ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 69 by nigel, Sat Feb 24 21:40:18 2007 UTC revision 226 by ph10, Tue Aug 21 11:46:08 2007 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.3 20-Aug-07
5    ---------------------
7     1. In the rejigging of the build system that eventually resulted in 7.1, the
8        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
13          #include "pcre.h"
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
35     6. ESC_K was left out of the EBCDIC table.
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
94    14. Optimized (?!) to (*FAIL).
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
120    21. An orphan \E inside a character class could cause a crash.
122    22. A repeated capturing bracket such as (A)? could cause a wild memory
123        reference during compilation.
125    23. There are several functions in pcre_compile() that scan along a compiled
126        expression for various reasons (e.g. to see if it's fixed length for look
127        behind). There were bugs in these functions when a repeated \p or \P was
128        present in the pattern. These operators have additional parameters compared
129        with \d, etc, and these were not being taken into account when moving along
130        the compiled data. Specifically:
132        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
133            length.
135        (b) An item such as \pL+ within a repeated group could cause crashes or
136            loops.
138        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
139            "reference to non-existent subpattern" error.
141        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
143    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
144        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
146    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
148    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
149        character were causing crashes (broken optimization).
151    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
152        \p or \P) caused a compile-time loop.
154    28. More problems have arisen in unanchored patterns when CRLF is a valid line
155        break. For example, the unstudied pattern [\r\n]A does not match the string
156        "\r\nA" because change 7.0/46 below moves the current point on by two
157        characters after failing to match at the start. However, the pattern \nA
158        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
159        the same is true. There doesn't seem any very clean way out of this, but
160        what I have chosen to do makes the common cases work: PCRE now takes note
161        of whether there can be an explicit match for \r or \n anywhere in the
162        pattern, and if so, 7.0/46 no longer applies. As part of this change,
163        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
164        pattern has explicit CR or LF references.
167    Version 7.2 19-Jun-07
168    ---------------------
170     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
171        which is apparently normally available under Windows.
173     2. Re-jig the pcregrep tests with different newline settings in an attempt
174        to make them independent of the local environment's newline setting.
176     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
178     4. Some of the "internals" tests were previously cut out when the link size
179        was not 2, because the output contained actual offsets. The recent new
180        "Z" feature of pcretest means that these can be cut out, making the tests
181        usable with all link sizes.
183     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
184        stack recursion. This gives a massive performance boost under BSD, but just
185        a small improvement under Linux. However, it saves one field in the frame
186        in all cases.
188     6. Added more features from the forthcoming Perl 5.10:
190        (a) (?-n) (where n is a string of digits) is a relative subroutine or
191            recursion call. It refers to the nth most recently opened parentheses.
193        (b) (?+n) is also a relative subroutine call; it refers to the nth next
194            to be opened parentheses.
196        (c) Conditions that refer to capturing parentheses can be specified
197            relatively, for example, (?(-2)... or (?(+3)...
199        (d) \K resets the start of the current match so that everything before
200            is not part of it.
202        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
204        (f) \g{name} is another synonym - part of Perl 5.10's unification of
205            reference syntax.
207        (g) (?| introduces a group in which the numbering of parentheses in each
208            alternative starts with the same number.
210        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
212     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
215     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
216        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
217        for detecting groups that can match an empty string.
219     9. A pattern with a very large number of alternatives (more than several
220        hundred) was running out of internal workspace during the pre-compile
221        phase, where pcre_compile() figures out how much memory will be needed. A
222        bit of new cunning has reduced the workspace needed for groups with
223        alternatives. The 1000-alternative test pattern now uses 12 bytes of
224        workspace instead of running out of the 4096 that are available.
226    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
228    11. Applied patch from Google to remove an optimization that didn't quite work.
229        The report of the bug said:
231          pcrecpp::RE("a*").FullMatch("aaa") matches, while
232          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
233          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
235    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
236        it matched the wrong number of bytes.
239    Version 7.1 24-Apr-07
240    ---------------------
242     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
243        that is more "standard", making use of automake and other Autotools. There
244        is some re-arrangement of the files and adjustment of comments consequent
245        on this.
247     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
248        for recursive directory scanning broke on some systems because the files
249        are not scanned in any specific order and on different systems the order
250        was different. A call to "sort" has been inserted into RunGrepTest for the
251        approprate test as a short-term fix. In the longer term there may be an
252        alternative.
254     3. I had an email from Eric Raymond about problems translating some of PCRE's
255        man pages to HTML (despite the fact that I distribute HTML pages, some
256        people do their own conversions for various reasons). The problems
257        concerned the use of low-level troff macros .br and .in. I have therefore
258        removed all such uses from the man pages (some were redundant, some could
259        be replaced by .nf/.fi pairs). The 132html script that I use to generate
260        HTML has been updated to handle .nf/.fi and to complain if it encounters
261        .br or .in.
263     4. Updated comments in configure.ac that get placed in config.h.in and also
264        arranged for config.h to be included in the distribution, with the name
265        config.h.generic, for the benefit of those who have to compile without
266        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
268     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
269        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
270        makevp.bat for the current PCRE, using the additional files
271        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
273     6. A Windows user reported a minor discrepancy with test 2, which turned out
274        to be caused by a trailing space on an input line that had got lost in his
275        copy. The trailing space was an accident, so I've just removed it.
277     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
278        that is needed.
280     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
281        as "const" (a) because they are and (b) because it helps the PHP
282        maintainers who have recently made a script to detect big data structures
283        in the php code that should be moved to the .rodata section. I remembered
284        to update Builducptable as well, so it won't revert if ucptable.h is ever
285        re-created.
287     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
288        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
289        order to be able to cut out the UTF-8 tables in the latter when UTF-8
290        support is not required. This saves 1.5-2K of code, which is important in
291        some applications.
293        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
294        so as not to refer to the tables, even though these functions will never be
295        called when UTF-8 support is disabled. Otherwise there are problems with a
296        shared library.
298    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
300        (a) It was defining its arguments as char * instead of void *.
302        (b) It was assuming that all moves were upwards in memory; this was true
303            a long time ago when I wrote it, but is no longer the case.
305        The emulated memove() is provided for those environments that have neither
306        memmove() nor bcopy(). I didn't think anyone used it these days, but that
307        is clearly not the case, as these two bugs were recently reported.
309    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
310        and Detrail to create the HTML documentation, the .txt form of the man
311        pages, and it removes trailing spaces from listed files. It also creates
312        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
313        case, it wraps all the #defines with #ifndefs. This script should be run
314        before "make dist".
316    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
317        with Unicode property support.
319        (a) For a maximizing quantifier, if the two different cases of the
320            character were of different lengths in their UTF-8 codings (there are
321            some cases like this - I found 11), and the matching function had to
322            back up over a mixture of the two cases, it incorrectly assumed they
323            were both the same length.
