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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 04-Jan-08
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). 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).
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.
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.
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
79    14. Added --file-offsets and --line-offsets to pcregrep.
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
98    19. Added --enable-pcretest-libreadline.
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I removed one of the increments, but Craig sent a
103        later patch that removed the other one (the right fix) and added unit tests
104        that check the return values (which was not done before).
106    21. Several CMake things:
108        (1) Arranged that, when cmake is used on Unix, the libraries end up with
109            the names libpcre and libpcreposix, not just pcre and pcreposix.
111        (2) The above change means that pcretest and pcregrep are now correctly
112            linked with the newly-built libraries, not previously installed ones.
116    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
117        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
118        UTF-8 newline character). The key issue is that the pattern starts .*;
119        this means that the match must be either at the beginning, or after a
120        newline. The bug was in the code for advancing after a failed match and
121        checking that the new position followed a newline. It was not taking
122        account of UTF-8 characters correctly.
124    23. PCRE was behaving differently from Perl in the way it recognized POSIX
125        character classes. PCRE was not treating the sequence [:...:] as a
126        character class unless the ... were all letters. Perl, however, seems to
127        allow any characters between [: and :], though of course it rejects as
128        unknown any "names" that contain non-letters, because all the known class
129        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
130        for example, whereas PCRE did not - it did not recognize a POSIX character
131        class. This seemed a bit dangerous, so the code has been changed to be
132        closer to Perl. The behaviour is not identical to Perl, because PCRE will
133        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
134        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
135        Perl does, and where it didn't before.
137    24. Rewrite so as to remove the single use of %n from pcregrep because in some
138        Windows environments %n is disabled by default.
141    Version 7.4 21-Sep-07
142    ---------------------
144    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
145        means that a class such as [\s] counted as "explicit reference to CR or
146        LF". That isn't really right - the whole point of the change was to try to
147        help when there was an actual mention of one of the two characters. So now
148        the change happens only if \r or \n (or a literal CR or LF) character is
149        encountered.
151    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
152        of both had grown to the point where there were only 3 bits left.
153        Fortunately, there was spare space in the data structure, and so I have
154        moved the internal flags into a new 16-bit field to free up more option
155        bits.
157    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
158        but did not set the internal JCHANGED flag - either of these is enough to
159        control the way the "get" function works - but the PCRE_INFO_JCHANGED
160        facility is supposed to tell if (?J) was ever used, so now (?J) at the
161        start sets both bits.
163    4.  Added options (at build time, compile time, exec time) to change \R from
164        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
166    5.  doc/pcresyntax.html was missing from the distribution.
168    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
169        compatibility, even though it is no longer used.
171    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
172        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
173        windows.h file is present (where different names are used). [This was
174        reversed later after testing - see 16 below.]
176    8.  Changed all #include <config.h> to #include "config.h". There were also
177        some further <pcre.h> cases that I changed to "pcre.h".
179    9.  When pcregrep was used with the --colour option, it missed the line ending
180        sequence off the lines that it output.
182    10. It was pointed out to me that arrays of string pointers cause lots of
183        relocations when a shared library is dynamically loaded. A technique of
184        using a single long string with a table of offsets can drastically reduce
185        these. I have refactored PCRE in four places to do this. The result is
186        dramatic:
188          Originally:                          290
189          After changing UCP table:            187
190          After changing error message table:   43
191          After changing table of "verbs"       36
192          After changing table of Posix names   22
194        Thanks to the folks working on Gregex for glib for this insight.
196    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
197        unicode-properties was also set.
199    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
201    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
202        checked only for CRLF.
204    14. Added casts to pcretest.c to avoid compiler warnings.
206    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
208    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
209        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
210        entirely. This removes changes made in 7 above.
212    17. The CMake files have been updated, and there is now more information about
213        building with CMake in the NON-UNIX-USE document.
216    Version 7.3 28-Aug-07
217    ---------------------
219     1. In the rejigging of the build system that eventually resulted in 7.1, the
220        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
221        brackets there is not right, since it causes compilers to look for an
222        installed pcre.h, not the version that is in the source that is being
223        compiled (which of course may be different). I have changed it back to:
225          #include "pcre.h"
227        I have a vague recollection that the change was concerned with compiling in
228        different directories, but in the new build system, that is taken care of
229        by the VPATH setting the Makefile.
231     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
232        when the subject happened to end in the byte 0x85 (e.g. if the last
233        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
234        characters but of course it shouldn't be taken as a newline when it is part
235        of another character. The bug was that, for an unlimited repeat of . in
236        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
237        characters when looking for a newline.
239     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
241     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
242        in debug output.
244     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
245        long printing in the pcrecpp unittest when running under MinGW.
247     6. ESC_K was left out of the EBCDIC table.
249     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
250        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
251        limit also applies to "virtual nesting" when a pattern is recursive, and in
252        this case 1000 isn't so big. I have been able to remove this limit at the
253        expense of backing off one optimization in certain circumstances. Normally,
254        when pcre_exec() would call its internal match() function recursively and
255        immediately return the result unconditionally, it uses a "tail recursion"
256        feature to save stack. However, when a subpattern that can match an empty
257        string has an unlimited repetition quantifier, it no longer makes this
258        optimization. That gives it a stack frame in which to save the data for
259        checking that an empty string has been matched. Previously this was taken
260        from the 1000-entry workspace that had been reserved. So now there is no
261        explicit limit, but more stack is used.
