. On the
558        whole, these are just syntactic alternatives for features that PCRE had
559        previously implemented using the Python syntax or my own invention. The
560        other formats are all retained for compatibility.
561    
562        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
563            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
564            also .NET compatible.
565    
566        (b) A recursion or subroutine call to a named group can now be defined as
567            (?&name) as well as (?P>name).
568    
569        (c) A backreference to a named group can now be defined as \k<name> or
570            \k'name' as well as (?P=name). The new forms, as well as being in Perl
571            5.10, are also .NET compatible.
572    
573        (d) A conditional reference to a named group can now use the syntax
574            (?(<name>) or (?('name') as well as (?(name).
575    
576        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
577            groups (named and numbered) that are never evaluated inline, but can be
578            called as "subroutines" from elsewhere. In effect, the DEFINE condition
579            is always false. There may be only one alternative in such a group.
580    
581        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
582            as the simple (?(R). The condition is true only if the most recent
583            recursion is that of the given number or name. It does not search out
584            through the entire recursion stack.
585    
586        (g) The escape \gN or \g{N} has been added, where N is a positive or
587            negative number, specifying an absolute or relative reference.
588    
589    35. Tidied to get rid of some further signed/unsigned compiler warnings and
590        some "unreachable code" warnings.
591    
592    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
593        things, this adds five new scripts.
594    
595    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
596        There were also incompatibilities regarding the handling of \Q..\E inside
597        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
598        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
599    
600    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
601        matches an empty string, and forcibly breaks the loop. There were bugs in
602        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
603        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
604        separate and independent bugs (that affected different cases) have been
605        fixed.
606    
607    39. Refactored the code to abolish the use of different opcodes for small
608        capturing bracket numbers. This is a tidy that I avoided doing when I
609        removed the limit on the number of capturing brackets for 3.5 back in 2001.
610        The new approach is not only tidier, it makes it possible to reduce the
611        memory needed to fix the previous bug (38).
612    
613    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
614        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
615        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
616        mode.
617    
618    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
619        report.
620    
621    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
622        copy construction and assignment in the C++ wrapper.
623    
624    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
625        couple of bugs that could have given wrong results in the "--newline=crlf"
626        case.
627    
628    44. Added a number of casts and did some reorganization of signed/unsigned int
629        variables following suggestions from Dair Grant. Also renamed the variable
630        "this" as "item" because it is a C++ keyword.
631    
632    45. Arranged for dftables to add
633    
634          #include "pcre_internal.h"
635    
636        to pcre_chartables.c because without it, gcc 4.x may remove the array
637        definition from the final binary if PCRE is built into a static library and
638        dead code stripping is activated.
639    
640    46. For an unanchored pattern, if a match attempt fails at the start of a
641        newline sequence, and the newline setting is CRLF or ANY, and the next two
642        characters are CRLF, advance by two characters instead of one.
643    
644    
645    Version 6.7 04-Jul-06
646    ---------------------
647    
648     1. In order to handle tests when input lines are enormously long, pcretest has
649        been re-factored so that it automatically extends its buffers when
650        necessary. The code is crude, but this _is_ just a test program. The
651        default size has been increased from 32K to 50K.
652    
653     2. The code in pcre_study() was using the value of the re argument before
654        testing it for NULL. (Of course, in any sensible call of the function, it
655        won't be NULL.)
656    
657     3. The memmove() emulation function in pcre_internal.h, which is used on
658        systems that lack both memmove() and bcopy() - that is, hardly ever -
659        was missing a "static" storage class specifier.
660    
661     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
662        containing an extended class (one that cannot be represented by a bitmap
663        because it contains high-valued characters or Unicode property items, e.g.
664        [\pZ]). Almost always one would set UTF-8 mode when processing such a
665        pattern, but PCRE should not loop if you do not (it no longer does).
666        [Detail: two cases were found: (a) a repeated subpattern containing an
667        extended class; (b) a recursive reference to a subpattern that followed a
668        previous extended class. It wasn't skipping over the extended class
669        correctly when UTF-8 mode was not set.]
670    
671     5. A negated single-character class was not being recognized as fixed-length
672        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
673        compile error "lookbehind assertion is not fixed length".
674    
675     6. The RunPerlTest auxiliary script was showing an unexpected difference
676        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
677        write a Perl script that can interpret lines of an input file either as
678        byte characters or as UTF-8, which is what "perltest" was being required to
679        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
680        can't do is switch easily at run time between having the "use utf8;" pragma
681        or not. In the end, I fudged it by using the RunPerlTest script to insert
682        "use utf8;" explicitly for the UTF-8 tests.
683    
684     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
685        the end of the subject string, contrary to the documentation and to what
686        Perl does. This was true of both matching functions. Now it matches only at
687        the start of the subject and immediately after *internal* newlines.
688    
689     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
690        a pointer to an int instead of a pointer to an unsigned long int. This
691        caused problems on 64-bit systems.
692    
693     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
694        instance of the 'standard' template library not being so standard".
695    
696    10. There was no check on the number of named subpatterns nor the maximum
697        length of a subpattern name. The product of these values is used to compute
698        the size of the memory block for a compiled pattern. By supplying a very
699        long subpattern name and a large number of named subpatterns, the size
700        computation could be caused to overflow. This is now prevented by limiting
701        the length of names to 32 characters, and the number of named subpatterns
702        to 10,000.
703    
704    11. Subpatterns that are repeated with specific counts have to be replicated in
705        the compiled pattern. The size of memory for this was computed from the
706        length of the subpattern and the repeat count. The latter is limited to
707        65535, but there was no limit on the former, meaning that integer overflow
708        could in principle occur. The compiled length of a repeated subpattern is
709        now limited to 30,000 bytes in order to prevent this.
710    
711    12. Added the optional facility to have named substrings with the same name.
712    
713    13. Added the ability to use a named substring as a condition, using the
714        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
715        are numbers (not recommended). Forward references are permitted.
716    
717    14. Added forward references in named backreferences (if you see what I mean).
718    
719    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
720        pattern could run off the end of the subject. For example, the pattern
721        "(?s)(.{1,5})"8 did this with the subject "ab".
722    
723    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
724        PCRE_CASELESS was set when matching characters that were quantified with ?
725        or *.
726    
727    17. A character class other than a single negated character that had a minimum
728        but no maximum quantifier - for example [ab]{6,} - was not handled
729        correctly by pce_dfa_exec(). It would match only one character.
730    
731    18. A valid (though odd) pattern that looked like a POSIX character
732        class but used an invalid character after [ (for example [[,abc,]]) caused
733        pcre_compile() to give the error "Failed: internal error: code overflow" or
734        in some cases to crash with a glibc free() error. This could even happen if
735        the pattern terminated after [[ but there just happened to be a sequence of
736        letters, a binary zero, and a closing ] in the memory that followed.
737    
738    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
739        over the years. Originally (before any Unicode support), just the bottom 8
740        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
741        output from "man perlunicode" includes this:
742    
743          The regular expression compiler produces polymorphic opcodes.  That
744          is, the pattern adapts to the data and automatically switches to
745          the Unicode character scheme when presented with Unicode data--or
746          instead uses a traditional byte scheme when presented with byte
747          data.
748    
749        Sadly, a wide octal escape does not cause a switch, and in a string with
750        no other multibyte characters, these octal escapes are treated as before.
751        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
752        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
753        Unicode string.
754    
755        I have not perpetrated such confusion in PCRE. Up till now, it took just
756        the bottom 8 bits, as in old Perl. I have now made octal escapes with
757        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
758        translate to the appropriate multibyte character.
759    
760    29. Applied some refactoring to reduce the number of warnings from Microsoft
761        and Borland compilers. This has included removing the fudge introduced
762        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
763        a warning about an unused variable.
764    
765    21. PCRE has not included VT (character 0x0b) in the set of whitespace
766        characters since release 4.0, because Perl (from release 5.004) does not.
