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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.6 14-Jan-08
5    ---------------------
7    1.  A class with a very large number of characters with codepoints greater
8        than 255 (in UTF-8 mode, of course), caused a buffer overflow.
11    Version 7.5 10-Jan-08
12    ---------------------
14    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
15        values in parens when parsing an RE using the C++ wrapper."
17    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
18        Characters greater than 255 were excluded from the class instead of being
19        included.
21    3.  The same bug as (2) above applied to negated POSIX classes such as
22        [:^space:].
24    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
25        defined or documented. It seems to have been a typo for PCRE_STATIC, so
26        I have changed it.
28    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
29        first named subpattern) and a construct such as (?&a) would reference the
30        first named subpattern whose name started with "a" (in other words, the
31        length check was missing). Both these problems are fixed. "Subpattern name
32        expected" is now given for (?&) (a zero-length name), and this patch also
33        makes it give the same error for \k'' (previously it complained that that
34        was a reference to a non-existent subpattern).
36    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
37        this is right because (?- can be followed by option settings as well as by
38        digits. I have, however, made the messages clearer.
40    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
41        than the number used in the conditional) now cause a compile-time error.
42        This is actually not compatible with Perl, which accepts such patterns, but
43        treats the conditional as always being FALSE (as PCRE used to), but it
44        seems to me that giving a diagnostic is better.
46    8.  Change "alphameric" to the more common word "alphanumeric" in comments
47        and messages.
49    9.  Fix two occurrences of "backslash" in comments that should have been
50        "backspace".
52    10. Remove two redundant lines of code that can never be obeyed (their function
53        was moved elsewhere).
55    11. The program that makes PCRE's Unicode character property table had a bug
56        which caused it to generate incorrect table entries for sequences of
57        characters that have the same character type, but are in different scripts.
58        It amalgamated them into a single range, with the script of the first of
59        them. In other words, some characters were in the wrong script. There were
60        thirteen such cases, affecting characters in the following ranges:
62          U+002b0 - U+002c1
63          U+0060c - U+0060d
64          U+0061e - U+00612
65          U+0064b - U+0065e
66          U+0074d - U+0076d
67          U+01800 - U+01805
68          U+01d00 - U+01d77
69          U+01d9b - U+01dbf
70          U+0200b - U+0200f
71          U+030fc - U+030fe
72          U+03260 - U+0327f
73          U+0fb46 - U+0fbb1
74          U+10450 - U+1049d
76    12. The -o option (show only the matching part of a line) for pcregrep was not
77        compatible with GNU grep in that, if there was more than one match in a
78        line, it showed only the first of them. It now behaves in the same way as
79        GNU grep.
81    13. If the -o and -v options were combined for pcregrep, it printed a blank
82        line for every non-matching line. GNU grep prints nothing, and pcregrep now
83        does the same. The return code can be used to tell if there were any
84        non-matching lines.
86    14. Added --file-offsets and --line-offsets to pcregrep.
88    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
89        infinitely looping recursion. The bug was that positive lookaheads were not
90        being skipped when checking for a possible empty match (negative lookaheads
91        and both kinds of lookbehind were skipped).
93    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
94        inclusion of <windows.h> to before rather than after the definition of
95        INVALID_FILE_ATTRIBUTES (patch from David Byron).
97    17. Specifying a possessive quantifier with a specific limit for a Unicode
98        character property caused pcre_compile() to compile bad code, which led at
99        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
100        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
101        caused the error; without that there was no problem.
103    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
105    19. Added --enable-pcretest-libreadline.
107    20. In pcrecpp.cc, the variable 'count' was incremented twice in
108        RE::GlobalReplace(). As a result, the number of replacements returned was
109        double what it should be. I removed one of the increments, but Craig sent a
110        later patch that removed the other one (the right fix) and added unit tests
111        that check the return values (which was not done before).
113    21. Several CMake things:
115        (1) Arranged that, when cmake is used on Unix, the libraries end up with
116            the names libpcre and libpcreposix, not just pcre and pcreposix.
118        (2) The above change means that pcretest and pcregrep are now correctly
119            linked with the newly-built libraries, not previously installed ones.
123    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
124        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
125        UTF-8 newline character). The key issue is that the pattern starts .*;
126        this means that the match must be either at the beginning, or after a
127        newline. The bug was in the code for advancing after a failed match and
128        checking that the new position followed a newline. It was not taking
129        account of UTF-8 characters correctly.