263     8. Applied Daniel's patches to solve problems with the import/export magic
264        syntax that is required for Windows, and which was going wrong for the
265        pcreposix and pcrecpp parts of the library. These were overlooked when this
266        problem was solved for the main library.
268     9. There were some crude static tests to avoid integer overflow when computing
269        the size of patterns that contain repeated groups with explicit upper
270        limits. As the maximum quantifier is 65535, the maximum group length was
271        set at 30,000 so that the product of these two numbers did not overflow a
272        32-bit integer. However, it turns out that people want to use groups that
273        are longer than 30,000 bytes (though not repeat them that many times).
274        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
275        made it possible to implement the integer overflow checks in a much more
276        dynamic way, which I have now done. The artificial limitation on group
277        length has been removed - we now have only the limit on the total length of
278        the compiled pattern, which depends on the LINK_SIZE setting.
280    10. Fixed a bug in the documentation for get/copy named substring when
281        duplicate names are permitted. If none of the named substrings are set, the
282        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
283        empty string.
285    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
286        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
287        because the ] is interpreted as the first data character and the
288        terminating ] is not found. PCRE has been made compatible with Perl in this
289        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
290        cause memory overwriting.
292    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
293        string has been matched (to stop an infinite loop). It was not recognizing
294        a conditional subpattern that could match an empty string if that
295        subpattern was within another subpattern. For example, it looped when
296        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
297        condition was not nested. This bug has been fixed.
299    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
300        past the start of the subject in the presence of bytes with the top bit
301        set, for example "\x8aBCD".
303    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
304        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
306    14. Optimized (?!) to (*FAIL).
308    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
309        This restricts code points to be within the range 0 to 0x10FFFF, excluding
310        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
311        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
312        does: it's just the validity check that is more restrictive.
314    16. Inserted checks for integer overflows during escape sequence (backslash)
315        processing, and also fixed erroneous offset values for syntax errors during
316        backslash processing.
318    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
319        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
321    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
322        caused an overrun.
324    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
325        something other than just ASCII characters) inside a group that had an
326        unlimited repeat caused a loop at compile time (while checking to see
327        whether the group could match an empty string).
329    20. Debugging a pattern containing \p or \P could cause a crash. For example,
330        [\P{Any}] did so. (Error in the code for printing property names.)
332    21. An orphan \E inside a character class could cause a crash.
334    22. A repeated capturing bracket such as (A)? could cause a wild memory
335        reference during compilation.
337    23. There are several functions in pcre_compile() that scan along a compiled
338        expression for various reasons (e.g. to see if it's fixed length for look
339        behind). There were bugs in these functions when a repeated \p or \P was
340        present in the pattern. These operators have additional parameters compared
341        with \d, etc, and these were not being taken into account when moving along
342        the compiled data. Specifically:
344        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
345            length.
347        (b) An item such as \pL+ within a repeated group could cause crashes or
348            loops.
350        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
351            "reference to non-existent subpattern" error.
353        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
355    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
356        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
358    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
360    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
361        character were causing crashes (broken optimization).
363    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
364        \p or \P) caused a compile-time loop.
366    28. More problems have arisen in unanchored patterns when CRLF is a valid line
367        break. For example, the unstudied pattern [\r\n]A does not match the string
368        "\r\nA" because change 7.0/46 below moves the current point on by two
369        characters after failing to match at the start. However, the pattern \nA
370        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
371        the same is true. There doesn't seem any very clean way out of this, but
372        what I have chosen to do makes the common cases work: PCRE now takes note
373        of whether there can be an explicit match for \r or \n anywhere in the
374        pattern, and if so, 7.0/46 no longer applies. As part of this change,
375        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
376        pattern has explicit CR or LF references.
378    29. Added (*CR) etc for changing newline setting at start of pattern.
381    Version 7.2 19-Jun-07
382    ---------------------
384     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
385        which is apparently normally available under Windows.
387     2. Re-jig the pcregrep tests with different newline settings in an attempt
388        to make them independent of the local environment's newline setting.
390     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
392     4. Some of the "internals" tests were previously cut out when the link size
393        was not 2, because the output contained actual offsets. The recent new
394        "Z" feature of pcretest means that these can be cut out, making the tests
395        usable with all link sizes.
397     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
398        stack recursion. This gives a massive performance boost under BSD, but just
399        a small improvement under Linux. However, it saves one field in the frame
400        in all cases.
402     6. Added more features from the forthcoming Perl 5.10:
404        (a) (?-n) (where n is a string of digits) is a relative subroutine or
405            recursion call. It refers to the nth most recently opened parentheses.
407        (b) (?+n) is also a relative subroutine call; it refers to the nth next
408            to be opened parentheses.
410        (c) Conditions that refer to capturing parentheses can be specified
411            relatively, for example, (?(-2)... or (?(+3)...
413        (d) \K resets the start of the current match so that everything before
414            is not part of it.
416        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
418        (f) \g{name} is another synonym - part of Perl 5.10's unification of
419            reference syntax.
421        (g) (?| introduces a group in which the numbering of parentheses in each
422            alternative starts with the same number.
424        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
426     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
429     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
430        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
431        for detecting groups that can match an empty string.
