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revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC revision 295 by ph10, Mon Dec 31 17:00:24 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 31-Dec-07
5    ---------------------
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). 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 have removed one of the increments.
104    21. Several CMake things:
106        (1) Arranged that, when cmake is used on Unix, the libraries end up with
107            the names libpcre and libpcreposix, not just pcre and pcreposix.
109        (2) The above change means that pcretest and pcregrep are now correctly
110            linked with the newly-built libraries, not previously installed ones.
114    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
115        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
116        UTF-8 newline character). The key issue is that the pattern starts .*;
117        this means that the match must be either at the beginning, or after a
118        newline. The bug was in the code for advancing after a failed match and
119        checking that the new position followed a newline. It was not taking
120        account of UTF-8 characters correctly.
122    23. PCRE was behaving differently from Perl in the way it recognized POSIX
123        character classes. PCRE was not treating the sequence [:...:] as a
124        character class unless the ... were all letters. Perl, however, seems to
125        allow any characters between [: and :], though of course it rejects as
126        unknown any "names" that contain non-letters, because all the known class
127        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
128        for example, whereas PCRE did not - it did not recognize a POSIX character
129        class. This seemed a bit dangerous, so the code has been changed to be
130        closer to Perl. The behaviour is not identical to Perl, because PCRE will
131        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
132        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
133        Perl does, and where it didn't before.
136    Version 7.4 21-Sep-07
137    ---------------------
139    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
140        means that a class such as [\s] counted as "explicit reference to CR or
141        LF". That isn't really right - the whole point of the change was to try to
142        help when there was an actual mention of one of the two characters. So now
143        the change happens only if \r or \n (or a literal CR or LF) character is
144        encountered.
146    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
147        of both had grown to the point where there were only 3 bits left.
148        Fortunately, there was spare space in the data structure, and so I have
149        moved the internal flags into a new 16-bit field to free up more option
150        bits.
152    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
153        but did not set the internal JCHANGED flag - either of these is enough to
154        control the way the "get" function works - but the PCRE_INFO_JCHANGED
155        facility is supposed to tell if (?J) was ever used, so now (?J) at the
156        start sets both bits.
158    4.  Added options (at build time, compile time, exec time) to change \R from
159        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
161    5.  doc/pcresyntax.html was missing from the distribution.
163    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
164        compatibility, even though it is no longer used.
166    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
167        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
168        windows.h file is present (where different names are used). [This was
169        reversed later after testing - see 16 below.]
171    8.  Changed all #include <config.h> to #include "config.h". There were also
172        some further <pcre.h> cases that I changed to "pcre.h".
174    9.  When pcregrep was used with the --colour option, it missed the line ending
175        sequence off the lines that it output.
177    10. It was pointed out to me that arrays of string pointers cause lots of
178        relocations when a shared library is dynamically loaded. A technique of
179        using a single long string with a table of offsets can drastically reduce
180        these. I have refactored PCRE in four places to do this. The result is
181        dramatic:
183          Originally:                          290
184          After changing UCP table:            187
185          After changing error message table:   43
186          After changing table of "verbs"       36
187          After changing table of Posix names   22
189        Thanks to the folks working on Gregex for glib for this insight.
191    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
192        unicode-properties was also set.
194    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
196    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
197        checked only for CRLF.
199    14. Added casts to pcretest.c to avoid compiler warnings.
201    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
203    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
204        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
205        entirely. This removes changes made in 7 above.
207    17. The CMake files have been updated, and there is now more information about
208        building with CMake in the NON-UNIX-USE document.
211    Version 7.3 28-Aug-07
212    ---------------------
214     1. In the rejigging of the build system that eventually resulted in 7.1, the
215        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
216        brackets there is not right, since it causes compilers to look for an
217        installed pcre.h, not the version that is in the source that is being
218        compiled (which of course may be different). I have changed it back to:
220          #include "pcre.h"
222        I have a vague recollection that the change was concerned with compiling in
223        different directories, but in the new build system, that is taken care of
224        by the VPATH setting the Makefile.
226     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
227        when the subject happened to end in the byte 0x85 (e.g. if the last
228        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
229        characters but of course it shouldn't be taken as a newline when it is part
230        of another character. The bug was that, for an unlimited repeat of . in
231        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
232        characters when looking for a newline.
234     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
236     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
237        in debug output.
239     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
240        long printing in the pcrecpp unittest when running under MinGW.
