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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 12-Nov-07
5    ---------------------
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."
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.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
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.
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).
26    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
27        this is right because (?- can be followed by option settings as well as by
28        digits. I have, however, made the messages clearer.
30    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
31        than the number used in the conditional) now cause a compile-time error.
32        This is actually not compatible with Perl, which accepts such patterns, but
33        treats the conditional as always being FALSE (as PCRE used to), but it
34        seems to me that giving a diagnostic is better.
37    Version 7.4 21-Sep-07
38    ---------------------
40    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
41        means that a class such as [\s] counted as "explicit reference to CR or
42        LF". That isn't really right - the whole point of the change was to try to
43        help when there was an actual mention of one of the two characters. So now
44        the change happens only if \r or \n (or a literal CR or LF) character is
45        encountered.
47    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
48        of both had grown to the point where there were only 3 bits left.
49        Fortunately, there was spare space in the data structure, and so I have
50        moved the internal flags into a new 16-bit field to free up more option
51        bits.
53    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
54        but did not set the internal JCHANGED flag - either of these is enough to
55        control the way the "get" function works - but the PCRE_INFO_JCHANGED
56        facility is supposed to tell if (?J) was ever used, so now (?J) at the
57        start sets both bits.
59    4.  Added options (at build time, compile time, exec time) to change \R from
60        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
62    5.  doc/pcresyntax.html was missing from the distribution.
64    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
65        compatibility, even though it is no longer used.
67    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
68        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
69        windows.h file is present (where different names are used). [This was
70        reversed later after testing - see 16 below.]
72    8.  Changed all #include <config.h> to #include "config.h". There were also
73        some further <pcre.h> cases that I changed to "pcre.h".
75    9.  When pcregrep was used with the --colour option, it missed the line ending
76        sequence off the lines that it output.
78    10. It was pointed out to me that arrays of string pointers cause lots of
79        relocations when a shared library is dynamically loaded. A technique of
80        using a single long string with a table of offsets can drastically reduce
81        these. I have refactored PCRE in four places to do this. The result is
82        dramatic:
84          Originally:                          290
85          After changing UCP table:            187
86          After changing error message table:   43
87          After changing table of "verbs"       36
88          After changing table of Posix names   22
90        Thanks to the folks working on Gregex for glib for this insight.
92    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
93        unicode-properties was also set.
95    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
97    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
98        checked only for CRLF.
100    14. Added casts to pcretest.c to avoid compiler warnings.
102    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
104    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
105        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
106        entirely. This removes changes made in 7 above.
108    17. The CMake files have been updated, and there is now more information about
109        building with CMake in the NON-UNIX-USE document.
112    Version 7.3 28-Aug-07
113    ---------------------
115     1. In the rejigging of the build system that eventually resulted in 7.1, the
116        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
117        brackets there is not right, since it causes compilers to look for an
118        installed pcre.h, not the version that is in the source that is being
119        compiled (which of course may be different). I have changed it back to:
121          #include "pcre.h"
123        I have a vague recollection that the change was concerned with compiling in
124        different directories, but in the new build system, that is taken care of
125        by the VPATH setting the Makefile.
127     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
128        when the subject happened to end in the byte 0x85 (e.g. if the last
129        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
130        characters but of course it shouldn't be taken as a newline when it is part
131        of another character. The bug was that, for an unlimited repeat of . in
132        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
133        characters when looking for a newline.
135     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
137     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
138        in debug output.
140     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
141        long printing in the pcrecpp unittest when running under MinGW.
143     6. ESC_K was left out of the EBCDIC table.
145     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
146        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
147        limit also applies to "virtual nesting" when a pattern is recursive, and in
148        this case 1000 isn't so big. I have been able to remove this limit at the
149        expense of backing off one optimization in certain circumstances. Normally,
150        when pcre_exec() would call its internal match() function recursively and
151        immediately return the result unconditionally, it uses a "tail recursion"
152        feature to save stack. However, when a subpattern that can match an empty
153        string has an unlimited repetition quantifier, it no longer makes this
154        optimization. That gives it a stack frame in which to save the data for
155        checking that an empty string has been matched. Previously this was taken
156        from the 1000-entry workspace that had been reserved. So now there is no
157        explicit limit, but more stack is used.
159     8. Applied Daniel's patches to solve problems with the import/export magic
160        syntax that is required for Windows, and which was going wrong for the
161        pcreposix and pcrecpp parts of the library. These were overlooked when this
162        problem was solved for the main library.
164     9. There were some crude static tests to avoid integer overflow when computing
165        the size of patterns that contain repeated groups with explicit upper
166        limits. As the maximum quantifier is 65535, the maximum group length was
167        set at 30,000 so that the product of these two numbers did not overflow a
168        32-bit integer. However, it turns out that people want to use groups that
169        are longer than 30,000 bytes (though not repeat them that many times).
170        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
171        made it possible to implement the integer overflow checks in a much more
172        dynamic way, which I have now done. The artificial limitation on group
173        length has been removed - we now have only the limit on the total length of
174        the compiled pattern, which depends on the LINK_SIZE setting.
176    10. Fixed a bug in the documentation for get/copy named substring when
177        duplicate names are permitted. If none of the named substrings are set, the
178        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
179        empty string.
181    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
182        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
183        because the ] is interpreted as the first data character and the
184        terminating ] is not found. PCRE has been made compatible with Perl in this
185        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
186        cause memory overwriting.
