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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.6 19-Jan-08
5    ---------------------
7    1.  A character class containing a very large number of characters with
8        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9        overflow.
11    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
12        HAVE_LONG_LONG is not defined.
14    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
15        bring them up to date and include new features. This patch includes:
17        - Fixed PH's badly added libz and libbz2 support.
18        - Fixed a problem with static linking.
19        - Added pcredemo.
20        - Fixed dftables problem and added an option.
21        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
22            HAVE_LONG_LONG.
23        - Added readline support for pcretest.
24        - Added an listing of the option settings after cmake has run.
26    4.  A user submitted a patch to Makefile that makes it easy to created a dll
27        under mingw. I added stuff to Makefile.am that cause it to include this
28        special target, without affecting anything else.
31    Version 7.5 10-Jan-08
32    ---------------------
34    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
35        values in parens when parsing an RE using the C++ wrapper."
37    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
38        Characters greater than 255 were excluded from the class instead of being
39        included.
41    3.  The same bug as (2) above applied to negated POSIX classes such as
42        [:^space:].
44    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
45        defined or documented. It seems to have been a typo for PCRE_STATIC, so
46        I have changed it.
48    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
49        first named subpattern) and a construct such as (?&a) would reference the
50        first named subpattern whose name started with "a" (in other words, the
51        length check was missing). Both these problems are fixed. "Subpattern name
52        expected" is now given for (?&) (a zero-length name), and this patch also
53        makes it give the same error for \k'' (previously it complained that that
54        was a reference to a non-existent subpattern).
56    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
57        this is right because (?- can be followed by option settings as well as by
58        digits. I have, however, made the messages clearer.
60    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
61        than the number used in the conditional) now cause a compile-time error.
62        This is actually not compatible with Perl, which accepts such patterns, but
63        treats the conditional as always being FALSE (as PCRE used to), but it
64        seems to me that giving a diagnostic is better.
66    8.  Change "alphameric" to the more common word "alphanumeric" in comments
67        and messages.
69    9.  Fix two occurrences of "backslash" in comments that should have been
70        "backspace".
72    10. Remove two redundant lines of code that can never be obeyed (their function
73        was moved elsewhere).
75    11. The program that makes PCRE's Unicode character property table had a bug
76        which caused it to generate incorrect table entries for sequences of
77        characters that have the same character type, but are in different scripts.
78        It amalgamated them into a single range, with the script of the first of
79        them. In other words, some characters were in the wrong script. There were
80        thirteen such cases, affecting characters in the following ranges:
82          U+002b0 - U+002c1
83          U+0060c - U+0060d
84          U+0061e - U+00612
85          U+0064b - U+0065e
86          U+0074d - U+0076d
87          U+01800 - U+01805
88          U+01d00 - U+01d77
89          U+01d9b - U+01dbf
90          U+0200b - U+0200f
91          U+030fc - U+030fe
92          U+03260 - U+0327f
93          U+0fb46 - U+0fbb1
94          U+10450 - U+1049d
96    12. The -o option (show only the matching part of a line) for pcregrep was not
97        compatible with GNU grep in that, if there was more than one match in a
98        line, it showed only the first of them. It now behaves in the same way as
99        GNU grep.
101    13. If the -o and -v options were combined for pcregrep, it printed a blank
102        line for every non-matching line. GNU grep prints nothing, and pcregrep now
103        does the same. The return code can be used to tell if there were any
104        non-matching lines.
106    14. Added --file-offsets and --line-offsets to pcregrep.
108    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
109        infinitely looping recursion. The bug was that positive lookaheads were not
110        being skipped when checking for a possible empty match (negative lookaheads
111        and both kinds of lookbehind were skipped).
113    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
114        inclusion of <windows.h> to before rather than after the definition of
115        INVALID_FILE_ATTRIBUTES (patch from David Byron).
117    17. Specifying a possessive quantifier with a specific limit for a Unicode
118        character property caused pcre_compile() to compile bad code, which led at
119        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
120        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
121        caused the error; without that there was no problem.
123    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
125    19. Added --enable-pcretest-libreadline.
127    20. In pcrecpp.cc, the variable 'count' was incremented twice in
128        RE::GlobalReplace(). As a result, the number of replacements returned was
129        double what it should be. I removed one of the increments, but Craig sent a
130        later patch that removed the other one (the right fix) and added unit tests
131        that check the return values (which was not done before).
