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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.4 10-Sep-07
5    ---------------------
6    
7    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8        means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
13    
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
19    
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
25    
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
28    
29    5.  doc/pcresyntax.html was missing from the distribution.
30    
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
33    
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
36        windows.h file is present (where different names are used).
37    
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
40    
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
43    
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
49    
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
55    
56        Thanks to the folks working on Gregex for glib for this insight.
57    
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
60    
61    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
62    
63    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
64        checked only for CRLF.
65    
66    
67    Version 7.3 28-Aug-07
68    ---------------------
69    
70     1. In the rejigging of the build system that eventually resulted in 7.1, the
71        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
72        brackets there is not right, since it causes compilers to look for an
73        installed pcre.h, not the version that is in the source that is being
74        compiled (which of course may be different). I have changed it back to:
75    
76          #include "pcre.h"
77    
78        I have a vague recollection that the change was concerned with compiling in
79        different directories, but in the new build system, that is taken care of
80        by the VPATH setting the Makefile.
81    
82     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
83        when the subject happened to end in the byte 0x85 (e.g. if the last
84        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
85        characters but of course it shouldn't be taken as a newline when it is part
86        of another character. The bug was that, for an unlimited repeat of . in
87        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
88        characters when looking for a newline.
89    
90     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
91    
92     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
93        in debug output.
94    
95     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
96        long printing in the pcrecpp unittest when running under MinGW.
97    
98     6. ESC_K was left out of the EBCDIC table.
99    
100     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
101        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
102        limit also applies to "virtual nesting" when a pattern is recursive, and in
103        this case 1000 isn't so big. I have been able to remove this limit at the
104        expense of backing off one optimization in certain circumstances. Normally,
105        when pcre_exec() would call its internal match() function recursively and
106        immediately return the result unconditionally, it uses a "tail recursion"
107        feature to save stack. However, when a subpattern that can match an empty
108        string has an unlimited repetition quantifier, it no longer makes this
109        optimization. That gives it a stack frame in which to save the data for
110        checking that an empty string has been matched. Previously this was taken
111        from the 1000-entry workspace that had been reserved. So now there is no
112        explicit limit, but more stack is used.
113    
114     8. Applied Daniel's patches to solve problems with the import/export magic
115        syntax that is required for Windows, and which was going wrong for the
116        pcreposix and pcrecpp parts of the library. These were overlooked when this
117        problem was solved for the main library.
118    
119     9. There were some crude static tests to avoid integer overflow when computing
120        the size of patterns that contain repeated groups with explicit upper
121        limits. As the maximum quantifier is 65535, the maximum group length was
122        set at 30,000 so that the product of these two numbers did not overflow a
123        32-bit integer. However, it turns out that people want to use groups that
124        are longer than 30,000 bytes (though not repeat them that many times).
125        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
126        made it possible to implement the integer overflow checks in a much more
127        dynamic way, which I have now done. The artificial limitation on group
128        length has been removed - we now have only the limit on the total length of
129        the compiled pattern, which depends on the LINK_SIZE setting.
130    
131    10. Fixed a bug in the documentation for get/copy named substring when
132        duplicate names are permitted. If none of the named substrings are set, the
133        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
134        empty string.
135    
136    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
137        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
138        because the ] is interpreted as the first data character and the
139        terminating ] is not found. PCRE has been made compatible with Perl in this
140        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
141        cause memory overwriting.
142    
143    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
144        string has been matched (to stop an infinite loop). It was not recognizing
145        a conditional subpattern that could match an empty string if that
146        subpattern was within another subpattern. For example, it looped when
147        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
148        condition was not nested. This bug has been fixed.
149    
150    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
151        past the start of the subject in the presence of bytes with the top bit
152        set, for example "\x8aBCD".
153    
154    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
155        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
156    
157    14. Optimized (?!) to (*FAIL).
158    
159    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
160        This restricts code points to be within the range 0 to 0x10FFFF, excluding
161        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
162        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
163        does: it's just the validity check that is more restrictive.
164    
165    16. Inserted checks for integer overflows during escape sequence (backslash)
166        processing, and also fixed erroneous offset values for syntax errors during
167        backslash processing.
168    
169    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
170        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
171    
172    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
173        caused an overrun.
174    
175    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
176        something other than just ASCII characters) inside a group that had an
177        unlimited repeat caused a loop at compile time (while checking to see
178        whether the group could match an empty string).
179    
180    20. Debugging a pattern containing \p or \P could cause a crash. For example,
181        [\P{Any}] did so. (Error in the code for printing property names.)
182    
183    21. An orphan \E inside a character class could cause a crash.
184    
185    22. A repeated capturing bracket such as (A)? could cause a wild memory
186        reference during compilation.
187    
188    23. There are several functions in pcre_compile() that scan along a compiled
189        expression for various reasons (e.g. to see if it's fixed length for look
190        behind). There were bugs in these functions when a repeated \p or \P was
191        present in the pattern. These operators have additional parameters compared
192        with \d, etc, and these were not being taken into account when moving along
193        the compiled data. Specifically:
194    
195        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
196            length.
197    
198        (b) An item such as \pL+ within a repeated group could cause crashes or
199            loops.
200    
201        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
202            "reference to non-existent subpattern" error.
203    
204        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
205    
206    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
207        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
208    
209    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
210    
211    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
212        character were causing crashes (broken optimization).
213    
214    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
215        \p or \P) caused a compile-time loop.
216    
217    28. More problems have arisen in unanchored patterns when CRLF is a valid line
218        break. For example, the unstudied pattern [\r\n]A does not match the string
219        "\r\nA" because change 7.0/46 below moves the current point on by two
220        characters after failing to match at the start. However, the pattern \nA
221        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
222        the same is true. There doesn't seem any very clean way out of this, but
223        what I have chosen to do makes the common cases work: PCRE now takes note
224        of whether there can be an explicit match for \r or \n anywhere in the
225        pattern, and if so, 7.0/46 no longer applies. As part of this change,
226        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
227        pattern has explicit CR or LF references.
228    
229    29. Added (*CR) etc for changing newline setting at start of pattern.
230    
231    
232    Version 7.2 19-Jun-07
233    ---------------------
234    
235     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
236        which is apparently normally available under Windows.
237    
238     2. Re-jig the pcregrep tests with different newline settings in an attempt
239        to make them independent of the local environment's newline setting.
240    
241     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
242    
243     4. Some of the "internals" tests were previously cut out when the link size
244        was not 2, because the output contained actual offsets. The recent new
245        "Z" feature of pcretest means that these can be cut out, making the tests
246        usable with all link sizes.
247    
248     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
249        stack recursion. This gives a massive performance boost under BSD, but just
250        a small improvement under Linux. However, it saves one field in the frame
251        in all cases.
252    
253     6. Added more features from the forthcoming Perl 5.10:
254    
255        (a) (?-n) (where n is a string of digits) is a relative subroutine or
256            recursion call. It refers to the nth most recently opened parentheses.
257    
258        (b) (?+n) is also a relative subroutine call; it refers to the nth next
259            to be opened parentheses.