767        [Or at least, is documented not to: some releases seem to be in conflict
768        with the documentation.] However, when a pattern was studied with
769        pcre_study() and all its branches started with \s, PCRE still included VT
770        as a possible starting character. Of course, this did no harm; it just
771        caused an unnecessary match attempt.
772    
773    22. Removed a now-redundant internal flag bit that recorded the fact that case
774        dependency changed within the pattern. This was once needed for "required
775        byte" processing, but is no longer used. This recovers a now-scarce options
776        bit. Also moved the least significant internal flag bit to the most-
777        significant bit of the word, which was not previously used (hangover from
778        the days when it was an int rather than a uint) to free up another bit for
779        the future.
780    
781    23. Added support for CRLF line endings as well as CR and LF. As well as the
782        default being selectable at build time, it can now be changed at runtime
783        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
784        specify that it is scanning data with non-default line endings.
785    
786    24. Changed the definition of CXXLINK to make it agree with the definition of
787        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
788    
789    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
790        recursions. This makes a big different to stack usage for some patterns.
791    
792    26. If a subpattern containing a named recursion or subroutine reference such
793        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
794        the space required for the compiled pattern went wrong and gave too small a
795        value. Depending on the environment, this could lead to "Failed: internal
796        error: code overflow at offset 49" or "glibc detected double free or
797        corruption" errors.
798    
799    27. Applied patches from Google (a) to support the new newline modes and (b) to
800        advance over multibyte UTF-8 characters in GlobalReplace.
801    
802    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
803        difference for some implementation of PCRE in some Windows version.
804    
805    29. Added some extra testing facilities to pcretest:
806    
807        \q<number>   in a data line sets the "match limit" value
808        \Q<number>   in a data line sets the "match recursion limt" value
809        -S <number>  sets the stack size, where <number> is in megabytes
810    
811        The -S option isn't available for Windows.
812    
813    
814    Version 6.6 06-Feb-06
815    ---------------------
816    
817     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
818        in pcreposix.h. I have copied the definition from pcre.h.
819    
820     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
821        because pcre.h is no longer a built file.
822    
823     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
824        not normally included in the compiled code.
825    
826    
827    Version 6.5 01-Feb-06
828    ---------------------
829    
830     1. When using the partial match feature with pcre_dfa_exec(), it was not
831        anchoring the second and subsequent partial matches at the new starting
832        point. This could lead to incorrect results. For example, with the pattern
833        /1234/, partially matching against "123" and then "a4" gave a match.
834    
835     2. Changes to pcregrep:
836    
837        (a) All non-match returns from pcre_exec() were being treated as failures
838            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
839            error message is output. Some extra information is given for the
840            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
841            probably the only errors that are likely to be caused by users (by
842            specifying a regex that has nested indefinite repeats, for instance).
843            If there are more than 20 of these errors, pcregrep is abandoned.
844    
845        (b) A binary zero was treated as data while matching, but terminated the
846            output line if it was written out. This has been fixed: binary zeroes
847            are now no different to any other data bytes.
848    
849        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
850            used to set a locale for matching. The --locale=xxxx long option has
851            been added (no short equivalent) to specify a locale explicitly on the
852            pcregrep command, overriding the environment variables.
853    
854        (d) When -B was used with -n, some line numbers in the output were one less
855            than they should have been.
856    
857        (e) Added the -o (--only-matching) option.
858    
859        (f) If -A or -C was used with -c (count only), some lines of context were
860            accidentally printed for the final match.
861    
862        (g) Added the -H (--with-filename) option.
863    
864        (h) The combination of options -rh failed to suppress file names for files
865            that were found from directory arguments.
866    
867        (i) Added the -D (--devices) and -d (--directories) options.
868    
869        (j) Added the -F (--fixed-strings) option.
870    
871        (k) Allow "-" to be used as a file name for -f as well as for a data file.
872    
873        (l) Added the --colo(u)r option.
874    
875        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
876            is not present by default.
877    
878     3. A nasty bug was discovered in the handling of recursive patterns, that is,
879        items such as (?R) or (?1), when the recursion could match a number of
880        alternatives. If it matched one of the alternatives, but subsequently,
881        outside the recursion, there was a failure, the code tried to back up into
882        the recursion. However, because of the way PCRE is implemented, this is not
883        possible, and the result was an incorrect result from the match.
884    
885        In order to prevent this happening, the specification of recursion has
886        been changed so that all such subpatterns are automatically treated as
887        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
888    
889     4. I had overlooked the fact that, in some locales, there are characters for
890        which isalpha() is true but neither isupper() nor islower() are true. In
891        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
892        and ordfeminine) are like this. This affected the treatment of \w and \W
893        when they appeared in character classes, but not when they appeared outside
894        a character class. The bit map for "word" characters is now created
895        separately from the results of isalnum() instead of just taking it from the
896        upper, lower, and digit maps. (Plus the underscore character, of course.)
897    
898     5. The above bug also affected the handling of POSIX character classes such as
899        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
900        permanent tables. Instead, the bit maps for such a class were previously
901        created as the appropriate unions of the upper, lower, and digit bitmaps.
902        Now they are created by subtraction from the [[:word:]] class, which has
903        its own bitmap.
904    
905     6. The [[:blank:]] character class matches horizontal, but not vertical space.
906        It is created by subtracting the vertical space characters (\x09, \x0a,
907        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
908        subtraction was done in the overall bitmap for a character class, meaning
909        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
910        be recognized. This bug has been fixed.
911    
912     7. Patches from the folks at Google:
913    
914          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
915          real life, but is still worth protecting against".
916    
917          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
918          regular expressions".
919    
920          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
921          have it.
922    
923          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
924          "configure" and the latter not, in order to fix a problem somebody had
925          with compiling the Arg class on HP-UX.
926    
927          (e) Improve the error-handling of the C++ wrapper a little bit.
928    
929          (f) New tests for checking recursion limiting.
930    
931     8. The pcre_memmove() function, which is used only if the environment does not
932        have a standard memmove() function (and is therefore rarely compiled),
933        contained two bugs: (a) use of int instead of size_t, and (b) it was not
934        returning a result (though PCRE never actually uses the result).
935    
936     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
937        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
938        returned instead of calling malloc() with an overflowing number that would
939        most likely cause subsequent chaos.
940    
941    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
942    
943    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
944        with this option is matched, the nmatch and pmatch options of regexec() are
945        ignored.
946    
947    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
948        provided in case anyone wants to the the POSIX interface with UTF-8
949        strings.
950    
951    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
952        C++ linking (needed for some HP-UX environments).
953    
954    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
955        (unused parameter) and in the pcre_printint() function (omitted "default"
956        switch label when the default is to do nothing).
957    
958    15. Added some code to make it possible, when PCRE is compiled as a C++
959        library, to replace subject pointers for pcre_exec() with a smart pointer
960        class, thus making it possible to process discontinuous strings.
961    
962    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
963        much the same function. They were added by different people who were trying
964        to make PCRE easy to compile on non-Unix systems. It has been suggested
965        that PCRE_EXPORT be abolished now that there is more automatic apparatus
966        for compiling on Windows systems. I have therefore replaced it with
967        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
968        defaults to "extern" for C or "extern C" for C++, which works fine on
969        Unix-like systems. It is now possible to override the value of PCRE_DATA_
970        SCOPE with something explicit in config.h. In addition:
971    
972        (a) pcreposix.h still had just "extern" instead of either of these macros;
973            I have replaced it with PCRE_DATA_SCOPE.
974    
975        (b) Functions such as _pcre_xclass(), which are internal to the library,
976            but external in the C sense, all had PCRE_EXPORT in their definitions.
977            This is apparently wrong for the Windows case, so I have removed it.
978            (It makes no difference on Unix-like systems.)
979    
980    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
981        of recursive calls to match(). This is different to MATCH_LIMIT because
982        that limits the total number of calls to match(), not all of which increase
983        the depth of recursion. Limiting the recursion depth limits the amount of
984        stack (or heap if NO_RECURSE is set) that is used. The default can be set
985        when PCRE is compiled, and changed at run time. A patch from Google adds
986        this functionality to the C++ interface.
