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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.3 05-Jul-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    
69    Version 7.2 19-Jun-07
70    ---------------------
71    
72     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
73        which is apparently normally available under Windows.
74    
75     2. Re-jig the pcregrep tests with different newline settings in an attempt
76        to make them independent of the local environment's newline setting.
77    
78     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
79    
80     4. Some of the "internals" tests were previously cut out when the link size
81        was not 2, because the output contained actual offsets. The recent new
82        "Z" feature of pcretest means that these can be cut out, making the tests
83        usable with all link sizes.
84    
85     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
86        stack recursion. This gives a massive performance boost under BSD, but just
87        a small improvement under Linux. However, it saves one field in the frame
88        in all cases.
89    
90     6. Added more features from the forthcoming Perl 5.10:
91    
92        (a) (?-n) (where n is a string of digits) is a relative subroutine or
93            recursion call. It refers to the nth most recently opened parentheses.
94    
95        (b) (?+n) is also a relative subroutine call; it refers to the nth next
96            to be opened parentheses.
97    
98        (c) Conditions that refer to capturing parentheses can be specified
99            relatively, for example, (?(-2)... or (?(+3)...
100    
101        (d) \K resets the start of the current match so that everything before
102            is not part of it.
103    
104        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
105    
106        (f) \g{name} is another synonym - part of Perl 5.10's unification of
107            reference syntax.
108    
109        (g) (?| introduces a group in which the numbering of parentheses in each
110            alternative starts with the same number.
111    
112        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
113    
114     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
115        PCRE_INFO_JCHANGED.
116    
117     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
118        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
119        for detecting groups that can match an empty string.
120    
121     9. A pattern with a very large number of alternatives (more than several
122        hundred) was running out of internal workspace during the pre-compile
123        phase, where pcre_compile() figures out how much memory will be needed. A
124        bit of new cunning has reduced the workspace needed for groups with
125        alternatives. The 1000-alternative test pattern now uses 12 bytes of
126        workspace instead of running out of the 4096 that are available.
127    
128    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
129    
130    11. Applied patch from Google to remove an optimization that didn't quite work.
131        The report of the bug said:
132    
133          pcrecpp::RE("a*").FullMatch("aaa") matches, while
134          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
135          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
136    
137    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
138        it matched the wrong number of bytes.
139    
140    
141    Version 7.1 24-Apr-07
142    ---------------------
143    
144     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
145        that is more "standard", making use of automake and other Autotools. There
146        is some re-arrangement of the files and adjustment of comments consequent
147        on this.
148    
149     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
150        for recursive directory scanning broke on some systems because the files
151        are not scanned in any specific order and on different systems the order
152        was different. A call to "sort" has been inserted into RunGrepTest for the
153        approprate test as a short-term fix. In the longer term there may be an
154        alternative.
155    
156     3. I had an email from Eric Raymond about problems translating some of PCRE's
157        man pages to HTML (despite the fact that I distribute HTML pages, some
158        people do their own conversions for various reasons). The problems
159        concerned the use of low-level troff macros .br and .in. I have therefore
160        removed all such uses from the man pages (some were redundant, some could
161        be replaced by .nf/.fi pairs). The 132html script that I use to generate
162        HTML has been updated to handle .nf/.fi and to complain if it encounters
163        .br or .in.
164    
165     4. Updated comments in configure.ac that get placed in config.h.in and also
166        arranged for config.h to be included in the distribution, with the name
167        config.h.generic, for the benefit of those who have to compile without
168        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
169    
170     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
171        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
172        makevp.bat for the current PCRE, using the additional files
173        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
174    
175     6. A Windows user reported a minor discrepancy with test 2, which turned out
176        to be caused by a trailing space on an input line that had got lost in his
177        copy. The trailing space was an accident, so I've just removed it.
178    
179     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
180        that is needed.
181    
182     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
183        as "const" (a) because they are and (b) because it helps the PHP
184        maintainers who have recently made a script to detect big data structures
185        in the php code that should be moved to the .rodata section. I remembered
186        to update Builducptable as well, so it won't revert if ucptable.h is ever
187        re-created.
188    
189     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
190        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
191        order to be able to cut out the UTF-8 tables in the latter when UTF-8
192        support is not required. This saves 1.5-2K of code, which is important in
193        some applications.
194    
195        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
196        so as not to refer to the tables, even though these functions will never be
197        called when UTF-8 support is disabled. Otherwise there are problems with a
198        shared library.
199    
200    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
201    
202        (a) It was defining its arguments as char * instead of void *.
203    
204        (b) It was assuming that all moves were upwards in memory; this was true
205            a long time ago when I wrote it, but is no longer the case.
206    
207        The emulated memove() is provided for those environments that have neither
208        memmove() nor bcopy(). I didn't think anyone used it these days, but that
209        is clearly not the case, as these two bugs were recently reported.
210    
211    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
212        and Detrail to create the HTML documentation, the .txt form of the man
213        pages, and it removes trailing spaces from listed files. It also creates
214        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
215        case, it wraps all the #defines with #ifndefs. This script should be run
216        before "make dist".
217    
218    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
219        with Unicode property support.
220    
221        (a) For a maximizing quantifier, if the two different cases of the
222            character were of different lengths in their UTF-8 codings (there are
223            some cases like this - I found 11), and the matching function had to
224            back up over a mixture of the two cases, it incorrectly assumed they
225            were both the same length.
226    
227        (b) When PCRE was configured to use the heap rather than the stack for
228            recursion during matching, it was not correctly preserving the data for
229            the other case of a UTF-8 character when checking ahead for a match
230            while processing a minimizing repeat. If the check also involved
231            matching a wide character, but failed, corruption could cause an
232            erroneous result when trying to check for a repeat of the original
233            character.
234    
235    13. Some tidying changes to the testing mechanism:
236    
237        (a) The RunTest script now detects the internal link size and whether there
238            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
239            values substituted by "configure". (The RunGrepTest script already did
240            this for UTF-8.) The configure.ac script no longer substitutes the
241            relevant variables.
242    
243        (b) The debugging options /B and /D in pcretest show the compiled bytecode
244            with length and offset values. This means that the output is different
245            for different internal link sizes. Test 2 is skipped for link sizes
246            other than 2 because of this, bypassing the problem. Unfortunately,
247            there was also a test in test 3 (the locale tests) that used /B and
248            failed for link sizes other than 2. Rather than cut the whole test out,
249            I have added a new /Z option to pcretest that replaces the length and
250            offset values with spaces. This is now used to make test 3 independent
251            of link size. (Test 2 will be tidied up later.)
252    
253    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
254        segmentation fault instead of returning the appropriate error message.
255    
256    15. In multiline mode when the newline sequence was set to "any", the pattern
257        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
258        This doesn't seem right; it now treats the CRLF combination as the line
259        ending, and so does not match in that case. It's only a pattern such as ^$
260        that would hit this one: something like ^ABC$ would have failed after \r
261        and then tried again after \r\n.
262    
263    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
264        in an attempt to make files that differ only in their line terminators
265        compare equal. This works on Linux.
266    
267    17. Under certain error circumstances pcregrep might try to free random memory
268        as it exited. This is now fixed, thanks to valgrind.
269    
270    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
271        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
272        was because its rules for how to advance for /g after matching an empty
273        string at the end of a line did not allow for this case. They now check for
274        it specially.
275    
276    20. pcretest is supposed to handle patterns and data of any length, by
277        extending its buffers when necessary. It was getting this wrong when the
278        buffer for a data line had to be extended.
279    
280    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
281        CRLF as a newline sequence.
282    
283    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
284        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
285        I have nevertheless tidied it up.
286    
287    23. Added some casts to kill warnings from HP-UX ia64 compiler.
288    
289    24. Added a man page for pcre-config.
290    
291    
292    Version 7.0 19-Dec-06
293    ---------------------
294    
295     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
296        moving to gcc 4.1.1.
297    
298     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
299        sys/time.h, which is documented as needed for this function. It doesn't
300        seem to matter on Linux, but it showed up on some releases of OS X.
301    
302     3. It seems that there are systems where bytes whose values are greater than
303        127 match isprint() in the "C" locale. The "C" locale should be the
304        default when a C program starts up. In most systems, only ASCII printing
305        characters match isprint(). This difference caused the output from pcretest
306        to vary, making some of the tests fail. I have changed pcretest so that:
307    
308        (a) When it is outputting text in the compiled version of a pattern, bytes
309            other than 32-126 are always shown as hex escapes.
310    
311        (b) When it is outputting text that is a matched part of a subject string,
312            it does the same, unless a different locale has been set for the match
313            (using the /L modifier). In this case, it uses isprint() to decide.
314    
315     4. Fixed a major bug that caused incorrect computation of the amount of memory
316        required for a compiled pattern when options that changed within the
317        pattern affected the logic of the preliminary scan that determines the
318        length. The relevant options are -x, and -i in UTF-8 mode. The result was
319        that the computed length was too small. The symptoms of this bug were
320        either the PCRE error "internal error: code overflow" from pcre_compile(),
321        or a glibc crash with a message such as "pcretest: free(): invalid next
322        size (fast)". Examples of patterns that provoked this bug (shown in
323        pcretest format) are:
324    
325          /(?-x: )/x
326          /(?x)(?-x: \s*#\s*)/
327          /((?i)[\x{c0}])/8
328          /(?i:[\x{c0}])/8
329    
330        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
331        is now done differently.
332    
333     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
334        wrapper classes; (b) implement a new function in the C++ scanner that is
335        more efficient than the old way of doing things because it avoids levels of
336        recursion in the regex matching; (c) add a paragraph to the documentation
337        for the FullMatch() function.
338    
339     6. The escape sequence \n was being treated as whatever was defined as
340        "newline". Not only was this contrary to the documentation, which states
341        that \n is character 10 (hex 0A), but it also went horribly wrong when
342        "newline" was defined as CRLF. This has been fixed.
343    
344     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
345        was being set to -1 for the "end of line" case (supposedly a value that no
346        character can have). Though this value is never used (the check for end of
347        line is "zero bytes in current character"), it caused compiler complaints.
348        I've changed it to 0xffffffff.
349    
350     8. In pcre_version.c, the version string was being built by a sequence of
351        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
352        string (as it is for production releases) called a macro with an empty
353        argument. The C standard says the result of this is undefined. The gcc
354        compiler treats it as an empty string (which was what was wanted) but it is
355        reported that Visual C gives an error. The source has been hacked around to
356        avoid this problem.
357    
358     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
359        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
360        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
361        of them did).
362    
363    10. Originally, pcretest opened its input and output without "b"; then I was
364        told that "b" was needed in some environments, so it was added for release
365        5.0 to both the input and output. (It makes no difference on Unix-like
366        systems.) Later I was told that it is wrong for the input on Windows. I've
367        now abstracted the modes into two macros, to make it easier to fiddle with
368        them, and removed "b" from the input mode under Windows.