260    
261        (c) Conditions that refer to capturing parentheses can be specified
262            relatively, for example, (?(-2)... or (?(+3)...
263    
264        (d) \K resets the start of the current match so that everything before
265            is not part of it.
266    
267        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
268    
269        (f) \g{name} is another synonym - part of Perl 5.10's unification of
270            reference syntax.
271    
272        (g) (?| introduces a group in which the numbering of parentheses in each
273            alternative starts with the same number.
274    
275        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
276    
277     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
278        PCRE_INFO_JCHANGED.
279    
280     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
281        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
282        for detecting groups that can match an empty string.
283    
284     9. A pattern with a very large number of alternatives (more than several
285        hundred) was running out of internal workspace during the pre-compile
286        phase, where pcre_compile() figures out how much memory will be needed. A
287        bit of new cunning has reduced the workspace needed for groups with
288        alternatives. The 1000-alternative test pattern now uses 12 bytes of
289        workspace instead of running out of the 4096 that are available.
290    
291    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
292    
293    11. Applied patch from Google to remove an optimization that didn't quite work.
294        The report of the bug said:
295    
296          pcrecpp::RE("a*").FullMatch("aaa") matches, while
297          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
298          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
299    
300    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
301        it matched the wrong number of bytes.
302    
303    
304    Version 7.1 24-Apr-07
305    ---------------------
306    
307     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
308        that is more "standard", making use of automake and other Autotools. There
309        is some re-arrangement of the files and adjustment of comments consequent
310        on this.
311    
312     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
313        for recursive directory scanning broke on some systems because the files
314        are not scanned in any specific order and on different systems the order
315        was different. A call to "sort" has been inserted into RunGrepTest for the
316        approprate test as a short-term fix. In the longer term there may be an
317        alternative.
318    
319     3. I had an email from Eric Raymond about problems translating some of PCRE's
320        man pages to HTML (despite the fact that I distribute HTML pages, some
321        people do their own conversions for various reasons). The problems
322        concerned the use of low-level troff macros .br and .in. I have therefore
323        removed all such uses from the man pages (some were redundant, some could
324        be replaced by .nf/.fi pairs). The 132html script that I use to generate
325        HTML has been updated to handle .nf/.fi and to complain if it encounters
326        .br or .in.
327    
328     4. Updated comments in configure.ac that get placed in config.h.in and also
329        arranged for config.h to be included in the distribution, with the name
330        config.h.generic, for the benefit of those who have to compile without
331        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
332    
333     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
334        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
335        makevp.bat for the current PCRE, using the additional files
336        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
337    
338     6. A Windows user reported a minor discrepancy with test 2, which turned out
339        to be caused by a trailing space on an input line that had got lost in his
340        copy. The trailing space was an accident, so I've just removed it.
341    
342     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
343        that is needed.
344    
345     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
346        as "const" (a) because they are and (b) because it helps the PHP
347        maintainers who have recently made a script to detect big data structures
348        in the php code that should be moved to the .rodata section. I remembered
349        to update Builducptable as well, so it won't revert if ucptable.h is ever
350        re-created.
351    
352     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
353        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
354        order to be able to cut out the UTF-8 tables in the latter when UTF-8
355        support is not required. This saves 1.5-2K of code, which is important in
356        some applications.
357    
358        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
359        so as not to refer to the tables, even though these functions will never be
360        called when UTF-8 support is disabled. Otherwise there are problems with a
361        shared library.
362    
363    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
364    
365        (a) It was defining its arguments as char * instead of void *.
366    
367        (b) It was assuming that all moves were upwards in memory; this was true
368            a long time ago when I wrote it, but is no longer the case.
369    
370        The emulated memove() is provided for those environments that have neither
371        memmove() nor bcopy(). I didn't think anyone used it these days, but that
372        is clearly not the case, as these two bugs were recently reported.
373    
374    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
375        and Detrail to create the HTML documentation, the .txt form of the man
376        pages, and it removes trailing spaces from listed files. It also creates
377        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
378        case, it wraps all the #defines with #ifndefs. This script should be run
379        before "make dist".
380    
381    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
382        with Unicode property support.
383    
384        (a) For a maximizing quantifier, if the two different cases of the
385            character were of different lengths in their UTF-8 codings (there are
386            some cases like this - I found 11), and the matching function had to
387            back up over a mixture of the two cases, it incorrectly assumed they
388            were both the same length.
389    
390        (b) When PCRE was configured to use the heap rather than the stack for
391            recursion during matching, it was not correctly preserving the data for
392            the other case of a UTF-8 character when checking ahead for a match
393            while processing a minimizing repeat. If the check also involved
394            matching a wide character, but failed, corruption could cause an
395            erroneous result when trying to check for a repeat of the original
396            character.
397    
398    13. Some tidying changes to the testing mechanism:
399    
400        (a) The RunTest script now detects the internal link size and whether there
401            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
402            values substituted by "configure". (The RunGrepTest script already did
403            this for UTF-8.) The configure.ac script no longer substitutes the
404            relevant variables.
405    
406        (b) The debugging options /B and /D in pcretest show the compiled bytecode
407            with length and offset values. This means that the output is different
408            for different internal link sizes. Test 2 is skipped for link sizes
409            other than 2 because of this, bypassing the problem. Unfortunately,
410            there was also a test in test 3 (the locale tests) that used /B and
411            failed for link sizes other than 2. Rather than cut the whole test out,
412            I have added a new /Z option to pcretest that replaces the length and
413            offset values with spaces. This is now used to make test 3 independent
414            of link size. (Test 2 will be tidied up later.)
415    
416    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
417        segmentation fault instead of returning the appropriate error message.
418    
419    15. In multiline mode when the newline sequence was set to "any", the pattern
420        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
421        This doesn't seem right; it now treats the CRLF combination as the line
422        ending, and so does not match in that case. It's only a pattern such as ^$
423        that would hit this one: something like ^ABC$ would have failed after \r
424        and then tried again after \r\n.
425    
426    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
427        in an attempt to make files that differ only in their line terminators
428        compare equal. This works on Linux.
429    
430    17. Under certain error circumstances pcregrep might try to free random memory
431        as it exited. This is now fixed, thanks to valgrind.
432    
433    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
434        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
435        was because its rules for how to advance for /g after matching an empty
436        string at the end of a line did not allow for this case. They now check for
437        it specially.
438    
439    20. pcretest is supposed to handle patterns and data of any length, by
440        extending its buffers when necessary. It was getting this wrong when the
441        buffer for a data line had to be extended.
442    
443    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
444        CRLF as a newline sequence.
445    
446    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
447        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
448        I have nevertheless tidied it up.
449    
450    23. Added some casts to kill warnings from HP-UX ia64 compiler.
451    
452    24. Added a man page for pcre-config.
453    
454    
455    Version 7.0 19-Dec-06
456    ---------------------
457    
458     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
459        moving to gcc 4.1.1.
460    
461     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
462        sys/time.h, which is documented as needed for this function. It doesn't
463        seem to matter on Linux, but it showed up on some releases of OS X.
