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revision 83 by nigel, Sat Feb 24 21:41:06 2007 UTC revision 245 by ph10, Fri Sep 14 10:06:05 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.4 10-Sep-07
5    ---------------------
6    
7    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8        means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
13    
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
19    
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
25    
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
28    
29    5.  doc/pcresyntax.html was missing from the distribution.
30    
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
33    
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 (where
36        different names are used).
37    
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
40    
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
43    
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
49    
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
55    
56        Thanks to the folks working on Gregex for glib for this insight.
57    
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
60    
61    12. Updated the RunTest script to miss out tests that don't work if \R is
62        defaulted to ANYCRLF.
63    
64    
65    Version 7.3 28-Aug-07
66    ---------------------
67    
68     1. In the rejigging of the build system that eventually resulted in 7.1, the
69        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
70        brackets there is not right, since it causes compilers to look for an
71        installed pcre.h, not the version that is in the source that is being
72        compiled (which of course may be different). I have changed it back to:
73    
74          #include "pcre.h"
75    
76        I have a vague recollection that the change was concerned with compiling in
77        different directories, but in the new build system, that is taken care of
78        by the VPATH setting the Makefile.
79    
80     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
81        when the subject happened to end in the byte 0x85 (e.g. if the last
82        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
83        characters but of course it shouldn't be taken as a newline when it is part
84        of another character. The bug was that, for an unlimited repeat of . in
85        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
86        characters when looking for a newline.
87    
88     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
89    
90     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
91        in debug output.
92    
93     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
94        long printing in the pcrecpp unittest when running under MinGW.
95    
96     6. ESC_K was left out of the EBCDIC table.
97    
98     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
99        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
100        limit also applies to "virtual nesting" when a pattern is recursive, and in
101        this case 1000 isn't so big. I have been able to remove this limit at the
102        expense of backing off one optimization in certain circumstances. Normally,
103        when pcre_exec() would call its internal match() function recursively and
104        immediately return the result unconditionally, it uses a "tail recursion"
105        feature to save stack. However, when a subpattern that can match an empty
106        string has an unlimited repetition quantifier, it no longer makes this
107        optimization. That gives it a stack frame in which to save the data for
108        checking that an empty string has been matched. Previously this was taken
109        from the 1000-entry workspace that had been reserved. So now there is no
110        explicit limit, but more stack is used.
111    
112     8. Applied Daniel's patches to solve problems with the import/export magic
113        syntax that is required for Windows, and which was going wrong for the
114        pcreposix and pcrecpp parts of the library. These were overlooked when this
115        problem was solved for the main library.
116    
117     9. There were some crude static tests to avoid integer overflow when computing
118        the size of patterns that contain repeated groups with explicit upper
119        limits. As the maximum quantifier is 65535, the maximum group length was
120        set at 30,000 so that the product of these two numbers did not overflow a
121        32-bit integer. However, it turns out that people want to use groups that
122        are longer than 30,000 bytes (though not repeat them that many times).
123        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
124        made it possible to implement the integer overflow checks in a much more
125        dynamic way, which I have now done. The artificial limitation on group
126        length has been removed - we now have only the limit on the total length of
127        the compiled pattern, which depends on the LINK_SIZE setting.
128    
129    10. Fixed a bug in the documentation for get/copy named substring when
130        duplicate names are permitted. If none of the named substrings are set, the
131        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
132        empty string.
133    
134    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
135        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
136        because the ] is interpreted as the first data character and the
137        terminating ] is not found. PCRE has been made compatible with Perl in this
138        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
139        cause memory overwriting.
140    
141    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
142        string has been matched (to stop an infinite loop). It was not recognizing
143        a conditional subpattern that could match an empty string if that
144        subpattern was within another subpattern. For example, it looped when
145        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
146        condition was not nested. This bug has been fixed.
147    
148    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
149        past the start of the subject in the presence of bytes with the top bit
150        set, for example "\x8aBCD".
151    
152    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
153        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
154    
155    14. Optimized (?!) to (*FAIL).
156    
157    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
158        This restricts code points to be within the range 0 to 0x10FFFF, excluding
159        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
160        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
161        does: it's just the validity check that is more restrictive.
162    
163    16. Inserted checks for integer overflows during escape sequence (backslash)
164        processing, and also fixed erroneous offset values for syntax errors during
165        backslash processing.
166    
167    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
168        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
169    
170    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
171        caused an overrun.
172    
173    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
174        something other than just ASCII characters) inside a group that had an
175        unlimited repeat caused a loop at compile time (while checking to see
176        whether the group could match an empty string).
177    
178    20. Debugging a pattern containing \p or \P could cause a crash. For example,
179        [\P{Any}] did so. (Error in the code for printing property names.)
180    
181    21. An orphan \E inside a character class could cause a crash.
182    
183    22. A repeated capturing bracket such as (A)? could cause a wild memory
184        reference during compilation.
185    
186    23. There are several functions in pcre_compile() that scan along a compiled
187        expression for various reasons (e.g. to see if it's fixed length for look
188        behind). There were bugs in these functions when a repeated \p or \P was
189        present in the pattern. These operators have additional parameters compared
190        with \d, etc, and these were not being taken into account when moving along
191        the compiled data. Specifically:
192    
193        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
194            length.