133    21. Several CMake things:
135        (1) Arranged that, when cmake is used on Unix, the libraries end up with
136            the names libpcre and libpcreposix, not just pcre and pcreposix.
138        (2) The above change means that pcretest and pcregrep are now correctly
139            linked with the newly-built libraries, not previously installed ones.
143    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
144        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
145        UTF-8 newline character). The key issue is that the pattern starts .*;
146        this means that the match must be either at the beginning, or after a
147        newline. The bug was in the code for advancing after a failed match and
148        checking that the new position followed a newline. It was not taking
149        account of UTF-8 characters correctly.
151    23. PCRE was behaving differently from Perl in the way it recognized POSIX
152        character classes. PCRE was not treating the sequence [:...:] as a
153        character class unless the ... were all letters. Perl, however, seems to
154        allow any characters between [: and :], though of course it rejects as
155        unknown any "names" that contain non-letters, because all the known class
156        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
157        for example, whereas PCRE did not - it did not recognize a POSIX character
158        class. This seemed a bit dangerous, so the code has been changed to be
159        closer to Perl. The behaviour is not identical to Perl, because PCRE will
160        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
161        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
162        Perl does, and where it didn't before.
164    24. Rewrite so as to remove the single use of %n from pcregrep because in some
165        Windows environments %n is disabled by default.
168    Version 7.4 21-Sep-07
169    ---------------------
171    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
172        means that a class such as [\s] counted as "explicit reference to CR or
173        LF". That isn't really right - the whole point of the change was to try to
174        help when there was an actual mention of one of the two characters. So now
175        the change happens only if \r or \n (or a literal CR or LF) character is
176        encountered.
178    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
179        of both had grown to the point where there were only 3 bits left.
180        Fortunately, there was spare space in the data structure, and so I have
181        moved the internal flags into a new 16-bit field to free up more option
182        bits.
184    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
185        but did not set the internal JCHANGED flag - either of these is enough to
186        control the way the "get" function works - but the PCRE_INFO_JCHANGED
187        facility is supposed to tell if (?J) was ever used, so now (?J) at the
188        start sets both bits.
190    4.  Added options (at build time, compile time, exec time) to change \R from
191        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
193    5.  doc/pcresyntax.html was missing from the distribution.
195    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
196        compatibility, even though it is no longer used.
198    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
199        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
200        windows.h file is present (where different names are used). [This was
201        reversed later after testing - see 16 below.]
203    8.  Changed all #include <config.h> to #include "config.h". There were also
204        some further <pcre.h> cases that I changed to "pcre.h".
206    9.  When pcregrep was used with the --colour option, it missed the line ending
207        sequence off the lines that it output.
209    10. It was pointed out to me that arrays of string pointers cause lots of
210        relocations when a shared library is dynamically loaded. A technique of
211        using a single long string with a table of offsets can drastically reduce
212        these. I have refactored PCRE in four places to do this. The result is
213        dramatic:
215          Originally:                          290
216          After changing UCP table:            187
217          After changing error message table:   43
218          After changing table of "verbs"       36
219          After changing table of Posix names   22
221        Thanks to the folks working on Gregex for glib for this insight.
223    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
224        unicode-properties was also set.
226    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
228    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
229        checked only for CRLF.
231    14. Added casts to pcretest.c to avoid compiler warnings.
233    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
235    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
236        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
237        entirely. This removes changes made in 7 above.
239    17. The CMake files have been updated, and there is now more information about
240        building with CMake in the NON-UNIX-USE document.
243    Version 7.3 28-Aug-07
244    ---------------------
246     1. In the rejigging of the build system that eventually resulted in 7.1, the
247        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
248        brackets there is not right, since it causes compilers to look for an
249        installed pcre.h, not the version that is in the source that is being
250        compiled (which of course may be different). I have changed it back to:
252          #include "pcre.h"
254        I have a vague recollection that the change was concerned with compiling in
255        different directories, but in the new build system, that is taken care of
256        by the VPATH setting the Makefile.
258     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
259        when the subject happened to end in the byte 0x85 (e.g. if the last
260        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
261        characters but of course it shouldn't be taken as a newline when it is part
262        of another character. The bug was that, for an unlimited repeat of . in
263        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
264        characters when looking for a newline.
266     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
268     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
269        in debug output.
271     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
272        long printing in the pcrecpp unittest when running under MinGW.
274     6. ESC_K was left out of the EBCDIC table.
