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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 292 by ph10, Thu Dec 27 09:27:23 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 27-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.
115    Version 7.4 21-Sep-07
116    ---------------------
118    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
119        means that a class such as [\s] counted as "explicit reference to CR or
120        LF". That isn't really right - the whole point of the change was to try to
121        help when there was an actual mention of one of the two characters. So now
122        the change happens only if \r or \n (or a literal CR or LF) character is
123        encountered.
125    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
126        of both had grown to the point where there were only 3 bits left.
127        Fortunately, there was spare space in the data structure, and so I have
128        moved the internal flags into a new 16-bit field to free up more option
129        bits.
131    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
132        but did not set the internal JCHANGED flag - either of these is enough to
133        control the way the "get" function works - but the PCRE_INFO_JCHANGED
134        facility is supposed to tell if (?J) was ever used, so now (?J) at the
135        start sets both bits.
137    4.  Added options (at build time, compile time, exec time) to change \R from
138        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
140    5.  doc/pcresyntax.html was missing from the distribution.
142    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
143        compatibility, even though it is no longer used.
145    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
146        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
147        windows.h file is present (where different names are used). [This was
148        reversed later after testing - see 16 below.]
150    8.  Changed all #include <config.h> to #include "config.h". There were also
151        some further <pcre.h> cases that I changed to "pcre.h".
153    9.  When pcregrep was used with the --colour option, it missed the line ending
154        sequence off the lines that it output.
156    10. It was pointed out to me that arrays of string pointers cause lots of
157        relocations when a shared library is dynamically loaded. A technique of
158        using a single long string with a table of offsets can drastically reduce
159        these. I have refactored PCRE in four places to do this. The result is
160        dramatic:
162          Originally:                          290
163          After changing UCP table:            187
164          After changing error message table:   43
165          After changing table of "verbs"       36
166          After changing table of Posix names   22
168        Thanks to the folks working on Gregex for glib for this insight.
170    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
171        unicode-properties was also set.
173    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
175    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
176        checked only for CRLF.
178    14. Added casts to pcretest.c to avoid compiler warnings.
180    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
182    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
183        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
184        entirely. This removes changes made in 7 above.
186    17. The CMake files have been updated, and there is now more information about
187        building with CMake in the NON-UNIX-USE document.
190    Version 7.3 28-Aug-07
191    ---------------------
193     1. In the rejigging of the build system that eventually resulted in 7.1, the
194        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
195        brackets there is not right, since it causes compilers to look for an
196        installed pcre.h, not the version that is in the source that is being
197        compiled (which of course may be different). I have changed it back to:
199          #include "pcre.h"
201        I have a vague recollection that the change was concerned with compiling in
202        different directories, but in the new build system, that is taken care of
203        by the VPATH setting the Makefile.
205     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
206        when the subject happened to end in the byte 0x85 (e.g. if the last
207        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
208        characters but of course it shouldn't be taken as a newline when it is part
209        of another character. The bug was that, for an unlimited repeat of . in
210        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
211        characters when looking for a newline.
213     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
215     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
216        in debug output.
218     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
219        long printing in the pcrecpp unittest when running under MinGW.
221     6. ESC_K was left out of the EBCDIC table.
223     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
224        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
225        limit also applies to "virtual nesting" when a pattern is recursive, and in
226        this case 1000 isn't so big. I have been able to remove this limit at the
227        expense of backing off one optimization in certain circumstances. Normally,
228        when pcre_exec() would call its internal match() function recursively and
229        immediately return the result unconditionally, it uses a "tail recursion"
230        feature to save stack. However, when a subpattern that can match an empty
231        string has an unlimited repetition quantifier, it no longer makes this
232        optimization. That gives it a stack frame in which to save the data for
233        checking that an empty string has been matched. Previously this was taken
234        from the 1000-entry workspace that had been reserved. So now there is no
235        explicit limit, but more stack is used.
237     8. Applied Daniel's patches to solve problems with the import/export magic
238        syntax that is required for Windows, and which was going wrong for the
239        pcreposix and pcrecpp parts of the library. These were overlooked when this
240        problem was solved for the main library.
