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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 09-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    
142    Version 7.2 19-Jun-07
143    ---------------------
144    
145     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
146        which is apparently normally available under Windows.
147    
148     2. Re-jig the pcregrep tests with different newline settings in an attempt
149        to make them independent of the local environment's newline setting.
150    
151     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
152    
153     4. Some of the "internals" tests were previously cut out when the link size
154        was not 2, because the output contained actual offsets. The recent new
155        "Z" feature of pcretest means that these can be cut out, making the tests
156        usable with all link sizes.
157    
158     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
159        stack recursion. This gives a massive performance boost under BSD, but just
160        a small improvement under Linux. However, it saves one field in the frame
161        in all cases.
162    
163     6. Added more features from the forthcoming Perl 5.10:
164    
165        (a) (?-n) (where n is a string of digits) is a relative subroutine or
166            recursion call. It refers to the nth most recently opened parentheses.
167    
168        (b) (?+n) is also a relative subroutine call; it refers to the nth next
169            to be opened parentheses.
170    
171        (c) Conditions that refer to capturing parentheses can be specified
172            relatively, for example, (?(-2)... or (?(+3)...
173    
174        (d) \K resets the start of the current match so that everything before
175            is not part of it.
176    
177        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
178    
179        (f) \g{name} is another synonym - part of Perl 5.10's unification of
180            reference syntax.
181    
182        (g) (?| introduces a group in which the numbering of parentheses in each
183            alternative starts with the same number.
184    
185        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
186    
187     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
188        PCRE_INFO_JCHANGED.
189    
190     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
191        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
192        for detecting groups that can match an empty string.
193    
194     9. A pattern with a very large number of alternatives (more than several
195        hundred) was running out of internal workspace during the pre-compile
196        phase, where pcre_compile() figures out how much memory will be needed. A
197        bit of new cunning has reduced the workspace needed for groups with
198        alternatives. The 1000-alternative test pattern now uses 12 bytes of
199        workspace instead of running out of the 4096 that are available.
200    
201    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
202    
203    11. Applied patch from Google to remove an optimization that didn't quite work.
204        The report of the bug said:
205    
206          pcrecpp::RE("a*").FullMatch("aaa") matches, while
207          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
208          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
209    
210    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
211        it matched the wrong number of bytes.
212    
213    
214    Version 7.1 24-Apr-07
215    ---------------------
216    
217     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
218        that is more "standard", making use of automake and other Autotools. There
219        is some re-arrangement of the files and adjustment of comments consequent
220        on this.
221    
222     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
223        for recursive directory scanning broke on some systems because the files
224        are not scanned in any specific order and on different systems the order
225        was different. A call to "sort" has been inserted into RunGrepTest for the
226        approprate test as a short-term fix. In the longer term there may be an
227        alternative.
228    
229     3. I had an email from Eric Raymond about problems translating some of PCRE's
230        man pages to HTML (despite the fact that I distribute HTML pages, some
231        people do their own conversions for various reasons). The problems
232        concerned the use of low-level troff macros .br and .in. I have therefore
233        removed all such uses from the man pages (some were redundant, some could
234        be replaced by .nf/.fi pairs). The 132html script that I use to generate
235        HTML has been updated to handle .nf/.fi and to complain if it encounters
236        .br or .in.
237    
238     4. Updated comments in configure.ac that get placed in config.h.in and also
239        arranged for config.h to be included in the distribution, with the name
240        config.h.generic, for the benefit of those who have to compile without
241        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
242    
243     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
244        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
245        makevp.bat for the current PCRE, using the additional files
246        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
247    
248     6. A Windows user reported a minor discrepancy with test 2, which turned out
249        to be caused by a trailing space on an input line that had got lost in his
250        copy. The trailing space was an accident, so I've just removed it.
251    
252     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
253        that is needed.
254    
255     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
256        as "const" (a) because they are and (b) because it helps the PHP
257        maintainers who have recently made a script to detect big data structures
258        in the php code that should be moved to the .rodata section. I remembered
259        to update Builducptable as well, so it won't revert if ucptable.h is ever
260        re-created.
261    
262     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
263        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
264        order to be able to cut out the UTF-8 tables in the latter when UTF-8
265        support is not required. This saves 1.5-2K of code, which is important in
266        some applications.
267    
268        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
269        so as not to refer to the tables, even though these functions will never be
270        called when UTF-8 support is disabled. Otherwise there are problems with a
271        shared library.
272    
273    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
274    
275        (a) It was defining its arguments as char * instead of void *.
276    
277        (b) It was assuming that all moves were upwards in memory; this was true
278            a long time ago when I wrote it, but is no longer the case.
279    
280        The emulated memove() is provided for those environments that have neither
281        memmove() nor bcopy(). I didn't think anyone used it these days, but that
282        is clearly not the case, as these two bugs were recently reported.
283    
284    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
285        and Detrail to create the HTML documentation, the .txt form of the man
286        pages, and it removes trailing spaces from listed files. It also creates
287        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
288        case, it wraps all the #defines with #ifndefs. This script should be run
289        before "make dist".
290    
291    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
292        with Unicode property support.
293    
294        (a) For a maximizing quantifier, if the two different cases of the
295            character were of different lengths in their UTF-8 codings (there are
296            some cases like this - I found 11), and the matching function had to
297            back up over a mixture of the two cases, it incorrectly assumed they
298            were both the same length.
299    
300        (b) When PCRE was configured to use the heap rather than the stack for
301            recursion during matching, it was not correctly preserving the data for
302            the other case of a UTF-8 character when checking ahead for a match
303            while processing a minimizing repeat. If the check also involved
304            matching a wide character, but failed, corruption could cause an
305            erroneous result when trying to check for a repeat of the original
306            character.
307    
308    13. Some tidying changes to the testing mechanism:
309    
310        (a) The RunTest script now detects the internal link size and whether there
311            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
312            values substituted by "configure". (The RunGrepTest script already did
313            this for UTF-8.) The configure.ac script no longer substitutes the
314            relevant variables.
315    
316        (b) The debugging options /B and /D in pcretest show the compiled bytecode
317            with length and offset values. This means that the output is different
318            for different internal link sizes. Test 2 is skipped for link sizes
319            other than 2 because of this, bypassing the problem. Unfortunately,
320            there was also a test in test 3 (the locale tests) that used /B and
321            failed for link sizes other than 2. Rather than cut the whole test out,
322            I have added a new /Z option to pcretest that replaces the length and
323            offset values with spaces. This is now used to make test 3 independent
324            of link size. (Test 2 will be tidied up later.)
325    
326    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
327        segmentation fault instead of returning the appropriate error message.
328    
329    15. In multiline mode when the newline sequence was set to "any", the pattern
330        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
331        This doesn't seem right; it now treats the CRLF combination as the line
332        ending, and so does not match in that case. It's only a pattern such as ^$
333        that would hit this one: something like ^ABC$ would have failed after \r
334        and then tried again after \r\n.
335    
336    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
337        in an attempt to make files that differ only in their line terminators
338        compare equal. This works on Linux.
339    
340    17. Under certain error circumstances pcregrep might try to free random memory
341        as it exited. This is now fixed, thanks to valgrind.
342    
343    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
344        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
345        was because its rules for how to advance for /g after matching an empty
346        string at the end of a line did not allow for this case. They now check for
347        it specially.
348    
349    20. pcretest is supposed to handle patterns and data of any length, by
350        extending its buffers when necessary. It was getting this wrong when the
351        buffer for a data line had to be extended.
352    
353    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
354        CRLF as a newline sequence.
355    
356    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
357        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
358        I have nevertheless tidied it up.
359    
360    23. Added some casts to kill warnings from HP-UX ia64 compiler.
361    
362    24. Added a man page for pcre-config.
363    
364    
365    Version 7.0 19-Dec-06
366    ---------------------
367    
368     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
369        moving to gcc 4.1.1.
370    
371     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
372        sys/time.h, which is documented as needed for this function. It doesn't
373        seem to matter on Linux, but it showed up on some releases of OS X.
374    
375     3. It seems that there are systems where bytes whose values are greater than
376        127 match isprint() in the "C" locale. The "C" locale should be the
377        default when a C program starts up. In most systems, only ASCII printing
378        characters match isprint(). This difference caused the output from pcretest
379        to vary, making some of the tests fail. I have changed pcretest so that:
380    
381        (a) When it is outputting text in the compiled version of a pattern, bytes
382            other than 32-126 are always shown as hex escapes.
383    
384        (b) When it is outputting text that is a matched part of a subject string,
385            it does the same, unless a different locale has been set for the match
386            (using the /L modifier). In this case, it uses isprint() to decide.
387    
388     4. Fixed a major bug that caused incorrect computation of the amount of memory
389        required for a compiled pattern when options that changed within the
390        pattern affected the logic of the preliminary scan that determines the
391        length. The relevant options are -x, and -i in UTF-8 mode. The result was
392        that the computed length was too small. The symptoms of this bug were
393        either the PCRE error "internal error: code overflow" from pcre_compile(),
394        or a glibc crash with a message such as "pcretest: free(): invalid next
395        size (fast)". Examples of patterns that provoked this bug (shown in
396        pcretest format) are:
397    
398          /(?-x: )/x
399          /(?x)(?-x: \s*#\s*)/
400          /((?i)[\x{c0}])/8
401          /(?i:[\x{c0}])/8
402    
403        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
404        is now done differently.
405    
406     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
407        wrapper classes; (b) implement a new function in the C++ scanner that is
408        more efficient than the old way of doing things because it avoids levels of
409        recursion in the regex matching; (c) add a paragraph to the documentation
410        for the FullMatch() function.
411    
412     6. The escape sequence \n was being treated as whatever was defined as
413        "newline". Not only was this contrary to the documentation, which states
414        that \n is character 10 (hex 0A), but it also went horribly wrong when
415        "newline" was defined as CRLF. This has been fixed.
416    
417     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
418        was being set to -1 for the "end of line" case (supposedly a value that no
419        character can have). Though this value is never used (the check for end of
420        line is "zero bytes in current character"), it caused compiler complaints.