464    
465     3. It seems that there are systems where bytes whose values are greater than
466        127 match isprint() in the "C" locale. The "C" locale should be the
467        default when a C program starts up. In most systems, only ASCII printing
468        characters match isprint(). This difference caused the output from pcretest
469        to vary, making some of the tests fail. I have changed pcretest so that:
470    
471        (a) When it is outputting text in the compiled version of a pattern, bytes
472            other than 32-126 are always shown as hex escapes.
473    
474        (b) When it is outputting text that is a matched part of a subject string,
475            it does the same, unless a different locale has been set for the match
476            (using the /L modifier). In this case, it uses isprint() to decide.
477    
478     4. Fixed a major bug that caused incorrect computation of the amount of memory
479        required for a compiled pattern when options that changed within the
480        pattern affected the logic of the preliminary scan that determines the
481        length. The relevant options are -x, and -i in UTF-8 mode. The result was
482        that the computed length was too small. The symptoms of this bug were
483        either the PCRE error "internal error: code overflow" from pcre_compile(),
484        or a glibc crash with a message such as "pcretest: free(): invalid next
485        size (fast)". Examples of patterns that provoked this bug (shown in
486        pcretest format) are:
487    
488          /(?-x: )/x
489          /(?x)(?-x: \s*#\s*)/
490          /((?i)[\x{c0}])/8
491          /(?i:[\x{c0}])/8
492    
493        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
494        is now done differently.
495    
496     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
497        wrapper classes; (b) implement a new function in the C++ scanner that is
498        more efficient than the old way of doing things because it avoids levels of
499        recursion in the regex matching; (c) add a paragraph to the documentation
500        for the FullMatch() function.
501    
502     6. The escape sequence \n was being treated as whatever was defined as
503        "newline". Not only was this contrary to the documentation, which states
504        that \n is character 10 (hex 0A), but it also went horribly wrong when
505        "newline" was defined as CRLF. This has been fixed.
506    
507     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
508        was being set to -1 for the "end of line" case (supposedly a value that no
509        character can have). Though this value is never used (the check for end of
510        line is "zero bytes in current character"), it caused compiler complaints.
511        I've changed it to 0xffffffff.
512    
513     8. In pcre_version.c, the version string was being built by a sequence of
514        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
515        string (as it is for production releases) called a macro with an empty
516        argument. The C standard says the result of this is undefined. The gcc
517        compiler treats it as an empty string (which was what was wanted) but it is
518        reported that Visual C gives an error. The source has been hacked around to
519        avoid this problem.
520    
521     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
522        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
523        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
524        of them did).
525    
526    10. Originally, pcretest opened its input and output without "b"; then I was
527        told that "b" was needed in some environments, so it was added for release
528        5.0 to both the input and output. (It makes no difference on Unix-like
529        systems.) Later I was told that it is wrong for the input on Windows. I've
530        now abstracted the modes into two macros, to make it easier to fiddle with
531        them, and removed "b" from the input mode under Windows.
532    
533    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
534    
535    12. Added -help and --help to pcretest as an official way of being reminded
536        of the options.
537    
538    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
539        and pcrecpp.cc because they annoy compilers at high warning levels.
540    
541    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
542    
543    15. Fixed an occurrence of == in configure.ac that should have been = (shell
544        scripts are not C programs :-) and which was not noticed because it works
545        on Linux.
546    
547    16. pcretest is supposed to handle any length of pattern and data line (as one
548        line or as a continued sequence of lines) by extending its input buffer if
549        necessary. This feature was broken for very long pattern lines, leading to
550        a string of junk being passed to pcre_compile() if the pattern was longer
551        than about 50K.
552    
553    17. I have done a major re-factoring of the way pcre_compile() computes the
554        amount of memory needed for a compiled pattern. Previously, there was code
555        that made a preliminary scan of the pattern in order to do this. That was
556        OK when PCRE was new, but as the facilities have expanded, it has become
557        harder and harder to keep it in step with the real compile phase, and there
558        have been a number of bugs (see for example, 4 above). I have now found a
559        cunning way of running the real compile function in a "fake" mode that
560        enables it to compute how much memory it would need, while actually only
561        ever using a few hundred bytes of working memory and without too many
562        tests of the mode. This should make future maintenance and development
563        easier. A side effect of this work is that the limit of 200 on the nesting
564        depth of parentheses has been removed (though this was never a serious
565        limitation, I suspect). However, there is a downside: pcre_compile() now
566        runs more slowly than before (30% or more, depending on the pattern). I
567        hope this isn't a big issue. There is no effect on runtime performance.
568    
569    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
570        newline (only possible for the last line of a file) and it was a
571        pattern that set a locale (followed by /Lsomething), pcretest crashed.
572    
573    19. Added additional timing features to pcretest. (1) The -tm option now times
574        matching only, not compiling. (2) Both -t and -tm can be followed, as a
575        separate command line item, by a number that specifies the number of
576        repeats to use when timing. The default is 50000; this gives better
577        precision, but takes uncomfortably long for very large patterns.
578    
579    20. Extended pcre_study() to be more clever in cases where a branch of a
580        subpattern has no definite first character. For example, (a*|b*)[cd] would
581        previously give no result from pcre_study(). Now it recognizes that the
582        first character must be a, b, c, or d.
583    
584    21. There was an incorrect error "recursive call could loop indefinitely" if
585        a subpattern (or the entire pattern) that was being tested for matching an
586        empty string contained only one non-empty item after a nested subpattern.
587        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
588        incorrectly, because the \d was being skipped in the check.
589    
590    22. The pcretest program now has a new pattern option /B and a command line
591        option -b, which is equivalent to adding /B to every pattern. This causes
592        it to show the compiled bytecode, without the additional information that
593        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
594        is the same as /B/I).
595    
596    23. A new optimization is now able automatically to treat some sequences such
597        as a*b as a*+b. More specifically, if something simple (such as a character
598        or a simple class like \d) has an unlimited quantifier, and is followed by
599        something that cannot possibly match the quantified thing, the quantifier
600        is automatically "possessified".
601    
602    24. A recursive reference to a subpattern whose number was greater than 39
603        went wrong under certain circumstances in UTF-8 mode. This bug could also
604        have affected the operation of pcre_study().
605    
606    25. Realized that a little bit of performance could be had by replacing
607        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
608    
609    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
610    
611    27. Possessive quantifiers such as a++ were previously implemented by turning
612        them into atomic groups such as ($>a+). Now they have their own opcodes,
613        which improves performance. This includes the automatically created ones
614        from 23 above.
615    
616    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
617        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
618        the first matched character to be a colon. This applied both to named and
619        numbered groups.
620    
621    29. The ucpinternal.h header file was missing its idempotency #ifdef.
622    
623    30. I was sent a "project" file called libpcre.a.dev which I understand makes
624        building PCRE on Windows easier, so I have included it in the distribution.
625    
626    31. There is now a check in pcretest against a ridiculously large number being
627        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
628        loop, the loop is abandoned.
629    
630    32. Forward references to subpatterns in conditions such as (?(2)...) where
631        subpattern 2 is defined later cause pcre_compile() to search forwards in
632        the pattern for the relevant set of parentheses. This search went wrong
633        when there were unescaped parentheses in a character class, parentheses
634        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
635    
636    33. "Subroutine" calls and backreferences were previously restricted to
637        referencing subpatterns earlier in the regex. This restriction has now
638        been removed.