276     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
277        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
278        limit also applies to "virtual nesting" when a pattern is recursive, and in
279        this case 1000 isn't so big. I have been able to remove this limit at the
280        expense of backing off one optimization in certain circumstances. Normally,
281        when pcre_exec() would call its internal match() function recursively and
282        immediately return the result unconditionally, it uses a "tail recursion"
283        feature to save stack. However, when a subpattern that can match an empty
284        string has an unlimited repetition quantifier, it no longer makes this
285        optimization. That gives it a stack frame in which to save the data for
286        checking that an empty string has been matched. Previously this was taken
287        from the 1000-entry workspace that had been reserved. So now there is no
288        explicit limit, but more stack is used.
290     8. Applied Daniel's patches to solve problems with the import/export magic
291        syntax that is required for Windows, and which was going wrong for the
292        pcreposix and pcrecpp parts of the library. These were overlooked when this
293        problem was solved for the main library.
295     9. There were some crude static tests to avoid integer overflow when computing
296        the size of patterns that contain repeated groups with explicit upper
297        limits. As the maximum quantifier is 65535, the maximum group length was
298        set at 30,000 so that the product of these two numbers did not overflow a
299        32-bit integer. However, it turns out that people want to use groups that
300        are longer than 30,000 bytes (though not repeat them that many times).
301        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
302        made it possible to implement the integer overflow checks in a much more
303        dynamic way, which I have now done. The artificial limitation on group
304        length has been removed - we now have only the limit on the total length of
305        the compiled pattern, which depends on the LINK_SIZE setting.
307    10. Fixed a bug in the documentation for get/copy named substring when
308        duplicate names are permitted. If none of the named substrings are set, the
309        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
310        empty string.
312    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
313        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
314        because the ] is interpreted as the first data character and the
315        terminating ] is not found. PCRE has been made compatible with Perl in this
316        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
317        cause memory overwriting.
319    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
320        string has been matched (to stop an infinite loop). It was not recognizing
321        a conditional subpattern that could match an empty string if that
322        subpattern was within another subpattern. For example, it looped when
323        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
324        condition was not nested. This bug has been fixed.
326    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
327        past the start of the subject in the presence of bytes with the top bit
328        set, for example "\x8aBCD".
330    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
331        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
333    14. Optimized (?!) to (*FAIL).
335    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
336        This restricts code points to be within the range 0 to 0x10FFFF, excluding
337        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
338        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
339        does: it's just the validity check that is more restrictive.
341    16. Inserted checks for integer overflows during escape sequence (backslash)
342        processing, and also fixed erroneous offset values for syntax errors during
343        backslash processing.
345    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
346        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
348    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
349        caused an overrun.
351    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
352        something other than just ASCII characters) inside a group that had an
353        unlimited repeat caused a loop at compile time (while checking to see
354        whether the group could match an empty string).
356    20. Debugging a pattern containing \p or \P could cause a crash. For example,
357        [\P{Any}] did so. (Error in the code for printing property names.)
359    21. An orphan \E inside a character class could cause a crash.
361    22. A repeated capturing bracket such as (A)? could cause a wild memory
362        reference during compilation.
364    23. There are several functions in pcre_compile() that scan along a compiled
365        expression for various reasons (e.g. to see if it's fixed length for look
366        behind). There were bugs in these functions when a repeated \p or \P was
367        present in the pattern. These operators have additional parameters compared
368        with \d, etc, and these were not being taken into account when moving along
369        the compiled data. Specifically:
371        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
372            length.
374        (b) An item such as \pL+ within a repeated group could cause crashes or
375            loops.
377        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
378            "reference to non-existent subpattern" error.
380        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
382    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
383        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
385    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
387    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
388        character were causing crashes (broken optimization).
390    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
391        \p or \P) caused a compile-time loop.
393    28. More problems have arisen in unanchored patterns when CRLF is a valid line
394        break. For example, the unstudied pattern [\r\n]A does not match the string
395        "\r\nA" because change 7.0/46 below moves the current point on by two
396        characters after failing to match at the start. However, the pattern \nA
397        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
398        the same is true. There doesn't seem any very clean way out of this, but
399        what I have chosen to do makes the common cases work: PCRE now takes note
400        of whether there can be an explicit match for \r or \n anywhere in the
401        pattern, and if so, 7.0/46 no longer applies. As part of this change,
402        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
403        pattern has explicit CR or LF references.