433     9. A pattern with a very large number of alternatives (more than several
434        hundred) was running out of internal workspace during the pre-compile
435        phase, where pcre_compile() figures out how much memory will be needed. A
436        bit of new cunning has reduced the workspace needed for groups with
437        alternatives. The 1000-alternative test pattern now uses 12 bytes of
438        workspace instead of running out of the 4096 that are available.
440    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
442    11. Applied patch from Google to remove an optimization that didn't quite work.
443        The report of the bug said:
445          pcrecpp::RE("a*").FullMatch("aaa") matches, while
446          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
447          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
449    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
450        it matched the wrong number of bytes.
453    Version 7.1 24-Apr-07
454    ---------------------
456     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
457        that is more "standard", making use of automake and other Autotools. There
458        is some re-arrangement of the files and adjustment of comments consequent
459        on this.
461     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
462        for recursive directory scanning broke on some systems because the files
463        are not scanned in any specific order and on different systems the order
464        was different. A call to "sort" has been inserted into RunGrepTest for the
465        approprate test as a short-term fix. In the longer term there may be an
466        alternative.
468     3. I had an email from Eric Raymond about problems translating some of PCRE's
469        man pages to HTML (despite the fact that I distribute HTML pages, some
470        people do their own conversions for various reasons). The problems
471        concerned the use of low-level troff macros .br and .in. I have therefore
472        removed all such uses from the man pages (some were redundant, some could
473        be replaced by .nf/.fi pairs). The 132html script that I use to generate
474        HTML has been updated to handle .nf/.fi and to complain if it encounters
475        .br or .in.
477     4. Updated comments in configure.ac that get placed in config.h.in and also
478        arranged for config.h to be included in the distribution, with the name
479        config.h.generic, for the benefit of those who have to compile without
480        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
482     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
483        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
484        makevp.bat for the current PCRE, using the additional files
485        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
487     6. A Windows user reported a minor discrepancy with test 2, which turned out
488        to be caused by a trailing space on an input line that had got lost in his
489        copy. The trailing space was an accident, so I've just removed it.
491     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
492        that is needed.
494     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
495        as "const" (a) because they are and (b) because it helps the PHP
496        maintainers who have recently made a script to detect big data structures
497        in the php code that should be moved to the .rodata section. I remembered
498        to update Builducptable as well, so it won't revert if ucptable.h is ever
499        re-created.
501     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
502        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
503        order to be able to cut out the UTF-8 tables in the latter when UTF-8
504        support is not required. This saves 1.5-2K of code, which is important in
505        some applications.
507        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
508        so as not to refer to the tables, even though these functions will never be
509        called when UTF-8 support is disabled. Otherwise there are problems with a
510        shared library.
512    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
514        (a) It was defining its arguments as char * instead of void *.
516        (b) It was assuming that all moves were upwards in memory; this was true
517            a long time ago when I wrote it, but is no longer the case.
519        The emulated memove() is provided for those environments that have neither
520        memmove() nor bcopy(). I didn't think anyone used it these days, but that
521        is clearly not the case, as these two bugs were recently reported.
523    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
524        and Detrail to create the HTML documentation, the .txt form of the man
525        pages, and it removes trailing spaces from listed files. It also creates
526        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
527        case, it wraps all the #defines with #ifndefs. This script should be run
528        before "make dist".
530    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
531        with Unicode property support.
533        (a) For a maximizing quantifier, if the two different cases of the
534            character were of different lengths in their UTF-8 codings (there are
535            some cases like this - I found 11), and the matching function had to
536            back up over a mixture of the two cases, it incorrectly assumed they
537            were both the same length.
539        (b) When PCRE was configured to use the heap rather than the stack for
540            recursion during matching, it was not correctly preserving the data for
541            the other case of a UTF-8 character when checking ahead for a match
542            while processing a minimizing repeat. If the check also involved
543            matching a wide character, but failed, corruption could cause an
544            erroneous result when trying to check for a repeat of the original
545            character.
547    13. Some tidying changes to the testing mechanism:
549        (a) The RunTest script now detects the internal link size and whether there
550            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
551            values substituted by "configure". (The RunGrepTest script already did
552            this for UTF-8.) The configure.ac script no longer substitutes the
553            relevant variables.
555        (b) The debugging options /B and /D in pcretest show the compiled bytecode
556            with length and offset values. This means that the output is different
557            for different internal link sizes. Test 2 is skipped for link sizes
558            other than 2 because of this, bypassing the problem. Unfortunately,
559            there was also a test in test 3 (the locale tests) that used /B and
560            failed for link sizes other than 2. Rather than cut the whole test out,
561            I have added a new /Z option to pcretest that replaces the length and
562            offset values with spaces. This is now used to make test 3 independent
563            of link size. (Test 2 will be tidied up later.)
565    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
566        segmentation fault instead of returning the appropriate error message.
568    15. In multiline mode when the newline sequence was set to "any", the pattern
569        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
570        This doesn't seem right; it now treats the CRLF combination as the line
571        ending, and so does not match in that case. It's only a pattern such as ^$
572        that would hit this one: something like ^ABC$ would have failed after \r
573        and then tried again after \r\n.
575    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
576        in an attempt to make files that differ only in their line terminators
577        compare equal. This works on Linux.