242     9. There were some crude static tests to avoid integer overflow when computing
243        the size of patterns that contain repeated groups with explicit upper
244        limits. As the maximum quantifier is 65535, the maximum group length was
245        set at 30,000 so that the product of these two numbers did not overflow a
246        32-bit integer. However, it turns out that people want to use groups that
247        are longer than 30,000 bytes (though not repeat them that many times).
248        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
249        made it possible to implement the integer overflow checks in a much more
250        dynamic way, which I have now done. The artificial limitation on group
251        length has been removed - we now have only the limit on the total length of
252        the compiled pattern, which depends on the LINK_SIZE setting.
254    10. Fixed a bug in the documentation for get/copy named substring when
255        duplicate names are permitted. If none of the named substrings are set, the
256        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
257        empty string.
259    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
260        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
261        because the ] is interpreted as the first data character and the
262        terminating ] is not found. PCRE has been made compatible with Perl in this
263        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
264        cause memory overwriting.
266    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
267        string has been matched (to stop an infinite loop). It was not recognizing
268        a conditional subpattern that could match an empty string if that
269        subpattern was within another subpattern. For example, it looped when
270        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
271        condition was not nested. This bug has been fixed.
273    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
274        past the start of the subject in the presence of bytes with the top bit
275        set, for example "\x8aBCD".
277    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
278        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
280    14. Optimized (?!) to (*FAIL).
282    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
283        This restricts code points to be within the range 0 to 0x10FFFF, excluding
284        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
285        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
286        does: it's just the validity check that is more restrictive.
288    16. Inserted checks for integer overflows during escape sequence (backslash)
289        processing, and also fixed erroneous offset values for syntax errors during
290        backslash processing.
292    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
293        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
295    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
296        caused an overrun.
298    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
299        something other than just ASCII characters) inside a group that had an
300        unlimited repeat caused a loop at compile time (while checking to see
301        whether the group could match an empty string).
303    20. Debugging a pattern containing \p or \P could cause a crash. For example,
304        [\P{Any}] did so. (Error in the code for printing property names.)
306    21. An orphan \E inside a character class could cause a crash.
308    22. A repeated capturing bracket such as (A)? could cause a wild memory
309        reference during compilation.
311    23. There are several functions in pcre_compile() that scan along a compiled
312        expression for various reasons (e.g. to see if it's fixed length for look
313        behind). There were bugs in these functions when a repeated \p or \P was
314        present in the pattern. These operators have additional parameters compared
315        with \d, etc, and these were not being taken into account when moving along
316        the compiled data. Specifically:
318        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
319            length.
321        (b) An item such as \pL+ within a repeated group could cause crashes or
322            loops.
324        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
325            "reference to non-existent subpattern" error.
327        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
329    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
330        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
332    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
334    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
335        character were causing crashes (broken optimization).
337    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
338        \p or \P) caused a compile-time loop.
340    28. More problems have arisen in unanchored patterns when CRLF is a valid line
341        break. For example, the unstudied pattern [\r\n]A does not match the string
342        "\r\nA" because change 7.0/46 below moves the current point on by two
343        characters after failing to match at the start. However, the pattern \nA
344        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
345        the same is true. There doesn't seem any very clean way out of this, but
346        what I have chosen to do makes the common cases work: PCRE now takes note
347        of whether there can be an explicit match for \r or \n anywhere in the
348        pattern, and if so, 7.0/46 no longer applies. As part of this change,
349        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
350        pattern has explicit CR or LF references.
352    29. Added (*CR) etc for changing newline setting at start of pattern.
355    Version 7.2 19-Jun-07
356    ---------------------
358     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
359        which is apparently normally available under Windows.
361     2. Re-jig the pcregrep tests with different newline settings in an attempt
362        to make them independent of the local environment's newline setting.
364     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
366     4. Some of the "internals" tests were previously cut out when the link size
367        was not 2, because the output contained actual offsets. The recent new
368        "Z" feature of pcretest means that these can be cut out, making the tests
369        usable with all link sizes.