131    23. PCRE was behaving differently from Perl in the way it recognized POSIX
132        character classes. PCRE was not treating the sequence [:...:] as a
133        character class unless the ... were all letters. Perl, however, seems to
134        allow any characters between [: and :], though of course it rejects as
135        unknown any "names" that contain non-letters, because all the known class
136        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
137        for example, whereas PCRE did not - it did not recognize a POSIX character
138        class. This seemed a bit dangerous, so the code has been changed to be
139        closer to Perl. The behaviour is not identical to Perl, because PCRE will
140        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
141        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
142        Perl does, and where it didn't before.
144    24. Rewrite so as to remove the single use of %n from pcregrep because in some
145        Windows environments %n is disabled by default.
148    Version 7.4 21-Sep-07
149    ---------------------
151    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
152        means that a class such as [\s] counted as "explicit reference to CR or
153        LF". That isn't really right - the whole point of the change was to try to
154        help when there was an actual mention of one of the two characters. So now
155        the change happens only if \r or \n (or a literal CR or LF) character is
156        encountered.
158    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
159        of both had grown to the point where there were only 3 bits left.
160        Fortunately, there was spare space in the data structure, and so I have
161        moved the internal flags into a new 16-bit field to free up more option
162        bits.
164    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
165        but did not set the internal JCHANGED flag - either of these is enough to
166        control the way the "get" function works - but the PCRE_INFO_JCHANGED
167        facility is supposed to tell if (?J) was ever used, so now (?J) at the
168        start sets both bits.
170    4.  Added options (at build time, compile time, exec time) to change \R from
171        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
173    5.  doc/pcresyntax.html was missing from the distribution.
175    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
176        compatibility, even though it is no longer used.
178    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
179        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
180        windows.h file is present (where different names are used). [This was
181        reversed later after testing - see 16 below.]
183    8.  Changed all #include <config.h> to #include "config.h". There were also
184        some further <pcre.h> cases that I changed to "pcre.h".
186    9.  When pcregrep was used with the --colour option, it missed the line ending
187        sequence off the lines that it output.
189    10. It was pointed out to me that arrays of string pointers cause lots of
190        relocations when a shared library is dynamically loaded. A technique of
191        using a single long string with a table of offsets can drastically reduce
192        these. I have refactored PCRE in four places to do this. The result is
193        dramatic:
195          Originally:                          290
196          After changing UCP table:            187
197          After changing error message table:   43
198          After changing table of "verbs"       36
199          After changing table of Posix names   22
201        Thanks to the folks working on Gregex for glib for this insight.
203    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
204        unicode-properties was also set.
206    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
208    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
209        checked only for CRLF.
211    14. Added casts to pcretest.c to avoid compiler warnings.
213    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
215    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
216        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
217        entirely. This removes changes made in 7 above.
219    17. The CMake files have been updated, and there is now more information about
220        building with CMake in the NON-UNIX-USE document.
223    Version 7.3 28-Aug-07
224    ---------------------
226     1. In the rejigging of the build system that eventually resulted in 7.1, the
227        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
228        brackets there is not right, since it causes compilers to look for an
229        installed pcre.h, not the version that is in the source that is being
230        compiled (which of course may be different). I have changed it back to:
232          #include "pcre.h"
234        I have a vague recollection that the change was concerned with compiling in
235        different directories, but in the new build system, that is taken care of
236        by the VPATH setting the Makefile.
238     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
239        when the subject happened to end in the byte 0x85 (e.g. if the last
240        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
241        characters but of course it shouldn't be taken as a newline when it is part
242        of another character. The bug was that, for an unlimited repeat of . in
243        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
244        characters when looking for a newline.
246     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
248     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
249        in debug output.
251     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
252        long printing in the pcrecpp unittest when running under MinGW.
254     6. ESC_K was left out of the EBCDIC table.
256     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
257        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
258        limit also applies to "virtual nesting" when a pattern is recursive, and in
259        this case 1000 isn't so big. I have been able to remove this limit at the
260        expense of backing off one optimization in certain circumstances. Normally,
261        when pcre_exec() would call its internal match() function recursively and
262        immediately return the result unconditionally, it uses a "tail recursion"
263        feature to save stack. However, when a subpattern that can match an empty
264        string has an unlimited repetition quantifier, it no longer makes this
265        optimization. That gives it a stack frame in which to save the data for
266        checking that an empty string has been matched. Previously this was taken
267        from the 1000-entry workspace that had been reserved. So now there is no
268        explicit limit, but more stack is used.
270     8. Applied Daniel's patches to solve problems with the import/export magic
271        syntax that is required for Windows, and which was going wrong for the
272        pcreposix and pcrecpp parts of the library. These were overlooked when this
273        problem was solved for the main library.