188    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
189        string has been matched (to stop an infinite loop). It was not recognizing
190        a conditional subpattern that could match an empty string if that
191        subpattern was within another subpattern. For example, it looped when
192        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
193        condition was not nested. This bug has been fixed.
195    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
196        past the start of the subject in the presence of bytes with the top bit
197        set, for example "\x8aBCD".
199    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
200        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
202    14. Optimized (?!) to (*FAIL).
204    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
205        This restricts code points to be within the range 0 to 0x10FFFF, excluding
206        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
207        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
208        does: it's just the validity check that is more restrictive.
210    16. Inserted checks for integer overflows during escape sequence (backslash)
211        processing, and also fixed erroneous offset values for syntax errors during
212        backslash processing.
214    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
215        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
217    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
218        caused an overrun.
220    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
221        something other than just ASCII characters) inside a group that had an
222        unlimited repeat caused a loop at compile time (while checking to see
223        whether the group could match an empty string).
225    20. Debugging a pattern containing \p or \P could cause a crash. For example,
226        [\P{Any}] did so. (Error in the code for printing property names.)
228    21. An orphan \E inside a character class could cause a crash.
230    22. A repeated capturing bracket such as (A)? could cause a wild memory
231        reference during compilation.
233    23. There are several functions in pcre_compile() that scan along a compiled
234        expression for various reasons (e.g. to see if it's fixed length for look
235        behind). There were bugs in these functions when a repeated \p or \P was
236        present in the pattern. These operators have additional parameters compared
237        with \d, etc, and these were not being taken into account when moving along
238        the compiled data. Specifically:
240        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
241            length.
243        (b) An item such as \pL+ within a repeated group could cause crashes or
244            loops.
246        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
247            "reference to non-existent subpattern" error.
249        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
251    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
252        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
254    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
256    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
257        character were causing crashes (broken optimization).
259    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
260        \p or \P) caused a compile-time loop.
262    28. More problems have arisen in unanchored patterns when CRLF is a valid line
263        break. For example, the unstudied pattern [\r\n]A does not match the string
264        "\r\nA" because change 7.0/46 below moves the current point on by two
265        characters after failing to match at the start. However, the pattern \nA
266        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
267        the same is true. There doesn't seem any very clean way out of this, but
268        what I have chosen to do makes the common cases work: PCRE now takes note
269        of whether there can be an explicit match for \r or \n anywhere in the
270        pattern, and if so, 7.0/46 no longer applies. As part of this change,
271        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
272        pattern has explicit CR or LF references.
274    29. Added (*CR) etc for changing newline setting at start of pattern.
277    Version 7.2 19-Jun-07
278    ---------------------
280     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
281        which is apparently normally available under Windows.
283     2. Re-jig the pcregrep tests with different newline settings in an attempt
284        to make them independent of the local environment's newline setting.
286     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
288     4. Some of the "internals" tests were previously cut out when the link size
289        was not 2, because the output contained actual offsets. The recent new
290        "Z" feature of pcretest means that these can be cut out, making the tests
291        usable with all link sizes.
293     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
294        stack recursion. This gives a massive performance boost under BSD, but just
295        a small improvement under Linux. However, it saves one field in the frame
296        in all cases.
298     6. Added more features from the forthcoming Perl 5.10:
300        (a) (?-n) (where n is a string of digits) is a relative subroutine or
301            recursion call. It refers to the nth most recently opened parentheses.
303        (b) (?+n) is also a relative subroutine call; it refers to the nth next
304            to be opened parentheses.
306        (c) Conditions that refer to capturing parentheses can be specified
307            relatively, for example, (?(-2)... or (?(+3)...
309        (d) \K resets the start of the current match so that everything before
310            is not part of it.
312        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
314        (f) \g{name} is another synonym - part of Perl 5.10's unification of
315            reference syntax.
317        (g) (?| introduces a group in which the numbering of parentheses in each
318            alternative starts with the same number.
320        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
322     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
325     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
326        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
327        for detecting groups that can match an empty string.
329     9. A pattern with a very large number of alternatives (more than several
330        hundred) was running out of internal workspace during the pre-compile
331        phase, where pcre_compile() figures out how much memory will be needed. A
332        bit of new cunning has reduced the workspace needed for groups with
333        alternatives. The 1000-alternative test pattern now uses 12 bytes of
334        workspace instead of running out of the 4096 that are available.
336    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
338    11. Applied patch from Google to remove an optimization that didn't quite work.
339        The report of the bug said:
341          pcrecpp::RE("a*").FullMatch("aaa") matches, while
342          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
343          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
345    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
346        it matched the wrong number of bytes.
349    Version 7.1 24-Apr-07
350    ---------------------
352     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
353        that is more "standard", making use of automake and other Autotools. There
354        is some re-arrangement of the files and adjustment of comments consequent
355        on this.
357     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
358        for recursive directory scanning broke on some systems because the files
359        are not scanned in any specific order and on different systems the order
360        was different. A call to "sort" has been inserted into RunGrepTest for the
361        approprate test as a short-term fix. In the longer term there may be an
362        alternative.
364     3. I had an email from Eric Raymond about problems translating some of PCRE's
365        man pages to HTML (despite the fact that I distribute HTML pages, some
366        people do their own conversions for various reasons). The problems
367        concerned the use of low-level troff macros .br and .in. I have therefore
368        removed all such uses from the man pages (some were redundant, some could
369        be replaced by .nf/.fi pairs). The 132html script that I use to generate
370        HTML has been updated to handle .nf/.fi and to complain if it encounters
371        .br or .in.