579    17. Under certain error circumstances pcregrep might try to free random memory
580        as it exited. This is now fixed, thanks to valgrind.
582    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
583        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
584        was because its rules for how to advance for /g after matching an empty
585        string at the end of a line did not allow for this case. They now check for
586        it specially.
588    20. pcretest is supposed to handle patterns and data of any length, by
589        extending its buffers when necessary. It was getting this wrong when the
590        buffer for a data line had to be extended.
592    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
593        CRLF as a newline sequence.
595    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
596        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
597        I have nevertheless tidied it up.
599    23. Added some casts to kill warnings from HP-UX ia64 compiler.
601    24. Added a man page for pcre-config.
604    Version 7.0 19-Dec-06
605    ---------------------
607     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
608        moving to gcc 4.1.1.
610     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
611        sys/time.h, which is documented as needed for this function. It doesn't
612        seem to matter on Linux, but it showed up on some releases of OS X.
614     3. It seems that there are systems where bytes whose values are greater than
615        127 match isprint() in the "C" locale. The "C" locale should be the
616        default when a C program starts up. In most systems, only ASCII printing
617        characters match isprint(). This difference caused the output from pcretest
618        to vary, making some of the tests fail. I have changed pcretest so that:
620        (a) When it is outputting text in the compiled version of a pattern, bytes
621            other than 32-126 are always shown as hex escapes.
623        (b) When it is outputting text that is a matched part of a subject string,
624            it does the same, unless a different locale has been set for the match
625            (using the /L modifier). In this case, it uses isprint() to decide.
627     4. Fixed a major bug that caused incorrect computation of the amount of memory
628        required for a compiled pattern when options that changed within the
629        pattern affected the logic of the preliminary scan that determines the
630        length. The relevant options are -x, and -i in UTF-8 mode. The result was
631        that the computed length was too small. The symptoms of this bug were
632        either the PCRE error "internal error: code overflow" from pcre_compile(),
633        or a glibc crash with a message such as "pcretest: free(): invalid next
634        size (fast)". Examples of patterns that provoked this bug (shown in
635        pcretest format) are:
637          /(?-x: )/x
638          /(?x)(?-x: \s*#\s*)/
639          /((?i)[\x{c0}])/8
640          /(?i:[\x{c0}])/8
642        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
643        is now done differently.
645     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
646        wrapper classes; (b) implement a new function in the C++ scanner that is
647        more efficient than the old way of doing things because it avoids levels of
648        recursion in the regex matching; (c) add a paragraph to the documentation
649        for the FullMatch() function.
651     6. The escape sequence \n was being treated as whatever was defined as
652        "newline". Not only was this contrary to the documentation, which states
653        that \n is character 10 (hex 0A), but it also went horribly wrong when
654        "newline" was defined as CRLF. This has been fixed.
656     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
657        was being set to -1 for the "end of line" case (supposedly a value that no
658        character can have). Though this value is never used (the check for end of
659        line is "zero bytes in current character"), it caused compiler complaints.
660        I've changed it to 0xffffffff.
662     8. In pcre_version.c, the version string was being built by a sequence of
663        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
664        string (as it is for production releases) called a macro with an empty
665        argument. The C standard says the result of this is undefined. The gcc
666        compiler treats it as an empty string (which was what was wanted) but it is
667        reported that Visual C gives an error. The source has been hacked around to
668        avoid this problem.
670     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
671        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
672        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
673        of them did).
675    10. Originally, pcretest opened its input and output without "b"; then I was
676        told that "b" was needed in some environments, so it was added for release
677        5.0 to both the input and output. (It makes no difference on Unix-like
678        systems.) Later I was told that it is wrong for the input on Windows. I've
679        now abstracted the modes into two macros, to make it easier to fiddle with
680        them, and removed "b" from the input mode under Windows.
682    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
684    12. Added -help and --help to pcretest as an official way of being reminded
685        of the options.
687    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
688        and pcrecpp.cc because they annoy compilers at high warning levels.
690    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
692    15. Fixed an occurrence of == in configure.ac that should have been = (shell
693        scripts are not C programs :-) and which was not noticed because it works
694        on Linux.
696    16. pcretest is supposed to handle any length of pattern and data line (as one
697        line or as a continued sequence of lines) by extending its input buffer if
698        necessary. This feature was broken for very long pattern lines, leading to
699        a string of junk being passed to pcre_compile() if the pattern was longer
700        than about 50K.
702    17. I have done a major re-factoring of the way pcre_compile() computes the
703        amount of memory needed for a compiled pattern. Previously, there was code
704        that made a preliminary scan of the pattern in order to do this. That was
705        OK when PCRE was new, but as the facilities have expanded, it has become
706        harder and harder to keep it in step with the real compile phase, and there
707        have been a number of bugs (see for example, 4 above). I have now found a
708        cunning way of running the real compile function in a "fake" mode that
709        enables it to compute how much memory it would need, while actually only
710        ever using a few hundred bytes of working memory and without too many
711        tests of the mode. This should make future maintenance and development
712        easier. A side effect of this work is that the limit of 200 on the nesting
713        depth of parentheses has been removed (though this was never a serious
714        limitation, I suspect). However, there is a downside: pcre_compile() now
715        runs more slowly than before (30% or more, depending on the pattern). I
716        hope this isn't a big issue. There is no effect on runtime performance.