242     6. ESC_K was left out of the EBCDIC table.
244     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
245        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
246        limit also applies to "virtual nesting" when a pattern is recursive, and in
247        this case 1000 isn't so big. I have been able to remove this limit at the
248        expense of backing off one optimization in certain circumstances. Normally,
249        when pcre_exec() would call its internal match() function recursively and
250        immediately return the result unconditionally, it uses a "tail recursion"
251        feature to save stack. However, when a subpattern that can match an empty
252        string has an unlimited repetition quantifier, it no longer makes this
253        optimization. That gives it a stack frame in which to save the data for
254        checking that an empty string has been matched. Previously this was taken
255        from the 1000-entry workspace that had been reserved. So now there is no
256        explicit limit, but more stack is used.
258     8. Applied Daniel's patches to solve problems with the import/export magic
259        syntax that is required for Windows, and which was going wrong for the
260        pcreposix and pcrecpp parts of the library. These were overlooked when this
261        problem was solved for the main library.
263     9. There were some crude static tests to avoid integer overflow when computing
264        the size of patterns that contain repeated groups with explicit upper
265        limits. As the maximum quantifier is 65535, the maximum group length was
266        set at 30,000 so that the product of these two numbers did not overflow a
267        32-bit integer. However, it turns out that people want to use groups that
268        are longer than 30,000 bytes (though not repeat them that many times).
269        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
270        made it possible to implement the integer overflow checks in a much more
271        dynamic way, which I have now done. The artificial limitation on group
272        length has been removed - we now have only the limit on the total length of
273        the compiled pattern, which depends on the LINK_SIZE setting.
275    10. Fixed a bug in the documentation for get/copy named substring when
276        duplicate names are permitted. If none of the named substrings are set, the
277        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
278        empty string.
280    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
281        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
282        because the ] is interpreted as the first data character and the
283        terminating ] is not found. PCRE has been made compatible with Perl in this
284        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
285        cause memory overwriting.
287    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
288        string has been matched (to stop an infinite loop). It was not recognizing
289        a conditional subpattern that could match an empty string if that
290        subpattern was within another subpattern. For example, it looped when
291        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
292        condition was not nested. This bug has been fixed.
294    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
295        past the start of the subject in the presence of bytes with the top bit
296        set, for example "\x8aBCD".
298    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
299        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
301    14. Optimized (?!) to (*FAIL).
303    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
304        This restricts code points to be within the range 0 to 0x10FFFF, excluding
305        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
306        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
307        does: it's just the validity check that is more restrictive.
309    16. Inserted checks for integer overflows during escape sequence (backslash)
310        processing, and also fixed erroneous offset values for syntax errors during
311        backslash processing.
313    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
314        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
316    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
317        caused an overrun.
319    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
320        something other than just ASCII characters) inside a group that had an
321        unlimited repeat caused a loop at compile time (while checking to see
322        whether the group could match an empty string).
324    20. Debugging a pattern containing \p or \P could cause a crash. For example,
325        [\P{Any}] did so. (Error in the code for printing property names.)
327    21. An orphan \E inside a character class could cause a crash.
329    22. A repeated capturing bracket such as (A)? could cause a wild memory
330        reference during compilation.
332    23. There are several functions in pcre_compile() that scan along a compiled
333        expression for various reasons (e.g. to see if it's fixed length for look
334        behind). There were bugs in these functions when a repeated \p or \P was
335        present in the pattern. These operators have additional parameters compared
336        with \d, etc, and these were not being taken into account when moving along
337        the compiled data. Specifically:
339        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
340            length.
342        (b) An item such as \pL+ within a repeated group could cause crashes or
343            loops.
345        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
346            "reference to non-existent subpattern" error.
348        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
350    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
351        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
353    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
355    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
356        character were causing crashes (broken optimization).
358    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
359        \p or \P) caused a compile-time loop.
361    28. More problems have arisen in unanchored patterns when CRLF is a valid line
362        break. For example, the unstudied pattern [\r\n]A does not match the string
363        "\r\nA" because change 7.0/46 below moves the current point on by two
364        characters after failing to match at the start. However, the pattern \nA
365        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
366        the same is true. There doesn't seem any very clean way out of this, but
367        what I have chosen to do makes the common cases work: PCRE now takes note
368        of whether there can be an explicit match for \r or \n anywhere in the
369        pattern, and if so, 7.0/46 no longer applies. As part of this change,
370        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
371        pattern has explicit CR or LF references.