195    
196        (b) An item such as \pL+ within a repeated group could cause crashes or
197            loops.
198    
199        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
200            "reference to non-existent subpattern" error.
201    
202        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
203    
204    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
205        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
206    
207    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
208    
209    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
210        character were causing crashes (broken optimization).
211    
212    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
213        \p or \P) caused a compile-time loop.
214    
215    28. More problems have arisen in unanchored patterns when CRLF is a valid line
216        break. For example, the unstudied pattern [\r\n]A does not match the string
217        "\r\nA" because change 7.0/46 below moves the current point on by two
218        characters after failing to match at the start. However, the pattern \nA
219        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
220        the same is true. There doesn't seem any very clean way out of this, but
221        what I have chosen to do makes the common cases work: PCRE now takes note
222        of whether there can be an explicit match for \r or \n anywhere in the
223        pattern, and if so, 7.0/46 no longer applies. As part of this change,
224        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
225        pattern has explicit CR or LF references.
226    
227    29. Added (*CR) etc for changing newline setting at start of pattern.
228    
229    
230    Version 7.2 19-Jun-07
231    ---------------------
232    
233     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
234        which is apparently normally available under Windows.
235    
236     2. Re-jig the pcregrep tests with different newline settings in an attempt
237        to make them independent of the local environment's newline setting.
238    
239     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
240    
241     4. Some of the "internals" tests were previously cut out when the link size
242        was not 2, because the output contained actual offsets. The recent new
243        "Z" feature of pcretest means that these can be cut out, making the tests
244        usable with all link sizes.
245    
246     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
247        stack recursion. This gives a massive performance boost under BSD, but just
248        a small improvement under Linux. However, it saves one field in the frame
249        in all cases.
250    
251     6. Added more features from the forthcoming Perl 5.10:
252    
253        (a) (?-n) (where n is a string of digits) is a relative subroutine or
254            recursion call. It refers to the nth most recently opened parentheses.
255    
256        (b) (?+n) is also a relative subroutine call; it refers to the nth next
257            to be opened parentheses.
258    
259        (c) Conditions that refer to capturing parentheses can be specified
260            relatively, for example, (?(-2)... or (?(+3)...
261    
262        (d) \K resets the start of the current match so that everything before
263            is not part of it.
264    
265        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
266    
267        (f) \g{name} is another synonym - part of Perl 5.10's unification of
268            reference syntax.
269    
270        (g) (?| introduces a group in which the numbering of parentheses in each
271            alternative starts with the same number.
272    
273        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
274    
275     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
276        PCRE_INFO_JCHANGED.
277    
278     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
279        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
280        for detecting groups that can match an empty string.
281    
282     9. A pattern with a very large number of alternatives (more than several
283        hundred) was running out of internal workspace during the pre-compile
284        phase, where pcre_compile() figures out how much memory will be needed. A
285        bit of new cunning has reduced the workspace needed for groups with
286        alternatives. The 1000-alternative test pattern now uses 12 bytes of
287        workspace instead of running out of the 4096 that are available.
288    
289    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
290    
291    11. Applied patch from Google to remove an optimization that didn't quite work.
292        The report of the bug said:
293    
294          pcrecpp::RE("a*").FullMatch("aaa") matches, while
295          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
296          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
297    
298    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
299        it matched the wrong number of bytes.
300    
301    
302    Version 7.1 24-Apr-07
303    ---------------------
304    
305     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
306        that is more "standard", making use of automake and other Autotools. There
307        is some re-arrangement of the files and adjustment of comments consequent
308        on this.
309    
310     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
311        for recursive directory scanning broke on some systems because the files
312        are not scanned in any specific order and on different systems the order
313        was different. A call to "sort" has been inserted into RunGrepTest for the
314        approprate test as a short-term fix. In the longer term there may be an
315        alternative.
316    
317     3. I had an email from Eric Raymond about problems translating some of PCRE's
318        man pages to HTML (despite the fact that I distribute HTML pages, some
319        people do their own conversions for various reasons). The problems
320        concerned the use of low-level troff macros .br and .in. I have therefore
321        removed all such uses from the man pages (some were redundant, some could
322        be replaced by .nf/.fi pairs). The 132html script that I use to generate
323        HTML has been updated to handle .nf/.fi and to complain if it encounters
324        .br or .in.
325    
326     4. Updated comments in configure.ac that get placed in config.h.in and also
327        arranged for config.h to be included in the distribution, with the name
328        config.h.generic, for the benefit of those who have to compile without
329        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
330    
331     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
332        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
333        makevp.bat for the current PCRE, using the additional files
334        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
335    
336     6. A Windows user reported a minor discrepancy with test 2, which turned out
337        to be caused by a trailing space on an input line that had got lost in his
338        copy. The trailing space was an accident, so I've just removed it.
339    
340     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
341        that is needed.
342    
343     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
344        as "const" (a) because they are and (b) because it helps the PHP
345        maintainers who have recently made a script to detect big data structures
346        in the php code that should be moved to the .rodata section. I remembered
347        to update Builducptable as well, so it won't revert if ucptable.h is ever
348        re-created.