275     9. There were some crude static tests to avoid integer overflow when computing
276        the size of patterns that contain repeated groups with explicit upper
277        limits. As the maximum quantifier is 65535, the maximum group length was
278        set at 30,000 so that the product of these two numbers did not overflow a
279        32-bit integer. However, it turns out that people want to use groups that
280        are longer than 30,000 bytes (though not repeat them that many times).
281        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
282        made it possible to implement the integer overflow checks in a much more
283        dynamic way, which I have now done. The artificial limitation on group
284        length has been removed - we now have only the limit on the total length of
285        the compiled pattern, which depends on the LINK_SIZE setting.
287    10. Fixed a bug in the documentation for get/copy named substring when
288        duplicate names are permitted. If none of the named substrings are set, the
289        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
290        empty string.
292    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
293        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
294        because the ] is interpreted as the first data character and the
295        terminating ] is not found. PCRE has been made compatible with Perl in this
296        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
297        cause memory overwriting.
299    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
300        string has been matched (to stop an infinite loop). It was not recognizing
301        a conditional subpattern that could match an empty string if that
302        subpattern was within another subpattern. For example, it looped when
303        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
304        condition was not nested. This bug has been fixed.
306    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
307        past the start of the subject in the presence of bytes with the top bit
308        set, for example "\x8aBCD".
310    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
311        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
313    14. Optimized (?!) to (*FAIL).
315    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
316        This restricts code points to be within the range 0 to 0x10FFFF, excluding
317        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
318        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
319        does: it's just the validity check that is more restrictive.
321    16. Inserted checks for integer overflows during escape sequence (backslash)
322        processing, and also fixed erroneous offset values for syntax errors during
323        backslash processing.
325    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
326        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
328    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
329        caused an overrun.
331    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
332        something other than just ASCII characters) inside a group that had an
333        unlimited repeat caused a loop at compile time (while checking to see
334        whether the group could match an empty string).
336    20. Debugging a pattern containing \p or \P could cause a crash. For example,
337        [\P{Any}] did so. (Error in the code for printing property names.)
339    21. An orphan \E inside a character class could cause a crash.
341    22. A repeated capturing bracket such as (A)? could cause a wild memory
342        reference during compilation.
344    23. There are several functions in pcre_compile() that scan along a compiled
345        expression for various reasons (e.g. to see if it's fixed length for look
346        behind). There were bugs in these functions when a repeated \p or \P was
347        present in the pattern. These operators have additional parameters compared
348        with \d, etc, and these were not being taken into account when moving along
349        the compiled data. Specifically:
351        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
352            length.
354        (b) An item such as \pL+ within a repeated group could cause crashes or
355            loops.
357        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
358            "reference to non-existent subpattern" error.
360        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
362    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
363        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
365    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
367    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
368        character were causing crashes (broken optimization).
370    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
371        \p or \P) caused a compile-time loop.
373    28. More problems have arisen in unanchored patterns when CRLF is a valid line
374        break. For example, the unstudied pattern [\r\n]A does not match the string
375        "\r\nA" because change 7.0/46 below moves the current point on by two
376        characters after failing to match at the start. However, the pattern \nA
377        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
378        the same is true. There doesn't seem any very clean way out of this, but
379        what I have chosen to do makes the common cases work: PCRE now takes note
380        of whether there can be an explicit match for \r or \n anywhere in the
381        pattern, and if so, 7.0/46 no longer applies. As part of this change,
382        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
383        pattern has explicit CR or LF references.
385    29. Added (*CR) etc for changing newline setting at start of pattern.
388    Version 7.2 19-Jun-07
389    ---------------------
391     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
392        which is apparently normally available under Windows.
394     2. Re-jig the pcregrep tests with different newline settings in an attempt
395        to make them independent of the local environment's newline setting.
397     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
399     4. Some of the "internals" tests were previously cut out when the link size
400        was not 2, because the output contained actual offsets. The recent new
401        "Z" feature of pcretest means that these can be cut out, making the tests
402        usable with all link sizes.
404     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
405        stack recursion. This gives a massive performance boost under BSD, but just
406        a small improvement under Linux. However, it saves one field in the frame
407        in all cases.
409     6. Added more features from the forthcoming Perl 5.10:
411        (a) (?-n) (where n is a string of digits) is a relative subroutine or
412            recursion call. It refers to the nth most recently opened parentheses.
414        (b) (?+n) is also a relative subroutine call; it refers to the nth next
415            to be opened parentheses.
417        (c) Conditions that refer to capturing parentheses can be specified
418            relatively, for example, (?(-2)... or (?(+3)...
420        (d) \K resets the start of the current match so that everything before
421            is not part of it.
423        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
425        (f) \g{name} is another synonym - part of Perl 5.10's unification of
426            reference syntax.
428        (g) (?| introduces a group in which the numbering of parentheses in each
429            alternative starts with the same number.