325        (b) When PCRE was configured to use the heap rather than the stack for
326            recursion during matching, it was not correctly preserving the data for
327            the other case of a UTF-8 character when checking ahead for a match
328            while processing a minimizing repeat. If the check also involved
329            matching a wide character, but failed, corruption could cause an
330            erroneous result when trying to check for a repeat of the original
331            character.
333    13. Some tidying changes to the testing mechanism:
335        (a) The RunTest script now detects the internal link size and whether there
336            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
337            values substituted by "configure". (The RunGrepTest script already did
338            this for UTF-8.) The configure.ac script no longer substitutes the
339            relevant variables.
341        (b) The debugging options /B and /D in pcretest show the compiled bytecode
342            with length and offset values. This means that the output is different
343            for different internal link sizes. Test 2 is skipped for link sizes
344            other than 2 because of this, bypassing the problem. Unfortunately,
345            there was also a test in test 3 (the locale tests) that used /B and
346            failed for link sizes other than 2. Rather than cut the whole test out,
347            I have added a new /Z option to pcretest that replaces the length and
348            offset values with spaces. This is now used to make test 3 independent
349            of link size. (Test 2 will be tidied up later.)
351    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
352        segmentation fault instead of returning the appropriate error message.
354    15. In multiline mode when the newline sequence was set to "any", the pattern
355        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
356        This doesn't seem right; it now treats the CRLF combination as the line
357        ending, and so does not match in that case. It's only a pattern such as ^$
358        that would hit this one: something like ^ABC$ would have failed after \r
359        and then tried again after \r\n.
361    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
362        in an attempt to make files that differ only in their line terminators
363        compare equal. This works on Linux.
365    17. Under certain error circumstances pcregrep might try to free random memory
366        as it exited. This is now fixed, thanks to valgrind.
368    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
369        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
370        was because its rules for how to advance for /g after matching an empty
371        string at the end of a line did not allow for this case. They now check for
372        it specially.
374    20. pcretest is supposed to handle patterns and data of any length, by
375        extending its buffers when necessary. It was getting this wrong when the
376        buffer for a data line had to be extended.
378    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
379        CRLF as a newline sequence.
381    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
382        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
383        I have nevertheless tidied it up.
385    23. Added some casts to kill warnings from HP-UX ia64 compiler.
387    24. Added a man page for pcre-config.
390    Version 7.0 19-Dec-06
391    ---------------------
393     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
394        moving to gcc 4.1.1.
396     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
397        sys/time.h, which is documented as needed for this function. It doesn't
398        seem to matter on Linux, but it showed up on some releases of OS X.
400     3. It seems that there are systems where bytes whose values are greater than
401        127 match isprint() in the "C" locale. The "C" locale should be the
402        default when a C program starts up. In most systems, only ASCII printing
403        characters match isprint(). This difference caused the output from pcretest
404        to vary, making some of the tests fail. I have changed pcretest so that:
406        (a) When it is outputting text in the compiled version of a pattern, bytes
407            other than 32-126 are always shown as hex escapes.
409        (b) When it is outputting text that is a matched part of a subject string,
410            it does the same, unless a different locale has been set for the match
411            (using the /L modifier). In this case, it uses isprint() to decide.
413     4. Fixed a major bug that caused incorrect computation of the amount of memory
414        required for a compiled pattern when options that changed within the
415        pattern affected the logic of the preliminary scan that determines the
416        length. The relevant options are -x, and -i in UTF-8 mode. The result was
417        that the computed length was too small. The symptoms of this bug were
418        either the PCRE error "internal error: code overflow" from pcre_compile(),
419        or a glibc crash with a message such as "pcretest: free(): invalid next
420        size (fast)". Examples of patterns that provoked this bug (shown in
421        pcretest format) are:
423          /(?-x: )/x
424          /(?x)(?-x: \s*#\s*)/
425          /((?i)[\x{c0}])/8
426          /(?i:[\x{c0}])/8
428        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
429        is now done differently.
431     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
432        wrapper classes; (b) implement a new function in the C++ scanner that is
433        more efficient than the old way of doing things because it avoids levels of
434        recursion in the regex matching; (c) add a paragraph to the documentation
435        for the FullMatch() function.
437     6. The escape sequence \n was being treated as whatever was defined as
438        "newline". Not only was this contrary to the documentation, which states
439        that \n is character 10 (hex 0A), but it also went horribly wrong when
440        "newline" was defined as CRLF. This has been fixed.
442     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
443        was being set to -1 for the "end of line" case (supposedly a value that no
444        character can have). Though this value is never used (the check for end of
445        line is "zero bytes in current character"), it caused compiler complaints.
446        I've changed it to 0xffffffff.
448     8. In pcre_version.c, the version string was being built by a sequence of
449        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
450        string (as it is for production releases) called a macro with an empty
451        argument. The C standard says the result of this is undefined. The gcc
452        compiler treats it as an empty string (which was what was wanted) but it is
453        reported that Visual C gives an error. The source has been hacked around to
454        avoid this problem.
456     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
457        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
458        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
459        of them did).
461    10. Originally, pcretest opened its input and output without "b"; then I was
462        told that "b" was needed in some environments, so it was added for release
463        5.0 to both the input and output. (It makes no difference on Unix-like
464        systems.) Later I was told that it is wrong for the input on Windows. I've
465        now abstracted the modes into two macros, to make it easier to fiddle with
466        them, and removed "b" from the input mode under Windows.
468    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
470    12. Added -help and --help to pcretest as an official way of being reminded
471        of the options.
473    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
474        and pcrecpp.cc because they annoy compilers at high warning levels.
476    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
478    15. Fixed an occurrence of == in configure.ac that should have been = (shell
479        scripts are not C programs :-) and which was not noticed because it works
480        on Linux.
482    16. pcretest is supposed to handle any length of pattern and data line (as one
483        line or as a continued sequence of lines) by extending its input buffer if
484        necessary. This feature was broken for very long pattern lines, leading to
485        a string of junk being passed to pcre_compile() if the pattern was longer
486        than about 50K.
488    17. I have done a major re-factoring of the way pcre_compile() computes the
489        amount of memory needed for a compiled pattern. Previously, there was code
490        that made a preliminary scan of the pattern in order to do this. That was
491        OK when PCRE was new, but as the facilities have expanded, it has become
492        harder and harder to keep it in step with the real compile phase, and there
493        have been a number of bugs (see for example, 4 above). I have now found a
494        cunning way of running the real compile function in a "fake" mode that
495        enables it to compute how much memory it would need, while actually only
496        ever using a few hundred bytes of working memory and without too many
497        tests of the mode. This should make future maintenance and development
498        easier. A side effect of this work is that the limit of 200 on the nesting
499        depth of parentheses has been removed (though this was never a serious
500        limitation, I suspect). However, there is a downside: pcre_compile() now
501        runs more slowly than before (30% or more, depending on the pattern). I
502        hope this isn't a big issue. There is no effect on runtime performance.
