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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    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    
43    Version 7.4 21-Sep-07
44    ---------------------
45    
46    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
47        means that a class such as [\s] counted as "explicit reference to CR or
48        LF". That isn't really right - the whole point of the change was to try to
49        help when there was an actual mention of one of the two characters. So now
50        the change happens only if \r or \n (or a literal CR or LF) character is
51        encountered.
52    
53    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
54        of both had grown to the point where there were only 3 bits left.
55        Fortunately, there was spare space in the data structure, and so I have
56        moved the internal flags into a new 16-bit field to free up more option
57        bits.
58    
59    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
60        but did not set the internal JCHANGED flag - either of these is enough to
61        control the way the "get" function works - but the PCRE_INFO_JCHANGED
62        facility is supposed to tell if (?J) was ever used, so now (?J) at the
63        start sets both bits.
64    
65    4.  Added options (at build time, compile time, exec time) to change \R from
66        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
67    
68    5.  doc/pcresyntax.html was missing from the distribution.
69    
70    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
71        compatibility, even though it is no longer used.
72    
73    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
74        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
75        windows.h file is present (where different names are used). [This was
76        reversed later after testing - see 16 below.]
77    
78    8.  Changed all #include <config.h> to #include "config.h". There were also
79        some further <pcre.h> cases that I changed to "pcre.h".
80    
81    9.  When pcregrep was used with the --colour option, it missed the line ending
82        sequence off the lines that it output.
83    
84    10. It was pointed out to me that arrays of string pointers cause lots of
85        relocations when a shared library is dynamically loaded. A technique of
86        using a single long string with a table of offsets can drastically reduce
87        these. I have refactored PCRE in four places to do this. The result is
88        dramatic:
89    
90          Originally:                          290
91          After changing UCP table:            187
92          After changing error message table:   43
93          After changing table of "verbs"       36
94          After changing table of Posix names   22
95    
96        Thanks to the folks working on Gregex for glib for this insight.
97    
98    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
99        unicode-properties was also set.
100    
101    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
102    
103    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
104        checked only for CRLF.
105    
106    14. Added casts to pcretest.c to avoid compiler warnings.
107    
108    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
109    
110    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
111        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
112        entirely. This removes changes made in 7 above.
113    
114    17. The CMake files have been updated, and there is now more information about
115        building with CMake in the NON-UNIX-USE document.
116    
117    
118    Version 7.3 28-Aug-07
119    ---------------------
120    
121     1. In the rejigging of the build system that eventually resulted in 7.1, the
122        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
123        brackets there is not right, since it causes compilers to look for an
124        installed pcre.h, not the version that is in the source that is being
125        compiled (which of course may be different). I have changed it back to:
126    
127          #include "pcre.h"
128    
129        I have a vague recollection that the change was concerned with compiling in
130        different directories, but in the new build system, that is taken care of
131        by the VPATH setting the Makefile.
132    
133     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
134        when the subject happened to end in the byte 0x85 (e.g. if the last
135        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
136        characters but of course it shouldn't be taken as a newline when it is part
137        of another character. The bug was that, for an unlimited repeat of . in
138        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
139        characters when looking for a newline.
140    
141     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
142    
143     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
144        in debug output.
145    
146     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
147        long printing in the pcrecpp unittest when running under MinGW.
148    
149     6. ESC_K was left out of the EBCDIC table.
150    
151     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
152        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
153        limit also applies to "virtual nesting" when a pattern is recursive, and in
154        this case 1000 isn't so big. I have been able to remove this limit at the
155        expense of backing off one optimization in certain circumstances. Normally,
156        when pcre_exec() would call its internal match() function recursively and
157        immediately return the result unconditionally, it uses a "tail recursion"
158        feature to save stack. However, when a subpattern that can match an empty
159        string has an unlimited repetition quantifier, it no longer makes this
160        optimization. That gives it a stack frame in which to save the data for
161        checking that an empty string has been matched. Previously this was taken
162        from the 1000-entry workspace that had been reserved. So now there is no
163        explicit limit, but more stack is used.
164    
165     8. Applied Daniel's patches to solve problems with the import/export magic
166        syntax that is required for Windows, and which was going wrong for the
167        pcreposix and pcrecpp parts of the library. These were overlooked when this
168        problem was solved for the main library.
169    
170     9. There were some crude static tests to avoid integer overflow when computing
171        the size of patterns that contain repeated groups with explicit upper
172        limits. As the maximum quantifier is 65535, the maximum group length was
173        set at 30,000 so that the product of these two numbers did not overflow a
174        32-bit integer. However, it turns out that people want to use groups that
175        are longer than 30,000 bytes (though not repeat them that many times).
176        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
177        made it possible to implement the integer overflow checks in a much more
178        dynamic way, which I have now done. The artificial limitation on group
179        length has been removed - we now have only the limit on the total length of
180        the compiled pattern, which depends on the LINK_SIZE setting.
181    
182    10. Fixed a bug in the documentation for get/copy named substring when
183        duplicate names are permitted. If none of the named substrings are set, the
184        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
185        empty string.
186    
187    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
188        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
189        because the ] is interpreted as the first data character and the
190        terminating ] is not found. PCRE has been made compatible with Perl in this
191        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
192        cause memory overwriting.
193    
194    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
195        string has been matched (to stop an infinite loop). It was not recognizing
196        a conditional subpattern that could match an empty string if that
197        subpattern was within another subpattern. For example, it looped when
198        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
199        condition was not nested. This bug has been fixed.
200    
201    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
202        past the start of the subject in the presence of bytes with the top bit
203        set, for example "\x8aBCD".
