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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.5 04-Jan-08
5    ---------------------
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
79    14. Added --file-offsets and --line-offsets to pcregrep.
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
98    19. Added --enable-pcretest-libreadline.
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I removed one of the increments, but Craig sent a
103        later patch that removed the other one (the right fix) and added unit tests
104        that check the return values (which was not done before).
106    21. Several CMake things:
108        (1) Arranged that, when cmake is used on Unix, the libraries end up with
109            the names libpcre and libpcreposix, not just pcre and pcreposix.
111        (2) The above change means that pcretest and pcregrep are now correctly
112            linked with the newly-built libraries, not previously installed ones.
116    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
117        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
118        UTF-8 newline character). The key issue is that the pattern starts .*;
119        this means that the match must be either at the beginning, or after a
120        newline. The bug was in the code for advancing after a failed match and
121        checking that the new position followed a newline. It was not taking
122        account of UTF-8 characters correctly.
124    23. PCRE was behaving differently from Perl in the way it recognized POSIX
125        character classes. PCRE was not treating the sequence [:...:] as a
126        character class unless the ... were all letters. Perl, however, seems to
127        allow any characters between [: and :], though of course it rejects as
128        unknown any "names" that contain non-letters, because all the known class
129        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
130        for example, whereas PCRE did not - it did not recognize a POSIX character
131        class. This seemed a bit dangerous, so the code has been changed to be
132        closer to Perl. The behaviour is not identical to Perl, because PCRE will
133        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
134        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
135        Perl does, and where it didn't before.
137    24. Rewrite so as to remove the single use of %n from pcregrep because in some
138        Windows environments %n is disabled by default.
141    Version 7.4 21-Sep-07
142    ---------------------
144    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
145        means that a class such as [\s] counted as "explicit reference to CR or
146        LF". That isn't really right - the whole point of the change was to try to
147        help when there was an actual mention of one of the two characters. So now
148        the change happens only if \r or \n (or a literal CR or LF) character is
149        encountered.
151    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
152        of both had grown to the point where there were only 3 bits left.
153        Fortunately, there was spare space in the data structure, and so I have
154        moved the internal flags into a new 16-bit field to free up more option
155        bits.
157    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
158        but did not set the internal JCHANGED flag - either of these is enough to
159        control the way the "get" function works - but the PCRE_INFO_JCHANGED
160        facility is supposed to tell if (?J) was ever used, so now (?J) at the
161        start sets both bits.
163    4.  Added options (at build time, compile time, exec time) to change \R from
164        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
166    5.  doc/pcresyntax.html was missing from the distribution.
168    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
169        compatibility, even though it is no longer used.
171    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
172        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
173        windows.h file is present (where different names are used). [This was
174        reversed later after testing - see 16 below.]
176    8.  Changed all #include <config.h> to #include "config.h". There were also
177        some further <pcre.h> cases that I changed to "pcre.h".
179    9.  When pcregrep was used with the --colour option, it missed the line ending
180        sequence off the lines that it output.
182    10. It was pointed out to me that arrays of string pointers cause lots of
183        relocations when a shared library is dynamically loaded. A technique of
184        using a single long string with a table of offsets can drastically reduce
185        these. I have refactored PCRE in four places to do this. The result is
186        dramatic:
188          Originally:                          290
189          After changing UCP table:            187
190          After changing error message table:   43
191          After changing table of "verbs"       36
192          After changing table of Posix names   22
194        Thanks to the folks working on Gregex for glib for this insight.
196    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
197        unicode-properties was also set.
199    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
201    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
202        checked only for CRLF.
204    14. Added casts to pcretest.c to avoid compiler warnings.
206    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
208    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
209        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
210        entirely. This removes changes made in 7 above.
212    17. The CMake files have been updated, and there is now more information about
213        building with CMake in the NON-UNIX-USE document.
216    Version 7.3 28-Aug-07
217    ---------------------
219     1. In the rejigging of the build system that eventually resulted in 7.1, the
220        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
221        brackets there is not right, since it causes compilers to look for an
222        installed pcre.h, not the version that is in the source that is being
223        compiled (which of course may be different). I have changed it back to:
225          #include "pcre.h"
227        I have a vague recollection that the change was concerned with compiling in
228        different directories, but in the new build system, that is taken care of
229        by the VPATH setting the Makefile.
231     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
232        when the subject happened to end in the byte 0x85 (e.g. if the last
233        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
234        characters but of course it shouldn't be taken as a newline when it is part
235        of another character. The bug was that, for an unlimited repeat of . in
236        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
237        characters when looking for a newline.
239     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
241     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
242        in debug output.
244     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
245        long printing in the pcrecpp unittest when running under MinGW.
247     6. ESC_K was left out of the EBCDIC table.
249     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
250        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
251        limit also applies to "virtual nesting" when a pattern is recursive, and in
252        this case 1000 isn't so big. I have been able to remove this limit at the
253        expense of backing off one optimization in certain circumstances. Normally,
254        when pcre_exec() would call its internal match() function recursively and
255        immediately return the result unconditionally, it uses a "tail recursion"
256        feature to save stack. However, when a subpattern that can match an empty
257        string has an unlimited repetition quantifier, it no longer makes this
258        optimization. That gives it a stack frame in which to save the data for
259        checking that an empty string has been matched. Previously this was taken
260        from the 1000-entry workspace that had been reserved. So now there is no
261        explicit limit, but more stack is used.
263     8. Applied Daniel's patches to solve problems with the import/export magic
264        syntax that is required for Windows, and which was going wrong for the
265        pcreposix and pcrecpp parts of the library. These were overlooked when this
266        problem was solved for the main library.
268     9. There were some crude static tests to avoid integer overflow when computing
269        the size of patterns that contain repeated groups with explicit upper
270        limits. As the maximum quantifier is 65535, the maximum group length was
271        set at 30,000 so that the product of these two numbers did not overflow a
272        32-bit integer. However, it turns out that people want to use groups that
273        are longer than 30,000 bytes (though not repeat them that many times).
274        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
275        made it possible to implement the integer overflow checks in a much more
276        dynamic way, which I have now done. The artificial limitation on group
277        length has been removed - we now have only the limit on the total length of
278        the compiled pattern, which depends on the LINK_SIZE setting.
280    10. Fixed a bug in the documentation for get/copy named substring when
281        duplicate names are permitted. If none of the named substrings are set, the
282        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
283        empty string.
285    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
286        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
287        because the ] is interpreted as the first data character and the
288        terminating ] is not found. PCRE has been made compatible with Perl in this
289        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
290        cause memory overwriting.
292    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
293        string has been matched (to stop an infinite loop). It was not recognizing
294        a conditional subpattern that could match an empty string if that
295        subpattern was within another subpattern. For example, it looped when
296        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
297        condition was not nested. This bug has been fixed.
299    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
300        past the start of the subject in the presence of bytes with the top bit
301        set, for example "\x8aBCD".
303    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
304        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
306    14. Optimized (?!) to (*FAIL).
308    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
309        This restricts code points to be within the range 0 to 0x10FFFF, excluding
310        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
311        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
312        does: it's just the validity check that is more restrictive.
314    16. Inserted checks for integer overflows during escape sequence (backslash)
315        processing, and also fixed erroneous offset values for syntax errors during
316        backslash processing.
318    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
319        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
321    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
322        caused an overrun.
324    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
325        something other than just ASCII characters) inside a group that had an
326        unlimited repeat caused a loop at compile time (while checking to see
327        whether the group could match an empty string).
329    20. Debugging a pattern containing \p or \P could cause a crash. For example,
330        [\P{Any}] did so. (Error in the code for printing property names.)
332    21. An orphan \E inside a character class could cause a crash.
334    22. A repeated capturing bracket such as (A)? could cause a wild memory
335        reference during compilation.
337    23. There are several functions in pcre_compile() that scan along a compiled
338        expression for various reasons (e.g. to see if it's fixed length for look
339        behind). There were bugs in these functions when a repeated \p or \P was
340        present in the pattern. These operators have additional parameters compared
341        with \d, etc, and these were not being taken into account when moving along
342        the compiled data. Specifically:
344        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
345            length.
347        (b) An item such as \pL+ within a repeated group could cause crashes or
348            loops.
350        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
351            "reference to non-existent subpattern" error.
353        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
355    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
356        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
358    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
360    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
361        character were causing crashes (broken optimization).
363    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
364        \p or \P) caused a compile-time loop.
366    28. More problems have arisen in unanchored patterns when CRLF is a valid line
367        break. For example, the unstudied pattern [\r\n]A does not match the string
368        "\r\nA" because change 7.0/46 below moves the current point on by two
369        characters after failing to match at the start. However, the pattern \nA
370        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
371        the same is true. There doesn't seem any very clean way out of this, but
372        what I have chosen to do makes the common cases work: PCRE now takes note
373        of whether there can be an explicit match for \r or \n anywhere in the
374        pattern, and if so, 7.0/46 no longer applies. As part of this change,
375        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
376        pattern has explicit CR or LF references.
378    29. Added (*CR) etc for changing newline setting at start of pattern.
381    Version 7.2 19-Jun-07
382    ---------------------
384     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
385        which is apparently normally available under Windows.
387     2. Re-jig the pcregrep tests with different newline settings in an attempt
388        to make them independent of the local environment's newline setting.
390     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
392     4. Some of the "internals" tests were previously cut out when the link size
393        was not 2, because the output contained actual offsets. The recent new
394        "Z" feature of pcretest means that these can be cut out, making the tests
395        usable with all link sizes.
397     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
398        stack recursion. This gives a massive performance boost under BSD, but just
399        a small improvement under Linux. However, it saves one field in the frame
400        in all cases.
402     6. Added more features from the forthcoming Perl 5.10:
404        (a) (?-n) (where n is a string of digits) is a relative subroutine or
405            recursion call. It refers to the nth most recently opened parentheses.
407        (b) (?+n) is also a relative subroutine call; it refers to the nth next
408            to be opened parentheses.
410        (c) Conditions that refer to capturing parentheses can be specified
411            relatively, for example, (?(-2)... or (?(+3)...
413        (d) \K resets the start of the current match so that everything before
414            is not part of it.
416        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
418        (f) \g{name} is another synonym - part of Perl 5.10's unification of
419            reference syntax.
421        (g) (?| introduces a group in which the numbering of parentheses in each
422            alternative starts with the same number.
424        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
426     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
429     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
430        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
431        for detecting groups that can match an empty string.
433     9. A pattern with a very large number of alternatives (more than several
434        hundred) was running out of internal workspace during the pre-compile
435        phase, where pcre_compile() figures out how much memory will be needed. A
436        bit of new cunning has reduced the workspace needed for groups with
437        alternatives. The 1000-alternative test pattern now uses 12 bytes of
438        workspace instead of running out of the 4096 that are available.
440    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
442    11. Applied patch from Google to remove an optimization that didn't quite work.
443        The report of the bug said:
445          pcrecpp::RE("a*").FullMatch("aaa") matches, while
446          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
447          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
449    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
450        it matched the wrong number of bytes.