504    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
505        newline (only possible for the last line of a file) and it was a
506        pattern that set a locale (followed by /Lsomething), pcretest crashed.
508    19. Added additional timing features to pcretest. (1) The -tm option now times
509        matching only, not compiling. (2) Both -t and -tm can be followed, as a
510        separate command line item, by a number that specifies the number of
511        repeats to use when timing. The default is 50000; this gives better
512        precision, but takes uncomfortably long for very large patterns.
514    20. Extended pcre_study() to be more clever in cases where a branch of a
515        subpattern has no definite first character. For example, (a*|b*)[cd] would
516        previously give no result from pcre_study(). Now it recognizes that the
517        first character must be a, b, c, or d.
519    21. There was an incorrect error "recursive call could loop indefinitely" if
520        a subpattern (or the entire pattern) that was being tested for matching an
521        empty string contained only one non-empty item after a nested subpattern.
522        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
523        incorrectly, because the \d was being skipped in the check.
525    22. The pcretest program now has a new pattern option /B and a command line
526        option -b, which is equivalent to adding /B to every pattern. This causes
527        it to show the compiled bytecode, without the additional information that
528        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
529        is the same as /B/I).
531    23. A new optimization is now able automatically to treat some sequences such
532        as a*b as a*+b. More specifically, if something simple (such as a character
533        or a simple class like \d) has an unlimited quantifier, and is followed by
534        something that cannot possibly match the quantified thing, the quantifier
535        is automatically "possessified".
537    24. A recursive reference to a subpattern whose number was greater than 39
538        went wrong under certain circumstances in UTF-8 mode. This bug could also
539        have affected the operation of pcre_study().
541    25. Realized that a little bit of performance could be had by replacing
542        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
544    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
546    27. Possessive quantifiers such as a++ were previously implemented by turning
547        them into atomic groups such as ($>a+). Now they have their own opcodes,
548        which improves performance. This includes the automatically created ones
549        from 23 above.
551    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
552        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
553        the first matched character to be a colon. This applied both to named and
554        numbered groups.
556    29. The ucpinternal.h header file was missing its idempotency #ifdef.
558    30. I was sent a "project" file called libpcre.a.dev which I understand makes
559        building PCRE on Windows easier, so I have included it in the distribution.
561    31. There is now a check in pcretest against a ridiculously large number being
562        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
563        loop, the loop is abandoned.
565    32. Forward references to subpatterns in conditions such as (?(2)...) where
566        subpattern 2 is defined later cause pcre_compile() to search forwards in
567        the pattern for the relevant set of parentheses. This search went wrong
568        when there were unescaped parentheses in a character class, parentheses
569        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
571    33. "Subroutine" calls and backreferences were previously restricted to
572        referencing subpatterns earlier in the regex. This restriction has now
573        been removed.
575    34. Added a number of extra features that are going to be in Perl 5.10. On the
576        whole, these are just syntactic alternatives for features that PCRE had
577        previously implemented using the Python syntax or my own invention. The
578        other formats are all retained for compatibility.
580        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
581            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
582            also .NET compatible.
584        (b) A recursion or subroutine call to a named group can now be defined as
585            (?&name) as well as (?P>name).
587        (c) A backreference to a named group can now be defined as \k<name> or
588            \k'name' as well as (?P=name). The new forms, as well as being in Perl
589            5.10, are also .NET compatible.
591        (d) A conditional reference to a named group can now use the syntax
592            (?(<name>) or (?('name') as well as (?(name).
594        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
595            groups (named and numbered) that are never evaluated inline, but can be
596            called as "subroutines" from elsewhere. In effect, the DEFINE condition
597            is always false. There may be only one alternative in such a group.
599        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
600            as the simple (?(R). The condition is true only if the most recent
601            recursion is that of the given number or name. It does not search out
602            through the entire recursion stack.
604        (g) The escape \gN or \g{N} has been added, where N is a positive or
605            negative number, specifying an absolute or relative reference.
607    35. Tidied to get rid of some further signed/unsigned compiler warnings and
608        some "unreachable code" warnings.
610    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
611        things, this adds five new scripts.
613    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
614        There were also incompatibilities regarding the handling of \Q..\E inside
615        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
616        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
618    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
619        matches an empty string, and forcibly breaks the loop. There were bugs in
620        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
621        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
622        separate and independent bugs (that affected different cases) have been
623        fixed.
625    39. Refactored the code to abolish the use of different opcodes for small
626        capturing bracket numbers. This is a tidy that I avoided doing when I
627        removed the limit on the number of capturing brackets for 3.5 back in 2001.
628        The new approach is not only tidier, it makes it possible to reduce the
629        memory needed to fix the previous bug (38).
631    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
632        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
633        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
634        mode.
636    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
637        report.
639    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
640        copy construction and assignment in the C++ wrapper.
642    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
643        couple of bugs that could have given wrong results in the "--newline=crlf"
644        case.
646    44. Added a number of casts and did some reorganization of signed/unsigned int
647        variables following suggestions from Dair Grant. Also renamed the variable
648        "this" as "item" because it is a C++ keyword.
650    45. Arranged for dftables to add
652          #include "pcre_internal.h"
654        to pcre_chartables.c because without it, gcc 4.x may remove the array
655        definition from the final binary if PCRE is built into a static library and
656        dead code stripping is activated.
658    46. For an unanchored pattern, if a match attempt fails at the start of a
659        newline sequence, and the newline setting is CRLF or ANY, and the next two
660        characters are CRLF, advance by two characters instead of one.
663    Version 6.7 04-Jul-06
664    ---------------------
666     1. In order to handle tests when input lines are enormously long, pcretest has
667        been re-factored so that it automatically extends its buffers when
668        necessary. The code is crude, but this _is_ just a test program. The
669        default size has been increased from 32K to 50K.
671     2. The code in pcre_study() was using the value of the re argument before
672        testing it for NULL. (Of course, in any sensible call of the function, it
673        won't be NULL.)
675     3. The memmove() emulation function in pcre_internal.h, which is used on
676        systems that lack both memmove() and bcopy() - that is, hardly ever -
677        was missing a "static" storage class specifier.
679     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
680        containing an extended class (one that cannot be represented by a bitmap
681        because it contains high-valued characters or Unicode property items, e.g.
682        [\pZ]). Almost always one would set UTF-8 mode when processing such a
683        pattern, but PCRE should not loop if you do not (it no longer does).