987    
988    18. Changes to the handling of Unicode character properties:
989    
990        (a) Updated the table to Unicode 4.1.0.
991    
992        (b) Recognize characters that are not in the table as "Cn" (undefined).
993    
994        (c) I revised the way the table is implemented to a much improved format
995            which includes recognition of ranges. It now supports the ranges that
996            are defined in UnicodeData.txt, and it also amalgamates other
997            characters into ranges. This has reduced the number of entries in the
998            table from around 16,000 to around 3,000, thus reducing its size
999            considerably. I realized I did not need to use a tree structure after
1000            all - a binary chop search is just as efficient. Having reduced the
1001            number of entries, I extended their size from 6 bytes to 8 bytes to
1002            allow for more data.
1003    
1004        (d) Added support for Unicode script names via properties such as \p{Han}.
1005    
1006    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1007        matching that character.
1008    
1009    20. When matching a repeated Unicode property with a minimum greater than zero,
1010        (for example \pL{2,}), PCRE could look past the end of the subject if it
1011        reached it while seeking the minimum number of characters. This could
1012        happen only if some of the characters were more than one byte long, because
1013        there is a check for at least the minimum number of bytes.
1014    
1015    21. Refactored the implementation of \p and \P so as to be more general, to
1016        allow for more different types of property in future. This has changed the
1017        compiled form incompatibly. Anybody with saved compiled patterns that use
1018        \p or \P will have to recompile them.
1019    
1020    22. Added "Any" and "L&" to the supported property types.
1021    
1022    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1023        but give a compile time error if the value is greater than 0xff.
1024    
1025    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1026        accidentally not being installed or uninstalled.
1027    
1028    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1029        made were to insert the current release number. This seemed silly, because
1030        it made things harder for people building PCRE on systems that don't run
1031        "configure". I have turned pcre.h into a distributed file, no longer built
1032        by "configure", with the version identification directly included. There is
1033        no longer a pcre.h.in file.
1034    
1035        However, this change necessitated a change to the pcre-config script as
1036        well. It is built from pcre-config.in, and one of the substitutions was the
1037        release number. I have updated configure.ac so that ./configure now finds
1038        the release number by grepping pcre.h.
1039    
1040    26. Added the ability to run the tests under valgrind.
1041    
1042    
1043    Version 6.4 05-Sep-05
1044    ---------------------
1045    
1046     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1047        "--" to be printed when multiple files were scanned, even when none of the
1048        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1049        consider it to be a bug, and have restored the previous behaviour.
1050    
1051     2. A couple of code tidies to get rid of compiler warnings.
1052    
1053     3. The pcretest program used to cheat by referring to symbols in the library
1054        whose names begin with _pcre_. These are internal symbols that are not
1055        really supposed to be visible externally, and in some environments it is
1056        possible to suppress them. The cheating is now confined to including
1057        certain files from the library's source, which is a bit cleaner.
1058    
1059     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1060        file's purpose clearer.
1061    
1062     5. Reorganized pcre_ucp_findchar().
1063    
1064    
1065    Version 6.3 15-Aug-05
1066    ---------------------
1067    
1068     1. The file libpcre.pc.in did not have general read permission in the tarball.
1069    
1070     2. There were some problems when building without C++ support:
1071    
1072        (a) If C++ support was not built, "make install" and "make test" still
1073            tried to test it.
1074    
1075        (b) There were problems when the value of CXX was explicitly set. Some
1076            changes have been made to try to fix these, and ...
1077    
1078        (c) --disable-cpp can now be used to explicitly disable C++ support.
1079    
1080        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1081            backslash in a target when C++ was disabled. This confuses some
1082            versions of "make", apparently. Using an intermediate variable solves
1083            this. (Same for CPP_LOBJ.)
1084    
1085     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1086        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1087        necessary on certain architectures.
1088    
1089     4. Added a setting of -export-symbols-regex to the link command to remove
1090        those symbols that are exported in the C sense, but actually are local
1091        within the library, and not documented. Their names all begin with
1092        "_pcre_". This is not a perfect job, because (a) we have to except some
1093        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1094        available (and never for static libraries). I have made a note to try to
1095        find a way round (a) in the future.
1096    
1097    
1098    Version 6.2 01-Aug-05
1099    ---------------------
1100    
1101     1. There was no test for integer overflow of quantifier values. A construction
1102        such as {1111111111111111} would give undefined results. What is worse, if
1103        a minimum quantifier for a parenthesized subpattern overflowed and became
1104        negative, the calculation of the memory size went wrong. This could have
1105        led to memory overwriting.
1106    
1107     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1108    
1109     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1110        operating environments where this matters.
1111    
1112     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1113        PCRE options from within the C++ wrapper.
1114    
1115     5. Named capturing subpatterns were not being correctly counted when a pattern
1116        was compiled. This caused two problems: (a) If there were more than 100
1117        such subpatterns, the calculation of the memory needed for the whole
1118        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1119        back references of the form \12, where the number was greater than 9, were
1120        not recognized as back references, even though there were sufficient
1121        previous subpatterns.
1122    
1123     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1124        versions of gcc, e.g. 2.95.4.
1125    
1126    
1127    Version 6.1 21-Jun-05
1128    ---------------------
1129    
1130     1. There was one reference to the variable "posix" in pcretest.c that was not
1131        surrounded by "#if !defined NOPOSIX".
1132    
1133     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1134        the cross-check on the old pcre_info() function, for the benefit of the
1135        cut-down version of PCRE that is currently imported into Exim.
1136    
1137     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1138        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1139        patterns that start (?i) but I don't think that matters. The use of (?i) is
1140        just an example; this all applies to the other options as well.
1141    
1142     4. Since libtool seems to echo the compile commands it is issuing, the output
1143        from "make" can be reduced a bit by putting "@" in front of each libtool
1144        compile command.
1145    
1146     5. Patch from the folks at Google for configure.in to be a bit more thorough
1147        in checking for a suitable C++ installation before trying to compile the
1148        C++ stuff. This should fix a reported problem when a compiler was present,
1149        but no suitable headers.
1150    
1151     6. The man pages all had just "PCRE" as their title. I have changed them to
1152        be the relevant file name. I have also arranged that these names are
1153        retained in the file doc/pcre.txt, which is a concatenation in text format
1154        of all the man pages except the little individual ones for each function.
1155    
1156     7. The NON-UNIX-USE file had not been updated for the different set of source
1157        files that come with release 6. I also added a few comments about the C++
1158        wrapper.
1159    
1160    
1161    Version 6.0 07-Jun-05
1162    ---------------------
1163    
1164     1. Some minor internal re-organization to help with my DFA experiments.
1165    
1166     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1167        didn't matter for the library itself when fully configured, but did matter
1168        when compiling without UCP support, or within Exim, where the ucp files are
1169        not imported.
1170    
1171     3. Refactoring of the library code to split up the various functions into
1172        different source modules. The addition of the new DFA matching code (see
1173        below) to a single monolithic source would have made it really too
1174        unwieldy, quite apart from causing all the code to be include in a
1175        statically linked application, when only some functions are used. This is
1176        relevant even without the DFA addition now that patterns can be compiled in
1177        one application and matched in another.
1178    
1179        The downside of splitting up is that there have to be some external
1180        functions and data tables that are used internally in different modules of
1181        the library but which are not part of the API. These have all had their
1182        names changed to start with "_pcre_" so that they are unlikely to clash
1183        with other external names.
1184    
1185     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1186        a different (DFA) algorithm. Although it is slower than the original
1187        function, it does have some advantages for certain types of matching
1188        problem.
1189    
1190     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1191        including restarting after a partial match.
1192    
1193     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1194        defined when compiling for Windows was sent to me. I have put it into the
1195        code, though I have no means of testing or verifying it.
1196    
1197     7. Added the pcre_refcount() auxiliary function.
1198    
1199     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1200        match before or at the first newline in the subject string. In pcretest,
1201        the /f option on a pattern can be used to set this.