421        I've changed it to 0xffffffff.
422    
423     8. In pcre_version.c, the version string was being built by a sequence of
424        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
425        string (as it is for production releases) called a macro with an empty
426        argument. The C standard says the result of this is undefined. The gcc
427        compiler treats it as an empty string (which was what was wanted) but it is
428        reported that Visual C gives an error. The source has been hacked around to
429        avoid this problem.
430    
431     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
432        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
433        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
434        of them did).
435    
436    10. Originally, pcretest opened its input and output without "b"; then I was
437        told that "b" was needed in some environments, so it was added for release
438        5.0 to both the input and output. (It makes no difference on Unix-like
439        systems.) Later I was told that it is wrong for the input on Windows. I've
440        now abstracted the modes into two macros, to make it easier to fiddle with
441        them, and removed "b" from the input mode under Windows.
442    
443    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
444    
445    12. Added -help and --help to pcretest as an official way of being reminded
446        of the options.
447    
448    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
449        and pcrecpp.cc because they annoy compilers at high warning levels.
450    
451    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
452    
453    15. Fixed an occurrence of == in configure.ac that should have been = (shell
454        scripts are not C programs :-) and which was not noticed because it works
455        on Linux.
456    
457    16. pcretest is supposed to handle any length of pattern and data line (as one
458        line or as a continued sequence of lines) by extending its input buffer if
459        necessary. This feature was broken for very long pattern lines, leading to
460        a string of junk being passed to pcre_compile() if the pattern was longer
461        than about 50K.
462    
463    17. I have done a major re-factoring of the way pcre_compile() computes the
464        amount of memory needed for a compiled pattern. Previously, there was code
465        that made a preliminary scan of the pattern in order to do this. That was
466        OK when PCRE was new, but as the facilities have expanded, it has become
467        harder and harder to keep it in step with the real compile phase, and there
468        have been a number of bugs (see for example, 4 above). I have now found a
469        cunning way of running the real compile function in a "fake" mode that
470        enables it to compute how much memory it would need, while actually only
471        ever using a few hundred bytes of working memory and without too many
472        tests of the mode. This should make future maintenance and development
473        easier. A side effect of this work is that the limit of 200 on the nesting
474        depth of parentheses has been removed (though this was never a serious
475        limitation, I suspect). However, there is a downside: pcre_compile() now
476        runs more slowly than before (30% or more, depending on the pattern). I
477        hope this isn't a big issue. There is no effect on runtime performance.
478    
479    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
480        newline (only possible for the last line of a file) and it was a
481        pattern that set a locale (followed by /Lsomething), pcretest crashed.
482    
483    19. Added additional timing features to pcretest. (1) The -tm option now times
484        matching only, not compiling. (2) Both -t and -tm can be followed, as a
485        separate command line item, by a number that specifies the number of
486        repeats to use when timing. The default is 50000; this gives better
487        precision, but takes uncomfortably long for very large patterns.
488    
489    20. Extended pcre_study() to be more clever in cases where a branch of a
490        subpattern has no definite first character. For example, (a*|b*)[cd] would
491        previously give no result from pcre_study(). Now it recognizes that the
492        first character must be a, b, c, or d.
493    
494    21. There was an incorrect error "recursive call could loop indefinitely" if
495        a subpattern (or the entire pattern) that was being tested for matching an
496        empty string contained only one non-empty item after a nested subpattern.
497        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
498        incorrectly, because the \d was being skipped in the check.
499    
500    22. The pcretest program now has a new pattern option /B and a command line
501        option -b, which is equivalent to adding /B to every pattern. This causes
502        it to show the compiled bytecode, without the additional information that
503        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
504        is the same as /B/I).
505    
506    23. A new optimization is now able automatically to treat some sequences such
507        as a*b as a*+b. More specifically, if something simple (such as a character
508        or a simple class like \d) has an unlimited quantifier, and is followed by
509        something that cannot possibly match the quantified thing, the quantifier
510        is automatically "possessified".
511    
512    24. A recursive reference to a subpattern whose number was greater than 39
513        went wrong under certain circumstances in UTF-8 mode. This bug could also
514        have affected the operation of pcre_study().
515    
516    25. Realized that a little bit of performance could be had by replacing
517        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
518    
519    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
520    
521    27. Possessive quantifiers such as a++ were previously implemented by turning
522        them into atomic groups such as ($>a+). Now they have their own opcodes,
523        which improves performance. This includes the automatically created ones
524        from 23 above.
525    
526    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
527        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
528        the first matched character to be a colon. This applied both to named and
529        numbered groups.
530    
531    29. The ucpinternal.h header file was missing its idempotency #ifdef.
532    
533    30. I was sent a "project" file called libpcre.a.dev which I understand makes
534        building PCRE on Windows easier, so I have included it in the distribution.
535    
536    31. There is now a check in pcretest against a ridiculously large number being
537        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
538        loop, the loop is abandoned.
539    
540    32. Forward references to subpatterns in conditions such as (?(2)...) where
541        subpattern 2 is defined later cause pcre_compile() to search forwards in
542        the pattern for the relevant set of parentheses. This search went wrong
543        when there were unescaped parentheses in a character class, parentheses
544        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
545    
546    33. "Subroutine" calls and backreferences were previously restricted to
547        referencing subpatterns earlier in the regex. This restriction has now
548        been removed.
549    
550    34. Added a number of extra features that are going to be in Perl 5.10. On the
551        whole, these are just syntactic alternatives for features that PCRE had
552        previously implemented using the Python syntax or my own invention. The
553        other formats are all retained for compatibility.
554    
555        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
556            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
557            also .NET compatible.
558    
559        (b) A recursion or subroutine call to a named group can now be defined as
560            (?&name) as well as (?P>name).
561    
562        (c) A backreference to a named group can now be defined as \k<name> or
563            \k'name' as well as (?P=name). The new forms, as well as being in Perl
564            5.10, are also .NET compatible.
565    
566        (d) A conditional reference to a named group can now use the syntax
567            (?(<name>) or (?('name') as well as (?(name).
568    
569        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
570            groups (named and numbered) that are never evaluated inline, but can be
571            called as "subroutines" from elsewhere. In effect, the DEFINE condition
572            is always false. There may be only one alternative in such a group.
573    
574        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
575            as the simple (?(R). The condition is true only if the most recent
576            recursion is that of the given number or name. It does not search out
577            through the entire recursion stack.
578    
579        (g) The escape \gN or \g{N} has been added, where N is a positive or
580            negative number, specifying an absolute or relative reference.
581    
582    35. Tidied to get rid of some further signed/unsigned compiler warnings and
583        some "unreachable code" warnings.
584    
585    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
586        things, this adds five new scripts.
587    
588    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
589        There were also incompatibilities regarding the handling of \Q..\E inside
590        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
591        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
592    
593    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
594        matches an empty string, and forcibly breaks the loop. There were bugs in
595        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
596        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
597        separate and independent bugs (that affected different cases) have been
598        fixed.
599    
600    39. Refactored the code to abolish the use of different opcodes for small
601        capturing bracket numbers. This is a tidy that I avoided doing when I
602        removed the limit on the number of capturing brackets for 3.5 back in 2001.
603        The new approach is not only tidier, it makes it possible to reduce the
604        memory needed to fix the previous bug (38).
605    
606    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
607        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
608        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
609        mode.
610    
611    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
612        report.
613    
614    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
615        copy construction and assignment in the C++ wrapper.
616    
617    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
618        couple of bugs that could have given wrong results in the "--newline=crlf"
619        case.
620    
621    44. Added a number of casts and did some reorganization of signed/unsigned int
622        variables following suggestions from Dair Grant. Also renamed the variable
623        "this" as "item" because it is a C++ keyword.
624    
625    45. Arranged for dftables to add
626    
627          #include "pcre_internal.h"
628    
629        to pcre_chartables.c because without it, gcc 4.x may remove the array
630        definition from the final binary if PCRE is built into a static library and
631        dead code stripping is activated.
632    
633    46. For an unanchored pattern, if a match attempt fails at the start of a
634        newline sequence, and the newline setting is CRLF or ANY, and the next two
635        characters are CRLF, advance by two characters instead of one.
636    
637    
638    Version 6.7 04-Jul-06
639    ---------------------
640    
641     1. In order to handle tests when input lines are enormously long, pcretest has
642        been re-factored so that it automatically extends its buffers when
643        necessary. The code is crude, but this _is_ just a test program. The
644        default size has been increased from 32K to 50K.
645    
646     2. The code in pcre_study() was using the value of the re argument before
647        testing it for NULL. (Of course, in any sensible call of the function, it
648        won't be NULL.)
649    
650     3. The memmove() emulation function in pcre_internal.h, which is used on
651        systems that lack both memmove() and bcopy() - that is, hardly ever -
652        was missing a "static" storage class specifier.
653    
654     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
655        containing an extended class (one that cannot be represented by a bitmap
656        because it contains high-valued characters or Unicode property items, e.g.
657        [\pZ]). Almost always one would set UTF-8 mode when processing such a
658        pattern, but PCRE should not loop if you do not (it no longer does).
659        [Detail: two cases were found: (a) a repeated subpattern containing an
660        extended class; (b) a recursive reference to a subpattern that followed a
661        previous extended class. It wasn't skipping over the extended class
662        correctly when UTF-8 mode was not set.]
663    
664     5. A negated single-character class was not being recognized as fixed-length
665        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
666        compile error "lookbehind assertion is not fixed length".
667    
668     6. The RunPerlTest auxiliary script was showing an unexpected difference
669        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
670        write a Perl script that can interpret lines of an input file either as
671        byte characters or as UTF-8, which is what "perltest" was being required to
672        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
673        can't do is switch easily at run time between having the "use utf8;" pragma
674        or not. In the end, I fudged it by using the RunPerlTest script to insert
675        "use utf8;" explicitly for the UTF-8 tests.
676    
677     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
678        the end of the subject string, contrary to the documentation and to what
679        Perl does. This was true of both matching functions. Now it matches only at
680        the start of the subject and immediately after *internal* newlines.