639    
640    34. Added a number of extra features that are going to be in Perl 5.10. On the
641        whole, these are just syntactic alternatives for features that PCRE had
642        previously implemented using the Python syntax or my own invention. The
643        other formats are all retained for compatibility.
644    
645        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
646            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
647            also .NET compatible.
648    
649        (b) A recursion or subroutine call to a named group can now be defined as
650            (?&name) as well as (?P>name).
651    
652        (c) A backreference to a named group can now be defined as \k<name> or
653            \k'name' as well as (?P=name). The new forms, as well as being in Perl
654            5.10, are also .NET compatible.
655    
656        (d) A conditional reference to a named group can now use the syntax
657            (?(<name>) or (?('name') as well as (?(name).
658    
659        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
660            groups (named and numbered) that are never evaluated inline, but can be
661            called as "subroutines" from elsewhere. In effect, the DEFINE condition
662            is always false. There may be only one alternative in such a group.
663    
664        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
665            as the simple (?(R). The condition is true only if the most recent
666            recursion is that of the given number or name. It does not search out
667            through the entire recursion stack.
668    
669        (g) The escape \gN or \g{N} has been added, where N is a positive or
670            negative number, specifying an absolute or relative reference.
671    
672    35. Tidied to get rid of some further signed/unsigned compiler warnings and
673        some "unreachable code" warnings.
674    
675    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
676        things, this adds five new scripts.
677    
678    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
679        There were also incompatibilities regarding the handling of \Q..\E inside
680        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
681        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
682    
683    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
684        matches an empty string, and forcibly breaks the loop. There were bugs in
685        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
686        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
687        separate and independent bugs (that affected different cases) have been
688        fixed.
689    
690    39. Refactored the code to abolish the use of different opcodes for small
691        capturing bracket numbers. This is a tidy that I avoided doing when I
692        removed the limit on the number of capturing brackets for 3.5 back in 2001.
693        The new approach is not only tidier, it makes it possible to reduce the
694        memory needed to fix the previous bug (38).
695    
696    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
697        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
698        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
699        mode.
700    
701    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
702        report.
703    
704    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
705        copy construction and assignment in the C++ wrapper.
706    
707    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
708        couple of bugs that could have given wrong results in the "--newline=crlf"
709        case.
710    
711    44. Added a number of casts and did some reorganization of signed/unsigned int
712        variables following suggestions from Dair Grant. Also renamed the variable
713        "this" as "item" because it is a C++ keyword.
714    
715    45. Arranged for dftables to add
716    
717          #include "pcre_internal.h"
718    
719        to pcre_chartables.c because without it, gcc 4.x may remove the array
720        definition from the final binary if PCRE is built into a static library and
721        dead code stripping is activated.
722    
723    46. For an unanchored pattern, if a match attempt fails at the start of a
724        newline sequence, and the newline setting is CRLF or ANY, and the next two
725        characters are CRLF, advance by two characters instead of one.
726    
727    
728    Version 6.7 04-Jul-06
729    ---------------------
730    
731     1. In order to handle tests when input lines are enormously long, pcretest has
732        been re-factored so that it automatically extends its buffers when
733        necessary. The code is crude, but this _is_ just a test program. The
734        default size has been increased from 32K to 50K.
735    
736     2. The code in pcre_study() was using the value of the re argument before
737        testing it for NULL. (Of course, in any sensible call of the function, it
738        won't be NULL.)
739    
740     3. The memmove() emulation function in pcre_internal.h, which is used on
741        systems that lack both memmove() and bcopy() - that is, hardly ever -
742        was missing a "static" storage class specifier.
743    
744     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
745        containing an extended class (one that cannot be represented by a bitmap
746        because it contains high-valued characters or Unicode property items, e.g.
747        [\pZ]). Almost always one would set UTF-8 mode when processing such a
748        pattern, but PCRE should not loop if you do not (it no longer does).
749        [Detail: two cases were found: (a) a repeated subpattern containing an
750        extended class; (b) a recursive reference to a subpattern that followed a
751        previous extended class. It wasn't skipping over the extended class
752        correctly when UTF-8 mode was not set.]
753    
754     5. A negated single-character class was not being recognized as fixed-length
755        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
756        compile error "lookbehind assertion is not fixed length".
757    
758     6. The RunPerlTest auxiliary script was showing an unexpected difference
759        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
760        write a Perl script that can interpret lines of an input file either as
761        byte characters or as UTF-8, which is what "perltest" was being required to
762        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
763        can't do is switch easily at run time between having the "use utf8;" pragma
764        or not. In the end, I fudged it by using the RunPerlTest script to insert
765        "use utf8;" explicitly for the UTF-8 tests.
766    
767     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
768        the end of the subject string, contrary to the documentation and to what
769        Perl does. This was true of both matching functions. Now it matches only at
770        the start of the subject and immediately after *internal* newlines.
771    
772     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
773        a pointer to an int instead of a pointer to an unsigned long int. This
774        caused problems on 64-bit systems.
775    
776     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
777        instance of the 'standard' template library not being so standard".
778    
779    10. There was no check on the number of named subpatterns nor the maximum
780        length of a subpattern name. The product of these values is used to compute
781        the size of the memory block for a compiled pattern. By supplying a very
782        long subpattern name and a large number of named subpatterns, the size
783        computation could be caused to overflow. This is now prevented by limiting
784        the length of names to 32 characters, and the number of named subpatterns
785        to 10,000.
786    
787    11. Subpatterns that are repeated with specific counts have to be replicated in
788        the compiled pattern. The size of memory for this was computed from the
789        length of the subpattern and the repeat count. The latter is limited to
790        65535, but there was no limit on the former, meaning that integer overflow
791        could in principle occur. The compiled length of a repeated subpattern is
792        now limited to 30,000 bytes in order to prevent this.
793    
794    12. Added the optional facility to have named substrings with the same name.
795    
796    13. Added the ability to use a named substring as a condition, using the
797        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
798        are numbers (not recommended). Forward references are permitted.
799    
800    14. Added forward references in named backreferences (if you see what I mean).
801    
802    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
803        pattern could run off the end of the subject. For example, the pattern
804        "(?s)(.{1,5})"8 did this with the subject "ab".
805    
806    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
807        PCRE_CASELESS was set when matching characters that were quantified with ?
808        or *.
809    
810    17. A character class other than a single negated character that had a minimum
811        but no maximum quantifier - for example [ab]{6,} - was not handled
812        correctly by pce_dfa_exec(). It would match only one character.
813    
814    18. A valid (though odd) pattern that looked like a POSIX character
815        class but used an invalid character after [ (for example [[,abc,]]) caused
816        pcre_compile() to give the error "Failed: internal error: code overflow" or
817        in some cases to crash with a glibc free() error. This could even happen if
818        the pattern terminated after [[ but there just happened to be a sequence of
819        letters, a binary zero, and a closing ] in the memory that followed.