371     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
372        stack recursion. This gives a massive performance boost under BSD, but just
373        a small improvement under Linux. However, it saves one field in the frame
374        in all cases.
376     6. Added more features from the forthcoming Perl 5.10:
378        (a) (?-n) (where n is a string of digits) is a relative subroutine or
379            recursion call. It refers to the nth most recently opened parentheses.
381        (b) (?+n) is also a relative subroutine call; it refers to the nth next
382            to be opened parentheses.
384        (c) Conditions that refer to capturing parentheses can be specified
385            relatively, for example, (?(-2)... or (?(+3)...
387        (d) \K resets the start of the current match so that everything before
388            is not part of it.
390        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
392        (f) \g{name} is another synonym - part of Perl 5.10's unification of
393            reference syntax.
395        (g) (?| introduces a group in which the numbering of parentheses in each
396            alternative starts with the same number.
398        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
400     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
403     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
404        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
405        for detecting groups that can match an empty string.
407     9. A pattern with a very large number of alternatives (more than several
408        hundred) was running out of internal workspace during the pre-compile
409        phase, where pcre_compile() figures out how much memory will be needed. A
410        bit of new cunning has reduced the workspace needed for groups with
411        alternatives. The 1000-alternative test pattern now uses 12 bytes of
412        workspace instead of running out of the 4096 that are available.
414    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
416    11. Applied patch from Google to remove an optimization that didn't quite work.
417        The report of the bug said:
419          pcrecpp::RE("a*").FullMatch("aaa") matches, while
420          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
421          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
423    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
424        it matched the wrong number of bytes.
427    Version 7.1 24-Apr-07
428    ---------------------
430     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
431        that is more "standard", making use of automake and other Autotools. There
432        is some re-arrangement of the files and adjustment of comments consequent
433        on this.
435     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
436        for recursive directory scanning broke on some systems because the files
437        are not scanned in any specific order and on different systems the order
438        was different. A call to "sort" has been inserted into RunGrepTest for the
439        approprate test as a short-term fix. In the longer term there may be an
440        alternative.
442     3. I had an email from Eric Raymond about problems translating some of PCRE's
443        man pages to HTML (despite the fact that I distribute HTML pages, some
444        people do their own conversions for various reasons). The problems
445        concerned the use of low-level troff macros .br and .in. I have therefore
446        removed all such uses from the man pages (some were redundant, some could
447        be replaced by .nf/.fi pairs). The 132html script that I use to generate
448        HTML has been updated to handle .nf/.fi and to complain if it encounters
449        .br or .in.
451     4. Updated comments in configure.ac that get placed in config.h.in and also
452        arranged for config.h to be included in the distribution, with the name
453        config.h.generic, for the benefit of those who have to compile without
454        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
456     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
457        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
458        makevp.bat for the current PCRE, using the additional files
459        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
461     6. A Windows user reported a minor discrepancy with test 2, which turned out
462        to be caused by a trailing space on an input line that had got lost in his
463        copy. The trailing space was an accident, so I've just removed it.
465     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
466        that is needed.
468     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
469        as "const" (a) because they are and (b) because it helps the PHP
470        maintainers who have recently made a script to detect big data structures
471        in the php code that should be moved to the .rodata section. I remembered
472        to update Builducptable as well, so it won't revert if ucptable.h is ever
473        re-created.
475     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
476        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
477        order to be able to cut out the UTF-8 tables in the latter when UTF-8
478        support is not required. This saves 1.5-2K of code, which is important in
479        some applications.
481        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
482        so as not to refer to the tables, even though these functions will never be
483        called when UTF-8 support is disabled. Otherwise there are problems with a
484        shared library.
486    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
488        (a) It was defining its arguments as char * instead of void *.
490        (b) It was assuming that all moves were upwards in memory; this was true
491            a long time ago when I wrote it, but is no longer the case.
493        The emulated memove() is provided for those environments that have neither
494        memmove() nor bcopy(). I didn't think anyone used it these days, but that
495        is clearly not the case, as these two bugs were recently reported.