681    
682     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
683        a pointer to an int instead of a pointer to an unsigned long int. This
684        caused problems on 64-bit systems.
685    
686     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
687        instance of the 'standard' template library not being so standard".
688    
689    10. There was no check on the number of named subpatterns nor the maximum
690        length of a subpattern name. The product of these values is used to compute
691        the size of the memory block for a compiled pattern. By supplying a very
692        long subpattern name and a large number of named subpatterns, the size
693        computation could be caused to overflow. This is now prevented by limiting
694        the length of names to 32 characters, and the number of named subpatterns
695        to 10,000.
696    
697    11. Subpatterns that are repeated with specific counts have to be replicated in
698        the compiled pattern. The size of memory for this was computed from the
699        length of the subpattern and the repeat count. The latter is limited to
700        65535, but there was no limit on the former, meaning that integer overflow
701        could in principle occur. The compiled length of a repeated subpattern is
702        now limited to 30,000 bytes in order to prevent this.
703    
704    12. Added the optional facility to have named substrings with the same name.
705    
706    13. Added the ability to use a named substring as a condition, using the
707        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
708        are numbers (not recommended). Forward references are permitted.
709    
710    14. Added forward references in named backreferences (if you see what I mean).
711    
712    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
713        pattern could run off the end of the subject. For example, the pattern
714        "(?s)(.{1,5})"8 did this with the subject "ab".
715    
716    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
717        PCRE_CASELESS was set when matching characters that were quantified with ?
718        or *.
719    
720    17. A character class other than a single negated character that had a minimum
721        but no maximum quantifier - for example [ab]{6,} - was not handled
722        correctly by pce_dfa_exec(). It would match only one character.
723    
724    18. A valid (though odd) pattern that looked like a POSIX character
725        class but used an invalid character after [ (for example [[,abc,]]) caused
726        pcre_compile() to give the error "Failed: internal error: code overflow" or
727        in some cases to crash with a glibc free() error. This could even happen if
728        the pattern terminated after [[ but there just happened to be a sequence of
729        letters, a binary zero, and a closing ] in the memory that followed.
730    
731    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
732        over the years. Originally (before any Unicode support), just the bottom 8
733        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
734        output from "man perlunicode" includes this:
735    
736          The regular expression compiler produces polymorphic opcodes.  That
737          is, the pattern adapts to the data and automatically switches to
738          the Unicode character scheme when presented with Unicode data--or
739          instead uses a traditional byte scheme when presented with byte
740          data.
741    
742        Sadly, a wide octal escape does not cause a switch, and in a string with
743        no other multibyte characters, these octal escapes are treated as before.
744        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
745        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
746        Unicode string.
747    
748        I have not perpetrated such confusion in PCRE. Up till now, it took just
749        the bottom 8 bits, as in old Perl. I have now made octal escapes with
750        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
751        translate to the appropriate multibyte character.
752    
753    29. Applied some refactoring to reduce the number of warnings from Microsoft
754        and Borland compilers. This has included removing the fudge introduced
755        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
756        a warning about an unused variable.
757    
758    21. PCRE has not included VT (character 0x0b) in the set of whitespace
759        characters since release 4.0, because Perl (from release 5.004) does not.
760        [Or at least, is documented not to: some releases seem to be in conflict
761        with the documentation.] However, when a pattern was studied with
762        pcre_study() and all its branches started with \s, PCRE still included VT
763        as a possible starting character. Of course, this did no harm; it just
764        caused an unnecessary match attempt.
765    
766    22. Removed a now-redundant internal flag bit that recorded the fact that case
767        dependency changed within the pattern. This was once needed for "required
768        byte" processing, but is no longer used. This recovers a now-scarce options
769        bit. Also moved the least significant internal flag bit to the most-
770        significant bit of the word, which was not previously used (hangover from
771        the days when it was an int rather than a uint) to free up another bit for
772        the future.
773    
774    23. Added support for CRLF line endings as well as CR and LF. As well as the
775        default being selectable at build time, it can now be changed at runtime
776        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
777        specify that it is scanning data with non-default line endings.
778    
779    24. Changed the definition of CXXLINK to make it agree with the definition of
780        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
781    
782    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
783        recursions. This makes a big different to stack usage for some patterns.
784    
785    26. If a subpattern containing a named recursion or subroutine reference such
786        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
787        the space required for the compiled pattern went wrong and gave too small a
788        value. Depending on the environment, this could lead to "Failed: internal
789        error: code overflow at offset 49" or "glibc detected double free or
790        corruption" errors.
791    
792    27. Applied patches from Google (a) to support the new newline modes and (b) to
793        advance over multibyte UTF-8 characters in GlobalReplace.
794    
795    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
796        difference for some implementation of PCRE in some Windows version.
797    
798    29. Added some extra testing facilities to pcretest:
799    
800        \q<number>   in a data line sets the "match limit" value
801        \Q<number>   in a data line sets the "match recursion limt" value
802        -S <number>  sets the stack size, where <number> is in megabytes
803    
804        The -S option isn't available for Windows.
805    
806    
807    Version 6.6 06-Feb-06
808    ---------------------
809    
810     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
811        in pcreposix.h. I have copied the definition from pcre.h.
812    
813     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
814        because pcre.h is no longer a built file.
815    
816     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
817        not normally included in the compiled code.
818    
819    
820    Version 6.5 01-Feb-06
821    ---------------------
822    
823     1. When using the partial match feature with pcre_dfa_exec(), it was not
824        anchoring the second and subsequent partial matches at the new starting
825        point. This could lead to incorrect results. For example, with the pattern
826        /1234/, partially matching against "123" and then "a4" gave a match.
827    
828     2. Changes to pcregrep:
829    
830        (a) All non-match returns from pcre_exec() were being treated as failures
831            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
832            error message is output. Some extra information is given for the
833            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
834            probably the only errors that are likely to be caused by users (by
835            specifying a regex that has nested indefinite repeats, for instance).
836            If there are more than 20 of these errors, pcregrep is abandoned.
837    
838        (b) A binary zero was treated as data while matching, but terminated the
839            output line if it was written out. This has been fixed: binary zeroes
840            are now no different to any other data bytes.
841    
842        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
843            used to set a locale for matching. The --locale=xxxx long option has
844            been added (no short equivalent) to specify a locale explicitly on the
845            pcregrep command, overriding the environment variables.
846    
847        (d) When -B was used with -n, some line numbers in the output were one less
848            than they should have been.
849    
850        (e) Added the -o (--only-matching) option.
851    
852        (f) If -A or -C was used with -c (count only), some lines of context were
853            accidentally printed for the final match.
854    
855        (g) Added the -H (--with-filename) option.
856    
857        (h) The combination of options -rh failed to suppress file names for files
858            that were found from directory arguments.
859    
860        (i) Added the -D (--devices) and -d (--directories) options.
861    
862        (j) Added the -F (--fixed-strings) option.
863    
864        (k) Allow "-" to be used as a file name for -f as well as for a data file.
865    
866        (l) Added the --colo(u)r option.
867    
868        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
869            is not present by default.
870    
871     3. A nasty bug was discovered in the handling of recursive patterns, that is,
872        items such as (?R) or (?1), when the recursion could match a number of
873        alternatives. If it matched one of the alternatives, but subsequently,
874        outside the recursion, there was a failure, the code tried to back up into
875        the recursion. However, because of the way PCRE is implemented, this is not
876        possible, and the result was an incorrect result from the match.
877    
878        In order to prevent this happening, the specification of recursion has
879        been changed so that all such subpatterns are automatically treated as
880        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
881    
882     4. I had overlooked the fact that, in some locales, there are characters for
883        which isalpha() is true but neither isupper() nor islower() are true. In
884        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
885        and ordfeminine) are like this. This affected the treatment of \w and \W
886        when they appeared in character classes, but not when they appeared outside
887        a character class. The bit map for "word" characters is now created
888        separately from the results of isalnum() instead of just taking it from the
889        upper, lower, and digit maps. (Plus the underscore character, of course.)
890    
891     5. The above bug also affected the handling of POSIX character classes such as
892        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
893        permanent tables. Instead, the bit maps for such a class were previously
894        created as the appropriate unions of the upper, lower, and digit bitmaps.
895        Now they are created by subtraction from the [[:word:]] class, which has
896        its own bitmap.
897    
898     6. The [[:blank:]] character class matches horizontal, but not vertical space.
899        It is created by subtracting the vertical space characters (\x09, \x0a,
900        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
901        subtraction was done in the overall bitmap for a character class, meaning
902        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
903        be recognized. This bug has been fixed.
904    
905     7. Patches from the folks at Google:
906    
907          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
908          real life, but is still worth protecting against".
909    
910          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
911          regular expressions".
912    
913          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
914          have it.
915    
916          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
917          "configure" and the latter not, in order to fix a problem somebody had
918          with compiling the Arg class on HP-UX.
919    
920          (e) Improve the error-handling of the C++ wrapper a little bit.
921    
922          (f) New tests for checking recursion limiting.
923    
924     8. The pcre_memmove() function, which is used only if the environment does not
925        have a standard memmove() function (and is therefore rarely compiled),
926        contained two bugs: (a) use of int instead of size_t, and (b) it was not
927        returning a result (though PCRE never actually uses the result).
928    
929     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
930        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
931        returned instead of calling malloc() with an overflowing number that would
932        most likely cause subsequent chaos.
933    
934    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
935    
936    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
937        with this option is matched, the nmatch and pmatch options of regexec() are
938        ignored.
939    
940    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
941        provided in case anyone wants to the the POSIX interface with UTF-8
942        strings.
943    
944    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
945        C++ linking (needed for some HP-UX environments).
946    
947    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
948        (unused parameter) and in the pcre_printint() function (omitted "default"
949        switch label when the default is to do nothing).
950    
951    15. Added some code to make it possible, when PCRE is compiled as a C++
952        library, to replace subject pointers for pcre_exec() with a smart pointer
953        class, thus making it possible to process discontinuous strings.