718    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
719        newline (only possible for the last line of a file) and it was a
720        pattern that set a locale (followed by /Lsomething), pcretest crashed.
722    19. Added additional timing features to pcretest. (1) The -tm option now times
723        matching only, not compiling. (2) Both -t and -tm can be followed, as a
724        separate command line item, by a number that specifies the number of
725        repeats to use when timing. The default is 50000; this gives better
726        precision, but takes uncomfortably long for very large patterns.
728    20. Extended pcre_study() to be more clever in cases where a branch of a
729        subpattern has no definite first character. For example, (a*|b*)[cd] would
730        previously give no result from pcre_study(). Now it recognizes that the
731        first character must be a, b, c, or d.
733    21. There was an incorrect error "recursive call could loop indefinitely" if
734        a subpattern (or the entire pattern) that was being tested for matching an
735        empty string contained only one non-empty item after a nested subpattern.
736        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
737        incorrectly, because the \d was being skipped in the check.
739    22. The pcretest program now has a new pattern option /B and a command line
740        option -b, which is equivalent to adding /B to every pattern. This causes
741        it to show the compiled bytecode, without the additional information that
742        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
743        is the same as /B/I).
745    23. A new optimization is now able automatically to treat some sequences such
746        as a*b as a*+b. More specifically, if something simple (such as a character
747        or a simple class like \d) has an unlimited quantifier, and is followed by
748        something that cannot possibly match the quantified thing, the quantifier
749        is automatically "possessified".
751    24. A recursive reference to a subpattern whose number was greater than 39
752        went wrong under certain circumstances in UTF-8 mode. This bug could also
753        have affected the operation of pcre_study().
755    25. Realized that a little bit of performance could be had by replacing
756        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
758    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
760    27. Possessive quantifiers such as a++ were previously implemented by turning
761        them into atomic groups such as ($>a+). Now they have their own opcodes,
762        which improves performance. This includes the automatically created ones
763        from 23 above.
765    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
766        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
767        the first matched character to be a colon. This applied both to named and
768        numbered groups.
770    29. The ucpinternal.h header file was missing its idempotency #ifdef.
772    30. I was sent a "project" file called libpcre.a.dev which I understand makes
773        building PCRE on Windows easier, so I have included it in the distribution.
775    31. There is now a check in pcretest against a ridiculously large number being
776        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
777        loop, the loop is abandoned.
779    32. Forward references to subpatterns in conditions such as (?(2)...) where
780        subpattern 2 is defined later cause pcre_compile() to search forwards in
781        the pattern for the relevant set of parentheses. This search went wrong
782        when there were unescaped parentheses in a character class, parentheses
783        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
785    33. "Subroutine" calls and backreferences were previously restricted to
786        referencing subpatterns earlier in the regex. This restriction has now
787        been removed.
789    34. Added a number of extra features that are going to be in Perl 5.10. On the
790        whole, these are just syntactic alternatives for features that PCRE had
791        previously implemented using the Python syntax or my own invention. The
792        other formats are all retained for compatibility.
794        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
795            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
796            also .NET compatible.
798        (b) A recursion or subroutine call to a named group can now be defined as
799            (?&name) as well as (?P>name).
801        (c) A backreference to a named group can now be defined as \k<name> or
802            \k'name' as well as (?P=name). The new forms, as well as being in Perl
803            5.10, are also .NET compatible.
805        (d) A conditional reference to a named group can now use the syntax
806            (?(<name>) or (?('name') as well as (?(name).
808        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
809            groups (named and numbered) that are never evaluated inline, but can be
810            called as "subroutines" from elsewhere. In effect, the DEFINE condition
811            is always false. There may be only one alternative in such a group.
813        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
814            as the simple (?(R). The condition is true only if the most recent
815            recursion is that of the given number or name. It does not search out
816            through the entire recursion stack.
818        (g) The escape \gN or \g{N} has been added, where N is a positive or
819            negative number, specifying an absolute or relative reference.
821    35. Tidied to get rid of some further signed/unsigned compiler warnings and
822        some "unreachable code" warnings.
824    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
825        things, this adds five new scripts.
827    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
828        There were also incompatibilities regarding the handling of \Q..\E inside
829        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
830        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
832    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
833        matches an empty string, and forcibly breaks the loop. There were bugs in
834        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
835        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
836        separate and independent bugs (that affected different cases) have been
837        fixed.
839    39. Refactored the code to abolish the use of different opcodes for small
840        capturing bracket numbers. This is a tidy that I avoided doing when I
841        removed the limit on the number of capturing brackets for 3.5 back in 2001.
842        The new approach is not only tidier, it makes it possible to reduce the
843        memory needed to fix the previous bug (38).
845    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
846        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
847        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
848        mode.
850    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
851        report.
853    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
854        copy construction and assignment in the C++ wrapper.
856    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
857        couple of bugs that could have given wrong results in the "--newline=crlf"
858        case.
860    44. Added a number of casts and did some reorganization of signed/unsigned int
861        variables following suggestions from Dair Grant. Also renamed the variable
862        "this" as "item" because it is a C++ keyword.