373     4. Updated comments in configure.ac that get placed in config.h.in and also
374        arranged for config.h to be included in the distribution, with the name
375        config.h.generic, for the benefit of those who have to compile without
376        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
378     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
379        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
380        makevp.bat for the current PCRE, using the additional files
381        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
383     6. A Windows user reported a minor discrepancy with test 2, which turned out
384        to be caused by a trailing space on an input line that had got lost in his
385        copy. The trailing space was an accident, so I've just removed it.
387     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
388        that is needed.
390     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
391        as "const" (a) because they are and (b) because it helps the PHP
392        maintainers who have recently made a script to detect big data structures
393        in the php code that should be moved to the .rodata section. I remembered
394        to update Builducptable as well, so it won't revert if ucptable.h is ever
395        re-created.
397     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
398        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
399        order to be able to cut out the UTF-8 tables in the latter when UTF-8
400        support is not required. This saves 1.5-2K of code, which is important in
401        some applications.
403        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
404        so as not to refer to the tables, even though these functions will never be
405        called when UTF-8 support is disabled. Otherwise there are problems with a
406        shared library.
408    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
410        (a) It was defining its arguments as char * instead of void *.
412        (b) It was assuming that all moves were upwards in memory; this was true
413            a long time ago when I wrote it, but is no longer the case.
415        The emulated memove() is provided for those environments that have neither
416        memmove() nor bcopy(). I didn't think anyone used it these days, but that
417        is clearly not the case, as these two bugs were recently reported.
419    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
420        and Detrail to create the HTML documentation, the .txt form of the man
421        pages, and it removes trailing spaces from listed files. It also creates
422        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
423        case, it wraps all the #defines with #ifndefs. This script should be run
424        before "make dist".
426    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
427        with Unicode property support.
429        (a) For a maximizing quantifier, if the two different cases of the
430            character were of different lengths in their UTF-8 codings (there are
431            some cases like this - I found 11), and the matching function had to
432            back up over a mixture of the two cases, it incorrectly assumed they
433            were both the same length.
435        (b) When PCRE was configured to use the heap rather than the stack for
436            recursion during matching, it was not correctly preserving the data for
437            the other case of a UTF-8 character when checking ahead for a match
438            while processing a minimizing repeat. If the check also involved
439            matching a wide character, but failed, corruption could cause an
440            erroneous result when trying to check for a repeat of the original
441            character.
443    13. Some tidying changes to the testing mechanism:
445        (a) The RunTest script now detects the internal link size and whether there
446            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
447            values substituted by "configure". (The RunGrepTest script already did
448            this for UTF-8.) The configure.ac script no longer substitutes the
449            relevant variables.
451        (b) The debugging options /B and /D in pcretest show the compiled bytecode
452            with length and offset values. This means that the output is different
453            for different internal link sizes. Test 2 is skipped for link sizes
454            other than 2 because of this, bypassing the problem. Unfortunately,
455            there was also a test in test 3 (the locale tests) that used /B and
456            failed for link sizes other than 2. Rather than cut the whole test out,
457            I have added a new /Z option to pcretest that replaces the length and
458            offset values with spaces. This is now used to make test 3 independent
459            of link size. (Test 2 will be tidied up later.)
461    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
462        segmentation fault instead of returning the appropriate error message.
464    15. In multiline mode when the newline sequence was set to "any", the pattern
465        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
466        This doesn't seem right; it now treats the CRLF combination as the line
467        ending, and so does not match in that case. It's only a pattern such as ^$
468        that would hit this one: something like ^ABC$ would have failed after \r
469        and then tried again after \r\n.
471    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
472        in an attempt to make files that differ only in their line terminators
473        compare equal. This works on Linux.
475    17. Under certain error circumstances pcregrep might try to free random memory
476        as it exited. This is now fixed, thanks to valgrind.
478    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
479        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
480        was because its rules for how to advance for /g after matching an empty
481        string at the end of a line did not allow for this case. They now check for
482        it specially.
484    20. pcretest is supposed to handle patterns and data of any length, by
485        extending its buffers when necessary. It was getting this wrong when the
486        buffer for a data line had to be extended.
488    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
489        CRLF as a newline sequence.
491    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
492        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
493        I have nevertheless tidied it up.
495    23. Added some casts to kill warnings from HP-UX ia64 compiler.
497    24. Added a man page for pcre-config.
500    Version 7.0 19-Dec-06
501    ---------------------
503     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
504        moving to gcc 4.1.1.
506     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
507        sys/time.h, which is documented as needed for this function. It doesn't
508        seem to matter on Linux, but it showed up on some releases of OS X.
510     3. It seems that there are systems where bytes whose values are greater than
511        127 match isprint() in the "C" locale. The "C" locale should be the
512        default when a C program starts up. In most systems, only ASCII printing
513        characters match isprint(). This difference caused the output from pcretest
514        to vary, making some of the tests fail. I have changed pcretest so that:
516        (a) When it is outputting text in the compiled version of a pattern, bytes
517            other than 32-126 are always shown as hex escapes.
519        (b) When it is outputting text that is a matched part of a subject string,
520            it does the same, unless a different locale has been set for the match
521            (using the /L modifier). In this case, it uses isprint() to decide.