684        [Detail: two cases were found: (a) a repeated subpattern containing an
685        extended class; (b) a recursive reference to a subpattern that followed a
686        previous extended class. It wasn't skipping over the extended class
687        correctly when UTF-8 mode was not set.]
689     5. A negated single-character class was not being recognized as fixed-length
690        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
691        compile error "lookbehind assertion is not fixed length".
693     6. The RunPerlTest auxiliary script was showing an unexpected difference
694        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
695        write a Perl script that can interpret lines of an input file either as
696        byte characters or as UTF-8, which is what "perltest" was being required to
697        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
698        can't do is switch easily at run time between having the "use utf8;" pragma
699        or not. In the end, I fudged it by using the RunPerlTest script to insert
700        "use utf8;" explicitly for the UTF-8 tests.
702     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
703        the end of the subject string, contrary to the documentation and to what
704        Perl does. This was true of both matching functions. Now it matches only at
705        the start of the subject and immediately after *internal* newlines.
707     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
708        a pointer to an int instead of a pointer to an unsigned long int. This
709        caused problems on 64-bit systems.
711     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
712        instance of the 'standard' template library not being so standard".
714    10. There was no check on the number of named subpatterns nor the maximum
715        length of a subpattern name. The product of these values is used to compute
716        the size of the memory block for a compiled pattern. By supplying a very
717        long subpattern name and a large number of named subpatterns, the size
718        computation could be caused to overflow. This is now prevented by limiting
719        the length of names to 32 characters, and the number of named subpatterns
720        to 10,000.
722    11. Subpatterns that are repeated with specific counts have to be replicated in
723        the compiled pattern. The size of memory for this was computed from the
724        length of the subpattern and the repeat count. The latter is limited to
725        65535, but there was no limit on the former, meaning that integer overflow
726        could in principle occur. The compiled length of a repeated subpattern is
727        now limited to 30,000 bytes in order to prevent this.
729    12. Added the optional facility to have named substrings with the same name.
731    13. Added the ability to use a named substring as a condition, using the
732        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
733        are numbers (not recommended). Forward references are permitted.
735    14. Added forward references in named backreferences (if you see what I mean).
737    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
738        pattern could run off the end of the subject. For example, the pattern
739        "(?s)(.{1,5})"8 did this with the subject "ab".
741    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
742        PCRE_CASELESS was set when matching characters that were quantified with ?
743        or *.
745    17. A character class other than a single negated character that had a minimum
746        but no maximum quantifier - for example [ab]{6,} - was not handled
747        correctly by pce_dfa_exec(). It would match only one character.
749    18. A valid (though odd) pattern that looked like a POSIX character
750        class but used an invalid character after [ (for example [[,abc,]]) caused
751        pcre_compile() to give the error "Failed: internal error: code overflow" or
752        in some cases to crash with a glibc free() error. This could even happen if
753        the pattern terminated after [[ but there just happened to be a sequence of
754        letters, a binary zero, and a closing ] in the memory that followed.
756    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
757        over the years. Originally (before any Unicode support), just the bottom 8
758        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
759        output from "man perlunicode" includes this:
761          The regular expression compiler produces polymorphic opcodes.  That
762          is, the pattern adapts to the data and automatically switches to
763          the Unicode character scheme when presented with Unicode data--or
764          instead uses a traditional byte scheme when presented with byte
765          data.
767        Sadly, a wide octal escape does not cause a switch, and in a string with
768        no other multibyte characters, these octal escapes are treated as before.
769        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
770        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
771        Unicode string.
773        I have not perpetrated such confusion in PCRE. Up till now, it took just
774        the bottom 8 bits, as in old Perl. I have now made octal escapes with
775        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
776        translate to the appropriate multibyte character.
778    29. Applied some refactoring to reduce the number of warnings from Microsoft
779        and Borland compilers. This has included removing the fudge introduced
780        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
781        a warning about an unused variable.
783    21. PCRE has not included VT (character 0x0b) in the set of whitespace
784        characters since release 4.0, because Perl (from release 5.004) does not.
785        [Or at least, is documented not to: some releases seem to be in conflict
786        with the documentation.] However, when a pattern was studied with
787        pcre_study() and all its branches started with \s, PCRE still included VT
788        as a possible starting character. Of course, this did no harm; it just
789        caused an unnecessary match attempt.
791    22. Removed a now-redundant internal flag bit that recorded the fact that case
792        dependency changed within the pattern. This was once needed for "required
793        byte" processing, but is no longer used. This recovers a now-scarce options
794        bit. Also moved the least significant internal flag bit to the most-
795        significant bit of the word, which was not previously used (hangover from
796        the days when it was an int rather than a uint) to free up another bit for
797        the future.
799    23. Added support for CRLF line endings as well as CR and LF. As well as the
800        default being selectable at build time, it can now be changed at runtime
801        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
802        specify that it is scanning data with non-default line endings.
804    24. Changed the definition of CXXLINK to make it agree with the definition of
805        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
807    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
808        recursions. This makes a big different to stack usage for some patterns.
810    26. If a subpattern containing a named recursion or subroutine reference such
811        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
812        the space required for the compiled pattern went wrong and gave too small a
813        value. Depending on the environment, this could lead to "Failed: internal
814        error: code overflow at offset 49" or "glibc detected double free or
815        corruption" errors.
817    27. Applied patches from Google (a) to support the new newline modes and (b) to
818        advance over multibyte UTF-8 characters in GlobalReplace.
820    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
821        difference for some implementation of PCRE in some Windows version.
823    29. Added some extra testing facilities to pcretest:
825        \q<number>   in a data line sets the "match limit" value
826        \Q<number>   in a data line sets the "match recursion limt" value
827        -S <number>  sets the stack size, where <number> is in megabytes
829        The -S option isn't available for Windows.
832    Version 6.6 06-Feb-06
833    ---------------------
835     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
836        in pcreposix.h. I have copied the definition from pcre.h.
838     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
839        because pcre.h is no longer a built file.
841     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
842        not normally included in the compiled code.
845    Version 6.5 01-Feb-06
846    ---------------------
848     1. When using the partial match feature with pcre_dfa_exec(), it was not
849        anchoring the second and subsequent partial matches at the new starting
850        point. This could lead to incorrect results. For example, with the pattern
851        /1234/, partially matching against "123" and then "a4" gave a match.
853     2. Changes to pcregrep:
855        (a) All non-match returns from pcre_exec() were being treated as failures
856            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
857            error message is output. Some extra information is given for the
858            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
859            probably the only errors that are likely to be caused by users (by
860            specifying a regex that has nested indefinite repeats, for instance).