453    Version 7.1 24-Apr-07
454    ---------------------
456     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
457        that is more "standard", making use of automake and other Autotools. There
458        is some re-arrangement of the files and adjustment of comments consequent
459        on this.
461     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
462        for recursive directory scanning broke on some systems because the files
463        are not scanned in any specific order and on different systems the order
464        was different. A call to "sort" has been inserted into RunGrepTest for the
465        approprate test as a short-term fix. In the longer term there may be an
466        alternative.
468     3. I had an email from Eric Raymond about problems translating some of PCRE's
469        man pages to HTML (despite the fact that I distribute HTML pages, some
470        people do their own conversions for various reasons). The problems
471        concerned the use of low-level troff macros .br and .in. I have therefore
472        removed all such uses from the man pages (some were redundant, some could
473        be replaced by .nf/.fi pairs). The 132html script that I use to generate
474        HTML has been updated to handle .nf/.fi and to complain if it encounters
475        .br or .in.
477     4. Updated comments in configure.ac that get placed in config.h.in and also
478        arranged for config.h to be included in the distribution, with the name
479        config.h.generic, for the benefit of those who have to compile without
480        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
482     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
483        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
484        makevp.bat for the current PCRE, using the additional files
485        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
487     6. A Windows user reported a minor discrepancy with test 2, which turned out
488        to be caused by a trailing space on an input line that had got lost in his
489        copy. The trailing space was an accident, so I've just removed it.
491     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
492        that is needed.
494     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
495        as "const" (a) because they are and (b) because it helps the PHP
496        maintainers who have recently made a script to detect big data structures
497        in the php code that should be moved to the .rodata section. I remembered
498        to update Builducptable as well, so it won't revert if ucptable.h is ever
499        re-created.
501     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
502        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
503        order to be able to cut out the UTF-8 tables in the latter when UTF-8
504        support is not required. This saves 1.5-2K of code, which is important in
505        some applications.
507        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
508        so as not to refer to the tables, even though these functions will never be
509        called when UTF-8 support is disabled. Otherwise there are problems with a
510        shared library.
512    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
514        (a) It was defining its arguments as char * instead of void *.
516        (b) It was assuming that all moves were upwards in memory; this was true
517            a long time ago when I wrote it, but is no longer the case.
519        The emulated memove() is provided for those environments that have neither
520        memmove() nor bcopy(). I didn't think anyone used it these days, but that
521        is clearly not the case, as these two bugs were recently reported.
523    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
524        and Detrail to create the HTML documentation, the .txt form of the man
525        pages, and it removes trailing spaces from listed files. It also creates
526        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
527        case, it wraps all the #defines with #ifndefs. This script should be run
528        before "make dist".
530    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
531        with Unicode property support.
533        (a) For a maximizing quantifier, if the two different cases of the
534            character were of different lengths in their UTF-8 codings (there are
535            some cases like this - I found 11), and the matching function had to
536            back up over a mixture of the two cases, it incorrectly assumed they
537            were both the same length.
539        (b) When PCRE was configured to use the heap rather than the stack for
540            recursion during matching, it was not correctly preserving the data for
541            the other case of a UTF-8 character when checking ahead for a match
542            while processing a minimizing repeat. If the check also involved
543            matching a wide character, but failed, corruption could cause an
544            erroneous result when trying to check for a repeat of the original
545            character.
547    13. Some tidying changes to the testing mechanism:
549        (a) The RunTest script now detects the internal link size and whether there
550            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
551            values substituted by "configure". (The RunGrepTest script already did
552            this for UTF-8.) The configure.ac script no longer substitutes the
553            relevant variables.
555        (b) The debugging options /B and /D in pcretest show the compiled bytecode
556            with length and offset values. This means that the output is different
557            for different internal link sizes. Test 2 is skipped for link sizes
558            other than 2 because of this, bypassing the problem. Unfortunately,
559            there was also a test in test 3 (the locale tests) that used /B and
560            failed for link sizes other than 2. Rather than cut the whole test out,
561            I have added a new /Z option to pcretest that replaces the length and
562            offset values with spaces. This is now used to make test 3 independent
563            of link size. (Test 2 will be tidied up later.)
565    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
566        segmentation fault instead of returning the appropriate error message.
568    15. In multiline mode when the newline sequence was set to "any", the pattern
569        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
570        This doesn't seem right; it now treats the CRLF combination as the line
571        ending, and so does not match in that case. It's only a pattern such as ^$
572        that would hit this one: something like ^ABC$ would have failed after \r
573        and then tried again after \r\n.
575    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
576        in an attempt to make files that differ only in their line terminators
577        compare equal. This works on Linux.
579    17. Under certain error circumstances pcregrep might try to free random memory
580        as it exited. This is now fixed, thanks to valgrind.
582    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
583        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
584        was because its rules for how to advance for /g after matching an empty
585        string at the end of a line did not allow for this case. They now check for
586        it specially.
588    20. pcretest is supposed to handle patterns and data of any length, by
589        extending its buffers when necessary. It was getting this wrong when the
590        buffer for a data line had to be extended.
592    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
593        CRLF as a newline sequence.
595    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
596        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
597        I have nevertheless tidied it up.
599    23. Added some casts to kill warnings from HP-UX ia64 compiler.
601    24. Added a man page for pcre-config.
604    Version 7.0 19-Dec-06
605    ---------------------
607     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
608        moving to gcc 4.1.1.
610     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
611        sys/time.h, which is documented as needed for this function. It doesn't
612        seem to matter on Linux, but it showed up on some releases of OS X.
614     3. It seems that there are systems where bytes whose values are greater than
615        127 match isprint() in the "C" locale. The "C" locale should be the
616        default when a C program starts up. In most systems, only ASCII printing
617        characters match isprint(). This difference caused the output from pcretest
618        to vary, making some of the tests fail. I have changed pcretest so that:
620        (a) When it is outputting text in the compiled version of a pattern, bytes
621            other than 32-126 are always shown as hex escapes.
623        (b) When it is outputting text that is a matched part of a subject string,
624            it does the same, unless a different locale has been set for the match
625            (using the /L modifier). In this case, it uses isprint() to decide.
627     4. Fixed a major bug that caused incorrect computation of the amount of memory
628        required for a compiled pattern when options that changed within the
629        pattern affected the logic of the preliminary scan that determines the
630        length. The relevant options are -x, and -i in UTF-8 mode. The result was
631        that the computed length was too small. The symptoms of this bug were
632        either the PCRE error "internal error: code overflow" from pcre_compile(),
633        or a glibc crash with a message such as "pcretest: free(): invalid next
634        size (fast)". Examples of patterns that provoked this bug (shown in
635        pcretest format) are:
637          /(?-x: )/x
638          /(?x)(?-x: \s*#\s*)/
639          /((?i)[\x{c0}])/8
640          /(?i:[\x{c0}])/8
642        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
643        is now done differently.
645     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
646        wrapper classes; (b) implement a new function in the C++ scanner that is
647        more efficient than the old way of doing things because it avoids levels of
648        recursion in the regex matching; (c) add a paragraph to the documentation
649        for the FullMatch() function.
651     6. The escape sequence \n was being treated as whatever was defined as
652        "newline". Not only was this contrary to the documentation, which states
653        that \n is character 10 (hex 0A), but it also went horribly wrong when
654        "newline" was defined as CRLF. This has been fixed.
656     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
657        was being set to -1 for the "end of line" case (supposedly a value that no
658        character can have). Though this value is never used (the check for end of
659        line is "zero bytes in current character"), it caused compiler complaints.
660        I've changed it to 0xffffffff.
662     8. In pcre_version.c, the version string was being built by a sequence of
663        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
664        string (as it is for production releases) called a macro with an empty
665        argument. The C standard says the result of this is undefined. The gcc
666        compiler treats it as an empty string (which was what was wanted) but it is
667        reported that Visual C gives an error. The source has been hacked around to
668        avoid this problem.
670     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
671        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
672        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
673        of them did).
675    10. Originally, pcretest opened its input and output without "b"; then I was
676        told that "b" was needed in some environments, so it was added for release
677        5.0 to both the input and output. (It makes no difference on Unix-like
678        systems.) Later I was told that it is wrong for the input on Windows. I've
679        now abstracted the modes into two macros, to make it easier to fiddle with
680        them, and removed "b" from the input mode under Windows.
682    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
684    12. Added -help and --help to pcretest as an official way of being reminded
685        of the options.
687    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
688        and pcrecpp.cc because they annoy compilers at high warning levels.
690    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
692    15. Fixed an occurrence of == in configure.ac that should have been = (shell
693        scripts are not C programs :-) and which was not noticed because it works
694        on Linux.
696    16. pcretest is supposed to handle any length of pattern and data line (as one
697        line or as a continued sequence of lines) by extending its input buffer if
698        necessary. This feature was broken for very long pattern lines, leading to
699        a string of junk being passed to pcre_compile() if the pattern was longer
700        than about 50K.
702    17. I have done a major re-factoring of the way pcre_compile() computes the
703        amount of memory needed for a compiled pattern. Previously, there was code
704        that made a preliminary scan of the pattern in order to do this. That was
705        OK when PCRE was new, but as the facilities have expanded, it has become
706        harder and harder to keep it in step with the real compile phase, and there
707        have been a number of bugs (see for example, 4 above). I have now found a
708        cunning way of running the real compile function in a "fake" mode that
709        enables it to compute how much memory it would need, while actually only
710        ever using a few hundred bytes of working memory and without too many
711        tests of the mode. This should make future maintenance and development
712        easier. A side effect of this work is that the limit of 200 on the nesting
713        depth of parentheses has been removed (though this was never a serious
714        limitation, I suspect). However, there is a downside: pcre_compile() now
715        runs more slowly than before (30% or more, depending on the pattern). I
716        hope this isn't a big issue. There is no effect on runtime performance.
718    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
719        newline (only possible for the last line of a file) and it was a
720        pattern that set a locale (followed by /Lsomething), pcretest crashed.
722    19. Added additional timing features to pcretest. (1) The -tm option now times
723        matching only, not compiling. (2) Both -t and -tm can be followed, as a
724        separate command line item, by a number that specifies the number of
725        repeats to use when timing. The default is 50000; this gives better
726        precision, but takes uncomfortably long for very large patterns.
728    20. Extended pcre_study() to be more clever in cases where a branch of a
729        subpattern has no definite first character. For example, (a*|b*)[cd] would
730        previously give no result from pcre_study(). Now it recognizes that the
731        first character must be a, b, c, or d.
733    21. There was an incorrect error "recursive call could loop indefinitely" if
734        a subpattern (or the entire pattern) that was being tested for matching an
735        empty string contained only one non-empty item after a nested subpattern.
736        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
737        incorrectly, because the \d was being skipped in the check.
739    22. The pcretest program now has a new pattern option /B and a command line
740        option -b, which is equivalent to adding /B to every pattern. This causes
741        it to show the compiled bytecode, without the additional information that
742        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
743        is the same as /B/I).