369    
370    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
371    
372    12. Added -help and --help to pcretest as an official way of being reminded
373        of the options.
374    
375    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
376        and pcrecpp.cc because they annoy compilers at high warning levels.
377    
378    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
379    
380    15. Fixed an occurrence of == in configure.ac that should have been = (shell
381        scripts are not C programs :-) and which was not noticed because it works
382        on Linux.
383    
384    16. pcretest is supposed to handle any length of pattern and data line (as one
385        line or as a continued sequence of lines) by extending its input buffer if
386        necessary. This feature was broken for very long pattern lines, leading to
387        a string of junk being passed to pcre_compile() if the pattern was longer
388        than about 50K.
389    
390    17. I have done a major re-factoring of the way pcre_compile() computes the
391        amount of memory needed for a compiled pattern. Previously, there was code
392        that made a preliminary scan of the pattern in order to do this. That was
393        OK when PCRE was new, but as the facilities have expanded, it has become
394        harder and harder to keep it in step with the real compile phase, and there
395        have been a number of bugs (see for example, 4 above). I have now found a
396        cunning way of running the real compile function in a "fake" mode that
397        enables it to compute how much memory it would need, while actually only
398        ever using a few hundred bytes of working memory and without too many
399        tests of the mode. This should make future maintenance and development
400        easier. A side effect of this work is that the limit of 200 on the nesting
401        depth of parentheses has been removed (though this was never a serious
402        limitation, I suspect). However, there is a downside: pcre_compile() now
403        runs more slowly than before (30% or more, depending on the pattern). I
404        hope this isn't a big issue. There is no effect on runtime performance.
405    
406    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
407        newline (only possible for the last line of a file) and it was a
408        pattern that set a locale (followed by /Lsomething), pcretest crashed.
409    
410    19. Added additional timing features to pcretest. (1) The -tm option now times
411        matching only, not compiling. (2) Both -t and -tm can be followed, as a
412        separate command line item, by a number that specifies the number of
413        repeats to use when timing. The default is 50000; this gives better
414        precision, but takes uncomfortably long for very large patterns.
415    
416    20. Extended pcre_study() to be more clever in cases where a branch of a
417        subpattern has no definite first character. For example, (a*|b*)[cd] would
418        previously give no result from pcre_study(). Now it recognizes that the
419        first character must be a, b, c, or d.
420    
421    21. There was an incorrect error "recursive call could loop indefinitely" if
422        a subpattern (or the entire pattern) that was being tested for matching an
423        empty string contained only one non-empty item after a nested subpattern.
424        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
425        incorrectly, because the \d was being skipped in the check.
426    
427    22. The pcretest program now has a new pattern option /B and a command line
428        option -b, which is equivalent to adding /B to every pattern. This causes
429        it to show the compiled bytecode, without the additional information that
430        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
431        is the same as /B/I).
432    
433    23. A new optimization is now able automatically to treat some sequences such
434        as a*b as a*+b. More specifically, if something simple (such as a character
435        or a simple class like \d) has an unlimited quantifier, and is followed by
436        something that cannot possibly match the quantified thing, the quantifier
437        is automatically "possessified".
438    
439    24. A recursive reference to a subpattern whose number was greater than 39
440        went wrong under certain circumstances in UTF-8 mode. This bug could also
441        have affected the operation of pcre_study().
442    
443    25. Realized that a little bit of performance could be had by replacing
444        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
445    
446    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
447    
448    27. Possessive quantifiers such as a++ were previously implemented by turning
449        them into atomic groups such as ($>a+). Now they have their own opcodes,
450        which improves performance. This includes the automatically created ones
451        from 23 above.
452    
453    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
454        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
455        the first matched character to be a colon. This applied both to named and
456        numbered groups.
457    
458    29. The ucpinternal.h header file was missing its idempotency #ifdef.
459    
460    30. I was sent a "project" file called libpcre.a.dev which I understand makes
461        building PCRE on Windows easier, so I have included it in the distribution.
462    
463    31. There is now a check in pcretest against a ridiculously large number being
464        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
465        loop, the loop is abandoned.
466    
467    32. Forward references to subpatterns in conditions such as (?(2)...) where
468        subpattern 2 is defined later cause pcre_compile() to search forwards in
469        the pattern for the relevant set of parentheses. This search went wrong
470        when there were unescaped parentheses in a character class, parentheses
471        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
472    
473    33. "Subroutine" calls and backreferences were previously restricted to
474        referencing subpatterns earlier in the regex. This restriction has now
475        been removed.
476    
477    34. Added a number of extra features that are going to be in Perl 5.10. On the
478        whole, these are just syntactic alternatives for features that PCRE had
479        previously implemented using the Python syntax or my own invention. The
480        other formats are all retained for compatibility.
481    
482        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
483            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
484            also .NET compatible.
485    
486        (b) A recursion or subroutine call to a named group can now be defined as
487            (?&name) as well as (?P>name).
488    
489        (c) A backreference to a named group can now be defined as \k<name> or
490            \k'name' as well as (?P=name). The new forms, as well as being in Perl
491            5.10, are also .NET compatible.
492    
493        (d) A conditional reference to a named group can now use the syntax
494            (?(<name>) or (?('name') as well as (?(name).
495    
496        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
497            groups (named and numbered) that are never evaluated inline, but can be
498            called as "subroutines" from elsewhere. In effect, the DEFINE condition
499            is always false. There may be only one alternative in such a group.
500    
501        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
502            as the simple (?(R). The condition is true only if the most recent
503            recursion is that of the given number or name. It does not search out
504            through the entire recursion stack.
505    
506        (g) The escape \gN or \g{N} has been added, where N is a positive or
507            negative number, specifying an absolute or relative reference.
508    
509    35. Tidied to get rid of some further signed/unsigned compiler warnings and
510        some "unreachable code" warnings.
511    
512    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
513        things, this adds five new scripts.
514    
515    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
516        There were also incompatibilities regarding the handling of \Q..\E inside
517        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
518        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
519    
520    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
521        matches an empty string, and forcibly breaks the loop. There were bugs in
522        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
523        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
524        separate and independent bugs (that affected different cases) have been
525        fixed.
526    
527    39. Refactored the code to abolish the use of different opcodes for small
528        capturing bracket numbers. This is a tidy that I avoided doing when I
529        removed the limit on the number of capturing brackets for 3.5 back in 2001.
530        The new approach is not only tidier, it makes it possible to reduce the
531        memory needed to fix the previous bug (38).
532    
533    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
534        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
535        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
536        mode.
537    
538    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
539        report.
540    
541    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
542        copy construction and assignment in the C++ wrapper.
543    
544    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
545        couple of bugs that could have given wrong results in the "--newline=crlf"
546        case.
547    
548    44. Added a number of casts and did some reorganization of signed/unsigned int
549        variables following suggestions from Dair Grant. Also renamed the variable
550        "this" as "item" because it is a C++ keyword.
551    
552    45. Arranged for dftables to add
553    
554          #include "pcre_internal.h"
555    
556        to pcre_chartables.c because without it, gcc 4.x may remove the array
557        definition from the final binary if PCRE is built into a static library and
558        dead code stripping is activated.
559    
560    46. For an unanchored pattern, if a match attempt fails at the start of a
561        newline sequence, and the newline setting is CRLF or ANY, and the next two
562        characters are CRLF, advance by two characters instead of one.
563    
564    
565    Version 6.7 04-Jul-06
566    ---------------------
567    
568     1. In order to handle tests when input lines are enormously long, pcretest has
569        been re-factored so that it automatically extends its buffers when
570        necessary. The code is crude, but this _is_ just a test program. The
571        default size has been increased from 32K to 50K.
572    
573     2. The code in pcre_study() was using the value of the re argument before
574        testing it for NULL. (Of course, in any sensible call of the function, it
575        won't be NULL.)
576    
577     3. The memmove() emulation function in pcre_internal.h, which is used on
578        systems that lack both memmove() and bcopy() - that is, hardly ever -
579        was missing a "static" storage class specifier.
580    
581     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
582        containing an extended class (one that cannot be represented by a bitmap
583        because it contains high-valued characters or Unicode property items, e.g.
584        [\pZ]). Almost always one would set UTF-8 mode when processing such a
585        pattern, but PCRE should not loop if you do not (it no longer does).
586        [Detail: two cases were found: (a) a repeated subpattern containing an
587        extended class; (b) a recursive reference to a subpattern that followed a
588        previous extended class. It wasn't skipping over the extended class
589        correctly when UTF-8 mode was not set.]
590    
591     5. A negated single-character class was not being recognized as fixed-length
592        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
593        compile error "lookbehind assertion is not fixed length".
594    
595     6. The RunPerlTest auxiliary script was showing an unexpected difference
596        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
597        write a Perl script that can interpret lines of an input file either as
598        byte characters or as UTF-8, which is what "perltest" was being required to
599        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
600        can't do is switch easily at run time between having the "use utf8;" pragma
601        or not. In the end, I fudged it by using the RunPerlTest script to insert
602        "use utf8;" explicitly for the UTF-8 tests.
603    
604     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
605        the end of the subject string, contrary to the documentation and to what
606        Perl does. This was true of both matching functions. Now it matches only at
607        the start of the subject and immediately after *internal* newlines.
608    
609     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
610        a pointer to an int instead of a pointer to an unsigned long int. This
611        caused problems on 64-bit systems.
612    
613     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
614        instance of the 'standard' template library not being so standard".
615    
616    10. There was no check on the number of named subpatterns nor the maximum
617        length of a subpattern name. The product of these values is used to compute
618        the size of the memory block for a compiled pattern. By supplying a very
619        long subpattern name and a large number of named subpatterns, the size
620        computation could be caused to overflow. This is now prevented by limiting
621        the length of names to 32 characters, and the number of named subpatterns
622        to 10,000.
623    
624    11. Subpatterns that are repeated with specific counts have to be replicated in
625        the compiled pattern. The size of memory for this was computed from the
626        length of the subpattern and the repeat count. The latter is limited to
627        65535, but there was no limit on the former, meaning that integer overflow
628        could in principle occur. The compiled length of a repeated subpattern is
629        now limited to 30,000 bytes in order to prevent this.
630    
631    12. Added the optional facility to have named substrings with the same name.
632    
633    13. Added the ability to use a named substring as a condition, using the
634        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
635        are numbers (not recommended). Forward references are permitted.
636    
637    14. Added forward references in named backreferences (if you see what I mean).
638    
639    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
640        pattern could run off the end of the subject. For example, the pattern
641        "(?s)(.{1,5})"8 did this with the subject "ab".
642    
643    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
644        PCRE_CASELESS was set when matching characters that were quantified with ?
645        or *.
646    
647    17. A character class other than a single negated character that had a minimum
648        but no maximum quantifier - for example [ab]{6,} - was not handled
649        correctly by pce_dfa_exec(). It would match only one character.
