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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 12-Nov-07
5    ---------------------
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
11    Version 7.4 21-Sep-07
12    ---------------------
14    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
15        means that a class such as [\s] counted as "explicit reference to CR or
16        LF". That isn't really right - the whole point of the change was to try to
17        help when there was an actual mention of one of the two characters. So now
18        the change happens only if \r or \n (or a literal CR or LF) character is
19        encountered.
21    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
22        of both had grown to the point where there were only 3 bits left.
23        Fortunately, there was spare space in the data structure, and so I have
24        moved the internal flags into a new 16-bit field to free up more option
25        bits.
27    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
28        but did not set the internal JCHANGED flag - either of these is enough to
29        control the way the "get" function works - but the PCRE_INFO_JCHANGED
30        facility is supposed to tell if (?J) was ever used, so now (?J) at the
31        start sets both bits.
33    4.  Added options (at build time, compile time, exec time) to change \R from
34        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
36    5.  doc/pcresyntax.html was missing from the distribution.
38    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
39        compatibility, even though it is no longer used.
41    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
42        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
43        windows.h file is present (where different names are used). [This was
44        reversed later after testing - see 16 below.]
46    8.  Changed all #include <config.h> to #include "config.h". There were also
47        some further <pcre.h> cases that I changed to "pcre.h".
49    9.  When pcregrep was used with the --colour option, it missed the line ending
50        sequence off the lines that it output.
52    10. It was pointed out to me that arrays of string pointers cause lots of
53        relocations when a shared library is dynamically loaded. A technique of
54        using a single long string with a table of offsets can drastically reduce
55        these. I have refactored PCRE in four places to do this. The result is
56        dramatic:
58          Originally:                          290
59          After changing UCP table:            187
60          After changing error message table:   43
61          After changing table of "verbs"       36
62          After changing table of Posix names   22
64        Thanks to the folks working on Gregex for glib for this insight.
66    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
67        unicode-properties was also set.
69    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
71    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
72        checked only for CRLF.
74    14. Added casts to pcretest.c to avoid compiler warnings.
76    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
78    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
79        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
80        entirely. This removes changes made in 7 above.
82    17. The CMake files have been updated, and there is now more information about
83        building with CMake in the NON-UNIX-USE document.
86    Version 7.3 28-Aug-07
87    ---------------------
89     1. In the rejigging of the build system that eventually resulted in 7.1, the
90        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
91        brackets there is not right, since it causes compilers to look for an
92        installed pcre.h, not the version that is in the source that is being
93        compiled (which of course may be different). I have changed it back to:
95          #include "pcre.h"
97        I have a vague recollection that the change was concerned with compiling in
98        different directories, but in the new build system, that is taken care of
99        by the VPATH setting the Makefile.
101     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
102        when the subject happened to end in the byte 0x85 (e.g. if the last
103        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
104        characters but of course it shouldn't be taken as a newline when it is part
105        of another character. The bug was that, for an unlimited repeat of . in
106        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
107        characters when looking for a newline.
109     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
111     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
112        in debug output.
114     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
115        long printing in the pcrecpp unittest when running under MinGW.
117     6. ESC_K was left out of the EBCDIC table.
119     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
120        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
121        limit also applies to "virtual nesting" when a pattern is recursive, and in
122        this case 1000 isn't so big. I have been able to remove this limit at the
123        expense of backing off one optimization in certain circumstances. Normally,
124        when pcre_exec() would call its internal match() function recursively and
125        immediately return the result unconditionally, it uses a "tail recursion"
126        feature to save stack. However, when a subpattern that can match an empty
127        string has an unlimited repetition quantifier, it no longer makes this
128        optimization. That gives it a stack frame in which to save the data for
129        checking that an empty string has been matched. Previously this was taken
130        from the 1000-entry workspace that had been reserved. So now there is no
131        explicit limit, but more stack is used.
133     8. Applied Daniel's patches to solve problems with the import/export magic
134        syntax that is required for Windows, and which was going wrong for the
135        pcreposix and pcrecpp parts of the library. These were overlooked when this
136        problem was solved for the main library.
138     9. There were some crude static tests to avoid integer overflow when computing
139        the size of patterns that contain repeated groups with explicit upper
140        limits. As the maximum quantifier is 65535, the maximum group length was
141        set at 30,000 so that the product of these two numbers did not overflow a
142        32-bit integer. However, it turns out that people want to use groups that
143        are longer than 30,000 bytes (though not repeat them that many times).
144        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
145        made it possible to implement the integer overflow checks in a much more
146        dynamic way, which I have now done. The artificial limitation on group
147        length has been removed - we now have only the limit on the total length of
148        the compiled pattern, which depends on the LINK_SIZE setting.
150    10. Fixed a bug in the documentation for get/copy named substring when
151        duplicate names are permitted. If none of the named substrings are set, the
152        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
153        empty string.
155    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
156        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
157        because the ] is interpreted as the first data character and the
158        terminating ] is not found. PCRE has been made compatible with Perl in this
159        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
160        cause memory overwriting.
162    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
163        string has been matched (to stop an infinite loop). It was not recognizing
164        a conditional subpattern that could match an empty string if that
165        subpattern was within another subpattern. For example, it looped when
166        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
167        condition was not nested. This bug has been fixed.
169    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
170        past the start of the subject in the presence of bytes with the top bit
171        set, for example "\x8aBCD".
173    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
174        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
176    14. Optimized (?!) to (*FAIL).
178    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
179        This restricts code points to be within the range 0 to 0x10FFFF, excluding
180        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
181        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
182        does: it's just the validity check that is more restrictive.
184    16. Inserted checks for integer overflows during escape sequence (backslash)
185        processing, and also fixed erroneous offset values for syntax errors during
186        backslash processing.
188    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
189        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
191    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
192        caused an overrun.
194    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
195        something other than just ASCII characters) inside a group that had an
196        unlimited repeat caused a loop at compile time (while checking to see
197        whether the group could match an empty string).
199    20. Debugging a pattern containing \p or \P could cause a crash. For example,
200        [\P{Any}] did so. (Error in the code for printing property names.)
202    21. An orphan \E inside a character class could cause a crash.
204    22. A repeated capturing bracket such as (A)? could cause a wild memory
205        reference during compilation.
207    23. There are several functions in pcre_compile() that scan along a compiled
208        expression for various reasons (e.g. to see if it's fixed length for look
209        behind). There were bugs in these functions when a repeated \p or \P was
210        present in the pattern. These operators have additional parameters compared
211        with \d, etc, and these were not being taken into account when moving along
212        the compiled data. Specifically:
214        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
215            length.
217        (b) An item such as \pL+ within a repeated group could cause crashes or
218            loops.
220        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
221            "reference to non-existent subpattern" error.
223        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
225    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
226        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
228    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
230    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
231        character were causing crashes (broken optimization).
233    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
234        \p or \P) caused a compile-time loop.
236    28. More problems have arisen in unanchored patterns when CRLF is a valid line
237        break. For example, the unstudied pattern [\r\n]A does not match the string
238        "\r\nA" because change 7.0/46 below moves the current point on by two
239        characters after failing to match at the start. However, the pattern \nA
240        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
241        the same is true. There doesn't seem any very clean way out of this, but
242        what I have chosen to do makes the common cases work: PCRE now takes note
243        of whether there can be an explicit match for \r or \n anywhere in the
244        pattern, and if so, 7.0/46 no longer applies. As part of this change,
245        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
246        pattern has explicit CR or LF references.
248    29. Added (*CR) etc for changing newline setting at start of pattern.
251    Version 7.2 19-Jun-07
252    ---------------------
254     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
255        which is apparently normally available under Windows.
257     2. Re-jig the pcregrep tests with different newline settings in an attempt
258        to make them independent of the local environment's newline setting.
260     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
262     4. Some of the "internals" tests were previously cut out when the link size
263        was not 2, because the output contained actual offsets. The recent new
264        "Z" feature of pcretest means that these can be cut out, making the tests
265        usable with all link sizes.
267     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
268        stack recursion. This gives a massive performance boost under BSD, but just
269        a small improvement under Linux. However, it saves one field in the frame
270        in all cases.
272     6. Added more features from the forthcoming Perl 5.10:
274        (a) (?-n) (where n is a string of digits) is a relative subroutine or
275            recursion call. It refers to the nth most recently opened parentheses.
277        (b) (?+n) is also a relative subroutine call; it refers to the nth next
278            to be opened parentheses.
280        (c) Conditions that refer to capturing parentheses can be specified
281            relatively, for example, (?(-2)... or (?(+3)...
283        (d) \K resets the start of the current match so that everything before
284            is not part of it.
286        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
288        (f) \g{name} is another synonym - part of Perl 5.10's unification of
289            reference syntax.
291        (g) (?| introduces a group in which the numbering of parentheses in each
292            alternative starts with the same number.
294        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
296     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
299     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
300        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
301        for detecting groups that can match an empty string.
303     9. A pattern with a very large number of alternatives (more than several
304        hundred) was running out of internal workspace during the pre-compile
305        phase, where pcre_compile() figures out how much memory will be needed. A
306        bit of new cunning has reduced the workspace needed for groups with
307        alternatives. The 1000-alternative test pattern now uses 12 bytes of
308        workspace instead of running out of the 4096 that are available.
310    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
312    11. Applied patch from Google to remove an optimization that didn't quite work.
313        The report of the bug said:
315          pcrecpp::RE("a*").FullMatch("aaa") matches, while
316          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
317          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
319    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
320        it matched the wrong number of bytes.
323    Version 7.1 24-Apr-07
324    ---------------------
326     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
327        that is more "standard", making use of automake and other Autotools. There
328        is some re-arrangement of the files and adjustment of comments consequent
329        on this.
331     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
332        for recursive directory scanning broke on some systems because the files
333        are not scanned in any specific order and on different systems the order
334        was different. A call to "sort" has been inserted into RunGrepTest for the
335        approprate test as a short-term fix. In the longer term there may be an
336        alternative.
338     3. I had an email from Eric Raymond about problems translating some of PCRE's
339        man pages to HTML (despite the fact that I distribute HTML pages, some
340        people do their own conversions for various reasons). The problems
341        concerned the use of low-level troff macros .br and .in. I have therefore
342        removed all such uses from the man pages (some were redundant, some could
343        be replaced by .nf/.fi pairs). The 132html script that I use to generate
344        HTML has been updated to handle .nf/.fi and to complain if it encounters
345        .br or .in.
347     4. Updated comments in configure.ac that get placed in config.h.in and also
348        arranged for config.h to be included in the distribution, with the name
349        config.h.generic, for the benefit of those who have to compile without
350        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
352     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
353        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
354        makevp.bat for the current PCRE, using the additional files
355        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
357     6. A Windows user reported a minor discrepancy with test 2, which turned out
358        to be caused by a trailing space on an input line that had got lost in his
359        copy. The trailing space was an accident, so I've just removed it.
361     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
362        that is needed.
364     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
365        as "const" (a) because they are and (b) because it helps the PHP
366        maintainers who have recently made a script to detect big data structures
367        in the php code that should be moved to the .rodata section. I remembered
368        to update Builducptable as well, so it won't revert if ucptable.h is ever
369        re-created.