523     4. Fixed a major bug that caused incorrect computation of the amount of memory
524        required for a compiled pattern when options that changed within the
525        pattern affected the logic of the preliminary scan that determines the
526        length. The relevant options are -x, and -i in UTF-8 mode. The result was
527        that the computed length was too small. The symptoms of this bug were
528        either the PCRE error "internal error: code overflow" from pcre_compile(),
529        or a glibc crash with a message such as "pcretest: free(): invalid next
530        size (fast)". Examples of patterns that provoked this bug (shown in
531        pcretest format) are:
533          /(?-x: )/x
534          /(?x)(?-x: \s*#\s*)/
535          /((?i)[\x{c0}])/8
536          /(?i:[\x{c0}])/8
538        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
539        is now done differently.
541     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
542        wrapper classes; (b) implement a new function in the C++ scanner that is
543        more efficient than the old way of doing things because it avoids levels of
544        recursion in the regex matching; (c) add a paragraph to the documentation
545        for the FullMatch() function.
547     6. The escape sequence \n was being treated as whatever was defined as
548        "newline". Not only was this contrary to the documentation, which states
549        that \n is character 10 (hex 0A), but it also went horribly wrong when
550        "newline" was defined as CRLF. This has been fixed.
552     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
553        was being set to -1 for the "end of line" case (supposedly a value that no
554        character can have). Though this value is never used (the check for end of
555        line is "zero bytes in current character"), it caused compiler complaints.
556        I've changed it to 0xffffffff.
558     8. In pcre_version.c, the version string was being built by a sequence of
559        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
560        string (as it is for production releases) called a macro with an empty
561        argument. The C standard says the result of this is undefined. The gcc
562        compiler treats it as an empty string (which was what was wanted) but it is
563        reported that Visual C gives an error. The source has been hacked around to
564        avoid this problem.
566     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
567        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
568        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
569        of them did).
571    10. Originally, pcretest opened its input and output without "b"; then I was
572        told that "b" was needed in some environments, so it was added for release
573        5.0 to both the input and output. (It makes no difference on Unix-like
574        systems.) Later I was told that it is wrong for the input on Windows. I've
575        now abstracted the modes into two macros, to make it easier to fiddle with
576        them, and removed "b" from the input mode under Windows.
578    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
580    12. Added -help and --help to pcretest as an official way of being reminded
581        of the options.
583    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
584        and pcrecpp.cc because they annoy compilers at high warning levels.
586    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
588    15. Fixed an occurrence of == in configure.ac that should have been = (shell
589        scripts are not C programs :-) and which was not noticed because it works
590        on Linux.
592    16. pcretest is supposed to handle any length of pattern and data line (as one
593        line or as a continued sequence of lines) by extending its input buffer if
594        necessary. This feature was broken for very long pattern lines, leading to
595        a string of junk being passed to pcre_compile() if the pattern was longer
596        than about 50K.
598    17. I have done a major re-factoring of the way pcre_compile() computes the
599        amount of memory needed for a compiled pattern. Previously, there was code
600        that made a preliminary scan of the pattern in order to do this. That was
601        OK when PCRE was new, but as the facilities have expanded, it has become
602        harder and harder to keep it in step with the real compile phase, and there
603        have been a number of bugs (see for example, 4 above). I have now found a
604        cunning way of running the real compile function in a "fake" mode that
605        enables it to compute how much memory it would need, while actually only
606        ever using a few hundred bytes of working memory and without too many
607        tests of the mode. This should make future maintenance and development
608        easier. A side effect of this work is that the limit of 200 on the nesting
609        depth of parentheses has been removed (though this was never a serious
610        limitation, I suspect). However, there is a downside: pcre_compile() now
611        runs more slowly than before (30% or more, depending on the pattern). I
612        hope this isn't a big issue. There is no effect on runtime performance.
614    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
615        newline (only possible for the last line of a file) and it was a
616        pattern that set a locale (followed by /Lsomething), pcretest crashed.
618    19. Added additional timing features to pcretest. (1) The -tm option now times
619        matching only, not compiling. (2) Both -t and -tm can be followed, as a
620        separate command line item, by a number that specifies the number of
621        repeats to use when timing. The default is 50000; this gives better
622        precision, but takes uncomfortably long for very large patterns.
624    20. Extended pcre_study() to be more clever in cases where a branch of a
625        subpattern has no definite first character. For example, (a*|b*)[cd] would
626        previously give no result from pcre_study(). Now it recognizes that the
627        first character must be a, b, c, or d.
629    21. There was an incorrect error "recursive call could loop indefinitely" if
630        a subpattern (or the entire pattern) that was being tested for matching an
631        empty string contained only one non-empty item after a nested subpattern.
632        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
633        incorrectly, because the \d was being skipped in the check.
635    22. The pcretest program now has a new pattern option /B and a command line
636        option -b, which is equivalent to adding /B to every pattern. This causes
637        it to show the compiled bytecode, without the additional information that
638        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
639        is the same as /B/I).
641    23. A new optimization is now able automatically to treat some sequences such
642        as a*b as a*+b. More specifically, if something simple (such as a character
643        or a simple class like \d) has an unlimited quantifier, and is followed by
644        something that cannot possibly match the quantified thing, the quantifier
645        is automatically "possessified".
647    24. A recursive reference to a subpattern whose number was greater than 39
648        went wrong under certain circumstances in UTF-8 mode. This bug could also
649        have affected the operation of pcre_study().
651    25. Realized that a little bit of performance could be had by replacing
652        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
654    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
656    27. Possessive quantifiers such as a++ were previously implemented by turning
657        them into atomic groups such as ($>a+). Now they have their own opcodes,
658        which improves performance. This includes the automatically created ones
659        from 23 above.
661    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
662        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
663        the first matched character to be a colon. This applied both to named and
664        numbered groups.