431        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
433     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
436     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
437        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
438        for detecting groups that can match an empty string.
440     9. A pattern with a very large number of alternatives (more than several
441        hundred) was running out of internal workspace during the pre-compile
442        phase, where pcre_compile() figures out how much memory will be needed. A
443        bit of new cunning has reduced the workspace needed for groups with
444        alternatives. The 1000-alternative test pattern now uses 12 bytes of
445        workspace instead of running out of the 4096 that are available.
447    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
449    11. Applied patch from Google to remove an optimization that didn't quite work.
450        The report of the bug said:
452          pcrecpp::RE("a*").FullMatch("aaa") matches, while
453          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
454          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
456    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
457        it matched the wrong number of bytes.
460    Version 7.1 24-Apr-07
461    ---------------------
463     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
464        that is more "standard", making use of automake and other Autotools. There
465        is some re-arrangement of the files and adjustment of comments consequent
466        on this.
468     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
469        for recursive directory scanning broke on some systems because the files
470        are not scanned in any specific order and on different systems the order
471        was different. A call to "sort" has been inserted into RunGrepTest for the
472        approprate test as a short-term fix. In the longer term there may be an
473        alternative.
475     3. I had an email from Eric Raymond about problems translating some of PCRE's
476        man pages to HTML (despite the fact that I distribute HTML pages, some
477        people do their own conversions for various reasons). The problems
478        concerned the use of low-level troff macros .br and .in. I have therefore
479        removed all such uses from the man pages (some were redundant, some could
480        be replaced by .nf/.fi pairs). The 132html script that I use to generate
481        HTML has been updated to handle .nf/.fi and to complain if it encounters
482        .br or .in.
484     4. Updated comments in configure.ac that get placed in config.h.in and also
485        arranged for config.h to be included in the distribution, with the name
486        config.h.generic, for the benefit of those who have to compile without
487        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
489     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
490        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
491        makevp.bat for the current PCRE, using the additional files
492        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
494     6. A Windows user reported a minor discrepancy with test 2, which turned out
495        to be caused by a trailing space on an input line that had got lost in his
496        copy. The trailing space was an accident, so I've just removed it.
498     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
499        that is needed.
501     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
502        as "const" (a) because they are and (b) because it helps the PHP
503        maintainers who have recently made a script to detect big data structures
504        in the php code that should be moved to the .rodata section. I remembered
505        to update Builducptable as well, so it won't revert if ucptable.h is ever
506        re-created.
508     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
509        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
510        order to be able to cut out the UTF-8 tables in the latter when UTF-8
511        support is not required. This saves 1.5-2K of code, which is important in
512        some applications.
514        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
515        so as not to refer to the tables, even though these functions will never be
516        called when UTF-8 support is disabled. Otherwise there are problems with a
517        shared library.
519    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
521        (a) It was defining its arguments as char * instead of void *.
523        (b) It was assuming that all moves were upwards in memory; this was true
524            a long time ago when I wrote it, but is no longer the case.
526        The emulated memove() is provided for those environments that have neither
527        memmove() nor bcopy(). I didn't think anyone used it these days, but that
528        is clearly not the case, as these two bugs were recently reported.
530    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
531        and Detrail to create the HTML documentation, the .txt form of the man
532        pages, and it removes trailing spaces from listed files. It also creates
533        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
534        case, it wraps all the #defines with #ifndefs. This script should be run
535        before "make dist".
537    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
538        with Unicode property support.
540        (a) For a maximizing quantifier, if the two different cases of the
541            character were of different lengths in their UTF-8 codings (there are
542            some cases like this - I found 11), and the matching function had to
543            back up over a mixture of the two cases, it incorrectly assumed they
544            were both the same length.
546        (b) When PCRE was configured to use the heap rather than the stack for
547            recursion during matching, it was not correctly preserving the data for
548            the other case of a UTF-8 character when checking ahead for a match
549            while processing a minimizing repeat. If the check also involved
550            matching a wide character, but failed, corruption could cause an
551            erroneous result when trying to check for a repeat of the original
552            character.
554    13. Some tidying changes to the testing mechanism:
556        (a) The RunTest script now detects the internal link size and whether there
557            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
558            values substituted by "configure". (The RunGrepTest script already did
559            this for UTF-8.) The configure.ac script no longer substitutes the
560            relevant variables.
562        (b) The debugging options /B and /D in pcretest show the compiled bytecode
563            with length and offset values. This means that the output is different
564            for different internal link sizes. Test 2 is skipped for link sizes
565            other than 2 because of this, bypassing the problem. Unfortunately,
566            there was also a test in test 3 (the locale tests) that used /B and
567            failed for link sizes other than 2. Rather than cut the whole test out,
568            I have added a new /Z option to pcretest that replaces the length and
569            offset values with spaces. This is now used to make test 3 independent
570            of link size. (Test 2 will be tidied up later.)