405    29. Added (*CR) etc for changing newline setting at start of pattern.
408    Version 7.2 19-Jun-07
409    ---------------------
411     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
412        which is apparently normally available under Windows.
414     2. Re-jig the pcregrep tests with different newline settings in an attempt
415        to make them independent of the local environment's newline setting.
417     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
419     4. Some of the "internals" tests were previously cut out when the link size
420        was not 2, because the output contained actual offsets. The recent new
421        "Z" feature of pcretest means that these can be cut out, making the tests
422        usable with all link sizes.
424     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
425        stack recursion. This gives a massive performance boost under BSD, but just
426        a small improvement under Linux. However, it saves one field in the frame
427        in all cases.
429     6. Added more features from the forthcoming Perl 5.10:
431        (a) (?-n) (where n is a string of digits) is a relative subroutine or
432            recursion call. It refers to the nth most recently opened parentheses.
434        (b) (?+n) is also a relative subroutine call; it refers to the nth next
435            to be opened parentheses.
437        (c) Conditions that refer to capturing parentheses can be specified
438            relatively, for example, (?(-2)... or (?(+3)...
440        (d) \K resets the start of the current match so that everything before
441            is not part of it.
443        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
445        (f) \g{name} is another synonym - part of Perl 5.10's unification of
446            reference syntax.
448        (g) (?| introduces a group in which the numbering of parentheses in each
449            alternative starts with the same number.
451        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
453     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
456     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
457        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
458        for detecting groups that can match an empty string.
460     9. A pattern with a very large number of alternatives (more than several
461        hundred) was running out of internal workspace during the pre-compile
462        phase, where pcre_compile() figures out how much memory will be needed. A
463        bit of new cunning has reduced the workspace needed for groups with
464        alternatives. The 1000-alternative test pattern now uses 12 bytes of
465        workspace instead of running out of the 4096 that are available.
467    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
469    11. Applied patch from Google to remove an optimization that didn't quite work.
470        The report of the bug said:
472          pcrecpp::RE("a*").FullMatch("aaa") matches, while
473          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
474          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
476    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
477        it matched the wrong number of bytes.
480    Version 7.1 24-Apr-07
481    ---------------------
483     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
484        that is more "standard", making use of automake and other Autotools. There
485        is some re-arrangement of the files and adjustment of comments consequent
486        on this.
488     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
489        for recursive directory scanning broke on some systems because the files
490        are not scanned in any specific order and on different systems the order
491        was different. A call to "sort" has been inserted into RunGrepTest for the
492        approprate test as a short-term fix. In the longer term there may be an
493        alternative.
495     3. I had an email from Eric Raymond about problems translating some of PCRE's
496        man pages to HTML (despite the fact that I distribute HTML pages, some
497        people do their own conversions for various reasons). The problems
498        concerned the use of low-level troff macros .br and .in. I have therefore
499        removed all such uses from the man pages (some were redundant, some could
500        be replaced by .nf/.fi pairs). The 132html script that I use to generate
501        HTML has been updated to handle .nf/.fi and to complain if it encounters
502        .br or .in.
504     4. Updated comments in configure.ac that get placed in config.h.in and also
505        arranged for config.h to be included in the distribution, with the name
506        config.h.generic, for the benefit of those who have to compile without
507        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
509     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
510        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
511        makevp.bat for the current PCRE, using the additional files
512        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
514     6. A Windows user reported a minor discrepancy with test 2, which turned out
515        to be caused by a trailing space on an input line that had got lost in his
516        copy. The trailing space was an accident, so I've just removed it.
518     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
519        that is needed.
521     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
522        as "const" (a) because they are and (b) because it helps the PHP
523        maintainers who have recently made a script to detect big data structures
524        in the php code that should be moved to the .rodata section. I remembered
525        to update Builducptable as well, so it won't revert if ucptable.h is ever
526        re-created.
528     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
529        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
530        order to be able to cut out the UTF-8 tables in the latter when UTF-8
531        support is not required. This saves 1.5-2K of code, which is important in
532        some applications.
534        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
535        so as not to refer to the tables, even though these functions will never be
536        called when UTF-8 support is disabled. Otherwise there are problems with a
537        shared library.
539    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
541        (a) It was defining its arguments as char * instead of void *.
543        (b) It was assuming that all moves were upwards in memory; this was true
544            a long time ago when I wrote it, but is no longer the case.
