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revision 83 by nigel, Sat Feb 24 21:41:06 2007 UTC revision 267 by ph10, Wed Nov 14 11:48:49 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.5 12-Nov-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    
22    Version 7.4 21-Sep-07
23    ---------------------
24    
25    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
26        means that a class such as [\s] counted as "explicit reference to CR or
27        LF". That isn't really right - the whole point of the change was to try to
28        help when there was an actual mention of one of the two characters. So now
29        the change happens only if \r or \n (or a literal CR or LF) character is
30        encountered.
31    
32    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
33        of both had grown to the point where there were only 3 bits left.
34        Fortunately, there was spare space in the data structure, and so I have
35        moved the internal flags into a new 16-bit field to free up more option
36        bits.
37    
38    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
39        but did not set the internal JCHANGED flag - either of these is enough to
40        control the way the "get" function works - but the PCRE_INFO_JCHANGED
41        facility is supposed to tell if (?J) was ever used, so now (?J) at the
42        start sets both bits.
43    
44    4.  Added options (at build time, compile time, exec time) to change \R from
45        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
46    
47    5.  doc/pcresyntax.html was missing from the distribution.
48    
49    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
50        compatibility, even though it is no longer used.
51    
52    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
53        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
54        windows.h file is present (where different names are used). [This was
55        reversed later after testing - see 16 below.]
56    
57    8.  Changed all #include <config.h> to #include "config.h". There were also
58        some further <pcre.h> cases that I changed to "pcre.h".
59    
60    9.  When pcregrep was used with the --colour option, it missed the line ending
61        sequence off the lines that it output.
62    
63    10. It was pointed out to me that arrays of string pointers cause lots of
64        relocations when a shared library is dynamically loaded. A technique of
65        using a single long string with a table of offsets can drastically reduce
66        these. I have refactored PCRE in four places to do this. The result is
67        dramatic:
68    
69          Originally:                          290
70          After changing UCP table:            187
71          After changing error message table:   43
72          After changing table of "verbs"       36
73          After changing table of Posix names   22
74    
75        Thanks to the folks working on Gregex for glib for this insight.
76    
77    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
78        unicode-properties was also set.
79    
80    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
81    
82    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
83        checked only for CRLF.
84    
85    14. Added casts to pcretest.c to avoid compiler warnings.
86    
87    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
88    
89    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
90        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
91        entirely. This removes changes made in 7 above.
92    
93    17. The CMake files have been updated, and there is now more information about
94        building with CMake in the NON-UNIX-USE document.
95    
96    
97    Version 7.3 28-Aug-07
98    ---------------------
99    
100     1. In the rejigging of the build system that eventually resulted in 7.1, the
101        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
102        brackets there is not right, since it causes compilers to look for an
103        installed pcre.h, not the version that is in the source that is being
104        compiled (which of course may be different). I have changed it back to:
105    
106          #include "pcre.h"
107    
108        I have a vague recollection that the change was concerned with compiling in
109        different directories, but in the new build system, that is taken care of
110        by the VPATH setting the Makefile.
111    
112     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
113        when the subject happened to end in the byte 0x85 (e.g. if the last
114        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
115        characters but of course it shouldn't be taken as a newline when it is part
116        of another character. The bug was that, for an unlimited repeat of . in
117        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
118        characters when looking for a newline.
119    
120     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
121    
122     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
123        in debug output.
124    
125     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
126        long printing in the pcrecpp unittest when running under MinGW.
127    
128     6. ESC_K was left out of the EBCDIC table.
129    
130     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
131        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
132        limit also applies to "virtual nesting" when a pattern is recursive, and in
133        this case 1000 isn't so big. I have been able to remove this limit at the
134        expense of backing off one optimization in certain circumstances. Normally,
135        when pcre_exec() would call its internal match() function recursively and
136        immediately return the result unconditionally, it uses a "tail recursion"
137        feature to save stack. However, when a subpattern that can match an empty
138        string has an unlimited repetition quantifier, it no longer makes this
139        optimization. That gives it a stack frame in which to save the data for
140        checking that an empty string has been matched. Previously this was taken
141        from the 1000-entry workspace that had been reserved. So now there is no
142        explicit limit, but more stack is used.
143    
144     8. Applied Daniel's patches to solve problems with the import/export magic
145        syntax that is required for Windows, and which was going wrong for the
146        pcreposix and pcrecpp parts of the library. These were overlooked when this
147        problem was solved for the main library.
148    
149     9. There were some crude static tests to avoid integer overflow when computing
150        the size of patterns that contain repeated groups with explicit upper
151        limits. As the maximum quantifier is 65535, the maximum group length was
152        set at 30,000 so that the product of these two numbers did not overflow a
153        32-bit integer. However, it turns out that people want to use groups that
154        are longer than 30,000 bytes (though not repeat them that many times).
155        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
156        made it possible to implement the integer overflow checks in a much more
157        dynamic way, which I have now done. The artificial limitation on group
158        length has been removed - we now have only the limit on the total length of
159        the compiled pattern, which depends on the LINK_SIZE setting.
160    
161    10. Fixed a bug in the documentation for get/copy named substring when
162        duplicate names are permitted. If none of the named substrings are set, the
163        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
164        empty string.
165    
166    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
167        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
168        because the ] is interpreted as the first data character and the
169        terminating ] is not found. PCRE has been made compatible with Perl in this
170        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
171        cause memory overwriting.