1202    
1203     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1204        would behave wrongly. This has been present in PCRE since release 4.0.
1205    
1206    10. A number of changes to the pcregrep command:
1207    
1208        (a) Refactored how -x works; insert ^(...)$ instead of setting
1209            PCRE_ANCHORED and checking the length, in preparation for adding
1210            something similar for -w.
1211    
1212        (b) Added the -w (match as a word) option.
1213    
1214        (c) Refactored the way lines are read and buffered so as to have more
1215            than one at a time available.
1216    
1217        (d) Implemented a pcregrep test script.
1218    
1219        (e) Added the -M (multiline match) option. This allows patterns to match
1220            over several lines of the subject. The buffering ensures that at least
1221            8K, or the rest of the document (whichever is the shorter) is available
1222            for matching (and similarly the previous 8K for lookbehind assertions).
1223    
1224        (f) Changed the --help output so that it now says
1225    
1226              -w, --word-regex(p)
1227    
1228            instead of two lines, one with "regex" and the other with "regexp"
1229            because that confused at least one person since the short forms are the
1230            same. (This required a bit of code, as the output is generated
1231            automatically from a table. It wasn't just a text change.)
1232    
1233        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1234            option but starts with a hyphen. Could be a pattern or a path name
1235            starting with a hyphen, for instance.
1236    
1237        (h) "-" can be given as a file name to represent stdin.
1238    
1239        (i) When file names are being printed, "(standard input)" is used for
1240            the standard input, for compatibility with GNU grep. Previously
1241            "<stdin>" was used.
1242    
1243        (j) The option --label=xxx can be used to supply a name to be used for
1244            stdin when file names are being printed. There is no short form.
1245    
1246        (k) Re-factored the options decoding logic because we are going to add
1247            two more options that take data. Such options can now be given in four
1248            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1249    
1250        (l) Added the -A, -B, and -C options for requesting that lines of context
1251            around matches be printed.
1252    
1253        (m) Added the -L option to print the names of files that do not contain
1254            any matching lines, that is, the complement of -l.
1255    
1256        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1257            continue to scan other files.
1258    
1259        (o) The -s option was incorrectly implemented. For compatibility with other
1260            greps, it now suppresses the error message for a non-existent or non-
1261            accessible file (but not the return code). There is a new option called
1262            -q that suppresses the output of matching lines, which was what -s was
1263            previously doing.
1264    
1265        (p) Added --include and --exclude options to specify files for inclusion
1266            and exclusion when recursing.
1267    
1268    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1269        Hopefully, it now does.
1270    
1271    12. Missing cast in pcre_study().
1272    
1273    13. Added an "uninstall" target to the makefile.
1274    
1275    14. Replaced "extern" in the function prototypes in Makefile.in with
1276        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1277        world, but is set differently for Windows.
1278    
1279    15. Added a second compiling function called pcre_compile2(). The only
1280        difference is that it has an extra argument, which is a pointer to an
1281        integer error code. When there is a compile-time failure, this is set
1282        non-zero, in addition to the error test pointer being set to point to an
1283        error message. The new argument may be NULL if no error number is required
1284        (but then you may as well call pcre_compile(), which is now just a
1285        wrapper). This facility is provided because some applications need a
1286        numeric error indication, but it has also enabled me to tidy up the way
1287        compile-time errors are handled in the POSIX wrapper.
1288    
1289    16. Added VPATH=.libs to the makefile; this should help when building with one
1290        prefix path and installing with another. (Or so I'm told by someone who
1291        knows more about this stuff than I do.)
1292    
1293    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1294        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1295        match everything, including newlines. This is not POSIX-compatible, but
1296        somebody wanted the feature. From pcretest it can be activated by using
1297        both the P and the s flags.
1298    
1299    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1300    
1301    19. libpcre.pc was being incorrectly installed as executable.
1302    
1303    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1304        it now also looks for '\r' so that it will work unmodified on Windows.
1305    
1306    21. Added Google's contributed C++ wrapper to the distribution.
1307    
1308    22. Added some untidy missing memory free() calls in pcretest, to keep
1309        Electric Fence happy when testing.
1310    
1311    
1312    
1313    Version 5.0 13-Sep-04
1314    ---------------------
1315    
1316     1. Internal change: literal characters are no longer packed up into items
1317        containing multiple characters in a single byte-string. Each character
1318        is now matched using a separate opcode. However, there may be more than one
1319        byte in the character in UTF-8 mode.
1320    
1321     2. The pcre_callout_block structure has two new fields: pattern_position and
1322        next_item_length. These contain the offset in the pattern to the next match
1323        item, and its length, respectively.
1324    
1325     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1326        insertion of callouts before each pattern item. Added the /C option to
1327        pcretest to make use of this.
1328    
1329     4. On the advice of a Windows user, the lines
1330    
1331          #if defined(_WIN32) || defined(WIN32)
1332          _setmode( _fileno( stdout ), 0x8000 );
1333          #endif  /* defined(_WIN32) || defined(WIN32) */
1334    
1335        have been added to the source of pcretest. This apparently does useful
1336        magic in relation to line terminators.
1337    
1338     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1339        for the benefit of those environments where the "b" makes a difference.
1340    
1341     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1342        to know about it. I have put a hack into configure.in that adds in code
1343        to set GCC=yes if CC=icc. This seems to end up at a point in the
1344        generated configure script that is early enough to affect the setting of
1345        compiler options, which is what is needed, but I have no means of testing
1346        whether it really works. (The user who reported this had patched the
1347        generated configure script, which of course I cannot do.)
1348    
1349        LATER: After change 22 below (new libtool files), the configure script
1350        seems to know about icc (and also ecc). Therefore, I have commented out
1351        this hack in configure.in.
1352    
1353     7. Added support for pkg-config (2 patches were sent in).
1354    
1355     8. Negated POSIX character classes that used a combination of internal tables
1356        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1357        [[:^ascii]]. Typically, they would match almost any characters. The other
1358        POSIX classes were not broken in this way.
1359    
1360     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1361        to find the match, as PCRE was deluded into thinking that the match had to
1362        start at the start point or following a newline. The same bug applied to
1363        patterns with negative forward assertions or any backward assertions
1364        preceding ".*" at the start, unless the pattern required a fixed first
1365        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1366    
1367    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1368        starting at the last subject character, bytes beyond the end of the subject
1369        string were read.
1370    
1371    11. Renamed the variable "class" as "classbits" to make life easier for C++
1372        users. (Previously there was a macro definition, but it apparently wasn't
1373        enough.)
1374    
1375    12. Added the new field "tables" to the extra data so that tables can be passed
1376        in at exec time, or the internal tables can be re-selected. This allows
1377        a compiled regex to be saved and re-used at a later time by a different
1378        program that might have everything at different addresses.
1379    
1380    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1381        -R library as well as a -L library.
1382    
1383    14. The debugging options of pcretest (-d on the command line or D on a
1384        pattern) showed incorrect output for anything following an extended class
1385        that contained multibyte characters and which was followed by a quantifier.
1386    
1387    15. Added optional support for general category Unicode character properties
1388        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1389        support. It adds about 90K to the size of the library. The meanings of the
1390        inbuilt class escapes such as \d and \s have NOT been changed.
1391    
1392    16. Updated pcredemo.c to include calls to free() to release the memory for the
1393        compiled pattern.
1394    
1395    17. The generated file chartables.c was being created in the source directory
1396        instead of in the building directory. This caused the build to fail if the
1397        source directory was different from the building directory, and was
1398        read-only.
1399    
1400    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1401        file. No doubt somebody will tell me if they don't make sense... Also added
1402        Dan Mooney's comments about building on OpenVMS.
1403    
1404    19. Added support for partial matching via the PCRE_PARTIAL option for
1405        pcre_exec() and the \P data escape in pcretest.
1406    
1407    20. Extended pcretest with 3 new pattern features:
1408    
1409        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1410              write the compiled pattern to the file whose name is "rest-of-line".