204    
205    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
206        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
207    
208    14. Optimized (?!) to (*FAIL).
209    
210    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
211        This restricts code points to be within the range 0 to 0x10FFFF, excluding
212        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
213        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
214        does: it's just the validity check that is more restrictive.
215    
216    16. Inserted checks for integer overflows during escape sequence (backslash)
217        processing, and also fixed erroneous offset values for syntax errors during
218        backslash processing.
219    
220    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
221        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
222    
223    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
224        caused an overrun.
225    
226    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
227        something other than just ASCII characters) inside a group that had an
228        unlimited repeat caused a loop at compile time (while checking to see
229        whether the group could match an empty string).
230    
231    20. Debugging a pattern containing \p or \P could cause a crash. For example,
232        [\P{Any}] did so. (Error in the code for printing property names.)
233    
234    21. An orphan \E inside a character class could cause a crash.
235    
236    22. A repeated capturing bracket such as (A)? could cause a wild memory
237        reference during compilation.
238    
239    23. There are several functions in pcre_compile() that scan along a compiled
240        expression for various reasons (e.g. to see if it's fixed length for look
241        behind). There were bugs in these functions when a repeated \p or \P was
242        present in the pattern. These operators have additional parameters compared
243        with \d, etc, and these were not being taken into account when moving along
244        the compiled data. Specifically:
245    
246        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
247            length.
248    
249        (b) An item such as \pL+ within a repeated group could cause crashes or
250            loops.
251    
252        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
253            "reference to non-existent subpattern" error.
254    
255        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
256    
257    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
258        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
259    
260    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
261    
262    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
263        character were causing crashes (broken optimization).
264    
265    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
266        \p or \P) caused a compile-time loop.
267    
268    28. More problems have arisen in unanchored patterns when CRLF is a valid line
269        break. For example, the unstudied pattern [\r\n]A does not match the string
270        "\r\nA" because change 7.0/46 below moves the current point on by two
271        characters after failing to match at the start. However, the pattern \nA
272        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
273        the same is true. There doesn't seem any very clean way out of this, but
274        what I have chosen to do makes the common cases work: PCRE now takes note
275        of whether there can be an explicit match for \r or \n anywhere in the
276        pattern, and if so, 7.0/46 no longer applies. As part of this change,
277        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
278        pattern has explicit CR or LF references.
279    
280    29. Added (*CR) etc for changing newline setting at start of pattern.
281    
282    
283    Version 7.2 19-Jun-07
284    ---------------------
285    
286     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
287        which is apparently normally available under Windows.
288    
289     2. Re-jig the pcregrep tests with different newline settings in an attempt
290        to make them independent of the local environment's newline setting.
291    
292     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
293    
294     4. Some of the "internals" tests were previously cut out when the link size
295        was not 2, because the output contained actual offsets. The recent new
296        "Z" feature of pcretest means that these can be cut out, making the tests
297        usable with all link sizes.
298    
299     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
300        stack recursion. This gives a massive performance boost under BSD, but just
301        a small improvement under Linux. However, it saves one field in the frame
302        in all cases.
303    
304     6. Added more features from the forthcoming Perl 5.10:
305    
306        (a) (?-n) (where n is a string of digits) is a relative subroutine or
307            recursion call. It refers to the nth most recently opened parentheses.
308    
309        (b) (?+n) is also a relative subroutine call; it refers to the nth next
310            to be opened parentheses.
311    
312        (c) Conditions that refer to capturing parentheses can be specified
313            relatively, for example, (?(-2)... or (?(+3)...
314    
315        (d) \K resets the start of the current match so that everything before
316            is not part of it.
317    
318        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
319    
320        (f) \g{name} is another synonym - part of Perl 5.10's unification of
321            reference syntax.
322    
323        (g) (?| introduces a group in which the numbering of parentheses in each
324            alternative starts with the same number.
325    
326        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
327    
328     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
329        PCRE_INFO_JCHANGED.
330    
331     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
332        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
333        for detecting groups that can match an empty string.
334    
335     9. A pattern with a very large number of alternatives (more than several
336        hundred) was running out of internal workspace during the pre-compile
337        phase, where pcre_compile() figures out how much memory will be needed. A
338        bit of new cunning has reduced the workspace needed for groups with
339        alternatives. The 1000-alternative test pattern now uses 12 bytes of
340        workspace instead of running out of the 4096 that are available.
341    
342    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
343    
344    11. Applied patch from Google to remove an optimization that didn't quite work.
345        The report of the bug said:
346    
347          pcrecpp::RE("a*").FullMatch("aaa") matches, while
348          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
349          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
350    
351    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
352        it matched the wrong number of bytes.
353    
354    
355    Version 7.1 24-Apr-07
356    ---------------------
357    
358     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
359        that is more "standard", making use of automake and other Autotools. There
360        is some re-arrangement of the files and adjustment of comments consequent
361        on this.
362    
363     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
364        for recursive directory scanning broke on some systems because the files
365        are not scanned in any specific order and on different systems the order
366        was different. A call to "sort" has been inserted into RunGrepTest for the
367        approprate test as a short-term fix. In the longer term there may be an
368        alternative.
369    
370     3. I had an email from Eric Raymond about problems translating some of PCRE's
371        man pages to HTML (despite the fact that I distribute HTML pages, some
372        people do their own conversions for various reasons). The problems
373        concerned the use of low-level troff macros .br and .in. I have therefore
374        removed all such uses from the man pages (some were redundant, some could
375        be replaced by .nf/.fi pairs). The 132html script that I use to generate
376        HTML has been updated to handle .nf/.fi and to complain if it encounters
377        .br or .in.