497    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
498        and Detrail to create the HTML documentation, the .txt form of the man
499        pages, and it removes trailing spaces from listed files. It also creates
500        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
501        case, it wraps all the #defines with #ifndefs. This script should be run
502        before "make dist".
504    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
505        with Unicode property support.
507        (a) For a maximizing quantifier, if the two different cases of the
508            character were of different lengths in their UTF-8 codings (there are
509            some cases like this - I found 11), and the matching function had to
510            back up over a mixture of the two cases, it incorrectly assumed they
511            were both the same length.
513        (b) When PCRE was configured to use the heap rather than the stack for
514            recursion during matching, it was not correctly preserving the data for
515            the other case of a UTF-8 character when checking ahead for a match
516            while processing a minimizing repeat. If the check also involved
517            matching a wide character, but failed, corruption could cause an
518            erroneous result when trying to check for a repeat of the original
519            character.
521    13. Some tidying changes to the testing mechanism:
523        (a) The RunTest script now detects the internal link size and whether there
524            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
525            values substituted by "configure". (The RunGrepTest script already did
526            this for UTF-8.) The configure.ac script no longer substitutes the
527            relevant variables.
529        (b) The debugging options /B and /D in pcretest show the compiled bytecode
530            with length and offset values. This means that the output is different
531            for different internal link sizes. Test 2 is skipped for link sizes
532            other than 2 because of this, bypassing the problem. Unfortunately,
533            there was also a test in test 3 (the locale tests) that used /B and
534            failed for link sizes other than 2. Rather than cut the whole test out,
535            I have added a new /Z option to pcretest that replaces the length and
536            offset values with spaces. This is now used to make test 3 independent
537            of link size. (Test 2 will be tidied up later.)
539    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
540        segmentation fault instead of returning the appropriate error message.
542    15. In multiline mode when the newline sequence was set to "any", the pattern
543        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
544        This doesn't seem right; it now treats the CRLF combination as the line
545        ending, and so does not match in that case. It's only a pattern such as ^$
546        that would hit this one: something like ^ABC$ would have failed after \r
547        and then tried again after \r\n.
549    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
550        in an attempt to make files that differ only in their line terminators
551        compare equal. This works on Linux.
553    17. Under certain error circumstances pcregrep might try to free random memory
554        as it exited. This is now fixed, thanks to valgrind.
556    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
557        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
558        was because its rules for how to advance for /g after matching an empty
559        string at the end of a line did not allow for this case. They now check for
560        it specially.
562    20. pcretest is supposed to handle patterns and data of any length, by
563        extending its buffers when necessary. It was getting this wrong when the
564        buffer for a data line had to be extended.
566    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
567        CRLF as a newline sequence.
569    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
570        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
571        I have nevertheless tidied it up.
573    23. Added some casts to kill warnings from HP-UX ia64 compiler.
575    24. Added a man page for pcre-config.
578    Version 7.0 19-Dec-06
579    ---------------------
581     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
582        moving to gcc 4.1.1.
584     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
585        sys/time.h, which is documented as needed for this function. It doesn't
586        seem to matter on Linux, but it showed up on some releases of OS X.
588     3. It seems that there are systems where bytes whose values are greater than
589        127 match isprint() in the "C" locale. The "C" locale should be the
590        default when a C program starts up. In most systems, only ASCII printing
591        characters match isprint(). This difference caused the output from pcretest
592        to vary, making some of the tests fail. I have changed pcretest so that:
594        (a) When it is outputting text in the compiled version of a pattern, bytes
595            other than 32-126 are always shown as hex escapes.
597        (b) When it is outputting text that is a matched part of a subject string,
598            it does the same, unless a different locale has been set for the match
599            (using the /L modifier). In this case, it uses isprint() to decide.