650    
651    18. A valid (though odd) pattern that looked like a POSIX character
652        class but used an invalid character after [ (for example [[,abc,]]) caused
653        pcre_compile() to give the error "Failed: internal error: code overflow" or
654        in some cases to crash with a glibc free() error. This could even happen if
655        the pattern terminated after [[ but there just happened to be a sequence of
656        letters, a binary zero, and a closing ] in the memory that followed.
657    
658    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
659        over the years. Originally (before any Unicode support), just the bottom 8
660        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
661        output from "man perlunicode" includes this:
662    
663          The regular expression compiler produces polymorphic opcodes.  That
664          is, the pattern adapts to the data and automatically switches to
665          the Unicode character scheme when presented with Unicode data--or
666          instead uses a traditional byte scheme when presented with byte
667          data.
668    
669        Sadly, a wide octal escape does not cause a switch, and in a string with
670        no other multibyte characters, these octal escapes are treated as before.
671        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
672        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
673        Unicode string.
674    
675        I have not perpetrated such confusion in PCRE. Up till now, it took just
676        the bottom 8 bits, as in old Perl. I have now made octal escapes with
677        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
678        translate to the appropriate multibyte character.
679    
680    29. Applied some refactoring to reduce the number of warnings from Microsoft
681        and Borland compilers. This has included removing the fudge introduced
682        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
683        a warning about an unused variable.
684    
685    21. PCRE has not included VT (character 0x0b) in the set of whitespace
686        characters since release 4.0, because Perl (from release 5.004) does not.
687        [Or at least, is documented not to: some releases seem to be in conflict
688        with the documentation.] However, when a pattern was studied with
689        pcre_study() and all its branches started with \s, PCRE still included VT
690        as a possible starting character. Of course, this did no harm; it just
691        caused an unnecessary match attempt.
692    
693    22. Removed a now-redundant internal flag bit that recorded the fact that case
694        dependency changed within the pattern. This was once needed for "required
695        byte" processing, but is no longer used. This recovers a now-scarce options
696        bit. Also moved the least significant internal flag bit to the most-
697        significant bit of the word, which was not previously used (hangover from
698        the days when it was an int rather than a uint) to free up another bit for
699        the future.
700    
701    23. Added support for CRLF line endings as well as CR and LF. As well as the
702        default being selectable at build time, it can now be changed at runtime
703        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
704        specify that it is scanning data with non-default line endings.
705    
706    24. Changed the definition of CXXLINK to make it agree with the definition of
707        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
708    
709    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
710        recursions. This makes a big different to stack usage for some patterns.
711    
712    26. If a subpattern containing a named recursion or subroutine reference such
713        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
714        the space required for the compiled pattern went wrong and gave too small a
715        value. Depending on the environment, this could lead to "Failed: internal
716        error: code overflow at offset 49" or "glibc detected double free or
717        corruption" errors.
718    
719    27. Applied patches from Google (a) to support the new newline modes and (b) to
720        advance over multibyte UTF-8 characters in GlobalReplace.
721    
722    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
723        difference for some implementation of PCRE in some Windows version.
724    
725    29. Added some extra testing facilities to pcretest:
726    
727        \q<number>   in a data line sets the "match limit" value
728        \Q<number>   in a data line sets the "match recursion limt" value
729        -S <number>  sets the stack size, where <number> is in megabytes
730    
731        The -S option isn't available for Windows.
732    
733    
734    Version 6.6 06-Feb-06
735    ---------------------
736    
737     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
738        in pcreposix.h. I have copied the definition from pcre.h.
739    
740     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
741        because pcre.h is no longer a built file.
742    
743     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
744        not normally included in the compiled code.
745    
746    
747    Version 6.5 01-Feb-06
748    ---------------------
749    
750     1. When using the partial match feature with pcre_dfa_exec(), it was not
751        anchoring the second and subsequent partial matches at the new starting
752        point. This could lead to incorrect results. For example, with the pattern
753        /1234/, partially matching against "123" and then "a4" gave a match.
754    
755     2. Changes to pcregrep:
756    
757        (a) All non-match returns from pcre_exec() were being treated as failures
758            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
759            error message is output. Some extra information is given for the
760            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
761            probably the only errors that are likely to be caused by users (by
762            specifying a regex that has nested indefinite repeats, for instance).
763            If there are more than 20 of these errors, pcregrep is abandoned.
764    
765        (b) A binary zero was treated as data while matching, but terminated the
766            output line if it was written out. This has been fixed: binary zeroes
767            are now no different to any other data bytes.
768    
769        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
770            used to set a locale for matching. The --locale=xxxx long option has
771            been added (no short equivalent) to specify a locale explicitly on the
772            pcregrep command, overriding the environment variables.
773    
774        (d) When -B was used with -n, some line numbers in the output were one less
775            than they should have been.
776    
777        (e) Added the -o (--only-matching) option.
778    
779        (f) If -A or -C was used with -c (count only), some lines of context were
780            accidentally printed for the final match.
781    
782        (g) Added the -H (--with-filename) option.
783    
784        (h) The combination of options -rh failed to suppress file names for files
785            that were found from directory arguments.
786    
787        (i) Added the -D (--devices) and -d (--directories) options.
788    
789        (j) Added the -F (--fixed-strings) option.
790    
791        (k) Allow "-" to be used as a file name for -f as well as for a data file.
792    
793        (l) Added the --colo(u)r option.
794    
795        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
796            is not present by default.
797    
798     3. A nasty bug was discovered in the handling of recursive patterns, that is,
799        items such as (?R) or (?1), when the recursion could match a number of
800        alternatives. If it matched one of the alternatives, but subsequently,
801        outside the recursion, there was a failure, the code tried to back up into
802        the recursion. However, because of the way PCRE is implemented, this is not
803        possible, and the result was an incorrect result from the match.
804    
805        In order to prevent this happening, the specification of recursion has
806        been changed so that all such subpatterns are automatically treated as
807        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
808    
809     4. I had overlooked the fact that, in some locales, there are characters for
810        which isalpha() is true but neither isupper() nor islower() are true. In
811        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
812        and ordfeminine) are like this. This affected the treatment of \w and \W
813        when they appeared in character classes, but not when they appeared outside
814        a character class. The bit map for "word" characters is now created
815        separately from the results of isalnum() instead of just taking it from the
816        upper, lower, and digit maps. (Plus the underscore character, of course.)
817    
818     5. The above bug also affected the handling of POSIX character classes such as
819        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
820        permanent tables. Instead, the bit maps for such a class were previously
821        created as the appropriate unions of the upper, lower, and digit bitmaps.
822        Now they are created by subtraction from the [[:word:]] class, which has
823        its own bitmap.
824    
825     6. The [[:blank:]] character class matches horizontal, but not vertical space.
826        It is created by subtracting the vertical space characters (\x09, \x0a,
827        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
828        subtraction was done in the overall bitmap for a character class, meaning
829        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
830        be recognized. This bug has been fixed.
831    
832     7. Patches from the folks at Google:
833    
834          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
835          real life, but is still worth protecting against".
836    
837          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
838          regular expressions".
839    
840          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
841          have it.
842    
843          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
844          "configure" and the latter not, in order to fix a problem somebody had
845          with compiling the Arg class on HP-UX.
846    
847          (e) Improve the error-handling of the C++ wrapper a little bit.
848    
849          (f) New tests for checking recursion limiting.
850    
851     8. The pcre_memmove() function, which is used only if the environment does not
852        have a standard memmove() function (and is therefore rarely compiled),
853        contained two bugs: (a) use of int instead of size_t, and (b) it was not
854        returning a result (though PCRE never actually uses the result).
855    
856     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
857        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
858        returned instead of calling malloc() with an overflowing number that would
859        most likely cause subsequent chaos.
860    
861    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
862    
863    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
864        with this option is matched, the nmatch and pmatch options of regexec() are
865        ignored.
866    
867    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
868        provided in case anyone wants to the the POSIX interface with UTF-8
869        strings.
870    
871    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
872        C++ linking (needed for some HP-UX environments).
873    
874    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
875        (unused parameter) and in the pcre_printint() function (omitted "default"
876        switch label when the default is to do nothing).
877    
878    15. Added some code to make it possible, when PCRE is compiled as a C++
879        library, to replace subject pointers for pcre_exec() with a smart pointer
880        class, thus making it possible to process discontinuous strings.
881    
882    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
883        much the same function. They were added by different people who were trying
884        to make PCRE easy to compile on non-Unix systems. It has been suggested
885        that PCRE_EXPORT be abolished now that there is more automatic apparatus
886        for compiling on Windows systems. I have therefore replaced it with
887        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
888        defaults to "extern" for C or "extern C" for C++, which works fine on
889        Unix-like systems. It is now possible to override the value of PCRE_DATA_
890        SCOPE with something explicit in config.h. In addition:
891    
892        (a) pcreposix.h still had just "extern" instead of either of these macros;
893            I have replaced it with PCRE_DATA_SCOPE.
894    
895        (b) Functions such as _pcre_xclass(), which are internal to the library,
896            but external in the C sense, all had PCRE_EXPORT in their definitions.
897            This is apparently wrong for the Windows case, so I have removed it.
898            (It makes no difference on Unix-like systems.)
899    
900    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
901        of recursive calls to match(). This is different to MATCH_LIMIT because
902        that limits the total number of calls to match(), not all of which increase
903        the depth of recursion. Limiting the recursion depth limits the amount of
904        stack (or heap if NO_RECURSE is set) that is used. The default can be set
905        when PCRE is compiled, and changed at run time. A patch from Google adds
906        this functionality to the C++ interface.
907    
908    18. Changes to the handling of Unicode character properties:
909    
910        (a) Updated the table to Unicode 4.1.0.
911    
912        (b) Recognize characters that are not in the table as "Cn" (undefined).
913    
914        (c) I revised the way the table is implemented to a much improved format
915            which includes recognition of ranges. It now supports the ranges that
916            are defined in UnicodeData.txt, and it also amalgamates other
917            characters into ranges. This has reduced the number of entries in the
918            table from around 16,000 to around 3,000, thus reducing its size
919            considerably. I realized I did not need to use a tree structure after
920            all - a binary chop search is just as efficient. Having reduced the
921            number of entries, I extended their size from 6 bytes to 8 bytes to
922            allow for more data.
923    
924        (d) Added support for Unicode script names via properties such as \p{Han}.
925    
926    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
927        matching that character.
928    
929    20. When matching a repeated Unicode property with a minimum greater than zero,
930        (for example \pL{2,}), PCRE could look past the end of the subject if it
931        reached it while seeking the minimum number of characters. This could
932        happen only if some of the characters were more than one byte long, because
933        there is a check for at least the minimum number of bytes.
934    
935    21. Refactored the implementation of \p and \P so as to be more general, to
936        allow for more different types of property in future. This has changed the
937        compiled form incompatibly. Anybody with saved compiled patterns that use
938        \p or \P will have to recompile them.