378    
379     4. Updated comments in configure.ac that get placed in config.h.in and also
380        arranged for config.h to be included in the distribution, with the name
381        config.h.generic, for the benefit of those who have to compile without
382        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
383    
384     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
385        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
386        makevp.bat for the current PCRE, using the additional files
387        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
388    
389     6. A Windows user reported a minor discrepancy with test 2, which turned out
390        to be caused by a trailing space on an input line that had got lost in his
391        copy. The trailing space was an accident, so I've just removed it.
392    
393     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
394        that is needed.
395    
396     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
397        as "const" (a) because they are and (b) because it helps the PHP
398        maintainers who have recently made a script to detect big data structures
399        in the php code that should be moved to the .rodata section. I remembered
400        to update Builducptable as well, so it won't revert if ucptable.h is ever
401        re-created.
402    
403     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
404        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
405        order to be able to cut out the UTF-8 tables in the latter when UTF-8
406        support is not required. This saves 1.5-2K of code, which is important in
407        some applications.
408    
409        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
410        so as not to refer to the tables, even though these functions will never be
411        called when UTF-8 support is disabled. Otherwise there are problems with a
412        shared library.
413    
414    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
415    
416        (a) It was defining its arguments as char * instead of void *.
417    
418        (b) It was assuming that all moves were upwards in memory; this was true
419            a long time ago when I wrote it, but is no longer the case.
420    
421        The emulated memove() is provided for those environments that have neither
422        memmove() nor bcopy(). I didn't think anyone used it these days, but that
423        is clearly not the case, as these two bugs were recently reported.
424    
425    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
426        and Detrail to create the HTML documentation, the .txt form of the man
427        pages, and it removes trailing spaces from listed files. It also creates
428        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
429        case, it wraps all the #defines with #ifndefs. This script should be run
430        before "make dist".
431    
432    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
433        with Unicode property support.
434    
435        (a) For a maximizing quantifier, if the two different cases of the
436            character were of different lengths in their UTF-8 codings (there are
437            some cases like this - I found 11), and the matching function had to
438            back up over a mixture of the two cases, it incorrectly assumed they
439            were both the same length.
440    
441        (b) When PCRE was configured to use the heap rather than the stack for
442            recursion during matching, it was not correctly preserving the data for
443            the other case of a UTF-8 character when checking ahead for a match
444            while processing a minimizing repeat. If the check also involved
445            matching a wide character, but failed, corruption could cause an
446            erroneous result when trying to check for a repeat of the original
447            character.
448    
449    13. Some tidying changes to the testing mechanism:
450    
451        (a) The RunTest script now detects the internal link size and whether there
452            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
453            values substituted by "configure". (The RunGrepTest script already did
454            this for UTF-8.) The configure.ac script no longer substitutes the
455            relevant variables.
456    
457        (b) The debugging options /B and /D in pcretest show the compiled bytecode
458            with length and offset values. This means that the output is different
459            for different internal link sizes. Test 2 is skipped for link sizes
460            other than 2 because of this, bypassing the problem. Unfortunately,
461            there was also a test in test 3 (the locale tests) that used /B and
462            failed for link sizes other than 2. Rather than cut the whole test out,
463            I have added a new /Z option to pcretest that replaces the length and
464            offset values with spaces. This is now used to make test 3 independent
465            of link size. (Test 2 will be tidied up later.)
466    
467    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
468        segmentation fault instead of returning the appropriate error message.
469    
470    15. In multiline mode when the newline sequence was set to "any", the pattern
471        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
472        This doesn't seem right; it now treats the CRLF combination as the line
473        ending, and so does not match in that case. It's only a pattern such as ^$
474        that would hit this one: something like ^ABC$ would have failed after \r
475        and then tried again after \r\n.
476    
477    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
478        in an attempt to make files that differ only in their line terminators
479        compare equal. This works on Linux.
480    
481    17. Under certain error circumstances pcregrep might try to free random memory
482        as it exited. This is now fixed, thanks to valgrind.
483    
484    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
485        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
486        was because its rules for how to advance for /g after matching an empty
487        string at the end of a line did not allow for this case. They now check for
488        it specially.
489    
490    20. pcretest is supposed to handle patterns and data of any length, by
491        extending its buffers when necessary. It was getting this wrong when the
492        buffer for a data line had to be extended.
493    
494    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
495        CRLF as a newline sequence.
496    
497    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
498        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
499        I have nevertheless tidied it up.
500    
501    23. Added some casts to kill warnings from HP-UX ia64 compiler.
502    
503    24. Added a man page for pcre-config.
504    
505    
506    Version 7.0 19-Dec-06
507    ---------------------
508    
509     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
510        moving to gcc 4.1.1.
511    
512     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
513        sys/time.h, which is documented as needed for this function. It doesn't
514        seem to matter on Linux, but it showed up on some releases of OS X.
515    
516     3. It seems that there are systems where bytes whose values are greater than
517        127 match isprint() in the "C" locale. The "C" locale should be the
518        default when a C program starts up. In most systems, only ASCII printing
519        characters match isprint(). This difference caused the output from pcretest
520        to vary, making some of the tests fail. I have changed pcretest so that:
521    
522        (a) When it is outputting text in the compiled version of a pattern, bytes
523            other than 32-126 are always shown as hex escapes.
524    
525        (b) When it is outputting text that is a matched part of a subject string,
526            it does the same, unless a different locale has been set for the match
527            (using the /L modifier). In this case, it uses isprint() to decide.