373    29. Added (*CR) etc for changing newline setting at start of pattern.
376    Version 7.2 19-Jun-07
377    ---------------------
379     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
380        which is apparently normally available under Windows.
382     2. Re-jig the pcregrep tests with different newline settings in an attempt
383        to make them independent of the local environment's newline setting.
385     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
387     4. Some of the "internals" tests were previously cut out when the link size
388        was not 2, because the output contained actual offsets. The recent new
389        "Z" feature of pcretest means that these can be cut out, making the tests
390        usable with all link sizes.
392     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
393        stack recursion. This gives a massive performance boost under BSD, but just
394        a small improvement under Linux. However, it saves one field in the frame
395        in all cases.
397     6. Added more features from the forthcoming Perl 5.10:
399        (a) (?-n) (where n is a string of digits) is a relative subroutine or
400            recursion call. It refers to the nth most recently opened parentheses.
402        (b) (?+n) is also a relative subroutine call; it refers to the nth next
403            to be opened parentheses.
405        (c) Conditions that refer to capturing parentheses can be specified
406            relatively, for example, (?(-2)... or (?(+3)...
408        (d) \K resets the start of the current match so that everything before
409            is not part of it.
411        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
413        (f) \g{name} is another synonym - part of Perl 5.10's unification of
414            reference syntax.
416        (g) (?| introduces a group in which the numbering of parentheses in each
417            alternative starts with the same number.
419        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
421     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
424     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
425        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
426        for detecting groups that can match an empty string.
428     9. A pattern with a very large number of alternatives (more than several
429        hundred) was running out of internal workspace during the pre-compile
430        phase, where pcre_compile() figures out how much memory will be needed. A
431        bit of new cunning has reduced the workspace needed for groups with
432        alternatives. The 1000-alternative test pattern now uses 12 bytes of
433        workspace instead of running out of the 4096 that are available.
435    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
437    11. Applied patch from Google to remove an optimization that didn't quite work.
438        The report of the bug said:
440          pcrecpp::RE("a*").FullMatch("aaa") matches, while
441          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
442          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
444    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
445        it matched the wrong number of bytes.
448    Version 7.1 24-Apr-07
449    ---------------------
451     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
452        that is more "standard", making use of automake and other Autotools. There
453        is some re-arrangement of the files and adjustment of comments consequent
454        on this.
456     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
457        for recursive directory scanning broke on some systems because the files
458        are not scanned in any specific order and on different systems the order
459        was different. A call to "sort" has been inserted into RunGrepTest for the
460        approprate test as a short-term fix. In the longer term there may be an
461        alternative.
463     3. I had an email from Eric Raymond about problems translating some of PCRE's
464        man pages to HTML (despite the fact that I distribute HTML pages, some
465        people do their own conversions for various reasons). The problems
466        concerned the use of low-level troff macros .br and .in. I have therefore
467        removed all such uses from the man pages (some were redundant, some could
468        be replaced by .nf/.fi pairs). The 132html script that I use to generate
469        HTML has been updated to handle .nf/.fi and to complain if it encounters
470        .br or .in.
472     4. Updated comments in configure.ac that get placed in config.h.in and also
473        arranged for config.h to be included in the distribution, with the name
474        config.h.generic, for the benefit of those who have to compile without
475        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
477     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
478        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
479        makevp.bat for the current PCRE, using the additional files
480        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
482     6. A Windows user reported a minor discrepancy with test 2, which turned out
483        to be caused by a trailing space on an input line that had got lost in his
484        copy. The trailing space was an accident, so I've just removed it.
486     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
487        that is needed.
489     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
490        as "const" (a) because they are and (b) because it helps the PHP
491        maintainers who have recently made a script to detect big data structures
492        in the php code that should be moved to the .rodata section. I remembered
493        to update Builducptable as well, so it won't revert if ucptable.h is ever
494        re-created.
496     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
497        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
498        order to be able to cut out the UTF-8 tables in the latter when UTF-8
499        support is not required. This saves 1.5-2K of code, which is important in
500        some applications.
502        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
503        so as not to refer to the tables, even though these functions will never be
504        called when UTF-8 support is disabled. Otherwise there are problems with a
505        shared library.
507    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
509        (a) It was defining its arguments as char * instead of void *.
511        (b) It was assuming that all moves were upwards in memory; this was true
512            a long time ago when I wrote it, but is no longer the case.