572    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
573        segmentation fault instead of returning the appropriate error message.
575    15. In multiline mode when the newline sequence was set to "any", the pattern
576        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
577        This doesn't seem right; it now treats the CRLF combination as the line
578        ending, and so does not match in that case. It's only a pattern such as ^$
579        that would hit this one: something like ^ABC$ would have failed after \r
580        and then tried again after \r\n.
582    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
583        in an attempt to make files that differ only in their line terminators
584        compare equal. This works on Linux.
586    17. Under certain error circumstances pcregrep might try to free random memory
587        as it exited. This is now fixed, thanks to valgrind.
589    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
590        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
591        was because its rules for how to advance for /g after matching an empty
592        string at the end of a line did not allow for this case. They now check for
593        it specially.
595    20. pcretest is supposed to handle patterns and data of any length, by
596        extending its buffers when necessary. It was getting this wrong when the
597        buffer for a data line had to be extended.
599    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
600        CRLF as a newline sequence.
602    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
603        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
604        I have nevertheless tidied it up.
606    23. Added some casts to kill warnings from HP-UX ia64 compiler.
608    24. Added a man page for pcre-config.
611    Version 7.0 19-Dec-06
612    ---------------------
614     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
615        moving to gcc 4.1.1.
617     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
618        sys/time.h, which is documented as needed for this function. It doesn't
619        seem to matter on Linux, but it showed up on some releases of OS X.
621     3. It seems that there are systems where bytes whose values are greater than
622        127 match isprint() in the "C" locale. The "C" locale should be the
623        default when a C program starts up. In most systems, only ASCII printing
624        characters match isprint(). This difference caused the output from pcretest
625        to vary, making some of the tests fail. I have changed pcretest so that:
627        (a) When it is outputting text in the compiled version of a pattern, bytes
628            other than 32-126 are always shown as hex escapes.
630        (b) When it is outputting text that is a matched part of a subject string,
631            it does the same, unless a different locale has been set for the match
632            (using the /L modifier). In this case, it uses isprint() to decide.
634     4. Fixed a major bug that caused incorrect computation of the amount of memory
635        required for a compiled pattern when options that changed within the
636        pattern affected the logic of the preliminary scan that determines the
637        length. The relevant options are -x, and -i in UTF-8 mode. The result was
638        that the computed length was too small. The symptoms of this bug were
639        either the PCRE error "internal error: code overflow" from pcre_compile(),
640        or a glibc crash with a message such as "pcretest: free(): invalid next
641        size (fast)". Examples of patterns that provoked this bug (shown in
642        pcretest format) are:
644          /(?-x: )/x
645          /(?x)(?-x: \s*#\s*)/
646          /((?i)[\x{c0}])/8
647          /(?i:[\x{c0}])/8
649        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
650        is now done differently.
652     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
653        wrapper classes; (b) implement a new function in the C++ scanner that is
654        more efficient than the old way of doing things because it avoids levels of
655        recursion in the regex matching; (c) add a paragraph to the documentation
656        for the FullMatch() function.
658     6. The escape sequence \n was being treated as whatever was defined as
659        "newline". Not only was this contrary to the documentation, which states
660        that \n is character 10 (hex 0A), but it also went horribly wrong when
661        "newline" was defined as CRLF. This has been fixed.
663     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
664        was being set to -1 for the "end of line" case (supposedly a value that no
665        character can have). Though this value is never used (the check for end of
666        line is "zero bytes in current character"), it caused compiler complaints.
667        I've changed it to 0xffffffff.
669     8. In pcre_version.c, the version string was being built by a sequence of
670        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
671        string (as it is for production releases) called a macro with an empty
672        argument. The C standard says the result of this is undefined. The gcc
673        compiler treats it as an empty string (which was what was wanted) but it is
674        reported that Visual C gives an error. The source has been hacked around to
675        avoid this problem.
677     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
678        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
679        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
680        of them did).
682    10. Originally, pcretest opened its input and output without "b"; then I was
683        told that "b" was needed in some environments, so it was added for release
684        5.0 to both the input and output. (It makes no difference on Unix-like
685        systems.) Later I was told that it is wrong for the input on Windows. I've
686        now abstracted the modes into two macros, to make it easier to fiddle with
687        them, and removed "b" from the input mode under Windows.
689    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
691    12. Added -help and --help to pcretest as an official way of being reminded
692        of the options.
694    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
695        and pcrecpp.cc because they annoy compilers at high warning levels.