745    23. A new optimization is now able automatically to treat some sequences such
746        as a*b as a*+b. More specifically, if something simple (such as a character
747        or a simple class like \d) has an unlimited quantifier, and is followed by
748        something that cannot possibly match the quantified thing, the quantifier
749        is automatically "possessified".
751    24. A recursive reference to a subpattern whose number was greater than 39
752        went wrong under certain circumstances in UTF-8 mode. This bug could also
753        have affected the operation of pcre_study().
755    25. Realized that a little bit of performance could be had by replacing
756        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
758    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
760    27. Possessive quantifiers such as a++ were previously implemented by turning
761        them into atomic groups such as ($>a+). Now they have their own opcodes,
762        which improves performance. This includes the automatically created ones
763        from 23 above.
765    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
766        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
767        the first matched character to be a colon. This applied both to named and
768        numbered groups.
770    29. The ucpinternal.h header file was missing its idempotency #ifdef.
772    30. I was sent a "project" file called libpcre.a.dev which I understand makes
773        building PCRE on Windows easier, so I have included it in the distribution.
775    31. There is now a check in pcretest against a ridiculously large number being
776        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
777        loop, the loop is abandoned.
779    32. Forward references to subpatterns in conditions such as (?(2)...) where
780        subpattern 2 is defined later cause pcre_compile() to search forwards in
781        the pattern for the relevant set of parentheses. This search went wrong
782        when there were unescaped parentheses in a character class, parentheses
783        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
785    33. "Subroutine" calls and backreferences were previously restricted to
786        referencing subpatterns earlier in the regex. This restriction has now
787        been removed.
789    34. Added a number of extra features that are going to be in Perl 5.10. On the
790        whole, these are just syntactic alternatives for features that PCRE had
791        previously implemented using the Python syntax or my own invention. The
792        other formats are all retained for compatibility.
794        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
795            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
796            also .NET compatible.
798        (b) A recursion or subroutine call to a named group can now be defined as
799            (?&name) as well as (?P>name).
801        (c) A backreference to a named group can now be defined as \k<name> or
802            \k'name' as well as (?P=name). The new forms, as well as being in Perl
803            5.10, are also .NET compatible.
805        (d) A conditional reference to a named group can now use the syntax
806            (?(<name>) or (?('name') as well as (?(name).
808        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
809            groups (named and numbered) that are never evaluated inline, but can be
810            called as "subroutines" from elsewhere. In effect, the DEFINE condition
811            is always false. There may be only one alternative in such a group.
813        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
814            as the simple (?(R). The condition is true only if the most recent
815            recursion is that of the given number or name. It does not search out
816            through the entire recursion stack.
818        (g) The escape \gN or \g{N} has been added, where N is a positive or
819            negative number, specifying an absolute or relative reference.
821    35. Tidied to get rid of some further signed/unsigned compiler warnings and
822        some "unreachable code" warnings.
824    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
825        things, this adds five new scripts.
827    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
828        There were also incompatibilities regarding the handling of \Q..\E inside
829        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
830        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
832    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
833        matches an empty string, and forcibly breaks the loop. There were bugs in
834        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
835        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
836        separate and independent bugs (that affected different cases) have been
837        fixed.
839    39. Refactored the code to abolish the use of different opcodes for small
840        capturing bracket numbers. This is a tidy that I avoided doing when I
841        removed the limit on the number of capturing brackets for 3.5 back in 2001.
842        The new approach is not only tidier, it makes it possible to reduce the
843        memory needed to fix the previous bug (38).
845    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
846        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
847        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
848        mode.
850    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
851        report.
853    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
854        copy construction and assignment in the C++ wrapper.
856    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
857        couple of bugs that could have given wrong results in the "--newline=crlf"
858        case.
860    44. Added a number of casts and did some reorganization of signed/unsigned int
861        variables following suggestions from Dair Grant. Also renamed the variable
862        "this" as "item" because it is a C++ keyword.
864    45. Arranged for dftables to add
866          #include "pcre_internal.h"
868        to pcre_chartables.c because without it, gcc 4.x may remove the array
869        definition from the final binary if PCRE is built into a static library and
870        dead code stripping is activated.
872    46. For an unanchored pattern, if a match attempt fails at the start of a
873        newline sequence, and the newline setting is CRLF or ANY, and the next two
874        characters are CRLF, advance by two characters instead of one.
877    Version 6.7 04-Jul-06
878    ---------------------
880     1. In order to handle tests when input lines are enormously long, pcretest has
881        been re-factored so that it automatically extends its buffers when
882        necessary. The code is crude, but this _is_ just a test program. The
883        default size has been increased from 32K to 50K.
885     2. The code in pcre_study() was using the value of the re argument before
886        testing it for NULL. (Of course, in any sensible call of the function, it
887        won't be NULL.)
889     3. The memmove() emulation function in pcre_internal.h, which is used on
890        systems that lack both memmove() and bcopy() - that is, hardly ever -
891        was missing a "static" storage class specifier.
893     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
894        containing an extended class (one that cannot be represented by a bitmap
895        because it contains high-valued characters or Unicode property items, e.g.
896        [\pZ]). Almost always one would set UTF-8 mode when processing such a
897        pattern, but PCRE should not loop if you do not (it no longer does).
898        [Detail: two cases were found: (a) a repeated subpattern containing an
899        extended class; (b) a recursive reference to a subpattern that followed a
900        previous extended class. It wasn't skipping over the extended class
901        correctly when UTF-8 mode was not set.]
903     5. A negated single-character class was not being recognized as fixed-length
904        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
905        compile error "lookbehind assertion is not fixed length".
907     6. The RunPerlTest auxiliary script was showing an unexpected difference
908        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
909        write a Perl script that can interpret lines of an input file either as
910        byte characters or as UTF-8, which is what "perltest" was being required to
911        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
912        can't do is switch easily at run time between having the "use utf8;" pragma
913        or not. In the end, I fudged it by using the RunPerlTest script to insert
914        "use utf8;" explicitly for the UTF-8 tests.
916     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
917        the end of the subject string, contrary to the documentation and to what
918        Perl does. This was true of both matching functions. Now it matches only at
919        the start of the subject and immediately after *internal* newlines.
921     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
922        a pointer to an int instead of a pointer to an unsigned long int. This
923        caused problems on 64-bit systems.
925     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
926        instance of the 'standard' template library not being so standard".
928    10. There was no check on the number of named subpatterns nor the maximum
929        length of a subpattern name. The product of these values is used to compute
930        the size of the memory block for a compiled pattern. By supplying a very
931        long subpattern name and a large number of named subpatterns, the size
932        computation could be caused to overflow. This is now prevented by limiting
933        the length of names to 32 characters, and the number of named subpatterns
934        to 10,000.
936    11. Subpatterns that are repeated with specific counts have to be replicated in
937        the compiled pattern. The size of memory for this was computed from the
938        length of the subpattern and the repeat count. The latter is limited to
939        65535, but there was no limit on the former, meaning that integer overflow
940        could in principle occur. The compiled length of a repeated subpattern is
941        now limited to 30,000 bytes in order to prevent this.
943    12. Added the optional facility to have named substrings with the same name.
945    13. Added the ability to use a named substring as a condition, using the
946        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
947        are numbers (not recommended). Forward references are permitted.
949    14. Added forward references in named backreferences (if you see what I mean).
951    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
952        pattern could run off the end of the subject. For example, the pattern
953        "(?s)(.{1,5})"8 did this with the subject "ab".
955    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
956        PCRE_CASELESS was set when matching characters that were quantified with ?
957        or *.
959    17. A character class other than a single negated character that had a minimum
960        but no maximum quantifier - for example [ab]{6,} - was not handled
961        correctly by pce_dfa_exec(). It would match only one character.
963    18. A valid (though odd) pattern that looked like a POSIX character
964        class but used an invalid character after [ (for example [[,abc,]]) caused
965        pcre_compile() to give the error "Failed: internal error: code overflow" or
966        in some cases to crash with a glibc free() error. This could even happen if
967        the pattern terminated after [[ but there just happened to be a sequence of
968        letters, a binary zero, and a closing ] in the memory that followed.
970    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
971        over the years. Originally (before any Unicode support), just the bottom 8
972        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
973        output from "man perlunicode" includes this:
975          The regular expression compiler produces polymorphic opcodes.  That
976          is, the pattern adapts to the data and automatically switches to
977          the Unicode character scheme when presented with Unicode data--or
978          instead uses a traditional byte scheme when presented with byte
979          data.
981        Sadly, a wide octal escape does not cause a switch, and in a string with
982        no other multibyte characters, these octal escapes are treated as before.
983        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
984        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
985        Unicode string.
987        I have not perpetrated such confusion in PCRE. Up till now, it took just
988        the bottom 8 bits, as in old Perl. I have now made octal escapes with
989        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
990        translate to the appropriate multibyte character.
992    29. Applied some refactoring to reduce the number of warnings from Microsoft
993        and Borland compilers. This has included removing the fudge introduced
994        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
995        a warning about an unused variable.
997    21. PCRE has not included VT (character 0x0b) in the set of whitespace
998        characters since release 4.0, because Perl (from release 5.004) does not.
999        [Or at least, is documented not to: some releases seem to be in conflict
1000        with the documentation.] However, when a pattern was studied with
1001        pcre_study() and all its branches started with \s, PCRE still included VT
1002        as a possible starting character. Of course, this did no harm; it just
1003        caused an unnecessary match attempt.
1005    22. Removed a now-redundant internal flag bit that recorded the fact that case
1006        dependency changed within the pattern. This was once needed for "required
1007        byte" processing, but is no longer used. This recovers a now-scarce options
1008        bit. Also moved the least significant internal flag bit to the most-
1009        significant bit of the word, which was not previously used (hangover from
1010        the days when it was an int rather than a uint) to free up another bit for
1011        the future.
1013    23. Added support for CRLF line endings as well as CR and LF. As well as the
1014        default being selectable at build time, it can now be changed at runtime
1015        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1016        specify that it is scanning data with non-default line endings.
1018    24. Changed the definition of CXXLINK to make it agree with the definition of
1019        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1021    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1022        recursions. This makes a big different to stack usage for some patterns.
1024    26. If a subpattern containing a named recursion or subroutine reference such
1025        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1026        the space required for the compiled pattern went wrong and gave too small a
1027        value. Depending on the environment, this could lead to "Failed: internal
1028        error: code overflow at offset 49" or "glibc detected double free or
1029        corruption" errors.
1031    27. Applied patches from Google (a) to support the new newline modes and (b) to
1032        advance over multibyte UTF-8 characters in GlobalReplace.
1034    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1035        difference for some implementation of PCRE in some Windows version.
1037    29. Added some extra testing facilities to pcretest:
1039        \q<number>   in a data line sets the "match limit" value
1040        \Q<number>   in a data line sets the "match recursion limt" value
1041        -S <number>  sets the stack size, where <number> is in megabytes
1043        The -S option isn't available for Windows.
1046    Version 6.6 06-Feb-06
1047    ---------------------
1049     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1050        in pcreposix.h. I have copied the definition from pcre.h.