371     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
372        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
373        order to be able to cut out the UTF-8 tables in the latter when UTF-8
374        support is not required. This saves 1.5-2K of code, which is important in
375        some applications.
377        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
378        so as not to refer to the tables, even though these functions will never be
379        called when UTF-8 support is disabled. Otherwise there are problems with a
380        shared library.
382    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
384        (a) It was defining its arguments as char * instead of void *.
386        (b) It was assuming that all moves were upwards in memory; this was true
387            a long time ago when I wrote it, but is no longer the case.
389        The emulated memove() is provided for those environments that have neither
390        memmove() nor bcopy(). I didn't think anyone used it these days, but that
391        is clearly not the case, as these two bugs were recently reported.
393    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
394        and Detrail to create the HTML documentation, the .txt form of the man
395        pages, and it removes trailing spaces from listed files. It also creates
396        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
397        case, it wraps all the #defines with #ifndefs. This script should be run
398        before "make dist".
400    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
401        with Unicode property support.
403        (a) For a maximizing quantifier, if the two different cases of the
404            character were of different lengths in their UTF-8 codings (there are
405            some cases like this - I found 11), and the matching function had to
406            back up over a mixture of the two cases, it incorrectly assumed they
407            were both the same length.
409        (b) When PCRE was configured to use the heap rather than the stack for
410            recursion during matching, it was not correctly preserving the data for
411            the other case of a UTF-8 character when checking ahead for a match
412            while processing a minimizing repeat. If the check also involved
413            matching a wide character, but failed, corruption could cause an
414            erroneous result when trying to check for a repeat of the original
415            character.
417    13. Some tidying changes to the testing mechanism:
419        (a) The RunTest script now detects the internal link size and whether there
420            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
421            values substituted by "configure". (The RunGrepTest script already did
422            this for UTF-8.) The configure.ac script no longer substitutes the
423            relevant variables.
425        (b) The debugging options /B and /D in pcretest show the compiled bytecode
426            with length and offset values. This means that the output is different
427            for different internal link sizes. Test 2 is skipped for link sizes
428            other than 2 because of this, bypassing the problem. Unfortunately,
429            there was also a test in test 3 (the locale tests) that used /B and
430            failed for link sizes other than 2. Rather than cut the whole test out,
431            I have added a new /Z option to pcretest that replaces the length and
432            offset values with spaces. This is now used to make test 3 independent
433            of link size. (Test 2 will be tidied up later.)
435    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
436        segmentation fault instead of returning the appropriate error message.
438    15. In multiline mode when the newline sequence was set to "any", the pattern
439        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
440        This doesn't seem right; it now treats the CRLF combination as the line
441        ending, and so does not match in that case. It's only a pattern such as ^$
442        that would hit this one: something like ^ABC$ would have failed after \r
443        and then tried again after \r\n.
445    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
446        in an attempt to make files that differ only in their line terminators
447        compare equal. This works on Linux.
449    17. Under certain error circumstances pcregrep might try to free random memory
450        as it exited. This is now fixed, thanks to valgrind.
452    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
453        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
454        was because its rules for how to advance for /g after matching an empty
455        string at the end of a line did not allow for this case. They now check for
456        it specially.
458    20. pcretest is supposed to handle patterns and data of any length, by
459        extending its buffers when necessary. It was getting this wrong when the
460        buffer for a data line had to be extended.
462    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
463        CRLF as a newline sequence.
465    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
466        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
467        I have nevertheless tidied it up.
469    23. Added some casts to kill warnings from HP-UX ia64 compiler.
471    24. Added a man page for pcre-config.
474    Version 7.0 19-Dec-06
475    ---------------------
477     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
478        moving to gcc 4.1.1.
480     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
481        sys/time.h, which is documented as needed for this function. It doesn't
482        seem to matter on Linux, but it showed up on some releases of OS X.
484     3. It seems that there are systems where bytes whose values are greater than
485        127 match isprint() in the "C" locale. The "C" locale should be the
486        default when a C program starts up. In most systems, only ASCII printing
487        characters match isprint(). This difference caused the output from pcretest
488        to vary, making some of the tests fail. I have changed pcretest so that:
490        (a) When it is outputting text in the compiled version of a pattern, bytes
491            other than 32-126 are always shown as hex escapes.
493        (b) When it is outputting text that is a matched part of a subject string,
494            it does the same, unless a different locale has been set for the match
495            (using the /L modifier). In this case, it uses isprint() to decide.
497     4. Fixed a major bug that caused incorrect computation of the amount of memory
498        required for a compiled pattern when options that changed within the
499        pattern affected the logic of the preliminary scan that determines the
500        length. The relevant options are -x, and -i in UTF-8 mode. The result was
501        that the computed length was too small. The symptoms of this bug were
502        either the PCRE error "internal error: code overflow" from pcre_compile(),
503        or a glibc crash with a message such as "pcretest: free(): invalid next
504        size (fast)". Examples of patterns that provoked this bug (shown in
505        pcretest format) are:
507          /(?-x: )/x
508          /(?x)(?-x: \s*#\s*)/
509          /((?i)[\x{c0}])/8
510          /(?i:[\x{c0}])/8
512        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
513        is now done differently.
515     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
516        wrapper classes; (b) implement a new function in the C++ scanner that is
517        more efficient than the old way of doing things because it avoids levels of
518        recursion in the regex matching; (c) add a paragraph to the documentation
519        for the FullMatch() function.
521     6. The escape sequence \n was being treated as whatever was defined as
522        "newline". Not only was this contrary to the documentation, which states
523        that \n is character 10 (hex 0A), but it also went horribly wrong when
524        "newline" was defined as CRLF. This has been fixed.
526     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
527        was being set to -1 for the "end of line" case (supposedly a value that no
528        character can have). Though this value is never used (the check for end of
529        line is "zero bytes in current character"), it caused compiler complaints.
530        I've changed it to 0xffffffff.
532     8. In pcre_version.c, the version string was being built by a sequence of
533        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
534        string (as it is for production releases) called a macro with an empty
535        argument. The C standard says the result of this is undefined. The gcc
536        compiler treats it as an empty string (which was what was wanted) but it is
537        reported that Visual C gives an error. The source has been hacked around to
538        avoid this problem.
540     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
541        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
542        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
543        of them did).
545    10. Originally, pcretest opened its input and output without "b"; then I was
546        told that "b" was needed in some environments, so it was added for release
547        5.0 to both the input and output. (It makes no difference on Unix-like
548        systems.) Later I was told that it is wrong for the input on Windows. I've
549        now abstracted the modes into two macros, to make it easier to fiddle with
550        them, and removed "b" from the input mode under Windows.
552    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
554    12. Added -help and --help to pcretest as an official way of being reminded
555        of the options.
557    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
558        and pcrecpp.cc because they annoy compilers at high warning levels.
560    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
562    15. Fixed an occurrence of == in configure.ac that should have been = (shell
563        scripts are not C programs :-) and which was not noticed because it works
564        on Linux.
566    16. pcretest is supposed to handle any length of pattern and data line (as one
567        line or as a continued sequence of lines) by extending its input buffer if
568        necessary. This feature was broken for very long pattern lines, leading to
569        a string of junk being passed to pcre_compile() if the pattern was longer
570        than about 50K.
572    17. I have done a major re-factoring of the way pcre_compile() computes the
573        amount of memory needed for a compiled pattern. Previously, there was code
574        that made a preliminary scan of the pattern in order to do this. That was
575        OK when PCRE was new, but as the facilities have expanded, it has become
576        harder and harder to keep it in step with the real compile phase, and there
577        have been a number of bugs (see for example, 4 above). I have now found a
578        cunning way of running the real compile function in a "fake" mode that
579        enables it to compute how much memory it would need, while actually only
580        ever using a few hundred bytes of working memory and without too many
581        tests of the mode. This should make future maintenance and development
582        easier. A side effect of this work is that the limit of 200 on the nesting
583        depth of parentheses has been removed (though this was never a serious
584        limitation, I suspect). However, there is a downside: pcre_compile() now
585        runs more slowly than before (30% or more, depending on the pattern). I
586        hope this isn't a big issue. There is no effect on runtime performance.
588    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
589        newline (only possible for the last line of a file) and it was a
590        pattern that set a locale (followed by /Lsomething), pcretest crashed.
592    19. Added additional timing features to pcretest. (1) The -tm option now times
593        matching only, not compiling. (2) Both -t and -tm can be followed, as a
594        separate command line item, by a number that specifies the number of
595        repeats to use when timing. The default is 50000; this gives better
596        precision, but takes uncomfortably long for very large patterns.
598    20. Extended pcre_study() to be more clever in cases where a branch of a
599        subpattern has no definite first character. For example, (a*|b*)[cd] would
600        previously give no result from pcre_study(). Now it recognizes that the
601        first character must be a, b, c, or d.
603    21. There was an incorrect error "recursive call could loop indefinitely" if
604        a subpattern (or the entire pattern) that was being tested for matching an
605        empty string contained only one non-empty item after a nested subpattern.
606        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
607        incorrectly, because the \d was being skipped in the check.
609    22. The pcretest program now has a new pattern option /B and a command line
610        option -b, which is equivalent to adding /B to every pattern. This causes
611        it to show the compiled bytecode, without the additional information that
612        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
613        is the same as /B/I).
615    23. A new optimization is now able automatically to treat some sequences such
616        as a*b as a*+b. More specifically, if something simple (such as a character
617        or a simple class like \d) has an unlimited quantifier, and is followed by
618        something that cannot possibly match the quantified thing, the quantifier
619        is automatically "possessified".
621    24. A recursive reference to a subpattern whose number was greater than 39
622        went wrong under certain circumstances in UTF-8 mode. This bug could also
623        have affected the operation of pcre_study().
625    25. Realized that a little bit of performance could be had by replacing
626        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
628    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
630    27. Possessive quantifiers such as a++ were previously implemented by turning
631        them into atomic groups such as ($>a+). Now they have their own opcodes,
632        which improves performance. This includes the automatically created ones
633        from 23 above.
635    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
636        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
637        the first matched character to be a colon. This applied both to named and
638        numbered groups.
640    29. The ucpinternal.h header file was missing its idempotency #ifdef.
642    30. I was sent a "project" file called libpcre.a.dev which I understand makes
643        building PCRE on Windows easier, so I have included it in the distribution.
645    31. There is now a check in pcretest against a ridiculously large number being
646        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
647        loop, the loop is abandoned.
649    32. Forward references to subpatterns in conditions such as (?(2)...) where
650        subpattern 2 is defined later cause pcre_compile() to search forwards in
651        the pattern for the relevant set of parentheses. This search went wrong
652        when there were unescaped parentheses in a character class, parentheses
653        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
655    33. "Subroutine" calls and backreferences were previously restricted to
656        referencing subpatterns earlier in the regex. This restriction has now
657        been removed.
659    34. Added a number of extra features that are going to be in Perl 5.10. On the
660        whole, these are just syntactic alternatives for features that PCRE had
661        previously implemented using the Python syntax or my own invention. The
662        other formats are all retained for compatibility.
664        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
665            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
666            also .NET compatible.
668        (b) A recursion or subroutine call to a named group can now be defined as
669            (?&name) as well as (?P>name).