528    
529     4. Fixed a major bug that caused incorrect computation of the amount of memory
530        required for a compiled pattern when options that changed within the
531        pattern affected the logic of the preliminary scan that determines the
532        length. The relevant options are -x, and -i in UTF-8 mode. The result was
533        that the computed length was too small. The symptoms of this bug were
534        either the PCRE error "internal error: code overflow" from pcre_compile(),
535        or a glibc crash with a message such as "pcretest: free(): invalid next
536        size (fast)". Examples of patterns that provoked this bug (shown in
537        pcretest format) are:
538    
539          /(?-x: )/x
540          /(?x)(?-x: \s*#\s*)/
541          /((?i)[\x{c0}])/8
542          /(?i:[\x{c0}])/8
543    
544        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
545        is now done differently.
546    
547     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
548        wrapper classes; (b) implement a new function in the C++ scanner that is
549        more efficient than the old way of doing things because it avoids levels of
550        recursion in the regex matching; (c) add a paragraph to the documentation
551        for the FullMatch() function.
552    
553     6. The escape sequence \n was being treated as whatever was defined as
554        "newline". Not only was this contrary to the documentation, which states
555        that \n is character 10 (hex 0A), but it also went horribly wrong when
556        "newline" was defined as CRLF. This has been fixed.
557    
558     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
559        was being set to -1 for the "end of line" case (supposedly a value that no
560        character can have). Though this value is never used (the check for end of
561        line is "zero bytes in current character"), it caused compiler complaints.
562        I've changed it to 0xffffffff.
563    
564     8. In pcre_version.c, the version string was being built by a sequence of
565        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
566        string (as it is for production releases) called a macro with an empty
567        argument. The C standard says the result of this is undefined. The gcc
568        compiler treats it as an empty string (which was what was wanted) but it is
569        reported that Visual C gives an error. The source has been hacked around to
570        avoid this problem.
571    
572     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
573        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
574        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
575        of them did).
576    
577    10. Originally, pcretest opened its input and output without "b"; then I was
578        told that "b" was needed in some environments, so it was added for release
579        5.0 to both the input and output. (It makes no difference on Unix-like
580        systems.) Later I was told that it is wrong for the input on Windows. I've
581        now abstracted the modes into two macros, to make it easier to fiddle with
582        them, and removed "b" from the input mode under Windows.
583    
584    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
585    
586    12. Added -help and --help to pcretest as an official way of being reminded
587        of the options.
588    
589    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
590        and pcrecpp.cc because they annoy compilers at high warning levels.
591    
592    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
593    
594    15. Fixed an occurrence of == in configure.ac that should have been = (shell
595        scripts are not C programs :-) and which was not noticed because it works
596        on Linux.
597    
598    16. pcretest is supposed to handle any length of pattern and data line (as one
599        line or as a continued sequence of lines) by extending its input buffer if
600        necessary. This feature was broken for very long pattern lines, leading to
601        a string of junk being passed to pcre_compile() if the pattern was longer
602        than about 50K.
603    
604    17. I have done a major re-factoring of the way pcre_compile() computes the
605        amount of memory needed for a compiled pattern. Previously, there was code
606        that made a preliminary scan of the pattern in order to do this. That was
607        OK when PCRE was new, but as the facilities have expanded, it has become
608        harder and harder to keep it in step with the real compile phase, and there
609        have been a number of bugs (see for example, 4 above). I have now found a
610        cunning way of running the real compile function in a "fake" mode that
611        enables it to compute how much memory it would need, while actually only
612        ever using a few hundred bytes of working memory and without too many
613        tests of the mode. This should make future maintenance and development
614        easier. A side effect of this work is that the limit of 200 on the nesting
615        depth of parentheses has been removed (though this was never a serious
616        limitation, I suspect). However, there is a downside: pcre_compile() now
617        runs more slowly than before (30% or more, depending on the pattern). I
618        hope this isn't a big issue. There is no effect on runtime performance.
619    
620    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
621        newline (only possible for the last line of a file) and it was a
622        pattern that set a locale (followed by /Lsomething), pcretest crashed.
623    
624    19. Added additional timing features to pcretest. (1) The -tm option now times
625        matching only, not compiling. (2) Both -t and -tm can be followed, as a
626        separate command line item, by a number that specifies the number of
627        repeats to use when timing. The default is 50000; this gives better
628        precision, but takes uncomfortably long for very large patterns.
629    
630    20. Extended pcre_study() to be more clever in cases where a branch of a
631        subpattern has no definite first character. For example, (a*|b*)[cd] would
632        previously give no result from pcre_study(). Now it recognizes that the
633        first character must be a, b, c, or d.
634    
635    21. There was an incorrect error "recursive call could loop indefinitely" if
636        a subpattern (or the entire pattern) that was being tested for matching an
637        empty string contained only one non-empty item after a nested subpattern.
638        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
639        incorrectly, because the \d was being skipped in the check.
640    
641    22. The pcretest program now has a new pattern option /B and a command line
642        option -b, which is equivalent to adding /B to every pattern. This causes
643        it to show the compiled bytecode, without the additional information that
644        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
645        is the same as /B/I).
646    
647    23. A new optimization is now able automatically to treat some sequences such
648        as a*b as a*+b. More specifically, if something simple (such as a character
649        or a simple class like \d) has an unlimited quantifier, and is followed by
650        something that cannot possibly match the quantified thing, the quantifier
651        is automatically "possessified".
652    
653    24. A recursive reference to a subpattern whose number was greater than 39
654        went wrong under certain circumstances in UTF-8 mode. This bug could also
655        have affected the operation of pcre_study().