954    
955    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
956        much the same function. They were added by different people who were trying
957        to make PCRE easy to compile on non-Unix systems. It has been suggested
958        that PCRE_EXPORT be abolished now that there is more automatic apparatus
959        for compiling on Windows systems. I have therefore replaced it with
960        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
961        defaults to "extern" for C or "extern C" for C++, which works fine on
962        Unix-like systems. It is now possible to override the value of PCRE_DATA_
963        SCOPE with something explicit in config.h. In addition:
964    
965        (a) pcreposix.h still had just "extern" instead of either of these macros;
966            I have replaced it with PCRE_DATA_SCOPE.
967    
968        (b) Functions such as _pcre_xclass(), which are internal to the library,
969            but external in the C sense, all had PCRE_EXPORT in their definitions.
970            This is apparently wrong for the Windows case, so I have removed it.
971            (It makes no difference on Unix-like systems.)
972    
973    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
974        of recursive calls to match(). This is different to MATCH_LIMIT because
975        that limits the total number of calls to match(), not all of which increase
976        the depth of recursion. Limiting the recursion depth limits the amount of
977        stack (or heap if NO_RECURSE is set) that is used. The default can be set
978        when PCRE is compiled, and changed at run time. A patch from Google adds
979        this functionality to the C++ interface.
980    
981    18. Changes to the handling of Unicode character properties:
982    
983        (a) Updated the table to Unicode 4.1.0.
984    
985        (b) Recognize characters that are not in the table as "Cn" (undefined).
986    
987        (c) I revised the way the table is implemented to a much improved format
988            which includes recognition of ranges. It now supports the ranges that
989            are defined in UnicodeData.txt, and it also amalgamates other
990            characters into ranges. This has reduced the number of entries in the
991            table from around 16,000 to around 3,000, thus reducing its size
992            considerably. I realized I did not need to use a tree structure after
993            all - a binary chop search is just as efficient. Having reduced the
994            number of entries, I extended their size from 6 bytes to 8 bytes to
995            allow for more data.
996    
997        (d) Added support for Unicode script names via properties such as \p{Han}.
998    
999    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1000        matching that character.
1001    
1002    20. When matching a repeated Unicode property with a minimum greater than zero,
1003        (for example \pL{2,}), PCRE could look past the end of the subject if it
1004        reached it while seeking the minimum number of characters. This could
1005        happen only if some of the characters were more than one byte long, because
1006        there is a check for at least the minimum number of bytes.
1007    
1008    21. Refactored the implementation of \p and \P so as to be more general, to
1009        allow for more different types of property in future. This has changed the
1010        compiled form incompatibly. Anybody with saved compiled patterns that use
1011        \p or \P will have to recompile them.
1012    
1013    22. Added "Any" and "L&" to the supported property types.
1014    
1015    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1016        but give a compile time error if the value is greater than 0xff.
1017    
1018    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1019        accidentally not being installed or uninstalled.
1020    
1021    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1022        made were to insert the current release number. This seemed silly, because
1023        it made things harder for people building PCRE on systems that don't run
1024        "configure". I have turned pcre.h into a distributed file, no longer built
1025        by "configure", with the version identification directly included. There is
1026        no longer a pcre.h.in file.
1027    
1028        However, this change necessitated a change to the pcre-config script as
1029        well. It is built from pcre-config.in, and one of the substitutions was the
1030        release number. I have updated configure.ac so that ./configure now finds
1031        the release number by grepping pcre.h.
1032    
1033    26. Added the ability to run the tests under valgrind.
1034    
1035    
1036    Version 6.4 05-Sep-05
1037    ---------------------
1038    
1039     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1040        "--" to be printed when multiple files were scanned, even when none of the
1041        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1042        consider it to be a bug, and have restored the previous behaviour.
1043    
1044     2. A couple of code tidies to get rid of compiler warnings.
1045    
1046     3. The pcretest program used to cheat by referring to symbols in the library
1047        whose names begin with _pcre_. These are internal symbols that are not
1048        really supposed to be visible externally, and in some environments it is
1049        possible to suppress them. The cheating is now confined to including
1050        certain files from the library's source, which is a bit cleaner.
1051    
1052     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1053        file's purpose clearer.
1054    
1055     5. Reorganized pcre_ucp_findchar().
1056    
1057    
1058    Version 6.3 15-Aug-05
1059    ---------------------
1060    
1061     1. The file libpcre.pc.in did not have general read permission in the tarball.
1062    
1063     2. There were some problems when building without C++ support:
1064    
1065        (a) If C++ support was not built, "make install" and "make test" still
1066            tried to test it.
1067    
1068        (b) There were problems when the value of CXX was explicitly set. Some
1069            changes have been made to try to fix these, and ...
1070    
1071        (c) --disable-cpp can now be used to explicitly disable C++ support.
1072    
1073        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1074            backslash in a target when C++ was disabled. This confuses some
1075            versions of "make", apparently. Using an intermediate variable solves
1076            this. (Same for CPP_LOBJ.)
1077    
1078     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1079        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1080        necessary on certain architectures.
1081    
1082     4. Added a setting of -export-symbols-regex to the link command to remove
1083        those symbols that are exported in the C sense, but actually are local
1084        within the library, and not documented. Their names all begin with
1085        "_pcre_". This is not a perfect job, because (a) we have to except some
1086        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1087        available (and never for static libraries). I have made a note to try to
1088        find a way round (a) in the future.
1089    
1090    
1091    Version 6.2 01-Aug-05
1092    ---------------------
1093    
1094     1. There was no test for integer overflow of quantifier values. A construction
1095        such as {1111111111111111} would give undefined results. What is worse, if
1096        a minimum quantifier for a parenthesized subpattern overflowed and became
1097        negative, the calculation of the memory size went wrong. This could have
1098        led to memory overwriting.
1099    
1100     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1101    
1102     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1103        operating environments where this matters.
1104    
1105     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1106        PCRE options from within the C++ wrapper.
1107    
1108     5. Named capturing subpatterns were not being correctly counted when a pattern
1109        was compiled. This caused two problems: (a) If there were more than 100
1110        such subpatterns, the calculation of the memory needed for the whole
1111        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1112        back references of the form \12, where the number was greater than 9, were
1113        not recognized as back references, even though there were sufficient
1114        previous subpatterns.
1115    
1116     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1117        versions of gcc, e.g. 2.95.4.
1118    
1119    
1120    Version 6.1 21-Jun-05
1121    ---------------------
1122    
1123     1. There was one reference to the variable "posix" in pcretest.c that was not
1124        surrounded by "#if !defined NOPOSIX".
1125    
1126     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1127        the cross-check on the old pcre_info() function, for the benefit of the
1128        cut-down version of PCRE that is currently imported into Exim.
1129    
1130     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1131        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1132        patterns that start (?i) but I don't think that matters. The use of (?i) is
1133        just an example; this all applies to the other options as well.
1134    
1135     4. Since libtool seems to echo the compile commands it is issuing, the output
1136        from "make" can be reduced a bit by putting "@" in front of each libtool
1137        compile command.
1138    
1139     5. Patch from the folks at Google for configure.in to be a bit more thorough
1140        in checking for a suitable C++ installation before trying to compile the
1141        C++ stuff. This should fix a reported problem when a compiler was present,
1142        but no suitable headers.
1143    
1144     6. The man pages all had just "PCRE" as their title. I have changed them to
1145        be the relevant file name. I have also arranged that these names are
1146        retained in the file doc/pcre.txt, which is a concatenation in text format
1147        of all the man pages except the little individual ones for each function.
1148    
1149     7. The NON-UNIX-USE file had not been updated for the different set of source
1150        files that come with release 6. I also added a few comments about the C++
1151        wrapper.
1152    
1153    
1154    Version 6.0 07-Jun-05
1155    ---------------------
1156    
1157     1. Some minor internal re-organization to help with my DFA experiments.
1158    
1159     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1160        didn't matter for the library itself when fully configured, but did matter
1161        when compiling without UCP support, or within Exim, where the ucp files are
1162        not imported.
1163    
1164     3. Refactoring of the library code to split up the various functions into
1165        different source modules. The addition of the new DFA matching code (see
1166        below) to a single monolithic source would have made it really too
1167        unwieldy, quite apart from causing all the code to be include in a
1168        statically linked application, when only some functions are used. This is
1169        relevant even without the DFA addition now that patterns can be compiled in
1170        one application and matched in another.
1171    
1172        The downside of splitting up is that there have to be some external
1173        functions and data tables that are used internally in different modules of
1174        the library but which are not part of the API. These have all had their
1175        names changed to start with "_pcre_" so that they are unlikely to clash
1176        with other external names.
1177    
1178     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1179        a different (DFA) algorithm. Although it is slower than the original
1180        function, it does have some advantages for certain types of matching
1181        problem.
1182    
1183     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1184        including restarting after a partial match.
1185    
1186     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1187        defined when compiling for Windows was sent to me. I have put it into the
1188        code, though I have no means of testing or verifying it.
1189    
1190     7. Added the pcre_refcount() auxiliary function.
1191    
1192     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1193        match before or at the first newline in the subject string. In pcretest,
1194        the /f option on a pattern can be used to set this.
1195    
1196     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1197        would behave wrongly. This has been present in PCRE since release 4.0.
1198    
1199    10. A number of changes to the pcregrep command:
1200    
1201        (a) Refactored how -x works; insert ^(...)$ instead of setting
1202            PCRE_ANCHORED and checking the length, in preparation for adding
1203            something similar for -w.
1204    
1205        (b) Added the -w (match as a word) option.
1206    
1207        (c) Refactored the way lines are read and buffered so as to have more
1208            than one at a time available.
1209    
1210        (d) Implemented a pcregrep test script.
1211    
1212        (e) Added the -M (multiline match) option. This allows patterns to match
1213            over several lines of the subject. The buffering ensures that at least
1214            8K, or the rest of the document (whichever is the shorter) is available
1215            for matching (and similarly the previous 8K for lookbehind assertions).
1216    
1217        (f) Changed the --help output so that it now says
1218    
1219              -w, --word-regex(p)
1220    
1221            instead of two lines, one with "regex" and the other with "regexp"
1222            because that confused at least one person since the short forms are the
1223            same. (This required a bit of code, as the output is generated
1224            automatically from a table. It wasn't just a text change.)