861            If there are more than 20 of these errors, pcregrep is abandoned.
863        (b) A binary zero was treated as data while matching, but terminated the
864            output line if it was written out. This has been fixed: binary zeroes
865            are now no different to any other data bytes.
867        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
868            used to set a locale for matching. The --locale=xxxx long option has
869            been added (no short equivalent) to specify a locale explicitly on the
870            pcregrep command, overriding the environment variables.
872        (d) When -B was used with -n, some line numbers in the output were one less
873            than they should have been.
875        (e) Added the -o (--only-matching) option.
877        (f) If -A or -C was used with -c (count only), some lines of context were
878            accidentally printed for the final match.
880        (g) Added the -H (--with-filename) option.
882        (h) The combination of options -rh failed to suppress file names for files
883            that were found from directory arguments.
885        (i) Added the -D (--devices) and -d (--directories) options.
887        (j) Added the -F (--fixed-strings) option.
889        (k) Allow "-" to be used as a file name for -f as well as for a data file.
891        (l) Added the --colo(u)r option.
893        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
894            is not present by default.
896     3. A nasty bug was discovered in the handling of recursive patterns, that is,
897        items such as (?R) or (?1), when the recursion could match a number of
898        alternatives. If it matched one of the alternatives, but subsequently,
899        outside the recursion, there was a failure, the code tried to back up into
900        the recursion. However, because of the way PCRE is implemented, this is not
901        possible, and the result was an incorrect result from the match.
903        In order to prevent this happening, the specification of recursion has
904        been changed so that all such subpatterns are automatically treated as
905        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
907     4. I had overlooked the fact that, in some locales, there are characters for
908        which isalpha() is true but neither isupper() nor islower() are true. In
909        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
910        and ordfeminine) are like this. This affected the treatment of \w and \W
911        when they appeared in character classes, but not when they appeared outside
912        a character class. The bit map for "word" characters is now created
913        separately from the results of isalnum() instead of just taking it from the
914        upper, lower, and digit maps. (Plus the underscore character, of course.)
916     5. The above bug also affected the handling of POSIX character classes such as
917        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
918        permanent tables. Instead, the bit maps for such a class were previously
919        created as the appropriate unions of the upper, lower, and digit bitmaps.
920        Now they are created by subtraction from the [[:word:]] class, which has
921        its own bitmap.
923     6. The [[:blank:]] character class matches horizontal, but not vertical space.
924        It is created by subtracting the vertical space characters (\x09, \x0a,
925        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
926        subtraction was done in the overall bitmap for a character class, meaning
927        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
928        be recognized. This bug has been fixed.
930     7. Patches from the folks at Google:
932          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
933          real life, but is still worth protecting against".
935          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
936          regular expressions".
938          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
939          have it.
941          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
942          "configure" and the latter not, in order to fix a problem somebody had
943          with compiling the Arg class on HP-UX.
945          (e) Improve the error-handling of the C++ wrapper a little bit.
947          (f) New tests for checking recursion limiting.
949     8. The pcre_memmove() function, which is used only if the environment does not
950        have a standard memmove() function (and is therefore rarely compiled),
951        contained two bugs: (a) use of int instead of size_t, and (b) it was not
952        returning a result (though PCRE never actually uses the result).
954     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
955        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
956        returned instead of calling malloc() with an overflowing number that would
957        most likely cause subsequent chaos.
959    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
961    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
962        with this option is matched, the nmatch and pmatch options of regexec() are
963        ignored.
965    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
966        provided in case anyone wants to the the POSIX interface with UTF-8
967        strings.
969    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
970        C++ linking (needed for some HP-UX environments).
972    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
973        (unused parameter) and in the pcre_printint() function (omitted "default"
974        switch label when the default is to do nothing).
976    15. Added some code to make it possible, when PCRE is compiled as a C++
977        library, to replace subject pointers for pcre_exec() with a smart pointer
978        class, thus making it possible to process discontinuous strings.
980    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
981        much the same function. They were added by different people who were trying
982        to make PCRE easy to compile on non-Unix systems. It has been suggested
983        that PCRE_EXPORT be abolished now that there is more automatic apparatus
984        for compiling on Windows systems. I have therefore replaced it with
985        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
986        defaults to "extern" for C or "extern C" for C++, which works fine on
987        Unix-like systems. It is now possible to override the value of PCRE_DATA_
988        SCOPE with something explicit in config.h. In addition:
990        (a) pcreposix.h still had just "extern" instead of either of these macros;
991            I have replaced it with PCRE_DATA_SCOPE.
993        (b) Functions such as _pcre_xclass(), which are internal to the library,
994            but external in the C sense, all had PCRE_EXPORT in their definitions.
995            This is apparently wrong for the Windows case, so I have removed it.
996            (It makes no difference on Unix-like systems.)
998    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
999        of recursive calls to match(). This is different to MATCH_LIMIT because
1000        that limits the total number of calls to match(), not all of which increase
1001        the depth of recursion. Limiting the recursion depth limits the amount of
1002        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1003        when PCRE is compiled, and changed at run time. A patch from Google adds
1004        this functionality to the C++ interface.
1006    18. Changes to the handling of Unicode character properties:
1008        (a) Updated the table to Unicode 4.1.0.
1010        (b) Recognize characters that are not in the table as "Cn" (undefined).
1012        (c) I revised the way the table is implemented to a much improved format
1013            which includes recognition of ranges. It now supports the ranges that
1014            are defined in UnicodeData.txt, and it also amalgamates other
1015            characters into ranges. This has reduced the number of entries in the
1016            table from around 16,000 to around 3,000, thus reducing its size
1017            considerably. I realized I did not need to use a tree structure after
1018            all - a binary chop search is just as efficient. Having reduced the
1019            number of entries, I extended their size from 6 bytes to 8 bytes to
1020            allow for more data.
1022        (d) Added support for Unicode script names via properties such as \p{Han}.
1024    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1025        matching that character.
1027    20. When matching a repeated Unicode property with a minimum greater than zero,
1028        (for example \pL{2,}), PCRE could look past the end of the subject if it
1029        reached it while seeking the minimum number of characters. This could
1030        happen only if some of the characters were more than one byte long, because
1031        there is a check for at least the minimum number of bytes.
1033    21. Refactored the implementation of \p and \P so as to be more general, to
1034        allow for more different types of property in future. This has changed the
1035        compiled form incompatibly. Anybody with saved compiled patterns that use
1036        \p or \P will have to recompile them.
1038    22. Added "Any" and "L&" to the supported property types.
1040    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1041        but give a compile time error if the value is greater than 0xff.
1043    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1044        accidentally not being installed or uninstalled.