656    
657    25. Realized that a little bit of performance could be had by replacing
658        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
659    
660    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
661    
662    27. Possessive quantifiers such as a++ were previously implemented by turning
663        them into atomic groups such as ($>a+). Now they have their own opcodes,
664        which improves performance. This includes the automatically created ones
665        from 23 above.
666    
667    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
668        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
669        the first matched character to be a colon. This applied both to named and
670        numbered groups.
671    
672    29. The ucpinternal.h header file was missing its idempotency #ifdef.
673    
674    30. I was sent a "project" file called libpcre.a.dev which I understand makes
675        building PCRE on Windows easier, so I have included it in the distribution.
676    
677    31. There is now a check in pcretest against a ridiculously large number being
678        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
679        loop, the loop is abandoned.
680    
681    32. Forward references to subpatterns in conditions such as (?(2)...) where
682        subpattern 2 is defined later cause pcre_compile() to search forwards in
683        the pattern for the relevant set of parentheses. This search went wrong
684        when there were unescaped parentheses in a character class, parentheses
685        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
686    
687    33. "Subroutine" calls and backreferences were previously restricted to
688        referencing subpatterns earlier in the regex. This restriction has now
689        been removed.
690    
691    34. Added a number of extra features that are going to be in Perl 5.10. On the
692        whole, these are just syntactic alternatives for features that PCRE had
693        previously implemented using the Python syntax or my own invention. The
694        other formats are all retained for compatibility.
695    
696        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
697            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
698            also .NET compatible.
699    
700        (b) A recursion or subroutine call to a named group can now be defined as
701            (?&name) as well as (?P>name).
702    
703        (c) A backreference to a named group can now be defined as \k<name> or
704            \k'name' as well as (?P=name). The new forms, as well as being in Perl
705            5.10, are also .NET compatible.
706    
707        (d) A conditional reference to a named group can now use the syntax
708            (?(<name>) or (?('name') as well as (?(name).
709    
710        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
711            groups (named and numbered) that are never evaluated inline, but can be
712            called as "subroutines" from elsewhere. In effect, the DEFINE condition
713            is always false. There may be only one alternative in such a group.
714    
715        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
716            as the simple (?(R). The condition is true only if the most recent
717            recursion is that of the given number or name. It does not search out
718            through the entire recursion stack.
719    
720        (g) The escape \gN or \g{N} has been added, where N is a positive or
721            negative number, specifying an absolute or relative reference.
722    
723    35. Tidied to get rid of some further signed/unsigned compiler warnings and
724        some "unreachable code" warnings.
725    
726    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
727        things, this adds five new scripts.
728    
729    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
730        There were also incompatibilities regarding the handling of \Q..\E inside
731        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
732        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
733    
734    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
735        matches an empty string, and forcibly breaks the loop. There were bugs in
736        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
737        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
738        separate and independent bugs (that affected different cases) have been
739        fixed.
740    
741    39. Refactored the code to abolish the use of different opcodes for small
742        capturing bracket numbers. This is a tidy that I avoided doing when I
743        removed the limit on the number of capturing brackets for 3.5 back in 2001.
744        The new approach is not only tidier, it makes it possible to reduce the
745        memory needed to fix the previous bug (38).
746    
747    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
748        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
749        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
750        mode.
751    
752    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
753        report.
754    
755    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
756        copy construction and assignment in the C++ wrapper.
757    
758    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
759        couple of bugs that could have given wrong results in the "--newline=crlf"
760        case.
761    
762    44. Added a number of casts and did some reorganization of signed/unsigned int
763        variables following suggestions from Dair Grant. Also renamed the variable
764        "this" as "item" because it is a C++ keyword.
765    
766    45. Arranged for dftables to add
767    
768          #include "pcre_internal.h"
769    
770        to pcre_chartables.c because without it, gcc 4.x may remove the array
771        definition from the final binary if PCRE is built into a static library and
772        dead code stripping is activated.
773    
774    46. For an unanchored pattern, if a match attempt fails at the start of a
775        newline sequence, and the newline setting is CRLF or ANY, and the next two
776        characters are CRLF, advance by two characters instead of one.
777    
778    
779    Version 6.7 04-Jul-06
780    ---------------------
781    
782     1. In order to handle tests when input lines are enormously long, pcretest has
783        been re-factored so that it automatically extends its buffers when
784        necessary. The code is crude, but this _is_ just a test program. The
785        default size has been increased from 32K to 50K.
786    
787     2. The code in pcre_study() was using the value of the re argument before
788        testing it for NULL. (Of course, in any sensible call of the function, it
789        won't be NULL.)
790    
791     3. The memmove() emulation function in pcre_internal.h, which is used on
792        systems that lack both memmove() and bcopy() - that is, hardly ever -
793        was missing a "static" storage class specifier.
794    
795     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
796        containing an extended class (one that cannot be represented by a bitmap
797        because it contains high-valued characters or Unicode property items, e.g.
798        [\pZ]). Almost always one would set UTF-8 mode when processing such a
799        pattern, but PCRE should not loop if you do not (it no longer does).
800        [Detail: two cases were found: (a) a repeated subpattern containing an
801        extended class; (b) a recursive reference to a subpattern that followed a
802        previous extended class. It wasn't skipping over the extended class
803        correctly when UTF-8 mode was not set.]
804    
805     5. A negated single-character class was not being recognized as fixed-length
806        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
807        compile error "lookbehind assertion is not fixed length".
808    
809     6. The RunPerlTest auxiliary script was showing an unexpected difference
810        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
811        write a Perl script that can interpret lines of an input file either as
812        byte characters or as UTF-8, which is what "perltest" was being required to
813        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
814        can't do is switch easily at run time between having the "use utf8;" pragma
815        or not. In the end, I fudged it by using the RunPerlTest script to insert
816        "use utf8;" explicitly for the UTF-8 tests.