671        (c) A backreference to a named group can now be defined as \k<name> or
672            \k'name' as well as (?P=name). The new forms, as well as being in Perl
673            5.10, are also .NET compatible.
675        (d) A conditional reference to a named group can now use the syntax
676            (?(<name>) or (?('name') as well as (?(name).
678        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
679            groups (named and numbered) that are never evaluated inline, but can be
680            called as "subroutines" from elsewhere. In effect, the DEFINE condition
681            is always false. There may be only one alternative in such a group.
683        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
684            as the simple (?(R). The condition is true only if the most recent
685            recursion is that of the given number or name. It does not search out
686            through the entire recursion stack.
688        (g) The escape \gN or \g{N} has been added, where N is a positive or
689            negative number, specifying an absolute or relative reference.
691    35. Tidied to get rid of some further signed/unsigned compiler warnings and
692        some "unreachable code" warnings.
694    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
695        things, this adds five new scripts.
697    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
698        There were also incompatibilities regarding the handling of \Q..\E inside
699        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
700        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
702    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
703        matches an empty string, and forcibly breaks the loop. There were bugs in
704        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
705        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
706        separate and independent bugs (that affected different cases) have been
707        fixed.
709    39. Refactored the code to abolish the use of different opcodes for small
710        capturing bracket numbers. This is a tidy that I avoided doing when I
711        removed the limit on the number of capturing brackets for 3.5 back in 2001.
712        The new approach is not only tidier, it makes it possible to reduce the
713        memory needed to fix the previous bug (38).
715    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
716        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
717        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
718        mode.
720    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
721        report.
723    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
724        copy construction and assignment in the C++ wrapper.
726    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
727        couple of bugs that could have given wrong results in the "--newline=crlf"
728        case.
730    44. Added a number of casts and did some reorganization of signed/unsigned int
731        variables following suggestions from Dair Grant. Also renamed the variable
732        "this" as "item" because it is a C++ keyword.
734    45. Arranged for dftables to add
736          #include "pcre_internal.h"
738        to pcre_chartables.c because without it, gcc 4.x may remove the array
739        definition from the final binary if PCRE is built into a static library and
740        dead code stripping is activated.
742    46. For an unanchored pattern, if a match attempt fails at the start of a
743        newline sequence, and the newline setting is CRLF or ANY, and the next two
744        characters are CRLF, advance by two characters instead of one.
747    Version 6.7 04-Jul-06
748    ---------------------
750     1. In order to handle tests when input lines are enormously long, pcretest has
751        been re-factored so that it automatically extends its buffers when
752        necessary. The code is crude, but this _is_ just a test program. The
753        default size has been increased from 32K to 50K.
755     2. The code in pcre_study() was using the value of the re argument before
756        testing it for NULL. (Of course, in any sensible call of the function, it
757        won't be NULL.)
759     3. The memmove() emulation function in pcre_internal.h, which is used on
760        systems that lack both memmove() and bcopy() - that is, hardly ever -
761        was missing a "static" storage class specifier.
763     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
764        containing an extended class (one that cannot be represented by a bitmap
765        because it contains high-valued characters or Unicode property items, e.g.
766        [\pZ]). Almost always one would set UTF-8 mode when processing such a
767        pattern, but PCRE should not loop if you do not (it no longer does).
768        [Detail: two cases were found: (a) a repeated subpattern containing an
769        extended class; (b) a recursive reference to a subpattern that followed a
770        previous extended class. It wasn't skipping over the extended class
771        correctly when UTF-8 mode was not set.]
773     5. A negated single-character class was not being recognized as fixed-length
774        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
775        compile error "lookbehind assertion is not fixed length".
777     6. The RunPerlTest auxiliary script was showing an unexpected difference
778        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
779        write a Perl script that can interpret lines of an input file either as
780        byte characters or as UTF-8, which is what "perltest" was being required to
781        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
782        can't do is switch easily at run time between having the "use utf8;" pragma
783        or not. In the end, I fudged it by using the RunPerlTest script to insert
784        "use utf8;" explicitly for the UTF-8 tests.
786     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
787        the end of the subject string, contrary to the documentation and to what
788        Perl does. This was true of both matching functions. Now it matches only at
789        the start of the subject and immediately after *internal* newlines.
791     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
792        a pointer to an int instead of a pointer to an unsigned long int. This
793        caused problems on 64-bit systems.
795     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
796        instance of the 'standard' template library not being so standard".
798    10. There was no check on the number of named subpatterns nor the maximum
799        length of a subpattern name. The product of these values is used to compute
800        the size of the memory block for a compiled pattern. By supplying a very
801        long subpattern name and a large number of named subpatterns, the size
802        computation could be caused to overflow. This is now prevented by limiting
803        the length of names to 32 characters, and the number of named subpatterns
804        to 10,000.
806    11. Subpatterns that are repeated with specific counts have to be replicated in
807        the compiled pattern. The size of memory for this was computed from the
808        length of the subpattern and the repeat count. The latter is limited to
809        65535, but there was no limit on the former, meaning that integer overflow
810        could in principle occur. The compiled length of a repeated subpattern is
811        now limited to 30,000 bytes in order to prevent this.
813    12. Added the optional facility to have named substrings with the same name.
815    13. Added the ability to use a named substring as a condition, using the
816        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
817        are numbers (not recommended). Forward references are permitted.
819    14. Added forward references in named backreferences (if you see what I mean).
821    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
822        pattern could run off the end of the subject. For example, the pattern
823        "(?s)(.{1,5})"8 did this with the subject "ab".
825    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
826        PCRE_CASELESS was set when matching characters that were quantified with ?
827        or *.
829    17. A character class other than a single negated character that had a minimum
830        but no maximum quantifier - for example [ab]{6,} - was not handled
831        correctly by pce_dfa_exec(). It would match only one character.
833    18. A valid (though odd) pattern that looked like a POSIX character
834        class but used an invalid character after [ (for example [[,abc,]]) caused
835        pcre_compile() to give the error "Failed: internal error: code overflow" or
836        in some cases to crash with a glibc free() error. This could even happen if
837        the pattern terminated after [[ but there just happened to be a sequence of
838        letters, a binary zero, and a closing ] in the memory that followed.
840    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
841        over the years. Originally (before any Unicode support), just the bottom 8
842        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
843        output from "man perlunicode" includes this:
845          The regular expression compiler produces polymorphic opcodes.  That
846          is, the pattern adapts to the data and automatically switches to
847          the Unicode character scheme when presented with Unicode data--or
848          instead uses a traditional byte scheme when presented with byte
849          data.
851        Sadly, a wide octal escape does not cause a switch, and in a string with
852        no other multibyte characters, these octal escapes are treated as before.
853        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
854        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
855        Unicode string.
857        I have not perpetrated such confusion in PCRE. Up till now, it took just
858        the bottom 8 bits, as in old Perl. I have now made octal escapes with
859        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
860        translate to the appropriate multibyte character.
862    29. Applied some refactoring to reduce the number of warnings from Microsoft
863        and Borland compilers. This has included removing the fudge introduced
864        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
865        a warning about an unused variable.
867    21. PCRE has not included VT (character 0x0b) in the set of whitespace
868        characters since release 4.0, because Perl (from release 5.004) does not.
869        [Or at least, is documented not to: some releases seem to be in conflict
870        with the documentation.] However, when a pattern was studied with
871        pcre_study() and all its branches started with \s, PCRE still included VT
872        as a possible starting character. Of course, this did no harm; it just
873        caused an unnecessary match attempt.
875    22. Removed a now-redundant internal flag bit that recorded the fact that case
876        dependency changed within the pattern. This was once needed for "required
877        byte" processing, but is no longer used. This recovers a now-scarce options
878        bit. Also moved the least significant internal flag bit to the most-
879        significant bit of the word, which was not previously used (hangover from
880        the days when it was an int rather than a uint) to free up another bit for
881        the future.
883    23. Added support for CRLF line endings as well as CR and LF. As well as the
884        default being selectable at build time, it can now be changed at runtime
885        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
886        specify that it is scanning data with non-default line endings.
888    24. Changed the definition of CXXLINK to make it agree with the definition of
889        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
891    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
892        recursions. This makes a big different to stack usage for some patterns.
894    26. If a subpattern containing a named recursion or subroutine reference such
895        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
896        the space required for the compiled pattern went wrong and gave too small a
897        value. Depending on the environment, this could lead to "Failed: internal
898        error: code overflow at offset 49" or "glibc detected double free or
899        corruption" errors.
901    27. Applied patches from Google (a) to support the new newline modes and (b) to
902        advance over multibyte UTF-8 characters in GlobalReplace.
904    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
905        difference for some implementation of PCRE in some Windows version.
907    29. Added some extra testing facilities to pcretest:
909        \q<number>   in a data line sets the "match limit" value
910        \Q<number>   in a data line sets the "match recursion limt" value
911        -S <number>  sets the stack size, where <number> is in megabytes
913        The -S option isn't available for Windows.
916    Version 6.6 06-Feb-06
917    ---------------------
919     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
920        in pcreposix.h. I have copied the definition from pcre.h.
922     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
923        because pcre.h is no longer a built file.
925     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
926        not normally included in the compiled code.
929    Version 6.5 01-Feb-06
930    ---------------------
932     1. When using the partial match feature with pcre_dfa_exec(), it was not
933        anchoring the second and subsequent partial matches at the new starting
934        point. This could lead to incorrect results. For example, with the pattern
935        /1234/, partially matching against "123" and then "a4" gave a match.
937     2. Changes to pcregrep:
939        (a) All non-match returns from pcre_exec() were being treated as failures
940            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
941            error message is output. Some extra information is given for the
942            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
943            probably the only errors that are likely to be caused by users (by
944            specifying a regex that has nested indefinite repeats, for instance).
945            If there are more than 20 of these errors, pcregrep is abandoned.
947        (b) A binary zero was treated as data while matching, but terminated the
948            output line if it was written out. This has been fixed: binary zeroes
949            are now no different to any other data bytes.
951        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
952            used to set a locale for matching. The --locale=xxxx long option has
953            been added (no short equivalent) to specify a locale explicitly on the
954            pcregrep command, overriding the environment variables.
956        (d) When -B was used with -n, some line numbers in the output were one less
957            than they should have been.
959        (e) Added the -o (--only-matching) option.
961        (f) If -A or -C was used with -c (count only), some lines of context were
962            accidentally printed for the final match.
964        (g) Added the -H (--with-filename) option.
966        (h) The combination of options -rh failed to suppress file names for files
967            that were found from directory arguments.
969        (i) Added the -D (--devices) and -d (--directories) options.
971        (j) Added the -F (--fixed-strings) option.
973        (k) Allow "-" to be used as a file name for -f as well as for a data file.
975        (l) Added the --colo(u)r option.
977        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
978            is not present by default.
980     3. A nasty bug was discovered in the handling of recursive patterns, that is,
981        items such as (?R) or (?1), when the recursion could match a number of
982        alternatives. If it matched one of the alternatives, but subsequently,
983        outside the recursion, there was a failure, the code tried to back up into
984        the recursion. However, because of the way PCRE is implemented, this is not
985        possible, and the result was an incorrect result from the match.