1411              This is a straight binary dump of the data, with the saved pointer to
1412              the character tables forced to be NULL. The study data, if any, is
1413              written too. After writing, pcretest reads a new pattern.
1414    
1415        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1416              compiled pattern from the given file. There must not be any
1417              occurrences of "<" in the file name (pretty unlikely); if there are,
1418              pcretest will instead treat the initial "<" as a pattern delimiter.
1419              After reading in the pattern, pcretest goes on to read data lines as
1420              usual.
1421    
1422        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1423              and 16-bit fields in a compiled pattern, to simulate a pattern that
1424              was compiled on a host of opposite endianness.
1425    
1426    21. The pcre-exec() function can now cope with patterns that were compiled on
1427        hosts of opposite endianness, with this restriction:
1428    
1429          As for any compiled expression that is saved and used later, the tables
1430          pointer field cannot be preserved; the extra_data field in the arguments
1431          to pcre_exec() should be used to pass in a tables address if a value
1432          other than the default internal tables were used at compile time.
1433    
1434    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1435        now diagnosed as an error. Previously, most of the time, a negative number
1436        would have been treated as zero, but if in addition "ovector" was passed as
1437        NULL, a crash could occur.
1438    
1439    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1440        new versions from the libtool 1.5 distribution (the last one is a copy of
1441        a file called libtool.m4). This seems to have fixed the need to patch
1442        "configure" to support Darwin 1.3 (which I used to do). However, I still
1443        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1444        workstation).
1445    
1446    24. Changed the PCRE licence to be the more standard "BSD" licence.
1447    
1448    
1449    Version 4.5 01-Dec-03
1450    ---------------------
1451    
1452     1. There has been some re-arrangement of the code for the match() function so
1453        that it can be compiled in a version that does not call itself recursively.
1454        Instead, it keeps those local variables that need separate instances for
1455        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1456        needs to "recurse". Keeping track of where control must go is done by means
1457        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1458        hide most of the details from the main code, and operates only if
1459        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1460        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1461        operating.
1462    
1463        To make it easier for callers to provide specially tailored get/free
1464        functions for this usage, two new functions, pcre_stack_malloc, and
1465        pcre_stack_free, are used. They are always called in strict stacking order,
1466        and the size of block requested is always the same.
1467    
1468        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1469        PCRE has been compiled to use the stack or the heap for recursion. The
1470        -C option of pcretest uses this to show which version is compiled.
1471    
1472        A new data escape \S, is added to pcretest; it causes the amounts of store
1473        obtained and freed by both kinds of malloc/free at match time to be added
1474        to the output.
1475    
1476     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1477        what's available on my current Linux desktop machine.
1478    
1479     3. When matching a UTF-8 string, the test for a valid string at the start has
1480        been extended. If start_offset is not zero, PCRE now checks that it points
1481        to a byte that is the start of a UTF-8 character. If not, it returns
1482        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1483        this is necessary because there may be backward assertions in the pattern.
1484        When matching the same subject several times, it may save resources to use
1485        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1486    
1487     4. The code for checking the validity of UTF-8 strings has been tightened so
1488        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1489        containing "overlong sequences".
1490    
1491     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1492        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1493        should have been "&", but it just so happened that all the cases this let
1494        through by mistake were picked up later in the function.
1495    
1496     6. I had used a variable called "isblank" - this is a C99 function, causing
1497        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1498    
1499     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1500        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1501        so the version is shown; (c) stop "make test" echoing "./RunTest".
1502    
1503     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1504    
1505     9. The prototype for memmove() for systems that don't have it was using
1506        size_t, but the inclusion of the header that defines size_t was later. I've
1507        moved the #includes for the C headers earlier to avoid this.
1508    
1509    10. Added some adjustments to the code to make it easier to compiler on certain
1510        special systems:
1511    
1512          (a) Some "const" qualifiers were missing.
1513          (b) Added the macro EXPORT before all exported functions; by default this
1514              is defined to be empty.
1515          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1516              that it reads its output file name as an argument instead of writing
1517              to the standard output and assuming this can be redirected.
1518    
1519    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1520        class containing characters with values greater than 255, PCRE compilation
1521        went into a loop.
1522    
1523    12. A recursive reference to a subpattern that was within another subpattern
1524        that had a minimum quantifier of zero caused PCRE to crash. For example,
1525        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1526        recursion. If the recursively-called subpattern itself had a zero repeat,
1527        that was OK.
1528    
1529    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1530        buffer into which it was copied (for escape processing) was still set at
1531        1024, so long lines caused crashes.
1532    
1533    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1534        "internal error: code overflow...". This applied to any character class
1535        that was followed by a possessive quantifier.
1536    
1537    15. Modified the Makefile to add libpcre.la as a prerequisite for
1538        libpcreposix.la because I was told this is needed for a parallel build to
1539        work.
1540    
1541    16. If a pattern that contained .* following optional items at the start was
1542        studied, the wrong optimizing data was generated, leading to matching
1543        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1544        matching string must start with a or b or c. The correct conclusion for
1545        this pattern is that a match can start with any character.
1546    
1547    
1548    Version 4.4 13-Aug-03
1549    ---------------------
1550    
1551     1. In UTF-8 mode, a character class containing characters with values between
1552        127 and 255 was not handled correctly if the compiled pattern was studied.
1553        In fixing this, I have also improved the studying algorithm for such
1554        classes (slightly).
1555    
1556     2. Three internal functions had redundant arguments passed to them. Removal
1557        might give a very teeny performance improvement.
1558    
1559     3. Documentation bug: the value of the capture_top field in a callout is *one
1560        more than* the number of the hightest numbered captured substring.
1561    
1562     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1563        in incorrectly linking with a previously installed version. They now link
1564        explicitly with libpcre.la.
1565    
1566     5. configure.in no longer needs to recognize Cygwin specially.
1567    
1568     6. A problem in pcre.in for Windows platforms is fixed.
1569    
1570     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1571        pcretest, it used to include the size of the study block as part of its
1572        output. Unfortunately, the structure contains a field that has a different
1573        size on different hardware architectures. This meant that the tests that
1574        showed this size failed. As the block is currently always of a fixed size,
1575        this information isn't actually particularly useful in pcretest output, so
1576        I have just removed it.
1577    
1578     8. Three pre-processor statements accidentally did not start in column 1.
1579        Sadly, there are *still* compilers around that complain, even though
1580        standard C has not required this for well over a decade. Sigh.
1581    
1582     9. In pcretest, the code for checking callouts passed small integers in the
1583        callout_data field, which is a void * field. However, some picky compilers
1584        complained about the casts involved for this on 64-bit systems. Now
1585        pcretest passes the address of the small integer instead, which should get
1586        rid of the warnings.
1587    
1588    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1589        both compile and run time, and gives an error if an invalid UTF-8 sequence
1590        is found. There is a option for disabling this check in cases where the
1591        string is known to be correct and/or the maximum performance is wanted.
1592    
1593    11. In response to a bug report, I changed one line in Makefile.in from
1594    
1595            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1596        to
1597            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1598    
1599        to look similar to other lines, but I have no way of telling whether this
1600        is the right thing to do, as I do not use Windows. No doubt I'll get told
1601        if it's wrong...
1602    
1603    
1604    Version 4.3 21-May-03
1605    ---------------------
1606    
1607    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1608       Makefile.
1609    
1610    2. Some refactoring to improve the quality of the code:
1611    
1612       (i)   The utf8_table... variables are now declared "const".
1613    
1614       (ii)  The code for \cx, which used the "case flipping" table to upper case
1615             lower case letters, now just substracts 32. This is ASCII-specific,
1616             but the whole concept of \cx is ASCII-specific, so it seems
1617             reasonable.
1618    
1619       (iii) PCRE was using its character types table to recognize decimal and
1620             hexadecimal digits in the pattern. This is silly, because it handles
1621             only 0-9, a-f, and A-F, but the character types table is locale-
1622             specific, which means strange things might happen. A private
1623             table is now used for this - though it costs 256 bytes, a table is
1624             much faster than multiple explicit tests. Of course, the standard
1625             character types table is still used for matching digits in subject
1626             strings against \d.