514        The emulated memove() is provided for those environments that have neither
515        memmove() nor bcopy(). I didn't think anyone used it these days, but that
516        is clearly not the case, as these two bugs were recently reported.
518    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
519        and Detrail to create the HTML documentation, the .txt form of the man
520        pages, and it removes trailing spaces from listed files. It also creates
521        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
522        case, it wraps all the #defines with #ifndefs. This script should be run
523        before "make dist".
525    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
526        with Unicode property support.
528        (a) For a maximizing quantifier, if the two different cases of the
529            character were of different lengths in their UTF-8 codings (there are
530            some cases like this - I found 11), and the matching function had to
531            back up over a mixture of the two cases, it incorrectly assumed they
532            were both the same length.
534        (b) When PCRE was configured to use the heap rather than the stack for
535            recursion during matching, it was not correctly preserving the data for
536            the other case of a UTF-8 character when checking ahead for a match
537            while processing a minimizing repeat. If the check also involved
538            matching a wide character, but failed, corruption could cause an
539            erroneous result when trying to check for a repeat of the original
540            character.
542    13. Some tidying changes to the testing mechanism:
544        (a) The RunTest script now detects the internal link size and whether there
545            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
546            values substituted by "configure". (The RunGrepTest script already did
547            this for UTF-8.) The configure.ac script no longer substitutes the
548            relevant variables.
550        (b) The debugging options /B and /D in pcretest show the compiled bytecode
551            with length and offset values. This means that the output is different
552            for different internal link sizes. Test 2 is skipped for link sizes
553            other than 2 because of this, bypassing the problem. Unfortunately,
554            there was also a test in test 3 (the locale tests) that used /B and
555            failed for link sizes other than 2. Rather than cut the whole test out,
556            I have added a new /Z option to pcretest that replaces the length and
557            offset values with spaces. This is now used to make test 3 independent
558            of link size. (Test 2 will be tidied up later.)
560    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
561        segmentation fault instead of returning the appropriate error message.
563    15. In multiline mode when the newline sequence was set to "any", the pattern
564        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
565        This doesn't seem right; it now treats the CRLF combination as the line
566        ending, and so does not match in that case. It's only a pattern such as ^$
567        that would hit this one: something like ^ABC$ would have failed after \r
568        and then tried again after \r\n.
570    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
571        in an attempt to make files that differ only in their line terminators
572        compare equal. This works on Linux.
574    17. Under certain error circumstances pcregrep might try to free random memory
575        as it exited. This is now fixed, thanks to valgrind.
577    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
578        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
579        was because its rules for how to advance for /g after matching an empty
580        string at the end of a line did not allow for this case. They now check for
581        it specially.
583    20. pcretest is supposed to handle patterns and data of any length, by
584        extending its buffers when necessary. It was getting this wrong when the
585        buffer for a data line had to be extended.
587    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
588        CRLF as a newline sequence.
590    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
591        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
592        I have nevertheless tidied it up.
594    23. Added some casts to kill warnings from HP-UX ia64 compiler.
596    24. Added a man page for pcre-config.
599    Version 7.0 19-Dec-06
600    ---------------------
602     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
603        moving to gcc 4.1.1.
605     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
606        sys/time.h, which is documented as needed for this function. It doesn't
607        seem to matter on Linux, but it showed up on some releases of OS X.
609     3. It seems that there are systems where bytes whose values are greater than
610        127 match isprint() in the "C" locale. The "C" locale should be the
611        default when a C program starts up. In most systems, only ASCII printing
612        characters match isprint(). This difference caused the output from pcretest
613        to vary, making some of the tests fail. I have changed pcretest so that:
615        (a) When it is outputting text in the compiled version of a pattern, bytes
616            other than 32-126 are always shown as hex escapes.
618        (b) When it is outputting text that is a matched part of a subject string,
619            it does the same, unless a different locale has been set for the match
620            (using the /L modifier). In this case, it uses isprint() to decide.
622     4. Fixed a major bug that caused incorrect computation of the amount of memory
623        required for a compiled pattern when options that changed within the
624        pattern affected the logic of the preliminary scan that determines the
625        length. The relevant options are -x, and -i in UTF-8 mode. The result was
626        that the computed length was too small. The symptoms of this bug were
627        either the PCRE error "internal error: code overflow" from pcre_compile(),
628        or a glibc crash with a message such as "pcretest: free(): invalid next
629        size (fast)". Examples of patterns that provoked this bug (shown in
630        pcretest format) are:
632          /(?-x: )/x
633          /(?x)(?-x: \s*#\s*)/
634          /((?i)[\x{c0}])/8
635          /(?i:[\x{c0}])/8
637        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
638        is now done differently.