987        In order to prevent this happening, the specification of recursion has
988        been changed so that all such subpatterns are automatically treated as
989        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
991     4. I had overlooked the fact that, in some locales, there are characters for
992        which isalpha() is true but neither isupper() nor islower() are true. In
993        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
994        and ordfeminine) are like this. This affected the treatment of \w and \W
995        when they appeared in character classes, but not when they appeared outside
996        a character class. The bit map for "word" characters is now created
997        separately from the results of isalnum() instead of just taking it from the
998        upper, lower, and digit maps. (Plus the underscore character, of course.)
1000     5. The above bug also affected the handling of POSIX character classes such as
1001        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1002        permanent tables. Instead, the bit maps for such a class were previously
1003        created as the appropriate unions of the upper, lower, and digit bitmaps.
1004        Now they are created by subtraction from the [[:word:]] class, which has
1005        its own bitmap.
1007     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1008        It is created by subtracting the vertical space characters (\x09, \x0a,
1009        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1010        subtraction was done in the overall bitmap for a character class, meaning
1011        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1012        be recognized. This bug has been fixed.
1014     7. Patches from the folks at Google:
1016          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1017          real life, but is still worth protecting against".
1019          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1020          regular expressions".
1022          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1023          have it.
1025          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1026          "configure" and the latter not, in order to fix a problem somebody had
1027          with compiling the Arg class on HP-UX.
1029          (e) Improve the error-handling of the C++ wrapper a little bit.
1031          (f) New tests for checking recursion limiting.
1033     8. The pcre_memmove() function, which is used only if the environment does not
1034        have a standard memmove() function (and is therefore rarely compiled),
1035        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1036        returning a result (though PCRE never actually uses the result).
1038     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1039        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1040        returned instead of calling malloc() with an overflowing number that would
1041        most likely cause subsequent chaos.
1043    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1045    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1046        with this option is matched, the nmatch and pmatch options of regexec() are
1047        ignored.
1049    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1050        provided in case anyone wants to the the POSIX interface with UTF-8
1051        strings.
1053    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1054        C++ linking (needed for some HP-UX environments).
1056    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1057        (unused parameter) and in the pcre_printint() function (omitted "default"
1058        switch label when the default is to do nothing).
1060    15. Added some code to make it possible, when PCRE is compiled as a C++
1061        library, to replace subject pointers for pcre_exec() with a smart pointer
1062        class, thus making it possible to process discontinuous strings.
1064    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1065        much the same function. They were added by different people who were trying
1066        to make PCRE easy to compile on non-Unix systems. It has been suggested
1067        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1068        for compiling on Windows systems. I have therefore replaced it with
1069        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1070        defaults to "extern" for C or "extern C" for C++, which works fine on
1071        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1072        SCOPE with something explicit in config.h. In addition:
1074        (a) pcreposix.h still had just "extern" instead of either of these macros;
1075            I have replaced it with PCRE_DATA_SCOPE.
1077        (b) Functions such as _pcre_xclass(), which are internal to the library,
1078            but external in the C sense, all had PCRE_EXPORT in their definitions.
1079            This is apparently wrong for the Windows case, so I have removed it.
1080            (It makes no difference on Unix-like systems.)
1082    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1083        of recursive calls to match(). This is different to MATCH_LIMIT because
1084        that limits the total number of calls to match(), not all of which increase
1085        the depth of recursion. Limiting the recursion depth limits the amount of
1086        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1087        when PCRE is compiled, and changed at run time. A patch from Google adds
1088        this functionality to the C++ interface.
1090    18. Changes to the handling of Unicode character properties:
1092        (a) Updated the table to Unicode 4.1.0.
1094        (b) Recognize characters that are not in the table as "Cn" (undefined).
1096        (c) I revised the way the table is implemented to a much improved format
1097            which includes recognition of ranges. It now supports the ranges that
1098            are defined in UnicodeData.txt, and it also amalgamates other
1099            characters into ranges. This has reduced the number of entries in the
1100            table from around 16,000 to around 3,000, thus reducing its size
1101            considerably. I realized I did not need to use a tree structure after
1102            all - a binary chop search is just as efficient. Having reduced the
1103            number of entries, I extended their size from 6 bytes to 8 bytes to
1104            allow for more data.
1106        (d) Added support for Unicode script names via properties such as \p{Han}.
1108    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1109        matching that character.
1111    20. When matching a repeated Unicode property with a minimum greater than zero,
1112        (for example \pL{2,}), PCRE could look past the end of the subject if it
1113        reached it while seeking the minimum number of characters. This could
1114        happen only if some of the characters were more than one byte long, because
1115        there is a check for at least the minimum number of bytes.
1117    21. Refactored the implementation of \p and \P so as to be more general, to
1118        allow for more different types of property in future. This has changed the
1119        compiled form incompatibly. Anybody with saved compiled patterns that use
1120        \p or \P will have to recompile them.
1122    22. Added "Any" and "L&" to the supported property types.
1124    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1125        but give a compile time error if the value is greater than 0xff.
1127    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1128        accidentally not being installed or uninstalled.
1130    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1131        made were to insert the current release number. This seemed silly, because
1132        it made things harder for people building PCRE on systems that don't run
1133        "configure". I have turned pcre.h into a distributed file, no longer built
1134        by "configure", with the version identification directly included. There is
1135        no longer a pcre.h.in file.
1137        However, this change necessitated a change to the pcre-config script as
1138        well. It is built from pcre-config.in, and one of the substitutions was the
1139        release number. I have updated configure.ac so that ./configure now finds
1140        the release number by grepping pcre.h.
1142    26. Added the ability to run the tests under valgrind.
1145    Version 6.4 05-Sep-05
1146    ---------------------
1148     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1149        "--" to be printed when multiple files were scanned, even when none of the
1150        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1151        consider it to be a bug, and have restored the previous behaviour.
1153     2. A couple of code tidies to get rid of compiler warnings.
1155     3. The pcretest program used to cheat by referring to symbols in the library
1156        whose names begin with _pcre_. These are internal symbols that are not
1157        really supposed to be visible externally, and in some environments it is
1158        possible to suppress them. The cheating is now confined to including
1159        certain files from the library's source, which is a bit cleaner.
1161     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1162        file's purpose clearer.
1164     5. Reorganized pcre_ucp_findchar().
1167    Version 6.3 15-Aug-05
1168    ---------------------
1170     1. The file libpcre.pc.in did not have general read permission in the tarball.
1172     2. There were some problems when building without C++ support:
1174        (a) If C++ support was not built, "make install" and "make test" still
1175            tried to test it.
1177        (b) There were problems when the value of CXX was explicitly set. Some
1178            changes have been made to try to fix these, and ...
1180        (c) --disable-cpp can now be used to explicitly disable C++ support.
1182        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1183            backslash in a target when C++ was disabled. This confuses some
1184            versions of "make", apparently. Using an intermediate variable solves
1185            this. (Same for CPP_LOBJ.)
1187     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1188        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1189        necessary on certain architectures.
1191     4. Added a setting of -export-symbols-regex to the link command to remove
1192        those symbols that are exported in the C sense, but actually are local
1193        within the library, and not documented. Their names all begin with
1194        "_pcre_". This is not a perfect job, because (a) we have to except some
1195        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1196        available (and never for static libraries). I have made a note to try to
1197        find a way round (a) in the future.
1200    Version 6.2 01-Aug-05
1201    ---------------------
1203     1. There was no test for integer overflow of quantifier values. A construction
1204        such as {1111111111111111} would give undefined results. What is worse, if
1205        a minimum quantifier for a parenthesized subpattern overflowed and became
1206        negative, the calculation of the memory size went wrong. This could have
1207        led to memory overwriting.
1209     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1211     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1212        operating environments where this matters.
1214     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1215        PCRE options from within the C++ wrapper.
1217     5. Named capturing subpatterns were not being correctly counted when a pattern
1218        was compiled. This caused two problems: (a) If there were more than 100
1219        such subpatterns, the calculation of the memory needed for the whole
1220        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1221        back references of the form \12, where the number was greater than 9, were
1222        not recognized as back references, even though there were sufficient
1223        previous subpatterns.
1225     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1226        versions of gcc, e.g. 2.95.4.
1229    Version 6.1 21-Jun-05
1230    ---------------------
1232     1. There was one reference to the variable "posix" in pcretest.c that was not
1233        surrounded by "#if !defined NOPOSIX".
1235     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1236        the cross-check on the old pcre_info() function, for the benefit of the
1237        cut-down version of PCRE that is currently imported into Exim.
1239     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1240        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1241        patterns that start (?i) but I don't think that matters. The use of (?i) is
1242        just an example; this all applies to the other options as well.
1244     4. Since libtool seems to echo the compile commands it is issuing, the output
1245        from "make" can be reduced a bit by putting "@" in front of each libtool
1246        compile command.
1248     5. Patch from the folks at Google for configure.in to be a bit more thorough
1249        in checking for a suitable C++ installation before trying to compile the
1250        C++ stuff. This should fix a reported problem when a compiler was present,
1251        but no suitable headers.
1253     6. The man pages all had just "PCRE" as their title. I have changed them to
1254        be the relevant file name. I have also arranged that these names are
1255        retained in the file doc/pcre.txt, which is a concatenation in text format
1256        of all the man pages except the little individual ones for each function.
1258     7. The NON-UNIX-USE file had not been updated for the different set of source
1259        files that come with release 6. I also added a few comments about the C++
1260        wrapper.
1263    Version 6.0 07-Jun-05
1264    ---------------------
1266     1. Some minor internal re-organization to help with my DFA experiments.
1268     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1269        didn't matter for the library itself when fully configured, but did matter
1270        when compiling without UCP support, or within Exim, where the ucp files are
1271        not imported.
1273     3. Refactoring of the library code to split up the various functions into
1274        different source modules. The addition of the new DFA matching code (see
1275        below) to a single monolithic source would have made it really too
1276        unwieldy, quite apart from causing all the code to be include in a
1277        statically linked application, when only some functions are used. This is
1278        relevant even without the DFA addition now that patterns can be compiled in
1279        one application and matched in another.
1281        The downside of splitting up is that there have to be some external
1282        functions and data tables that are used internally in different modules of
1283        the library but which are not part of the API. These have all had their
1284        names changed to start with "_pcre_" so that they are unlikely to clash
1285        with other external names.
1287     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1288        a different (DFA) algorithm. Although it is slower than the original
1289        function, it does have some advantages for certain types of matching
1290        problem.
1292     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1293        including restarting after a partial match.
1295     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1296        defined when compiling for Windows was sent to me. I have put it into the
1297        code, though I have no means of testing or verifying it.
1299     7. Added the pcre_refcount() auxiliary function.
1301     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1302        match before or at the first newline in the subject string. In pcretest,
1303        the /f option on a pattern can be used to set this.
1305     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1306        would behave wrongly. This has been present in PCRE since release 4.0.
1308    10. A number of changes to the pcregrep command:
1310        (a) Refactored how -x works; insert ^(...)$ instead of setting
1311            PCRE_ANCHORED and checking the length, in preparation for adding
1312            something similar for -w.
1314        (b) Added the -w (match as a word) option.
1316        (c) Refactored the way lines are read and buffered so as to have more
1317            than one at a time available.