1627    
1628       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1629             ending in _t are). So I've renamed it as ESC_tee.
1630    
1631    3. The first argument for regexec() in the POSIX wrapper should have been
1632       defined as "const".
1633    
1634    4. Changed pcretest to use malloc() for its buffers so that they can be
1635       Electric Fenced for debugging.
1636    
1637    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1638       to read one or more bytes before the start of the subject string. Often this
1639       had no effect on PCRE's behaviour, but in some circumstances it could
1640       provoke a segmentation fault.
1641    
1642    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1643       to try to read one or more bytes before the start of the subject string.
1644    
1645    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1646       UTF-8 support could misbehave in various ways if the subject string
1647       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1648       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1649       back over UTF-8 characters.)
1650    
1651    
1652    Version 4.2 14-Apr-03
1653    ---------------------
1654    
1655    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1656    
1657    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1658         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1659         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1660         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1661         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1662           and BUILD_EXEEXT
1663         Note: automatic setting of the BUILD variables is not yet working
1664         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1665           compile-time but not at link-time
1666         [LINK]: use for linking executables only
1667         make different versions for Windows and non-Windows
1668         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1669           libraries
1670         [LINK_FOR_BUILD]: new variable
1671         [OBJEXT]: use throughout
1672         [EXEEXT]: use throughout
1673         <winshared>: new target
1674         <wininstall>: new target
1675         <dftables.o>: use native compiler
1676         <dftables>: use native linker
1677         <install>: handle Windows platform correctly
1678         <clean>: ditto
1679         <check>: ditto
1680         copy DLL to top builddir before testing
1681    
1682       As part of these changes, -no-undefined was removed again. This was reported
1683       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1684       in any case.
1685    
1686    3. Some tidies to get rid of compiler warnings:
1687    
1688       . In the match_data structure, match_limit was an unsigned long int, whereas
1689         match_call_count was an int. I've made them both unsigned long ints.
1690    
1691       . In pcretest the fact that a const uschar * doesn't automatically cast to
1692         a void * provoked a warning.
1693    
1694       . Turning on some more compiler warnings threw up some "shadow" variables
1695         and a few more missing casts.
1696    
1697    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1698       option, a class that contained a single character with a value between 128
1699       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1700    
1701    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1702       option, a class that contained several characters, but with at least one
1703       whose value was between 128 and 255 caused PCRE to crash.
1704    
1705    
1706    Version 4.1 12-Mar-03
1707    ---------------------
1708    
1709    1. Compiling with gcc -pedantic found a couple of places where casts were
1710    needed, and a string in dftables.c that was longer than standard compilers are
1711    required to support.
1712    
1713    2. Compiling with Sun's compiler found a few more places where the code could
1714    be tidied up in order to avoid warnings.
1715    
1716    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1717    first of these names is deprecated in the latest Autoconf in favour of the name
1718    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1719    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1720    analogy I have changed it to CFLAGS_FOR_BUILD.
1721    
1722    4. Added -no-undefined to the linking command in the Makefile, because this is
1723    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1724    linking step for the pcreposix library.
1725    
1726    5. PCRE was failing to diagnose the case of two named groups with the same
1727    name.
1728    
1729    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1730    literal character that is needed in the subject for a match, and scans along to
1731    ensure that it is present before embarking on the full matching process. This
1732    saves time in cases of nested unlimited repeats that are never going to match.
1733    Problem: the scan can take a lot of time if the subject is very long (e.g.
1734    megabytes), thus penalizing straightforward matches. It is now done only if the
1735    amount of subject to be scanned is less than 1000 bytes.
1736    
1737    7. A lesser problem with the same optimization is that it was recording the
1738    first character of an anchored pattern as "needed", thus provoking a search
1739    right along the subject, even when the first match of the pattern was going to
1740    fail. The "needed" character is now not set for anchored patterns, unless it
1741    follows something in the pattern that is of non-fixed length. Thus, it still
1742    fulfils its original purpose of finding quick non-matches in cases of nested
1743    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1744    
1745    
1746    Version 4.0 17-Feb-03
1747    ---------------------
1748    
1749    1. If a comment in an extended regex that started immediately after a meta-item
1750    extended to the end of string, PCRE compiled incorrect data. This could lead to
1751    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1752    
1753    2. Moved to autoconf 2.53 and libtool 1.4.2.
1754    
1755    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1756    the special perltest8 script is no longer needed - all the tests can be run
1757    from a single perltest script.
1758    
1759    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1760    by \s. It has now been removed in PCRE. This means it isn't recognized as
1761    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1762    class [:space:] *does* include VT, thereby creating a mess.
1763    
1764    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1765    space and tab.
1766    
1767    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1768    its new features into the main test script, reducing the number of scripts.
1769    
1770    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1771    were backward compatible, and made the (?i) apply to the whole pattern, as if
1772    /i were given. Now it behaves more logically, and applies the option setting
1773    only to what follows. PCRE has been changed to follow suit. However, if it
1774    finds options settings right at the start of the pattern, it extracts them into
1775    the global options, as before. Thus, they show up in the info data.
1776    
1777    8. Added support for the \Q...\E escape sequence. Characters in between are
1778    treated as literals. This is slightly different from Perl in that $ and @ are
1779    also handled as literals inside the quotes. In Perl, they will cause variable
1780    interpolation. Note the following examples:
1781    
1782        Pattern            PCRE matches      Perl matches
1783    
1784        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1785        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1786        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1787    
1788    For compatibility with Perl, \Q...\E sequences are recognized inside character
1789    classes as well as outside them.
1790    
1791    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1792    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1793    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1794    signed/unsigned warnings.
1795    
1796    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1797    option for pcretest, so I've replaced it by a simple function that does just
1798    that job.
1799    
1800    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1801    "pcregrep -".
1802    
1803    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1804    Java package. This provides some syntactic sugar for simple cases of what my
1805    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1806    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1807    item, you can use this simplified notation. Note that only makes sense with
1808    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1809    greediness, whatever the setting of the PCRE_UNGREEDY option.
1810    
1811    13. A change of greediness default within a pattern was not taking effect at
1812    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1813    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1814    was abstracted outside.
1815    
1816    14. PCRE now supports the \G assertion. It is true when the current matching
1817    position is at the start point of the match. This differs from \A when the
1818    starting offset is non-zero. Used with the /g option of pcretest (or similar
1819    code), it works in the same way as it does for Perl's /g option. If all
1820    alternatives of a regex begin with \G, the expression is anchored to the start
1821    match position, and the "anchored" flag is set in the compiled expression.
1822    
1823    15. Some bugs concerning the handling of certain option changes within patterns
1824    have been fixed. These applied to options other than (?ims). For example,
1825    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1826    been the other way round. Some of this was related to change 7 above.
1827    
1828    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1829    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1830    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1831    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1832    
1833    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1834    mode. Unlike ".", it always matches newline, whatever the setting of
1835    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1836    assertions. Perl allows it, but it doesn't (in general) work because it can't
1837    calculate the length of the lookbehind. At least, that's the case for Perl
1838    5.8.0 - I've been told they are going to document that it doesn't work in
1839    future.
1840    
1841    18. Added an error diagnosis for escapes that PCRE does not support: these are
1842    \L, \l, \N, \P, \p, \U, \u, and \X.
1843    
1844    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1845    reading past the end of the pattern in cases such as /[abcd/.
1846    
1847    20. PCRE was getting more memory than necessary for patterns with classes that
1848    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1849    
1850    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1851    compiling PCRE for use with Virtual Pascal.
1852    
1853    22. Small fix to the Makefile to make it work properly if the build is done
1854    outside the source tree.
1855    
1856    23. Added a new extension: a condition to go with recursion. If a conditional
1857    subpattern starts with (?(R) the "true" branch is used if recursion has
1858    happened, whereas the "false" branch is used only at the top level.