939    
940    22. Added "Any" and "L&" to the supported property types.
941    
942    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
943        but give a compile time error if the value is greater than 0xff.
944    
945    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
946        accidentally not being installed or uninstalled.
947    
948    25. The pcre.h file was built from pcre.h.in, but the only changes that were
949        made were to insert the current release number. This seemed silly, because
950        it made things harder for people building PCRE on systems that don't run
951        "configure". I have turned pcre.h into a distributed file, no longer built
952        by "configure", with the version identification directly included. There is
953        no longer a pcre.h.in file.
954    
955        However, this change necessitated a change to the pcre-config script as
956        well. It is built from pcre-config.in, and one of the substitutions was the
957        release number. I have updated configure.ac so that ./configure now finds
958        the release number by grepping pcre.h.
959    
960    26. Added the ability to run the tests under valgrind.
961    
962    
963    Version 6.4 05-Sep-05
964    ---------------------
965    
966     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
967        "--" to be printed when multiple files were scanned, even when none of the
968        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
969        consider it to be a bug, and have restored the previous behaviour.
970    
971     2. A couple of code tidies to get rid of compiler warnings.
972    
973     3. The pcretest program used to cheat by referring to symbols in the library
974        whose names begin with _pcre_. These are internal symbols that are not
975        really supposed to be visible externally, and in some environments it is
976        possible to suppress them. The cheating is now confined to including
977        certain files from the library's source, which is a bit cleaner.
978    
979     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
980        file's purpose clearer.
981    
982     5. Reorganized pcre_ucp_findchar().
983    
984    
985    Version 6.3 15-Aug-05
986    ---------------------
987    
988     1. The file libpcre.pc.in did not have general read permission in the tarball.
989    
990     2. There were some problems when building without C++ support:
991    
992        (a) If C++ support was not built, "make install" and "make test" still
993            tried to test it.
994    
995        (b) There were problems when the value of CXX was explicitly set. Some
996            changes have been made to try to fix these, and ...
997    
998        (c) --disable-cpp can now be used to explicitly disable C++ support.
999    
1000        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1001            backslash in a target when C++ was disabled. This confuses some
1002            versions of "make", apparently. Using an intermediate variable solves
1003            this. (Same for CPP_LOBJ.)
1004    
1005     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1006        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1007        necessary on certain architectures.
1008    
1009     4. Added a setting of -export-symbols-regex to the link command to remove
1010        those symbols that are exported in the C sense, but actually are local
1011        within the library, and not documented. Their names all begin with
1012        "_pcre_". This is not a perfect job, because (a) we have to except some
1013        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1014        available (and never for static libraries). I have made a note to try to
1015        find a way round (a) in the future.
1016    
1017    
1018    Version 6.2 01-Aug-05
1019    ---------------------
1020    
1021     1. There was no test for integer overflow of quantifier values. A construction
1022        such as {1111111111111111} would give undefined results. What is worse, if
1023        a minimum quantifier for a parenthesized subpattern overflowed and became
1024        negative, the calculation of the memory size went wrong. This could have
1025        led to memory overwriting.
1026    
1027     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1028    
1029     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1030        operating environments where this matters.
1031    
1032     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1033        PCRE options from within the C++ wrapper.
1034    
1035     5. Named capturing subpatterns were not being correctly counted when a pattern
1036        was compiled. This caused two problems: (a) If there were more than 100
1037        such subpatterns, the calculation of the memory needed for the whole
1038        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1039        back references of the form \12, where the number was greater than 9, were
1040        not recognized as back references, even though there were sufficient
1041        previous subpatterns.
1042    
1043     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1044        versions of gcc, e.g. 2.95.4.
1045    
1046    
1047    Version 6.1 21-Jun-05
1048    ---------------------
1049    
1050     1. There was one reference to the variable "posix" in pcretest.c that was not
1051        surrounded by "#if !defined NOPOSIX".
1052    
1053     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1054        the cross-check on the old pcre_info() function, for the benefit of the
1055        cut-down version of PCRE that is currently imported into Exim.
1056    
1057     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1058        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1059        patterns that start (?i) but I don't think that matters. The use of (?i) is
1060        just an example; this all applies to the other options as well.
1061    
1062     4. Since libtool seems to echo the compile commands it is issuing, the output
1063        from "make" can be reduced a bit by putting "@" in front of each libtool
1064        compile command.
1065    
1066     5. Patch from the folks at Google for configure.in to be a bit more thorough
1067        in checking for a suitable C++ installation before trying to compile the
1068        C++ stuff. This should fix a reported problem when a compiler was present,
1069        but no suitable headers.
1070    
1071     6. The man pages all had just "PCRE" as their title. I have changed them to
1072        be the relevant file name. I have also arranged that these names are
1073        retained in the file doc/pcre.txt, which is a concatenation in text format
1074        of all the man pages except the little individual ones for each function.
1075    
1076     7. The NON-UNIX-USE file had not been updated for the different set of source
1077        files that come with release 6. I also added a few comments about the C++
1078        wrapper.
1079    
1080    
1081    Version 6.0 07-Jun-05
1082    ---------------------
1083    
1084     1. Some minor internal re-organization to help with my DFA experiments.
1085    
1086     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1087        didn't matter for the library itself when fully configured, but did matter
1088        when compiling without UCP support, or within Exim, where the ucp files are
1089        not imported.
1090    
1091     3. Refactoring of the library code to split up the various functions into
1092        different source modules. The addition of the new DFA matching code (see
1093        below) to a single monolithic source would have made it really too
1094        unwieldy, quite apart from causing all the code to be include in a
1095        statically linked application, when only some functions are used. This is
1096        relevant even without the DFA addition now that patterns can be compiled in
1097        one application and matched in another.
1098    
1099        The downside of splitting up is that there have to be some external
1100        functions and data tables that are used internally in different modules of
1101        the library but which are not part of the API. These have all had their
1102        names changed to start with "_pcre_" so that they are unlikely to clash
1103        with other external names.
1104    
1105     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1106        a different (DFA) algorithm. Although it is slower than the original
1107        function, it does have some advantages for certain types of matching
1108        problem.
1109    
1110     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1111        including restarting after a partial match.
1112    
1113     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1114        defined when compiling for Windows was sent to me. I have put it into the
1115        code, though I have no means of testing or verifying it.
1116    
1117     7. Added the pcre_refcount() auxiliary function.
1118    
1119     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1120        match before or at the first newline in the subject string. In pcretest,
1121        the /f option on a pattern can be used to set this.
1122    
1123     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1124        would behave wrongly. This has been present in PCRE since release 4.0.
1125    
1126    10. A number of changes to the pcregrep command:
1127    
1128        (a) Refactored how -x works; insert ^(...)$ instead of setting
1129            PCRE_ANCHORED and checking the length, in preparation for adding
1130            something similar for -w.
1131    
1132        (b) Added the -w (match as a word) option.
1133    
1134        (c) Refactored the way lines are read and buffered so as to have more
1135            than one at a time available.
1136    
1137        (d) Implemented a pcregrep test script.
1138    
1139        (e) Added the -M (multiline match) option. This allows patterns to match
1140            over several lines of the subject. The buffering ensures that at least
1141            8K, or the rest of the document (whichever is the shorter) is available
1142            for matching (and similarly the previous 8K for lookbehind assertions).
1143    
1144        (f) Changed the --help output so that it now says
1145    
1146              -w, --word-regex(p)
1147    
1148            instead of two lines, one with "regex" and the other with "regexp"
1149            because that confused at least one person since the short forms are the
1150            same. (This required a bit of code, as the output is generated
1151            automatically from a table. It wasn't just a text change.)
1152    
1153        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1154            option but starts with a hyphen. Could be a pattern or a path name
1155            starting with a hyphen, for instance.
1156    
1157        (h) "-" can be given as a file name to represent stdin.
1158    
1159        (i) When file names are being printed, "(standard input)" is used for
1160            the standard input, for compatibility with GNU grep. Previously
1161            "<stdin>" was used.
1162    
1163        (j) The option --label=xxx can be used to supply a name to be used for
1164            stdin when file names are being printed. There is no short form.
1165    
1166        (k) Re-factored the options decoding logic because we are going to add
1167            two more options that take data. Such options can now be given in four
1168            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1169    
1170        (l) Added the -A, -B, and -C options for requesting that lines of context
1171            around matches be printed.
1172    
1173        (m) Added the -L option to print the names of files that do not contain
1174            any matching lines, that is, the complement of -l.
1175    
1176        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1177            continue to scan other files.
1178    
1179        (o) The -s option was incorrectly implemented. For compatibility with other
1180            greps, it now suppresses the error message for a non-existent or non-
1181            accessible file (but not the return code). There is a new option called
1182            -q that suppresses the output of matching lines, which was what -s was
1183            previously doing.
1184    
1185        (p) Added --include and --exclude options to specify files for inclusion
1186            and exclusion when recursing.
1187    
1188    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1189        Hopefully, it now does.
1190    
1191    12. Missing cast in pcre_study().
1192    
1193    13. Added an "uninstall" target to the makefile.
1194    
1195    14. Replaced "extern" in the function prototypes in Makefile.in with
1196        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1197        world, but is set differently for Windows.
1198    
1199    15. Added a second compiling function called pcre_compile2(). The only
1200        difference is that it has an extra argument, which is a pointer to an
1201        integer error code. When there is a compile-time failure, this is set
1202        non-zero, in addition to the error test pointer being set to point to an
1203        error message. The new argument may be NULL if no error number is required
1204        (but then you may as well call pcre_compile(), which is now just a
1205        wrapper). This facility is provided because some applications need a
1206        numeric error indication, but it has also enabled me to tidy up the way
1207        compile-time errors are handled in the POSIX wrapper.
1208    
1209    16. Added VPATH=.libs to the makefile; this should help when building with one
1210        prefix path and installing with another. (Or so I'm told by someone who
1211        knows more about this stuff than I do.)
1212    
1213    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1214        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1215        match everything, including newlines. This is not POSIX-compatible, but
1216        somebody wanted the feature. From pcretest it can be activated by using
1217        both the P and the s flags.
1218    
1219    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1220    
1221    19. libpcre.pc was being incorrectly installed as executable.
1222    
1223    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1224        it now also looks for '\r' so that it will work unmodified on Windows.
1225    
1226    21. Added Google's contributed C++ wrapper to the distribution.
1227    
1228    22. Added some untidy missing memory free() calls in pcretest, to keep
1229        Electric Fence happy when testing.
1230    
1231    
1232    
1233    Version 5.0 13-Sep-04
1234    ---------------------
1235    
1236     1. Internal change: literal characters are no longer packed up into items
1237        containing multiple characters in a single byte-string. Each character
1238        is now matched using a separate opcode. However, there may be more than one
1239        byte in the character in UTF-8 mode.
1240    
1241     2. The pcre_callout_block structure has two new fields: pattern_position and
1242        next_item_length. These contain the offset in the pattern to the next match
1243        item, and its length, respectively.