666    29. The ucpinternal.h header file was missing its idempotency #ifdef.
668    30. I was sent a "project" file called libpcre.a.dev which I understand makes
669        building PCRE on Windows easier, so I have included it in the distribution.
671    31. There is now a check in pcretest against a ridiculously large number being
672        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
673        loop, the loop is abandoned.
675    32. Forward references to subpatterns in conditions such as (?(2)...) where
676        subpattern 2 is defined later cause pcre_compile() to search forwards in
677        the pattern for the relevant set of parentheses. This search went wrong
678        when there were unescaped parentheses in a character class, parentheses
679        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
681    33. "Subroutine" calls and backreferences were previously restricted to
682        referencing subpatterns earlier in the regex. This restriction has now
683        been removed.
685    34. Added a number of extra features that are going to be in Perl 5.10. On the
686        whole, these are just syntactic alternatives for features that PCRE had
687        previously implemented using the Python syntax or my own invention. The
688        other formats are all retained for compatibility.
690        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
691            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
692            also .NET compatible.
694        (b) A recursion or subroutine call to a named group can now be defined as
695            (?&name) as well as (?P>name).
697        (c) A backreference to a named group can now be defined as \k<name> or
698            \k'name' as well as (?P=name). The new forms, as well as being in Perl
699            5.10, are also .NET compatible.
701        (d) A conditional reference to a named group can now use the syntax
702            (?(<name>) or (?('name') as well as (?(name).
704        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
705            groups (named and numbered) that are never evaluated inline, but can be
706            called as "subroutines" from elsewhere. In effect, the DEFINE condition
707            is always false. There may be only one alternative in such a group.
709        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
710            as the simple (?(R). The condition is true only if the most recent
711            recursion is that of the given number or name. It does not search out
712            through the entire recursion stack.
714        (g) The escape \gN or \g{N} has been added, where N is a positive or
715            negative number, specifying an absolute or relative reference.
717    35. Tidied to get rid of some further signed/unsigned compiler warnings and
718        some "unreachable code" warnings.
720    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
721        things, this adds five new scripts.
723    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
724        There were also incompatibilities regarding the handling of \Q..\E inside
725        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
726        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
728    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
729        matches an empty string, and forcibly breaks the loop. There were bugs in
730        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
731        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
732        separate and independent bugs (that affected different cases) have been
733        fixed.
735    39. Refactored the code to abolish the use of different opcodes for small
736        capturing bracket numbers. This is a tidy that I avoided doing when I
737        removed the limit on the number of capturing brackets for 3.5 back in 2001.
738        The new approach is not only tidier, it makes it possible to reduce the
739        memory needed to fix the previous bug (38).
741    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
742        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
743        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
744        mode.
746    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
747        report.
749    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
750        copy construction and assignment in the C++ wrapper.
752    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
753        couple of bugs that could have given wrong results in the "--newline=crlf"
754        case.
756    44. Added a number of casts and did some reorganization of signed/unsigned int
757        variables following suggestions from Dair Grant. Also renamed the variable
758        "this" as "item" because it is a C++ keyword.
760    45. Arranged for dftables to add
762          #include "pcre_internal.h"
764        to pcre_chartables.c because without it, gcc 4.x may remove the array
765        definition from the final binary if PCRE is built into a static library and
766        dead code stripping is activated.
768    46. For an unanchored pattern, if a match attempt fails at the start of a
769        newline sequence, and the newline setting is CRLF or ANY, and the next two
770        characters are CRLF, advance by two characters instead of one.
773    Version 6.7 04-Jul-06
774    ---------------------
776     1. In order to handle tests when input lines are enormously long, pcretest has
777        been re-factored so that it automatically extends its buffers when
778        necessary. The code is crude, but this _is_ just a test program. The
779        default size has been increased from 32K to 50K.
781     2. The code in pcre_study() was using the value of the re argument before
782        testing it for NULL. (Of course, in any sensible call of the function, it
783        won't be NULL.)
785     3. The memmove() emulation function in pcre_internal.h, which is used on
786        systems that lack both memmove() and bcopy() - that is, hardly ever -
787        was missing a "static" storage class specifier.
789     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
790        containing an extended class (one that cannot be represented by a bitmap
791        because it contains high-valued characters or Unicode property items, e.g.
792        [\pZ]). Almost always one would set UTF-8 mode when processing such a
793        pattern, but PCRE should not loop if you do not (it no longer does).
794        [Detail: two cases were found: (a) a repeated subpattern containing an
795        extended class; (b) a recursive reference to a subpattern that followed a
796        previous extended class. It wasn't skipping over the extended class
797        correctly when UTF-8 mode was not set.]
799     5. A negated single-character class was not being recognized as fixed-length
800        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
801        compile error "lookbehind assertion is not fixed length".
803     6. The RunPerlTest auxiliary script was showing an unexpected difference
804        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
805        write a Perl script that can interpret lines of an input file either as
806        byte characters or as UTF-8, which is what "perltest" was being required to
807        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
808        can't do is switch easily at run time between having the "use utf8;" pragma
809        or not. In the end, I fudged it by using the RunPerlTest script to insert
810        "use utf8;" explicitly for the UTF-8 tests.
812     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
813        the end of the subject string, contrary to the documentation and to what
814        Perl does. This was true of both matching functions. Now it matches only at
815        the start of the subject and immediately after *internal* newlines.
817     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
818        a pointer to an int instead of a pointer to an unsigned long int. This
819        caused problems on 64-bit systems.