640     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
641        wrapper classes; (b) implement a new function in the C++ scanner that is
642        more efficient than the old way of doing things because it avoids levels of
643        recursion in the regex matching; (c) add a paragraph to the documentation
644        for the FullMatch() function.
646     6. The escape sequence \n was being treated as whatever was defined as
647        "newline". Not only was this contrary to the documentation, which states
648        that \n is character 10 (hex 0A), but it also went horribly wrong when
649        "newline" was defined as CRLF. This has been fixed.
651     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
652        was being set to -1 for the "end of line" case (supposedly a value that no
653        character can have). Though this value is never used (the check for end of
654        line is "zero bytes in current character"), it caused compiler complaints.
655        I've changed it to 0xffffffff.
657     8. In pcre_version.c, the version string was being built by a sequence of
658        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
659        string (as it is for production releases) called a macro with an empty
660        argument. The C standard says the result of this is undefined. The gcc
661        compiler treats it as an empty string (which was what was wanted) but it is
662        reported that Visual C gives an error. The source has been hacked around to
663        avoid this problem.
665     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
666        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
667        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
668        of them did).
670    10. Originally, pcretest opened its input and output without "b"; then I was
671        told that "b" was needed in some environments, so it was added for release
672        5.0 to both the input and output. (It makes no difference on Unix-like
673        systems.) Later I was told that it is wrong for the input on Windows. I've
674        now abstracted the modes into two macros, to make it easier to fiddle with
675        them, and removed "b" from the input mode under Windows.
677    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
679    12. Added -help and --help to pcretest as an official way of being reminded
680        of the options.
682    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
683        and pcrecpp.cc because they annoy compilers at high warning levels.
685    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
687    15. Fixed an occurrence of == in configure.ac that should have been = (shell
688        scripts are not C programs :-) and which was not noticed because it works
689        on Linux.
691    16. pcretest is supposed to handle any length of pattern and data line (as one
692        line or as a continued sequence of lines) by extending its input buffer if
693        necessary. This feature was broken for very long pattern lines, leading to
694        a string of junk being passed to pcre_compile() if the pattern was longer
695        than about 50K.
697    17. I have done a major re-factoring of the way pcre_compile() computes the
698        amount of memory needed for a compiled pattern. Previously, there was code
699        that made a preliminary scan of the pattern in order to do this. That was
700        OK when PCRE was new, but as the facilities have expanded, it has become
701        harder and harder to keep it in step with the real compile phase, and there
702        have been a number of bugs (see for example, 4 above). I have now found a
703        cunning way of running the real compile function in a "fake" mode that
704        enables it to compute how much memory it would need, while actually only
705        ever using a few hundred bytes of working memory and without too many
706        tests of the mode. This should make future maintenance and development
707        easier. A side effect of this work is that the limit of 200 on the nesting
708        depth of parentheses has been removed (though this was never a serious
709        limitation, I suspect). However, there is a downside: pcre_compile() now
710        runs more slowly than before (30% or more, depending on the pattern). I
711        hope this isn't a big issue. There is no effect on runtime performance.
713    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
714        newline (only possible for the last line of a file) and it was a
715        pattern that set a locale (followed by /Lsomething), pcretest crashed.
717    19. Added additional timing features to pcretest. (1) The -tm option now times
718        matching only, not compiling. (2) Both -t and -tm can be followed, as a
719        separate command line item, by a number that specifies the number of
720        repeats to use when timing. The default is 50000; this gives better
721        precision, but takes uncomfortably long for very large patterns.
723    20. Extended pcre_study() to be more clever in cases where a branch of a
724        subpattern has no definite first character. For example, (a*|b*)[cd] would
725        previously give no result from pcre_study(). Now it recognizes that the
726        first character must be a, b, c, or d.
728    21. There was an incorrect error "recursive call could loop indefinitely" if
729        a subpattern (or the entire pattern) that was being tested for matching an
730        empty string contained only one non-empty item after a nested subpattern.
731        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
732        incorrectly, because the \d was being skipped in the check.
734    22. The pcretest program now has a new pattern option /B and a command line
735        option -b, which is equivalent to adding /B to every pattern. This causes
736        it to show the compiled bytecode, without the additional information that
737        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
738        is the same as /B/I).