1244    
1245     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1246        insertion of callouts before each pattern item. Added the /C option to
1247        pcretest to make use of this.
1248    
1249     4. On the advice of a Windows user, the lines
1250    
1251          #if defined(_WIN32) || defined(WIN32)
1252          _setmode( _fileno( stdout ), 0x8000 );
1253          #endif  /* defined(_WIN32) || defined(WIN32) */
1254    
1255        have been added to the source of pcretest. This apparently does useful
1256        magic in relation to line terminators.
1257    
1258     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1259        for the benefit of those environments where the "b" makes a difference.
1260    
1261     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1262        to know about it. I have put a hack into configure.in that adds in code
1263        to set GCC=yes if CC=icc. This seems to end up at a point in the
1264        generated configure script that is early enough to affect the setting of
1265        compiler options, which is what is needed, but I have no means of testing
1266        whether it really works. (The user who reported this had patched the
1267        generated configure script, which of course I cannot do.)
1268    
1269        LATER: After change 22 below (new libtool files), the configure script
1270        seems to know about icc (and also ecc). Therefore, I have commented out
1271        this hack in configure.in.
1272    
1273     7. Added support for pkg-config (2 patches were sent in).
1274    
1275     8. Negated POSIX character classes that used a combination of internal tables
1276        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1277        [[:^ascii]]. Typically, they would match almost any characters. The other
1278        POSIX classes were not broken in this way.
1279    
1280     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1281        to find the match, as PCRE was deluded into thinking that the match had to
1282        start at the start point or following a newline. The same bug applied to
1283        patterns with negative forward assertions or any backward assertions
1284        preceding ".*" at the start, unless the pattern required a fixed first
1285        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1286    
1287    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1288        starting at the last subject character, bytes beyond the end of the subject
1289        string were read.
1290    
1291    11. Renamed the variable "class" as "classbits" to make life easier for C++
1292        users. (Previously there was a macro definition, but it apparently wasn't
1293        enough.)
1294    
1295    12. Added the new field "tables" to the extra data so that tables can be passed
1296        in at exec time, or the internal tables can be re-selected. This allows
1297        a compiled regex to be saved and re-used at a later time by a different
1298        program that might have everything at different addresses.
1299    
1300    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1301        -R library as well as a -L library.
1302    
1303    14. The debugging options of pcretest (-d on the command line or D on a
1304        pattern) showed incorrect output for anything following an extended class
1305        that contained multibyte characters and which was followed by a quantifier.
1306    
1307    15. Added optional support for general category Unicode character properties
1308        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1309        support. It adds about 90K to the size of the library. The meanings of the
1310        inbuilt class escapes such as \d and \s have NOT been changed.
1311    
1312    16. Updated pcredemo.c to include calls to free() to release the memory for the
1313        compiled pattern.
1314    
1315    17. The generated file chartables.c was being created in the source directory
1316        instead of in the building directory. This caused the build to fail if the
1317        source directory was different from the building directory, and was
1318        read-only.
1319    
1320    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1321        file. No doubt somebody will tell me if they don't make sense... Also added
1322        Dan Mooney's comments about building on OpenVMS.
1323    
1324    19. Added support for partial matching via the PCRE_PARTIAL option for
1325        pcre_exec() and the \P data escape in pcretest.
1326    
1327    20. Extended pcretest with 3 new pattern features:
1328    
1329        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1330              write the compiled pattern to the file whose name is "rest-of-line".
1331              This is a straight binary dump of the data, with the saved pointer to
1332              the character tables forced to be NULL. The study data, if any, is
1333              written too. After writing, pcretest reads a new pattern.
1334    
1335        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1336              compiled pattern from the given file. There must not be any
1337              occurrences of "<" in the file name (pretty unlikely); if there are,
1338              pcretest will instead treat the initial "<" as a pattern delimiter.
1339              After reading in the pattern, pcretest goes on to read data lines as
1340              usual.
1341    
1342        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1343              and 16-bit fields in a compiled pattern, to simulate a pattern that
1344              was compiled on a host of opposite endianness.
1345    
1346    21. The pcre-exec() function can now cope with patterns that were compiled on
1347        hosts of opposite endianness, with this restriction:
1348    
1349          As for any compiled expression that is saved and used later, the tables
1350          pointer field cannot be preserved; the extra_data field in the arguments
1351          to pcre_exec() should be used to pass in a tables address if a value
1352          other than the default internal tables were used at compile time.
1353    
1354    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1355        now diagnosed as an error. Previously, most of the time, a negative number
1356        would have been treated as zero, but if in addition "ovector" was passed as
1357        NULL, a crash could occur.
1358    
1359    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1360        new versions from the libtool 1.5 distribution (the last one is a copy of
1361        a file called libtool.m4). This seems to have fixed the need to patch
1362        "configure" to support Darwin 1.3 (which I used to do). However, I still
1363        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1364        workstation).
1365    
1366    24. Changed the PCRE licence to be the more standard "BSD" licence.
1367    
1368    
1369    Version 4.5 01-Dec-03
1370    ---------------------
1371    
1372     1. There has been some re-arrangement of the code for the match() function so
1373        that it can be compiled in a version that does not call itself recursively.
1374        Instead, it keeps those local variables that need separate instances for
1375        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1376        needs to "recurse". Keeping track of where control must go is done by means
1377        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1378        hide most of the details from the main code, and operates only if
1379        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1380        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1381        operating.
1382    
1383        To make it easier for callers to provide specially tailored get/free
1384        functions for this usage, two new functions, pcre_stack_malloc, and
1385        pcre_stack_free, are used. They are always called in strict stacking order,
1386        and the size of block requested is always the same.
1387    
1388        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1389        PCRE has been compiled to use the stack or the heap for recursion. The
1390        -C option of pcretest uses this to show which version is compiled.
1391    
1392        A new data escape \S, is added to pcretest; it causes the amounts of store
1393        obtained and freed by both kinds of malloc/free at match time to be added
1394        to the output.
1395    
1396     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1397        what's available on my current Linux desktop machine.
1398    
1399     3. When matching a UTF-8 string, the test for a valid string at the start has
1400        been extended. If start_offset is not zero, PCRE now checks that it points
1401        to a byte that is the start of a UTF-8 character. If not, it returns
1402        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1403        this is necessary because there may be backward assertions in the pattern.
1404        When matching the same subject several times, it may save resources to use
1405        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1406    
1407     4. The code for checking the validity of UTF-8 strings has been tightened so
1408        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1409        containing "overlong sequences".
1410    
1411     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1412        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1413        should have been "&", but it just so happened that all the cases this let
1414        through by mistake were picked up later in the function.
1415    
1416     6. I had used a variable called "isblank" - this is a C99 function, causing
1417        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1418    
1419     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1420        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1421        so the version is shown; (c) stop "make test" echoing "./RunTest".
1422    
1423     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1424    
1425     9. The prototype for memmove() for systems that don't have it was using
1426        size_t, but the inclusion of the header that defines size_t was later. I've
1427        moved the #includes for the C headers earlier to avoid this.
1428    
1429    10. Added some adjustments to the code to make it easier to compiler on certain
1430        special systems:
1431    
1432          (a) Some "const" qualifiers were missing.
1433          (b) Added the macro EXPORT before all exported functions; by default this
1434              is defined to be empty.
1435          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1436              that it reads its output file name as an argument instead of writing
1437              to the standard output and assuming this can be redirected.
1438    
1439    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1440        class containing characters with values greater than 255, PCRE compilation
1441        went into a loop.
1442    
1443    12. A recursive reference to a subpattern that was within another subpattern
1444        that had a minimum quantifier of zero caused PCRE to crash. For example,
1445        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1446        recursion. If the recursively-called subpattern itself had a zero repeat,
1447        that was OK.
1448    
1449    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1450        buffer into which it was copied (for escape processing) was still set at
1451        1024, so long lines caused crashes.
1452    
1453    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1454        "internal error: code overflow...". This applied to any character class
1455        that was followed by a possessive quantifier.
1456    
1457    15. Modified the Makefile to add libpcre.la as a prerequisite for
1458        libpcreposix.la because I was told this is needed for a parallel build to
1459        work.
1460    
1461    16. If a pattern that contained .* following optional items at the start was
1462        studied, the wrong optimizing data was generated, leading to matching
1463        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1464        matching string must start with a or b or c. The correct conclusion for
1465        this pattern is that a match can start with any character.
1466    
1467    
1468    Version 4.4 13-Aug-03
1469    ---------------------
1470    
1471     1. In UTF-8 mode, a character class containing characters with values between
1472        127 and 255 was not handled correctly if the compiled pattern was studied.
1473        In fixing this, I have also improved the studying algorithm for such
1474        classes (slightly).
1475    
1476     2. Three internal functions had redundant arguments passed to them. Removal
1477        might give a very teeny performance improvement.
1478    
1479     3. Documentation bug: the value of the capture_top field in a callout is *one
1480        more than* the number of the hightest numbered captured substring.
1481    
1482     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1483        in incorrectly linking with a previously installed version. They now link
1484        explicitly with libpcre.la.
1485    
1486     5. configure.in no longer needs to recognize Cygwin specially.
1487    
1488     6. A problem in pcre.in for Windows platforms is fixed.
1489    
1490     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1491        pcretest, it used to include the size of the study block as part of its
1492        output. Unfortunately, the structure contains a field that has a different
1493        size on different hardware architectures. This meant that the tests that
1494        showed this size failed. As the block is currently always of a fixed size,
1495        this information isn't actually particularly useful in pcretest output, so
1496        I have just removed it.
1497    
1498     8. Three pre-processor statements accidentally did not start in column 1.
1499        Sadly, there are *still* compilers around that complain, even though
1500        standard C has not required this for well over a decade. Sigh.
1501    
1502     9. In pcretest, the code for checking callouts passed small integers in the
1503        callout_data field, which is a void * field. However, some picky compilers
1504        complained about the casts involved for this on 64-bit systems. Now
1505        pcretest passes the address of the small integer instead, which should get
1506        rid of the warnings.
1507    
1508    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1509        both compile and run time, and gives an error if an invalid UTF-8 sequence
1510        is found. There is a option for disabling this check in cases where the
1511        string is known to be correct and/or the maximum performance is wanted.
1512    
1513    11. In response to a bug report, I changed one line in Makefile.in from
1514    
1515            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1516        to
1517            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1518    
1519        to look similar to other lines, but I have no way of telling whether this
1520        is the right thing to do, as I do not use Windows. No doubt I'll get told
1521        if it's wrong...
1522    
1523    
1524    Version 4.3 21-May-03
1525    ---------------------
1526    
1527    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1528       Makefile.
1529    
1530    2. Some refactoring to improve the quality of the code:
1531    
1532       (i)   The utf8_table... variables are now declared "const".