1052     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1053        because pcre.h is no longer a built file.
1055     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1056        not normally included in the compiled code.
1059    Version 6.5 01-Feb-06
1060    ---------------------
1062     1. When using the partial match feature with pcre_dfa_exec(), it was not
1063        anchoring the second and subsequent partial matches at the new starting
1064        point. This could lead to incorrect results. For example, with the pattern
1065        /1234/, partially matching against "123" and then "a4" gave a match.
1067     2. Changes to pcregrep:
1069        (a) All non-match returns from pcre_exec() were being treated as failures
1070            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1071            error message is output. Some extra information is given for the
1072            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1073            probably the only errors that are likely to be caused by users (by
1074            specifying a regex that has nested indefinite repeats, for instance).
1075            If there are more than 20 of these errors, pcregrep is abandoned.
1077        (b) A binary zero was treated as data while matching, but terminated the
1078            output line if it was written out. This has been fixed: binary zeroes
1079            are now no different to any other data bytes.
1081        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1082            used to set a locale for matching. The --locale=xxxx long option has
1083            been added (no short equivalent) to specify a locale explicitly on the
1084            pcregrep command, overriding the environment variables.
1086        (d) When -B was used with -n, some line numbers in the output were one less
1087            than they should have been.
1089        (e) Added the -o (--only-matching) option.
1091        (f) If -A or -C was used with -c (count only), some lines of context were
1092            accidentally printed for the final match.
1094        (g) Added the -H (--with-filename) option.
1096        (h) The combination of options -rh failed to suppress file names for files
1097            that were found from directory arguments.
1099        (i) Added the -D (--devices) and -d (--directories) options.
1101        (j) Added the -F (--fixed-strings) option.
1103        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1105        (l) Added the --colo(u)r option.
1107        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1108            is not present by default.
1110     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1111        items such as (?R) or (?1), when the recursion could match a number of
1112        alternatives. If it matched one of the alternatives, but subsequently,
1113        outside the recursion, there was a failure, the code tried to back up into
1114        the recursion. However, because of the way PCRE is implemented, this is not
1115        possible, and the result was an incorrect result from the match.
1117        In order to prevent this happening, the specification of recursion has
1118        been changed so that all such subpatterns are automatically treated as
1119        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1121     4. I had overlooked the fact that, in some locales, there are characters for
1122        which isalpha() is true but neither isupper() nor islower() are true. In
1123        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1124        and ordfeminine) are like this. This affected the treatment of \w and \W
1125        when they appeared in character classes, but not when they appeared outside
1126        a character class. The bit map for "word" characters is now created
1127        separately from the results of isalnum() instead of just taking it from the
1128        upper, lower, and digit maps. (Plus the underscore character, of course.)
1130     5. The above bug also affected the handling of POSIX character classes such as
1131        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1132        permanent tables. Instead, the bit maps for such a class were previously
1133        created as the appropriate unions of the upper, lower, and digit bitmaps.
1134        Now they are created by subtraction from the [[:word:]] class, which has
1135        its own bitmap.
1137     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1138        It is created by subtracting the vertical space characters (\x09, \x0a,
1139        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1140        subtraction was done in the overall bitmap for a character class, meaning
1141        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1142        be recognized. This bug has been fixed.
1144     7. Patches from the folks at Google:
1146          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1147          real life, but is still worth protecting against".
1149          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1150          regular expressions".
1152          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1153          have it.
1155          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1156          "configure" and the latter not, in order to fix a problem somebody had
1157          with compiling the Arg class on HP-UX.
1159          (e) Improve the error-handling of the C++ wrapper a little bit.
1161          (f) New tests for checking recursion limiting.
1163     8. The pcre_memmove() function, which is used only if the environment does not
1164        have a standard memmove() function (and is therefore rarely compiled),
1165        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1166        returning a result (though PCRE never actually uses the result).
1168     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1169        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1170        returned instead of calling malloc() with an overflowing number that would
1171        most likely cause subsequent chaos.
1173    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1175    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1176        with this option is matched, the nmatch and pmatch options of regexec() are
1177        ignored.
1179    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1180        provided in case anyone wants to the the POSIX interface with UTF-8
1181        strings.
1183    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1184        C++ linking (needed for some HP-UX environments).
1186    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1187        (unused parameter) and in the pcre_printint() function (omitted "default"
1188        switch label when the default is to do nothing).
1190    15. Added some code to make it possible, when PCRE is compiled as a C++
1191        library, to replace subject pointers for pcre_exec() with a smart pointer
1192        class, thus making it possible to process discontinuous strings.
1194    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1195        much the same function. They were added by different people who were trying
1196        to make PCRE easy to compile on non-Unix systems. It has been suggested
1197        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1198        for compiling on Windows systems. I have therefore replaced it with
1199        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1200        defaults to "extern" for C or "extern C" for C++, which works fine on
1201        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1202        SCOPE with something explicit in config.h. In addition:
1204        (a) pcreposix.h still had just "extern" instead of either of these macros;
1205            I have replaced it with PCRE_DATA_SCOPE.
1207        (b) Functions such as _pcre_xclass(), which are internal to the library,
1208            but external in the C sense, all had PCRE_EXPORT in their definitions.
1209            This is apparently wrong for the Windows case, so I have removed it.
1210            (It makes no difference on Unix-like systems.)
1212    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1213        of recursive calls to match(). This is different to MATCH_LIMIT because
1214        that limits the total number of calls to match(), not all of which increase
1215        the depth of recursion. Limiting the recursion depth limits the amount of
1216        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1217        when PCRE is compiled, and changed at run time. A patch from Google adds
1218        this functionality to the C++ interface.
1220    18. Changes to the handling of Unicode character properties:
1222        (a) Updated the table to Unicode 4.1.0.
1224        (b) Recognize characters that are not in the table as "Cn" (undefined).
1226        (c) I revised the way the table is implemented to a much improved format
1227            which includes recognition of ranges. It now supports the ranges that
1228            are defined in UnicodeData.txt, and it also amalgamates other
1229            characters into ranges. This has reduced the number of entries in the
1230            table from around 16,000 to around 3,000, thus reducing its size
1231            considerably. I realized I did not need to use a tree structure after
1232            all - a binary chop search is just as efficient. Having reduced the
1233            number of entries, I extended their size from 6 bytes to 8 bytes to
1234            allow for more data.
1236        (d) Added support for Unicode script names via properties such as \p{Han}.
1238    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1239        matching that character.
1241    20. When matching a repeated Unicode property with a minimum greater than zero,
1242        (for example \pL{2,}), PCRE could look past the end of the subject if it
1243        reached it while seeking the minimum number of characters. This could
1244        happen only if some of the characters were more than one byte long, because
1245        there is a check for at least the minimum number of bytes.
1247    21. Refactored the implementation of \p and \P so as to be more general, to
1248        allow for more different types of property in future. This has changed the
1249        compiled form incompatibly. Anybody with saved compiled patterns that use
1250        \p or \P will have to recompile them.
1252    22. Added "Any" and "L&" to the supported property types.
1254    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1255        but give a compile time error if the value is greater than 0xff.
1257    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1258        accidentally not being installed or uninstalled.
1260    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1261        made were to insert the current release number. This seemed silly, because
1262        it made things harder for people building PCRE on systems that don't run
1263        "configure". I have turned pcre.h into a distributed file, no longer built
1264        by "configure", with the version identification directly included. There is
1265        no longer a pcre.h.in file.
1267        However, this change necessitated a change to the pcre-config script as
1268        well. It is built from pcre-config.in, and one of the substitutions was the
1269        release number. I have updated configure.ac so that ./configure now finds
1270        the release number by grepping pcre.h.
1272    26. Added the ability to run the tests under valgrind.
1275    Version 6.4 05-Sep-05
1276    ---------------------
1278     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1279        "--" to be printed when multiple files were scanned, even when none of the
1280        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1281        consider it to be a bug, and have restored the previous behaviour.
1283     2. A couple of code tidies to get rid of compiler warnings.
1285     3. The pcretest program used to cheat by referring to symbols in the library
1286        whose names begin with _pcre_. These are internal symbols that are not
1287        really supposed to be visible externally, and in some environments it is
1288        possible to suppress them. The cheating is now confined to including
1289        certain files from the library's source, which is a bit cleaner.
1291     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1292        file's purpose clearer.
1294     5. Reorganized pcre_ucp_findchar().
1297    Version 6.3 15-Aug-05
1298    ---------------------
1300     1. The file libpcre.pc.in did not have general read permission in the tarball.
1302     2. There were some problems when building without C++ support:
1304        (a) If C++ support was not built, "make install" and "make test" still
1305            tried to test it.
1307        (b) There were problems when the value of CXX was explicitly set. Some
1308            changes have been made to try to fix these, and ...
1310        (c) --disable-cpp can now be used to explicitly disable C++ support.
1312        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1313            backslash in a target when C++ was disabled. This confuses some
1314            versions of "make", apparently. Using an intermediate variable solves
1315            this. (Same for CPP_LOBJ.)
1317     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1318        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1319        necessary on certain architectures.
1321     4. Added a setting of -export-symbols-regex to the link command to remove
1322        those symbols that are exported in the C sense, but actually are local
1323        within the library, and not documented. Their names all begin with
1324        "_pcre_". This is not a perfect job, because (a) we have to except some
1325        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1326        available (and never for static libraries). I have made a note to try to
1327        find a way round (a) in the future.
1330    Version 6.2 01-Aug-05
1331    ---------------------
1333     1. There was no test for integer overflow of quantifier values. A construction
1334        such as {1111111111111111} would give undefined results. What is worse, if
1335        a minimum quantifier for a parenthesized subpattern overflowed and became
1336        negative, the calculation of the memory size went wrong. This could have
1337        led to memory overwriting.
1339     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1341     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1342        operating environments where this matters.
1344     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1345        PCRE options from within the C++ wrapper.
1347     5. Named capturing subpatterns were not being correctly counted when a pattern
1348        was compiled. This caused two problems: (a) If there were more than 100
1349        such subpatterns, the calculation of the memory needed for the whole
1350        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1351        back references of the form \12, where the number was greater than 9, were
1352        not recognized as back references, even though there were sufficient
1353        previous subpatterns.
1355     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1356        versions of gcc, e.g. 2.95.4.
1359    Version 6.1 21-Jun-05
1360    ---------------------
1362     1. There was one reference to the variable "posix" in pcretest.c that was not
1363        surrounded by "#if !defined NOPOSIX".
1365     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1366        the cross-check on the old pcre_info() function, for the benefit of the
1367        cut-down version of PCRE that is currently imported into Exim.
1369     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1370        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1371        patterns that start (?i) but I don't think that matters. The use of (?i) is
1372        just an example; this all applies to the other options as well.
1374     4. Since libtool seems to echo the compile commands it is issuing, the output
1375        from "make" can be reduced a bit by putting "@" in front of each libtool
1376        compile command.