601     4. Fixed a major bug that caused incorrect computation of the amount of memory
602        required for a compiled pattern when options that changed within the
603        pattern affected the logic of the preliminary scan that determines the
604        length. The relevant options are -x, and -i in UTF-8 mode. The result was
605        that the computed length was too small. The symptoms of this bug were
606        either the PCRE error "internal error: code overflow" from pcre_compile(),
607        or a glibc crash with a message such as "pcretest: free(): invalid next
608        size (fast)". Examples of patterns that provoked this bug (shown in
609        pcretest format) are:
611          /(?-x: )/x
612          /(?x)(?-x: \s*#\s*)/
613          /((?i)[\x{c0}])/8
614          /(?i:[\x{c0}])/8
616        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
617        is now done differently.
619     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
620        wrapper classes; (b) implement a new function in the C++ scanner that is
621        more efficient than the old way of doing things because it avoids levels of
622        recursion in the regex matching; (c) add a paragraph to the documentation
623        for the FullMatch() function.
625     6. The escape sequence \n was being treated as whatever was defined as
626        "newline". Not only was this contrary to the documentation, which states
627        that \n is character 10 (hex 0A), but it also went horribly wrong when
628        "newline" was defined as CRLF. This has been fixed.
630     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
631        was being set to -1 for the "end of line" case (supposedly a value that no
632        character can have). Though this value is never used (the check for end of
633        line is "zero bytes in current character"), it caused compiler complaints.
634        I've changed it to 0xffffffff.
636     8. In pcre_version.c, the version string was being built by a sequence of
637        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
638        string (as it is for production releases) called a macro with an empty
639        argument. The C standard says the result of this is undefined. The gcc
640        compiler treats it as an empty string (which was what was wanted) but it is
641        reported that Visual C gives an error. The source has been hacked around to
642        avoid this problem.
644     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
645        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
646        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
647        of them did).
649    10. Originally, pcretest opened its input and output without "b"; then I was
650        told that "b" was needed in some environments, so it was added for release
651        5.0 to both the input and output. (It makes no difference on Unix-like
652        systems.) Later I was told that it is wrong for the input on Windows. I've
653        now abstracted the modes into two macros, to make it easier to fiddle with
654        them, and removed "b" from the input mode under Windows.
656    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
658    12. Added -help and --help to pcretest as an official way of being reminded
659        of the options.
661    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
662        and pcrecpp.cc because they annoy compilers at high warning levels.
664    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
666    15. Fixed an occurrence of == in configure.ac that should have been = (shell
667        scripts are not C programs :-) and which was not noticed because it works
668        on Linux.
670    16. pcretest is supposed to handle any length of pattern and data line (as one
671        line or as a continued sequence of lines) by extending its input buffer if
672        necessary. This feature was broken for very long pattern lines, leading to
673        a string of junk being passed to pcre_compile() if the pattern was longer
674        than about 50K.
676    17. I have done a major re-factoring of the way pcre_compile() computes the
677        amount of memory needed for a compiled pattern. Previously, there was code
678        that made a preliminary scan of the pattern in order to do this. That was
679        OK when PCRE was new, but as the facilities have expanded, it has become
680        harder and harder to keep it in step with the real compile phase, and there
681        have been a number of bugs (see for example, 4 above). I have now found a
682        cunning way of running the real compile function in a "fake" mode that
683        enables it to compute how much memory it would need, while actually only
684        ever using a few hundred bytes of working memory and without too many
685        tests of the mode. This should make future maintenance and development
686        easier. A side effect of this work is that the limit of 200 on the nesting
687        depth of parentheses has been removed (though this was never a serious
688        limitation, I suspect). However, there is a downside: pcre_compile() now
689        runs more slowly than before (30% or more, depending on the pattern). I
690        hope this isn't a big issue. There is no effect on runtime performance.
692    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
693        newline (only possible for the last line of a file) and it was a
694        pattern that set a locale (followed by /Lsomething), pcretest crashed.
696    19. Added additional timing features to pcretest. (1) The -tm option now times
697        matching only, not compiling. (2) Both -t and -tm can be followed, as a
698        separate command line item, by a number that specifies the number of
699        repeats to use when timing. The default is 50000; this gives better
700        precision, but takes uncomfortably long for very large patterns.