1319        (d) Implemented a pcregrep test script.
1321        (e) Added the -M (multiline match) option. This allows patterns to match
1322            over several lines of the subject. The buffering ensures that at least
1323            8K, or the rest of the document (whichever is the shorter) is available
1324            for matching (and similarly the previous 8K for lookbehind assertions).
1326        (f) Changed the --help output so that it now says
1328              -w, --word-regex(p)
1330            instead of two lines, one with "regex" and the other with "regexp"
1331            because that confused at least one person since the short forms are the
1332            same. (This required a bit of code, as the output is generated
1333            automatically from a table. It wasn't just a text change.)
1335        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1336            option but starts with a hyphen. Could be a pattern or a path name
1337            starting with a hyphen, for instance.
1339        (h) "-" can be given as a file name to represent stdin.
1341        (i) When file names are being printed, "(standard input)" is used for
1342            the standard input, for compatibility with GNU grep. Previously
1343            "<stdin>" was used.
1345        (j) The option --label=xxx can be used to supply a name to be used for
1346            stdin when file names are being printed. There is no short form.
1348        (k) Re-factored the options decoding logic because we are going to add
1349            two more options that take data. Such options can now be given in four
1350            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1352        (l) Added the -A, -B, and -C options for requesting that lines of context
1353            around matches be printed.
1355        (m) Added the -L option to print the names of files that do not contain
1356            any matching lines, that is, the complement of -l.
1358        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1359            continue to scan other files.
1361        (o) The -s option was incorrectly implemented. For compatibility with other
1362            greps, it now suppresses the error message for a non-existent or non-
1363            accessible file (but not the return code). There is a new option called
1364            -q that suppresses the output of matching lines, which was what -s was
1365            previously doing.
1367        (p) Added --include and --exclude options to specify files for inclusion
1368            and exclusion when recursing.
1370    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1371        Hopefully, it now does.
1373    12. Missing cast in pcre_study().
1375    13. Added an "uninstall" target to the makefile.
1377    14. Replaced "extern" in the function prototypes in Makefile.in with
1378        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1379        world, but is set differently for Windows.
1381    15. Added a second compiling function called pcre_compile2(). The only
1382        difference is that it has an extra argument, which is a pointer to an
1383        integer error code. When there is a compile-time failure, this is set
1384        non-zero, in addition to the error test pointer being set to point to an
1385        error message. The new argument may be NULL if no error number is required
1386        (but then you may as well call pcre_compile(), which is now just a
1387        wrapper). This facility is provided because some applications need a
1388        numeric error indication, but it has also enabled me to tidy up the way
1389        compile-time errors are handled in the POSIX wrapper.
1391    16. Added VPATH=.libs to the makefile; this should help when building with one
1392        prefix path and installing with another. (Or so I'm told by someone who
1393        knows more about this stuff than I do.)
1395    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1396        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1397        match everything, including newlines. This is not POSIX-compatible, but
1398        somebody wanted the feature. From pcretest it can be activated by using
1399        both the P and the s flags.
1401    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1403    19. libpcre.pc was being incorrectly installed as executable.
1405    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1406        it now also looks for '\r' so that it will work unmodified on Windows.
1408    21. Added Google's contributed C++ wrapper to the distribution.
1410    22. Added some untidy missing memory free() calls in pcretest, to keep
1411        Electric Fence happy when testing.
1415    Version 5.0 13-Sep-04
1416    ---------------------
1418     1. Internal change: literal characters are no longer packed up into items
1419        containing multiple characters in a single byte-string. Each character
1420        is now matched using a separate opcode. However, there may be more than one
1421        byte in the character in UTF-8 mode.
1423     2. The pcre_callout_block structure has two new fields: pattern_position and
1424        next_item_length. These contain the offset in the pattern to the next match
1425        item, and its length, respectively.
1427     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1428        insertion of callouts before each pattern item. Added the /C option to
1429        pcretest to make use of this.
1431     4. On the advice of a Windows user, the lines
1433          #if defined(_WIN32) || defined(WIN32)
1434          _setmode( _fileno( stdout ), 0x8000 );
1435          #endif  /* defined(_WIN32) || defined(WIN32) */
1437        have been added to the source of pcretest. This apparently does useful
1438        magic in relation to line terminators.
1440     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1441        for the benefit of those environments where the "b" makes a difference.
1443     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1444        to know about it. I have put a hack into configure.in that adds in code
1445        to set GCC=yes if CC=icc. This seems to end up at a point in the
1446        generated configure script that is early enough to affect the setting of
1447        compiler options, which is what is needed, but I have no means of testing
1448        whether it really works. (The user who reported this had patched the
1449        generated configure script, which of course I cannot do.)
1451        LATER: After change 22 below (new libtool files), the configure script
1452        seems to know about icc (and also ecc). Therefore, I have commented out
1453        this hack in configure.in.
1455     7. Added support for pkg-config (2 patches were sent in).
1457     8. Negated POSIX character classes that used a combination of internal tables
1458        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1459        [[:^ascii]]. Typically, they would match almost any characters. The other
1460        POSIX classes were not broken in this way.
1462     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1463        to find the match, as PCRE was deluded into thinking that the match had to
1464        start at the start point or following a newline. The same bug applied to
1465        patterns with negative forward assertions or any backward assertions
1466        preceding ".*" at the start, unless the pattern required a fixed first
1467        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1469    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1470        starting at the last subject character, bytes beyond the end of the subject
1471        string were read.
1473    11. Renamed the variable "class" as "classbits" to make life easier for C++
1474        users. (Previously there was a macro definition, but it apparently wasn't
1475        enough.)
1477    12. Added the new field "tables" to the extra data so that tables can be passed
1478        in at exec time, or the internal tables can be re-selected. This allows
1479        a compiled regex to be saved and re-used at a later time by a different
1480        program that might have everything at different addresses.
1482    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1483        -R library as well as a -L library.
1485    14. The debugging options of pcretest (-d on the command line or D on a
1486        pattern) showed incorrect output for anything following an extended class
1487        that contained multibyte characters and which was followed by a quantifier.
1489    15. Added optional support for general category Unicode character properties
1490        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1491        support. It adds about 90K to the size of the library. The meanings of the
1492        inbuilt class escapes such as \d and \s have NOT been changed.
1494    16. Updated pcredemo.c to include calls to free() to release the memory for the
1495        compiled pattern.
1497    17. The generated file chartables.c was being created in the source directory
1498        instead of in the building directory. This caused the build to fail if the
1499        source directory was different from the building directory, and was
1500        read-only.
1502    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1503        file. No doubt somebody will tell me if they don't make sense... Also added
1504        Dan Mooney's comments about building on OpenVMS.
1506    19. Added support for partial matching via the PCRE_PARTIAL option for
1507        pcre_exec() and the \P data escape in pcretest.
1509    20. Extended pcretest with 3 new pattern features:
1511        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1512              write the compiled pattern to the file whose name is "rest-of-line".
1513              This is a straight binary dump of the data, with the saved pointer to
1514              the character tables forced to be NULL. The study data, if any, is
1515              written too. After writing, pcretest reads a new pattern.
1517        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1518              compiled pattern from the given file. There must not be any
1519              occurrences of "<" in the file name (pretty unlikely); if there are,
1520              pcretest will instead treat the initial "<" as a pattern delimiter.
1521              After reading in the pattern, pcretest goes on to read data lines as
1522              usual.
1524        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1525              and 16-bit fields in a compiled pattern, to simulate a pattern that
1526              was compiled on a host of opposite endianness.
1528    21. The pcre-exec() function can now cope with patterns that were compiled on
1529        hosts of opposite endianness, with this restriction:
1531          As for any compiled expression that is saved and used later, the tables
1532          pointer field cannot be preserved; the extra_data field in the arguments
1533          to pcre_exec() should be used to pass in a tables address if a value
1534          other than the default internal tables were used at compile time.
1536    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1537        now diagnosed as an error. Previously, most of the time, a negative number
1538        would have been treated as zero, but if in addition "ovector" was passed as
1539        NULL, a crash could occur.
1541    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1542        new versions from the libtool 1.5 distribution (the last one is a copy of
1543        a file called libtool.m4). This seems to have fixed the need to patch
1544        "configure" to support Darwin 1.3 (which I used to do). However, I still
1545        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1546        workstation).
1548    24. Changed the PCRE licence to be the more standard "BSD" licence.
1551    Version 4.5 01-Dec-03
1552    ---------------------
1554     1. There has been some re-arrangement of the code for the match() function so
1555        that it can be compiled in a version that does not call itself recursively.
1556        Instead, it keeps those local variables that need separate instances for
1557        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1558        needs to "recurse". Keeping track of where control must go is done by means
1559        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1560        hide most of the details from the main code, and operates only if
1561        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1562        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1563        operating.
1565        To make it easier for callers to provide specially tailored get/free
1566        functions for this usage, two new functions, pcre_stack_malloc, and
1567        pcre_stack_free, are used. They are always called in strict stacking order,
1568        and the size of block requested is always the same.
1570        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1571        PCRE has been compiled to use the stack or the heap for recursion. The
1572        -C option of pcretest uses this to show which version is compiled.
1574        A new data escape \S, is added to pcretest; it causes the amounts of store
1575        obtained and freed by both kinds of malloc/free at match time to be added
1576        to the output.
1578     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1579        what's available on my current Linux desktop machine.
1581     3. When matching a UTF-8 string, the test for a valid string at the start has
1582        been extended. If start_offset is not zero, PCRE now checks that it points
1583        to a byte that is the start of a UTF-8 character. If not, it returns
1584        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1585        this is necessary because there may be backward assertions in the pattern.
1586        When matching the same subject several times, it may save resources to use
1587        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1589     4. The code for checking the validity of UTF-8 strings has been tightened so
1590        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1591        containing "overlong sequences".
1593     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1594        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1595        should have been "&", but it just so happened that all the cases this let
1596        through by mistake were picked up later in the function.
1598     6. I had used a variable called "isblank" - this is a C99 function, causing
1599        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1601     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1602        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1603        so the version is shown; (c) stop "make test" echoing "./RunTest".
1605     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1607     9. The prototype for memmove() for systems that don't have it was using
1608        size_t, but the inclusion of the header that defines size_t was later. I've
1609        moved the #includes for the C headers earlier to avoid this.
1611    10. Added some adjustments to the code to make it easier to compiler on certain
1612        special systems:
1614          (a) Some "const" qualifiers were missing.
1615          (b) Added the macro EXPORT before all exported functions; by default this
1616              is defined to be empty.
1617          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1618              that it reads its output file name as an argument instead of writing
1619              to the standard output and assuming this can be redirected.
1621    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1622        class containing characters with values greater than 255, PCRE compilation
1623        went into a loop.
1625    12. A recursive reference to a subpattern that was within another subpattern
1626        that had a minimum quantifier of zero caused PCRE to crash. For example,
1627        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1628        recursion. If the recursively-called subpattern itself had a zero repeat,
1629        that was OK.
1631    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1632        buffer into which it was copied (for escape processing) was still set at
1633        1024, so long lines caused crashes.
1635    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1636        "internal error: code overflow...". This applied to any character class
1637        that was followed by a possessive quantifier.