349    
350     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
351        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
352        order to be able to cut out the UTF-8 tables in the latter when UTF-8
353        support is not required. This saves 1.5-2K of code, which is important in
354        some applications.
355    
356        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
357        so as not to refer to the tables, even though these functions will never be
358        called when UTF-8 support is disabled. Otherwise there are problems with a
359        shared library.
360    
361    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
362    
363        (a) It was defining its arguments as char * instead of void *.
364    
365        (b) It was assuming that all moves were upwards in memory; this was true
366            a long time ago when I wrote it, but is no longer the case.
367    
368        The emulated memove() is provided for those environments that have neither
369        memmove() nor bcopy(). I didn't think anyone used it these days, but that
370        is clearly not the case, as these two bugs were recently reported.
371    
372    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
373        and Detrail to create the HTML documentation, the .txt form of the man
374        pages, and it removes trailing spaces from listed files. It also creates
375        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
376        case, it wraps all the #defines with #ifndefs. This script should be run
377        before "make dist".
378    
379    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
380        with Unicode property support.
381    
382        (a) For a maximizing quantifier, if the two different cases of the
383            character were of different lengths in their UTF-8 codings (there are
384            some cases like this - I found 11), and the matching function had to
385            back up over a mixture of the two cases, it incorrectly assumed they
386            were both the same length.
387    
388        (b) When PCRE was configured to use the heap rather than the stack for
389            recursion during matching, it was not correctly preserving the data for
390            the other case of a UTF-8 character when checking ahead for a match
391            while processing a minimizing repeat. If the check also involved
392            matching a wide character, but failed, corruption could cause an
393            erroneous result when trying to check for a repeat of the original
394            character.
395    
396    13. Some tidying changes to the testing mechanism:
397    
398        (a) The RunTest script now detects the internal link size and whether there
399            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
400            values substituted by "configure". (The RunGrepTest script already did
401            this for UTF-8.) The configure.ac script no longer substitutes the
402            relevant variables.
403    
404        (b) The debugging options /B and /D in pcretest show the compiled bytecode
405            with length and offset values. This means that the output is different
406            for different internal link sizes. Test 2 is skipped for link sizes
407            other than 2 because of this, bypassing the problem. Unfortunately,
408            there was also a test in test 3 (the locale tests) that used /B and
409            failed for link sizes other than 2. Rather than cut the whole test out,
410            I have added a new /Z option to pcretest that replaces the length and
411            offset values with spaces. This is now used to make test 3 independent
412            of link size. (Test 2 will be tidied up later.)
413    
414    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
415        segmentation fault instead of returning the appropriate error message.
416    
417    15. In multiline mode when the newline sequence was set to "any", the pattern
418        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
419        This doesn't seem right; it now treats the CRLF combination as the line
420        ending, and so does not match in that case. It's only a pattern such as ^$
421        that would hit this one: something like ^ABC$ would have failed after \r
422        and then tried again after \r\n.
423    
424    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
425        in an attempt to make files that differ only in their line terminators
426        compare equal. This works on Linux.
427    
428    17. Under certain error circumstances pcregrep might try to free random memory
429        as it exited. This is now fixed, thanks to valgrind.
430    
431    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
432        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
433        was because its rules for how to advance for /g after matching an empty
434        string at the end of a line did not allow for this case. They now check for
435        it specially.
436    
437    20. pcretest is supposed to handle patterns and data of any length, by
438        extending its buffers when necessary. It was getting this wrong when the
439        buffer for a data line had to be extended.
440    
441    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
442        CRLF as a newline sequence.
443    
444    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
445        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
446        I have nevertheless tidied it up.
447    
448    23. Added some casts to kill warnings from HP-UX ia64 compiler.
449    
450    24. Added a man page for pcre-config.
451    
452    
453    Version 7.0 19-Dec-06
454    ---------------------
455    
456     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
457        moving to gcc 4.1.1.
458    
459     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
460        sys/time.h, which is documented as needed for this function. It doesn't
461        seem to matter on Linux, but it showed up on some releases of OS X.
462    
463     3. It seems that there are systems where bytes whose values are greater than
464        127 match isprint() in the "C" locale. The "C" locale should be the
465        default when a C program starts up. In most systems, only ASCII printing
466        characters match isprint(). This difference caused the output from pcretest
467        to vary, making some of the tests fail. I have changed pcretest so that:
468    
469        (a) When it is outputting text in the compiled version of a pattern, bytes
470            other than 32-126 are always shown as hex escapes.
471    
472        (b) When it is outputting text that is a matched part of a subject string,
473            it does the same, unless a different locale has been set for the match
474            (using the /L modifier). In this case, it uses isprint() to decide.