697    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
699    15. Fixed an occurrence of == in configure.ac that should have been = (shell
700        scripts are not C programs :-) and which was not noticed because it works
701        on Linux.
703    16. pcretest is supposed to handle any length of pattern and data line (as one
704        line or as a continued sequence of lines) by extending its input buffer if
705        necessary. This feature was broken for very long pattern lines, leading to
706        a string of junk being passed to pcre_compile() if the pattern was longer
707        than about 50K.
709    17. I have done a major re-factoring of the way pcre_compile() computes the
710        amount of memory needed for a compiled pattern. Previously, there was code
711        that made a preliminary scan of the pattern in order to do this. That was
712        OK when PCRE was new, but as the facilities have expanded, it has become
713        harder and harder to keep it in step with the real compile phase, and there
714        have been a number of bugs (see for example, 4 above). I have now found a
715        cunning way of running the real compile function in a "fake" mode that
716        enables it to compute how much memory it would need, while actually only
717        ever using a few hundred bytes of working memory and without too many
718        tests of the mode. This should make future maintenance and development
719        easier. A side effect of this work is that the limit of 200 on the nesting
720        depth of parentheses has been removed (though this was never a serious
721        limitation, I suspect). However, there is a downside: pcre_compile() now
722        runs more slowly than before (30% or more, depending on the pattern). I
723        hope this isn't a big issue. There is no effect on runtime performance.
725    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
726        newline (only possible for the last line of a file) and it was a
727        pattern that set a locale (followed by /Lsomething), pcretest crashed.
729    19. Added additional timing features to pcretest. (1) The -tm option now times
730        matching only, not compiling. (2) Both -t and -tm can be followed, as a
731        separate command line item, by a number that specifies the number of
732        repeats to use when timing. The default is 50000; this gives better
733        precision, but takes uncomfortably long for very large patterns.
735    20. Extended pcre_study() to be more clever in cases where a branch of a
736        subpattern has no definite first character. For example, (a*|b*)[cd] would
737        previously give no result from pcre_study(). Now it recognizes that the
738        first character must be a, b, c, or d.
740    21. There was an incorrect error "recursive call could loop indefinitely" if
741        a subpattern (or the entire pattern) that was being tested for matching an
742        empty string contained only one non-empty item after a nested subpattern.
743        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
744        incorrectly, because the \d was being skipped in the check.
746    22. The pcretest program now has a new pattern option /B and a command line
747        option -b, which is equivalent to adding /B to every pattern. This causes
748        it to show the compiled bytecode, without the additional information that
749        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
750        is the same as /B/I).
752    23. A new optimization is now able automatically to treat some sequences such
753        as a*b as a*+b. More specifically, if something simple (such as a character
754        or a simple class like \d) has an unlimited quantifier, and is followed by
755        something that cannot possibly match the quantified thing, the quantifier
756        is automatically "possessified".
758    24. A recursive reference to a subpattern whose number was greater than 39
759        went wrong under certain circumstances in UTF-8 mode. This bug could also
760        have affected the operation of pcre_study().
762    25. Realized that a little bit of performance could be had by replacing
763        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
765    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
767    27. Possessive quantifiers such as a++ were previously implemented by turning
768        them into atomic groups such as ($>a+). Now they have their own opcodes,
769        which improves performance. This includes the automatically created ones
770        from 23 above.
772    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
773        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
774        the first matched character to be a colon. This applied both to named and
775        numbered groups.
777    29. The ucpinternal.h header file was missing its idempotency #ifdef.
779    30. I was sent a "project" file called libpcre.a.dev which I understand makes
780        building PCRE on Windows easier, so I have included it in the distribution.
782    31. There is now a check in pcretest against a ridiculously large number being
783        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
784        loop, the loop is abandoned.
786    32. Forward references to subpatterns in conditions such as (?(2)...) where
787        subpattern 2 is defined later cause pcre_compile() to search forwards in
788        the pattern for the relevant set of parentheses. This search went wrong
789        when there were unescaped parentheses in a character class, parentheses
790        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
792    33. "Subroutine" calls and backreferences were previously restricted to
793        referencing subpatterns earlier in the regex. This restriction has now
794        been removed.
796    34. Added a number of extra features that are going to be in Perl 5.10. On the
797        whole, these are just syntactic alternatives for features that PCRE had
798        previously implemented using the Python syntax or my own invention. The
799        other formats are all retained for compatibility.
801        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
802            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
803            also .NET compatible.
805        (b) A recursion or subroutine call to a named group can now be defined as
806            (?&name) as well as (?P>name).