1225    
1226        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1227            option but starts with a hyphen. Could be a pattern or a path name
1228            starting with a hyphen, for instance.
1229    
1230        (h) "-" can be given as a file name to represent stdin.
1231    
1232        (i) When file names are being printed, "(standard input)" is used for
1233            the standard input, for compatibility with GNU grep. Previously
1234            "<stdin>" was used.
1235    
1236        (j) The option --label=xxx can be used to supply a name to be used for
1237            stdin when file names are being printed. There is no short form.
1238    
1239        (k) Re-factored the options decoding logic because we are going to add
1240            two more options that take data. Such options can now be given in four
1241            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1242    
1243        (l) Added the -A, -B, and -C options for requesting that lines of context
1244            around matches be printed.
1245    
1246        (m) Added the -L option to print the names of files that do not contain
1247            any matching lines, that is, the complement of -l.
1248    
1249        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1250            continue to scan other files.
1251    
1252        (o) The -s option was incorrectly implemented. For compatibility with other
1253            greps, it now suppresses the error message for a non-existent or non-
1254            accessible file (but not the return code). There is a new option called
1255            -q that suppresses the output of matching lines, which was what -s was
1256            previously doing.
1257    
1258        (p) Added --include and --exclude options to specify files for inclusion
1259            and exclusion when recursing.
1260    
1261    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1262        Hopefully, it now does.
1263    
1264    12. Missing cast in pcre_study().
1265    
1266    13. Added an "uninstall" target to the makefile.
1267    
1268    14. Replaced "extern" in the function prototypes in Makefile.in with
1269        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1270        world, but is set differently for Windows.
1271    
1272    15. Added a second compiling function called pcre_compile2(). The only
1273        difference is that it has an extra argument, which is a pointer to an
1274        integer error code. When there is a compile-time failure, this is set
1275        non-zero, in addition to the error test pointer being set to point to an
1276        error message. The new argument may be NULL if no error number is required
1277        (but then you may as well call pcre_compile(), which is now just a
1278        wrapper). This facility is provided because some applications need a
1279        numeric error indication, but it has also enabled me to tidy up the way
1280        compile-time errors are handled in the POSIX wrapper.
1281    
1282    16. Added VPATH=.libs to the makefile; this should help when building with one
1283        prefix path and installing with another. (Or so I'm told by someone who
1284        knows more about this stuff than I do.)
1285    
1286    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1287        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1288        match everything, including newlines. This is not POSIX-compatible, but
1289        somebody wanted the feature. From pcretest it can be activated by using
1290        both the P and the s flags.
1291    
1292    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1293    
1294    19. libpcre.pc was being incorrectly installed as executable.
1295    
1296    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1297        it now also looks for '\r' so that it will work unmodified on Windows.
1298    
1299    21. Added Google's contributed C++ wrapper to the distribution.
1300    
1301    22. Added some untidy missing memory free() calls in pcretest, to keep
1302        Electric Fence happy when testing.
1303    
1304    
1305    
1306    Version 5.0 13-Sep-04
1307    ---------------------
1308    
1309     1. Internal change: literal characters are no longer packed up into items
1310        containing multiple characters in a single byte-string. Each character
1311        is now matched using a separate opcode. However, there may be more than one
1312        byte in the character in UTF-8 mode.
1313    
1314     2. The pcre_callout_block structure has two new fields: pattern_position and
1315        next_item_length. These contain the offset in the pattern to the next match
1316        item, and its length, respectively.
1317    
1318     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1319        insertion of callouts before each pattern item. Added the /C option to
1320        pcretest to make use of this.
1321    
1322     4. On the advice of a Windows user, the lines
1323    
1324          #if defined(_WIN32) || defined(WIN32)
1325          _setmode( _fileno( stdout ), 0x8000 );
1326          #endif  /* defined(_WIN32) || defined(WIN32) */
1327    
1328        have been added to the source of pcretest. This apparently does useful
1329        magic in relation to line terminators.
1330    
1331     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1332        for the benefit of those environments where the "b" makes a difference.
1333    
1334     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1335        to know about it. I have put a hack into configure.in that adds in code
1336        to set GCC=yes if CC=icc. This seems to end up at a point in the
1337        generated configure script that is early enough to affect the setting of
1338        compiler options, which is what is needed, but I have no means of testing
1339        whether it really works. (The user who reported this had patched the
1340        generated configure script, which of course I cannot do.)
1341    
1342        LATER: After change 22 below (new libtool files), the configure script
1343        seems to know about icc (and also ecc). Therefore, I have commented out
1344        this hack in configure.in.
1345    
1346     7. Added support for pkg-config (2 patches were sent in).
1347    
1348     8. Negated POSIX character classes that used a combination of internal tables
1349        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1350        [[:^ascii]]. Typically, they would match almost any characters. The other
1351        POSIX classes were not broken in this way.
1352    
1353     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1354        to find the match, as PCRE was deluded into thinking that the match had to
1355        start at the start point or following a newline. The same bug applied to
1356        patterns with negative forward assertions or any backward assertions
1357        preceding ".*" at the start, unless the pattern required a fixed first
1358        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1359    
1360    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1361        starting at the last subject character, bytes beyond the end of the subject
1362        string were read.
1363    
1364    11. Renamed the variable "class" as "classbits" to make life easier for C++
1365        users. (Previously there was a macro definition, but it apparently wasn't
1366        enough.)
1367    
1368    12. Added the new field "tables" to the extra data so that tables can be passed
1369        in at exec time, or the internal tables can be re-selected. This allows
1370        a compiled regex to be saved and re-used at a later time by a different
1371        program that might have everything at different addresses.
1372    
1373    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1374        -R library as well as a -L library.
1375    
1376    14. The debugging options of pcretest (-d on the command line or D on a
1377        pattern) showed incorrect output for anything following an extended class
1378        that contained multibyte characters and which was followed by a quantifier.
1379    
1380    15. Added optional support for general category Unicode character properties
1381        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1382        support. It adds about 90K to the size of the library. The meanings of the
1383        inbuilt class escapes such as \d and \s have NOT been changed.
1384    
1385    16. Updated pcredemo.c to include calls to free() to release the memory for the
1386        compiled pattern.
1387    
1388    17. The generated file chartables.c was being created in the source directory
1389        instead of in the building directory. This caused the build to fail if the
1390        source directory was different from the building directory, and was
1391        read-only.
1392    
1393    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1394        file. No doubt somebody will tell me if they don't make sense... Also added
1395        Dan Mooney's comments about building on OpenVMS.
1396    
1397    19. Added support for partial matching via the PCRE_PARTIAL option for
1398        pcre_exec() and the \P data escape in pcretest.
1399    
1400    20. Extended pcretest with 3 new pattern features:
1401    
1402        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1403              write the compiled pattern to the file whose name is "rest-of-line".
1404              This is a straight binary dump of the data, with the saved pointer to
1405              the character tables forced to be NULL. The study data, if any, is
1406              written too. After writing, pcretest reads a new pattern.
1407    
1408        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1409              compiled pattern from the given file. There must not be any
1410              occurrences of "<" in the file name (pretty unlikely); if there are,
1411              pcretest will instead treat the initial "<" as a pattern delimiter.
1412              After reading in the pattern, pcretest goes on to read data lines as
1413              usual.
1414    
1415        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1416              and 16-bit fields in a compiled pattern, to simulate a pattern that
1417              was compiled on a host of opposite endianness.
1418    
1419    21. The pcre-exec() function can now cope with patterns that were compiled on
1420        hosts of opposite endianness, with this restriction:
1421    
1422          As for any compiled expression that is saved and used later, the tables
1423          pointer field cannot be preserved; the extra_data field in the arguments
1424          to pcre_exec() should be used to pass in a tables address if a value
1425          other than the default internal tables were used at compile time.
1426    
1427    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1428        now diagnosed as an error. Previously, most of the time, a negative number
1429        would have been treated as zero, but if in addition "ovector" was passed as
1430        NULL, a crash could occur.
1431    
1432    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1433        new versions from the libtool 1.5 distribution (the last one is a copy of
1434        a file called libtool.m4). This seems to have fixed the need to patch
1435        "configure" to support Darwin 1.3 (which I used to do). However, I still
1436        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1437        workstation).
1438    
1439    24. Changed the PCRE licence to be the more standard "BSD" licence.
1440    
1441    
1442    Version 4.5 01-Dec-03
1443    ---------------------
1444    
1445     1. There has been some re-arrangement of the code for the match() function so
1446        that it can be compiled in a version that does not call itself recursively.
1447        Instead, it keeps those local variables that need separate instances for
1448        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1449        needs to "recurse". Keeping track of where control must go is done by means
1450        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1451        hide most of the details from the main code, and operates only if
1452        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1453        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1454        operating.
1455    
1456        To make it easier for callers to provide specially tailored get/free
1457        functions for this usage, two new functions, pcre_stack_malloc, and
1458        pcre_stack_free, are used. They are always called in strict stacking order,
1459        and the size of block requested is always the same.
1460    
1461        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1462        PCRE has been compiled to use the stack or the heap for recursion. The
1463        -C option of pcretest uses this to show which version is compiled.
1464    
1465        A new data escape \S, is added to pcretest; it causes the amounts of store
1466        obtained and freed by both kinds of malloc/free at match time to be added
1467        to the output.
1468    
1469     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1470        what's available on my current Linux desktop machine.
1471    
1472     3. When matching a UTF-8 string, the test for a valid string at the start has
1473        been extended. If start_offset is not zero, PCRE now checks that it points
1474        to a byte that is the start of a UTF-8 character. If not, it returns
1475        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1476        this is necessary because there may be backward assertions in the pattern.
1477        When matching the same subject several times, it may save resources to use
1478        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1479    
1480     4. The code for checking the validity of UTF-8 strings has been tightened so
1481        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1482        containing "overlong sequences".
1483    
1484     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1485        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1486        should have been "&", but it just so happened that all the cases this let
1487        through by mistake were picked up later in the function.