820    
821    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
822        over the years. Originally (before any Unicode support), just the bottom 8
823        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
824        output from "man perlunicode" includes this:
825    
826          The regular expression compiler produces polymorphic opcodes.  That
827          is, the pattern adapts to the data and automatically switches to
828          the Unicode character scheme when presented with Unicode data--or
829          instead uses a traditional byte scheme when presented with byte
830          data.
831    
832        Sadly, a wide octal escape does not cause a switch, and in a string with
833        no other multibyte characters, these octal escapes are treated as before.
834        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
835        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
836        Unicode string.
837    
838        I have not perpetrated such confusion in PCRE. Up till now, it took just
839        the bottom 8 bits, as in old Perl. I have now made octal escapes with
840        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
841        translate to the appropriate multibyte character.
842    
843    29. Applied some refactoring to reduce the number of warnings from Microsoft
844        and Borland compilers. This has included removing the fudge introduced
845        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
846        a warning about an unused variable.
847    
848    21. PCRE has not included VT (character 0x0b) in the set of whitespace
849        characters since release 4.0, because Perl (from release 5.004) does not.
850        [Or at least, is documented not to: some releases seem to be in conflict
851        with the documentation.] However, when a pattern was studied with
852        pcre_study() and all its branches started with \s, PCRE still included VT
853        as a possible starting character. Of course, this did no harm; it just
854        caused an unnecessary match attempt.
855    
856    22. Removed a now-redundant internal flag bit that recorded the fact that case
857        dependency changed within the pattern. This was once needed for "required
858        byte" processing, but is no longer used. This recovers a now-scarce options
859        bit. Also moved the least significant internal flag bit to the most-
860        significant bit of the word, which was not previously used (hangover from
861        the days when it was an int rather than a uint) to free up another bit for
862        the future.
863    
864    23. Added support for CRLF line endings as well as CR and LF. As well as the
865        default being selectable at build time, it can now be changed at runtime
866        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
867        specify that it is scanning data with non-default line endings.
868    
869    24. Changed the definition of CXXLINK to make it agree with the definition of
870        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
871    
872    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
873        recursions. This makes a big different to stack usage for some patterns.
874    
875    26. If a subpattern containing a named recursion or subroutine reference such
876        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
877        the space required for the compiled pattern went wrong and gave too small a
878        value. Depending on the environment, this could lead to "Failed: internal
879        error: code overflow at offset 49" or "glibc detected double free or
880        corruption" errors.
881    
882    27. Applied patches from Google (a) to support the new newline modes and (b) to
883        advance over multibyte UTF-8 characters in GlobalReplace.
884    
885    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
886        difference for some implementation of PCRE in some Windows version.
887    
888    29. Added some extra testing facilities to pcretest:
889    
890        \q<number>   in a data line sets the "match limit" value
891        \Q<number>   in a data line sets the "match recursion limt" value
892        -S <number>  sets the stack size, where <number> is in megabytes
893    
894        The -S option isn't available for Windows.
895    
896    
897    Version 6.6 06-Feb-06
898    ---------------------
899    
900     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
901        in pcreposix.h. I have copied the definition from pcre.h.
902    
903     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
904        because pcre.h is no longer a built file.
905    
906     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
907        not normally included in the compiled code.
908    
909    
910    Version 6.5 01-Feb-06
911    ---------------------
912    
913     1. When using the partial match feature with pcre_dfa_exec(), it was not
914        anchoring the second and subsequent partial matches at the new starting
915        point. This could lead to incorrect results. For example, with the pattern
916        /1234/, partially matching against "123" and then "a4" gave a match.
917    
918     2. Changes to pcregrep:
919    
920        (a) All non-match returns from pcre_exec() were being treated as failures
921            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
922            error message is output. Some extra information is given for the
923            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
924            probably the only errors that are likely to be caused by users (by
925            specifying a regex that has nested indefinite repeats, for instance).
926            If there are more than 20 of these errors, pcregrep is abandoned.
927    
928        (b) A binary zero was treated as data while matching, but terminated the
929            output line if it was written out. This has been fixed: binary zeroes
930            are now no different to any other data bytes.
931    
932        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
933            used to set a locale for matching. The --locale=xxxx long option has
934            been added (no short equivalent) to specify a locale explicitly on the
935            pcregrep command, overriding the environment variables.
936    
937        (d) When -B was used with -n, some line numbers in the output were one less
938            than they should have been.
939    
940        (e) Added the -o (--only-matching) option.
941    
942        (f) If -A or -C was used with -c (count only), some lines of context were
943            accidentally printed for the final match.
944    
945        (g) Added the -H (--with-filename) option.
946    
947        (h) The combination of options -rh failed to suppress file names for files
948            that were found from directory arguments.
949    
950        (i) Added the -D (--devices) and -d (--directories) options.
951    
952        (j) Added the -F (--fixed-strings) option.
953    
954        (k) Allow "-" to be used as a file name for -f as well as for a data file.
955    
956        (l) Added the --colo(u)r option.
957    
958        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
959            is not present by default.
960    
961     3. A nasty bug was discovered in the handling of recursive patterns, that is,
962        items such as (?R) or (?1), when the recursion could match a number of
963        alternatives. If it matched one of the alternatives, but subsequently,
964        outside the recursion, there was a failure, the code tried to back up into
965        the recursion. However, because of the way PCRE is implemented, this is not
966        possible, and the result was an incorrect result from the match.
967    
968        In order to prevent this happening, the specification of recursion has
969        been changed so that all such subpatterns are automatically treated as
970        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
971    
972     4. I had overlooked the fact that, in some locales, there are characters for
973        which isalpha() is true but neither isupper() nor islower() are true. In
974        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
975        and ordfeminine) are like this. This affected the treatment of \w and \W
976        when they appeared in character classes, but not when they appeared outside
977        a character class. The bit map for "word" characters is now created
978        separately from the results of isalnum() instead of just taking it from the
979        upper, lower, and digit maps. (Plus the underscore character, of course.)
980    
981     5. The above bug also affected the handling of POSIX character classes such as
982        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
983        permanent tables. Instead, the bit maps for such a class were previously
984        created as the appropriate unions of the upper, lower, and digit bitmaps.
985        Now they are created by subtraction from the [[:word:]] class, which has
986        its own bitmap.
987    
988     6. The [[:blank:]] character class matches horizontal, but not vertical space.
989        It is created by subtracting the vertical space characters (\x09, \x0a,
990        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
991        subtraction was done in the overall bitmap for a character class, meaning
992        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
993        be recognized. This bug has been fixed.
994    
995     7. Patches from the folks at Google:
996    
997          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
998          real life, but is still worth protecting against".
999    
1000          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1001          regular expressions".
1002    
1003          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1004          have it.
1005    
1006          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1007          "configure" and the latter not, in order to fix a problem somebody had
1008          with compiling the Arg class on HP-UX.
1009    
1010          (e) Improve the error-handling of the C++ wrapper a little bit.
1011    
1012          (f) New tests for checking recursion limiting.
1013    
1014     8. The pcre_memmove() function, which is used only if the environment does not
1015        have a standard memmove() function (and is therefore rarely compiled),
1016        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1017        returning a result (though PCRE never actually uses the result).