1378     5. Patch from the folks at Google for configure.in to be a bit more thorough
1379        in checking for a suitable C++ installation before trying to compile the
1380        C++ stuff. This should fix a reported problem when a compiler was present,
1381        but no suitable headers.
1383     6. The man pages all had just "PCRE" as their title. I have changed them to
1384        be the relevant file name. I have also arranged that these names are
1385        retained in the file doc/pcre.txt, which is a concatenation in text format
1386        of all the man pages except the little individual ones for each function.
1388     7. The NON-UNIX-USE file had not been updated for the different set of source
1389        files that come with release 6. I also added a few comments about the C++
1390        wrapper.
1393    Version 6.0 07-Jun-05
1394    ---------------------
1396     1. Some minor internal re-organization to help with my DFA experiments.
1398     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1399        didn't matter for the library itself when fully configured, but did matter
1400        when compiling without UCP support, or within Exim, where the ucp files are
1401        not imported.
1403     3. Refactoring of the library code to split up the various functions into
1404        different source modules. The addition of the new DFA matching code (see
1405        below) to a single monolithic source would have made it really too
1406        unwieldy, quite apart from causing all the code to be include in a
1407        statically linked application, when only some functions are used. This is
1408        relevant even without the DFA addition now that patterns can be compiled in
1409        one application and matched in another.
1411        The downside of splitting up is that there have to be some external
1412        functions and data tables that are used internally in different modules of
1413        the library but which are not part of the API. These have all had their
1414        names changed to start with "_pcre_" so that they are unlikely to clash
1415        with other external names.
1417     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1418        a different (DFA) algorithm. Although it is slower than the original
1419        function, it does have some advantages for certain types of matching
1420        problem.
1422     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1423        including restarting after a partial match.
1425     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1426        defined when compiling for Windows was sent to me. I have put it into the
1427        code, though I have no means of testing or verifying it.
1429     7. Added the pcre_refcount() auxiliary function.
1431     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1432        match before or at the first newline in the subject string. In pcretest,
1433        the /f option on a pattern can be used to set this.
1435     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1436        would behave wrongly. This has been present in PCRE since release 4.0.
1438    10. A number of changes to the pcregrep command:
1440        (a) Refactored how -x works; insert ^(...)$ instead of setting
1441            PCRE_ANCHORED and checking the length, in preparation for adding
1442            something similar for -w.
1444        (b) Added the -w (match as a word) option.
1446        (c) Refactored the way lines are read and buffered so as to have more
1447            than one at a time available.
1449        (d) Implemented a pcregrep test script.
1451        (e) Added the -M (multiline match) option. This allows patterns to match
1452            over several lines of the subject. The buffering ensures that at least
1453            8K, or the rest of the document (whichever is the shorter) is available
1454            for matching (and similarly the previous 8K for lookbehind assertions).
1456        (f) Changed the --help output so that it now says
1458              -w, --word-regex(p)
1460            instead of two lines, one with "regex" and the other with "regexp"
1461            because that confused at least one person since the short forms are the
1462            same. (This required a bit of code, as the output is generated
1463            automatically from a table. It wasn't just a text change.)
1465        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1466            option but starts with a hyphen. Could be a pattern or a path name
1467            starting with a hyphen, for instance.
1469        (h) "-" can be given as a file name to represent stdin.
1471        (i) When file names are being printed, "(standard input)" is used for
1472            the standard input, for compatibility with GNU grep. Previously
1473            "<stdin>" was used.
1475        (j) The option --label=xxx can be used to supply a name to be used for
1476            stdin when file names are being printed. There is no short form.
1478        (k) Re-factored the options decoding logic because we are going to add
1479            two more options that take data. Such options can now be given in four
1480            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1482        (l) Added the -A, -B, and -C options for requesting that lines of context
1483            around matches be printed.
1485        (m) Added the -L option to print the names of files that do not contain
1486            any matching lines, that is, the complement of -l.
1488        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1489            continue to scan other files.
1491        (o) The -s option was incorrectly implemented. For compatibility with other
1492            greps, it now suppresses the error message for a non-existent or non-
1493            accessible file (but not the return code). There is a new option called
1494            -q that suppresses the output of matching lines, which was what -s was
1495            previously doing.
1497        (p) Added --include and --exclude options to specify files for inclusion
1498            and exclusion when recursing.
1500    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1501        Hopefully, it now does.
1503    12. Missing cast in pcre_study().
1505    13. Added an "uninstall" target to the makefile.
1507    14. Replaced "extern" in the function prototypes in Makefile.in with
1508        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1509        world, but is set differently for Windows.
1511    15. Added a second compiling function called pcre_compile2(). The only
1512        difference is that it has an extra argument, which is a pointer to an
1513        integer error code. When there is a compile-time failure, this is set
1514        non-zero, in addition to the error test pointer being set to point to an
1515        error message. The new argument may be NULL if no error number is required
1516        (but then you may as well call pcre_compile(), which is now just a
1517        wrapper). This facility is provided because some applications need a
1518        numeric error indication, but it has also enabled me to tidy up the way
1519        compile-time errors are handled in the POSIX wrapper.
1521    16. Added VPATH=.libs to the makefile; this should help when building with one
1522        prefix path and installing with another. (Or so I'm told by someone who
1523        knows more about this stuff than I do.)
1525    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1526        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1527        match everything, including newlines. This is not POSIX-compatible, but
1528        somebody wanted the feature. From pcretest it can be activated by using
1529        both the P and the s flags.
1531    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1533    19. libpcre.pc was being incorrectly installed as executable.
1535    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1536        it now also looks for '\r' so that it will work unmodified on Windows.
1538    21. Added Google's contributed C++ wrapper to the distribution.
1540    22. Added some untidy missing memory free() calls in pcretest, to keep
1541        Electric Fence happy when testing.
1545    Version 5.0 13-Sep-04
1546    ---------------------
1548     1. Internal change: literal characters are no longer packed up into items
1549        containing multiple characters in a single byte-string. Each character
1550        is now matched using a separate opcode. However, there may be more than one
1551        byte in the character in UTF-8 mode.
1553     2. The pcre_callout_block structure has two new fields: pattern_position and
1554        next_item_length. These contain the offset in the pattern to the next match
1555        item, and its length, respectively.
1557     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1558        insertion of callouts before each pattern item. Added the /C option to
1559        pcretest to make use of this.
1561     4. On the advice of a Windows user, the lines
1563          #if defined(_WIN32) || defined(WIN32)
1564          _setmode( _fileno( stdout ), 0x8000 );
1565          #endif  /* defined(_WIN32) || defined(WIN32) */
1567        have been added to the source of pcretest. This apparently does useful
1568        magic in relation to line terminators.
1570     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1571        for the benefit of those environments where the "b" makes a difference.
1573     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1574        to know about it. I have put a hack into configure.in that adds in code
1575        to set GCC=yes if CC=icc. This seems to end up at a point in the
1576        generated configure script that is early enough to affect the setting of
1577        compiler options, which is what is needed, but I have no means of testing
1578        whether it really works. (The user who reported this had patched the
1579        generated configure script, which of course I cannot do.)
1581        LATER: After change 22 below (new libtool files), the configure script
1582        seems to know about icc (and also ecc). Therefore, I have commented out
1583        this hack in configure.in.
1585     7. Added support for pkg-config (2 patches were sent in).
1587     8. Negated POSIX character classes that used a combination of internal tables
1588        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1589        [[:^ascii]]. Typically, they would match almost any characters. The other
1590        POSIX classes were not broken in this way.
1592     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1593        to find the match, as PCRE was deluded into thinking that the match had to
1594        start at the start point or following a newline. The same bug applied to
1595        patterns with negative forward assertions or any backward assertions
1596        preceding ".*" at the start, unless the pattern required a fixed first
1597        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1599    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1600        starting at the last subject character, bytes beyond the end of the subject
1601        string were read.
1603    11. Renamed the variable "class" as "classbits" to make life easier for C++
1604        users. (Previously there was a macro definition, but it apparently wasn't
1605        enough.)
1607    12. Added the new field "tables" to the extra data so that tables can be passed
1608        in at exec time, or the internal tables can be re-selected. This allows
1609        a compiled regex to be saved and re-used at a later time by a different
1610        program that might have everything at different addresses.
1612    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1613        -R library as well as a -L library.
1615    14. The debugging options of pcretest (-d on the command line or D on a
1616        pattern) showed incorrect output for anything following an extended class
1617        that contained multibyte characters and which was followed by a quantifier.
1619    15. Added optional support for general category Unicode character properties
1620        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1621        support. It adds about 90K to the size of the library. The meanings of the
1622        inbuilt class escapes such as \d and \s have NOT been changed.
1624    16. Updated pcredemo.c to include calls to free() to release the memory for the
1625        compiled pattern.
1627    17. The generated file chartables.c was being created in the source directory
1628        instead of in the building directory. This caused the build to fail if the
1629        source directory was different from the building directory, and was
1630        read-only.
1632    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1633        file. No doubt somebody will tell me if they don't make sense... Also added
1634        Dan Mooney's comments about building on OpenVMS.
1636    19. Added support for partial matching via the PCRE_PARTIAL option for
1637        pcre_exec() and the \P data escape in pcretest.
1639    20. Extended pcretest with 3 new pattern features:
1641        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1642              write the compiled pattern to the file whose name is "rest-of-line".
1643              This is a straight binary dump of the data, with the saved pointer to
1644              the character tables forced to be NULL. The study data, if any, is
1645              written too. After writing, pcretest reads a new pattern.
1647        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1648              compiled pattern from the given file. There must not be any
1649              occurrences of "<" in the file name (pretty unlikely); if there are,
1650              pcretest will instead treat the initial "<" as a pattern delimiter.
1651              After reading in the pattern, pcretest goes on to read data lines as
1652              usual.
1654        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1655              and 16-bit fields in a compiled pattern, to simulate a pattern that
1656              was compiled on a host of opposite endianness.
1658    21. The pcre-exec() function can now cope with patterns that were compiled on
1659        hosts of opposite endianness, with this restriction:
1661          As for any compiled expression that is saved and used later, the tables
1662          pointer field cannot be preserved; the extra_data field in the arguments
1663          to pcre_exec() should be used to pass in a tables address if a value
1664          other than the default internal tables were used at compile time.
1666    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1667        now diagnosed as an error. Previously, most of the time, a negative number
1668        would have been treated as zero, but if in addition "ovector" was passed as
1669        NULL, a crash could occur.
1671    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1672        new versions from the libtool 1.5 distribution (the last one is a copy of
1673        a file called libtool.m4). This seems to have fixed the need to patch
1674        "configure" to support Darwin 1.3 (which I used to do). However, I still
1675        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1676        workstation).
1678    24. Changed the PCRE licence to be the more standard "BSD" licence.
1681    Version 4.5 01-Dec-03
1682    ---------------------
1684     1. There has been some re-arrangement of the code for the match() function so
1685        that it can be compiled in a version that does not call itself recursively.