546        The emulated memove() is provided for those environments that have neither
547        memmove() nor bcopy(). I didn't think anyone used it these days, but that
548        is clearly not the case, as these two bugs were recently reported.
550    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
551        and Detrail to create the HTML documentation, the .txt form of the man
552        pages, and it removes trailing spaces from listed files. It also creates
553        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
554        case, it wraps all the #defines with #ifndefs. This script should be run
555        before "make dist".
557    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
558        with Unicode property support.
560        (a) For a maximizing quantifier, if the two different cases of the
561            character were of different lengths in their UTF-8 codings (there are
562            some cases like this - I found 11), and the matching function had to
563            back up over a mixture of the two cases, it incorrectly assumed they
564            were both the same length.
566        (b) When PCRE was configured to use the heap rather than the stack for
567            recursion during matching, it was not correctly preserving the data for
568            the other case of a UTF-8 character when checking ahead for a match
569            while processing a minimizing repeat. If the check also involved
570            matching a wide character, but failed, corruption could cause an
571            erroneous result when trying to check for a repeat of the original
572            character.
574    13. Some tidying changes to the testing mechanism:
576        (a) The RunTest script now detects the internal link size and whether there
577            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
578            values substituted by "configure". (The RunGrepTest script already did
579            this for UTF-8.) The configure.ac script no longer substitutes the
580            relevant variables.
582        (b) The debugging options /B and /D in pcretest show the compiled bytecode
583            with length and offset values. This means that the output is different
584            for different internal link sizes. Test 2 is skipped for link sizes
585            other than 2 because of this, bypassing the problem. Unfortunately,
586            there was also a test in test 3 (the locale tests) that used /B and
587            failed for link sizes other than 2. Rather than cut the whole test out,
588            I have added a new /Z option to pcretest that replaces the length and
589            offset values with spaces. This is now used to make test 3 independent
590            of link size. (Test 2 will be tidied up later.)
592    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
593        segmentation fault instead of returning the appropriate error message.
595    15. In multiline mode when the newline sequence was set to "any", the pattern
596        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
597        This doesn't seem right; it now treats the CRLF combination as the line
598        ending, and so does not match in that case. It's only a pattern such as ^$
599        that would hit this one: something like ^ABC$ would have failed after \r
600        and then tried again after \r\n.
602    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
603        in an attempt to make files that differ only in their line terminators
604        compare equal. This works on Linux.
606    17. Under certain error circumstances pcregrep might try to free random memory
607        as it exited. This is now fixed, thanks to valgrind.
609    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
610        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
611        was because its rules for how to advance for /g after matching an empty
612        string at the end of a line did not allow for this case. They now check for
613        it specially.
615    20. pcretest is supposed to handle patterns and data of any length, by
616        extending its buffers when necessary. It was getting this wrong when the
617        buffer for a data line had to be extended.
619    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
620        CRLF as a newline sequence.
622    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
623        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
624        I have nevertheless tidied it up.
626    23. Added some casts to kill warnings from HP-UX ia64 compiler.
628    24. Added a man page for pcre-config.
631    Version 7.0 19-Dec-06
632    ---------------------
634     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
635        moving to gcc 4.1.1.
637     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
638        sys/time.h, which is documented as needed for this function. It doesn't
639        seem to matter on Linux, but it showed up on some releases of OS X.
641     3. It seems that there are systems where bytes whose values are greater than
642        127 match isprint() in the "C" locale. The "C" locale should be the
643        default when a C program starts up. In most systems, only ASCII printing
644        characters match isprint(). This difference caused the output from pcretest
645        to vary, making some of the tests fail. I have changed pcretest so that:
647        (a) When it is outputting text in the compiled version of a pattern, bytes
648            other than 32-126 are always shown as hex escapes.
650        (b) When it is outputting text that is a matched part of a subject string,
651            it does the same, unless a different locale has been set for the match
652            (using the /L modifier). In this case, it uses isprint() to decide.
654     4. Fixed a major bug that caused incorrect computation of the amount of memory
655        required for a compiled pattern when options that changed within the
656        pattern affected the logic of the preliminary scan that determines the
657        length. The relevant options are -x, and -i in UTF-8 mode. The result was
658        that the computed length was too small. The symptoms of this bug were
659        either the PCRE error "internal error: code overflow" from pcre_compile(),
660        or a glibc crash with a message such as "pcretest: free(): invalid next
661        size (fast)". Examples of patterns that provoked this bug (shown in
662        pcretest format) are:
664          /(?-x: )/x
665          /(?x)(?-x: \s*#\s*)/
666          /((?i)[\x{c0}])/8
667          /(?i:[\x{c0}])/8
669        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
670        is now done differently.