172    
173    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
174        string has been matched (to stop an infinite loop). It was not recognizing
175        a conditional subpattern that could match an empty string if that
176        subpattern was within another subpattern. For example, it looped when
177        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
178        condition was not nested. This bug has been fixed.
179    
180    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
181        past the start of the subject in the presence of bytes with the top bit
182        set, for example "\x8aBCD".
183    
184    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
185        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
186    
187    14. Optimized (?!) to (*FAIL).
188    
189    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
190        This restricts code points to be within the range 0 to 0x10FFFF, excluding
191        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
192        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
193        does: it's just the validity check that is more restrictive.
194    
195    16. Inserted checks for integer overflows during escape sequence (backslash)
196        processing, and also fixed erroneous offset values for syntax errors during
197        backslash processing.
198    
199    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
200        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
201    
202    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
203        caused an overrun.
204    
205    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
206        something other than just ASCII characters) inside a group that had an
207        unlimited repeat caused a loop at compile time (while checking to see
208        whether the group could match an empty string).
209    
210    20. Debugging a pattern containing \p or \P could cause a crash. For example,
211        [\P{Any}] did so. (Error in the code for printing property names.)
212    
213    21. An orphan \E inside a character class could cause a crash.
214    
215    22. A repeated capturing bracket such as (A)? could cause a wild memory
216        reference during compilation.
217    
218    23. There are several functions in pcre_compile() that scan along a compiled
219        expression for various reasons (e.g. to see if it's fixed length for look
220        behind). There were bugs in these functions when a repeated \p or \P was
221        present in the pattern. These operators have additional parameters compared
222        with \d, etc, and these were not being taken into account when moving along
223        the compiled data. Specifically:
224    
225        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
226            length.
227    
228        (b) An item such as \pL+ within a repeated group could cause crashes or
229            loops.
230    
231        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
232            "reference to non-existent subpattern" error.
233    
234        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
235    
236    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
237        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
238    
239    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
240    
241    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
242        character were causing crashes (broken optimization).
243    
244    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
245        \p or \P) caused a compile-time loop.
246    
247    28. More problems have arisen in unanchored patterns when CRLF is a valid line
248        break. For example, the unstudied pattern [\r\n]A does not match the string
249        "\r\nA" because change 7.0/46 below moves the current point on by two
250        characters after failing to match at the start. However, the pattern \nA
251        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
252        the same is true. There doesn't seem any very clean way out of this, but
253        what I have chosen to do makes the common cases work: PCRE now takes note
254        of whether there can be an explicit match for \r or \n anywhere in the
255        pattern, and if so, 7.0/46 no longer applies. As part of this change,
256        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
257        pattern has explicit CR or LF references.
258    
259    29. Added (*CR) etc for changing newline setting at start of pattern.
260    
261    
262    Version 7.2 19-Jun-07
263    ---------------------
264    
265     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
266        which is apparently normally available under Windows.
267    
268     2. Re-jig the pcregrep tests with different newline settings in an attempt
269        to make them independent of the local environment's newline setting.
270    
271     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
272    
273     4. Some of the "internals" tests were previously cut out when the link size
274        was not 2, because the output contained actual offsets. The recent new
275        "Z" feature of pcretest means that these can be cut out, making the tests
276        usable with all link sizes.
277    
278     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
279        stack recursion. This gives a massive performance boost under BSD, but just
280        a small improvement under Linux. However, it saves one field in the frame
281        in all cases.
282    
283     6. Added more features from the forthcoming Perl 5.10:
284    
285        (a) (?-n) (where n is a string of digits) is a relative subroutine or
286            recursion call. It refers to the nth most recently opened parentheses.
287    
288        (b) (?+n) is also a relative subroutine call; it refers to the nth next
289            to be opened parentheses.
290    
291        (c) Conditions that refer to capturing parentheses can be specified
292            relatively, for example, (?(-2)... or (?(+3)...
293    
294        (d) \K resets the start of the current match so that everything before
295            is not part of it.
296    
297        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
298    
299        (f) \g{name} is another synonym - part of Perl 5.10's unification of
300            reference syntax.
301    
302        (g) (?| introduces a group in which the numbering of parentheses in each
303            alternative starts with the same number.
304    
305        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
306    
307     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
308        PCRE_INFO_JCHANGED.
309    
310     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
311        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
312        for detecting groups that can match an empty string.
313    
314     9. A pattern with a very large number of alternatives (more than several
315        hundred) was running out of internal workspace during the pre-compile
316        phase, where pcre_compile() figures out how much memory will be needed. A
317        bit of new cunning has reduced the workspace needed for groups with
318        alternatives. The 1000-alternative test pattern now uses 12 bytes of
319        workspace instead of running out of the 4096 that are available.
320    
321    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
322    
323    11. Applied patch from Google to remove an optimization that didn't quite work.
324        The report of the bug said:
325    
326          pcrecpp::RE("a*").FullMatch("aaa") matches, while
327          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
328          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
329    
330    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
331        it matched the wrong number of bytes.
332    
333    
334    Version 7.1 24-Apr-07
335    ---------------------
336    
337     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
338        that is more "standard", making use of automake and other Autotools. There
339        is some re-arrangement of the files and adjustment of comments consequent
340        on this.