1046    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1047        made were to insert the current release number. This seemed silly, because
1048        it made things harder for people building PCRE on systems that don't run
1049        "configure". I have turned pcre.h into a distributed file, no longer built
1050        by "configure", with the version identification directly included. There is
1051        no longer a pcre.h.in file.
1053        However, this change necessitated a change to the pcre-config script as
1054        well. It is built from pcre-config.in, and one of the substitutions was the
1055        release number. I have updated configure.ac so that ./configure now finds
1056        the release number by grepping pcre.h.
1058    26. Added the ability to run the tests under valgrind.
1061    Version 6.4 05-Sep-05
1062    ---------------------
1064     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1065        "--" to be printed when multiple files were scanned, even when none of the
1066        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1067        consider it to be a bug, and have restored the previous behaviour.
1069     2. A couple of code tidies to get rid of compiler warnings.
1071     3. The pcretest program used to cheat by referring to symbols in the library
1072        whose names begin with _pcre_. These are internal symbols that are not
1073        really supposed to be visible externally, and in some environments it is
1074        possible to suppress them. The cheating is now confined to including
1075        certain files from the library's source, which is a bit cleaner.
1077     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1078        file's purpose clearer.
1080     5. Reorganized pcre_ucp_findchar().
1083    Version 6.3 15-Aug-05
1084    ---------------------
1086     1. The file libpcre.pc.in did not have general read permission in the tarball.
1088     2. There were some problems when building without C++ support:
1090        (a) If C++ support was not built, "make install" and "make test" still
1091            tried to test it.
1093        (b) There were problems when the value of CXX was explicitly set. Some
1094            changes have been made to try to fix these, and ...
1096        (c) --disable-cpp can now be used to explicitly disable C++ support.
1098        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1099            backslash in a target when C++ was disabled. This confuses some
1100            versions of "make", apparently. Using an intermediate variable solves
1101            this. (Same for CPP_LOBJ.)
1103     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1104        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1105        necessary on certain architectures.
1107     4. Added a setting of -export-symbols-regex to the link command to remove
1108        those symbols that are exported in the C sense, but actually are local
1109        within the library, and not documented. Their names all begin with
1110        "_pcre_". This is not a perfect job, because (a) we have to except some
1111        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1112        available (and never for static libraries). I have made a note to try to
1113        find a way round (a) in the future.
1116    Version 6.2 01-Aug-05
1117    ---------------------
1119     1. There was no test for integer overflow of quantifier values. A construction
1120        such as {1111111111111111} would give undefined results. What is worse, if
1121        a minimum quantifier for a parenthesized subpattern overflowed and became
1122        negative, the calculation of the memory size went wrong. This could have
1123        led to memory overwriting.
1125     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1127     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1128        operating environments where this matters.
1130     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1131        PCRE options from within the C++ wrapper.
1133     5. Named capturing subpatterns were not being correctly counted when a pattern
1134        was compiled. This caused two problems: (a) If there were more than 100
1135        such subpatterns, the calculation of the memory needed for the whole
1136        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1137        back references of the form \12, where the number was greater than 9, were
1138        not recognized as back references, even though there were sufficient
1139        previous subpatterns.
1141     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1142        versions of gcc, e.g. 2.95.4.
1145    Version 6.1 21-Jun-05
1146    ---------------------
1148     1. There was one reference to the variable "posix" in pcretest.c that was not
1149        surrounded by "#if !defined NOPOSIX".
1151     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1152        the cross-check on the old pcre_info() function, for the benefit of the
1153        cut-down version of PCRE that is currently imported into Exim.
1155     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1156        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1157        patterns that start (?i) but I don't think that matters. The use of (?i) is
1158        just an example; this all applies to the other options as well.
1160     4. Since libtool seems to echo the compile commands it is issuing, the output
1161        from "make" can be reduced a bit by putting "@" in front of each libtool
1162        compile command.
1164     5. Patch from the folks at Google for configure.in to be a bit more thorough
1165        in checking for a suitable C++ installation before trying to compile the
1166        C++ stuff. This should fix a reported problem when a compiler was present,
1167        but no suitable headers.
1169     6. The man pages all had just "PCRE" as their title. I have changed them to
1170        be the relevant file name. I have also arranged that these names are
1171        retained in the file doc/pcre.txt, which is a concatenation in text format
1172        of all the man pages except the little individual ones for each function.
1174     7. The NON-UNIX-USE file had not been updated for the different set of source
1175        files that come with release 6. I also added a few comments about the C++
1176        wrapper.
1179    Version 6.0 07-Jun-05
1180    ---------------------
1182     1. Some minor internal re-organization to help with my DFA experiments.
1184     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1185        didn't matter for the library itself when fully configured, but did matter
1186        when compiling without UCP support, or within Exim, where the ucp files are
1187        not imported.
1189     3. Refactoring of the library code to split up the various functions into
1190        different source modules. The addition of the new DFA matching code (see
1191        below) to a single monolithic source would have made it really too
1192        unwieldy, quite apart from causing all the code to be include in a
1193        statically linked application, when only some functions are used. This is
1194        relevant even without the DFA addition now that patterns can be compiled in
1195        one application and matched in another.
1197        The downside of splitting up is that there have to be some external
1198        functions and data tables that are used internally in different modules of
1199        the library but which are not part of the API. These have all had their
1200        names changed to start with "_pcre_" so that they are unlikely to clash
1201        with other external names.
1203     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1204        a different (DFA) algorithm. Although it is slower than the original
1205        function, it does have some advantages for certain types of matching
1206        problem.
1208     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1209        including restarting after a partial match.
1211     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1212        defined when compiling for Windows was sent to me. I have put it into the
1213        code, though I have no means of testing or verifying it.
1215     7. Added the pcre_refcount() auxiliary function.
1217     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1218        match before or at the first newline in the subject string. In pcretest,
1219        the /f option on a pattern can be used to set this.
1221     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1222        would behave wrongly. This has been present in PCRE since release 4.0.
1224    10. A number of changes to the pcregrep command:
1226        (a) Refactored how -x works; insert ^(...)$ instead of setting
1227            PCRE_ANCHORED and checking the length, in preparation for adding
1228            something similar for -w.
1230        (b) Added the -w (match as a word) option.
1232        (c) Refactored the way lines are read and buffered so as to have more
1233            than one at a time available.
1235        (d) Implemented a pcregrep test script.
1237        (e) Added the -M (multiline match) option. This allows patterns to match
1238            over several lines of the subject. The buffering ensures that at least
1239            8K, or the rest of the document (whichever is the shorter) is available
1240            for matching (and similarly the previous 8K for lookbehind assertions).
1242        (f) Changed the --help output so that it now says
1244              -w, --word-regex(p)
1246            instead of two lines, one with "regex" and the other with "regexp"
1247            because that confused at least one person since the short forms are the
1248            same. (This required a bit of code, as the output is generated
1249            automatically from a table. It wasn't just a text change.)