475    
476     4. Fixed a major bug that caused incorrect computation of the amount of memory
477        required for a compiled pattern when options that changed within the
478        pattern affected the logic of the preliminary scan that determines the
479        length. The relevant options are -x, and -i in UTF-8 mode. The result was
480        that the computed length was too small. The symptoms of this bug were
481        either the PCRE error "internal error: code overflow" from pcre_compile(),
482        or a glibc crash with a message such as "pcretest: free(): invalid next
483        size (fast)". Examples of patterns that provoked this bug (shown in
484        pcretest format) are:
485    
486          /(?-x: )/x
487          /(?x)(?-x: \s*#\s*)/
488          /((?i)[\x{c0}])/8
489          /(?i:[\x{c0}])/8
490    
491        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
492        is now done differently.
493    
494     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
495        wrapper classes; (b) implement a new function in the C++ scanner that is
496        more efficient than the old way of doing things because it avoids levels of
497        recursion in the regex matching; (c) add a paragraph to the documentation
498        for the FullMatch() function.
499    
500     6. The escape sequence \n was being treated as whatever was defined as
501        "newline". Not only was this contrary to the documentation, which states
502        that \n is character 10 (hex 0A), but it also went horribly wrong when
503        "newline" was defined as CRLF. This has been fixed.
504    
505     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
506        was being set to -1 for the "end of line" case (supposedly a value that no
507        character can have). Though this value is never used (the check for end of
508        line is "zero bytes in current character"), it caused compiler complaints.
509        I've changed it to 0xffffffff.
510    
511     8. In pcre_version.c, the version string was being built by a sequence of
512        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
513        string (as it is for production releases) called a macro with an empty
514        argument. The C standard says the result of this is undefined. The gcc
515        compiler treats it as an empty string (which was what was wanted) but it is
516        reported that Visual C gives an error. The source has been hacked around to
517        avoid this problem.
518    
519     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
520        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
521        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
522        of them did).
523    
524    10. Originally, pcretest opened its input and output without "b"; then I was
525        told that "b" was needed in some environments, so it was added for release
526        5.0 to both the input and output. (It makes no difference on Unix-like
527        systems.) Later I was told that it is wrong for the input on Windows. I've
528        now abstracted the modes into two macros, to make it easier to fiddle with
529        them, and removed "b" from the input mode under Windows.
530    
531    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
532    
533    12. Added -help and --help to pcretest as an official way of being reminded
534        of the options.
535    
536    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
537        and pcrecpp.cc because they annoy compilers at high warning levels.
538    
539    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
540    
541    15. Fixed an occurrence of == in configure.ac that should have been = (shell
542        scripts are not C programs :-) and which was not noticed because it works
543        on Linux.
544    
545    16. pcretest is supposed to handle any length of pattern and data line (as one
546        line or as a continued sequence of lines) by extending its input buffer if
547        necessary. This feature was broken for very long pattern lines, leading to
548        a string of junk being passed to pcre_compile() if the pattern was longer
549        than about 50K.
550    
551    17. I have done a major re-factoring of the way pcre_compile() computes the
552        amount of memory needed for a compiled pattern. Previously, there was code
553        that made a preliminary scan of the pattern in order to do this. That was
554        OK when PCRE was new, but as the facilities have expanded, it has become
555        harder and harder to keep it in step with the real compile phase, and there
556        have been a number of bugs (see for example, 4 above). I have now found a
557        cunning way of running the real compile function in a "fake" mode that
558        enables it to compute how much memory it would need, while actually only
559        ever using a few hundred bytes of working memory and without too many
560        tests of the mode. This should make future maintenance and development
561        easier. A side effect of this work is that the limit of 200 on the nesting
562        depth of parentheses has been removed (though this was never a serious
563        limitation, I suspect). However, there is a downside: pcre_compile() now
564        runs more slowly than before (30% or more, depending on the pattern). I
565        hope this isn't a big issue. There is no effect on runtime performance.
566    
567    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
568        newline (only possible for the last line of a file) and it was a
569        pattern that set a locale (followed by /Lsomething), pcretest crashed.
570    
571    19. Added additional timing features to pcretest. (1) The -tm option now times
572        matching only, not compiling. (2) Both -t and -tm can be followed, as a
573        separate command line item, by a number that specifies the number of
574        repeats to use when timing. The default is 50000; this gives better
575        precision, but takes uncomfortably long for very large patterns.
576    
577    20. Extended pcre_study() to be more clever in cases where a branch of a
578        subpattern has no definite first character. For example, (a*|b*)[cd] would
579        previously give no result from pcre_study(). Now it recognizes that the
580        first character must be a, b, c, or d.
581    
582    21. There was an incorrect error "recursive call could loop indefinitely" if
583        a subpattern (or the entire pattern) that was being tested for matching an
584        empty string contained only one non-empty item after a nested subpattern.
585        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
586        incorrectly, because the \d was being skipped in the check.
587    
588    22. The pcretest program now has a new pattern option /B and a command line
589        option -b, which is equivalent to adding /B to every pattern. This causes
590        it to show the compiled bytecode, without the additional information that
591        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
592        is the same as /B/I).
593    
594    23. A new optimization is now able automatically to treat some sequences such
595        as a*b as a*+b. More specifically, if something simple (such as a character
596        or a simple class like \d) has an unlimited quantifier, and is followed by
597        something that cannot possibly match the quantified thing, the quantifier
598        is automatically "possessified".