817    
818     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
819        the end of the subject string, contrary to the documentation and to what
820        Perl does. This was true of both matching functions. Now it matches only at
821        the start of the subject and immediately after *internal* newlines.
822    
823     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
824        a pointer to an int instead of a pointer to an unsigned long int. This
825        caused problems on 64-bit systems.
826    
827     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
828        instance of the 'standard' template library not being so standard".
829    
830    10. There was no check on the number of named subpatterns nor the maximum
831        length of a subpattern name. The product of these values is used to compute
832        the size of the memory block for a compiled pattern. By supplying a very
833        long subpattern name and a large number of named subpatterns, the size
834        computation could be caused to overflow. This is now prevented by limiting
835        the length of names to 32 characters, and the number of named subpatterns
836        to 10,000.
837    
838    11. Subpatterns that are repeated with specific counts have to be replicated in
839        the compiled pattern. The size of memory for this was computed from the
840        length of the subpattern and the repeat count. The latter is limited to
841        65535, but there was no limit on the former, meaning that integer overflow
842        could in principle occur. The compiled length of a repeated subpattern is
843        now limited to 30,000 bytes in order to prevent this.
844    
845    12. Added the optional facility to have named substrings with the same name.
846    
847    13. Added the ability to use a named substring as a condition, using the
848        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
849        are numbers (not recommended). Forward references are permitted.
850    
851    14. Added forward references in named backreferences (if you see what I mean).
852    
853    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
854        pattern could run off the end of the subject. For example, the pattern
855        "(?s)(.{1,5})"8 did this with the subject "ab".
856    
857    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
858        PCRE_CASELESS was set when matching characters that were quantified with ?
859        or *.
860    
861    17. A character class other than a single negated character that had a minimum
862        but no maximum quantifier - for example [ab]{6,} - was not handled
863        correctly by pce_dfa_exec(). It would match only one character.
864    
865    18. A valid (though odd) pattern that looked like a POSIX character
866        class but used an invalid character after [ (for example [[,abc,]]) caused
867        pcre_compile() to give the error "Failed: internal error: code overflow" or
868        in some cases to crash with a glibc free() error. This could even happen if
869        the pattern terminated after [[ but there just happened to be a sequence of
870        letters, a binary zero, and a closing ] in the memory that followed.
871    
872    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
873        over the years. Originally (before any Unicode support), just the bottom 8
874        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
875        output from "man perlunicode" includes this:
876    
877          The regular expression compiler produces polymorphic opcodes.  That
878          is, the pattern adapts to the data and automatically switches to
879          the Unicode character scheme when presented with Unicode data--or
880          instead uses a traditional byte scheme when presented with byte
881          data.
882    
883        Sadly, a wide octal escape does not cause a switch, and in a string with
884        no other multibyte characters, these octal escapes are treated as before.
885        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
886        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
887        Unicode string.
888    
889        I have not perpetrated such confusion in PCRE. Up till now, it took just
890        the bottom 8 bits, as in old Perl. I have now made octal escapes with
891        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
892        translate to the appropriate multibyte character.
893    
894    29. Applied some refactoring to reduce the number of warnings from Microsoft
895        and Borland compilers. This has included removing the fudge introduced
896        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
897        a warning about an unused variable.
898    
899    21. PCRE has not included VT (character 0x0b) in the set of whitespace
900        characters since release 4.0, because Perl (from release 5.004) does not.
901        [Or at least, is documented not to: some releases seem to be in conflict
902        with the documentation.] However, when a pattern was studied with
903        pcre_study() and all its branches started with \s, PCRE still included VT
904        as a possible starting character. Of course, this did no harm; it just
905        caused an unnecessary match attempt.
906    
907    22. Removed a now-redundant internal flag bit that recorded the fact that case
908        dependency changed within the pattern. This was once needed for "required
909        byte" processing, but is no longer used. This recovers a now-scarce options
910        bit. Also moved the least significant internal flag bit to the most-
911        significant bit of the word, which was not previously used (hangover from
912        the days when it was an int rather than a uint) to free up another bit for
913        the future.
914    
915    23. Added support for CRLF line endings as well as CR and LF. As well as the
916        default being selectable at build time, it can now be changed at runtime
917        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
918        specify that it is scanning data with non-default line endings.
919    
920    24. Changed the definition of CXXLINK to make it agree with the definition of
921        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
922    
923    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
924        recursions. This makes a big different to stack usage for some patterns.
925    
926    26. If a subpattern containing a named recursion or subroutine reference such
927        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
928        the space required for the compiled pattern went wrong and gave too small a
929        value. Depending on the environment, this could lead to "Failed: internal
930        error: code overflow at offset 49" or "glibc detected double free or
931        corruption" errors.
932    
933    27. Applied patches from Google (a) to support the new newline modes and (b) to
934        advance over multibyte UTF-8 characters in GlobalReplace.
935    
936    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
937        difference for some implementation of PCRE in some Windows version.
938    
939    29. Added some extra testing facilities to pcretest:
940    
941        \q<number>   in a data line sets the "match limit" value
942        \Q<number>   in a data line sets the "match recursion limt" value
943        -S <number>  sets the stack size, where <number> is in megabytes
944    
945        The -S option isn't available for Windows.
946    
947    
948    Version 6.6 06-Feb-06
949    ---------------------
950    
951     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
952        in pcreposix.h. I have copied the definition from pcre.h.