740    23. A new optimization is now able automatically to treat some sequences such
741        as a*b as a*+b. More specifically, if something simple (such as a character
742        or a simple class like \d) has an unlimited quantifier, and is followed by
743        something that cannot possibly match the quantified thing, the quantifier
744        is automatically "possessified".
746    24. A recursive reference to a subpattern whose number was greater than 39
747        went wrong under certain circumstances in UTF-8 mode. This bug could also
748        have affected the operation of pcre_study().
750    25. Realized that a little bit of performance could be had by replacing
751        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
753    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
755    27. Possessive quantifiers such as a++ were previously implemented by turning
756        them into atomic groups such as ($>a+). Now they have their own opcodes,
757        which improves performance. This includes the automatically created ones
758        from 23 above.
760    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
761        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
762        the first matched character to be a colon. This applied both to named and
763        numbered groups.
765    29. The ucpinternal.h header file was missing its idempotency #ifdef.
767    30. I was sent a "project" file called libpcre.a.dev which I understand makes
768        building PCRE on Windows easier, so I have included it in the distribution.
770    31. There is now a check in pcretest against a ridiculously large number being
771        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
772        loop, the loop is abandoned.
774    32. Forward references to subpatterns in conditions such as (?(2)...) where
775        subpattern 2 is defined later cause pcre_compile() to search forwards in
776        the pattern for the relevant set of parentheses. This search went wrong
777        when there were unescaped parentheses in a character class, parentheses
778        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
780    33. "Subroutine" calls and backreferences were previously restricted to
781        referencing subpatterns earlier in the regex. This restriction has now
782        been removed.
784    34. Added a number of extra features that are going to be in Perl 5.10. On the
785        whole, these are just syntactic alternatives for features that PCRE had
786        previously implemented using the Python syntax or my own invention. The
787        other formats are all retained for compatibility.
789        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
790            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
791            also .NET compatible.
793        (b) A recursion or subroutine call to a named group can now be defined as
794            (?&name) as well as (?P>name).
796        (c) A backreference to a named group can now be defined as \k<name> or
797            \k'name' as well as (?P=name). The new forms, as well as being in Perl
798            5.10, are also .NET compatible.
800        (d) A conditional reference to a named group can now use the syntax
801            (?(<name>) or (?('name') as well as (?(name).
803        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
804            groups (named and numbered) that are never evaluated inline, but can be
805            called as "subroutines" from elsewhere. In effect, the DEFINE condition
806            is always false. There may be only one alternative in such a group.
808        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
809            as the simple (?(R). The condition is true only if the most recent
810            recursion is that of the given number or name. It does not search out
811            through the entire recursion stack.
813        (g) The escape \gN or \g{N} has been added, where N is a positive or
814            negative number, specifying an absolute or relative reference.
816    35. Tidied to get rid of some further signed/unsigned compiler warnings and
817        some "unreachable code" warnings.
819    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
820        things, this adds five new scripts.
822    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
823        There were also incompatibilities regarding the handling of \Q..\E inside
824        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
825        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
827    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
828        matches an empty string, and forcibly breaks the loop. There were bugs in
829        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
830        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
831        separate and independent bugs (that affected different cases) have been
832        fixed.
834    39. Refactored the code to abolish the use of different opcodes for small
835        capturing bracket numbers. This is a tidy that I avoided doing when I
836        removed the limit on the number of capturing brackets for 3.5 back in 2001.
837        The new approach is not only tidier, it makes it possible to reduce the
838        memory needed to fix the previous bug (38).
840    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
841        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
842        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
843        mode.
845    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
846        report.
848    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
849        copy construction and assignment in the C++ wrapper.
851    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
852        couple of bugs that could have given wrong results in the "--newline=crlf"
853        case.
855    44. Added a number of casts and did some reorganization of signed/unsigned int
856        variables following suggestions from Dair Grant. Also renamed the variable
857        "this" as "item" because it is a C++ keyword.
859    45. Arranged for dftables to add
861          #include "pcre_internal.h"
863        to pcre_chartables.c because without it, gcc 4.x may remove the array
864        definition from the final binary if PCRE is built into a static library and
865        dead code stripping is activated.
867    46. For an unanchored pattern, if a match attempt fails at the start of a
868        newline sequence, and the newline setting is CRLF or ANY, and the next two
869        characters are CRLF, advance by two characters instead of one.
872  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
873  ---------------------  ---------------------

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