821     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
822        instance of the 'standard' template library not being so standard".
824    10. There was no check on the number of named subpatterns nor the maximum
825        length of a subpattern name. The product of these values is used to compute
826        the size of the memory block for a compiled pattern. By supplying a very
827        long subpattern name and a large number of named subpatterns, the size
828        computation could be caused to overflow. This is now prevented by limiting
829        the length of names to 32 characters, and the number of named subpatterns
830        to 10,000.
832    11. Subpatterns that are repeated with specific counts have to be replicated in
833        the compiled pattern. The size of memory for this was computed from the
834        length of the subpattern and the repeat count. The latter is limited to
835        65535, but there was no limit on the former, meaning that integer overflow
836        could in principle occur. The compiled length of a repeated subpattern is
837        now limited to 30,000 bytes in order to prevent this.
839    12. Added the optional facility to have named substrings with the same name.
841    13. Added the ability to use a named substring as a condition, using the
842        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
843        are numbers (not recommended). Forward references are permitted.
845    14. Added forward references in named backreferences (if you see what I mean).
847    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
848        pattern could run off the end of the subject. For example, the pattern
849        "(?s)(.{1,5})"8 did this with the subject "ab".
851    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
852        PCRE_CASELESS was set when matching characters that were quantified with ?
853        or *.
855    17. A character class other than a single negated character that had a minimum
856        but no maximum quantifier - for example [ab]{6,} - was not handled
857        correctly by pce_dfa_exec(). It would match only one character.
859    18. A valid (though odd) pattern that looked like a POSIX character
860        class but used an invalid character after [ (for example [[,abc,]]) caused
861        pcre_compile() to give the error "Failed: internal error: code overflow" or
862        in some cases to crash with a glibc free() error. This could even happen if
863        the pattern terminated after [[ but there just happened to be a sequence of
864        letters, a binary zero, and a closing ] in the memory that followed.
866    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
867        over the years. Originally (before any Unicode support), just the bottom 8
868        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
869        output from "man perlunicode" includes this:
871          The regular expression compiler produces polymorphic opcodes.  That
872          is, the pattern adapts to the data and automatically switches to
873          the Unicode character scheme when presented with Unicode data--or
874          instead uses a traditional byte scheme when presented with byte
875          data.
877        Sadly, a wide octal escape does not cause a switch, and in a string with
878        no other multibyte characters, these octal escapes are treated as before.
879        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
880        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
881        Unicode string.
883        I have not perpetrated such confusion in PCRE. Up till now, it took just
884        the bottom 8 bits, as in old Perl. I have now made octal escapes with
885        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
886        translate to the appropriate multibyte character.
888    29. Applied some refactoring to reduce the number of warnings from Microsoft
889        and Borland compilers. This has included removing the fudge introduced
890        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
891        a warning about an unused variable.
893    21. PCRE has not included VT (character 0x0b) in the set of whitespace
894        characters since release 4.0, because Perl (from release 5.004) does not.
895        [Or at least, is documented not to: some releases seem to be in conflict
896        with the documentation.] However, when a pattern was studied with
897        pcre_study() and all its branches started with \s, PCRE still included VT
898        as a possible starting character. Of course, this did no harm; it just
899        caused an unnecessary match attempt.
901    22. Removed a now-redundant internal flag bit that recorded the fact that case
902        dependency changed within the pattern. This was once needed for "required
903        byte" processing, but is no longer used. This recovers a now-scarce options
904        bit. Also moved the least significant internal flag bit to the most-
905        significant bit of the word, which was not previously used (hangover from
906        the days when it was an int rather than a uint) to free up another bit for
907        the future.
909    23. Added support for CRLF line endings as well as CR and LF. As well as the
910        default being selectable at build time, it can now be changed at runtime
911        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
912        specify that it is scanning data with non-default line endings.
914    24. Changed the definition of CXXLINK to make it agree with the definition of
915        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
917    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
918        recursions. This makes a big different to stack usage for some patterns.
920    26. If a subpattern containing a named recursion or subroutine reference such
921        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
922        the space required for the compiled pattern went wrong and gave too small a
923        value. Depending on the environment, this could lead to "Failed: internal
924        error: code overflow at offset 49" or "glibc detected double free or
925        corruption" errors.
927    27. Applied patches from Google (a) to support the new newline modes and (b) to
928        advance over multibyte UTF-8 characters in GlobalReplace.
930    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
931        difference for some implementation of PCRE in some Windows version.
933    29. Added some extra testing facilities to pcretest:
935        \q<number>   in a data line sets the "match limit" value
936        \Q<number>   in a data line sets the "match recursion limt" value
937        -S <number>  sets the stack size, where <number> is in megabytes
939        The -S option isn't available for Windows.
942    Version 6.6 06-Feb-06
943    ---------------------
945     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
946        in pcreposix.h. I have copied the definition from pcre.h.
948     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
949        because pcre.h is no longer a built file.
951     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
952        not normally included in the compiled code.
955    Version 6.5 01-Feb-06
956    ---------------------
958     1. When using the partial match feature with pcre_dfa_exec(), it was not
959        anchoring the second and subsequent partial matches at the new starting
960        point. This could lead to incorrect results. For example, with the pattern
961        /1234/, partially matching against "123" and then "a4" gave a match.
963     2. Changes to pcregrep:
965        (a) All non-match returns from pcre_exec() were being treated as failures
966            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
967            error message is output. Some extra information is given for the
968            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
969            probably the only errors that are likely to be caused by users (by
970            specifying a regex that has nested indefinite repeats, for instance).