953    
954     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
955        because pcre.h is no longer a built file.
956    
957     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
958        not normally included in the compiled code.
959    
960    
961    Version 6.5 01-Feb-06
962    ---------------------
963    
964     1. When using the partial match feature with pcre_dfa_exec(), it was not
965        anchoring the second and subsequent partial matches at the new starting
966        point. This could lead to incorrect results. For example, with the pattern
967        /1234/, partially matching against "123" and then "a4" gave a match.
968    
969     2. Changes to pcregrep:
970    
971        (a) All non-match returns from pcre_exec() were being treated as failures
972            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
973            error message is output. Some extra information is given for the
974            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
975            probably the only errors that are likely to be caused by users (by
976            specifying a regex that has nested indefinite repeats, for instance).
977            If there are more than 20 of these errors, pcregrep is abandoned.
978    
979        (b) A binary zero was treated as data while matching, but terminated the
980            output line if it was written out. This has been fixed: binary zeroes
981            are now no different to any other data bytes.
982    
983        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
984            used to set a locale for matching. The --locale=xxxx long option has
985            been added (no short equivalent) to specify a locale explicitly on the
986            pcregrep command, overriding the environment variables.
987    
988        (d) When -B was used with -n, some line numbers in the output were one less
989            than they should have been.
990    
991        (e) Added the -o (--only-matching) option.
992    
993        (f) If -A or -C was used with -c (count only), some lines of context were
994            accidentally printed for the final match.
995    
996        (g) Added the -H (--with-filename) option.
997    
998        (h) The combination of options -rh failed to suppress file names for files
999            that were found from directory arguments.
1000    
1001        (i) Added the -D (--devices) and -d (--directories) options.
1002    
1003        (j) Added the -F (--fixed-strings) option.
1004    
1005        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1006    
1007        (l) Added the --colo(u)r option.
1008    
1009        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1010            is not present by default.
1011    
1012     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1013        items such as (?R) or (?1), when the recursion could match a number of
1014        alternatives. If it matched one of the alternatives, but subsequently,
1015        outside the recursion, there was a failure, the code tried to back up into
1016        the recursion. However, because of the way PCRE is implemented, this is not
1017        possible, and the result was an incorrect result from the match.
1018    
1019        In order to prevent this happening, the specification of recursion has
1020        been changed so that all such subpatterns are automatically treated as
1021        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1022    
1023     4. I had overlooked the fact that, in some locales, there are characters for
1024        which isalpha() is true but neither isupper() nor islower() are true. In
1025        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1026        and ordfeminine) are like this. This affected the treatment of \w and \W
1027        when they appeared in character classes, but not when they appeared outside
1028        a character class. The bit map for "word" characters is now created
1029        separately from the results of isalnum() instead of just taking it from the
1030        upper, lower, and digit maps. (Plus the underscore character, of course.)
1031    
1032     5. The above bug also affected the handling of POSIX character classes such as
1033        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1034        permanent tables. Instead, the bit maps for such a class were previously
1035        created as the appropriate unions of the upper, lower, and digit bitmaps.
1036        Now they are created by subtraction from the [[:word:]] class, which has
1037        its own bitmap.
1038    
1039     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1040        It is created by subtracting the vertical space characters (\x09, \x0a,
1041        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1042        subtraction was done in the overall bitmap for a character class, meaning
1043        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1044        be recognized. This bug has been fixed.
1045    
1046     7. Patches from the folks at Google:
1047    
1048          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1049          real life, but is still worth protecting against".
1050    
1051          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1052          regular expressions".
1053    
1054          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1055          have it.
1056    
1057          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1058          "configure" and the latter not, in order to fix a problem somebody had
1059          with compiling the Arg class on HP-UX.
1060    
1061          (e) Improve the error-handling of the C++ wrapper a little bit.
1062    
1063          (f) New tests for checking recursion limiting.
1064    
1065     8. The pcre_memmove() function, which is used only if the environment does not
1066        have a standard memmove() function (and is therefore rarely compiled),
1067        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1068        returning a result (though PCRE never actually uses the result).
1069    
1070     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1071        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1072        returned instead of calling malloc() with an overflowing number that would
1073        most likely cause subsequent chaos.
1074    
1075    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1076    
1077    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1078        with this option is matched, the nmatch and pmatch options of regexec() are
1079        ignored.
1080    
1081    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1082        provided in case anyone wants to the the POSIX interface with UTF-8
1083        strings.
1084    
1085    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1086        C++ linking (needed for some HP-UX environments).
1087    
1088    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1089        (unused parameter) and in the pcre_printint() function (omitted "default"
1090        switch label when the default is to do nothing).
1091    
1092    15. Added some code to make it possible, when PCRE is compiled as a C++
1093        library, to replace subject pointers for pcre_exec() with a smart pointer
1094        class, thus making it possible to process discontinuous strings.
1095    
1096    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1097        much the same function. They were added by different people who were trying
1098        to make PCRE easy to compile on non-Unix systems. It has been suggested
1099        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1100        for compiling on Windows systems. I have therefore replaced it with
1101        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1102        defaults to "extern" for C or "extern C" for C++, which works fine on
1103        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1104        SCOPE with something explicit in config.h. In addition:
1105    
1106        (a) pcreposix.h still had just "extern" instead of either of these macros;
1107            I have replaced it with PCRE_DATA_SCOPE.
1108    
1109        (b) Functions such as _pcre_xclass(), which are internal to the library,
1110            but external in the C sense, all had PCRE_EXPORT in their definitions.
1111            This is apparently wrong for the Windows case, so I have removed it.
1112            (It makes no difference on Unix-like systems.)