1639    15. Modified the Makefile to add libpcre.la as a prerequisite for
1640        libpcreposix.la because I was told this is needed for a parallel build to
1641        work.
1643    16. If a pattern that contained .* following optional items at the start was
1644        studied, the wrong optimizing data was generated, leading to matching
1645        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1646        matching string must start with a or b or c. The correct conclusion for
1647        this pattern is that a match can start with any character.
1650    Version 4.4 13-Aug-03
1651    ---------------------
1653     1. In UTF-8 mode, a character class containing characters with values between
1654        127 and 255 was not handled correctly if the compiled pattern was studied.
1655        In fixing this, I have also improved the studying algorithm for such
1656        classes (slightly).
1658     2. Three internal functions had redundant arguments passed to them. Removal
1659        might give a very teeny performance improvement.
1661     3. Documentation bug: the value of the capture_top field in a callout is *one
1662        more than* the number of the hightest numbered captured substring.
1664     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1665        in incorrectly linking with a previously installed version. They now link
1666        explicitly with libpcre.la.
1668     5. configure.in no longer needs to recognize Cygwin specially.
1670     6. A problem in pcre.in for Windows platforms is fixed.
1672     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1673        pcretest, it used to include the size of the study block as part of its
1674        output. Unfortunately, the structure contains a field that has a different
1675        size on different hardware architectures. This meant that the tests that
1676        showed this size failed. As the block is currently always of a fixed size,
1677        this information isn't actually particularly useful in pcretest output, so
1678        I have just removed it.
1680     8. Three pre-processor statements accidentally did not start in column 1.
1681        Sadly, there are *still* compilers around that complain, even though
1682        standard C has not required this for well over a decade. Sigh.
1684     9. In pcretest, the code for checking callouts passed small integers in the
1685        callout_data field, which is a void * field. However, some picky compilers
1686        complained about the casts involved for this on 64-bit systems. Now
1687        pcretest passes the address of the small integer instead, which should get
1688        rid of the warnings.
1690    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1691        both compile and run time, and gives an error if an invalid UTF-8 sequence
1692        is found. There is a option for disabling this check in cases where the
1693        string is known to be correct and/or the maximum performance is wanted.
1695    11. In response to a bug report, I changed one line in Makefile.in from
1697            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1698        to
1699            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1701        to look similar to other lines, but I have no way of telling whether this
1702        is the right thing to do, as I do not use Windows. No doubt I'll get told
1703        if it's wrong...
1706    Version 4.3 21-May-03
1707    ---------------------
1709    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1710       Makefile.
1712    2. Some refactoring to improve the quality of the code:
1714       (i)   The utf8_table... variables are now declared "const".
1716       (ii)  The code for \cx, which used the "case flipping" table to upper case
1717             lower case letters, now just substracts 32. This is ASCII-specific,
1718             but the whole concept of \cx is ASCII-specific, so it seems
1719             reasonable.
1721       (iii) PCRE was using its character types table to recognize decimal and
1722             hexadecimal digits in the pattern. This is silly, because it handles
1723             only 0-9, a-f, and A-F, but the character types table is locale-
1724             specific, which means strange things might happen. A private
1725             table is now used for this - though it costs 256 bytes, a table is
1726             much faster than multiple explicit tests. Of course, the standard
1727             character types table is still used for matching digits in subject
1728             strings against \d.
1730       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1731             ending in _t are). So I've renamed it as ESC_tee.
1733    3. The first argument for regexec() in the POSIX wrapper should have been
1734       defined as "const".
1736    4. Changed pcretest to use malloc() for its buffers so that they can be
1737       Electric Fenced for debugging.
1739    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1740       to read one or more bytes before the start of the subject string. Often this
1741       had no effect on PCRE's behaviour, but in some circumstances it could
1742       provoke a segmentation fault.
1744    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1745       to try to read one or more bytes before the start of the subject string.
1747    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1748       UTF-8 support could misbehave in various ways if the subject string
1749       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1750       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1751       back over UTF-8 characters.)
1754    Version 4.2 14-Apr-03
1755    ---------------------
1757    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1759    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1760         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1761         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1762         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1763         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1764           and BUILD_EXEEXT
1765         Note: automatic setting of the BUILD variables is not yet working
1766         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1767           compile-time but not at link-time
1768         [LINK]: use for linking executables only
1769         make different versions for Windows and non-Windows
1770         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1771           libraries
1772         [LINK_FOR_BUILD]: new variable
1773         [OBJEXT]: use throughout
1774         [EXEEXT]: use throughout
1775         <winshared>: new target
1776         <wininstall>: new target
1777         <dftables.o>: use native compiler
1778         <dftables>: use native linker
1779         <install>: handle Windows platform correctly
1780         <clean>: ditto
1781         <check>: ditto
1782         copy DLL to top builddir before testing
1784       As part of these changes, -no-undefined was removed again. This was reported
1785       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1786       in any case.
1788    3. Some tidies to get rid of compiler warnings:
1790       . In the match_data structure, match_limit was an unsigned long int, whereas
1791         match_call_count was an int. I've made them both unsigned long ints.
1793       . In pcretest the fact that a const uschar * doesn't automatically cast to
1794         a void * provoked a warning.
1796       . Turning on some more compiler warnings threw up some "shadow" variables
1797         and a few more missing casts.
1799    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1800       option, a class that contained a single character with a value between 128
1801       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1803    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1804       option, a class that contained several characters, but with at least one
1805       whose value was between 128 and 255 caused PCRE to crash.
1808    Version 4.1 12-Mar-03
1809    ---------------------
1811    1. Compiling with gcc -pedantic found a couple of places where casts were
1812    needed, and a string in dftables.c that was longer than standard compilers are
1813    required to support.
1815    2. Compiling with Sun's compiler found a few more places where the code could
1816    be tidied up in order to avoid warnings.
1818    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1819    first of these names is deprecated in the latest Autoconf in favour of the name
1820    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1821    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1822    analogy I have changed it to CFLAGS_FOR_BUILD.
1824    4. Added -no-undefined to the linking command in the Makefile, because this is
1825    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1826    linking step for the pcreposix library.
1828    5. PCRE was failing to diagnose the case of two named groups with the same
1829    name.
1831    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1832    literal character that is needed in the subject for a match, and scans along to
1833    ensure that it is present before embarking on the full matching process. This
1834    saves time in cases of nested unlimited repeats that are never going to match.
1835    Problem: the scan can take a lot of time if the subject is very long (e.g.
1836    megabytes), thus penalizing straightforward matches. It is now done only if the
1837    amount of subject to be scanned is less than 1000 bytes.
1839    7. A lesser problem with the same optimization is that it was recording the
1840    first character of an anchored pattern as "needed", thus provoking a search
1841    right along the subject, even when the first match of the pattern was going to
1842    fail. The "needed" character is now not set for anchored patterns, unless it
1843    follows something in the pattern that is of non-fixed length. Thus, it still
1844    fulfils its original purpose of finding quick non-matches in cases of nested
1845    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1848    Version 4.0 17-Feb-03
1849    ---------------------
1851    1. If a comment in an extended regex that started immediately after a meta-item
1852    extended to the end of string, PCRE compiled incorrect data. This could lead to
1853    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1855    2. Moved to autoconf 2.53 and libtool 1.4.2.
1857    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1858    the special perltest8 script is no longer needed - all the tests can be run
1859    from a single perltest script.
1861    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1862    by \s. It has now been removed in PCRE. This means it isn't recognized as
1863    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1864    class [:space:] *does* include VT, thereby creating a mess.
1866    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1867    space and tab.
1869    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1870    its new features into the main test script, reducing the number of scripts.
1872    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1873    were backward compatible, and made the (?i) apply to the whole pattern, as if
1874    /i were given. Now it behaves more logically, and applies the option setting
1875    only to what follows. PCRE has been changed to follow suit. However, if it
1876    finds options settings right at the start of the pattern, it extracts them into
1877    the global options, as before. Thus, they show up in the info data.
1879    8. Added support for the \Q...\E escape sequence. Characters in between are
1880    treated as literals. This is slightly different from Perl in that $ and @ are
1881    also handled as literals inside the quotes. In Perl, they will cause variable
1882    interpolation. Note the following examples:
1884        Pattern            PCRE matches      Perl matches
1886        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1887        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1888        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1890    For compatibility with Perl, \Q...\E sequences are recognized inside character
1891    classes as well as outside them.
1893    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1894    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1895    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1896    signed/unsigned warnings.
1898    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1899    option for pcretest, so I've replaced it by a simple function that does just
1900    that job.
1902    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1903    "pcregrep -".
1905    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1906    Java package. This provides some syntactic sugar for simple cases of what my
1907    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1908    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1909    item, you can use this simplified notation. Note that only makes sense with
1910    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1911    greediness, whatever the setting of the PCRE_UNGREEDY option.
1913    13. A change of greediness default within a pattern was not taking effect at
1914    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1915    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1916    was abstracted outside.
1918    14. PCRE now supports the \G assertion. It is true when the current matching
1919    position is at the start point of the match. This differs from \A when the
1920    starting offset is non-zero. Used with the /g option of pcretest (or similar
1921    code), it works in the same way as it does for Perl's /g option. If all
1922    alternatives of a regex begin with \G, the expression is anchored to the start
1923    match position, and the "anchored" flag is set in the compiled expression.
1925    15. Some bugs concerning the handling of certain option changes within patterns
1926    have been fixed. These applied to options other than (?ims). For example,
1927    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1928    been the other way round. Some of this was related to change 7 above.
1930    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1931    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1932    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1933    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1935    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1936    mode. Unlike ".", it always matches newline, whatever the setting of
1937    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1938    assertions. Perl allows it, but it doesn't (in general) work because it can't
1939    calculate the length of the lookbehind. At least, that's the case for Perl
1940    5.8.0 - I've been told they are going to document that it doesn't work in
1941    future.
1943    18. Added an error diagnosis for escapes that PCRE does not support: these are
1944    \L, \l, \N, \P, \p, \U, \u, and \X.
1946    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1947    reading past the end of the pattern in cases such as /[abcd/.
1949    20. PCRE was getting more memory than necessary for patterns with classes that
1950    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1952    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1953    compiling PCRE for use with Virtual Pascal.
1955    22. Small fix to the Makefile to make it work properly if the build is done
1956    outside the source tree.
1958    23. Added a new extension: a condition to go with recursion. If a conditional
1959    subpattern starts with (?(R) the "true" branch is used if recursion has
1960    happened, whereas the "false" branch is used only at the top level.
1962    24. When there was a very long string of literal characters (over 255 bytes
1963    without UTF support, over 250 bytes with UTF support), the computation of how
1964    much memory was required could be incorrect, leading to segfaults or other
1965    strange effects.
1967    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1968    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1969    there was a subsequent back reference to those brackets. This meant that, for
1970    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1971    possible to check for precisely this case. All we can do is abandon the
1972    optimization if .* occurs inside capturing brackets when there are any back
1973    references whatsoever. (See below for a better fix that came later.)
1975    26. The handling of the optimization for finding the first character of a
1976    non-anchored pattern, and for finding a character that is required later in the
1977    match were failing in some cases. This didn't break the matching; it just
1978    failed to optimize when it could. The way this is done has been re-implemented.