864    45. Arranged for dftables to add
866          #include "pcre_internal.h"
868        to pcre_chartables.c because without it, gcc 4.x may remove the array
869        definition from the final binary if PCRE is built into a static library and
870        dead code stripping is activated.
872    46. For an unanchored pattern, if a match attempt fails at the start of a
873        newline sequence, and the newline setting is CRLF or ANY, and the next two
874        characters are CRLF, advance by two characters instead of one.
877    Version 6.7 04-Jul-06
878    ---------------------
880     1. In order to handle tests when input lines are enormously long, pcretest has
881        been re-factored so that it automatically extends its buffers when
882        necessary. The code is crude, but this _is_ just a test program. The
883        default size has been increased from 32K to 50K.
885     2. The code in pcre_study() was using the value of the re argument before
886        testing it for NULL. (Of course, in any sensible call of the function, it
887        won't be NULL.)
889     3. The memmove() emulation function in pcre_internal.h, which is used on
890        systems that lack both memmove() and bcopy() - that is, hardly ever -
891        was missing a "static" storage class specifier.
893     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
894        containing an extended class (one that cannot be represented by a bitmap
895        because it contains high-valued characters or Unicode property items, e.g.
896        [\pZ]). Almost always one would set UTF-8 mode when processing such a
897        pattern, but PCRE should not loop if you do not (it no longer does).
898        [Detail: two cases were found: (a) a repeated subpattern containing an
899        extended class; (b) a recursive reference to a subpattern that followed a
900        previous extended class. It wasn't skipping over the extended class
901        correctly when UTF-8 mode was not set.]
903     5. A negated single-character class was not being recognized as fixed-length
904        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
905        compile error "lookbehind assertion is not fixed length".
907     6. The RunPerlTest auxiliary script was showing an unexpected difference
908        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
909        write a Perl script that can interpret lines of an input file either as
910        byte characters or as UTF-8, which is what "perltest" was being required to
911        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
912        can't do is switch easily at run time between having the "use utf8;" pragma
913        or not. In the end, I fudged it by using the RunPerlTest script to insert
914        "use utf8;" explicitly for the UTF-8 tests.
916     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
917        the end of the subject string, contrary to the documentation and to what
918        Perl does. This was true of both matching functions. Now it matches only at
919        the start of the subject and immediately after *internal* newlines.
921     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
922        a pointer to an int instead of a pointer to an unsigned long int. This
923        caused problems on 64-bit systems.
925     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
926        instance of the 'standard' template library not being so standard".
928    10. There was no check on the number of named subpatterns nor the maximum
929        length of a subpattern name. The product of these values is used to compute
930        the size of the memory block for a compiled pattern. By supplying a very
931        long subpattern name and a large number of named subpatterns, the size
932        computation could be caused to overflow. This is now prevented by limiting
933        the length of names to 32 characters, and the number of named subpatterns
934        to 10,000.
936    11. Subpatterns that are repeated with specific counts have to be replicated in
937        the compiled pattern. The size of memory for this was computed from the
938        length of the subpattern and the repeat count. The latter is limited to
939        65535, but there was no limit on the former, meaning that integer overflow
940        could in principle occur. The compiled length of a repeated subpattern is
941        now limited to 30,000 bytes in order to prevent this.
943    12. Added the optional facility to have named substrings with the same name.
945    13. Added the ability to use a named substring as a condition, using the
946        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
947        are numbers (not recommended). Forward references are permitted.
949    14. Added forward references in named backreferences (if you see what I mean).
951    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
952        pattern could run off the end of the subject. For example, the pattern
953        "(?s)(.{1,5})"8 did this with the subject "ab".
955    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
956        PCRE_CASELESS was set when matching characters that were quantified with ?
957        or *.
959    17. A character class other than a single negated character that had a minimum
960        but no maximum quantifier - for example [ab]{6,} - was not handled
961        correctly by pce_dfa_exec(). It would match only one character.
963    18. A valid (though odd) pattern that looked like a POSIX character
964        class but used an invalid character after [ (for example [[,abc,]]) caused
965        pcre_compile() to give the error "Failed: internal error: code overflow" or
966        in some cases to crash with a glibc free() error. This could even happen if
967        the pattern terminated after [[ but there just happened to be a sequence of
968        letters, a binary zero, and a closing ] in the memory that followed.
970    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
971        over the years. Originally (before any Unicode support), just the bottom 8
972        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
973        output from "man perlunicode" includes this:
975          The regular expression compiler produces polymorphic opcodes.  That
976          is, the pattern adapts to the data and automatically switches to
977          the Unicode character scheme when presented with Unicode data--or
978          instead uses a traditional byte scheme when presented with byte
979          data.
981        Sadly, a wide octal escape does not cause a switch, and in a string with
982        no other multibyte characters, these octal escapes are treated as before.
983        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
984        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
985        Unicode string.
987        I have not perpetrated such confusion in PCRE. Up till now, it took just
988        the bottom 8 bits, as in old Perl. I have now made octal escapes with
989        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
990        translate to the appropriate multibyte character.
992    29. Applied some refactoring to reduce the number of warnings from Microsoft
993        and Borland compilers. This has included removing the fudge introduced
994        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
995        a warning about an unused variable.
997    21. PCRE has not included VT (character 0x0b) in the set of whitespace
998        characters since release 4.0, because Perl (from release 5.004) does not.