1488    
1489     6. I had used a variable called "isblank" - this is a C99 function, causing
1490        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1491    
1492     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1493        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1494        so the version is shown; (c) stop "make test" echoing "./RunTest".
1495    
1496     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1497    
1498     9. The prototype for memmove() for systems that don't have it was using
1499        size_t, but the inclusion of the header that defines size_t was later. I've
1500        moved the #includes for the C headers earlier to avoid this.
1501    
1502    10. Added some adjustments to the code to make it easier to compiler on certain
1503        special systems:
1504    
1505          (a) Some "const" qualifiers were missing.
1506          (b) Added the macro EXPORT before all exported functions; by default this
1507              is defined to be empty.
1508          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1509              that it reads its output file name as an argument instead of writing
1510              to the standard output and assuming this can be redirected.
1511    
1512    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1513        class containing characters with values greater than 255, PCRE compilation
1514        went into a loop.
1515    
1516    12. A recursive reference to a subpattern that was within another subpattern
1517        that had a minimum quantifier of zero caused PCRE to crash. For example,
1518        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1519        recursion. If the recursively-called subpattern itself had a zero repeat,
1520        that was OK.
1521    
1522    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1523        buffer into which it was copied (for escape processing) was still set at
1524        1024, so long lines caused crashes.
1525    
1526    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1527        "internal error: code overflow...". This applied to any character class
1528        that was followed by a possessive quantifier.
1529    
1530    15. Modified the Makefile to add libpcre.la as a prerequisite for
1531        libpcreposix.la because I was told this is needed for a parallel build to
1532        work.
1533    
1534    16. If a pattern that contained .* following optional items at the start was
1535        studied, the wrong optimizing data was generated, leading to matching
1536        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1537        matching string must start with a or b or c. The correct conclusion for
1538        this pattern is that a match can start with any character.
1539    
1540    
1541    Version 4.4 13-Aug-03
1542    ---------------------
1543    
1544     1. In UTF-8 mode, a character class containing characters with values between
1545        127 and 255 was not handled correctly if the compiled pattern was studied.
1546        In fixing this, I have also improved the studying algorithm for such
1547        classes (slightly).
1548    
1549     2. Three internal functions had redundant arguments passed to them. Removal
1550        might give a very teeny performance improvement.
1551    
1552     3. Documentation bug: the value of the capture_top field in a callout is *one
1553        more than* the number of the hightest numbered captured substring.
1554    
1555     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1556        in incorrectly linking with a previously installed version. They now link
1557        explicitly with libpcre.la.
1558    
1559     5. configure.in no longer needs to recognize Cygwin specially.
1560    
1561     6. A problem in pcre.in for Windows platforms is fixed.
1562    
1563     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1564        pcretest, it used to include the size of the study block as part of its
1565        output. Unfortunately, the structure contains a field that has a different
1566        size on different hardware architectures. This meant that the tests that
1567        showed this size failed. As the block is currently always of a fixed size,
1568        this information isn't actually particularly useful in pcretest output, so
1569        I have just removed it.
1570    
1571     8. Three pre-processor statements accidentally did not start in column 1.
1572        Sadly, there are *still* compilers around that complain, even though
1573        standard C has not required this for well over a decade. Sigh.
1574    
1575     9. In pcretest, the code for checking callouts passed small integers in the
1576        callout_data field, which is a void * field. However, some picky compilers
1577        complained about the casts involved for this on 64-bit systems. Now
1578        pcretest passes the address of the small integer instead, which should get
1579        rid of the warnings.
1580    
1581    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1582        both compile and run time, and gives an error if an invalid UTF-8 sequence
1583        is found. There is a option for disabling this check in cases where the
1584        string is known to be correct and/or the maximum performance is wanted.
1585    
1586    11. In response to a bug report, I changed one line in Makefile.in from
1587    
1588            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1589        to
1590            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1591    
1592        to look similar to other lines, but I have no way of telling whether this
1593        is the right thing to do, as I do not use Windows. No doubt I'll get told
1594        if it's wrong...
1595    
1596    
1597    Version 4.3 21-May-03
1598    ---------------------
1599    
1600    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1601       Makefile.
1602    
1603    2. Some refactoring to improve the quality of the code:
1604    
1605       (i)   The utf8_table... variables are now declared "const".
1606    
1607       (ii)  The code for \cx, which used the "case flipping" table to upper case
1608             lower case letters, now just substracts 32. This is ASCII-specific,
1609             but the whole concept of \cx is ASCII-specific, so it seems
1610             reasonable.
1611    
1612       (iii) PCRE was using its character types table to recognize decimal and
1613             hexadecimal digits in the pattern. This is silly, because it handles
1614             only 0-9, a-f, and A-F, but the character types table is locale-
1615             specific, which means strange things might happen. A private
1616             table is now used for this - though it costs 256 bytes, a table is
1617             much faster than multiple explicit tests. Of course, the standard
1618             character types table is still used for matching digits in subject
1619             strings against \d.
1620    
1621       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1622             ending in _t are). So I've renamed it as ESC_tee.
1623    
1624    3. The first argument for regexec() in the POSIX wrapper should have been
1625       defined as "const".
1626    
1627    4. Changed pcretest to use malloc() for its buffers so that they can be
1628       Electric Fenced for debugging.
1629    
1630    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1631       to read one or more bytes before the start of the subject string. Often this
1632       had no effect on PCRE's behaviour, but in some circumstances it could
1633       provoke a segmentation fault.
1634    
1635    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1636       to try to read one or more bytes before the start of the subject string.
1637    
1638    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1639       UTF-8 support could misbehave in various ways if the subject string
1640       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1641       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1642       back over UTF-8 characters.)
1643    
1644    
1645    Version 4.2 14-Apr-03
1646    ---------------------
1647    
1648    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1649    
1650    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1651         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1652         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1653         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1654         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1655           and BUILD_EXEEXT
1656         Note: automatic setting of the BUILD variables is not yet working
1657         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1658           compile-time but not at link-time
1659         [LINK]: use for linking executables only
1660         make different versions for Windows and non-Windows
1661         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1662           libraries
1663         [LINK_FOR_BUILD]: new variable
1664         [OBJEXT]: use throughout
1665         [EXEEXT]: use throughout
1666         <winshared>: new target
1667         <wininstall>: new target
1668         <dftables.o>: use native compiler
1669         <dftables>: use native linker
1670         <install>: handle Windows platform correctly
1671         <clean>: ditto
1672         <check>: ditto
1673         copy DLL to top builddir before testing
1674    
1675       As part of these changes, -no-undefined was removed again. This was reported
1676       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1677       in any case.
1678    
1679    3. Some tidies to get rid of compiler warnings:
1680    
1681       . In the match_data structure, match_limit was an unsigned long int, whereas
1682         match_call_count was an int. I've made them both unsigned long ints.
1683    
1684       . In pcretest the fact that a const uschar * doesn't automatically cast to
1685         a void * provoked a warning.
1686    
1687       . Turning on some more compiler warnings threw up some "shadow" variables
1688         and a few more missing casts.
1689    
1690    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1691       option, a class that contained a single character with a value between 128
1692       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1693    
1694    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1695       option, a class that contained several characters, but with at least one
1696       whose value was between 128 and 255 caused PCRE to crash.
1697    
1698    
1699    Version 4.1 12-Mar-03
1700    ---------------------
1701    
1702    1. Compiling with gcc -pedantic found a couple of places where casts were
1703    needed, and a string in dftables.c that was longer than standard compilers are
1704    required to support.
1705    
1706    2. Compiling with Sun's compiler found a few more places where the code could
1707    be tidied up in order to avoid warnings.
1708    
1709    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1710    first of these names is deprecated in the latest Autoconf in favour of the name
1711    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1712    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1713    analogy I have changed it to CFLAGS_FOR_BUILD.
1714    
1715    4. Added -no-undefined to the linking command in the Makefile, because this is
1716    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1717    linking step for the pcreposix library.
1718    
1719    5. PCRE was failing to diagnose the case of two named groups with the same
1720    name.
1721    
1722    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1723    literal character that is needed in the subject for a match, and scans along to
1724    ensure that it is present before embarking on the full matching process. This
1725    saves time in cases of nested unlimited repeats that are never going to match.
1726    Problem: the scan can take a lot of time if the subject is very long (e.g.
1727    megabytes), thus penalizing straightforward matches. It is now done only if the
1728    amount of subject to be scanned is less than 1000 bytes.
1729    
1730    7. A lesser problem with the same optimization is that it was recording the
1731    first character of an anchored pattern as "needed", thus provoking a search
1732    right along the subject, even when the first match of the pattern was going to
1733    fail. The "needed" character is now not set for anchored patterns, unless it
1734    follows something in the pattern that is of non-fixed length. Thus, it still
1735    fulfils its original purpose of finding quick non-matches in cases of nested
1736    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1737    
1738    
1739    Version 4.0 17-Feb-03
1740    ---------------------
1741    
1742    1. If a comment in an extended regex that started immediately after a meta-item
1743    extended to the end of string, PCRE compiled incorrect data. This could lead to
1744    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1745    
1746    2. Moved to autoconf 2.53 and libtool 1.4.2.
1747    
1748    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1749    the special perltest8 script is no longer needed - all the tests can be run
1750    from a single perltest script.
1751    
1752    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1753    by \s. It has now been removed in PCRE. This means it isn't recognized as
1754    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1755    class [:space:] *does* include VT, thereby creating a mess.
1756    
1757    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1758    space and tab.
1759    
1760    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1761    its new features into the main test script, reducing the number of scripts.
1762    
1763    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1764    were backward compatible, and made the (?i) apply to the whole pattern, as if
1765    /i were given. Now it behaves more logically, and applies the option setting
1766    only to what follows. PCRE has been changed to follow suit. However, if it
1767    finds options settings right at the start of the pattern, it extracts them into
1768    the global options, as before. Thus, they show up in the info data.