1533    
1534       (ii)  The code for \cx, which used the "case flipping" table to upper case
1535             lower case letters, now just substracts 32. This is ASCII-specific,
1536             but the whole concept of \cx is ASCII-specific, so it seems
1537             reasonable.
1538    
1539       (iii) PCRE was using its character types table to recognize decimal and
1540             hexadecimal digits in the pattern. This is silly, because it handles
1541             only 0-9, a-f, and A-F, but the character types table is locale-
1542             specific, which means strange things might happen. A private
1543             table is now used for this - though it costs 256 bytes, a table is
1544             much faster than multiple explicit tests. Of course, the standard
1545             character types table is still used for matching digits in subject
1546             strings against \d.
1547    
1548       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1549             ending in _t are). So I've renamed it as ESC_tee.
1550    
1551    3. The first argument for regexec() in the POSIX wrapper should have been
1552       defined as "const".
1553    
1554    4. Changed pcretest to use malloc() for its buffers so that they can be
1555       Electric Fenced for debugging.
1556    
1557    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1558       to read one or more bytes before the start of the subject string. Often this
1559       had no effect on PCRE's behaviour, but in some circumstances it could
1560       provoke a segmentation fault.
1561    
1562    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1563       to try to read one or more bytes before the start of the subject string.
1564    
1565    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1566       UTF-8 support could misbehave in various ways if the subject string
1567       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1568       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1569       back over UTF-8 characters.)
1570    
1571    
1572    Version 4.2 14-Apr-03
1573    ---------------------
1574    
1575    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1576    
1577    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1578         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1579         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1580         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1581         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1582           and BUILD_EXEEXT
1583         Note: automatic setting of the BUILD variables is not yet working
1584         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1585           compile-time but not at link-time
1586         [LINK]: use for linking executables only
1587         make different versions for Windows and non-Windows
1588         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1589           libraries
1590         [LINK_FOR_BUILD]: new variable
1591         [OBJEXT]: use throughout
1592         [EXEEXT]: use throughout
1593         <winshared>: new target
1594         <wininstall>: new target
1595         <dftables.o>: use native compiler
1596         <dftables>: use native linker
1597         <install>: handle Windows platform correctly
1598         <clean>: ditto
1599         <check>: ditto
1600         copy DLL to top builddir before testing
1601    
1602       As part of these changes, -no-undefined was removed again. This was reported
1603       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1604       in any case.
1605    
1606    3. Some tidies to get rid of compiler warnings:
1607    
1608       . In the match_data structure, match_limit was an unsigned long int, whereas
1609         match_call_count was an int. I've made them both unsigned long ints.
1610    
1611       . In pcretest the fact that a const uschar * doesn't automatically cast to
1612         a void * provoked a warning.
1613    
1614       . Turning on some more compiler warnings threw up some "shadow" variables
1615         and a few more missing casts.
1616    
1617    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1618       option, a class that contained a single character with a value between 128
1619       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1620    
1621    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1622       option, a class that contained several characters, but with at least one
1623       whose value was between 128 and 255 caused PCRE to crash.
1624    
1625    
1626    Version 4.1 12-Mar-03
1627    ---------------------
1628    
1629    1. Compiling with gcc -pedantic found a couple of places where casts were
1630    needed, and a string in dftables.c that was longer than standard compilers are
1631    required to support.
1632    
1633    2. Compiling with Sun's compiler found a few more places where the code could
1634    be tidied up in order to avoid warnings.
1635    
1636    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1637    first of these names is deprecated in the latest Autoconf in favour of the name
1638    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1639    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1640    analogy I have changed it to CFLAGS_FOR_BUILD.
1641    
1642    4. Added -no-undefined to the linking command in the Makefile, because this is
1643    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1644    linking step for the pcreposix library.
1645    
1646    5. PCRE was failing to diagnose the case of two named groups with the same
1647    name.
1648    
1649    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1650    literal character that is needed in the subject for a match, and scans along to
1651    ensure that it is present before embarking on the full matching process. This
1652    saves time in cases of nested unlimited repeats that are never going to match.
1653    Problem: the scan can take a lot of time if the subject is very long (e.g.
1654    megabytes), thus penalizing straightforward matches. It is now done only if the
1655    amount of subject to be scanned is less than 1000 bytes.
1656    
1657    7. A lesser problem with the same optimization is that it was recording the
1658    first character of an anchored pattern as "needed", thus provoking a search
1659    right along the subject, even when the first match of the pattern was going to
1660    fail. The "needed" character is now not set for anchored patterns, unless it
1661    follows something in the pattern that is of non-fixed length. Thus, it still
1662    fulfils its original purpose of finding quick non-matches in cases of nested
1663    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1664    
1665    
1666    Version 4.0 17-Feb-03
1667    ---------------------
1668    
1669    1. If a comment in an extended regex that started immediately after a meta-item
1670    extended to the end of string, PCRE compiled incorrect data. This could lead to
1671    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1672    
1673    2. Moved to autoconf 2.53 and libtool 1.4.2.
1674    
1675    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1676    the special perltest8 script is no longer needed - all the tests can be run
1677    from a single perltest script.
1678    
1679    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1680    by \s. It has now been removed in PCRE. This means it isn't recognized as
1681    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1682    class [:space:] *does* include VT, thereby creating a mess.
1683    
1684    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1685    space and tab.
1686    
1687    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1688    its new features into the main test script, reducing the number of scripts.
1689    
1690    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1691    were backward compatible, and made the (?i) apply to the whole pattern, as if
1692    /i were given. Now it behaves more logically, and applies the option setting
1693    only to what follows. PCRE has been changed to follow suit. However, if it
1694    finds options settings right at the start of the pattern, it extracts them into
1695    the global options, as before. Thus, they show up in the info data.
1696    
1697    8. Added support for the \Q...\E escape sequence. Characters in between are
1698    treated as literals. This is slightly different from Perl in that $ and @ are
1699    also handled as literals inside the quotes. In Perl, they will cause variable
1700    interpolation. Note the following examples:
1701    
1702        Pattern            PCRE matches      Perl matches
1703    
1704        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1705        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1706        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1707    
1708    For compatibility with Perl, \Q...\E sequences are recognized inside character
1709    classes as well as outside them.
1710    
1711    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1712    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1713    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1714    signed/unsigned warnings.
1715    
1716    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1717    option for pcretest, so I've replaced it by a simple function that does just
1718    that job.
1719    
1720    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1721    "pcregrep -".
1722    
1723    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1724    Java package. This provides some syntactic sugar for simple cases of what my
1725    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1726    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1727    item, you can use this simplified notation. Note that only makes sense with
1728    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1729    greediness, whatever the setting of the PCRE_UNGREEDY option.
1730    
1731    13. A change of greediness default within a pattern was not taking effect at
1732    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1733    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1734    was abstracted outside.
1735    
1736    14. PCRE now supports the \G assertion. It is true when the current matching
1737    position is at the start point of the match. This differs from \A when the
1738    starting offset is non-zero. Used with the /g option of pcretest (or similar
1739    code), it works in the same way as it does for Perl's /g option. If all
1740    alternatives of a regex begin with \G, the expression is anchored to the start
1741    match position, and the "anchored" flag is set in the compiled expression.
1742    
1743    15. Some bugs concerning the handling of certain option changes within patterns
1744    have been fixed. These applied to options other than (?ims). For example,
1745    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1746    been the other way round. Some of this was related to change 7 above.
1747    
1748    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1749    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1750    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1751    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1752    
1753    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1754    mode. Unlike ".", it always matches newline, whatever the setting of
1755    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1756    assertions. Perl allows it, but it doesn't (in general) work because it can't
1757    calculate the length of the lookbehind. At least, that's the case for Perl
1758    5.8.0 - I've been told they are going to document that it doesn't work in
1759    future.
1760    
1761    18. Added an error diagnosis for escapes that PCRE does not support: these are
1762    \L, \l, \N, \P, \p, \U, \u, and \X.
1763    
1764    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1765    reading past the end of the pattern in cases such as /[abcd/.
1766    
1767    20. PCRE was getting more memory than necessary for patterns with classes that
1768    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1769    
1770    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1771    compiling PCRE for use with Virtual Pascal.
1772    
1773    22. Small fix to the Makefile to make it work properly if the build is done
1774    outside the source tree.
1775    
1776    23. Added a new extension: a condition to go with recursion. If a conditional
1777    subpattern starts with (?(R) the "true" branch is used if recursion has
1778    happened, whereas the "false" branch is used only at the top level.
1779    
1780    24. When there was a very long string of literal characters (over 255 bytes
1781    without UTF support, over 250 bytes with UTF support), the computation of how
1782    much memory was required could be incorrect, leading to segfaults or other
1783    strange effects.
1784    
1785    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1786    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1787    there was a subsequent back reference to those brackets. This meant that, for
1788    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1789    possible to check for precisely this case. All we can do is abandon the
1790    optimization if .* occurs inside capturing brackets when there are any back
1791    references whatsoever. (See below for a better fix that came later.)
1792    
1793    26. The handling of the optimization for finding the first character of a
1794    non-anchored pattern, and for finding a character that is required later in the
1795    match were failing in some cases. This didn't break the matching; it just
1796    failed to optimize when it could. The way this is done has been re-implemented.
1797    
1798    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1799    
1800    28. Added a new feature that provides some of the functionality that Perl
1801    provides with (?{...}). The facility is termed a "callout". The way it is done
1802    in PCRE is for the caller to provide an optional function, by setting
1803    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1804    global variable. By default it is unset, which disables all calling out. To get
1805    the function called, the regex must include (?C) at appropriate points. This
1806    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1807    This provides a means of identifying different callout points. When PCRE
1808    reaches such a point in the regex, if pcre_callout has been set, the external
1809    function is called. It is provided with data in a structure called
1810    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1811    matching continues; if it returns a non-zero value, the match at the current
1812    point fails. However, backtracking will occur if possible. [This was changed
1813    later and other features added - see item 49 below.]
1814    
1815    29. pcretest is upgraded to test the callout functionality. It provides a
1816    callout function that displays information. By default, it shows the start of
1817    the match and the current position in the text. There are some new data escapes
1818    to vary what happens:
1819    
1820        \C+         in addition, show current contents of captured substrings
1821        \C-         do not supply a callout function
1822        \C!n        return 1 when callout number n is reached
1823        \C!n!m      return 1 when callout number n is reached for the mth time
1824    
1825    30. If pcregrep was called with the -l option and just a single file name, it
1826    output "<stdin>" if a match was found, instead of the file name.
1827    
1828    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1829    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1830    pcre_exec(). This saves a malloc/free per call. The default value of
1831    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1832    when configuring.
1833    
1834    32. The default maximum size of a compiled pattern is 64K. There have been a
1835    few cases of people hitting this limit. The code now uses macros to handle the
1836    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1837    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1838    configuring. Tests 2 and 5 work only with 2-byte links because they output
1839    debugging information about compiled patterns.