971            If there are more than 20 of these errors, pcregrep is abandoned.
973        (b) A binary zero was treated as data while matching, but terminated the
974            output line if it was written out. This has been fixed: binary zeroes
975            are now no different to any other data bytes.
977        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
978            used to set a locale for matching. The --locale=xxxx long option has
979            been added (no short equivalent) to specify a locale explicitly on the
980            pcregrep command, overriding the environment variables.
982        (d) When -B was used with -n, some line numbers in the output were one less
983            than they should have been.
985        (e) Added the -o (--only-matching) option.
987        (f) If -A or -C was used with -c (count only), some lines of context were
988            accidentally printed for the final match.
990        (g) Added the -H (--with-filename) option.
992        (h) The combination of options -rh failed to suppress file names for files
993            that were found from directory arguments.
995        (i) Added the -D (--devices) and -d (--directories) options.
997        (j) Added the -F (--fixed-strings) option.
999        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1001        (l) Added the --colo(u)r option.
1003        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1004            is not present by default.
1006     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1007        items such as (?R) or (?1), when the recursion could match a number of
1008        alternatives. If it matched one of the alternatives, but subsequently,
1009        outside the recursion, there was a failure, the code tried to back up into
1010        the recursion. However, because of the way PCRE is implemented, this is not
1011        possible, and the result was an incorrect result from the match.
1013        In order to prevent this happening, the specification of recursion has
1014        been changed so that all such subpatterns are automatically treated as
1015        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1017     4. I had overlooked the fact that, in some locales, there are characters for
1018        which isalpha() is true but neither isupper() nor islower() are true. In
1019        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1020        and ordfeminine) are like this. This affected the treatment of \w and \W
1021        when they appeared in character classes, but not when they appeared outside
1022        a character class. The bit map for "word" characters is now created
1023        separately from the results of isalnum() instead of just taking it from the
1024        upper, lower, and digit maps. (Plus the underscore character, of course.)
1026     5. The above bug also affected the handling of POSIX character classes such as
1027        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1028        permanent tables. Instead, the bit maps for such a class were previously
1029        created as the appropriate unions of the upper, lower, and digit bitmaps.
1030        Now they are created by subtraction from the [[:word:]] class, which has
1031        its own bitmap.
1033     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1034        It is created by subtracting the vertical space characters (\x09, \x0a,
1035        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1036        subtraction was done in the overall bitmap for a character class, meaning
1037        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1038        be recognized. This bug has been fixed.
1040     7. Patches from the folks at Google:
1042          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1043          real life, but is still worth protecting against".
1045          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1046          regular expressions".
1048          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1049          have it.
1051          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1052          "configure" and the latter not, in order to fix a problem somebody had
1053          with compiling the Arg class on HP-UX.
1055          (e) Improve the error-handling of the C++ wrapper a little bit.
1057          (f) New tests for checking recursion limiting.
1059     8. The pcre_memmove() function, which is used only if the environment does not
1060        have a standard memmove() function (and is therefore rarely compiled),
1061        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1062        returning a result (though PCRE never actually uses the result).
1064     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1065        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1066        returned instead of calling malloc() with an overflowing number that would
1067        most likely cause subsequent chaos.
1069    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1071    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1072        with this option is matched, the nmatch and pmatch options of regexec() are
1073        ignored.
1075    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1076        provided in case anyone wants to the the POSIX interface with UTF-8
1077        strings.
1079    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1080        C++ linking (needed for some HP-UX environments).
1082    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1083        (unused parameter) and in the pcre_printint() function (omitted "default"
1084        switch label when the default is to do nothing).
1086    15. Added some code to make it possible, when PCRE is compiled as a C++
1087        library, to replace subject pointers for pcre_exec() with a smart pointer
1088        class, thus making it possible to process discontinuous strings.
1090    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1091        much the same function. They were added by different people who were trying
1092        to make PCRE easy to compile on non-Unix systems. It has been suggested
1093        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1094        for compiling on Windows systems. I have therefore replaced it with
1095        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1096        defaults to "extern" for C or "extern C" for C++, which works fine on
1097        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1098        SCOPE with something explicit in config.h. In addition:
1100        (a) pcreposix.h still had just "extern" instead of either of these macros;
1101            I have replaced it with PCRE_DATA_SCOPE.
1103        (b) Functions such as _pcre_xclass(), which are internal to the library,
1104            but external in the C sense, all had PCRE_EXPORT in their definitions.
1105            This is apparently wrong for the Windows case, so I have removed it.
1106            (It makes no difference on Unix-like systems.)
1108    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1109        of recursive calls to match(). This is different to MATCH_LIMIT because
1110        that limits the total number of calls to match(), not all of which increase
1111        the depth of recursion. Limiting the recursion depth limits the amount of
1112        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1113        when PCRE is compiled, and changed at run time. A patch from Google adds
1114        this functionality to the C++ interface.
1116    18. Changes to the handling of Unicode character properties:
1118        (a) Updated the table to Unicode 4.1.0.
1120        (b) Recognize characters that are not in the table as "Cn" (undefined).
1122        (c) I revised the way the table is implemented to a much improved format
1123            which includes recognition of ranges. It now supports the ranges that
1124            are defined in UnicodeData.txt, and it also amalgamates other
1125            characters into ranges. This has reduced the number of entries in the
1126            table from around 16,000 to around 3,000, thus reducing its size
1127            considerably. I realized I did not need to use a tree structure after
1128            all - a binary chop search is just as efficient. Having reduced the
1129            number of entries, I extended their size from 6 bytes to 8 bytes to
1130            allow for more data.