1018    
1019     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1020        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1021        returned instead of calling malloc() with an overflowing number that would
1022        most likely cause subsequent chaos.
1023    
1024    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1025    
1026    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1027        with this option is matched, the nmatch and pmatch options of regexec() are
1028        ignored.
1029    
1030    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1031        provided in case anyone wants to the the POSIX interface with UTF-8
1032        strings.
1033    
1034    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1035        C++ linking (needed for some HP-UX environments).
1036    
1037    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1038        (unused parameter) and in the pcre_printint() function (omitted "default"
1039        switch label when the default is to do nothing).
1040    
1041    15. Added some code to make it possible, when PCRE is compiled as a C++
1042        library, to replace subject pointers for pcre_exec() with a smart pointer
1043        class, thus making it possible to process discontinuous strings.
1044    
1045    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1046        much the same function. They were added by different people who were trying
1047        to make PCRE easy to compile on non-Unix systems. It has been suggested
1048        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1049        for compiling on Windows systems. I have therefore replaced it with
1050        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1051        defaults to "extern" for C or "extern C" for C++, which works fine on
1052        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1053        SCOPE with something explicit in config.h. In addition:
1054    
1055        (a) pcreposix.h still had just "extern" instead of either of these macros;
1056            I have replaced it with PCRE_DATA_SCOPE.
1057    
1058        (b) Functions such as _pcre_xclass(), which are internal to the library,
1059            but external in the C sense, all had PCRE_EXPORT in their definitions.
1060            This is apparently wrong for the Windows case, so I have removed it.
1061            (It makes no difference on Unix-like systems.)
1062    
1063    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1064        of recursive calls to match(). This is different to MATCH_LIMIT because
1065        that limits the total number of calls to match(), not all of which increase
1066        the depth of recursion. Limiting the recursion depth limits the amount of
1067        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1068        when PCRE is compiled, and changed at run time. A patch from Google adds
1069        this functionality to the C++ interface.
1070    
1071    18. Changes to the handling of Unicode character properties:
1072    
1073        (a) Updated the table to Unicode 4.1.0.
1074    
1075        (b) Recognize characters that are not in the table as "Cn" (undefined).
1076    
1077        (c) I revised the way the table is implemented to a much improved format
1078            which includes recognition of ranges. It now supports the ranges that
1079            are defined in UnicodeData.txt, and it also amalgamates other
1080            characters into ranges. This has reduced the number of entries in the
1081            table from around 16,000 to around 3,000, thus reducing its size
1082            considerably. I realized I did not need to use a tree structure after
1083            all - a binary chop search is just as efficient. Having reduced the
1084            number of entries, I extended their size from 6 bytes to 8 bytes to
1085            allow for more data.
1086    
1087        (d) Added support for Unicode script names via properties such as \p{Han}.
1088    
1089    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1090        matching that character.
1091    
1092    20. When matching a repeated Unicode property with a minimum greater than zero,
1093        (for example \pL{2,}), PCRE could look past the end of the subject if it
1094        reached it while seeking the minimum number of characters. This could
1095        happen only if some of the characters were more than one byte long, because
1096        there is a check for at least the minimum number of bytes.
1097    
1098    21. Refactored the implementation of \p and \P so as to be more general, to
1099        allow for more different types of property in future. This has changed the
1100        compiled form incompatibly. Anybody with saved compiled patterns that use
1101        \p or \P will have to recompile them.
1102    
1103    22. Added "Any" and "L&" to the supported property types.
1104    
1105    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1106        but give a compile time error if the value is greater than 0xff.
1107    
1108    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1109        accidentally not being installed or uninstalled.
1110    
1111    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1112        made were to insert the current release number. This seemed silly, because
1113        it made things harder for people building PCRE on systems that don't run
1114        "configure". I have turned pcre.h into a distributed file, no longer built
1115        by "configure", with the version identification directly included. There is
1116        no longer a pcre.h.in file.
1117    
1118        However, this change necessitated a change to the pcre-config script as
1119        well. It is built from pcre-config.in, and one of the substitutions was the
1120        release number. I have updated configure.ac so that ./configure now finds
1121        the release number by grepping pcre.h.
1122    
1123    26. Added the ability to run the tests under valgrind.
1124    
1125    
1126    Version 6.4 05-Sep-05
1127    ---------------------
1128    
1129     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1130        "--" to be printed when multiple files were scanned, even when none of the
1131        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1132        consider it to be a bug, and have restored the previous behaviour.
1133    
1134     2. A couple of code tidies to get rid of compiler warnings.
1135    
1136     3. The pcretest program used to cheat by referring to symbols in the library
1137        whose names begin with _pcre_. These are internal symbols that are not
1138        really supposed to be visible externally, and in some environments it is
1139        possible to suppress them. The cheating is now confined to including
1140        certain files from the library's source, which is a bit cleaner.
1141    
1142     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1143        file's purpose clearer.
1144    
1145     5. Reorganized pcre_ucp_findchar().
1146    
1147    
1148    Version 6.3 15-Aug-05
1149    ---------------------
1150    
1151     1. The file libpcre.pc.in did not have general read permission in the tarball.
1152    
1153     2. There were some problems when building without C++ support:
1154    
1155        (a) If C++ support was not built, "make install" and "make test" still
1156            tried to test it.
1157    
1158        (b) There were problems when the value of CXX was explicitly set. Some
1159            changes have been made to try to fix these, and ...
1160    
1161        (c) --disable-cpp can now be used to explicitly disable C++ support.
1162    
1163        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1164            backslash in a target when C++ was disabled. This confuses some
1165            versions of "make", apparently. Using an intermediate variable solves
1166            this. (Same for CPP_LOBJ.)
1167    
1168     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1169        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1170        necessary on certain architectures.
1171    
1172     4. Added a setting of -export-symbols-regex to the link command to remove
1173        those symbols that are exported in the C sense, but actually are local
1174        within the library, and not documented. Their names all begin with
1175        "_pcre_". This is not a perfect job, because (a) we have to except some
1176        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1177        available (and never for static libraries). I have made a note to try to
1178        find a way round (a) in the future.
1179    
1180    
1181    Version 6.2 01-Aug-05
1182    ---------------------
1183    
1184     1. There was no test for integer overflow of quantifier values. A construction
1185        such as {1111111111111111} would give undefined results. What is worse, if
1186        a minimum quantifier for a parenthesized subpattern overflowed and became
1187        negative, the calculation of the memory size went wrong. This could have
1188        led to memory overwriting.
1189    
1190     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1191    
1192     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1193        operating environments where this matters.
1194    
1195     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1196        PCRE options from within the C++ wrapper.
1197    
1198     5. Named capturing subpatterns were not being correctly counted when a pattern
1199        was compiled. This caused two problems: (a) If there were more than 100
1200        such subpatterns, the calculation of the memory needed for the whole
1201        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1202        back references of the form \12, where the number was greater than 9, were
1203        not recognized as back references, even though there were sufficient
1204        previous subpatterns.
1205    
1206     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1207        versions of gcc, e.g. 2.95.4.