702    20. Extended pcre_study() to be more clever in cases where a branch of a
703        subpattern has no definite first character. For example, (a*|b*)[cd] would
704        previously give no result from pcre_study(). Now it recognizes that the
705        first character must be a, b, c, or d.
707    21. There was an incorrect error "recursive call could loop indefinitely" if
708        a subpattern (or the entire pattern) that was being tested for matching an
709        empty string contained only one non-empty item after a nested subpattern.
710        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
711        incorrectly, because the \d was being skipped in the check.
713    22. The pcretest program now has a new pattern option /B and a command line
714        option -b, which is equivalent to adding /B to every pattern. This causes
715        it to show the compiled bytecode, without the additional information that
716        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
717        is the same as /B/I).
719    23. A new optimization is now able automatically to treat some sequences such
720        as a*b as a*+b. More specifically, if something simple (such as a character
721        or a simple class like \d) has an unlimited quantifier, and is followed by
722        something that cannot possibly match the quantified thing, the quantifier
723        is automatically "possessified".
725    24. A recursive reference to a subpattern whose number was greater than 39
726        went wrong under certain circumstances in UTF-8 mode. This bug could also
727        have affected the operation of pcre_study().
729    25. Realized that a little bit of performance could be had by replacing
730        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
732    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
734    27. Possessive quantifiers such as a++ were previously implemented by turning
735        them into atomic groups such as ($>a+). Now they have their own opcodes,
736        which improves performance. This includes the automatically created ones
737        from 23 above.
739    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
740        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
741        the first matched character to be a colon. This applied both to named and
742        numbered groups.
744    29. The ucpinternal.h header file was missing its idempotency #ifdef.
746    30. I was sent a "project" file called libpcre.a.dev which I understand makes
747        building PCRE on Windows easier, so I have included it in the distribution.
749    31. There is now a check in pcretest against a ridiculously large number being
750        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
751        loop, the loop is abandoned.
753    32. Forward references to subpatterns in conditions such as (?(2)...) where
754        subpattern 2 is defined later cause pcre_compile() to search forwards in
755        the pattern for the relevant set of parentheses. This search went wrong
756        when there were unescaped parentheses in a character class, parentheses
757        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
759    33. "Subroutine" calls and backreferences were previously restricted to
760        referencing subpatterns earlier in the regex. This restriction has now
761        been removed.
763    34. Added a number of extra features that are going to be in Perl 5.10. On the
764        whole, these are just syntactic alternatives for features that PCRE had
765        previously implemented using the Python syntax or my own invention. The
766        other formats are all retained for compatibility.
768        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
769            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
770            also .NET compatible.
772        (b) A recursion or subroutine call to a named group can now be defined as
773            (?&name) as well as (?P>name).
775        (c) A backreference to a named group can now be defined as \k<name> or
776            \k'name' as well as (?P=name). The new forms, as well as being in Perl
777            5.10, are also .NET compatible.
779        (d) A conditional reference to a named group can now use the syntax
780            (?(<name>) or (?('name') as well as (?(name).
782        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
783            groups (named and numbered) that are never evaluated inline, but can be
784            called as "subroutines" from elsewhere. In effect, the DEFINE condition
785            is always false. There may be only one alternative in such a group.
787        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
788            as the simple (?(R). The condition is true only if the most recent
789            recursion is that of the given number or name. It does not search out
790            through the entire recursion stack.
792        (g) The escape \gN or \g{N} has been added, where N is a positive or
793            negative number, specifying an absolute or relative reference.
795    35. Tidied to get rid of some further signed/unsigned compiler warnings and
796        some "unreachable code" warnings.
798    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
799        things, this adds five new scripts.
801    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
802        There were also incompatibilities regarding the handling of \Q..\E inside
803        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
804        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
806    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
807        matches an empty string, and forcibly breaks the loop. There were bugs in
808        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
809        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
810        separate and independent bugs (that affected different cases) have been
811        fixed.
813    39. Refactored the code to abolish the use of different opcodes for small
814        capturing bracket numbers. This is a tidy that I avoided doing when I
815        removed the limit on the number of capturing brackets for 3.5 back in 2001.