1769    
1770    8. Added support for the \Q...\E escape sequence. Characters in between are
1771    treated as literals. This is slightly different from Perl in that $ and @ are
1772    also handled as literals inside the quotes. In Perl, they will cause variable
1773    interpolation. Note the following examples:
1774    
1775        Pattern            PCRE matches      Perl matches
1776    
1777        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1778        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1779        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1780    
1781    For compatibility with Perl, \Q...\E sequences are recognized inside character
1782    classes as well as outside them.
1783    
1784    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1785    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1786    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1787    signed/unsigned warnings.
1788    
1789    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1790    option for pcretest, so I've replaced it by a simple function that does just
1791    that job.
1792    
1793    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1794    "pcregrep -".
1795    
1796    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1797    Java package. This provides some syntactic sugar for simple cases of what my
1798    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1799    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1800    item, you can use this simplified notation. Note that only makes sense with
1801    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1802    greediness, whatever the setting of the PCRE_UNGREEDY option.
1803    
1804    13. A change of greediness default within a pattern was not taking effect at
1805    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1806    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1807    was abstracted outside.
1808    
1809    14. PCRE now supports the \G assertion. It is true when the current matching
1810    position is at the start point of the match. This differs from \A when the
1811    starting offset is non-zero. Used with the /g option of pcretest (or similar
1812    code), it works in the same way as it does for Perl's /g option. If all
1813    alternatives of a regex begin with \G, the expression is anchored to the start
1814    match position, and the "anchored" flag is set in the compiled expression.
1815    
1816    15. Some bugs concerning the handling of certain option changes within patterns
1817    have been fixed. These applied to options other than (?ims). For example,
1818    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1819    been the other way round. Some of this was related to change 7 above.
1820    
1821    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1822    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1823    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1824    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1825    
1826    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1827    mode. Unlike ".", it always matches newline, whatever the setting of
1828    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1829    assertions. Perl allows it, but it doesn't (in general) work because it can't
1830    calculate the length of the lookbehind. At least, that's the case for Perl
1831    5.8.0 - I've been told they are going to document that it doesn't work in
1832    future.
1833    
1834    18. Added an error diagnosis for escapes that PCRE does not support: these are
1835    \L, \l, \N, \P, \p, \U, \u, and \X.
1836    
1837    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1838    reading past the end of the pattern in cases such as /[abcd/.
1839    
1840    20. PCRE was getting more memory than necessary for patterns with classes that
1841    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1842    
1843    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1844    compiling PCRE for use with Virtual Pascal.
1845    
1846    22. Small fix to the Makefile to make it work properly if the build is done
1847    outside the source tree.
1848    
1849    23. Added a new extension: a condition to go with recursion. If a conditional
1850    subpattern starts with (?(R) the "true" branch is used if recursion has
1851    happened, whereas the "false" branch is used only at the top level.
1852    
1853    24. When there was a very long string of literal characters (over 255 bytes
1854    without UTF support, over 250 bytes with UTF support), the computation of how
1855    much memory was required could be incorrect, leading to segfaults or other
1856    strange effects.
1857    
1858    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1859    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1860    there was a subsequent back reference to those brackets. This meant that, for
1861    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1862    possible to check for precisely this case. All we can do is abandon the
1863    optimization if .* occurs inside capturing brackets when there are any back
1864    references whatsoever. (See below for a better fix that came later.)
1865    
1866    26. The handling of the optimization for finding the first character of a
1867    non-anchored pattern, and for finding a character that is required later in the
1868    match were failing in some cases. This didn't break the matching; it just
1869    failed to optimize when it could. The way this is done has been re-implemented.
1870    
1871    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1872    
1873    28. Added a new feature that provides some of the functionality that Perl
1874    provides with (?{...}). The facility is termed a "callout". The way it is done
1875    in PCRE is for the caller to provide an optional function, by setting
1876    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1877    global variable. By default it is unset, which disables all calling out. To get
1878    the function called, the regex must include (?C) at appropriate points. This
1879    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1880    This provides a means of identifying different callout points. When PCRE
1881    reaches such a point in the regex, if pcre_callout has been set, the external
1882    function is called. It is provided with data in a structure called
1883    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1884    matching continues; if it returns a non-zero value, the match at the current
1885    point fails. However, backtracking will occur if possible. [This was changed
1886    later and other features added - see item 49 below.]
1887    
1888    29. pcretest is upgraded to test the callout functionality. It provides a
1889    callout function that displays information. By default, it shows the start of
1890    the match and the current position in the text. There are some new data escapes
1891    to vary what happens:
1892    
1893        \C+         in addition, show current contents of captured substrings
1894        \C-         do not supply a callout function
1895        \C!n        return 1 when callout number n is reached
1896        \C!n!m      return 1 when callout number n is reached for the mth time
1897    
1898    30. If pcregrep was called with the -l option and just a single file name, it
1899    output "<stdin>" if a match was found, instead of the file name.
1900    
1901    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1902    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1903    pcre_exec(). This saves a malloc/free per call. The default value of
1904    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1905    when configuring.
1906    
1907    32. The default maximum size of a compiled pattern is 64K. There have been a
1908    few cases of people hitting this limit. The code now uses macros to handle the
1909    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1910    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1911    configuring. Tests 2 and 5 work only with 2-byte links because they output
1912    debugging information about compiled patterns.
1913    
1914    33. Internal code re-arrangements:
1915    
1916    (a) Moved the debugging function for printing out a compiled regex into
1917        its own source file (printint.c) and used #include to pull it into
1918        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1919        separate copies.
1920    
1921    (b) Defined the list of op-code names for debugging as a macro in
1922        internal.h so that it is next to the definition of the opcodes.
1923    
1924    (c) Defined a table of op-code lengths for simpler skipping along compiled
1925        code. This is again a macro in internal.h so that it is next to the
1926        definition of the opcodes.
1927    
1928    34. Added support for recursive calls to individual subpatterns, along the
1929    lines of Robin Houston's patch (but implemented somewhat differently).
1930    
1931    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1932    allow it to read and process whole directories in Win32. This code was
1933    contributed by Lionel Fourquaux; it has not been tested by me.
1934    
1935    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1936    used to name a group. Names consist of alphanumerics and underscores, and must
1937    be unique. Back references use the syntax (?P=name) and recursive calls use
1938    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1939    numbers. The function pcre_fullinfo() can be used after compilation to extract
1940    a name/number map. There are three relevant calls:
1941    
1942      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1943      PCRE_INFO_NAMECOUNT            yields the number of entries
1944      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1945    
1946    The map is a vector of fixed-size entries. The size of each entry depends on
1947    the length of the longest name used. The first two bytes of each entry are the
1948    group number, most significant byte first. There follows the corresponding
1949    name, zero terminated. The names are in alphabetical order.
1950    
1951    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1952    case instead of 255. Making it the same both with and without UTF-8 support
1953    means that the same test output works with both.
1954    
1955    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1956    calling malloc() with a zero argument.
1957    
1958    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1959    optimization. I've improved things by keeping a bitmap of backreferences with
1960    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1961    fact referenced, the optimization can be applied. It is unlikely that a
1962    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1963    the match to follow \n) will appear inside brackets with a number greater than
1964    31, but if it does, any back reference > 31 suppresses the optimization.
1965    
1966    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1967    of disabling numbered capturing parentheses. Any opening parenthesis that is
1968    not followed by ? behaves as if it were followed by ?: but named parentheses
1969    can still be used for capturing (and they will acquire numbers in the usual
1970    way).
1971    
1972    41. Redesigned the return codes from the match() function into yes/no/error so
1973    that errors can be passed back from deep inside the nested calls. A malloc
1974    failure while inside a recursive subpattern call now causes the
1975    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1976    
1977    42. It is now possible to set a limit on the number of times the match()
1978    function is called in a call to pcre_exec(). This facility makes it possible to
1979    limit the amount of recursion and backtracking, though not in a directly
1980    obvious way, because the match() function is used in a number of different
1981    circumstances. The count starts from zero for each position in the subject
1982    string (for non-anchored patterns). The default limit is, for compatibility, a
1983    large number, namely 10 000 000. You can change this in two ways:
1984    
1985    (a) When configuring PCRE before making, you can use --with-match-limit=n
1986        to set a default value for the compiled library.
1987    
1988    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1989        a different value is set. See 45 below.
1990    
1991    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1992    
1993    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1994    of things that can be changed at compile time. The first argument specifies
1995    what is wanted and the second points to where the information is to be placed.
1996    The current list of available information is:
1997    
1998      PCRE_CONFIG_UTF8
1999    
2000    The output is an integer that is set to one if UTF-8 support is available;
2001    otherwise it is set to zero.
2002    
2003      PCRE_CONFIG_NEWLINE
2004    
2005    The output is an integer that it set to the value of the code that is used for
2006    newline. It is either LF (10) or CR (13).
2007    
2008      PCRE_CONFIG_LINK_SIZE
2009    
2010    The output is an integer that contains the number of bytes used for internal
2011    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2012    
2013      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2014    
2015    The output is an integer that contains the threshold above which the POSIX
2016    interface uses malloc() for output vectors. See item 31 above.
2017    
2018      PCRE_CONFIG_MATCH_LIMIT
2019    
2020    The output is an unsigned integer that contains the default limit of the number
2021    of match() calls in a pcre_exec() execution. See 42 above.
2022    
2023    44. pcretest has been upgraded by the addition of the -C option. This causes it
2024    to extract all the available output from the new pcre_config() function, and to
2025    output it. The program then exits immediately.
2026    
2027    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2028    order to support additional features. One way would have been to define
2029    pcre_exec2() (for example) with extra arguments, but this would not have been
2030    extensible, and would also have required all calls to the original function to
2031    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2032    is used for passing in "extra" data from pcre_study().