1208    
1209    
1210    Version 6.1 21-Jun-05
1211    ---------------------
1212    
1213     1. There was one reference to the variable "posix" in pcretest.c that was not
1214        surrounded by "#if !defined NOPOSIX".
1215    
1216     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1217        the cross-check on the old pcre_info() function, for the benefit of the
1218        cut-down version of PCRE that is currently imported into Exim.
1219    
1220     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1221        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1222        patterns that start (?i) but I don't think that matters. The use of (?i) is
1223        just an example; this all applies to the other options as well.
1224    
1225     4. Since libtool seems to echo the compile commands it is issuing, the output
1226        from "make" can be reduced a bit by putting "@" in front of each libtool
1227        compile command.
1228    
1229     5. Patch from the folks at Google for configure.in to be a bit more thorough
1230        in checking for a suitable C++ installation before trying to compile the
1231        C++ stuff. This should fix a reported problem when a compiler was present,
1232        but no suitable headers.
1233    
1234     6. The man pages all had just "PCRE" as their title. I have changed them to
1235        be the relevant file name. I have also arranged that these names are
1236        retained in the file doc/pcre.txt, which is a concatenation in text format
1237        of all the man pages except the little individual ones for each function.
1238    
1239     7. The NON-UNIX-USE file had not been updated for the different set of source
1240        files that come with release 6. I also added a few comments about the C++
1241        wrapper.
1242    
1243    
1244    Version 6.0 07-Jun-05
1245    ---------------------
1246    
1247     1. Some minor internal re-organization to help with my DFA experiments.
1248    
1249     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1250        didn't matter for the library itself when fully configured, but did matter
1251        when compiling without UCP support, or within Exim, where the ucp files are
1252        not imported.
1253    
1254     3. Refactoring of the library code to split up the various functions into
1255        different source modules. The addition of the new DFA matching code (see
1256        below) to a single monolithic source would have made it really too
1257        unwieldy, quite apart from causing all the code to be include in a
1258        statically linked application, when only some functions are used. This is
1259        relevant even without the DFA addition now that patterns can be compiled in
1260        one application and matched in another.
1261    
1262        The downside of splitting up is that there have to be some external
1263        functions and data tables that are used internally in different modules of
1264        the library but which are not part of the API. These have all had their
1265        names changed to start with "_pcre_" so that they are unlikely to clash
1266        with other external names.
1267    
1268     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1269        a different (DFA) algorithm. Although it is slower than the original
1270        function, it does have some advantages for certain types of matching
1271        problem.
1272    
1273     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1274        including restarting after a partial match.
1275    
1276     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1277        defined when compiling for Windows was sent to me. I have put it into the
1278        code, though I have no means of testing or verifying it.
1279    
1280     7. Added the pcre_refcount() auxiliary function.
1281    
1282     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1283        match before or at the first newline in the subject string. In pcretest,
1284        the /f option on a pattern can be used to set this.
1285    
1286     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1287        would behave wrongly. This has been present in PCRE since release 4.0.
1288    
1289    10. A number of changes to the pcregrep command:
1290    
1291        (a) Refactored how -x works; insert ^(...)$ instead of setting
1292            PCRE_ANCHORED and checking the length, in preparation for adding
1293            something similar for -w.
1294    
1295        (b) Added the -w (match as a word) option.
1296    
1297        (c) Refactored the way lines are read and buffered so as to have more
1298            than one at a time available.
1299    
1300        (d) Implemented a pcregrep test script.
1301    
1302        (e) Added the -M (multiline match) option. This allows patterns to match
1303            over several lines of the subject. The buffering ensures that at least
1304            8K, or the rest of the document (whichever is the shorter) is available
1305            for matching (and similarly the previous 8K for lookbehind assertions).
1306    
1307        (f) Changed the --help output so that it now says
1308    
1309              -w, --word-regex(p)
1310    
1311            instead of two lines, one with "regex" and the other with "regexp"
1312            because that confused at least one person since the short forms are the
1313            same. (This required a bit of code, as the output is generated
1314            automatically from a table. It wasn't just a text change.)
1315    
1316        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1317            option but starts with a hyphen. Could be a pattern or a path name
1318            starting with a hyphen, for instance.
1319    
1320        (h) "-" can be given as a file name to represent stdin.
1321    
1322        (i) When file names are being printed, "(standard input)" is used for
1323            the standard input, for compatibility with GNU grep. Previously
1324            "<stdin>" was used.
1325    
1326        (j) The option --label=xxx can be used to supply a name to be used for
1327            stdin when file names are being printed. There is no short form.
1328    
1329        (k) Re-factored the options decoding logic because we are going to add
1330            two more options that take data. Such options can now be given in four
1331            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1332    
1333        (l) Added the -A, -B, and -C options for requesting that lines of context
1334            around matches be printed.
1335    
1336        (m) Added the -L option to print the names of files that do not contain
1337            any matching lines, that is, the complement of -l.
1338    
1339        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1340            continue to scan other files.
1341    
1342        (o) The -s option was incorrectly implemented. For compatibility with other
1343            greps, it now suppresses the error message for a non-existent or non-
1344            accessible file (but not the return code). There is a new option called
1345            -q that suppresses the output of matching lines, which was what -s was
1346            previously doing.
1347    
1348        (p) Added --include and --exclude options to specify files for inclusion
1349            and exclusion when recursing.
1350    
1351    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1352        Hopefully, it now does.
1353    
1354    12. Missing cast in pcre_study().
1355    
1356    13. Added an "uninstall" target to the makefile.
1357    
1358    14. Replaced "extern" in the function prototypes in Makefile.in with
1359        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1360        world, but is set differently for Windows.
1361    
1362    15. Added a second compiling function called pcre_compile2(). The only
1363        difference is that it has an extra argument, which is a pointer to an
1364        integer error code. When there is a compile-time failure, this is set
1365        non-zero, in addition to the error test pointer being set to point to an
1366        error message. The new argument may be NULL if no error number is required
1367        (but then you may as well call pcre_compile(), which is now just a
1368        wrapper). This facility is provided because some applications need a
1369        numeric error indication, but it has also enabled me to tidy up the way
1370        compile-time errors are handled in the POSIX wrapper.
1371    
1372    16. Added VPATH=.libs to the makefile; this should help when building with one
1373        prefix path and installing with another. (Or so I'm told by someone who
1374        knows more about this stuff than I do.)
1375    
1376    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1377        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1378        match everything, including newlines. This is not POSIX-compatible, but
1379        somebody wanted the feature. From pcretest it can be activated by using
1380        both the P and the s flags.
1381    
1382    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1383    
1384    19. libpcre.pc was being incorrectly installed as executable.
1385    
1386    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1387        it now also looks for '\r' so that it will work unmodified on Windows.
1388    
1389    21. Added Google's contributed C++ wrapper to the distribution.
1390    
1391    22. Added some untidy missing memory free() calls in pcretest, to keep
1392        Electric Fence happy when testing.
1393    
1394    
1395    
1396    Version 5.0 13-Sep-04
1397    ---------------------
1398    
1399     1. Internal change: literal characters are no longer packed up into items
1400        containing multiple characters in a single byte-string. Each character
1401        is now matched using a separate opcode. However, there may be more than one
1402        byte in the character in UTF-8 mode.