999        [Or at least, is documented not to: some releases seem to be in conflict
1000        with the documentation.] However, when a pattern was studied with
1001        pcre_study() and all its branches started with \s, PCRE still included VT
1002        as a possible starting character. Of course, this did no harm; it just
1003        caused an unnecessary match attempt.
1005    22. Removed a now-redundant internal flag bit that recorded the fact that case
1006        dependency changed within the pattern. This was once needed for "required
1007        byte" processing, but is no longer used. This recovers a now-scarce options
1008        bit. Also moved the least significant internal flag bit to the most-
1009        significant bit of the word, which was not previously used (hangover from
1010        the days when it was an int rather than a uint) to free up another bit for
1011        the future.
1013    23. Added support for CRLF line endings as well as CR and LF. As well as the
1014        default being selectable at build time, it can now be changed at runtime
1015        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1016        specify that it is scanning data with non-default line endings.
1018    24. Changed the definition of CXXLINK to make it agree with the definition of
1019        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1021    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1022        recursions. This makes a big different to stack usage for some patterns.
1024    26. If a subpattern containing a named recursion or subroutine reference such
1025        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1026        the space required for the compiled pattern went wrong and gave too small a
1027        value. Depending on the environment, this could lead to "Failed: internal
1028        error: code overflow at offset 49" or "glibc detected double free or
1029        corruption" errors.
1031    27. Applied patches from Google (a) to support the new newline modes and (b) to
1032        advance over multibyte UTF-8 characters in GlobalReplace.
1034    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1035        difference for some implementation of PCRE in some Windows version.
1037    29. Added some extra testing facilities to pcretest:
1039        \q<number>   in a data line sets the "match limit" value
1040        \Q<number>   in a data line sets the "match recursion limt" value
1041        -S <number>  sets the stack size, where <number> is in megabytes
1043        The -S option isn't available for Windows.
1046    Version 6.6 06-Feb-06
1047    ---------------------
1049     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1050        in pcreposix.h. I have copied the definition from pcre.h.
1052     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1053        because pcre.h is no longer a built file.
1055     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1056        not normally included in the compiled code.
1059    Version 6.5 01-Feb-06
1060    ---------------------
1062     1. When using the partial match feature with pcre_dfa_exec(), it was not
1063        anchoring the second and subsequent partial matches at the new starting
1064        point. This could lead to incorrect results. For example, with the pattern
1065        /1234/, partially matching against "123" and then "a4" gave a match.
1067     2. Changes to pcregrep:
1069        (a) All non-match returns from pcre_exec() were being treated as failures
1070            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1071            error message is output. Some extra information is given for the
1072            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1073            probably the only errors that are likely to be caused by users (by
1074            specifying a regex that has nested indefinite repeats, for instance).
1075            If there are more than 20 of these errors, pcregrep is abandoned.
1077        (b) A binary zero was treated as data while matching, but terminated the
1078            output line if it was written out. This has been fixed: binary zeroes
1079            are now no different to any other data bytes.
1081        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1082            used to set a locale for matching. The --locale=xxxx long option has
1083            been added (no short equivalent) to specify a locale explicitly on the
1084            pcregrep command, overriding the environment variables.
1086        (d) When -B was used with -n, some line numbers in the output were one less
1087            than they should have been.
1089        (e) Added the -o (--only-matching) option.
1091        (f) If -A or -C was used with -c (count only), some lines of context were
1092            accidentally printed for the final match.
1094        (g) Added the -H (--with-filename) option.
1096        (h) The combination of options -rh failed to suppress file names for files
1097            that were found from directory arguments.
1099        (i) Added the -D (--devices) and -d (--directories) options.
1101        (j) Added the -F (--fixed-strings) option.
1103        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1105        (l) Added the --colo(u)r option.
1107        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1108            is not present by default.
1110     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1111        items such as (?R) or (?1), when the recursion could match a number of
1112        alternatives. If it matched one of the alternatives, but subsequently,
1113        outside the recursion, there was a failure, the code tried to back up into
1114        the recursion. However, because of the way PCRE is implemented, this is not
1115        possible, and the result was an incorrect result from the match.
1117        In order to prevent this happening, the specification of recursion has
1118        been changed so that all such subpatterns are automatically treated as
1119        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1121     4. I had overlooked the fact that, in some locales, there are characters for
1122        which isalpha() is true but neither isupper() nor islower() are true. In
1123        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1124        and ordfeminine) are like this. This affected the treatment of \w and \W
1125        when they appeared in character classes, but not when they appeared outside
1126        a character class. The bit map for "word" characters is now created
1127        separately from the results of isalnum() instead of just taking it from the
1128        upper, lower, and digit maps. (Plus the underscore character, of course.)
1130     5. The above bug also affected the handling of POSIX character classes such as
1131        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1132        permanent tables. Instead, the bit maps for such a class were previously
1133        created as the appropriate unions of the upper, lower, and digit bitmaps.
1134        Now they are created by subtraction from the [[:word:]] class, which has
1135        its own bitmap.
1137     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1138        It is created by subtracting the vertical space characters (\x09, \x0a,
1139        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1140        subtraction was done in the overall bitmap for a character class, meaning
1141        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1142        be recognized. This bug has been fixed.
1144     7. Patches from the folks at Google:
1146          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1147          real life, but is still worth protecting against".