2033    
2034    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2035    contains the following fields:
2036    
2037      flags         a bitmap indicating which of the following fields are set
2038      study_data    opaque data from pcre_study()
2039      match_limit   a way of specifying a limit on match() calls for a specific
2040                      call to pcre_exec()
2041      callout_data  data for callouts (see 49 below)
2042    
2043    The flag bits are also defined in pcre.h, and are
2044    
2045      PCRE_EXTRA_STUDY_DATA
2046      PCRE_EXTRA_MATCH_LIMIT
2047      PCRE_EXTRA_CALLOUT_DATA
2048    
2049    The pcre_study() function now returns one of these new pcre_extra blocks, with
2050    the actual study data pointed to by the study_data field, and the
2051    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2052    before. That is, this change is entirely upwards-compatible and requires no
2053    change to existing code.
2054    
2055    If you want to pass in additional data to pcre_exec(), you can either place it
2056    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2057    block.
2058    
2059    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2060    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2061    times with different match limits, until it finds the minimum value needed for
2062    pcre_exec() to complete. The value is then output. This can be instructive; for
2063    most simple matches the number is quite small, but for pathological cases it
2064    gets very large very quickly.
2065    
2066    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2067    returns the size of the data block pointed to by the study_data field in a
2068    pcre_extra block, that is, the value that was passed as the argument to
2069    pcre_malloc() when PCRE was getting memory in which to place the information
2070    created by pcre_study(). The fourth argument should point to a size_t variable.
2071    pcretest has been extended so that this information is shown after a successful
2072    pcre_study() call when information about the compiled regex is being displayed.
2073    
2074    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2075    because what follows is always an absolute path. (Later: it turns out that this
2076    is more than cosmetic for MinGW, because it doesn't like empty path
2077    components.)
2078    
2079    49. Some changes have been made to the callout feature (see 28 above):
2080    
2081    (i)  A callout function now has three choices for what it returns:
2082    
2083           0  =>  success, carry on matching
2084         > 0  =>  failure at this point, but backtrack if possible
2085         < 0  =>  serious error, return this value from pcre_exec()
2086    
2087         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2088         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2089         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2090         use by callout functions. It will never be used by PCRE itself.
2091    
2092    (ii) The pcre_extra structure (see 45 above) has a void * field called
2093         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2094         pcre_callout_block structure has a field of the same name. The contents of
2095         the field passed in the pcre_extra structure are passed to the callout
2096         function in the corresponding field in the callout block. This makes it
2097         easier to use the same callout-containing regex from multiple threads. For
2098         testing, the pcretest program has a new data escape
2099    
2100           \C*n        pass the number n (may be negative) as callout_data
2101    
2102         If the callout function in pcretest receives a non-zero value as
2103         callout_data, it returns that value.
2104    
2105    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2106    there were some redundant $(CFLAGS) in commands that are now specified as
2107    $(LINK), which already includes $(CFLAGS).
2108    
2109    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2110    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2111    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2112    one-byte characters throughout. Note that case-insensitive matching applies
2113    only to characters whose values are less than 256. PCRE doesn't support the
2114    notion of cases for higher-valued characters.
2115    
2116    (i)   A character class whose characters are all within 0-255 is handled as
2117          a bit map, and the map is inverted for negative classes. Previously, a
2118          character > 255 always failed to match such a class; however it should
2119          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2120    
2121    (ii)  A negated character class with a single character < 255 is coded as
2122          "not this character" (OP_NOT). This wasn't working properly when the test
2123          character was multibyte, either singly or repeated.
2124    
2125    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2126          mode, for example: \x{100}{2,3}.
2127    
2128    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2129          singly or repeated) now correctly test multibyte characters. However,
2130          PCRE doesn't recognize any characters with values greater than 255 as
2131          digits, spaces, or word characters. Such characters always match \D, \S,
2132          and \W, and never match \d, \s, or \w.
2133    
2134    (v)   Classes may now contain characters and character ranges with values
2135          greater than 255. For example: [ab\x{100}-\x{400}].
2136    
2137    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2138          PCRE in UTF-8 mode.
2139    
2140    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2141    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2142    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2143    value.)
2144    
2145    53. The single man page has become too large. I have therefore split it up into
2146    a number of separate man pages. These also give rise to individual HTML pages;
2147    these are now put in a separate directory, and there is an index.html page that
2148    lists them all. Some hyperlinking between the pages has been installed.
2149    
2150    54. Added convenience functions for handling named capturing parentheses.
2151    
2152    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2153    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2154    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2155    are faulted.
2156    
2157    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2158    calling configure. These values are used when compiling the dftables.c program
2159    which is run to generate the source of the default character tables. They
2160    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2161    you will need to set these values.
2162    
2163    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2164    
2165    
2166    Version 3.9 02-Jan-02
2167    ---------------------
2168    
2169    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2170    
2171    2. If --disable-static was given, the building process failed when trying to
2172    build pcretest and pcregrep. (For some reason it was using libtool to compile
2173    them, which is not right, as they aren't part of the library.)
2174    
2175    
2176    Version 3.8 18-Dec-01
2177    ---------------------
2178    
2179    1. The experimental UTF-8 code was completely screwed up. It was packing the
2180    bytes in the wrong order. How dumb can you get?
2181    
2182    
2183    Version 3.7 29-Oct-01
2184    ---------------------
2185    
2186    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2187    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2188    this didn't happen under Solaris 8, where I normally test things.
2189    
2190    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2191    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2192    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2193    this fix an hour or so after the initial 3.7 release.)
2194    
2195    
2196    Version 3.6 23-Oct-01
2197    ---------------------
2198    
2199    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2200    offsets passed as NULL with zero offset count.
2201    
2202    2. The config.guess and config.sub files had not been updated when I moved to
2203    the latest autoconf.
2204    
2205    
2206    Version 3.5 15-Aug-01
2207    ---------------------
2208    
2209    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2210    had been forgotten.
2211    
2212    2. By using declared but undefined structures, we can avoid using "void"
2213    definitions in pcre.h while keeping the internal definitions of the structures
2214    private.
2215    
2216    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2217    user point of view, this means that both static and shared libraries are built
2218    by default, but this can be individually controlled. More of the work of
2219    handling this static/shared cases is now inside libtool instead of PCRE's make
2220    file.
2221    
2222    4. The pcretest utility is now installed along with pcregrep because it is
2223    useful for users (to test regexs) and by doing this, it automatically gets
2224    relinked by libtool. The documentation has been turned into a man page, so
2225    there are now .1, .txt, and .html versions in /doc.
2226    
2227    5. Upgrades to pcregrep:
2228       (i)   Added long-form option names like gnu grep.
2229       (ii)  Added --help to list all options with an explanatory phrase.
2230       (iii) Added -r, --recursive to recurse into sub-directories.
2231       (iv)  Added -f, --file to read patterns from a file.
2232    
2233    6. pcre_exec() was referring to its "code" argument before testing that
2234    argument for NULL (and giving an error if it was NULL).
2235    
2236    7. Upgraded Makefile.in to allow for compiling in a different directory from
2237    the source directory.
2238    
2239    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2240    options bits, the pointer it was passed was to an int instead of to an unsigned
2241    long int. This mattered only on 64-bit systems.
2242    
2243    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2244    generated) instead of pcre.in, which it its source. Also made the same change
2245    in several of the .c files.
2246    
2247    10. A new release of gcc defines printf() as a macro, which broke pcretest
2248    because it had an ifdef in the middle of a string argument for printf(). Fixed
2249    by using separate calls to printf().
2250    
2251    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2252    script, to force use of CR or LF instead of \n in the source. On non-Unix
2253    systems, the value can be set in config.h.
2254    
2255    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2256    absolute limit. Changed the text of the error message to make this clear, and
2257    likewise updated the man page.
2258    
2259    13. The limit of 99 on the number of capturing subpatterns has been removed.
2260    The new limit is 65535, which I hope will not be a "real" limit.
2261    
2262    
2263    Version 3.4 22-Aug-00
2264    ---------------------
2265    
2266    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2267    
2268    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2269    
2270    
2271    Version 3.3 01-Aug-00
2272    ---------------------
2273    
2274    1. If an octal character was given, but the value was greater than \377, it
2275    was not getting masked to the least significant bits, as documented. This could
2276    lead to crashes in some systems.
2277    
2278    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2279    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2280    
2281    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2282    These just pass their arguments on to (pcre_free)(), but they are provided
2283    because some uses of PCRE bind it to non-C systems that can call its functions,
2284    but cannot call free() or pcre_free() directly.
2285    
2286    4. Add "make test" as a synonym for "make check". Corrected some comments in
2287    the Makefile.
2288    
2289    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2290    Makefile.
2291    
2292    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2293    command called pgrep for grepping around the active processes.
2294    
2295    7. Added the beginnings of support for UTF-8 character strings.
2296    
2297    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2298    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2299    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2300    out for the ar command.)
2301    
2302    
2303    Version 3.2 12-May-00
2304    ---------------------
2305    
2306    This is purely a bug fixing release.
2307    
2308    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2309    of ZA. This was just one example of several cases that could provoke this bug,
2310    which was introduced by change 9 of version 2.00. The code for breaking
2311    infinite loops after an iteration that matches an empty string was't working
2312    correctly.
2313    
2314    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2315    when matched against abbab (for example). After matching an empty string, it
2316    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2317    caused it to match further down the string than it should.
2318    
2319    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2320    was there because it doesn't seem to be needed, and it causes trouble on some
2321    systems, as it is not a Standard C header. It has been removed.
2322    
2323    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2324    were reported on the Macintosh. The changes were from
2325    
2326      while ((c = *(++ptr)) != 0 && c != '\n');
2327    to
2328      while ((c = *(++ptr)) != 0 && c != '\n') ;
2329    
2330    Totally extraordinary, but if that's what it takes...
2331    
2332    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2333    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2334    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2335    assumes the way PCRE uses memmove() (always moving upwards).
2336    
2337    6. PCRE is being used in one environment where strchr() is not available. There
2338    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2339    faster code anyway.
2340    
2341    
2342    Version 3.1 09-Feb-00
2343    ---------------------
2344    
2345    The only change in this release is the fixing of some bugs in Makefile.in for
2346    the "install" target:
2347    
2348    (1) It was failing to install pcreposix.h.
2349    
2350    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2351    
2352    
2353  Version 3.0 01-Feb-00  Version 3.0 01-Feb-00
2354  ---------------------  ---------------------

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