1251        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1252            option but starts with a hyphen. Could be a pattern or a path name
1253            starting with a hyphen, for instance.
1255        (h) "-" can be given as a file name to represent stdin.
1257        (i) When file names are being printed, "(standard input)" is used for
1258            the standard input, for compatibility with GNU grep. Previously
1259            "<stdin>" was used.
1261        (j) The option --label=xxx can be used to supply a name to be used for
1262            stdin when file names are being printed. There is no short form.
1264        (k) Re-factored the options decoding logic because we are going to add
1265            two more options that take data. Such options can now be given in four
1266            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1268        (l) Added the -A, -B, and -C options for requesting that lines of context
1269            around matches be printed.
1271        (m) Added the -L option to print the names of files that do not contain
1272            any matching lines, that is, the complement of -l.
1274        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1275            continue to scan other files.
1277        (o) The -s option was incorrectly implemented. For compatibility with other
1278            greps, it now suppresses the error message for a non-existent or non-
1279            accessible file (but not the return code). There is a new option called
1280            -q that suppresses the output of matching lines, which was what -s was
1281            previously doing.
1283        (p) Added --include and --exclude options to specify files for inclusion
1284            and exclusion when recursing.
1286    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1287        Hopefully, it now does.
1289    12. Missing cast in pcre_study().
1291    13. Added an "uninstall" target to the makefile.
1293    14. Replaced "extern" in the function prototypes in Makefile.in with
1294        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1295        world, but is set differently for Windows.
1297    15. Added a second compiling function called pcre_compile2(). The only
1298        difference is that it has an extra argument, which is a pointer to an
1299        integer error code. When there is a compile-time failure, this is set
1300        non-zero, in addition to the error test pointer being set to point to an
1301        error message. The new argument may be NULL if no error number is required
1302        (but then you may as well call pcre_compile(), which is now just a
1303        wrapper). This facility is provided because some applications need a
1304        numeric error indication, but it has also enabled me to tidy up the way
1305        compile-time errors are handled in the POSIX wrapper.
1307    16. Added VPATH=.libs to the makefile; this should help when building with one
1308        prefix path and installing with another. (Or so I'm told by someone who
1309        knows more about this stuff than I do.)
1311    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1312        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1313        match everything, including newlines. This is not POSIX-compatible, but
1314        somebody wanted the feature. From pcretest it can be activated by using
1315        both the P and the s flags.
1317    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1319    19. libpcre.pc was being incorrectly installed as executable.
1321    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1322        it now also looks for '\r' so that it will work unmodified on Windows.
1324    21. Added Google's contributed C++ wrapper to the distribution.
1326    22. Added some untidy missing memory free() calls in pcretest, to keep
1327        Electric Fence happy when testing.
1331    Version 5.0 13-Sep-04
1332    ---------------------
1334     1. Internal change: literal characters are no longer packed up into items
1335        containing multiple characters in a single byte-string. Each character
1336        is now matched using a separate opcode. However, there may be more than one
1337        byte in the character in UTF-8 mode.
1339     2. The pcre_callout_block structure has two new fields: pattern_position and
1340        next_item_length. These contain the offset in the pattern to the next match
1341        item, and its length, respectively.
1343     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1344        insertion of callouts before each pattern item. Added the /C option to
1345        pcretest to make use of this.
1347     4. On the advice of a Windows user, the lines
1349          #if defined(_WIN32) || defined(WIN32)
1350          _setmode( _fileno( stdout ), 0x8000 );
1351          #endif  /* defined(_WIN32) || defined(WIN32) */
1353        have been added to the source of pcretest. This apparently does useful
1354        magic in relation to line terminators.
1356     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1357        for the benefit of those environments where the "b" makes a difference.
1359     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1360        to know about it. I have put a hack into configure.in that adds in code
1361        to set GCC=yes if CC=icc. This seems to end up at a point in the
1362        generated configure script that is early enough to affect the setting of
1363        compiler options, which is what is needed, but I have no means of testing
1364        whether it really works. (The user who reported this had patched the
1365        generated configure script, which of course I cannot do.)
1367        LATER: After change 22 below (new libtool files), the configure script
1368        seems to know about icc (and also ecc). Therefore, I have commented out
1369        this hack in configure.in.
1371     7. Added support for pkg-config (2 patches were sent in).
1373     8. Negated POSIX character classes that used a combination of internal tables
1374        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1375        [[:^ascii]]. Typically, they would match almost any characters. The other
1376        POSIX classes were not broken in this way.
1378     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1379        to find the match, as PCRE was deluded into thinking that the match had to
1380        start at the start point or following a newline. The same bug applied to
1381        patterns with negative forward assertions or any backward assertions
1382        preceding ".*" at the start, unless the pattern required a fixed first
1383        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1385    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1386        starting at the last subject character, bytes beyond the end of the subject
1387        string were read.
1389    11. Renamed the variable "class" as "classbits" to make life easier for C++
1390        users. (Previously there was a macro definition, but it apparently wasn't
1391        enough.)
1393    12. Added the new field "tables" to the extra data so that tables can be passed
1394        in at exec time, or the internal tables can be re-selected. This allows
1395        a compiled regex to be saved and re-used at a later time by a different
1396        program that might have everything at different addresses.
1398    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1399        -R library as well as a -L library.
1401    14. The debugging options of pcretest (-d on the command line or D on a
1402        pattern) showed incorrect output for anything following an extended class
1403        that contained multibyte characters and which was followed by a quantifier.
1405    15. Added optional support for general category Unicode character properties
1406        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1407        support. It adds about 90K to the size of the library. The meanings of the
1408        inbuilt class escapes such as \d and \s have NOT been changed.
1410    16. Updated pcredemo.c to include calls to free() to release the memory for the
1411        compiled pattern.
1413    17. The generated file chartables.c was being created in the source directory
1414        instead of in the building directory. This caused the build to fail if the
1415        source directory was different from the building directory, and was
1416        read-only.
1418    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1419        file. No doubt somebody will tell me if they don't make sense... Also added
1420        Dan Mooney's comments about building on OpenVMS.
1422    19. Added support for partial matching via the PCRE_PARTIAL option for
1423        pcre_exec() and the \P data escape in pcretest.
1425    20. Extended pcretest with 3 new pattern features:
1427        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1428              write the compiled pattern to the file whose name is "rest-of-line".
1429              This is a straight binary dump of the data, with the saved pointer to
1430              the character tables forced to be NULL. The study data, if any, is
1431              written too. After writing, pcretest reads a new pattern.
1433        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1434              compiled pattern from the given file. There must not be any
1435              occurrences of "<" in the file name (pretty unlikely); if there are,
1436              pcretest will instead treat the initial "<" as a pattern delimiter.