1980    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1982    28. Added a new feature that provides some of the functionality that Perl
1983    provides with (?{...}). The facility is termed a "callout". The way it is done
1984    in PCRE is for the caller to provide an optional function, by setting
1985    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1986    global variable. By default it is unset, which disables all calling out. To get
1987    the function called, the regex must include (?C) at appropriate points. This
1988    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1989    This provides a means of identifying different callout points. When PCRE
1990    reaches such a point in the regex, if pcre_callout has been set, the external
1991    function is called. It is provided with data in a structure called
1992    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1993    matching continues; if it returns a non-zero value, the match at the current
1994    point fails. However, backtracking will occur if possible. [This was changed
1995    later and other features added - see item 49 below.]
1997    29. pcretest is upgraded to test the callout functionality. It provides a
1998    callout function that displays information. By default, it shows the start of
1999    the match and the current position in the text. There are some new data escapes
2000    to vary what happens:
2002        \C+         in addition, show current contents of captured substrings
2003        \C-         do not supply a callout function
2004        \C!n        return 1 when callout number n is reached
2005        \C!n!m      return 1 when callout number n is reached for the mth time
2007    30. If pcregrep was called with the -l option and just a single file name, it
2008    output "<stdin>" if a match was found, instead of the file name.
2010    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2011    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2012    pcre_exec(). This saves a malloc/free per call. The default value of
2013    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2014    when configuring.
2016    32. The default maximum size of a compiled pattern is 64K. There have been a
2017    few cases of people hitting this limit. The code now uses macros to handle the
2018    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2019    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2020    configuring. Tests 2 and 5 work only with 2-byte links because they output
2021    debugging information about compiled patterns.
2023    33. Internal code re-arrangements:
2025    (a) Moved the debugging function for printing out a compiled regex into
2026        its own source file (printint.c) and used #include to pull it into
2027        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2028        separate copies.
2030    (b) Defined the list of op-code names for debugging as a macro in
2031        internal.h so that it is next to the definition of the opcodes.
2033    (c) Defined a table of op-code lengths for simpler skipping along compiled
2034        code. This is again a macro in internal.h so that it is next to the
2035        definition of the opcodes.
2037    34. Added support for recursive calls to individual subpatterns, along the
2038    lines of Robin Houston's patch (but implemented somewhat differently).
2040    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2041    allow it to read and process whole directories in Win32. This code was
2042    contributed by Lionel Fourquaux; it has not been tested by me.
2044    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2045    used to name a group. Names consist of alphanumerics and underscores, and must
2046    be unique. Back references use the syntax (?P=name) and recursive calls use
2047    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2048    numbers. The function pcre_fullinfo() can be used after compilation to extract
2049    a name/number map. There are three relevant calls:
2051      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2052      PCRE_INFO_NAMECOUNT            yields the number of entries
2053      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2055    The map is a vector of fixed-size entries. The size of each entry depends on
2056    the length of the longest name used. The first two bytes of each entry are the
2057    group number, most significant byte first. There follows the corresponding
2058    name, zero terminated. The names are in alphabetical order.
2060    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2061    case instead of 255. Making it the same both with and without UTF-8 support
2062    means that the same test output works with both.
2064    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2065    calling malloc() with a zero argument.
2067    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2068    optimization. I've improved things by keeping a bitmap of backreferences with
2069    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2070    fact referenced, the optimization can be applied. It is unlikely that a
2071    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2072    the match to follow \n) will appear inside brackets with a number greater than
2073    31, but if it does, any back reference > 31 suppresses the optimization.
2075    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2076    of disabling numbered capturing parentheses. Any opening parenthesis that is
2077    not followed by ? behaves as if it were followed by ?: but named parentheses
2078    can still be used for capturing (and they will acquire numbers in the usual
2079    way).
2081    41. Redesigned the return codes from the match() function into yes/no/error so
2082    that errors can be passed back from deep inside the nested calls. A malloc
2083    failure while inside a recursive subpattern call now causes the
2084    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2086    42. It is now possible to set a limit on the number of times the match()
2087    function is called in a call to pcre_exec(). This facility makes it possible to
2088    limit the amount of recursion and backtracking, though not in a directly
2089    obvious way, because the match() function is used in a number of different
2090    circumstances. The count starts from zero for each position in the subject
2091    string (for non-anchored patterns). The default limit is, for compatibility, a
2092    large number, namely 10 000 000. You can change this in two ways:
2094    (a) When configuring PCRE before making, you can use --with-match-limit=n
2095        to set a default value for the compiled library.
2097    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2098        a different value is set. See 45 below.
2100    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2102    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2103    of things that can be changed at compile time. The first argument specifies
2104    what is wanted and the second points to where the information is to be placed.
2105    The current list of available information is:
2107      PCRE_CONFIG_UTF8
2109    The output is an integer that is set to one if UTF-8 support is available;
2110    otherwise it is set to zero.
2114    The output is an integer that it set to the value of the code that is used for
2115    newline. It is either LF (10) or CR (13).
2119    The output is an integer that contains the number of bytes used for internal
2120    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2124    The output is an integer that contains the threshold above which the POSIX
2125    interface uses malloc() for output vectors. See item 31 above.
2129    The output is an unsigned integer that contains the default limit of the number
2130    of match() calls in a pcre_exec() execution. See 42 above.
2132    44. pcretest has been upgraded by the addition of the -C option. This causes it
2133    to extract all the available output from the new pcre_config() function, and to
2134    output it. The program then exits immediately.
2136    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2137    order to support additional features. One way would have been to define
2138    pcre_exec2() (for example) with extra arguments, but this would not have been
2139    extensible, and would also have required all calls to the original function to
2140    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2141    is used for passing in "extra" data from pcre_study().
2143    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2144    contains the following fields:
2146      flags         a bitmap indicating which of the following fields are set
2147      study_data    opaque data from pcre_study()
2148      match_limit   a way of specifying a limit on match() calls for a specific
2149                      call to pcre_exec()
2150      callout_data  data for callouts (see 49 below)
2152    The flag bits are also defined in pcre.h, and are
2158    The pcre_study() function now returns one of these new pcre_extra blocks, with
2159    the actual study data pointed to by the study_data field, and the
2160    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2161    before. That is, this change is entirely upwards-compatible and requires no
2162    change to existing code.
2164    If you want to pass in additional data to pcre_exec(), you can either place it
2165    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2166    block.
2168    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2169    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2170    times with different match limits, until it finds the minimum value needed for
2171    pcre_exec() to complete. The value is then output. This can be instructive; for
2172    most simple matches the number is quite small, but for pathological cases it
2173    gets very large very quickly.
2175    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2176    returns the size of the data block pointed to by the study_data field in a
2177    pcre_extra block, that is, the value that was passed as the argument to
2178    pcre_malloc() when PCRE was getting memory in which to place the information
2179    created by pcre_study(). The fourth argument should point to a size_t variable.
2180    pcretest has been extended so that this information is shown after a successful
2181    pcre_study() call when information about the compiled regex is being displayed.
2183    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2184    because what follows is always an absolute path. (Later: it turns out that this
2185    is more than cosmetic for MinGW, because it doesn't like empty path
2186    components.)
2188    49. Some changes have been made to the callout feature (see 28 above):
2190    (i)  A callout function now has three choices for what it returns:
2192           0  =>  success, carry on matching
2193         > 0  =>  failure at this point, but backtrack if possible
2194         < 0  =>  serious error, return this value from pcre_exec()
2196         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2197         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2198         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2199         use by callout functions. It will never be used by PCRE itself.
2201    (ii) The pcre_extra structure (see 45 above) has a void * field called
2202         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2203         pcre_callout_block structure has a field of the same name. The contents of
2204         the field passed in the pcre_extra structure are passed to the callout
2205         function in the corresponding field in the callout block. This makes it
2206         easier to use the same callout-containing regex from multiple threads. For
2207         testing, the pcretest program has a new data escape
2209           \C*n        pass the number n (may be negative) as callout_data
2211         If the callout function in pcretest receives a non-zero value as
2212         callout_data, it returns that value.
2214    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2215    there were some redundant $(CFLAGS) in commands that are now specified as
2216    $(LINK), which already includes $(CFLAGS).
2218    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2219    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2220    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2221    one-byte characters throughout. Note that case-insensitive matching applies
2222    only to characters whose values are less than 256. PCRE doesn't support the
2223    notion of cases for higher-valued characters.
2225    (i)   A character class whose characters are all within 0-255 is handled as
2226          a bit map, and the map is inverted for negative classes. Previously, a
2227          character > 255 always failed to match such a class; however it should
2228          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2230    (ii)  A negated character class with a single character < 255 is coded as
2231          "not this character" (OP_NOT). This wasn't working properly when the test
2232          character was multibyte, either singly or repeated.
2234    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2235          mode, for example: \x{100}{2,3}.
2237    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2238          singly or repeated) now correctly test multibyte characters. However,
2239          PCRE doesn't recognize any characters with values greater than 255 as
2240          digits, spaces, or word characters. Such characters always match \D, \S,
2241          and \W, and never match \d, \s, or \w.
2243    (v)   Classes may now contain characters and character ranges with values
2244          greater than 255. For example: [ab\x{100}-\x{400}].
2246    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2247          PCRE in UTF-8 mode.
2249    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2250    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2251    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2252    value.)
2254    53. The single man page has become too large. I have therefore split it up into
2255    a number of separate man pages. These also give rise to individual HTML pages;
2256    these are now put in a separate directory, and there is an index.html page that
2257    lists them all. Some hyperlinking between the pages has been installed.
2259    54. Added convenience functions for handling named capturing parentheses.
2261    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2262    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2263    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2264    are faulted.
2266    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2267    calling configure. These values are used when compiling the dftables.c program
2268    which is run to generate the source of the default character tables. They
2269    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2270    you will need to set these values.
2272    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2275    Version 3.9 02-Jan-02
2276    ---------------------
2278    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2280    2. If --disable-static was given, the building process failed when trying to
2281    build pcretest and pcregrep. (For some reason it was using libtool to compile
2282    them, which is not right, as they aren't part of the library.)
2285    Version 3.8 18-Dec-01
2286    ---------------------
2288    1. The experimental UTF-8 code was completely screwed up. It was packing the
2289    bytes in the wrong order. How dumb can you get?
2292    Version 3.7 29-Oct-01
2293    ---------------------
2295    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2296    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2297    this didn't happen under Solaris 8, where I normally test things.
2299    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2300    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2301    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2302    this fix an hour or so after the initial 3.7 release.)
2305    Version 3.6 23-Oct-01
2306    ---------------------
2308    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2309    offsets passed as NULL with zero offset count.
2311    2. The config.guess and config.sub files had not been updated when I moved to
2312    the latest autoconf.
2315    Version 3.5 15-Aug-01
2316    ---------------------
2318    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2319    had been forgotten.
2321    2. By using declared but undefined structures, we can avoid using "void"
2322    definitions in pcre.h while keeping the internal definitions of the structures
2323    private.
2325    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2326    user point of view, this means that both static and shared libraries are built
2327    by default, but this can be individually controlled. More of the work of
2328    handling this static/shared cases is now inside libtool instead of PCRE's make
2329    file.