1132        (d) Added support for Unicode script names via properties such as \p{Han}.
1134    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1135        matching that character.
1137    20. When matching a repeated Unicode property with a minimum greater than zero,
1138        (for example \pL{2,}), PCRE could look past the end of the subject if it
1139        reached it while seeking the minimum number of characters. This could
1140        happen only if some of the characters were more than one byte long, because
1141        there is a check for at least the minimum number of bytes.
1143    21. Refactored the implementation of \p and \P so as to be more general, to
1144        allow for more different types of property in future. This has changed the
1145        compiled form incompatibly. Anybody with saved compiled patterns that use
1146        \p or \P will have to recompile them.
1148    22. Added "Any" and "L&" to the supported property types.
1150    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1151        but give a compile time error if the value is greater than 0xff.
1153    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1154        accidentally not being installed or uninstalled.
1156    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1157        made were to insert the current release number. This seemed silly, because
1158        it made things harder for people building PCRE on systems that don't run
1159        "configure". I have turned pcre.h into a distributed file, no longer built
1160        by "configure", with the version identification directly included. There is
1161        no longer a pcre.h.in file.
1163        However, this change necessitated a change to the pcre-config script as
1164        well. It is built from pcre-config.in, and one of the substitutions was the
1165        release number. I have updated configure.ac so that ./configure now finds
1166        the release number by grepping pcre.h.
1168    26. Added the ability to run the tests under valgrind.
1171    Version 6.4 05-Sep-05
1172    ---------------------
1174     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1175        "--" to be printed when multiple files were scanned, even when none of the
1176        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1177        consider it to be a bug, and have restored the previous behaviour.
1179     2. A couple of code tidies to get rid of compiler warnings.
1181     3. The pcretest program used to cheat by referring to symbols in the library
1182        whose names begin with _pcre_. These are internal symbols that are not
1183        really supposed to be visible externally, and in some environments it is
1184        possible to suppress them. The cheating is now confined to including
1185        certain files from the library's source, which is a bit cleaner.
1187     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1188        file's purpose clearer.
1190     5. Reorganized pcre_ucp_findchar().
1193    Version 6.3 15-Aug-05
1194    ---------------------
1196     1. The file libpcre.pc.in did not have general read permission in the tarball.
1198     2. There were some problems when building without C++ support:
1200        (a) If C++ support was not built, "make install" and "make test" still
1201            tried to test it.
1203        (b) There were problems when the value of CXX was explicitly set. Some
1204            changes have been made to try to fix these, and ...
1206        (c) --disable-cpp can now be used to explicitly disable C++ support.
1208        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1209            backslash in a target when C++ was disabled. This confuses some
1210            versions of "make", apparently. Using an intermediate variable solves
1211            this. (Same for CPP_LOBJ.)
1213     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1214        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1215        necessary on certain architectures.
1217     4. Added a setting of -export-symbols-regex to the link command to remove
1218        those symbols that are exported in the C sense, but actually are local
1219        within the library, and not documented. Their names all begin with
1220        "_pcre_". This is not a perfect job, because (a) we have to except some
1221        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1222        available (and never for static libraries). I have made a note to try to
1223        find a way round (a) in the future.
1226    Version 6.2 01-Aug-05
1227    ---------------------
1229     1. There was no test for integer overflow of quantifier values. A construction
1230        such as {1111111111111111} would give undefined results. What is worse, if
1231        a minimum quantifier for a parenthesized subpattern overflowed and became
1232        negative, the calculation of the memory size went wrong. This could have
1233        led to memory overwriting.
1235     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1237     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1238        operating environments where this matters.
1240     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1241        PCRE options from within the C++ wrapper.
1243     5. Named capturing subpatterns were not being correctly counted when a pattern
1244        was compiled. This caused two problems: (a) If there were more than 100
1245        such subpatterns, the calculation of the memory needed for the whole
1246        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1247        back references of the form \12, where the number was greater than 9, were
1248        not recognized as back references, even though there were sufficient
1249        previous subpatterns.
1251     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1252        versions of gcc, e.g. 2.95.4.
1255    Version 6.1 21-Jun-05
1256    ---------------------
1258     1. There was one reference to the variable "posix" in pcretest.c that was not
1259        surrounded by "#if !defined NOPOSIX".
1261     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1262        the cross-check on the old pcre_info() function, for the benefit of the
1263        cut-down version of PCRE that is currently imported into Exim.
1265     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1266        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1267        patterns that start (?i) but I don't think that matters. The use of (?i) is
1268        just an example; this all applies to the other options as well.
1270     4. Since libtool seems to echo the compile commands it is issuing, the output
1271        from "make" can be reduced a bit by putting "@" in front of each libtool
1272        compile command.
1274     5. Patch from the folks at Google for configure.in to be a bit more thorough
1275        in checking for a suitable C++ installation before trying to compile the
1276        C++ stuff. This should fix a reported problem when a compiler was present,
1277        but no suitable headers.
1279     6. The man pages all had just "PCRE" as their title. I have changed them to
1280        be the relevant file name. I have also arranged that these names are
1281        retained in the file doc/pcre.txt, which is a concatenation in text format
1282        of all the man pages except the little individual ones for each function.
1284     7. The NON-UNIX-USE file had not been updated for the different set of source
1285        files that come with release 6. I also added a few comments about the C++
1286        wrapper.
1289  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
1290  ---------------------  ---------------------

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