1859    
1860    24. When there was a very long string of literal characters (over 255 bytes
1861    without UTF support, over 250 bytes with UTF support), the computation of how
1862    much memory was required could be incorrect, leading to segfaults or other
1863    strange effects.
1864    
1865    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1866    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1867    there was a subsequent back reference to those brackets. This meant that, for
1868    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1869    possible to check for precisely this case. All we can do is abandon the
1870    optimization if .* occurs inside capturing brackets when there are any back
1871    references whatsoever. (See below for a better fix that came later.)
1872    
1873    26. The handling of the optimization for finding the first character of a
1874    non-anchored pattern, and for finding a character that is required later in the
1875    match were failing in some cases. This didn't break the matching; it just
1876    failed to optimize when it could. The way this is done has been re-implemented.
1877    
1878    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1879    
1880    28. Added a new feature that provides some of the functionality that Perl
1881    provides with (?{...}). The facility is termed a "callout". The way it is done
1882    in PCRE is for the caller to provide an optional function, by setting
1883    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1884    global variable. By default it is unset, which disables all calling out. To get
1885    the function called, the regex must include (?C) at appropriate points. This
1886    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1887    This provides a means of identifying different callout points. When PCRE
1888    reaches such a point in the regex, if pcre_callout has been set, the external
1889    function is called. It is provided with data in a structure called
1890    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1891    matching continues; if it returns a non-zero value, the match at the current
1892    point fails. However, backtracking will occur if possible. [This was changed
1893    later and other features added - see item 49 below.]
1894    
1895    29. pcretest is upgraded to test the callout functionality. It provides a
1896    callout function that displays information. By default, it shows the start of
1897    the match and the current position in the text. There are some new data escapes
1898    to vary what happens:
1899    
1900        \C+         in addition, show current contents of captured substrings
1901        \C-         do not supply a callout function
1902        \C!n        return 1 when callout number n is reached
1903        \C!n!m      return 1 when callout number n is reached for the mth time
1904    
1905    30. If pcregrep was called with the -l option and just a single file name, it
1906    output "<stdin>" if a match was found, instead of the file name.
1907    
1908    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1909    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1910    pcre_exec(). This saves a malloc/free per call. The default value of
1911    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1912    when configuring.
1913    
1914    32. The default maximum size of a compiled pattern is 64K. There have been a
1915    few cases of people hitting this limit. The code now uses macros to handle the
1916    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1917    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1918    configuring. Tests 2 and 5 work only with 2-byte links because they output
1919    debugging information about compiled patterns.
1920    
1921    33. Internal code re-arrangements:
1922    
1923    (a) Moved the debugging function for printing out a compiled regex into
1924        its own source file (printint.c) and used #include to pull it into
1925        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1926        separate copies.
1927    
1928    (b) Defined the list of op-code names for debugging as a macro in
1929        internal.h so that it is next to the definition of the opcodes.
1930    
1931    (c) Defined a table of op-code lengths for simpler skipping along compiled
1932        code. This is again a macro in internal.h so that it is next to the
1933        definition of the opcodes.
1934    
1935    34. Added support for recursive calls to individual subpatterns, along the
1936    lines of Robin Houston's patch (but implemented somewhat differently).
1937    
1938    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1939    allow it to read and process whole directories in Win32. This code was
1940    contributed by Lionel Fourquaux; it has not been tested by me.
1941    
1942    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1943    used to name a group. Names consist of alphanumerics and underscores, and must
1944    be unique. Back references use the syntax (?P=name) and recursive calls use
1945    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1946    numbers. The function pcre_fullinfo() can be used after compilation to extract
1947    a name/number map. There are three relevant calls:
1948    
1949      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1950      PCRE_INFO_NAMECOUNT            yields the number of entries
1951      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1952    
1953    The map is a vector of fixed-size entries. The size of each entry depends on
1954    the length of the longest name used. The first two bytes of each entry are the
1955    group number, most significant byte first. There follows the corresponding
1956    name, zero terminated. The names are in alphabetical order.
1957    
1958    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1959    case instead of 255. Making it the same both with and without UTF-8 support
1960    means that the same test output works with both.
1961    
1962    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1963    calling malloc() with a zero argument.
1964    
1965    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1966    optimization. I've improved things by keeping a bitmap of backreferences with
1967    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1968    fact referenced, the optimization can be applied. It is unlikely that a
1969    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1970    the match to follow \n) will appear inside brackets with a number greater than
1971    31, but if it does, any back reference > 31 suppresses the optimization.
1972    
1973    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1974    of disabling numbered capturing parentheses. Any opening parenthesis that is
1975    not followed by ? behaves as if it were followed by ?: but named parentheses
1976    can still be used for capturing (and they will acquire numbers in the usual
1977    way).
1978    
1979    41. Redesigned the return codes from the match() function into yes/no/error so
1980    that errors can be passed back from deep inside the nested calls. A malloc
1981    failure while inside a recursive subpattern call now causes the
1982    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1983    
1984    42. It is now possible to set a limit on the number of times the match()
1985    function is called in a call to pcre_exec(). This facility makes it possible to
1986    limit the amount of recursion and backtracking, though not in a directly
1987    obvious way, because the match() function is used in a number of different
1988    circumstances. The count starts from zero for each position in the subject
1989    string (for non-anchored patterns). The default limit is, for compatibility, a
1990    large number, namely 10 000 000. You can change this in two ways:
1991    
1992    (a) When configuring PCRE before making, you can use --with-match-limit=n
1993        to set a default value for the compiled library.
1994    
1995    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1996        a different value is set. See 45 below.
1997    
1998    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1999    
2000    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2001    of things that can be changed at compile time. The first argument specifies
2002    what is wanted and the second points to where the information is to be placed.
2003    The current list of available information is:
2004    
2005      PCRE_CONFIG_UTF8
2006    
2007    The output is an integer that is set to one if UTF-8 support is available;
2008    otherwise it is set to zero.
2009    
2010      PCRE_CONFIG_NEWLINE
2011    
2012    The output is an integer that it set to the value of the code that is used for
2013    newline. It is either LF (10) or CR (13).
2014    
2015      PCRE_CONFIG_LINK_SIZE
2016    
2017    The output is an integer that contains the number of bytes used for internal
2018    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2019    
2020      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2021    
2022    The output is an integer that contains the threshold above which the POSIX
2023    interface uses malloc() for output vectors. See item 31 above.
2024    
2025      PCRE_CONFIG_MATCH_LIMIT
2026    
2027    The output is an unsigned integer that contains the default limit of the number
2028    of match() calls in a pcre_exec() execution. See 42 above.
2029    
2030    44. pcretest has been upgraded by the addition of the -C option. This causes it
2031    to extract all the available output from the new pcre_config() function, and to
2032    output it. The program then exits immediately.
2033    
2034    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2035    order to support additional features. One way would have been to define
2036    pcre_exec2() (for example) with extra arguments, but this would not have been
2037    extensible, and would also have required all calls to the original function to
2038    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2039    is used for passing in "extra" data from pcre_study().
2040    
2041    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2042    contains the following fields:
2043    
2044      flags         a bitmap indicating which of the following fields are set
2045      study_data    opaque data from pcre_study()
2046      match_limit   a way of specifying a limit on match() calls for a specific
2047                      call to pcre_exec()
2048      callout_data  data for callouts (see 49 below)
2049    
2050    The flag bits are also defined in pcre.h, and are
2051    
2052      PCRE_EXTRA_STUDY_DATA
2053      PCRE_EXTRA_MATCH_LIMIT
2054      PCRE_EXTRA_CALLOUT_DATA
2055    
2056    The pcre_study() function now returns one of these new pcre_extra blocks, with
2057    the actual study data pointed to by the study_data field, and the
2058    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2059    before. That is, this change is entirely upwards-compatible and requires no
2060    change to existing code.
2061    
2062    If you want to pass in additional data to pcre_exec(), you can either place it
2063    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2064    block.
2065    
2066    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2067    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2068    times with different match limits, until it finds the minimum value needed for
2069    pcre_exec() to complete. The value is then output. This can be instructive; for
2070    most simple matches the number is quite small, but for pathological cases it
2071    gets very large very quickly.