1840    
1841    33. Internal code re-arrangements:
1842    
1843    (a) Moved the debugging function for printing out a compiled regex into
1844        its own source file (printint.c) and used #include to pull it into
1845        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1846        separate copies.
1847    
1848    (b) Defined the list of op-code names for debugging as a macro in
1849        internal.h so that it is next to the definition of the opcodes.
1850    
1851    (c) Defined a table of op-code lengths for simpler skipping along compiled
1852        code. This is again a macro in internal.h so that it is next to the
1853        definition of the opcodes.
1854    
1855    34. Added support for recursive calls to individual subpatterns, along the
1856    lines of Robin Houston's patch (but implemented somewhat differently).
1857    
1858    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1859    allow it to read and process whole directories in Win32. This code was
1860    contributed by Lionel Fourquaux; it has not been tested by me.
1861    
1862    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
1863    used to name a group. Names consist of alphanumerics and underscores, and must
1864    be unique. Back references use the syntax (?P=name) and recursive calls use
1865    (?P>name) which is a PCRE extension to the Python extension. Groups still have
1866    numbers. The function pcre_fullinfo() can be used after compilation to extract
1867    a name/number map. There are three relevant calls:
1868    
1869      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
1870      PCRE_INFO_NAMECOUNT            yields the number of entries
1871      PCRE_INFO_NAMETABLE            yields a pointer to the map.
1872    
1873    The map is a vector of fixed-size entries. The size of each entry depends on
1874    the length of the longest name used. The first two bytes of each entry are the
1875    group number, most significant byte first. There follows the corresponding
1876    name, zero terminated. The names are in alphabetical order.
1877    
1878    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
1879    case instead of 255. Making it the same both with and without UTF-8 support
1880    means that the same test output works with both.
1881    
1882    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
1883    calling malloc() with a zero argument.
1884    
1885    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
1886    optimization. I've improved things by keeping a bitmap of backreferences with
1887    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
1888    fact referenced, the optimization can be applied. It is unlikely that a
1889    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
1890    the match to follow \n) will appear inside brackets with a number greater than
1891    31, but if it does, any back reference > 31 suppresses the optimization.
1892    
1893    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
1894    of disabling numbered capturing parentheses. Any opening parenthesis that is
1895    not followed by ? behaves as if it were followed by ?: but named parentheses
1896    can still be used for capturing (and they will acquire numbers in the usual
1897    way).
1898    
1899    41. Redesigned the return codes from the match() function into yes/no/error so
1900    that errors can be passed back from deep inside the nested calls. A malloc
1901    failure while inside a recursive subpattern call now causes the
1902    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
1903    
1904    42. It is now possible to set a limit on the number of times the match()
1905    function is called in a call to pcre_exec(). This facility makes it possible to
1906    limit the amount of recursion and backtracking, though not in a directly
1907    obvious way, because the match() function is used in a number of different
1908    circumstances. The count starts from zero for each position in the subject
1909    string (for non-anchored patterns). The default limit is, for compatibility, a
1910    large number, namely 10 000 000. You can change this in two ways:
1911    
1912    (a) When configuring PCRE before making, you can use --with-match-limit=n
1913        to set a default value for the compiled library.
1914    
1915    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
1916        a different value is set. See 45 below.
1917    
1918    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
1919    
1920    43. Added a new function pcre_config(int, void *) to enable run-time extraction
1921    of things that can be changed at compile time. The first argument specifies
1922    what is wanted and the second points to where the information is to be placed.
1923    The current list of available information is:
1924    
1925      PCRE_CONFIG_UTF8
1926    
1927    The output is an integer that is set to one if UTF-8 support is available;
1928    otherwise it is set to zero.
1929    
1930      PCRE_CONFIG_NEWLINE
1931    
1932    The output is an integer that it set to the value of the code that is used for
1933    newline. It is either LF (10) or CR (13).
1934    
1935      PCRE_CONFIG_LINK_SIZE
1936    
1937    The output is an integer that contains the number of bytes used for internal
1938    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
1939    
1940      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
1941    
1942    The output is an integer that contains the threshold above which the POSIX
1943    interface uses malloc() for output vectors. See item 31 above.
1944    
1945      PCRE_CONFIG_MATCH_LIMIT
1946    
1947    The output is an unsigned integer that contains the default limit of the number
1948    of match() calls in a pcre_exec() execution. See 42 above.
1949    
1950    44. pcretest has been upgraded by the addition of the -C option. This causes it
1951    to extract all the available output from the new pcre_config() function, and to
1952    output it. The program then exits immediately.
1953    
1954    45. A need has arisen to pass over additional data with calls to pcre_exec() in
1955    order to support additional features. One way would have been to define
1956    pcre_exec2() (for example) with extra arguments, but this would not have been
1957    extensible, and would also have required all calls to the original function to
1958    be mapped to the new one. Instead, I have chosen to extend the mechanism that
1959    is used for passing in "extra" data from pcre_study().
1960    
1961    The pcre_extra structure is now exposed and defined in pcre.h. It currently
1962    contains the following fields:
1963    
1964      flags         a bitmap indicating which of the following fields are set
1965      study_data    opaque data from pcre_study()
1966      match_limit   a way of specifying a limit on match() calls for a specific
1967                      call to pcre_exec()
1968      callout_data  data for callouts (see 49 below)
1969    
1970    The flag bits are also defined in pcre.h, and are
1971    
1972      PCRE_EXTRA_STUDY_DATA
1973      PCRE_EXTRA_MATCH_LIMIT
1974      PCRE_EXTRA_CALLOUT_DATA
1975    
1976    The pcre_study() function now returns one of these new pcre_extra blocks, with
1977    the actual study data pointed to by the study_data field, and the
1978    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
1979    before. That is, this change is entirely upwards-compatible and requires no
1980    change to existing code.
1981    
1982    If you want to pass in additional data to pcre_exec(), you can either place it
1983    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
1984    block.
1985    
1986    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
1987    data string contains the escape sequence \M, pcretest calls pcre_exec() several
1988    times with different match limits, until it finds the minimum value needed for
1989    pcre_exec() to complete. The value is then output. This can be instructive; for
1990    most simple matches the number is quite small, but for pathological cases it
1991    gets very large very quickly.
1992    
1993    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
1994    returns the size of the data block pointed to by the study_data field in a
1995    pcre_extra block, that is, the value that was passed as the argument to
1996    pcre_malloc() when PCRE was getting memory in which to place the information
1997    created by pcre_study(). The fourth argument should point to a size_t variable.
1998    pcretest has been extended so that this information is shown after a successful
1999    pcre_study() call when information about the compiled regex is being displayed.
2000    
2001    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2002    because what follows is always an absolute path. (Later: it turns out that this
2003    is more than cosmetic for MinGW, because it doesn't like empty path
2004    components.)
2005    
2006    49. Some changes have been made to the callout feature (see 28 above):
2007    
2008    (i)  A callout function now has three choices for what it returns:
2009    
2010           0  =>  success, carry on matching
2011         > 0  =>  failure at this point, but backtrack if possible
2012         < 0  =>  serious error, return this value from pcre_exec()
2013    
2014         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2015         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2016         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2017         use by callout functions. It will never be used by PCRE itself.
2018    
2019    (ii) The pcre_extra structure (see 45 above) has a void * field called
2020         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2021         pcre_callout_block structure has a field of the same name. The contents of
2022         the field passed in the pcre_extra structure are passed to the callout
2023         function in the corresponding field in the callout block. This makes it
2024         easier to use the same callout-containing regex from multiple threads. For
2025         testing, the pcretest program has a new data escape
2026    
2027           \C*n        pass the number n (may be negative) as callout_data
2028    
2029         If the callout function in pcretest receives a non-zero value as
2030         callout_data, it returns that value.
2031    
2032    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2033    there were some redundant $(CFLAGS) in commands that are now specified as
2034    $(LINK), which already includes $(CFLAGS).
2035    
2036    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2037    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2038    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2039    one-byte characters throughout. Note that case-insensitive matching applies
2040    only to characters whose values are less than 256. PCRE doesn't support the
2041    notion of cases for higher-valued characters.
2042    
2043    (i)   A character class whose characters are all within 0-255 is handled as
2044          a bit map, and the map is inverted for negative classes. Previously, a
2045          character > 255 always failed to match such a class; however it should
2046          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2047    
2048    (ii)  A negated character class with a single character < 255 is coded as
2049          "not this character" (OP_NOT). This wasn't working properly when the test
2050          character was multibyte, either singly or repeated.
2051    
2052    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2053          mode, for example: \x{100}{2,3}.
2054    
2055    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2056          singly or repeated) now correctly test multibyte characters. However,
2057          PCRE doesn't recognize any characters with values greater than 255 as
2058          digits, spaces, or word characters. Such characters always match \D, \S,
2059          and \W, and never match \d, \s, or \w.
2060    
2061    (v)   Classes may now contain characters and character ranges with values
2062          greater than 255. For example: [ab\x{100}-\x{400}].
2063    
2064    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2065          PCRE in UTF-8 mode.
2066    
2067    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2068    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2069    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2070    value.)
2071    
2072    53. The single man page has become too large. I have therefore split it up into
2073    a number of separate man pages. These also give rise to individual HTML pages;
2074    these are now put in a separate directory, and there is an index.html page that
2075    lists them all. Some hyperlinking between the pages has been installed.
2076    
2077    54. Added convenience functions for handling named capturing parentheses.
2078    
2079    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2080    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2081    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2082    are faulted.
2083    
2084    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2085    calling configure. These values are used when compiling the dftables.c program
2086    which is run to generate the source of the default character tables. They
2087    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2088    you will need to set these values.
2089    
2090    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2091    
2092    
2093    Version 3.9 02-Jan-02
2094    ---------------------
2095    
2096    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2097    
2098    2. If --disable-static was given, the building process failed when trying to
2099    build pcretest and pcregrep. (For some reason it was using libtool to compile
2100    them, which is not right, as they aren't part of the library.)
2101    
2102    
2103    Version 3.8 18-Dec-01
2104    ---------------------
2105    
2106    1. The experimental UTF-8 code was completely screwed up. It was packing the
2107    bytes in the wrong order. How dumb can you get?
2108    
2109    
2110    Version 3.7 29-Oct-01
2111    ---------------------
2112    
2113    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2114    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2115    this didn't happen under Solaris 8, where I normally test things.
2116    
2117    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2118    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2119    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2120    this fix an hour or so after the initial 3.7 release.)
2121    
2122    
2123    Version 3.6 23-Oct-01
2124    ---------------------
2125    
2126    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2127    offsets passed as NULL with zero offset count.
2128    
2129    2. The config.guess and config.sub files had not been updated when I moved to
2130    the latest autoconf.
2131    
2132    
2133    Version 3.5 15-Aug-01
2134    ---------------------
2135    
2136    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2137    had been forgotten.
2138    
2139    2. By using declared but undefined structures, we can avoid using "void"
2140    definitions in pcre.h while keeping the internal definitions of the structures
2141    private.