672     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
673        wrapper classes; (b) implement a new function in the C++ scanner that is
674        more efficient than the old way of doing things because it avoids levels of
675        recursion in the regex matching; (c) add a paragraph to the documentation
676        for the FullMatch() function.
678     6. The escape sequence \n was being treated as whatever was defined as
679        "newline". Not only was this contrary to the documentation, which states
680        that \n is character 10 (hex 0A), but it also went horribly wrong when
681        "newline" was defined as CRLF. This has been fixed.
683     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
684        was being set to -1 for the "end of line" case (supposedly a value that no
685        character can have). Though this value is never used (the check for end of
686        line is "zero bytes in current character"), it caused compiler complaints.
687        I've changed it to 0xffffffff.
689     8. In pcre_version.c, the version string was being built by a sequence of
690        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
691        string (as it is for production releases) called a macro with an empty
692        argument. The C standard says the result of this is undefined. The gcc
693        compiler treats it as an empty string (which was what was wanted) but it is
694        reported that Visual C gives an error. The source has been hacked around to
695        avoid this problem.
697     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
698        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
699        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
700        of them did).
702    10. Originally, pcretest opened its input and output without "b"; then I was
703        told that "b" was needed in some environments, so it was added for release
704        5.0 to both the input and output. (It makes no difference on Unix-like
705        systems.) Later I was told that it is wrong for the input on Windows. I've
706        now abstracted the modes into two macros, to make it easier to fiddle with
707        them, and removed "b" from the input mode under Windows.
709    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
711    12. Added -help and --help to pcretest as an official way of being reminded
712        of the options.
714    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
715        and pcrecpp.cc because they annoy compilers at high warning levels.
717    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
719    15. Fixed an occurrence of == in configure.ac that should have been = (shell
720        scripts are not C programs :-) and which was not noticed because it works
721        on Linux.
723    16. pcretest is supposed to handle any length of pattern and data line (as one
724        line or as a continued sequence of lines) by extending its input buffer if
725        necessary. This feature was broken for very long pattern lines, leading to
726        a string of junk being passed to pcre_compile() if the pattern was longer
727        than about 50K.
729    17. I have done a major re-factoring of the way pcre_compile() computes the
730        amount of memory needed for a compiled pattern. Previously, there was code
731        that made a preliminary scan of the pattern in order to do this. That was
732        OK when PCRE was new, but as the facilities have expanded, it has become
733        harder and harder to keep it in step with the real compile phase, and there
734        have been a number of bugs (see for example, 4 above). I have now found a
735        cunning way of running the real compile function in a "fake" mode that
736        enables it to compute how much memory it would need, while actually only
737        ever using a few hundred bytes of working memory and without too many
738        tests of the mode. This should make future maintenance and development
739        easier. A side effect of this work is that the limit of 200 on the nesting
740        depth of parentheses has been removed (though this was never a serious
741        limitation, I suspect). However, there is a downside: pcre_compile() now
742        runs more slowly than before (30% or more, depending on the pattern). I
743        hope this isn't a big issue. There is no effect on runtime performance.
745    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
746        newline (only possible for the last line of a file) and it was a
747        pattern that set a locale (followed by /Lsomething), pcretest crashed.
749    19. Added additional timing features to pcretest. (1) The -tm option now times
750        matching only, not compiling. (2) Both -t and -tm can be followed, as a
751        separate command line item, by a number that specifies the number of
752        repeats to use when timing. The default is 50000; this gives better
753        precision, but takes uncomfortably long for very large patterns.
755    20. Extended pcre_study() to be more clever in cases where a branch of a
756        subpattern has no definite first character. For example, (a*|b*)[cd] would
757        previously give no result from pcre_study(). Now it recognizes that the
758        first character must be a, b, c, or d.
760    21. There was an incorrect error "recursive call could loop indefinitely" if
761        a subpattern (or the entire pattern) that was being tested for matching an
762        empty string contained only one non-empty item after a nested subpattern.
763        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
764        incorrectly, because the \d was being skipped in the check.
766    22. The pcretest program now has a new pattern option /B and a command line
767        option -b, which is equivalent to adding /B to every pattern. This causes
768        it to show the compiled bytecode, without the additional information that
769        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
770        is the same as /B/I).