1437              After reading in the pattern, pcretest goes on to read data lines as
1438              usual.
1440        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1441              and 16-bit fields in a compiled pattern, to simulate a pattern that
1442              was compiled on a host of opposite endianness.
1444    21. The pcre-exec() function can now cope with patterns that were compiled on
1445        hosts of opposite endianness, with this restriction:
1447          As for any compiled expression that is saved and used later, the tables
1448          pointer field cannot be preserved; the extra_data field in the arguments
1449          to pcre_exec() should be used to pass in a tables address if a value
1450          other than the default internal tables were used at compile time.
1452    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1453        now diagnosed as an error. Previously, most of the time, a negative number
1454        would have been treated as zero, but if in addition "ovector" was passed as
1455        NULL, a crash could occur.
1457    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1458        new versions from the libtool 1.5 distribution (the last one is a copy of
1459        a file called libtool.m4). This seems to have fixed the need to patch
1460        "configure" to support Darwin 1.3 (which I used to do). However, I still
1461        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1462        workstation).
1464    24. Changed the PCRE licence to be the more standard "BSD" licence.
1467    Version 4.5 01-Dec-03
1468    ---------------------
1470     1. There has been some re-arrangement of the code for the match() function so
1471        that it can be compiled in a version that does not call itself recursively.
1472        Instead, it keeps those local variables that need separate instances for
1473        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1474        needs to "recurse". Keeping track of where control must go is done by means
1475        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1476        hide most of the details from the main code, and operates only if
1477        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1478        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1479        operating.
1481        To make it easier for callers to provide specially tailored get/free
1482        functions for this usage, two new functions, pcre_stack_malloc, and
1483        pcre_stack_free, are used. They are always called in strict stacking order,
1484        and the size of block requested is always the same.
1486        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1487        PCRE has been compiled to use the stack or the heap for recursion. The
1488        -C option of pcretest uses this to show which version is compiled.
1490        A new data escape \S, is added to pcretest; it causes the amounts of store
1491        obtained and freed by both kinds of malloc/free at match time to be added
1492        to the output.
1494     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1495        what's available on my current Linux desktop machine.
1497     3. When matching a UTF-8 string, the test for a valid string at the start has
1498        been extended. If start_offset is not zero, PCRE now checks that it points
1499        to a byte that is the start of a UTF-8 character. If not, it returns
1500        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1501        this is necessary because there may be backward assertions in the pattern.
1502        When matching the same subject several times, it may save resources to use
1503        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1505     4. The code for checking the validity of UTF-8 strings has been tightened so
1506        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1507        containing "overlong sequences".
1509     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1510        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1511        should have been "&", but it just so happened that all the cases this let
1512        through by mistake were picked up later in the function.
1514     6. I had used a variable called "isblank" - this is a C99 function, causing
1515        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1517     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1518        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1519        so the version is shown; (c) stop "make test" echoing "./RunTest".
1521     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1523     9. The prototype for memmove() for systems that don't have it was using
1524        size_t, but the inclusion of the header that defines size_t was later. I've
1525        moved the #includes for the C headers earlier to avoid this.
1527    10. Added some adjustments to the code to make it easier to compiler on certain
1528        special systems:
1530          (a) Some "const" qualifiers were missing.
1531          (b) Added the macro EXPORT before all exported functions; by default this
1532              is defined to be empty.
1533          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1534              that it reads its output file name as an argument instead of writing
1535              to the standard output and assuming this can be redirected.
1537    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1538        class containing characters with values greater than 255, PCRE compilation
1539        went into a loop.
1541    12. A recursive reference to a subpattern that was within another subpattern
1542        that had a minimum quantifier of zero caused PCRE to crash. For example,
1543        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1544        recursion. If the recursively-called subpattern itself had a zero repeat,
1545        that was OK.
1547    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1548        buffer into which it was copied (for escape processing) was still set at
1549        1024, so long lines caused crashes.
1551    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1552        "internal error: code overflow...". This applied to any character class
1553        that was followed by a possessive quantifier.
1555    15. Modified the Makefile to add libpcre.la as a prerequisite for
1556        libpcreposix.la because I was told this is needed for a parallel build to
1557        work.
1559    16. If a pattern that contained .* following optional items at the start was
1560        studied, the wrong optimizing data was generated, leading to matching
1561        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1562        matching string must start with a or b or c. The correct conclusion for
1563        this pattern is that a match can start with any character.
1566    Version 4.4 13-Aug-03
1567    ---------------------
1569     1. In UTF-8 mode, a character class containing characters with values between
1570        127 and 255 was not handled correctly if the compiled pattern was studied.
1571        In fixing this, I have also improved the studying algorithm for such
1572        classes (slightly).
1574     2. Three internal functions had redundant arguments passed to them. Removal
1575        might give a very teeny performance improvement.
1577     3. Documentation bug: the value of the capture_top field in a callout is *one
1578        more than* the number of the hightest numbered captured substring.
1580     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1581        in incorrectly linking with a previously installed version. They now link
1582        explicitly with libpcre.la.
1584     5. configure.in no longer needs to recognize Cygwin specially.
1586     6. A problem in pcre.in for Windows platforms is fixed.
1588     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1589        pcretest, it used to include the size of the study block as part of its
1590        output. Unfortunately, the structure contains a field that has a different
1591        size on different hardware architectures. This meant that the tests that
1592        showed this size failed. As the block is currently always of a fixed size,
1593        this information isn't actually particularly useful in pcretest output, so
1594        I have just removed it.
1596     8. Three pre-processor statements accidentally did not start in column 1.
1597        Sadly, there are *still* compilers around that complain, even though
1598        standard C has not required this for well over a decade. Sigh.
1600     9. In pcretest, the code for checking callouts passed small integers in the
1601        callout_data field, which is a void * field. However, some picky compilers
1602        complained about the casts involved for this on 64-bit systems. Now
1603        pcretest passes the address of the small integer instead, which should get
1604        rid of the warnings.
1606    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1607        both compile and run time, and gives an error if an invalid UTF-8 sequence
1608        is found. There is a option for disabling this check in cases where the
1609        string is known to be correct and/or the maximum performance is wanted.
1611    11. In response to a bug report, I changed one line in Makefile.in from
1613            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1614        to
1615            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1617        to look similar to other lines, but I have no way of telling whether this
1618        is the right thing to do, as I do not use Windows. No doubt I'll get told
1619        if it's wrong...
1622  Version 4.3 21-May-03  Version 4.3 21-May-03
1623  ---------------------  ---------------------

Removed from v.69  
changed lines
  Added in v.226

  ViewVC Help
Powered by ViewVC 1.1.5