2331    4. The pcretest utility is now installed along with pcregrep because it is
2332    useful for users (to test regexs) and by doing this, it automatically gets
2333    relinked by libtool. The documentation has been turned into a man page, so
2334    there are now .1, .txt, and .html versions in /doc.
2336    5. Upgrades to pcregrep:
2337       (i)   Added long-form option names like gnu grep.
2338       (ii)  Added --help to list all options with an explanatory phrase.
2339       (iii) Added -r, --recursive to recurse into sub-directories.
2340       (iv)  Added -f, --file to read patterns from a file.
2342    6. pcre_exec() was referring to its "code" argument before testing that
2343    argument for NULL (and giving an error if it was NULL).
2345    7. Upgraded Makefile.in to allow for compiling in a different directory from
2346    the source directory.
2348    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2349    options bits, the pointer it was passed was to an int instead of to an unsigned
2350    long int. This mattered only on 64-bit systems.
2352    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2353    generated) instead of pcre.in, which it its source. Also made the same change
2354    in several of the .c files.
2356    10. A new release of gcc defines printf() as a macro, which broke pcretest
2357    because it had an ifdef in the middle of a string argument for printf(). Fixed
2358    by using separate calls to printf().
2360    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2361    script, to force use of CR or LF instead of \n in the source. On non-Unix
2362    systems, the value can be set in config.h.
2364    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2365    absolute limit. Changed the text of the error message to make this clear, and
2366    likewise updated the man page.
2368    13. The limit of 99 on the number of capturing subpatterns has been removed.
2369    The new limit is 65535, which I hope will not be a "real" limit.
2372    Version 3.4 22-Aug-00
2373    ---------------------
2375    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2377    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2380    Version 3.3 01-Aug-00
2381    ---------------------
2383    1. If an octal character was given, but the value was greater than \377, it
2384    was not getting masked to the least significant bits, as documented. This could
2385    lead to crashes in some systems.
2387    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2388    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2390    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2391    These just pass their arguments on to (pcre_free)(), but they are provided
2392    because some uses of PCRE bind it to non-C systems that can call its functions,
2393    but cannot call free() or pcre_free() directly.
2395    4. Add "make test" as a synonym for "make check". Corrected some comments in
2396    the Makefile.
2398    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2399    Makefile.
2401    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2402    command called pgrep for grepping around the active processes.
2404    7. Added the beginnings of support for UTF-8 character strings.
2406    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2407    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2408    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2409    out for the ar command.)
2412    Version 3.2 12-May-00
2413    ---------------------
2415    This is purely a bug fixing release.
2417    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2418    of ZA. This was just one example of several cases that could provoke this bug,
2419    which was introduced by change 9 of version 2.00. The code for breaking
2420    infinite loops after an iteration that matches an empty string was't working
2421    correctly.
2423    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2424    when matched against abbab (for example). After matching an empty string, it
2425    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2426    caused it to match further down the string than it should.
2428    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2429    was there because it doesn't seem to be needed, and it causes trouble on some
2430    systems, as it is not a Standard C header. It has been removed.
2432    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2433    were reported on the Macintosh. The changes were from
2435      while ((c = *(++ptr)) != 0 && c != '\n');
2436    to
2437      while ((c = *(++ptr)) != 0 && c != '\n') ;
2439    Totally extraordinary, but if that's what it takes...
2441    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2442    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2443    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2444    assumes the way PCRE uses memmove() (always moving upwards).
2446    6. PCRE is being used in one environment where strchr() is not available. There
2447    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2448    faster code anyway.
2451    Version 3.1 09-Feb-00
2452    ---------------------
2454    The only change in this release is the fixing of some bugs in Makefile.in for
2455    the "install" target:
2457    (1) It was failing to install pcreposix.h.
2459    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2462    Version 3.0 01-Feb-00
2463    ---------------------
2465    1. Add support for the /+ modifier to perltest (to output $` like it does in
2466    pcretest).
2468    2. Add support for the /g modifier to perltest.
2470    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2471    matches null strings.
2473    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2474    pattern. Perl treats empty patterns specially - it reuses the most recent
2475    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2476    effect.
2478    5. The POSIX interface was broken in that it was just handing over the POSIX
2479    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2480    required a bigger vector, with some working space on the end. This means that
2481    the POSIX wrapper now has to get and free some memory, and copy the results.
2483    6. Added some simple autoconf support, placing the test data and the
2484    documentation in separate directories, re-organizing some of the
2485    information files, and making it build pcre-config (a GNU standard). Also added
2486    libtool support for building PCRE as a shared library, which is now the
2487    default.
2489    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2490    09 are not valid octal constants. Single digits will be used for minor values
2491    less than 10.
2493    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2494    existing programs that set these in the POSIX interface can use PCRE without
2495    modification.
2497    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2498    return all that pcre_info() returns, plus additional data. The pcre_info()
2499    function is retained for compatibility, but is considered to be obsolete.
2501    10. Added experimental recursion feature (?R) to handle one common case that
2502    Perl 5.6 will be able to do with (?p{...}).
2504    11. Added support for POSIX character classes like [:alpha:], which Perl is
2505    adopting.
2508    Version 2.08 31-Aug-99
2509    ----------------------
2511    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2512    trying to match at the startoffset position, but instead was moving forward to
2513    the next newline as if a previous match had failed.
2515    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2516    and could get into a loop if a null string was matched other than at the start
2517    of the subject.
2519    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2520    be distinguished at compile time, and for completeness also added PCRE_DATE.
2522    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2523    in GnuWin32 environments.
2526    Version 2.07 29-Jul-99
2527    ----------------------
2529    1. The documentation is now supplied in plain text form and HTML as well as in
2530    the form of man page sources.
2532    2. C++ compilers don't like assigning (void *) values to other pointer types.
2533    In particular this affects malloc(). Although there is no problem in Standard
2534    C, I've put in casts to keep C++ compilers happy.
2536    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2537    should be (const char *).
2539    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2540    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2541    However, I haven't made this a standard facility. The documentation doesn't
2542    mention it, and the Makefile doesn't support it.
2544    5. The Makefile now contains an "install" target, with editable destinations at
2545    the top of the file. The pcretest program is not installed.
2547    6. pgrep -V now gives the PCRE version number and date.
2549    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2550    causing the entire string to be ignored, instead of just the last character.
2552    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2553    non-matching string, it can take a very, very long time, even for strings of
2554    quite modest length, because of the nested recursion. PCRE now does better in
2555    some of these cases. It does this by remembering the last required literal
2556    character in the pattern, and pre-searching the subject to ensure it is present
2557    before running the real match. In other words, it applies a heuristic to detect
2558    some types of certain failure quickly, and in the above example, if presented
2559    with a string that has no trailing " it gives "no match" very quickly.
2561    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2562    other alternatives are tried instead.
2565    Version 2.06 09-Jun-99
2566    ----------------------
2568    1. Change pcretest's output for amount of store used to show just the code
2569    space, because the remainder (the data block) varies in size between 32-bit and
2570    64-bit systems.
2572    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2573    start matching at. This allows lookbehinds to work when searching for multiple
2574    occurrences in a string.
2576    3. Added additional options to pcretest for testing multiple occurrences:
2578       /+   outputs the rest of the string that follows a match
2579       /g   loops for multiple occurrences, using the new startoffset argument
2580       /G   loops for multiple occurrences by passing an incremented pointer
2582    4. PCRE wasn't doing the "first character" optimization for patterns starting
2583    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2584    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2585    the letter 'x'. On long subject strings, this gives a significant speed-up.
2588    Version 2.05 21-Apr-99
2589    ----------------------
2591    1. Changed the type of magic_number from int to long int so that it works
2592    properly on 16-bit systems.
2594    2. Fixed a bug which caused patterns starting with .* not to work correctly
2595    when the subject string contained newline characters. PCRE was assuming
2596    anchoring for such patterns in all cases, which is not correct because .* will
2597    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2598    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2599    must be retried after every newline in the subject.
2602    Version 2.04 18-Feb-99
2603    ----------------------
2605    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2606    computation of the store needed to hold the pattern was incorrect (too large).
2607    If such patterns were nested a few deep, this could multiply and become a real
2608    problem.
2610    2. Added /M option to pcretest to show the memory requirement of a specific
2611    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2613    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2614    compiled in such a way that the backtracking after subsequent failure was
2615    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2616    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2619    Version 2.03 02-Feb-99
2620    ----------------------
2622    1. Fixed typo and small mistake in man page.
2624    2. Added 4th condition (GPL supersedes if conflict) and created separate
2625    LICENCE file containing the conditions.
2627    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2628    Perl, that is the internal \ allows the delimiter to be included in the
2629    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2630    the final delimiter, add \ to the end of the pattern (to test the error).
2632    4. Added the convenience functions for extracting substrings after a successful
2633    match. Updated pcretest to make it able to test these functions.
2636    Version 2.02 14-Jan-99
2637    ----------------------
2639    1. Initialized the working variables associated with each extraction so that
2640    their saving and restoring doesn't refer to uninitialized store.
2642    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2643    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2644    fix the problem.
2646    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2647    calls, and wasn't printing the correct value for compiling calls. Increased the
2648    default value of LOOPREPEAT, and the number of significant figures in the
2649    times.
2651    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2653    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2654    a building problem on Windows NT with a FAT file system.
2657    Version 2.01 21-Oct-98
2658    ----------------------
2660    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2661    to character tables built by pcre_maketables() in the current locale. If NULL
2662    is passed, the default tables are used.
2665    Version 2.00 24-Sep-98
2666    ----------------------
2668    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2669    it any more.
2671    2. Allow quantification of (?>) groups, and make it work correctly.
2673    3. The first character computation wasn't working for (?>) groups.
2675    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2676    end of the subject) and add 5.005's \z, which really does match only at the
2677    very end of the subject.
2679    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2681    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2682    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2683    localized options. All options to pcre_study() were also removed.
2685    7. Add other new features from 5.005:
2687       $(?<=           positive lookbehind
2688       $(?<!           negative lookbehind
2689       (?imsx-imsx)    added the unsetting capability
2690                       such a setting is global if at outer level; local otherwise
2691       (?imsx-imsx:)   non-capturing groups with option setting
2692       (?(cond)re|re)  conditional pattern matching
2694       A backreference to itself in a repeated group matches the previous
2695       captured string.
2697    8. General tidying up of studying (both automatic and via "study")
2698    consequential on the addition of new assertions.
2700    9. As in 5.005, unlimited repeated groups that could match an empty substring
2701    are no longer faulted at compile time. Instead, the loop is forcibly broken at
2702    runtime if any iteration does actually match an empty substring.
2704    10. Include the RunTest script in the distribution.
2706    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2707    discrepancies, some of which were old and were also with respect to 5.004. They
2708    have now been fixed.
2711    Version 1.09 28-Apr-98
2712    ----------------------
2714    1. A negated single character class followed by a quantifier with a minimum
2715    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
2716    program crashes, or just wrong answers. This did not apply to negated classes
2717    containing more than one character, or to minima other than one.
2720  Version 1.08 27-Mar-98  Version 1.08 27-Mar-98
2721  ----------------------  ----------------------

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