341    
342     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
343        for recursive directory scanning broke on some systems because the files
344        are not scanned in any specific order and on different systems the order
345        was different. A call to "sort" has been inserted into RunGrepTest for the
346        approprate test as a short-term fix. In the longer term there may be an
347        alternative.
348    
349     3. I had an email from Eric Raymond about problems translating some of PCRE's
350        man pages to HTML (despite the fact that I distribute HTML pages, some
351        people do their own conversions for various reasons). The problems
352        concerned the use of low-level troff macros .br and .in. I have therefore
353        removed all such uses from the man pages (some were redundant, some could
354        be replaced by .nf/.fi pairs). The 132html script that I use to generate
355        HTML has been updated to handle .nf/.fi and to complain if it encounters
356        .br or .in.
357    
358     4. Updated comments in configure.ac that get placed in config.h.in and also
359        arranged for config.h to be included in the distribution, with the name
360        config.h.generic, for the benefit of those who have to compile without
361        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
362    
363     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
364        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
365        makevp.bat for the current PCRE, using the additional files
366        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
367    
368     6. A Windows user reported a minor discrepancy with test 2, which turned out
369        to be caused by a trailing space on an input line that had got lost in his
370        copy. The trailing space was an accident, so I've just removed it.
371    
372     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
373        that is needed.
374    
375     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
376        as "const" (a) because they are and (b) because it helps the PHP
377        maintainers who have recently made a script to detect big data structures
378        in the php code that should be moved to the .rodata section. I remembered
379        to update Builducptable as well, so it won't revert if ucptable.h is ever
380        re-created.
381    
382     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
383        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
384        order to be able to cut out the UTF-8 tables in the latter when UTF-8
385        support is not required. This saves 1.5-2K of code, which is important in
386        some applications.
387    
388        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
389        so as not to refer to the tables, even though these functions will never be
390        called when UTF-8 support is disabled. Otherwise there are problems with a
391        shared library.
392    
393    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
394    
395        (a) It was defining its arguments as char * instead of void *.
396    
397        (b) It was assuming that all moves were upwards in memory; this was true
398            a long time ago when I wrote it, but is no longer the case.
399    
400        The emulated memove() is provided for those environments that have neither
401        memmove() nor bcopy(). I didn't think anyone used it these days, but that
402        is clearly not the case, as these two bugs were recently reported.
403    
404    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
405        and Detrail to create the HTML documentation, the .txt form of the man
406        pages, and it removes trailing spaces from listed files. It also creates
407        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
408        case, it wraps all the #defines with #ifndefs. This script should be run
409        before "make dist".
410    
411    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
412        with Unicode property support.
413    
414        (a) For a maximizing quantifier, if the two different cases of the
415            character were of different lengths in their UTF-8 codings (there are
416            some cases like this - I found 11), and the matching function had to
417            back up over a mixture of the two cases, it incorrectly assumed they
418            were both the same length.
419    
420        (b) When PCRE was configured to use the heap rather than the stack for
421            recursion during matching, it was not correctly preserving the data for
422            the other case of a UTF-8 character when checking ahead for a match
423            while processing a minimizing repeat. If the check also involved
424            matching a wide character, but failed, corruption could cause an
425            erroneous result when trying to check for a repeat of the original
426            character.
427    
428    13. Some tidying changes to the testing mechanism:
429    
430        (a) The RunTest script now detects the internal link size and whether there
431            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
432            values substituted by "configure". (The RunGrepTest script already did
433            this for UTF-8.) The configure.ac script no longer substitutes the
434            relevant variables.
435    
436        (b) The debugging options /B and /D in pcretest show the compiled bytecode
437            with length and offset values. This means that the output is different
438            for different internal link sizes. Test 2 is skipped for link sizes
439            other than 2 because of this, bypassing the problem. Unfortunately,
440            there was also a test in test 3 (the locale tests) that used /B and
441            failed for link sizes other than 2. Rather than cut the whole test out,
442            I have added a new /Z option to pcretest that replaces the length and
443            offset values with spaces. This is now used to make test 3 independent
444            of link size. (Test 2 will be tidied up later.)
445    
446    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
447        segmentation fault instead of returning the appropriate error message.
448    
449    15. In multiline mode when the newline sequence was set to "any", the pattern
450        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
451        This doesn't seem right; it now treats the CRLF combination as the line
452        ending, and so does not match in that case. It's only a pattern such as ^$
453        that would hit this one: something like ^ABC$ would have failed after \r
454        and then tried again after \r\n.
455    
456    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
457        in an attempt to make files that differ only in their line terminators
458        compare equal. This works on Linux.
459    
460    17. Under certain error circumstances pcregrep might try to free random memory
461        as it exited. This is now fixed, thanks to valgrind.
462    
463    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
464        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
465        was because its rules for how to advance for /g after matching an empty
466        string at the end of a line did not allow for this case. They now check for
467        it specially.
468    
469    20. pcretest is supposed to handle patterns and data of any length, by
470        extending its buffers when necessary. It was getting this wrong when the
471        buffer for a data line had to be extended.
472    
473    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
474        CRLF as a newline sequence.
475    
476    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
477        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
478        I have nevertheless tidied it up.
479    
480    23. Added some casts to kill warnings from HP-UX ia64 compiler.
481    
482    24. Added a man page for pcre-config.
483    
484    
485    Version 7.0 19-Dec-06
486    ---------------------
487    
488     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
489        moving to gcc 4.1.1.