2142    
2143    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2144    user point of view, this means that both static and shared libraries are built
2145    by default, but this can be individually controlled. More of the work of
2146    handling this static/shared cases is now inside libtool instead of PCRE's make
2147    file.
2148    
2149    4. The pcretest utility is now installed along with pcregrep because it is
2150    useful for users (to test regexs) and by doing this, it automatically gets
2151    relinked by libtool. The documentation has been turned into a man page, so
2152    there are now .1, .txt, and .html versions in /doc.
2153    
2154    5. Upgrades to pcregrep:
2155       (i)   Added long-form option names like gnu grep.
2156       (ii)  Added --help to list all options with an explanatory phrase.
2157       (iii) Added -r, --recursive to recurse into sub-directories.
2158       (iv)  Added -f, --file to read patterns from a file.
2159    
2160    6. pcre_exec() was referring to its "code" argument before testing that
2161    argument for NULL (and giving an error if it was NULL).
2162    
2163    7. Upgraded Makefile.in to allow for compiling in a different directory from
2164    the source directory.
2165    
2166    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2167    options bits, the pointer it was passed was to an int instead of to an unsigned
2168    long int. This mattered only on 64-bit systems.
2169    
2170    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2171    generated) instead of pcre.in, which it its source. Also made the same change
2172    in several of the .c files.
2173    
2174    10. A new release of gcc defines printf() as a macro, which broke pcretest
2175    because it had an ifdef in the middle of a string argument for printf(). Fixed
2176    by using separate calls to printf().
2177    
2178    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2179    script, to force use of CR or LF instead of \n in the source. On non-Unix
2180    systems, the value can be set in config.h.
2181    
2182    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2183    absolute limit. Changed the text of the error message to make this clear, and
2184    likewise updated the man page.
2185    
2186    13. The limit of 99 on the number of capturing subpatterns has been removed.
2187    The new limit is 65535, which I hope will not be a "real" limit.
2188    
2189    
2190    Version 3.4 22-Aug-00
2191    ---------------------
2192    
2193    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2194    
2195    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2196    
2197    
2198    Version 3.3 01-Aug-00
2199    ---------------------
2200    
2201    1. If an octal character was given, but the value was greater than \377, it
2202    was not getting masked to the least significant bits, as documented. This could
2203    lead to crashes in some systems.
2204    
2205    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2206    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2207    
2208    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2209    These just pass their arguments on to (pcre_free)(), but they are provided
2210    because some uses of PCRE bind it to non-C systems that can call its functions,
2211    but cannot call free() or pcre_free() directly.
2212    
2213    4. Add "make test" as a synonym for "make check". Corrected some comments in
2214    the Makefile.
2215    
2216    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2217    Makefile.
2218    
2219    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2220    command called pgrep for grepping around the active processes.
2221    
2222    7. Added the beginnings of support for UTF-8 character strings.
2223    
2224    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2225    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2226    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2227    out for the ar command.)
2228    
2229    
2230    Version 3.2 12-May-00
2231    ---------------------
2232    
2233    This is purely a bug fixing release.
2234    
2235    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2236    of ZA. This was just one example of several cases that could provoke this bug,
2237    which was introduced by change 9 of version 2.00. The code for breaking
2238    infinite loops after an iteration that matches an empty string was't working
2239    correctly.
2240    
2241    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2242    when matched against abbab (for example). After matching an empty string, it
2243    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2244    caused it to match further down the string than it should.
2245    
2246    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2247    was there because it doesn't seem to be needed, and it causes trouble on some
2248    systems, as it is not a Standard C header. It has been removed.
2249    
2250    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2251    were reported on the Macintosh. The changes were from
2252    
2253      while ((c = *(++ptr)) != 0 && c != '\n');
2254    to
2255      while ((c = *(++ptr)) != 0 && c != '\n') ;
2256    
2257    Totally extraordinary, but if that's what it takes...
2258    
2259    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2260    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2261    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2262    assumes the way PCRE uses memmove() (always moving upwards).
2263    
2264    6. PCRE is being used in one environment where strchr() is not available. There
2265    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2266    faster code anyway.
2267    
2268    
2269    Version 3.1 09-Feb-00
2270    ---------------------
2271    
2272    The only change in this release is the fixing of some bugs in Makefile.in for
2273    the "install" target:
2274    
2275    (1) It was failing to install pcreposix.h.
2276    
2277    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2278    
2279    
2280    Version 3.0 01-Feb-00
2281    ---------------------
2282    
2283    1. Add support for the /+ modifier to perltest (to output $` like it does in
2284    pcretest).
2285    
2286    2. Add support for the /g modifier to perltest.
2287    
2288    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2289    matches null strings.
2290    
2291    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2292    pattern. Perl treats empty patterns specially - it reuses the most recent
2293    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2294    effect.
2295    
2296    5. The POSIX interface was broken in that it was just handing over the POSIX
2297    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2298    required a bigger vector, with some working space on the end. This means that
2299    the POSIX wrapper now has to get and free some memory, and copy the results.
2300    
2301    6. Added some simple autoconf support, placing the test data and the
2302    documentation in separate directories, re-organizing some of the
2303    information files, and making it build pcre-config (a GNU standard). Also added
2304    libtool support for building PCRE as a shared library, which is now the
2305    default.
2306    
2307    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2308    09 are not valid octal constants. Single digits will be used for minor values
2309    less than 10.
2310    
2311    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2312    existing programs that set these in the POSIX interface can use PCRE without
2313    modification.
2314    
2315    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2316    return all that pcre_info() returns, plus additional data. The pcre_info()
2317    function is retained for compatibility, but is considered to be obsolete.
2318    
2319    10. Added experimental recursion feature (?R) to handle one common case that
2320    Perl 5.6 will be able to do with (?p{...}).
2321    
2322    11. Added support for POSIX character classes like [:alpha:], which Perl is
2323    adopting.
2324    
2325    
2326    Version 2.08 31-Aug-99
2327    ----------------------
2328    
2329    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2330    trying to match at the startoffset position, but instead was moving forward to
2331    the next newline as if a previous match had failed.
2332    
2333    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2334    and could get into a loop if a null string was matched other than at the start
2335    of the subject.
2336    
2337    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2338    be distinguished at compile time, and for completeness also added PCRE_DATE.
2339    
2340    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2341    in GnuWin32 environments.
2342    
2343    
2344    Version 2.07 29-Jul-99
2345    ----------------------
2346    
2347    1. The documentation is now supplied in plain text form and HTML as well as in
2348    the form of man page sources.
2349    
2350    2. C++ compilers don't like assigning (void *) values to other pointer types.
2351    In particular this affects malloc(). Although there is no problem in Standard
2352    C, I've put in casts to keep C++ compilers happy.
2353    
2354    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2355    should be (const char *).
2356    
2357    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2358    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2359    However, I haven't made this a standard facility. The documentation doesn't
2360    mention it, and the Makefile doesn't support it.
2361    
2362    5. The Makefile now contains an "install" target, with editable destinations at
2363    the top of the file. The pcretest program is not installed.
2364    
2365    6. pgrep -V now gives the PCRE version number and date.
2366    
2367    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2368    causing the entire string to be ignored, instead of just the last character.
2369    
2370    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2371    non-matching string, it can take a very, very long time, even for strings of
2372    quite modest length, because of the nested recursion. PCRE now does better in
2373    some of these cases. It does this by remembering the last required literal
2374    character in the pattern, and pre-searching the subject to ensure it is present
2375    before running the real match. In other words, it applies a heuristic to detect
2376    some types of certain failure quickly, and in the above example, if presented
2377    with a string that has no trailing " it gives "no match" very quickly.
2378    
2379    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2380    other alternatives are tried instead.
2381    
2382    
2383    Version 2.06 09-Jun-99
2384    ----------------------
2385    
2386    1. Change pcretest's output for amount of store used to show just the code
2387    space, because the remainder (the data block) varies in size between 32-bit and
2388    64-bit systems.
2389    
2390    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2391    start matching at. This allows lookbehinds to work when searching for multiple
2392    occurrences in a string.
2393    
2394    3. Added additional options to pcretest for testing multiple occurrences:
2395    
2396       /+   outputs the rest of the string that follows a match
2397       /g   loops for multiple occurrences, using the new startoffset argument
2398       /G   loops for multiple occurrences by passing an incremented pointer
2399    
2400    4. PCRE wasn't doing the "first character" optimization for patterns starting
2401    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2402    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2403    the letter 'x'. On long subject strings, this gives a significant speed-up.
2404    
2405    
2406    Version 2.05 21-Apr-99
2407    ----------------------
2408    
2409    1. Changed the type of magic_number from int to long int so that it works
2410    properly on 16-bit systems.
2411    
2412    2. Fixed a bug which caused patterns starting with .* not to work correctly
2413    when the subject string contained newline characters. PCRE was assuming
2414    anchoring for such patterns in all cases, which is not correct because .* will
2415    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2416    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2417    must be retried after every newline in the subject.
2418    
2419    
2420    Version 2.04 18-Feb-99
2421    ----------------------
2422    
2423    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2424    computation of the store needed to hold the pattern was incorrect (too large).
2425    If such patterns were nested a few deep, this could multiply and become a real
2426    problem.
2427    
2428    2. Added /M option to pcretest to show the memory requirement of a specific
2429    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2430    
2431    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2432    compiled in such a way that the backtracking after subsequent failure was
2433    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2434    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2435    
2436    
2437    Version 2.03 02-Feb-99
2438    ----------------------
2439    
2440    1. Fixed typo and small mistake in man page.
2441    
2442    2. Added 4th condition (GPL supersedes if conflict) and created separate
2443    LICENCE file containing the conditions.
2444    
2445    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2446    Perl, that is the internal \ allows the delimiter to be included in the
2447    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2448    the final delimiter, add \ to the end of the pattern (to test the error).
2449    
2450    4. Added the convenience functions for extracting substrings after a successful
2451    match. Updated pcretest to make it able to test these functions.
2452    
2453    
2454    Version 2.02 14-Jan-99
2455    ----------------------
2456    
2457    1. Initialized the working variables associated with each extraction so that
2458    their saving and restoring doesn't refer to uninitialized store.
2459    
2460    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2461    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2462    fix the problem.
2463    
2464    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2465    calls, and wasn't printing the correct value for compiling calls. Increased the
2466    default value of LOOPREPEAT, and the number of significant figures in the
2467    times.
2468    
2469    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2470    
2471    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2472    a building problem on Windows NT with a FAT file system.
2473    
2474    
2475    Version 2.01 21-Oct-98
2476    ----------------------
2477    
2478    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2479    to character tables built by pcre_maketables() in the current locale. If NULL
2480    is passed, the default tables are used.
2481    
2482    
2483  Version 2.00 24-Sep-98  Version 2.00 24-Sep-98
2484  ----------------------  ----------------------

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