1149          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1150          regular expressions".
1152          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1153          have it.
1155          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1156          "configure" and the latter not, in order to fix a problem somebody had
1157          with compiling the Arg class on HP-UX.
1159          (e) Improve the error-handling of the C++ wrapper a little bit.
1161          (f) New tests for checking recursion limiting.
1163     8. The pcre_memmove() function, which is used only if the environment does not
1164        have a standard memmove() function (and is therefore rarely compiled),
1165        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1166        returning a result (though PCRE never actually uses the result).
1168     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1169        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1170        returned instead of calling malloc() with an overflowing number that would
1171        most likely cause subsequent chaos.
1173    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1175    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1176        with this option is matched, the nmatch and pmatch options of regexec() are
1177        ignored.
1179    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1180        provided in case anyone wants to the the POSIX interface with UTF-8
1181        strings.
1183    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1184        C++ linking (needed for some HP-UX environments).
1186    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1187        (unused parameter) and in the pcre_printint() function (omitted "default"
1188        switch label when the default is to do nothing).
1190    15. Added some code to make it possible, when PCRE is compiled as a C++
1191        library, to replace subject pointers for pcre_exec() with a smart pointer
1192        class, thus making it possible to process discontinuous strings.
1194    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1195        much the same function. They were added by different people who were trying
1196        to make PCRE easy to compile on non-Unix systems. It has been suggested
1197        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1198        for compiling on Windows systems. I have therefore replaced it with
1199        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1200        defaults to "extern" for C or "extern C" for C++, which works fine on
1201        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1202        SCOPE with something explicit in config.h. In addition:
1204        (a) pcreposix.h still had just "extern" instead of either of these macros;
1205            I have replaced it with PCRE_DATA_SCOPE.
1207        (b) Functions such as _pcre_xclass(), which are internal to the library,
1208            but external in the C sense, all had PCRE_EXPORT in their definitions.
1209            This is apparently wrong for the Windows case, so I have removed it.
1210            (It makes no difference on Unix-like systems.)
1212    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1213        of recursive calls to match(). This is different to MATCH_LIMIT because
1214        that limits the total number of calls to match(), not all of which increase
1215        the depth of recursion. Limiting the recursion depth limits the amount of
1216        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1217        when PCRE is compiled, and changed at run time. A patch from Google adds
1218        this functionality to the C++ interface.
1220    18. Changes to the handling of Unicode character properties:
1222        (a) Updated the table to Unicode 4.1.0.
1224        (b) Recognize characters that are not in the table as "Cn" (undefined).
1226        (c) I revised the way the table is implemented to a much improved format
1227            which includes recognition of ranges. It now supports the ranges that
1228            are defined in UnicodeData.txt, and it also amalgamates other
1229            characters into ranges. This has reduced the number of entries in the
1230            table from around 16,000 to around 3,000, thus reducing its size
1231            considerably. I realized I did not need to use a tree structure after
1232            all - a binary chop search is just as efficient. Having reduced the
1233            number of entries, I extended their size from 6 bytes to 8 bytes to
1234            allow for more data.
1236        (d) Added support for Unicode script names via properties such as \p{Han}.
1238    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1239        matching that character.
1241    20. When matching a repeated Unicode property with a minimum greater than zero,
1242        (for example \pL{2,}), PCRE could look past the end of the subject if it
1243        reached it while seeking the minimum number of characters. This could
1244        happen only if some of the characters were more than one byte long, because
1245        there is a check for at least the minimum number of bytes.
1247    21. Refactored the implementation of \p and \P so as to be more general, to
1248        allow for more different types of property in future. This has changed the
1249        compiled form incompatibly. Anybody with saved compiled patterns that use
1250        \p or \P will have to recompile them.
1252    22. Added "Any" and "L&" to the supported property types.
1254    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1255        but give a compile time error if the value is greater than 0xff.
1257    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1258        accidentally not being installed or uninstalled.
1260    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1261        made were to insert the current release number. This seemed silly, because
1262        it made things harder for people building PCRE on systems that don't run
1263        "configure". I have turned pcre.h into a distributed file, no longer built
1264        by "configure", with the version identification directly included. There is
1265        no longer a pcre.h.in file.
1267        However, this change necessitated a change to the pcre-config script as
1268        well. It is built from pcre-config.in, and one of the substitutions was the
1269        release number. I have updated configure.ac so that ./configure now finds
1270        the release number by grepping pcre.h.
1272    26. Added the ability to run the tests under valgrind.
1275    Version 6.4 05-Sep-05
1276    ---------------------
1278     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1279        "--" to be printed when multiple files were scanned, even when none of the
1280        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1281        consider it to be a bug, and have restored the previous behaviour.
1283     2. A couple of code tidies to get rid of compiler warnings.
1285     3. The pcretest program used to cheat by referring to symbols in the library
1286        whose names begin with _pcre_. These are internal symbols that are not
1287        really supposed to be visible externally, and in some environments it is
1288        possible to suppress them. The cheating is now confined to including
1289        certain files from the library's source, which is a bit cleaner.
1291     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1292        file's purpose clearer.
1294     5. Reorganized pcre_ucp_findchar().
1297  Version 6.3 15-Aug-05  Version 6.3 15-Aug-05
1298  ---------------------  ---------------------

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