490    
491     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
492        sys/time.h, which is documented as needed for this function. It doesn't
493        seem to matter on Linux, but it showed up on some releases of OS X.
494    
495     3. It seems that there are systems where bytes whose values are greater than
496        127 match isprint() in the "C" locale. The "C" locale should be the
497        default when a C program starts up. In most systems, only ASCII printing
498        characters match isprint(). This difference caused the output from pcretest
499        to vary, making some of the tests fail. I have changed pcretest so that:
500    
501        (a) When it is outputting text in the compiled version of a pattern, bytes
502            other than 32-126 are always shown as hex escapes.
503    
504        (b) When it is outputting text that is a matched part of a subject string,
505            it does the same, unless a different locale has been set for the match
506            (using the /L modifier). In this case, it uses isprint() to decide.
507    
508     4. Fixed a major bug that caused incorrect computation of the amount of memory
509        required for a compiled pattern when options that changed within the
510        pattern affected the logic of the preliminary scan that determines the
511        length. The relevant options are -x, and -i in UTF-8 mode. The result was
512        that the computed length was too small. The symptoms of this bug were
513        either the PCRE error "internal error: code overflow" from pcre_compile(),
514        or a glibc crash with a message such as "pcretest: free(): invalid next
515        size (fast)". Examples of patterns that provoked this bug (shown in
516        pcretest format) are:
517    
518          /(?-x: )/x
519          /(?x)(?-x: \s*#\s*)/
520          /((?i)[\x{c0}])/8
521          /(?i:[\x{c0}])/8
522    
523        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
524        is now done differently.
525    
526     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
527        wrapper classes; (b) implement a new function in the C++ scanner that is
528        more efficient than the old way of doing things because it avoids levels of
529        recursion in the regex matching; (c) add a paragraph to the documentation
530        for the FullMatch() function.
531    
532     6. The escape sequence \n was being treated as whatever was defined as
533        "newline". Not only was this contrary to the documentation, which states
534        that \n is character 10 (hex 0A), but it also went horribly wrong when
535        "newline" was defined as CRLF. This has been fixed.
536    
537     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
538        was being set to -1 for the "end of line" case (supposedly a value that no
539        character can have). Though this value is never used (the check for end of
540        line is "zero bytes in current character"), it caused compiler complaints.
541        I've changed it to 0xffffffff.
542    
543     8. In pcre_version.c, the version string was being built by a sequence of
544        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
545        string (as it is for production releases) called a macro with an empty
546        argument. The C standard says the result of this is undefined. The gcc
547        compiler treats it as an empty string (which was what was wanted) but it is
548        reported that Visual C gives an error. The source has been hacked around to
549        avoid this problem.
550    
551     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
552        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
553        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
554        of them did).
555    
556    10. Originally, pcretest opened its input and output without "b"; then I was
557        told that "b" was needed in some environments, so it was added for release
558        5.0 to both the input and output. (It makes no difference on Unix-like
559        systems.) Later I was told that it is wrong for the input on Windows. I've
560        now abstracted the modes into two macros, to make it easier to fiddle with
561        them, and removed "b" from the input mode under Windows.
562    
563    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
564    
565    12. Added -help and --help to pcretest as an official way of being reminded
566        of the options.
567    
568    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
569        and pcrecpp.cc because they annoy compilers at high warning levels.
570    
571    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
572    
573    15. Fixed an occurrence of == in configure.ac that should have been = (shell
574        scripts are not C programs :-) and which was not noticed because it works
575        on Linux.
576    
577    16. pcretest is supposed to handle any length of pattern and data line (as one
578        line or as a continued sequence of lines) by extending its input buffer if
579        necessary. This feature was broken for very long pattern lines, leading to
580        a string of junk being passed to pcre_compile() if the pattern was longer
581        than about 50K.
582    
583    17. I have done a major re-factoring of the way pcre_compile() computes the
584        amount of memory needed for a compiled pattern. Previously, there was code
585        that made a preliminary scan of the pattern in order to do this. That was
586        OK when PCRE was new, but as the facilities have expanded, it has become
587        harder and harder to keep it in step with the real compile phase, and there
588        have been a number of bugs (see for example, 4 above). I have now found a
589        cunning way of running the real compile function in a "fake" mode that
590        enables it to compute how much memory it would need, while actually only
591        ever using a few hundred bytes of working memory and without too many
592        tests of the mode. This should make future maintenance and development
593        easier. A side effect of this work is that the limit of 200 on the nesting
594        depth of parentheses has been removed (though this was never a serious
595        limitation, I suspect). However, there is a downside: pcre_compile() now
596        runs more slowly than before (30% or more, depending on the pattern). I
597        hope this isn't a big issue. There is no effect on runtime performance.
598    
599    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
600        newline (only possible for the last line of a file) and it was a
601        pattern that set a locale (followed by /Lsomething), pcretest crashed.
602    
603    19. Added additional timing features to pcretest. (1) The -tm option now times
604        matching only, not compiling. (2) Both -t and -tm can be followed, as a
605        separate command line item, by a number that specifies the number of
606        repeats to use when timing. The default is 50000; this gives better
607        precision, but takes uncomfortably long for very large patterns.
608    
609    20. Extended pcre_study() to be more clever in cases where a branch of a
610        subpattern has no definite first character. For example, (a*|b*)[cd] would
611        previously give no result from pcre_study(). Now it recognizes that the
612        first character must be a, b, c, or d.