772    23. A new optimization is now able automatically to treat some sequences such
773        as a*b as a*+b. More specifically, if something simple (such as a character
774        or a simple class like \d) has an unlimited quantifier, and is followed by
775        something that cannot possibly match the quantified thing, the quantifier
776        is automatically "possessified".
778    24. A recursive reference to a subpattern whose number was greater than 39
779        went wrong under certain circumstances in UTF-8 mode. This bug could also
780        have affected the operation of pcre_study().
782    25. Realized that a little bit of performance could be had by replacing
783        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
785    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
787    27. Possessive quantifiers such as a++ were previously implemented by turning
788        them into atomic groups such as ($>a+). Now they have their own opcodes,
789        which improves performance. This includes the automatically created ones
790        from 23 above.
792    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
793        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
794        the first matched character to be a colon. This applied both to named and
795        numbered groups.
797    29. The ucpinternal.h header file was missing its idempotency #ifdef.
799    30. I was sent a "project" file called libpcre.a.dev which I understand makes
800        building PCRE on Windows easier, so I have included it in the distribution.
802    31. There is now a check in pcretest against a ridiculously large number being
803        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
804        loop, the loop is abandoned.
806    32. Forward references to subpatterns in conditions such as (?(2)...) where
807        subpattern 2 is defined later cause pcre_compile() to search forwards in
808        the pattern for the relevant set of parentheses. This search went wrong
809        when there were unescaped parentheses in a character class, parentheses
810        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
812    33. "Subroutine" calls and backreferences were previously restricted to
813        referencing subpatterns earlier in the regex. This restriction has now
814        been removed.
816    34. Added a number of extra features that are going to be in Perl 5.10. On the
817        whole, these are just syntactic alternatives for features that PCRE had
818        previously implemented using the Python syntax or my own invention. The
819        other formats are all retained for compatibility.
821        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
822            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
823            also .NET compatible.
825        (b) A recursion or subroutine call to a named group can now be defined as
826            (?&name) as well as (?P>name).
828        (c) A backreference to a named group can now be defined as \k<name> or
829            \k'name' as well as (?P=name). The new forms, as well as being in Perl
830            5.10, are also .NET compatible.
832        (d) A conditional reference to a named group can now use the syntax
833            (?(<name>) or (?('name') as well as (?(name).
835        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
836            groups (named and numbered) that are never evaluated inline, but can be
837            called as "subroutines" from elsewhere. In effect, the DEFINE condition
838            is always false. There may be only one alternative in such a group.
840        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
841            as the simple (?(R). The condition is true only if the most recent
842            recursion is that of the given number or name. It does not search out
843            through the entire recursion stack.
845        (g) The escape \gN or \g{N} has been added, where N is a positive or
846            negative number, specifying an absolute or relative reference.
848    35. Tidied to get rid of some further signed/unsigned compiler warnings and
849        some "unreachable code" warnings.
851    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
852        things, this adds five new scripts.
854    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
855        There were also incompatibilities regarding the handling of \Q..\E inside
856        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
857        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
859    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
860        matches an empty string, and forcibly breaks the loop. There were bugs in
861        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
862        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
863        separate and independent bugs (that affected different cases) have been
864        fixed.
866    39. Refactored the code to abolish the use of different opcodes for small
867        capturing bracket numbers. This is a tidy that I avoided doing when I
868        removed the limit on the number of capturing brackets for 3.5 back in 2001.
869        The new approach is not only tidier, it makes it possible to reduce the
870        memory needed to fix the previous bug (38).
872    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
873        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
874        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
875        mode.
877    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
878        report.
880    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
881        copy construction and assignment in the C++ wrapper.
883    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
884        couple of bugs that could have given wrong results in the "--newline=crlf"
885        case.
887    44. Added a number of casts and did some reorganization of signed/unsigned int
888        variables following suggestions from Dair Grant. Also renamed the variable
889        "this" as "item" because it is a C++ keyword.
891    45. Arranged for dftables to add
893          #include "pcre_internal.h"
895        to pcre_chartables.c because without it, gcc 4.x may remove the array
896        definition from the final binary if PCRE is built into a static library and
897        dead code stripping is activated.
899    46. For an unanchored pattern, if a match attempt fails at the start of a
900        newline sequence, and the newline setting is CRLF or ANY, and the next two
901        characters are CRLF, advance by two characters instead of one.
904  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
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