808        (c) A backreference to a named group can now be defined as \k<name> or
809            \k'name' as well as (?P=name). The new forms, as well as being in Perl
810            5.10, are also .NET compatible.
812        (d) A conditional reference to a named group can now use the syntax
813            (?(<name>) or (?('name') as well as (?(name).
815        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
816            groups (named and numbered) that are never evaluated inline, but can be
817            called as "subroutines" from elsewhere. In effect, the DEFINE condition
818            is always false. There may be only one alternative in such a group.
820        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
821            as the simple (?(R). The condition is true only if the most recent
822            recursion is that of the given number or name. It does not search out
823            through the entire recursion stack.
825        (g) The escape \gN or \g{N} has been added, where N is a positive or
826            negative number, specifying an absolute or relative reference.
828    35. Tidied to get rid of some further signed/unsigned compiler warnings and
829        some "unreachable code" warnings.
831    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
832        things, this adds five new scripts.
834    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
835        There were also incompatibilities regarding the handling of \Q..\E inside
836        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
837        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
839    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
840        matches an empty string, and forcibly breaks the loop. There were bugs in
841        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
842        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
843        separate and independent bugs (that affected different cases) have been
844        fixed.
846    39. Refactored the code to abolish the use of different opcodes for small
847        capturing bracket numbers. This is a tidy that I avoided doing when I
848        removed the limit on the number of capturing brackets for 3.5 back in 2001.
849        The new approach is not only tidier, it makes it possible to reduce the
850        memory needed to fix the previous bug (38).
852    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
853        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
854        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
855        mode.
857    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
858        report.
860    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
861        copy construction and assignment in the C++ wrapper.
863    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
864        couple of bugs that could have given wrong results in the "--newline=crlf"
865        case.
867    44. Added a number of casts and did some reorganization of signed/unsigned int
868        variables following suggestions from Dair Grant. Also renamed the variable
869        "this" as "item" because it is a C++ keyword.
871    45. Arranged for dftables to add
873          #include "pcre_internal.h"
875        to pcre_chartables.c because without it, gcc 4.x may remove the array
876        definition from the final binary if PCRE is built into a static library and
877        dead code stripping is activated.
879    46. For an unanchored pattern, if a match attempt fails at the start of a
880        newline sequence, and the newline setting is CRLF or ANY, and the next two
881        characters are CRLF, advance by two characters instead of one.
884    Version 6.7 04-Jul-06
885    ---------------------
887     1. In order to handle tests when input lines are enormously long, pcretest has
888        been re-factored so that it automatically extends its buffers when
889        necessary. The code is crude, but this _is_ just a test program. The
890        default size has been increased from 32K to 50K.
892     2. The code in pcre_study() was using the value of the re argument before
893        testing it for NULL. (Of course, in any sensible call of the function, it
894        won't be NULL.)
896     3. The memmove() emulation function in pcre_internal.h, which is used on
897        systems that lack both memmove() and bcopy() - that is, hardly ever -
898        was missing a "static" storage class specifier.
900     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
901        containing an extended class (one that cannot be represented by a bitmap
902        because it contains high-valued characters or Unicode property items, e.g.
903        [\pZ]). Almost always one would set UTF-8 mode when processing such a
904        pattern, but PCRE should not loop if you do not (it no longer does).
905        [Detail: two cases were found: (a) a repeated subpattern containing an
906        extended class; (b) a recursive reference to a subpattern that followed a
907        previous extended class. It wasn't skipping over the extended class
908        correctly when UTF-8 mode was not set.]
910     5. A negated single-character class was not being recognized as fixed-length
911        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
912        compile error "lookbehind assertion is not fixed length".
914     6. The RunPerlTest auxiliary script was showing an unexpected difference
915        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
916        write a Perl script that can interpret lines of an input file either as
917        byte characters or as UTF-8, which is what "perltest" was being required to
918        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
919        can't do is switch easily at run time between having the "use utf8;" pragma
920        or not. In the end, I fudged it by using the RunPerlTest script to insert
921        "use utf8;" explicitly for the UTF-8 tests.
923     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
924        the end of the subject string, contrary to the documentation and to what
925        Perl does. This was true of both matching functions. Now it matches only at
926        the start of the subject and immediately after *internal* newlines.
928     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
929        a pointer to an int instead of a pointer to an unsigned long int. This
930        caused problems on 64-bit systems.
932     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
933        instance of the 'standard' template library not being so standard".
935    10. There was no check on the number of named subpatterns nor the maximum
936        length of a subpattern name. The product of these values is used to compute
937        the size of the memory block for a compiled pattern. By supplying a very
938        long subpattern name and a large number of named subpatterns, the size
939        computation could be caused to overflow. This is now prevented by limiting
940        the length of names to 32 characters, and the number of named subpatterns
941        to 10,000.