613    
614    21. There was an incorrect error "recursive call could loop indefinitely" if
615        a subpattern (or the entire pattern) that was being tested for matching an
616        empty string contained only one non-empty item after a nested subpattern.
617        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
618        incorrectly, because the \d was being skipped in the check.
619    
620    22. The pcretest program now has a new pattern option /B and a command line
621        option -b, which is equivalent to adding /B to every pattern. This causes
622        it to show the compiled bytecode, without the additional information that
623        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
624        is the same as /B/I).
625    
626    23. A new optimization is now able automatically to treat some sequences such
627        as a*b as a*+b. More specifically, if something simple (such as a character
628        or a simple class like \d) has an unlimited quantifier, and is followed by
629        something that cannot possibly match the quantified thing, the quantifier
630        is automatically "possessified".
631    
632    24. A recursive reference to a subpattern whose number was greater than 39
633        went wrong under certain circumstances in UTF-8 mode. This bug could also
634        have affected the operation of pcre_study().
635    
636    25. Realized that a little bit of performance could be had by replacing
637        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
638    
639    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
640    
641    27. Possessive quantifiers such as a++ were previously implemented by turning
642        them into atomic groups such as ($>a+). Now they have their own opcodes,
643        which improves performance. This includes the automatically created ones
644        from 23 above.
645    
646    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
647        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
648        the first matched character to be a colon. This applied both to named and
649        numbered groups.
650    
651    29. The ucpinternal.h header file was missing its idempotency #ifdef.
652    
653    30. I was sent a "project" file called libpcre.a.dev which I understand makes
654        building PCRE on Windows easier, so I have included it in the distribution.
655    
656    31. There is now a check in pcretest against a ridiculously large number being
657        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
658        loop, the loop is abandoned.
659    
660    32. Forward references to subpatterns in conditions such as (?(2)...) where
661        subpattern 2 is defined later cause pcre_compile() to search forwards in
662        the pattern for the relevant set of parentheses. This search went wrong
663        when there were unescaped parentheses in a character class, parentheses
664        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
665    
666    33. "Subroutine" calls and backreferences were previously restricted to
667        referencing subpatterns earlier in the regex. This restriction has now
668        been removed.
669    
670    34. Added a number of extra features that are going to be in Perl 5.10. On the
671        whole, these are just syntactic alternatives for features that PCRE had
672        previously implemented using the Python syntax or my own invention. The
673        other formats are all retained for compatibility.
674    
675        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
676            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
677            also .NET compatible.
678    
679        (b) A recursion or subroutine call to a named group can now be defined as
680            (?&name) as well as (?P>name).
681    
682        (c) A backreference to a named group can now be defined as \k<name> or
683            \k'name' as well as (?P=name). The new forms, as well as being in Perl
684            5.10, are also .NET compatible.
685    
686        (d) A conditional reference to a named group can now use the syntax
687            (?(<name>) or (?('name') as well as (?(name).
688    
689        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
690            groups (named and numbered) that are never evaluated inline, but can be
691            called as "subroutines" from elsewhere. In effect, the DEFINE condition
692            is always false. There may be only one alternative in such a group.
693    
694        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
695            as the simple (?(R). The condition is true only if the most recent
696            recursion is that of the given number or name. It does not search out
697            through the entire recursion stack.
698    
699        (g) The escape \gN or \g{N} has been added, where N is a positive or
700            negative number, specifying an absolute or relative reference.
701    
702    35. Tidied to get rid of some further signed/unsigned compiler warnings and
703        some "unreachable code" warnings.
704    
705    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
706        things, this adds five new scripts.
707    
708    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
709        There were also incompatibilities regarding the handling of \Q..\E inside
710        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
711        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
712    
713    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
714        matches an empty string, and forcibly breaks the loop. There were bugs in
715        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
716        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
717        separate and independent bugs (that affected different cases) have been
718        fixed.
719    
720    39. Refactored the code to abolish the use of different opcodes for small
721        capturing bracket numbers. This is a tidy that I avoided doing when I
722        removed the limit on the number of capturing brackets for 3.5 back in 2001.
723        The new approach is not only tidier, it makes it possible to reduce the
724        memory needed to fix the previous bug (38).
725    
726    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
727        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
728        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
729        mode.
730    
731    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
732        report.
733    
734    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
735        copy construction and assignment in the C++ wrapper.
736    
737    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
738        couple of bugs that could have given wrong results in the "--newline=crlf"
739        case.
740    
741    44. Added a number of casts and did some reorganization of signed/unsigned int
742        variables following suggestions from Dair Grant. Also renamed the variable
743        "this" as "item" because it is a C++ keyword.
744    
745    45. Arranged for dftables to add
746    
747          #include "pcre_internal.h"
748    
749        to pcre_chartables.c because without it, gcc 4.x may remove the array
750        definition from the final binary if PCRE is built into a static library and
751        dead code stripping is activated.
752    
753    46. For an unanchored pattern, if a match attempt fails at the start of a
754        newline sequence, and the newline setting is CRLF or ANY, and the next two
755        characters are CRLF, advance by two characters instead of one.
756    
757    
758    Version 6.7 04-Jul-06
759    ---------------------
760    
761     1. In order to handle tests when input lines are enormously long, pcretest has
762        been re-factored so that it automatically extends its buffers when
763        necessary. The code is crude, but this _is_ just a test program. The
764        default size has been increased from 32K to 50K.