816        The new approach is not only tidier, it makes it possible to reduce the
817        memory needed to fix the previous bug (38).
819    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
820        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
821        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
822        mode.
824    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
825        report.
827    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
828        copy construction and assignment in the C++ wrapper.
830    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
831        couple of bugs that could have given wrong results in the "--newline=crlf"
832        case.
834    44. Added a number of casts and did some reorganization of signed/unsigned int
835        variables following suggestions from Dair Grant. Also renamed the variable
836        "this" as "item" because it is a C++ keyword.
838    45. Arranged for dftables to add
840          #include "pcre_internal.h"
842        to pcre_chartables.c because without it, gcc 4.x may remove the array
843        definition from the final binary if PCRE is built into a static library and
844        dead code stripping is activated.
846    46. For an unanchored pattern, if a match attempt fails at the start of a
847        newline sequence, and the newline setting is CRLF or ANY, and the next two
848        characters are CRLF, advance by two characters instead of one.
851    Version 6.7 04-Jul-06
852    ---------------------
854     1. In order to handle tests when input lines are enormously long, pcretest has
855        been re-factored so that it automatically extends its buffers when
856        necessary. The code is crude, but this _is_ just a test program. The
857        default size has been increased from 32K to 50K.
859     2. The code in pcre_study() was using the value of the re argument before
860        testing it for NULL. (Of course, in any sensible call of the function, it
861        won't be NULL.)
863     3. The memmove() emulation function in pcre_internal.h, which is used on
864        systems that lack both memmove() and bcopy() - that is, hardly ever -
865        was missing a "static" storage class specifier.
867     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
868        containing an extended class (one that cannot be represented by a bitmap
869        because it contains high-valued characters or Unicode property items, e.g.
870        [\pZ]). Almost always one would set UTF-8 mode when processing such a
871        pattern, but PCRE should not loop if you do not (it no longer does).
872        [Detail: two cases were found: (a) a repeated subpattern containing an
873        extended class; (b) a recursive reference to a subpattern that followed a
874        previous extended class. It wasn't skipping over the extended class
875        correctly when UTF-8 mode was not set.]
877     5. A negated single-character class was not being recognized as fixed-length
878        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
879        compile error "lookbehind assertion is not fixed length".
881     6. The RunPerlTest auxiliary script was showing an unexpected difference
882        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
883        write a Perl script that can interpret lines of an input file either as
884        byte characters or as UTF-8, which is what "perltest" was being required to
885        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
886        can't do is switch easily at run time between having the "use utf8;" pragma
887        or not. In the end, I fudged it by using the RunPerlTest script to insert
888        "use utf8;" explicitly for the UTF-8 tests.
890     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
891        the end of the subject string, contrary to the documentation and to what
892        Perl does. This was true of both matching functions. Now it matches only at
893        the start of the subject and immediately after *internal* newlines.
895     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
896        a pointer to an int instead of a pointer to an unsigned long int. This
897        caused problems on 64-bit systems.
899     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
900        instance of the 'standard' template library not being so standard".
902    10. There was no check on the number of named subpatterns nor the maximum
903        length of a subpattern name. The product of these values is used to compute
904        the size of the memory block for a compiled pattern. By supplying a very
905        long subpattern name and a large number of named subpatterns, the size
906        computation could be caused to overflow. This is now prevented by limiting
907        the length of names to 32 characters, and the number of named subpatterns
908        to 10,000.
910    11. Subpatterns that are repeated with specific counts have to be replicated in
911        the compiled pattern. The size of memory for this was computed from the
912        length of the subpattern and the repeat count. The latter is limited to
913        65535, but there was no limit on the former, meaning that integer overflow
914        could in principle occur. The compiled length of a repeated subpattern is
915        now limited to 30,000 bytes in order to prevent this.
917    12. Added the optional facility to have named substrings with the same name.
919    13. Added the ability to use a named substring as a condition, using the
920        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
921        are numbers (not recommended). Forward references are permitted.