599    
600    24. A recursive reference to a subpattern whose number was greater than 39
601        went wrong under certain circumstances in UTF-8 mode. This bug could also
602        have affected the operation of pcre_study().
603    
604    25. Realized that a little bit of performance could be had by replacing
605        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
606    
607    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
608    
609    27. Possessive quantifiers such as a++ were previously implemented by turning
610        them into atomic groups such as ($>a+). Now they have their own opcodes,
611        which improves performance. This includes the automatically created ones
612        from 23 above.
613    
614    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
615        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
616        the first matched character to be a colon. This applied both to named and
617        numbered groups.
618    
619    29. The ucpinternal.h header file was missing its idempotency #ifdef.
620    
621    30. I was sent a "project" file called libpcre.a.dev which I understand makes
622        building PCRE on Windows easier, so I have included it in the distribution.
623    
624    31. There is now a check in pcretest against a ridiculously large number being
625        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
626        loop, the loop is abandoned.
627    
628    32. Forward references to subpatterns in conditions such as (?(2)...) where
629        subpattern 2 is defined later cause pcre_compile() to search forwards in
630        the pattern for the relevant set of parentheses. This search went wrong
631        when there were unescaped parentheses in a character class, parentheses
632        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
633    
634    33. "Subroutine" calls and backreferences were previously restricted to
635        referencing subpatterns earlier in the regex. This restriction has now
636        been removed.
637    
638    34. Added a number of extra features that are going to be in Perl 5.10. On the
639        whole, these are just syntactic alternatives for features that PCRE had
640        previously implemented using the Python syntax or my own invention. The
641        other formats are all retained for compatibility.
642    
643        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
644            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
645            also .NET compatible.
646    
647        (b) A recursion or subroutine call to a named group can now be defined as
648            (?&name) as well as (?P>name).
649    
650        (c) A backreference to a named group can now be defined as \k<name> or
651            \k'name' as well as (?P=name). The new forms, as well as being in Perl
652            5.10, are also .NET compatible.
653    
654        (d) A conditional reference to a named group can now use the syntax
655            (?(<name>) or (?('name') as well as (?(name).
656    
657        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
658            groups (named and numbered) that are never evaluated inline, but can be
659            called as "subroutines" from elsewhere. In effect, the DEFINE condition
660            is always false. There may be only one alternative in such a group.
661    
662        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
663            as the simple (?(R). The condition is true only if the most recent
664            recursion is that of the given number or name. It does not search out
665            through the entire recursion stack.
666    
667        (g) The escape \gN or \g{N} has been added, where N is a positive or
668            negative number, specifying an absolute or relative reference.
669    
670    35. Tidied to get rid of some further signed/unsigned compiler warnings and
671        some "unreachable code" warnings.
672    
673    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
674        things, this adds five new scripts.
675    
676    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
677        There were also incompatibilities regarding the handling of \Q..\E inside
678        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
679        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
680    
681    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
682        matches an empty string, and forcibly breaks the loop. There were bugs in
683        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
684        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
685        separate and independent bugs (that affected different cases) have been
686        fixed.
687    
688    39. Refactored the code to abolish the use of different opcodes for small
689        capturing bracket numbers. This is a tidy that I avoided doing when I
690        removed the limit on the number of capturing brackets for 3.5 back in 2001.
691        The new approach is not only tidier, it makes it possible to reduce the
692        memory needed to fix the previous bug (38).
693    
694    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
695        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
696        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
697        mode.
698    
699    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
700        report.
701    
702    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
703        copy construction and assignment in the C++ wrapper.
704    
705    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
706        couple of bugs that could have given wrong results in the "--newline=crlf"
707        case.
708    
709    44. Added a number of casts and did some reorganization of signed/unsigned int
710        variables following suggestions from Dair Grant. Also renamed the variable
711        "this" as "item" because it is a C++ keyword.
712    
713    45. Arranged for dftables to add
714    
715          #include "pcre_internal.h"
716    
717        to pcre_chartables.c because without it, gcc 4.x may remove the array
718        definition from the final binary if PCRE is built into a static library and
719        dead code stripping is activated.
720    
721    46. For an unanchored pattern, if a match attempt fails at the start of a
722        newline sequence, and the newline setting is CRLF or ANY, and the next two
723        characters are CRLF, advance by two characters instead of one.
724    
725    
726    Version 6.7 04-Jul-06
727    ---------------------
728    
729     1. In order to handle tests when input lines are enormously long, pcretest has
730        been re-factored so that it automatically extends its buffers when
731        necessary. The code is crude, but this _is_ just a test program. The
732        default size has been increased from 32K to 50K.
733    
734     2. The code in pcre_study() was using the value of the re argument before
735        testing it for NULL. (Of course, in any sensible call of the function, it
736        won't be NULL.)
737    
738     3. The memmove() emulation function in pcre_internal.h, which is used on
739        systems that lack both memmove() and bcopy() - that is, hardly ever -
740        was missing a "static" storage class specifier.
741    
742     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
743        containing an extended class (one that cannot be represented by a bitmap
744        because it contains high-valued characters or Unicode property items, e.g.
745        [\pZ]). Almost always one would set UTF-8 mode when processing such a
746        pattern, but PCRE should not loop if you do not (it no longer does).