765    
766     2. The code in pcre_study() was using the value of the re argument before
767        testing it for NULL. (Of course, in any sensible call of the function, it
768        won't be NULL.)
769    
770     3. The memmove() emulation function in pcre_internal.h, which is used on
771        systems that lack both memmove() and bcopy() - that is, hardly ever -
772        was missing a "static" storage class specifier.
773    
774     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
775        containing an extended class (one that cannot be represented by a bitmap
776        because it contains high-valued characters or Unicode property items, e.g.
777        [\pZ]). Almost always one would set UTF-8 mode when processing such a
778        pattern, but PCRE should not loop if you do not (it no longer does).
779        [Detail: two cases were found: (a) a repeated subpattern containing an
780        extended class; (b) a recursive reference to a subpattern that followed a
781        previous extended class. It wasn't skipping over the extended class
782        correctly when UTF-8 mode was not set.]
783    
784     5. A negated single-character class was not being recognized as fixed-length
785        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
786        compile error "lookbehind assertion is not fixed length".
787    
788     6. The RunPerlTest auxiliary script was showing an unexpected difference
789        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
790        write a Perl script that can interpret lines of an input file either as
791        byte characters or as UTF-8, which is what "perltest" was being required to
792        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
793        can't do is switch easily at run time between having the "use utf8;" pragma
794        or not. In the end, I fudged it by using the RunPerlTest script to insert
795        "use utf8;" explicitly for the UTF-8 tests.
796    
797     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
798        the end of the subject string, contrary to the documentation and to what
799        Perl does. This was true of both matching functions. Now it matches only at
800        the start of the subject and immediately after *internal* newlines.
801    
802     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
803        a pointer to an int instead of a pointer to an unsigned long int. This
804        caused problems on 64-bit systems.
805    
806     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
807        instance of the 'standard' template library not being so standard".
808    
809    10. There was no check on the number of named subpatterns nor the maximum
810        length of a subpattern name. The product of these values is used to compute
811        the size of the memory block for a compiled pattern. By supplying a very
812        long subpattern name and a large number of named subpatterns, the size
813        computation could be caused to overflow. This is now prevented by limiting
814        the length of names to 32 characters, and the number of named subpatterns
815        to 10,000.
816    
817    11. Subpatterns that are repeated with specific counts have to be replicated in
818        the compiled pattern. The size of memory for this was computed from the
819        length of the subpattern and the repeat count. The latter is limited to
820        65535, but there was no limit on the former, meaning that integer overflow
821        could in principle occur. The compiled length of a repeated subpattern is
822        now limited to 30,000 bytes in order to prevent this.
823    
824    12. Added the optional facility to have named substrings with the same name.
825    
826    13. Added the ability to use a named substring as a condition, using the
827        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
828        are numbers (not recommended). Forward references are permitted.
829    
830    14. Added forward references in named backreferences (if you see what I mean).
831    
832    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
833        pattern could run off the end of the subject. For example, the pattern
834        "(?s)(.{1,5})"8 did this with the subject "ab".
835    
836    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
837        PCRE_CASELESS was set when matching characters that were quantified with ?
838        or *.
839    
840    17. A character class other than a single negated character that had a minimum
841        but no maximum quantifier - for example [ab]{6,} - was not handled
842        correctly by pce_dfa_exec(). It would match only one character.
843    
844    18. A valid (though odd) pattern that looked like a POSIX character
845        class but used an invalid character after [ (for example [[,abc,]]) caused
846        pcre_compile() to give the error "Failed: internal error: code overflow" or
847        in some cases to crash with a glibc free() error. This could even happen if
848        the pattern terminated after [[ but there just happened to be a sequence of
849        letters, a binary zero, and a closing ] in the memory that followed.
850    
851    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
852        over the years. Originally (before any Unicode support), just the bottom 8
853        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
854        output from "man perlunicode" includes this:
855    
856          The regular expression compiler produces polymorphic opcodes.  That
857          is, the pattern adapts to the data and automatically switches to
858          the Unicode character scheme when presented with Unicode data--or
859          instead uses a traditional byte scheme when presented with byte
860          data.
861    
862        Sadly, a wide octal escape does not cause a switch, and in a string with
863        no other multibyte characters, these octal escapes are treated as before.
864        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
865        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
866        Unicode string.
867    
868        I have not perpetrated such confusion in PCRE. Up till now, it took just
869        the bottom 8 bits, as in old Perl. I have now made octal escapes with
870        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
871        translate to the appropriate multibyte character.
872    
873    29. Applied some refactoring to reduce the number of warnings from Microsoft
874        and Borland compilers. This has included removing the fudge introduced
875        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
876        a warning about an unused variable.
877    
878    21. PCRE has not included VT (character 0x0b) in the set of whitespace
879        characters since release 4.0, because Perl (from release 5.004) does not.
880        [Or at least, is documented not to: some releases seem to be in conflict
881        with the documentation.] However, when a pattern was studied with
882        pcre_study() and all its branches started with \s, PCRE still included VT
883        as a possible starting character. Of course, this did no harm; it just
884        caused an unnecessary match attempt.