2072    
2073    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2074    returns the size of the data block pointed to by the study_data field in a
2075    pcre_extra block, that is, the value that was passed as the argument to
2076    pcre_malloc() when PCRE was getting memory in which to place the information
2077    created by pcre_study(). The fourth argument should point to a size_t variable.
2078    pcretest has been extended so that this information is shown after a successful
2079    pcre_study() call when information about the compiled regex is being displayed.
2080    
2081    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2082    because what follows is always an absolute path. (Later: it turns out that this
2083    is more than cosmetic for MinGW, because it doesn't like empty path
2084    components.)
2085    
2086    49. Some changes have been made to the callout feature (see 28 above):
2087    
2088    (i)  A callout function now has three choices for what it returns:
2089    
2090           0  =>  success, carry on matching
2091         > 0  =>  failure at this point, but backtrack if possible
2092         < 0  =>  serious error, return this value from pcre_exec()
2093    
2094         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2095         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2096         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2097         use by callout functions. It will never be used by PCRE itself.
2098    
2099    (ii) The pcre_extra structure (see 45 above) has a void * field called
2100         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2101         pcre_callout_block structure has a field of the same name. The contents of
2102         the field passed in the pcre_extra structure are passed to the callout
2103         function in the corresponding field in the callout block. This makes it
2104         easier to use the same callout-containing regex from multiple threads. For
2105         testing, the pcretest program has a new data escape
2106    
2107           \C*n        pass the number n (may be negative) as callout_data
2108    
2109         If the callout function in pcretest receives a non-zero value as
2110         callout_data, it returns that value.
2111    
2112    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2113    there were some redundant $(CFLAGS) in commands that are now specified as
2114    $(LINK), which already includes $(CFLAGS).
2115    
2116    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2117    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2118    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2119    one-byte characters throughout. Note that case-insensitive matching applies
2120    only to characters whose values are less than 256. PCRE doesn't support the
2121    notion of cases for higher-valued characters.
2122    
2123    (i)   A character class whose characters are all within 0-255 is handled as
2124          a bit map, and the map is inverted for negative classes. Previously, a
2125          character > 255 always failed to match such a class; however it should
2126          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2127    
2128    (ii)  A negated character class with a single character < 255 is coded as
2129          "not this character" (OP_NOT). This wasn't working properly when the test
2130          character was multibyte, either singly or repeated.
2131    
2132    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2133          mode, for example: \x{100}{2,3}.
2134    
2135    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2136          singly or repeated) now correctly test multibyte characters. However,
2137          PCRE doesn't recognize any characters with values greater than 255 as
2138          digits, spaces, or word characters. Such characters always match \D, \S,
2139          and \W, and never match \d, \s, or \w.
2140    
2141    (v)   Classes may now contain characters and character ranges with values
2142          greater than 255. For example: [ab\x{100}-\x{400}].
2143    
2144    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2145          PCRE in UTF-8 mode.
2146    
2147    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2148    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2149    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2150    value.)
2151    
2152    53. The single man page has become too large. I have therefore split it up into
2153    a number of separate man pages. These also give rise to individual HTML pages;
2154    these are now put in a separate directory, and there is an index.html page that
2155    lists them all. Some hyperlinking between the pages has been installed.
2156    
2157    54. Added convenience functions for handling named capturing parentheses.
2158    
2159    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2160    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2161    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2162    are faulted.
2163    
2164    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2165    calling configure. These values are used when compiling the dftables.c program
2166    which is run to generate the source of the default character tables. They
2167    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2168    you will need to set these values.
2169    
2170    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2171    
2172    
2173    Version 3.9 02-Jan-02
2174    ---------------------
2175    
2176    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2177    
2178    2. If --disable-static was given, the building process failed when trying to
2179    build pcretest and pcregrep. (For some reason it was using libtool to compile
2180    them, which is not right, as they aren't part of the library.)
2181    
2182    
2183    Version 3.8 18-Dec-01
2184    ---------------------
2185    
2186    1. The experimental UTF-8 code was completely screwed up. It was packing the
2187    bytes in the wrong order. How dumb can you get?
2188    
2189    
2190    Version 3.7 29-Oct-01
2191    ---------------------
2192    
2193    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2194    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2195    this didn't happen under Solaris 8, where I normally test things.
2196    
2197    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2198    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2199    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2200    this fix an hour or so after the initial 3.7 release.)
2201    
2202    
2203    Version 3.6 23-Oct-01
2204    ---------------------
2205    
2206    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2207    offsets passed as NULL with zero offset count.
2208    
2209    2. The config.guess and config.sub files had not been updated when I moved to
2210    the latest autoconf.
2211    
2212    
2213    Version 3.5 15-Aug-01
2214    ---------------------
2215    
2216    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2217    had been forgotten.
2218    
2219    2. By using declared but undefined structures, we can avoid using "void"
2220    definitions in pcre.h while keeping the internal definitions of the structures
2221    private.
2222    
2223    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2224    user point of view, this means that both static and shared libraries are built
2225    by default, but this can be individually controlled. More of the work of
2226    handling this static/shared cases is now inside libtool instead of PCRE's make
2227    file.
2228    
2229    4. The pcretest utility is now installed along with pcregrep because it is
2230    useful for users (to test regexs) and by doing this, it automatically gets
2231    relinked by libtool. The documentation has been turned into a man page, so
2232    there are now .1, .txt, and .html versions in /doc.
2233    
2234    5. Upgrades to pcregrep:
2235       (i)   Added long-form option names like gnu grep.
2236       (ii)  Added --help to list all options with an explanatory phrase.
2237       (iii) Added -r, --recursive to recurse into sub-directories.
2238       (iv)  Added -f, --file to read patterns from a file.
2239    
2240    6. pcre_exec() was referring to its "code" argument before testing that
2241    argument for NULL (and giving an error if it was NULL).
2242    
2243    7. Upgraded Makefile.in to allow for compiling in a different directory from
2244    the source directory.
2245    
2246    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2247    options bits, the pointer it was passed was to an int instead of to an unsigned
2248    long int. This mattered only on 64-bit systems.
2249    
2250    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2251    generated) instead of pcre.in, which it its source. Also made the same change
2252    in several of the .c files.
2253    
2254    10. A new release of gcc defines printf() as a macro, which broke pcretest
2255    because it had an ifdef in the middle of a string argument for printf(). Fixed
2256    by using separate calls to printf().
2257    
2258    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2259    script, to force use of CR or LF instead of \n in the source. On non-Unix
2260    systems, the value can be set in config.h.
2261    
2262    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2263    absolute limit. Changed the text of the error message to make this clear, and
2264    likewise updated the man page.
2265    
2266    13. The limit of 99 on the number of capturing subpatterns has been removed.
2267    The new limit is 65535, which I hope will not be a "real" limit.
2268    
2269    
2270    Version 3.4 22-Aug-00
2271    ---------------------
2272    
2273    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2274    
2275    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2276    
2277    
2278    Version 3.3 01-Aug-00
2279    ---------------------
2280    
2281    1. If an octal character was given, but the value was greater than \377, it
2282    was not getting masked to the least significant bits, as documented. This could
2283    lead to crashes in some systems.
2284    
2285    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2286    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2287    
2288    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2289    These just pass their arguments on to (pcre_free)(), but they are provided
2290    because some uses of PCRE bind it to non-C systems that can call its functions,
2291    but cannot call free() or pcre_free() directly.
2292    
2293    4. Add "make test" as a synonym for "make check". Corrected some comments in
2294    the Makefile.
2295    
2296    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2297    Makefile.
2298    
2299    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2300    command called pgrep for grepping around the active processes.
2301    
2302    7. Added the beginnings of support for UTF-8 character strings.
2303    
2304    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2305    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2306    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2307    out for the ar command.)
2308    
2309    
2310  Version 3.2 12-May-00  Version 3.2 12-May-00
2311  ---------------------  ---------------------

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