747        [Detail: two cases were found: (a) a repeated subpattern containing an
748        extended class; (b) a recursive reference to a subpattern that followed a
749        previous extended class. It wasn't skipping over the extended class
750        correctly when UTF-8 mode was not set.]
751    
752     5. A negated single-character class was not being recognized as fixed-length
753        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
754        compile error "lookbehind assertion is not fixed length".
755    
756     6. The RunPerlTest auxiliary script was showing an unexpected difference
757        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
758        write a Perl script that can interpret lines of an input file either as
759        byte characters or as UTF-8, which is what "perltest" was being required to
760        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
761        can't do is switch easily at run time between having the "use utf8;" pragma
762        or not. In the end, I fudged it by using the RunPerlTest script to insert
763        "use utf8;" explicitly for the UTF-8 tests.
764    
765     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
766        the end of the subject string, contrary to the documentation and to what
767        Perl does. This was true of both matching functions. Now it matches only at
768        the start of the subject and immediately after *internal* newlines.
769    
770     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
771        a pointer to an int instead of a pointer to an unsigned long int. This
772        caused problems on 64-bit systems.
773    
774     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
775        instance of the 'standard' template library not being so standard".
776    
777    10. There was no check on the number of named subpatterns nor the maximum
778        length of a subpattern name. The product of these values is used to compute
779        the size of the memory block for a compiled pattern. By supplying a very
780        long subpattern name and a large number of named subpatterns, the size
781        computation could be caused to overflow. This is now prevented by limiting
782        the length of names to 32 characters, and the number of named subpatterns
783        to 10,000.
784    
785    11. Subpatterns that are repeated with specific counts have to be replicated in
786        the compiled pattern. The size of memory for this was computed from the
787        length of the subpattern and the repeat count. The latter is limited to
788        65535, but there was no limit on the former, meaning that integer overflow
789        could in principle occur. The compiled length of a repeated subpattern is
790        now limited to 30,000 bytes in order to prevent this.
791    
792    12. Added the optional facility to have named substrings with the same name.
793    
794    13. Added the ability to use a named substring as a condition, using the
795        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
796        are numbers (not recommended). Forward references are permitted.
797    
798    14. Added forward references in named backreferences (if you see what I mean).
799    
800    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
801        pattern could run off the end of the subject. For example, the pattern
802        "(?s)(.{1,5})"8 did this with the subject "ab".
803    
804    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
805        PCRE_CASELESS was set when matching characters that were quantified with ?
806        or *.
807    
808    17. A character class other than a single negated character that had a minimum
809        but no maximum quantifier - for example [ab]{6,} - was not handled
810        correctly by pce_dfa_exec(). It would match only one character.
811    
812    18. A valid (though odd) pattern that looked like a POSIX character
813        class but used an invalid character after [ (for example [[,abc,]]) caused
814        pcre_compile() to give the error "Failed: internal error: code overflow" or
815        in some cases to crash with a glibc free() error. This could even happen if
816        the pattern terminated after [[ but there just happened to be a sequence of
817        letters, a binary zero, and a closing ] in the memory that followed.
818    
819    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
820        over the years. Originally (before any Unicode support), just the bottom 8
821        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
822        output from "man perlunicode" includes this:
823    
824          The regular expression compiler produces polymorphic opcodes.  That
825          is, the pattern adapts to the data and automatically switches to
826          the Unicode character scheme when presented with Unicode data--or
827          instead uses a traditional byte scheme when presented with byte
828          data.
829    
830        Sadly, a wide octal escape does not cause a switch, and in a string with
831        no other multibyte characters, these octal escapes are treated as before.
832        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
833        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
834        Unicode string.
835    
836        I have not perpetrated such confusion in PCRE. Up till now, it took just
837        the bottom 8 bits, as in old Perl. I have now made octal escapes with
838        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
839        translate to the appropriate multibyte character.
840    
841    29. Applied some refactoring to reduce the number of warnings from Microsoft
842        and Borland compilers. This has included removing the fudge introduced
843        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
844        a warning about an unused variable.
845    
846    21. PCRE has not included VT (character 0x0b) in the set of whitespace
847        characters since release 4.0, because Perl (from release 5.004) does not.
848        [Or at least, is documented not to: some releases seem to be in conflict
849        with the documentation.] However, when a pattern was studied with
850        pcre_study() and all its branches started with \s, PCRE still included VT
851        as a possible starting character. Of course, this did no harm; it just
852        caused an unnecessary match attempt.
853    
854    22. Removed a now-redundant internal flag bit that recorded the fact that case
855        dependency changed within the pattern. This was once needed for "required
856        byte" processing, but is no longer used. This recovers a now-scarce options
857        bit. Also moved the least significant internal flag bit to the most-
858        significant bit of the word, which was not previously used (hangover from
859        the days when it was an int rather than a uint) to free up another bit for
860        the future.
861    
862    23. Added support for CRLF line endings as well as CR and LF. As well as the
863        default being selectable at build time, it can now be changed at runtime
864        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
865        specify that it is scanning data with non-default line endings.