885    
886    22. Removed a now-redundant internal flag bit that recorded the fact that case
887        dependency changed within the pattern. This was once needed for "required
888        byte" processing, but is no longer used. This recovers a now-scarce options
889        bit. Also moved the least significant internal flag bit to the most-
890        significant bit of the word, which was not previously used (hangover from
891        the days when it was an int rather than a uint) to free up another bit for
892        the future.
893    
894    23. Added support for CRLF line endings as well as CR and LF. As well as the
895        default being selectable at build time, it can now be changed at runtime
896        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
897        specify that it is scanning data with non-default line endings.
898    
899    24. Changed the definition of CXXLINK to make it agree with the definition of
900        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
901    
902    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
903        recursions. This makes a big different to stack usage for some patterns.
904    
905    26. If a subpattern containing a named recursion or subroutine reference such
906        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
907        the space required for the compiled pattern went wrong and gave too small a
908        value. Depending on the environment, this could lead to "Failed: internal
909        error: code overflow at offset 49" or "glibc detected double free or
910        corruption" errors.
911    
912    27. Applied patches from Google (a) to support the new newline modes and (b) to
913        advance over multibyte UTF-8 characters in GlobalReplace.
914    
915    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
916        difference for some implementation of PCRE in some Windows version.
917    
918    29. Added some extra testing facilities to pcretest:
919    
920        \q<number>   in a data line sets the "match limit" value
921        \Q<number>   in a data line sets the "match recursion limt" value
922        -S <number>  sets the stack size, where <number> is in megabytes
923    
924        The -S option isn't available for Windows.
925    
926    
927    Version 6.6 06-Feb-06
928    ---------------------
929    
930     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
931        in pcreposix.h. I have copied the definition from pcre.h.
932    
933     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
934        because pcre.h is no longer a built file.
935    
936     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
937        not normally included in the compiled code.
938    
939    
940    Version 6.5 01-Feb-06
941    ---------------------
942    
943     1. When using the partial match feature with pcre_dfa_exec(), it was not
944        anchoring the second and subsequent partial matches at the new starting
945        point. This could lead to incorrect results. For example, with the pattern
946        /1234/, partially matching against "123" and then "a4" gave a match.
947    
948     2. Changes to pcregrep:
949    
950        (a) All non-match returns from pcre_exec() were being treated as failures
951            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
952            error message is output. Some extra information is given for the
953            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
954            probably the only errors that are likely to be caused by users (by
955            specifying a regex that has nested indefinite repeats, for instance).
956            If there are more than 20 of these errors, pcregrep is abandoned.
957    
958        (b) A binary zero was treated as data while matching, but terminated the
959            output line if it was written out. This has been fixed: binary zeroes
960            are now no different to any other data bytes.
961    
962        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
963            used to set a locale for matching. The --locale=xxxx long option has
964            been added (no short equivalent) to specify a locale explicitly on the
965            pcregrep command, overriding the environment variables.
966    
967        (d) When -B was used with -n, some line numbers in the output were one less
968            than they should have been.
969    
970        (e) Added the -o (--only-matching) option.
971    
972        (f) If -A or -C was used with -c (count only), some lines of context were
973            accidentally printed for the final match.
974    
975        (g) Added the -H (--with-filename) option.
976    
977        (h) The combination of options -rh failed to suppress file names for files
978            that were found from directory arguments.
979    
980        (i) Added the -D (--devices) and -d (--directories) options.
981    
982        (j) Added the -F (--fixed-strings) option.
983    
984        (k) Allow "-" to be used as a file name for -f as well as for a data file.
985    
986        (l) Added the --colo(u)r option.
987    
988        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
989            is not present by default.
990    
991     3. A nasty bug was discovered in the handling of recursive patterns, that is,
992        items such as (?R) or (?1), when the recursion could match a number of
993        alternatives. If it matched one of the alternatives, but subsequently,
994        outside the recursion, there was a failure, the code tried to back up into
995        the recursion. However, because of the way PCRE is implemented, this is not
996        possible, and the result was an incorrect result from the match.
997    
998        In order to prevent this happening, the specification of recursion has
999        been changed so that all such subpatterns are automatically treated as
1000        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1001    
1002     4. I had overlooked the fact that, in some locales, there are characters for
1003        which isalpha() is true but neither isupper() nor islower() are true. In
1004        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1005        and ordfeminine) are like this. This affected the treatment of \w and \W
1006        when they appeared in character classes, but not when they appeared outside
1007        a character class. The bit map for "word" characters is now created
1008        separately from the results of isalnum() instead of just taking it from the
1009        upper, lower, and digit maps. (Plus the underscore character, of course.)
1010    
1011     5. The above bug also affected the handling of POSIX character classes such as
1012        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1013        permanent tables. Instead, the bit maps for such a class were previously
1014        created as the appropriate unions of the upper, lower, and digit bitmaps.
1015        Now they are created by subtraction from the [[:word:]] class, which has
1016        its own bitmap.
1017    
1018     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1019        It is created by subtracting the vertical space characters (\x09, \x0a,
1020        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1021        subtraction was done in the overall bitmap for a character class, meaning
1022        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1023        be recognized. This bug has been fixed.
1024    
1025     7. Patches from the folks at Google:
1026    
1027          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1028          real life, but is still worth protecting against".
1029    
1030          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1031          regular expressions".
1032    
1033          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1034          have it.
1035    
1036          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1037          "configure" and the latter not, in order to fix a problem somebody had
1038          with compiling the Arg class on HP-UX.