1113    
1114    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1115        of recursive calls to match(). This is different to MATCH_LIMIT because
1116        that limits the total number of calls to match(), not all of which increase
1117        the depth of recursion. Limiting the recursion depth limits the amount of
1118        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1119        when PCRE is compiled, and changed at run time. A patch from Google adds
1120        this functionality to the C++ interface.
1121    
1122    18. Changes to the handling of Unicode character properties:
1123    
1124        (a) Updated the table to Unicode 4.1.0.
1125    
1126        (b) Recognize characters that are not in the table as "Cn" (undefined).
1127    
1128        (c) I revised the way the table is implemented to a much improved format
1129            which includes recognition of ranges. It now supports the ranges that
1130            are defined in UnicodeData.txt, and it also amalgamates other
1131            characters into ranges. This has reduced the number of entries in the
1132            table from around 16,000 to around 3,000, thus reducing its size
1133            considerably. I realized I did not need to use a tree structure after
1134            all - a binary chop search is just as efficient. Having reduced the
1135            number of entries, I extended their size from 6 bytes to 8 bytes to
1136            allow for more data.
1137    
1138        (d) Added support for Unicode script names via properties such as \p{Han}.
1139    
1140    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1141        matching that character.
1142    
1143    20. When matching a repeated Unicode property with a minimum greater than zero,
1144        (for example \pL{2,}), PCRE could look past the end of the subject if it
1145        reached it while seeking the minimum number of characters. This could
1146        happen only if some of the characters were more than one byte long, because
1147        there is a check for at least the minimum number of bytes.
1148    
1149    21. Refactored the implementation of \p and \P so as to be more general, to
1150        allow for more different types of property in future. This has changed the
1151        compiled form incompatibly. Anybody with saved compiled patterns that use
1152        \p or \P will have to recompile them.
1153    
1154    22. Added "Any" and "L&" to the supported property types.
1155    
1156    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1157        but give a compile time error if the value is greater than 0xff.
1158    
1159    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1160        accidentally not being installed or uninstalled.
1161    
1162    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1163        made were to insert the current release number. This seemed silly, because
1164        it made things harder for people building PCRE on systems that don't run
1165        "configure". I have turned pcre.h into a distributed file, no longer built
1166        by "configure", with the version identification directly included. There is
1167        no longer a pcre.h.in file.
1168    
1169        However, this change necessitated a change to the pcre-config script as
1170        well. It is built from pcre-config.in, and one of the substitutions was the
1171        release number. I have updated configure.ac so that ./configure now finds
1172        the release number by grepping pcre.h.
1173    
1174    26. Added the ability to run the tests under valgrind.
1175    
1176    
1177    Version 6.4 05-Sep-05
1178    ---------------------
1179    
1180     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1181        "--" to be printed when multiple files were scanned, even when none of the
1182        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1183        consider it to be a bug, and have restored the previous behaviour.
1184    
1185     2. A couple of code tidies to get rid of compiler warnings.
1186    
1187     3. The pcretest program used to cheat by referring to symbols in the library
1188        whose names begin with _pcre_. These are internal symbols that are not
1189        really supposed to be visible externally, and in some environments it is
1190        possible to suppress them. The cheating is now confined to including
1191        certain files from the library's source, which is a bit cleaner.
1192    
1193     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1194        file's purpose clearer.
1195    
1196     5. Reorganized pcre_ucp_findchar().
1197    
1198    
1199    Version 6.3 15-Aug-05
1200    ---------------------
1201    
1202     1. The file libpcre.pc.in did not have general read permission in the tarball.
1203    
1204     2. There were some problems when building without C++ support:
1205    
1206        (a) If C++ support was not built, "make install" and "make test" still
1207            tried to test it.
1208    
1209        (b) There were problems when the value of CXX was explicitly set. Some
1210            changes have been made to try to fix these, and ...
1211    
1212        (c) --disable-cpp can now be used to explicitly disable C++ support.
1213    
1214        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1215            backslash in a target when C++ was disabled. This confuses some
1216            versions of "make", apparently. Using an intermediate variable solves
1217            this. (Same for CPP_LOBJ.)
1218    
1219     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1220        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1221        necessary on certain architectures.
1222    
1223     4. Added a setting of -export-symbols-regex to the link command to remove
1224        those symbols that are exported in the C sense, but actually are local
1225        within the library, and not documented. Their names all begin with
1226        "_pcre_". This is not a perfect job, because (a) we have to except some
1227        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1228        available (and never for static libraries). I have made a note to try to
1229        find a way round (a) in the future.
1230    
1231    
1232    Version 6.2 01-Aug-05
1233    ---------------------
1234    
1235     1. There was no test for integer overflow of quantifier values. A construction
1236        such as {1111111111111111} would give undefined results. What is worse, if
1237        a minimum quantifier for a parenthesized subpattern overflowed and became
1238        negative, the calculation of the memory size went wrong. This could have
1239        led to memory overwriting.
1240    
1241     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1242    
1243     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1244        operating environments where this matters.
1245    
1246     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1247        PCRE options from within the C++ wrapper.
1248    
1249     5. Named capturing subpatterns were not being correctly counted when a pattern
1250        was compiled. This caused two problems: (a) If there were more than 100
1251        such subpatterns, the calculation of the memory needed for the whole
1252        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1253        back references of the form \12, where the number was greater than 9, were
1254        not recognized as back references, even though there were sufficient
1255        previous subpatterns.
1256    
1257     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1258        versions of gcc, e.g. 2.95.4.
1259    
1260    
1261  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1262  ---------------------  ---------------------
1263    

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