866    
867    24. Changed the definition of CXXLINK to make it agree with the definition of
868        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
869    
870    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
871        recursions. This makes a big different to stack usage for some patterns.
872    
873    26. If a subpattern containing a named recursion or subroutine reference such
874        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
875        the space required for the compiled pattern went wrong and gave too small a
876        value. Depending on the environment, this could lead to "Failed: internal
877        error: code overflow at offset 49" or "glibc detected double free or
878        corruption" errors.
879    
880    27. Applied patches from Google (a) to support the new newline modes and (b) to
881        advance over multibyte UTF-8 characters in GlobalReplace.
882    
883    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
884        difference for some implementation of PCRE in some Windows version.
885    
886    29. Added some extra testing facilities to pcretest:
887    
888        \q<number>   in a data line sets the "match limit" value
889        \Q<number>   in a data line sets the "match recursion limt" value
890        -S <number>  sets the stack size, where <number> is in megabytes
891    
892        The -S option isn't available for Windows.
893    
894    
895    Version 6.6 06-Feb-06
896    ---------------------
897    
898     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
899        in pcreposix.h. I have copied the definition from pcre.h.
900    
901     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
902        because pcre.h is no longer a built file.
903    
904     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
905        not normally included in the compiled code.
906    
907    
908    Version 6.5 01-Feb-06
909    ---------------------
910    
911     1. When using the partial match feature with pcre_dfa_exec(), it was not
912        anchoring the second and subsequent partial matches at the new starting
913        point. This could lead to incorrect results. For example, with the pattern
914        /1234/, partially matching against "123" and then "a4" gave a match.
915    
916     2. Changes to pcregrep:
917    
918        (a) All non-match returns from pcre_exec() were being treated as failures
919            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
920            error message is output. Some extra information is given for the
921            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
922            probably the only errors that are likely to be caused by users (by
923            specifying a regex that has nested indefinite repeats, for instance).
924            If there are more than 20 of these errors, pcregrep is abandoned.
925    
926        (b) A binary zero was treated as data while matching, but terminated the
927            output line if it was written out. This has been fixed: binary zeroes
928            are now no different to any other data bytes.
929    
930        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
931            used to set a locale for matching. The --locale=xxxx long option has
932            been added (no short equivalent) to specify a locale explicitly on the
933            pcregrep command, overriding the environment variables.
934    
935        (d) When -B was used with -n, some line numbers in the output were one less
936            than they should have been.
937    
938        (e) Added the -o (--only-matching) option.
939    
940        (f) If -A or -C was used with -c (count only), some lines of context were
941            accidentally printed for the final match.
942    
943        (g) Added the -H (--with-filename) option.
944    
945        (h) The combination of options -rh failed to suppress file names for files
946            that were found from directory arguments.
947    
948        (i) Added the -D (--devices) and -d (--directories) options.
949    
950        (j) Added the -F (--fixed-strings) option.
951    
952        (k) Allow "-" to be used as a file name for -f as well as for a data file.
953    
954        (l) Added the --colo(u)r option.
955    
956        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
957            is not present by default.
958    
959     3. A nasty bug was discovered in the handling of recursive patterns, that is,
960        items such as (?R) or (?1), when the recursion could match a number of
961        alternatives. If it matched one of the alternatives, but subsequently,
962        outside the recursion, there was a failure, the code tried to back up into
963        the recursion. However, because of the way PCRE is implemented, this is not
964        possible, and the result was an incorrect result from the match.
965    
966        In order to prevent this happening, the specification of recursion has
967        been changed so that all such subpatterns are automatically treated as
968        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
969    
970     4. I had overlooked the fact that, in some locales, there are characters for
971        which isalpha() is true but neither isupper() nor islower() are true. In
972        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
973        and ordfeminine) are like this. This affected the treatment of \w and \W
974        when they appeared in character classes, but not when they appeared outside
975        a character class. The bit map for "word" characters is now created
976        separately from the results of isalnum() instead of just taking it from the
977        upper, lower, and digit maps. (Plus the underscore character, of course.)
978    
979     5. The above bug also affected the handling of POSIX character classes such as
980        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
981        permanent tables. Instead, the bit maps for such a class were previously
982        created as the appropriate unions of the upper, lower, and digit bitmaps.
983        Now they are created by subtraction from the [[:word:]] class, which has
984        its own bitmap.
985    
986     6. The [[:blank:]] character class matches horizontal, but not vertical space.
987        It is created by subtracting the vertical space characters (\x09, \x0a,
988        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
989        subtraction was done in the overall bitmap for a character class, meaning
990        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
991        be recognized. This bug has been fixed.
992    
993     7. Patches from the folks at Google:
994    
995          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
996          real life, but is still worth protecting against".
997    
998          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
999          regular expressions".
1000    
1001          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1002          have it.
1003    
1004          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1005          "configure" and the latter not, in order to fix a problem somebody had
1006          with compiling the Arg class on HP-UX.
1007    
1008          (e) Improve the error-handling of the C++ wrapper a little bit.
1009    
1010          (f) New tests for checking recursion limiting.
1011    
1012     8. The pcre_memmove() function, which is used only if the environment does not
1013        have a standard memmove() function (and is therefore rarely compiled),
1014        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1015        returning a result (though PCRE never actually uses the result).