1039    
1040          (e) Improve the error-handling of the C++ wrapper a little bit.
1041    
1042          (f) New tests for checking recursion limiting.
1043    
1044     8. The pcre_memmove() function, which is used only if the environment does not
1045        have a standard memmove() function (and is therefore rarely compiled),
1046        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1047        returning a result (though PCRE never actually uses the result).
1048    
1049     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1050        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1051        returned instead of calling malloc() with an overflowing number that would
1052        most likely cause subsequent chaos.
1053    
1054    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1055    
1056    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1057        with this option is matched, the nmatch and pmatch options of regexec() are
1058        ignored.
1059    
1060    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1061        provided in case anyone wants to the the POSIX interface with UTF-8
1062        strings.
1063    
1064    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1065        C++ linking (needed for some HP-UX environments).
1066    
1067    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1068        (unused parameter) and in the pcre_printint() function (omitted "default"
1069        switch label when the default is to do nothing).
1070    
1071    15. Added some code to make it possible, when PCRE is compiled as a C++
1072        library, to replace subject pointers for pcre_exec() with a smart pointer
1073        class, thus making it possible to process discontinuous strings.
1074    
1075    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1076        much the same function. They were added by different people who were trying
1077        to make PCRE easy to compile on non-Unix systems. It has been suggested
1078        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1079        for compiling on Windows systems. I have therefore replaced it with
1080        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1081        defaults to "extern" for C or "extern C" for C++, which works fine on
1082        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1083        SCOPE with something explicit in config.h. In addition:
1084    
1085        (a) pcreposix.h still had just "extern" instead of either of these macros;
1086            I have replaced it with PCRE_DATA_SCOPE.
1087    
1088        (b) Functions such as _pcre_xclass(), which are internal to the library,
1089            but external in the C sense, all had PCRE_EXPORT in their definitions.
1090            This is apparently wrong for the Windows case, so I have removed it.
1091            (It makes no difference on Unix-like systems.)
1092    
1093    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1094        of recursive calls to match(). This is different to MATCH_LIMIT because
1095        that limits the total number of calls to match(), not all of which increase
1096        the depth of recursion. Limiting the recursion depth limits the amount of
1097        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1098        when PCRE is compiled, and changed at run time. A patch from Google adds
1099        this functionality to the C++ interface.
1100    
1101    18. Changes to the handling of Unicode character properties:
1102    
1103        (a) Updated the table to Unicode 4.1.0.
1104    
1105        (b) Recognize characters that are not in the table as "Cn" (undefined).
1106    
1107        (c) I revised the way the table is implemented to a much improved format
1108            which includes recognition of ranges. It now supports the ranges that
1109            are defined in UnicodeData.txt, and it also amalgamates other
1110            characters into ranges. This has reduced the number of entries in the
1111            table from around 16,000 to around 3,000, thus reducing its size
1112            considerably. I realized I did not need to use a tree structure after
1113            all - a binary chop search is just as efficient. Having reduced the
1114            number of entries, I extended their size from 6 bytes to 8 bytes to
1115            allow for more data.
1116    
1117        (d) Added support for Unicode script names via properties such as \p{Han}.
1118    
1119    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1120        matching that character.
1121    
1122    20. When matching a repeated Unicode property with a minimum greater than zero,
1123        (for example \pL{2,}), PCRE could look past the end of the subject if it
1124        reached it while seeking the minimum number of characters. This could
1125        happen only if some of the characters were more than one byte long, because
1126        there is a check for at least the minimum number of bytes.
1127    
1128    21. Refactored the implementation of \p and \P so as to be more general, to
1129        allow for more different types of property in future. This has changed the
1130        compiled form incompatibly. Anybody with saved compiled patterns that use
1131        \p or \P will have to recompile them.
1132    
1133    22. Added "Any" and "L&" to the supported property types.
1134    
1135    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1136        but give a compile time error if the value is greater than 0xff.
1137    
1138    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1139        accidentally not being installed or uninstalled.
1140    
1141    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1142        made were to insert the current release number. This seemed silly, because
1143        it made things harder for people building PCRE on systems that don't run
1144        "configure". I have turned pcre.h into a distributed file, no longer built
1145        by "configure", with the version identification directly included. There is
1146        no longer a pcre.h.in file.
1147    
1148        However, this change necessitated a change to the pcre-config script as
1149        well. It is built from pcre-config.in, and one of the substitutions was the
1150        release number. I have updated configure.ac so that ./configure now finds
1151        the release number by grepping pcre.h.
1152    
1153    26. Added the ability to run the tests under valgrind.
1154    
1155    
1156    Version 6.4 05-Sep-05
1157    ---------------------
1158    
1159     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1160        "--" to be printed when multiple files were scanned, even when none of the
1161        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1162        consider it to be a bug, and have restored the previous behaviour.
1163    
1164     2. A couple of code tidies to get rid of compiler warnings.
1165    
1166     3. The pcretest program used to cheat by referring to symbols in the library
1167        whose names begin with _pcre_. These are internal symbols that are not
1168        really supposed to be visible externally, and in some environments it is
1169        possible to suppress them. The cheating is now confined to including
1170        certain files from the library's source, which is a bit cleaner.
1171    
1172     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1173        file's purpose clearer.
1174    
1175     5. Reorganized pcre_ucp_findchar().
1176    
1177    
1178  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
1179  ---------------------  ---------------------
1180    

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