1686        Instead, it keeps those local variables that need separate instances for
1687        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1688        needs to "recurse". Keeping track of where control must go is done by means
1689        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1690        hide most of the details from the main code, and operates only if
1691        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1692        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1693        operating.
1695        To make it easier for callers to provide specially tailored get/free
1696        functions for this usage, two new functions, pcre_stack_malloc, and
1697        pcre_stack_free, are used. They are always called in strict stacking order,
1698        and the size of block requested is always the same.
1700        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1701        PCRE has been compiled to use the stack or the heap for recursion. The
1702        -C option of pcretest uses this to show which version is compiled.
1704        A new data escape \S, is added to pcretest; it causes the amounts of store
1705        obtained and freed by both kinds of malloc/free at match time to be added
1706        to the output.
1708     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1709        what's available on my current Linux desktop machine.
1711     3. When matching a UTF-8 string, the test for a valid string at the start has
1712        been extended. If start_offset is not zero, PCRE now checks that it points
1713        to a byte that is the start of a UTF-8 character. If not, it returns
1714        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1715        this is necessary because there may be backward assertions in the pattern.
1716        When matching the same subject several times, it may save resources to use
1717        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1719     4. The code for checking the validity of UTF-8 strings has been tightened so
1720        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1721        containing "overlong sequences".
1723     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1724        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1725        should have been "&", but it just so happened that all the cases this let
1726        through by mistake were picked up later in the function.
1728     6. I had used a variable called "isblank" - this is a C99 function, causing
1729        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1731     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1732        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1733        so the version is shown; (c) stop "make test" echoing "./RunTest".
1735     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1737     9. The prototype for memmove() for systems that don't have it was using
1738        size_t, but the inclusion of the header that defines size_t was later. I've
1739        moved the #includes for the C headers earlier to avoid this.
1741    10. Added some adjustments to the code to make it easier to compiler on certain
1742        special systems:
1744          (a) Some "const" qualifiers were missing.
1745          (b) Added the macro EXPORT before all exported functions; by default this
1746              is defined to be empty.
1747          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1748              that it reads its output file name as an argument instead of writing
1749              to the standard output and assuming this can be redirected.
1751    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1752        class containing characters with values greater than 255, PCRE compilation
1753        went into a loop.
1755    12. A recursive reference to a subpattern that was within another subpattern
1756        that had a minimum quantifier of zero caused PCRE to crash. For example,
1757        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1758        recursion. If the recursively-called subpattern itself had a zero repeat,
1759        that was OK.
1761    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1762        buffer into which it was copied (for escape processing) was still set at
1763        1024, so long lines caused crashes.
1765    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1766        "internal error: code overflow...". This applied to any character class
1767        that was followed by a possessive quantifier.
1769    15. Modified the Makefile to add libpcre.la as a prerequisite for
1770        libpcreposix.la because I was told this is needed for a parallel build to
1771        work.
1773    16. If a pattern that contained .* following optional items at the start was
1774        studied, the wrong optimizing data was generated, leading to matching
1775        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1776        matching string must start with a or b or c. The correct conclusion for
1777        this pattern is that a match can start with any character.
1780    Version 4.4 13-Aug-03
1781    ---------------------
1783     1. In UTF-8 mode, a character class containing characters with values between
1784        127 and 255 was not handled correctly if the compiled pattern was studied.
1785        In fixing this, I have also improved the studying algorithm for such
1786        classes (slightly).
1788     2. Three internal functions had redundant arguments passed to them. Removal
1789        might give a very teeny performance improvement.
1791     3. Documentation bug: the value of the capture_top field in a callout is *one
1792        more than* the number of the hightest numbered captured substring.
1794     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1795        in incorrectly linking with a previously installed version. They now link
1796        explicitly with libpcre.la.
1798     5. configure.in no longer needs to recognize Cygwin specially.
1800     6. A problem in pcre.in for Windows platforms is fixed.
1802     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1803        pcretest, it used to include the size of the study block as part of its
1804        output. Unfortunately, the structure contains a field that has a different
1805        size on different hardware architectures. This meant that the tests that
1806        showed this size failed. As the block is currently always of a fixed size,
1807        this information isn't actually particularly useful in pcretest output, so
1808        I have just removed it.
1810     8. Three pre-processor statements accidentally did not start in column 1.
1811        Sadly, there are *still* compilers around that complain, even though
1812        standard C has not required this for well over a decade. Sigh.
1814     9. In pcretest, the code for checking callouts passed small integers in the
1815        callout_data field, which is a void * field. However, some picky compilers
1816        complained about the casts involved for this on 64-bit systems. Now
1817        pcretest passes the address of the small integer instead, which should get
1818        rid of the warnings.
1820    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1821        both compile and run time, and gives an error if an invalid UTF-8 sequence
1822        is found. There is a option for disabling this check in cases where the
1823        string is known to be correct and/or the maximum performance is wanted.
1825    11. In response to a bug report, I changed one line in Makefile.in from
1827            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1828        to
1829            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1831        to look similar to other lines, but I have no way of telling whether this
1832        is the right thing to do, as I do not use Windows. No doubt I'll get told
1833        if it's wrong...
1836    Version 4.3 21-May-03
1837    ---------------------
1839    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1840       Makefile.
1842    2. Some refactoring to improve the quality of the code:
1844       (i)   The utf8_table... variables are now declared "const".
1846       (ii)  The code for \cx, which used the "case flipping" table to upper case
1847             lower case letters, now just substracts 32. This is ASCII-specific,
1848             but the whole concept of \cx is ASCII-specific, so it seems
1849             reasonable.
1851       (iii) PCRE was using its character types table to recognize decimal and
1852             hexadecimal digits in the pattern. This is silly, because it handles
1853             only 0-9, a-f, and A-F, but the character types table is locale-
1854             specific, which means strange things might happen. A private
1855             table is now used for this - though it costs 256 bytes, a table is
1856             much faster than multiple explicit tests. Of course, the standard
1857             character types table is still used for matching digits in subject
1858             strings against \d.
1860       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1861             ending in _t are). So I've renamed it as ESC_tee.
1863    3. The first argument for regexec() in the POSIX wrapper should have been
1864       defined as "const".
1866    4. Changed pcretest to use malloc() for its buffers so that they can be
1867       Electric Fenced for debugging.
1869    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1870       to read one or more bytes before the start of the subject string. Often this
1871       had no effect on PCRE's behaviour, but in some circumstances it could
1872       provoke a segmentation fault.
1874    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1875       to try to read one or more bytes before the start of the subject string.
1877    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1878       UTF-8 support could misbehave in various ways if the subject string
1879       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1880       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1881       back over UTF-8 characters.)
1884    Version 4.2 14-Apr-03
1885    ---------------------
1887    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1889    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1890         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1891         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1892         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1893         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1894           and BUILD_EXEEXT
1895         Note: automatic setting of the BUILD variables is not yet working
1896         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1897           compile-time but not at link-time
1898         [LINK]: use for linking executables only
1899         make different versions for Windows and non-Windows
1900         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1901           libraries
1902         [LINK_FOR_BUILD]: new variable
1903         [OBJEXT]: use throughout
1904         [EXEEXT]: use throughout
1905         <winshared>: new target
1906         <wininstall>: new target
1907         <dftables.o>: use native compiler
1908         <dftables>: use native linker
1909         <install>: handle Windows platform correctly
1910         <clean>: ditto
1911         <check>: ditto
1912         copy DLL to top builddir before testing
1914       As part of these changes, -no-undefined was removed again. This was reported
1915       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1916       in any case.
1918    3. Some tidies to get rid of compiler warnings:
1920       . In the match_data structure, match_limit was an unsigned long int, whereas
1921         match_call_count was an int. I've made them both unsigned long ints.
1923       . In pcretest the fact that a const uschar * doesn't automatically cast to
1924         a void * provoked a warning.
1926       . Turning on some more compiler warnings threw up some "shadow" variables
1927         and a few more missing casts.
1929    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1930       option, a class that contained a single character with a value between 128
1931       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1933    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1934       option, a class that contained several characters, but with at least one
1935       whose value was between 128 and 255 caused PCRE to crash.
1938    Version 4.1 12-Mar-03
1939    ---------------------
1941    1. Compiling with gcc -pedantic found a couple of places where casts were
1942    needed, and a string in dftables.c that was longer than standard compilers are
1943    required to support.
1945    2. Compiling with Sun's compiler found a few more places where the code could
1946    be tidied up in order to avoid warnings.
1948    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1949    first of these names is deprecated in the latest Autoconf in favour of the name
1950    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1951    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1952    analogy I have changed it to CFLAGS_FOR_BUILD.
1954    4. Added -no-undefined to the linking command in the Makefile, because this is
1955    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1956    linking step for the pcreposix library.
1958    5. PCRE was failing to diagnose the case of two named groups with the same
1959    name.
1961    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1962    literal character that is needed in the subject for a match, and scans along to
1963    ensure that it is present before embarking on the full matching process. This
1964    saves time in cases of nested unlimited repeats that are never going to match.
1965    Problem: the scan can take a lot of time if the subject is very long (e.g.
1966    megabytes), thus penalizing straightforward matches. It is now done only if the
1967    amount of subject to be scanned is less than 1000 bytes.
1969    7. A lesser problem with the same optimization is that it was recording the
1970    first character of an anchored pattern as "needed", thus provoking a search
1971    right along the subject, even when the first match of the pattern was going to
1972    fail. The "needed" character is now not set for anchored patterns, unless it
1973    follows something in the pattern that is of non-fixed length. Thus, it still
1974    fulfils its original purpose of finding quick non-matches in cases of nested
1975    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1978    Version 4.0 17-Feb-03
1979    ---------------------
1981    1. If a comment in an extended regex that started immediately after a meta-item
1982    extended to the end of string, PCRE compiled incorrect data. This could lead to
1983    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1985    2. Moved to autoconf 2.53 and libtool 1.4.2.
1987    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1988    the special perltest8 script is no longer needed - all the tests can be run
1989    from a single perltest script.
1991    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1992    by \s. It has now been removed in PCRE. This means it isn't recognized as
1993    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1994    class [:space:] *does* include VT, thereby creating a mess.
1996    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1997    space and tab.
1999    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2000    its new features into the main test script, reducing the number of scripts.
2002    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2003    were backward compatible, and made the (?i) apply to the whole pattern, as if
2004    /i were given. Now it behaves more logically, and applies the option setting
2005    only to what follows. PCRE has been changed to follow suit. However, if it
2006    finds options settings right at the start of the pattern, it extracts them into
2007    the global options, as before. Thus, they show up in the info data.
2009    8. Added support for the \Q...\E escape sequence. Characters in between are
2010    treated as literals. This is slightly different from Perl in that $ and @ are
2011    also handled as literals inside the quotes. In Perl, they will cause variable
2012    interpolation. Note the following examples:
2014        Pattern            PCRE matches      Perl matches
2016        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2017        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2018        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2020    For compatibility with Perl, \Q...\E sequences are recognized inside character
2021    classes as well as outside them.
2023    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2024    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2025    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2026    signed/unsigned warnings.