1016    
1017     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1018        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1019        returned instead of calling malloc() with an overflowing number that would
1020        most likely cause subsequent chaos.
1021    
1022    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1023    
1024    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1025        with this option is matched, the nmatch and pmatch options of regexec() are
1026        ignored.
1027    
1028    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1029        provided in case anyone wants to the the POSIX interface with UTF-8
1030        strings.
1031    
1032    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1033        C++ linking (needed for some HP-UX environments).
1034    
1035    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1036        (unused parameter) and in the pcre_printint() function (omitted "default"
1037        switch label when the default is to do nothing).
1038    
1039    15. Added some code to make it possible, when PCRE is compiled as a C++
1040        library, to replace subject pointers for pcre_exec() with a smart pointer
1041        class, thus making it possible to process discontinuous strings.
1042    
1043    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1044        much the same function. They were added by different people who were trying
1045        to make PCRE easy to compile on non-Unix systems. It has been suggested
1046        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1047        for compiling on Windows systems. I have therefore replaced it with
1048        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1049        defaults to "extern" for C or "extern C" for C++, which works fine on
1050        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1051        SCOPE with something explicit in config.h. In addition:
1052    
1053        (a) pcreposix.h still had just "extern" instead of either of these macros;
1054            I have replaced it with PCRE_DATA_SCOPE.
1055    
1056        (b) Functions such as _pcre_xclass(), which are internal to the library,
1057            but external in the C sense, all had PCRE_EXPORT in their definitions.
1058            This is apparently wrong for the Windows case, so I have removed it.
1059            (It makes no difference on Unix-like systems.)
1060    
1061    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1062        of recursive calls to match(). This is different to MATCH_LIMIT because
1063        that limits the total number of calls to match(), not all of which increase
1064        the depth of recursion. Limiting the recursion depth limits the amount of
1065        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1066        when PCRE is compiled, and changed at run time. A patch from Google adds
1067        this functionality to the C++ interface.
1068    
1069    18. Changes to the handling of Unicode character properties:
1070    
1071        (a) Updated the table to Unicode 4.1.0.
1072    
1073        (b) Recognize characters that are not in the table as "Cn" (undefined).
1074    
1075        (c) I revised the way the table is implemented to a much improved format
1076            which includes recognition of ranges. It now supports the ranges that
1077            are defined in UnicodeData.txt, and it also amalgamates other
1078            characters into ranges. This has reduced the number of entries in the
1079            table from around 16,000 to around 3,000, thus reducing its size
1080            considerably. I realized I did not need to use a tree structure after
1081            all - a binary chop search is just as efficient. Having reduced the
1082            number of entries, I extended their size from 6 bytes to 8 bytes to
1083            allow for more data.
1084    
1085        (d) Added support for Unicode script names via properties such as \p{Han}.
1086    
1087    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1088        matching that character.
1089    
1090    20. When matching a repeated Unicode property with a minimum greater than zero,
1091        (for example \pL{2,}), PCRE could look past the end of the subject if it
1092        reached it while seeking the minimum number of characters. This could
1093        happen only if some of the characters were more than one byte long, because
1094        there is a check for at least the minimum number of bytes.
1095    
1096    21. Refactored the implementation of \p and \P so as to be more general, to
1097        allow for more different types of property in future. This has changed the
1098        compiled form incompatibly. Anybody with saved compiled patterns that use
1099        \p or \P will have to recompile them.
1100    
1101    22. Added "Any" and "L&" to the supported property types.
1102    
1103    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1104        but give a compile time error if the value is greater than 0xff.
1105    
1106    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1107        accidentally not being installed or uninstalled.
1108    
1109    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1110        made were to insert the current release number. This seemed silly, because
1111        it made things harder for people building PCRE on systems that don't run
1112        "configure". I have turned pcre.h into a distributed file, no longer built
1113        by "configure", with the version identification directly included. There is
1114        no longer a pcre.h.in file.
1115    
1116        However, this change necessitated a change to the pcre-config script as
1117        well. It is built from pcre-config.in, and one of the substitutions was the
1118        release number. I have updated configure.ac so that ./configure now finds
1119        the release number by grepping pcre.h.
1120    
1121    26. Added the ability to run the tests under valgrind.
1122    
1123    
1124    Version 6.4 05-Sep-05
1125    ---------------------
1126    
1127     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1128        "--" to be printed when multiple files were scanned, even when none of the
1129        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1130        consider it to be a bug, and have restored the previous behaviour.
1131    
1132     2. A couple of code tidies to get rid of compiler warnings.
1133    
1134     3. The pcretest program used to cheat by referring to symbols in the library
1135        whose names begin with _pcre_. These are internal symbols that are not
1136        really supposed to be visible externally, and in some environments it is
1137        possible to suppress them. The cheating is now confined to including
1138        certain files from the library's source, which is a bit cleaner.
1139    
1140     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1141        file's purpose clearer.
1142    
1143     5. Reorganized pcre_ucp_findchar().
1144    
1145    
1146  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
1147  ---------------------  ---------------------
1148    

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