923    14. Added forward references in named backreferences (if you see what I mean).
925    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
926        pattern could run off the end of the subject. For example, the pattern
927        "(?s)(.{1,5})"8 did this with the subject "ab".
929    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
930        PCRE_CASELESS was set when matching characters that were quantified with ?
931        or *.
933    17. A character class other than a single negated character that had a minimum
934        but no maximum quantifier - for example [ab]{6,} - was not handled
935        correctly by pce_dfa_exec(). It would match only one character.
937    18. A valid (though odd) pattern that looked like a POSIX character
938        class but used an invalid character after [ (for example [[,abc,]]) caused
939        pcre_compile() to give the error "Failed: internal error: code overflow" or
940        in some cases to crash with a glibc free() error. This could even happen if
941        the pattern terminated after [[ but there just happened to be a sequence of
942        letters, a binary zero, and a closing ] in the memory that followed.
944    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
945        over the years. Originally (before any Unicode support), just the bottom 8
946        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
947        output from "man perlunicode" includes this:
949          The regular expression compiler produces polymorphic opcodes.  That
950          is, the pattern adapts to the data and automatically switches to
951          the Unicode character scheme when presented with Unicode data--or
952          instead uses a traditional byte scheme when presented with byte
953          data.
955        Sadly, a wide octal escape does not cause a switch, and in a string with
956        no other multibyte characters, these octal escapes are treated as before.
957        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
958        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
959        Unicode string.
961        I have not perpetrated such confusion in PCRE. Up till now, it took just
962        the bottom 8 bits, as in old Perl. I have now made octal escapes with
963        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
964        translate to the appropriate multibyte character.
966    29. Applied some refactoring to reduce the number of warnings from Microsoft
967        and Borland compilers. This has included removing the fudge introduced
968        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
969        a warning about an unused variable.
971    21. PCRE has not included VT (character 0x0b) in the set of whitespace
972        characters since release 4.0, because Perl (from release 5.004) does not.
973        [Or at least, is documented not to: some releases seem to be in conflict
974        with the documentation.] However, when a pattern was studied with
975        pcre_study() and all its branches started with \s, PCRE still included VT
976        as a possible starting character. Of course, this did no harm; it just
977        caused an unnecessary match attempt.
979    22. Removed a now-redundant internal flag bit that recorded the fact that case
980        dependency changed within the pattern. This was once needed for "required
981        byte" processing, but is no longer used. This recovers a now-scarce options
982        bit. Also moved the least significant internal flag bit to the most-
983        significant bit of the word, which was not previously used (hangover from
984        the days when it was an int rather than a uint) to free up another bit for
985        the future.
987    23. Added support for CRLF line endings as well as CR and LF. As well as the
988        default being selectable at build time, it can now be changed at runtime
989        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
990        specify that it is scanning data with non-default line endings.
992    24. Changed the definition of CXXLINK to make it agree with the definition of
993        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
995    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
996        recursions. This makes a big different to stack usage for some patterns.
998    26. If a subpattern containing a named recursion or subroutine reference such
999        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1000        the space required for the compiled pattern went wrong and gave too small a
1001        value. Depending on the environment, this could lead to "Failed: internal
1002        error: code overflow at offset 49" or "glibc detected double free or
1003        corruption" errors.
1005    27. Applied patches from Google (a) to support the new newline modes and (b) to
1006        advance over multibyte UTF-8 characters in GlobalReplace.
1008    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1009        difference for some implementation of PCRE in some Windows version.
1011    29. Added some extra testing facilities to pcretest:
1013        \q<number>   in a data line sets the "match limit" value
1014        \Q<number>   in a data line sets the "match recursion limt" value
1015        -S <number>  sets the stack size, where <number> is in megabytes
1017        The -S option isn't available for Windows.
1020    Version 6.6 06-Feb-06
1021    ---------------------
1023     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1024        in pcreposix.h. I have copied the definition from pcre.h.
1026     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1027        because pcre.h is no longer a built file.
1029     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1030        not normally included in the compiled code.
1033  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1034  ---------------------  ---------------------

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