2028    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2029    option for pcretest, so I've replaced it by a simple function that does just
2030    that job.
2032    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2033    "pcregrep -".
2035    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2036    Java package. This provides some syntactic sugar for simple cases of what my
2037    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2038    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2039    item, you can use this simplified notation. Note that only makes sense with
2040    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2041    greediness, whatever the setting of the PCRE_UNGREEDY option.
2043    13. A change of greediness default within a pattern was not taking effect at
2044    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2045    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2046    was abstracted outside.
2048    14. PCRE now supports the \G assertion. It is true when the current matching
2049    position is at the start point of the match. This differs from \A when the
2050    starting offset is non-zero. Used with the /g option of pcretest (or similar
2051    code), it works in the same way as it does for Perl's /g option. If all
2052    alternatives of a regex begin with \G, the expression is anchored to the start
2053    match position, and the "anchored" flag is set in the compiled expression.
2055    15. Some bugs concerning the handling of certain option changes within patterns
2056    have been fixed. These applied to options other than (?ims). For example,
2057    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2058    been the other way round. Some of this was related to change 7 above.
2060    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2061    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2062    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2063    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2065    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2066    mode. Unlike ".", it always matches newline, whatever the setting of
2067    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2068    assertions. Perl allows it, but it doesn't (in general) work because it can't
2069    calculate the length of the lookbehind. At least, that's the case for Perl
2070    5.8.0 - I've been told they are going to document that it doesn't work in
2071    future.
2073    18. Added an error diagnosis for escapes that PCRE does not support: these are
2074    \L, \l, \N, \P, \p, \U, \u, and \X.
2076    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2077    reading past the end of the pattern in cases such as /[abcd/.
2079    20. PCRE was getting more memory than necessary for patterns with classes that
2080    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2082    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2083    compiling PCRE for use with Virtual Pascal.
2085    22. Small fix to the Makefile to make it work properly if the build is done
2086    outside the source tree.
2088    23. Added a new extension: a condition to go with recursion. If a conditional
2089    subpattern starts with (?(R) the "true" branch is used if recursion has
2090    happened, whereas the "false" branch is used only at the top level.
2092    24. When there was a very long string of literal characters (over 255 bytes
2093    without UTF support, over 250 bytes with UTF support), the computation of how
2094    much memory was required could be incorrect, leading to segfaults or other
2095    strange effects.
2097    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2098    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2099    there was a subsequent back reference to those brackets. This meant that, for
2100    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2101    possible to check for precisely this case. All we can do is abandon the
2102    optimization if .* occurs inside capturing brackets when there are any back
2103    references whatsoever. (See below for a better fix that came later.)
2105    26. The handling of the optimization for finding the first character of a
2106    non-anchored pattern, and for finding a character that is required later in the
2107    match were failing in some cases. This didn't break the matching; it just
2108    failed to optimize when it could. The way this is done has been re-implemented.
2110    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2112    28. Added a new feature that provides some of the functionality that Perl
2113    provides with (?{...}). The facility is termed a "callout". The way it is done
2114    in PCRE is for the caller to provide an optional function, by setting
2115    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2116    global variable. By default it is unset, which disables all calling out. To get
2117    the function called, the regex must include (?C) at appropriate points. This
2118    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2119    This provides a means of identifying different callout points. When PCRE
2120    reaches such a point in the regex, if pcre_callout has been set, the external
2121    function is called. It is provided with data in a structure called
2122    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2123    matching continues; if it returns a non-zero value, the match at the current
2124    point fails. However, backtracking will occur if possible. [This was changed
2125    later and other features added - see item 49 below.]
2127    29. pcretest is upgraded to test the callout functionality. It provides a
2128    callout function that displays information. By default, it shows the start of
2129    the match and the current position in the text. There are some new data escapes
2130    to vary what happens:
2132        \C+         in addition, show current contents of captured substrings
2133        \C-         do not supply a callout function
2134        \C!n        return 1 when callout number n is reached
2135        \C!n!m      return 1 when callout number n is reached for the mth time
2137    30. If pcregrep was called with the -l option and just a single file name, it
2138    output "<stdin>" if a match was found, instead of the file name.
2140    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2141    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2142    pcre_exec(). This saves a malloc/free per call. The default value of
2143    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2144    when configuring.
2146    32. The default maximum size of a compiled pattern is 64K. There have been a
2147    few cases of people hitting this limit. The code now uses macros to handle the
2148    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2149    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2150    configuring. Tests 2 and 5 work only with 2-byte links because they output
2151    debugging information about compiled patterns.
2153    33. Internal code re-arrangements:
2155    (a) Moved the debugging function for printing out a compiled regex into
2156        its own source file (printint.c) and used #include to pull it into
2157        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2158        separate copies.
2160    (b) Defined the list of op-code names for debugging as a macro in
2161        internal.h so that it is next to the definition of the opcodes.
2163    (c) Defined a table of op-code lengths for simpler skipping along compiled
2164        code. This is again a macro in internal.h so that it is next to the
2165        definition of the opcodes.
2167    34. Added support for recursive calls to individual subpatterns, along the
2168    lines of Robin Houston's patch (but implemented somewhat differently).
2170    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2171    allow it to read and process whole directories in Win32. This code was
2172    contributed by Lionel Fourquaux; it has not been tested by me.
2174    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2175    used to name a group. Names consist of alphanumerics and underscores, and must
2176    be unique. Back references use the syntax (?P=name) and recursive calls use
2177    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2178    numbers. The function pcre_fullinfo() can be used after compilation to extract
2179    a name/number map. There are three relevant calls:
2181      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2182      PCRE_INFO_NAMECOUNT            yields the number of entries
2183      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2185    The map is a vector of fixed-size entries. The size of each entry depends on
2186    the length of the longest name used. The first two bytes of each entry are the
2187    group number, most significant byte first. There follows the corresponding
2188    name, zero terminated. The names are in alphabetical order.
2190    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2191    case instead of 255. Making it the same both with and without UTF-8 support
2192    means that the same test output works with both.
2194    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2195    calling malloc() with a zero argument.
2197    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2198    optimization. I've improved things by keeping a bitmap of backreferences with
2199    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2200    fact referenced, the optimization can be applied. It is unlikely that a
2201    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2202    the match to follow \n) will appear inside brackets with a number greater than
2203    31, but if it does, any back reference > 31 suppresses the optimization.
2205    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2206    of disabling numbered capturing parentheses. Any opening parenthesis that is
2207    not followed by ? behaves as if it were followed by ?: but named parentheses
2208    can still be used for capturing (and they will acquire numbers in the usual
2209    way).
2211    41. Redesigned the return codes from the match() function into yes/no/error so
2212    that errors can be passed back from deep inside the nested calls. A malloc
2213    failure while inside a recursive subpattern call now causes the
2214    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2216    42. It is now possible to set a limit on the number of times the match()
2217    function is called in a call to pcre_exec(). This facility makes it possible to
2218    limit the amount of recursion and backtracking, though not in a directly
2219    obvious way, because the match() function is used in a number of different
2220    circumstances. The count starts from zero for each position in the subject
2221    string (for non-anchored patterns). The default limit is, for compatibility, a
2222    large number, namely 10 000 000. You can change this in two ways:
2224    (a) When configuring PCRE before making, you can use --with-match-limit=n
2225        to set a default value for the compiled library.
2227    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2228        a different value is set. See 45 below.
2230    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2232    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2233    of things that can be changed at compile time. The first argument specifies
2234    what is wanted and the second points to where the information is to be placed.
2235    The current list of available information is:
2237      PCRE_CONFIG_UTF8
2239    The output is an integer that is set to one if UTF-8 support is available;
2240    otherwise it is set to zero.
2244    The output is an integer that it set to the value of the code that is used for
2245    newline. It is either LF (10) or CR (13).
2249    The output is an integer that contains the number of bytes used for internal
2250    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2254    The output is an integer that contains the threshold above which the POSIX
2255    interface uses malloc() for output vectors. See item 31 above.
2259    The output is an unsigned integer that contains the default limit of the number
2260    of match() calls in a pcre_exec() execution. See 42 above.
2262    44. pcretest has been upgraded by the addition of the -C option. This causes it
2263    to extract all the available output from the new pcre_config() function, and to
2264    output it. The program then exits immediately.
2266    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2267    order to support additional features. One way would have been to define
2268    pcre_exec2() (for example) with extra arguments, but this would not have been
2269    extensible, and would also have required all calls to the original function to
2270    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2271    is used for passing in "extra" data from pcre_study().
2273    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2274    contains the following fields:
2276      flags         a bitmap indicating which of the following fields are set
2277      study_data    opaque data from pcre_study()
2278      match_limit   a way of specifying a limit on match() calls for a specific
2279                      call to pcre_exec()
2280      callout_data  data for callouts (see 49 below)
2282    The flag bits are also defined in pcre.h, and are
2288    The pcre_study() function now returns one of these new pcre_extra blocks, with
2289    the actual study data pointed to by the study_data field, and the
2290    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2291    before. That is, this change is entirely upwards-compatible and requires no
2292    change to existing code.
2294    If you want to pass in additional data to pcre_exec(), you can either place it
2295    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2296    block.
2298    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2299    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2300    times with different match limits, until it finds the minimum value needed for
2301    pcre_exec() to complete. The value is then output. This can be instructive; for
2302    most simple matches the number is quite small, but for pathological cases it
2303    gets very large very quickly.
2305    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2306    returns the size of the data block pointed to by the study_data field in a
2307    pcre_extra block, that is, the value that was passed as the argument to
2308    pcre_malloc() when PCRE was getting memory in which to place the information
2309    created by pcre_study(). The fourth argument should point to a size_t variable.
2310    pcretest has been extended so that this information is shown after a successful
2311    pcre_study() call when information about the compiled regex is being displayed.
2313    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2314    because what follows is always an absolute path. (Later: it turns out that this
2315    is more than cosmetic for MinGW, because it doesn't like empty path
2316    components.)
2318    49. Some changes have been made to the callout feature (see 28 above):
2320    (i)  A callout function now has three choices for what it returns:
2322           0  =>  success, carry on matching
2323         > 0  =>  failure at this point, but backtrack if possible
2324         < 0  =>  serious error, return this value from pcre_exec()
2326         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2327         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2328         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2329         use by callout functions. It will never be used by PCRE itself.
2331    (ii) The pcre_extra structure (see 45 above) has a void * field called
2332         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2333         pcre_callout_block structure has a field of the same name. The contents of
2334         the field passed in the pcre_extra structure are passed to the callout
2335         function in the corresponding field in the callout block. This makes it
2336         easier to use the same callout-containing regex from multiple threads. For
2337         testing, the pcretest program has a new data escape
2339           \C*n        pass the number n (may be negative) as callout_data
2341         If the callout function in pcretest receives a non-zero value as
2342         callout_data, it returns that value.
2344    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2345    there were some redundant $(CFLAGS) in commands that are now specified as
2346    $(LINK), which already includes $(CFLAGS).