943    11. Subpatterns that are repeated with specific counts have to be replicated in
944        the compiled pattern. The size of memory for this was computed from the
945        length of the subpattern and the repeat count. The latter is limited to
946        65535, but there was no limit on the former, meaning that integer overflow
947        could in principle occur. The compiled length of a repeated subpattern is
948        now limited to 30,000 bytes in order to prevent this.
950    12. Added the optional facility to have named substrings with the same name.
952    13. Added the ability to use a named substring as a condition, using the
953        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
954        are numbers (not recommended). Forward references are permitted.
956    14. Added forward references in named backreferences (if you see what I mean).
958    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
959        pattern could run off the end of the subject. For example, the pattern
960        "(?s)(.{1,5})"8 did this with the subject "ab".
962    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
963        PCRE_CASELESS was set when matching characters that were quantified with ?
964        or *.
966    17. A character class other than a single negated character that had a minimum
967        but no maximum quantifier - for example [ab]{6,} - was not handled
968        correctly by pce_dfa_exec(). It would match only one character.
970    18. A valid (though odd) pattern that looked like a POSIX character
971        class but used an invalid character after [ (for example [[,abc,]]) caused
972        pcre_compile() to give the error "Failed: internal error: code overflow" or
973        in some cases to crash with a glibc free() error. This could even happen if
974        the pattern terminated after [[ but there just happened to be a sequence of
975        letters, a binary zero, and a closing ] in the memory that followed.
977    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
978        over the years. Originally (before any Unicode support), just the bottom 8
979        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
980        output from "man perlunicode" includes this:
982          The regular expression compiler produces polymorphic opcodes.  That
983          is, the pattern adapts to the data and automatically switches to
984          the Unicode character scheme when presented with Unicode data--or
985          instead uses a traditional byte scheme when presented with byte
986          data.
988        Sadly, a wide octal escape does not cause a switch, and in a string with
989        no other multibyte characters, these octal escapes are treated as before.
990        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
991        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
992        Unicode string.
994        I have not perpetrated such confusion in PCRE. Up till now, it took just
995        the bottom 8 bits, as in old Perl. I have now made octal escapes with
996        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
997        translate to the appropriate multibyte character.
999    29. Applied some refactoring to reduce the number of warnings from Microsoft
1000        and Borland compilers. This has included removing the fudge introduced
1001        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1002        a warning about an unused variable.
1004    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1005        characters since release 4.0, because Perl (from release 5.004) does not.
1006        [Or at least, is documented not to: some releases seem to be in conflict
1007        with the documentation.] However, when a pattern was studied with
1008        pcre_study() and all its branches started with \s, PCRE still included VT
1009        as a possible starting character. Of course, this did no harm; it just
1010        caused an unnecessary match attempt.
1012    22. Removed a now-redundant internal flag bit that recorded the fact that case
1013        dependency changed within the pattern. This was once needed for "required
1014        byte" processing, but is no longer used. This recovers a now-scarce options
1015        bit. Also moved the least significant internal flag bit to the most-
1016        significant bit of the word, which was not previously used (hangover from
1017        the days when it was an int rather than a uint) to free up another bit for
1018        the future.
1020    23. Added support for CRLF line endings as well as CR and LF. As well as the
1021        default being selectable at build time, it can now be changed at runtime
1022        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1023        specify that it is scanning data with non-default line endings.
1025    24. Changed the definition of CXXLINK to make it agree with the definition of
1026        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1028    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1029        recursions. This makes a big different to stack usage for some patterns.
1031    26. If a subpattern containing a named recursion or subroutine reference such
1032        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1033        the space required for the compiled pattern went wrong and gave too small a
1034        value. Depending on the environment, this could lead to "Failed: internal
1035        error: code overflow at offset 49" or "glibc detected double free or
1036        corruption" errors.
1038    27. Applied patches from Google (a) to support the new newline modes and (b) to
1039        advance over multibyte UTF-8 characters in GlobalReplace.
1041    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1042        difference for some implementation of PCRE in some Windows version.
1044    29. Added some extra testing facilities to pcretest:
1046        \q<number>   in a data line sets the "match limit" value
1047        \Q<number>   in a data line sets the "match recursion limt" value
1048        -S <number>  sets the stack size, where <number> is in megabytes
1050        The -S option isn't available for Windows.
1053    Version 6.6 06-Feb-06
1054    ---------------------
1056     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1057        in pcreposix.h. I have copied the definition from pcre.h.
1059     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1060        because pcre.h is no longer a built file.
1062     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1063        not normally included in the compiled code.
1066  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1067  ---------------------  ---------------------

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