2348    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2349    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2350    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2351    one-byte characters throughout. Note that case-insensitive matching applies
2352    only to characters whose values are less than 256. PCRE doesn't support the
2353    notion of cases for higher-valued characters.
2355    (i)   A character class whose characters are all within 0-255 is handled as
2356          a bit map, and the map is inverted for negative classes. Previously, a
2357          character > 255 always failed to match such a class; however it should
2358          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2360    (ii)  A negated character class with a single character < 255 is coded as
2361          "not this character" (OP_NOT). This wasn't working properly when the test
2362          character was multibyte, either singly or repeated.
2364    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2365          mode, for example: \x{100}{2,3}.
2367    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2368          singly or repeated) now correctly test multibyte characters. However,
2369          PCRE doesn't recognize any characters with values greater than 255 as
2370          digits, spaces, or word characters. Such characters always match \D, \S,
2371          and \W, and never match \d, \s, or \w.
2373    (v)   Classes may now contain characters and character ranges with values
2374          greater than 255. For example: [ab\x{100}-\x{400}].
2376    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2377          PCRE in UTF-8 mode.
2379    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2380    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2381    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2382    value.)
2384    53. The single man page has become too large. I have therefore split it up into
2385    a number of separate man pages. These also give rise to individual HTML pages;
2386    these are now put in a separate directory, and there is an index.html page that
2387    lists them all. Some hyperlinking between the pages has been installed.
2389    54. Added convenience functions for handling named capturing parentheses.
2391    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2392    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2393    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2394    are faulted.
2396    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2397    calling configure. These values are used when compiling the dftables.c program
2398    which is run to generate the source of the default character tables. They
2399    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2400    you will need to set these values.
2402    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2405    Version 3.9 02-Jan-02
2406    ---------------------
2408    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2410    2. If --disable-static was given, the building process failed when trying to
2411    build pcretest and pcregrep. (For some reason it was using libtool to compile
2412    them, which is not right, as they aren't part of the library.)
2415    Version 3.8 18-Dec-01
2416    ---------------------
2418    1. The experimental UTF-8 code was completely screwed up. It was packing the
2419    bytes in the wrong order. How dumb can you get?
2422    Version 3.7 29-Oct-01
2423    ---------------------
2425    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2426    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2427    this didn't happen under Solaris 8, where I normally test things.
2429    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2430    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2431    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2432    this fix an hour or so after the initial 3.7 release.)
2435    Version 3.6 23-Oct-01
2436    ---------------------
2438    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2439    offsets passed as NULL with zero offset count.
2441    2. The config.guess and config.sub files had not been updated when I moved to
2442    the latest autoconf.
2445    Version 3.5 15-Aug-01
2446    ---------------------
2448    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2449    had been forgotten.
2451    2. By using declared but undefined structures, we can avoid using "void"
2452    definitions in pcre.h while keeping the internal definitions of the structures
2453    private.
2455    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2456    user point of view, this means that both static and shared libraries are built
2457    by default, but this can be individually controlled. More of the work of
2458    handling this static/shared cases is now inside libtool instead of PCRE's make
2459    file.
2461    4. The pcretest utility is now installed along with pcregrep because it is
2462    useful for users (to test regexs) and by doing this, it automatically gets
2463    relinked by libtool. The documentation has been turned into a man page, so
2464    there are now .1, .txt, and .html versions in /doc.
2466    5. Upgrades to pcregrep:
2467       (i)   Added long-form option names like gnu grep.
2468       (ii)  Added --help to list all options with an explanatory phrase.
2469       (iii) Added -r, --recursive to recurse into sub-directories.
2470       (iv)  Added -f, --file to read patterns from a file.
2472    6. pcre_exec() was referring to its "code" argument before testing that
2473    argument for NULL (and giving an error if it was NULL).
2475    7. Upgraded Makefile.in to allow for compiling in a different directory from
2476    the source directory.
2478    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2479    options bits, the pointer it was passed was to an int instead of to an unsigned
2480    long int. This mattered only on 64-bit systems.
2482    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2483    generated) instead of pcre.in, which it its source. Also made the same change
2484    in several of the .c files.
2486    10. A new release of gcc defines printf() as a macro, which broke pcretest
2487    because it had an ifdef in the middle of a string argument for printf(). Fixed
2488    by using separate calls to printf().
2490    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2491    script, to force use of CR or LF instead of \n in the source. On non-Unix
2492    systems, the value can be set in config.h.
2494    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2495    absolute limit. Changed the text of the error message to make this clear, and
2496    likewise updated the man page.
2498    13. The limit of 99 on the number of capturing subpatterns has been removed.
2499    The new limit is 65535, which I hope will not be a "real" limit.
2502    Version 3.4 22-Aug-00
2503    ---------------------
2505    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2507    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2510    Version 3.3 01-Aug-00
2511    ---------------------
2513    1. If an octal character was given, but the value was greater than \377, it
2514    was not getting masked to the least significant bits, as documented. This could
2515    lead to crashes in some systems.
2517    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2518    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2520    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2521    These just pass their arguments on to (pcre_free)(), but they are provided
2522    because some uses of PCRE bind it to non-C systems that can call its functions,
2523    but cannot call free() or pcre_free() directly.
2525    4. Add "make test" as a synonym for "make check". Corrected some comments in
2526    the Makefile.
2528    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2529    Makefile.
2531    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2532    command called pgrep for grepping around the active processes.
2534    7. Added the beginnings of support for UTF-8 character strings.
2536    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2537    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2538    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2539    out for the ar command.)
2542    Version 3.2 12-May-00
2543    ---------------------
2545    This is purely a bug fixing release.
2547    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2548    of ZA. This was just one example of several cases that could provoke this bug,
2549    which was introduced by change 9 of version 2.00. The code for breaking
2550    infinite loops after an iteration that matches an empty string was't working
2551    correctly.
2553    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2554    when matched against abbab (for example). After matching an empty string, it
2555    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2556    caused it to match further down the string than it should.
2558    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2559    was there because it doesn't seem to be needed, and it causes trouble on some
2560    systems, as it is not a Standard C header. It has been removed.
2562    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2563    were reported on the Macintosh. The changes were from
2565      while ((c = *(++ptr)) != 0 && c != '\n');
2566    to
2567      while ((c = *(++ptr)) != 0 && c != '\n') ;
2569    Totally extraordinary, but if that's what it takes...
2571    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2572    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2573    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2574    assumes the way PCRE uses memmove() (always moving upwards).
2576    6. PCRE is being used in one environment where strchr() is not available. There
2577    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2578    faster code anyway.
2581    Version 3.1 09-Feb-00
2582    ---------------------
2584    The only change in this release is the fixing of some bugs in Makefile.in for
2585    the "install" target:
2587    (1) It was failing to install pcreposix.h.
2589    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2592    Version 3.0 01-Feb-00
2593    ---------------------
2595    1. Add support for the /+ modifier to perltest (to output $` like it does in
2596    pcretest).
2598    2. Add support for the /g modifier to perltest.
2600    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2601    matches null strings.
2603    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2604    pattern. Perl treats empty patterns specially - it reuses the most recent
2605    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2606    effect.
2608    5. The POSIX interface was broken in that it was just handing over the POSIX
2609    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2610    required a bigger vector, with some working space on the end. This means that
2611    the POSIX wrapper now has to get and free some memory, and copy the results.
2613    6. Added some simple autoconf support, placing the test data and the
2614    documentation in separate directories, re-organizing some of the
2615    information files, and making it build pcre-config (a GNU standard). Also added
2616    libtool support for building PCRE as a shared library, which is now the
2617    default.
2619    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2620    09 are not valid octal constants. Single digits will be used for minor values
2621    less than 10.
2623    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2624    existing programs that set these in the POSIX interface can use PCRE without
2625    modification.
2627    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2628    return all that pcre_info() returns, plus additional data. The pcre_info()
2629    function is retained for compatibility, but is considered to be obsolete.
2631    10. Added experimental recursion feature (?R) to handle one common case that
2632    Perl 5.6 will be able to do with (?p{...}).
2634    11. Added support for POSIX character classes like [:alpha:], which Perl is
2635    adopting.
2638    Version 2.08 31-Aug-99
2639    ----------------------
2641    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2642    trying to match at the startoffset position, but instead was moving forward to
2643    the next newline as if a previous match had failed.
2645    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2646    and could get into a loop if a null string was matched other than at the start
2647    of the subject.
2649    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2650    be distinguished at compile time, and for completeness also added PCRE_DATE.
2652    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2653    in GnuWin32 environments.
2656    Version 2.07 29-Jul-99
2657    ----------------------
2659    1. The documentation is now supplied in plain text form and HTML as well as in
2660    the form of man page sources.
2662    2. C++ compilers don't like assigning (void *) values to other pointer types.
2663    In particular this affects malloc(). Although there is no problem in Standard
2664    C, I've put in casts to keep C++ compilers happy.
2666    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2667    should be (const char *).
2669    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2670    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2671    However, I haven't made this a standard facility. The documentation doesn't
2672    mention it, and the Makefile doesn't support it.
2674    5. The Makefile now contains an "install" target, with editable destinations at
2675    the top of the file. The pcretest program is not installed.
2677    6. pgrep -V now gives the PCRE version number and date.
2679    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2680    causing the entire string to be ignored, instead of just the last character.
2682    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2683    non-matching string, it can take a very, very long time, even for strings of
2684    quite modest length, because of the nested recursion. PCRE now does better in
2685    some of these cases. It does this by remembering the last required literal
2686    character in the pattern, and pre-searching the subject to ensure it is present
2687    before running the real match. In other words, it applies a heuristic to detect
2688    some types of certain failure quickly, and in the above example, if presented
2689    with a string that has no trailing " it gives "no match" very quickly.
2691    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2692    other alternatives are tried instead.
2695    Version 2.06 09-Jun-99
2696    ----------------------
2698    1. Change pcretest's output for amount of store used to show just the code
2699    space, because the remainder (the data block) varies in size between 32-bit and
2700    64-bit systems.
2702    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2703    start matching at. This allows lookbehinds to work when searching for multiple
2704    occurrences in a string.
2706    3. Added additional options to pcretest for testing multiple occurrences:
2708       /+   outputs the rest of the string that follows a match
2709       /g   loops for multiple occurrences, using the new startoffset argument
2710       /G   loops for multiple occurrences by passing an incremented pointer
2712    4. PCRE wasn't doing the "first character" optimization for patterns starting
2713    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2714    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2715    the letter 'x'. On long subject strings, this gives a significant speed-up.
2718    Version 2.05 21-Apr-99
2719    ----------------------
2721    1. Changed the type of magic_number from int to long int so that it works
2722    properly on 16-bit systems.
2724    2. Fixed a bug which caused patterns starting with .* not to work correctly
2725    when the subject string contained newline characters. PCRE was assuming
2726    anchoring for such patterns in all cases, which is not correct because .* will
2727    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2728    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2729    must be retried after every newline in the subject.
2732  Version 2.04 18-Feb-99  Version 2.04 18-Feb-99
2733  ----------------------  ----------------------

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