1403    
1404     2. The pcre_callout_block structure has two new fields: pattern_position and
1405        next_item_length. These contain the offset in the pattern to the next match
1406        item, and its length, respectively.
1407    
1408     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1409        insertion of callouts before each pattern item. Added the /C option to
1410        pcretest to make use of this.
1411    
1412     4. On the advice of a Windows user, the lines
1413    
1414          #if defined(_WIN32) || defined(WIN32)
1415          _setmode( _fileno( stdout ), 0x8000 );
1416          #endif  /* defined(_WIN32) || defined(WIN32) */
1417    
1418        have been added to the source of pcretest. This apparently does useful
1419        magic in relation to line terminators.
1420    
1421     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1422        for the benefit of those environments where the "b" makes a difference.
1423    
1424     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1425        to know about it. I have put a hack into configure.in that adds in code
1426        to set GCC=yes if CC=icc. This seems to end up at a point in the
1427        generated configure script that is early enough to affect the setting of
1428        compiler options, which is what is needed, but I have no means of testing
1429        whether it really works. (The user who reported this had patched the
1430        generated configure script, which of course I cannot do.)
1431    
1432        LATER: After change 22 below (new libtool files), the configure script
1433        seems to know about icc (and also ecc). Therefore, I have commented out
1434        this hack in configure.in.
1435    
1436     7. Added support for pkg-config (2 patches were sent in).
1437    
1438     8. Negated POSIX character classes that used a combination of internal tables
1439        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1440        [[:^ascii]]. Typically, they would match almost any characters. The other
1441        POSIX classes were not broken in this way.
1442    
1443     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1444        to find the match, as PCRE was deluded into thinking that the match had to
1445        start at the start point or following a newline. The same bug applied to
1446        patterns with negative forward assertions or any backward assertions
1447        preceding ".*" at the start, unless the pattern required a fixed first
1448        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1449    
1450    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1451        starting at the last subject character, bytes beyond the end of the subject
1452        string were read.
1453    
1454    11. Renamed the variable "class" as "classbits" to make life easier for C++
1455        users. (Previously there was a macro definition, but it apparently wasn't
1456        enough.)
1457    
1458    12. Added the new field "tables" to the extra data so that tables can be passed
1459        in at exec time, or the internal tables can be re-selected. This allows
1460        a compiled regex to be saved and re-used at a later time by a different
1461        program that might have everything at different addresses.
1462    
1463    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1464        -R library as well as a -L library.
1465    
1466    14. The debugging options of pcretest (-d on the command line or D on a
1467        pattern) showed incorrect output for anything following an extended class
1468        that contained multibyte characters and which was followed by a quantifier.
1469    
1470    15. Added optional support for general category Unicode character properties
1471        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1472        support. It adds about 90K to the size of the library. The meanings of the
1473        inbuilt class escapes such as \d and \s have NOT been changed.
1474    
1475    16. Updated pcredemo.c to include calls to free() to release the memory for the
1476        compiled pattern.
1477    
1478    17. The generated file chartables.c was being created in the source directory
1479        instead of in the building directory. This caused the build to fail if the
1480        source directory was different from the building directory, and was
1481        read-only.
1482    
1483    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1484        file. No doubt somebody will tell me if they don't make sense... Also added
1485        Dan Mooney's comments about building on OpenVMS.
1486    
1487    19. Added support for partial matching via the PCRE_PARTIAL option for
1488        pcre_exec() and the \P data escape in pcretest.
1489    
1490    20. Extended pcretest with 3 new pattern features:
1491    
1492        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1493              write the compiled pattern to the file whose name is "rest-of-line".
1494              This is a straight binary dump of the data, with the saved pointer to
1495              the character tables forced to be NULL. The study data, if any, is
1496              written too. After writing, pcretest reads a new pattern.
1497    
1498        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1499              compiled pattern from the given file. There must not be any
1500              occurrences of "<" in the file name (pretty unlikely); if there are,
1501              pcretest will instead treat the initial "<" as a pattern delimiter.
1502              After reading in the pattern, pcretest goes on to read data lines as
1503              usual.
1504    
1505        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1506              and 16-bit fields in a compiled pattern, to simulate a pattern that
1507              was compiled on a host of opposite endianness.
1508    
1509    21. The pcre-exec() function can now cope with patterns that were compiled on
1510        hosts of opposite endianness, with this restriction:
1511    
1512          As for any compiled expression that is saved and used later, the tables
1513          pointer field cannot be preserved; the extra_data field in the arguments
1514          to pcre_exec() should be used to pass in a tables address if a value
1515          other than the default internal tables were used at compile time.
1516    
1517    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1518        now diagnosed as an error. Previously, most of the time, a negative number
1519        would have been treated as zero, but if in addition "ovector" was passed as
1520        NULL, a crash could occur.
1521    
1522    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1523        new versions from the libtool 1.5 distribution (the last one is a copy of
1524        a file called libtool.m4). This seems to have fixed the need to patch
1525        "configure" to support Darwin 1.3 (which I used to do). However, I still
1526        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1527        workstation).
1528    
1529    24. Changed the PCRE licence to be the more standard "BSD" licence.
1530    
1531    
1532    Version 4.5 01-Dec-03
1533    ---------------------
1534    
1535     1. There has been some re-arrangement of the code for the match() function so
1536        that it can be compiled in a version that does not call itself recursively.
1537        Instead, it keeps those local variables that need separate instances for
1538        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1539        needs to "recurse". Keeping track of where control must go is done by means
1540        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1541        hide most of the details from the main code, and operates only if
1542        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1543        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1544        operating.
1545    
1546        To make it easier for callers to provide specially tailored get/free
1547        functions for this usage, two new functions, pcre_stack_malloc, and
1548        pcre_stack_free, are used. They are always called in strict stacking order,
1549        and the size of block requested is always the same.
1550    
1551        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1552        PCRE has been compiled to use the stack or the heap for recursion. The
1553        -C option of pcretest uses this to show which version is compiled.
1554    
1555        A new data escape \S, is added to pcretest; it causes the amounts of store
1556        obtained and freed by both kinds of malloc/free at match time to be added
1557        to the output.
1558    
1559     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1560        what's available on my current Linux desktop machine.
1561    
1562     3. When matching a UTF-8 string, the test for a valid string at the start has
1563        been extended. If start_offset is not zero, PCRE now checks that it points
1564        to a byte that is the start of a UTF-8 character. If not, it returns
1565        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1566        this is necessary because there may be backward assertions in the pattern.
1567        When matching the same subject several times, it may save resources to use
1568        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1569    
1570     4. The code for checking the validity of UTF-8 strings has been tightened so
1571        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1572        containing "overlong sequences".
1573    
1574     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1575        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1576        should have been "&", but it just so happened that all the cases this let
1577        through by mistake were picked up later in the function.
1578    
1579     6. I had used a variable called "isblank" - this is a C99 function, causing
1580        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1581    
1582     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1583        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1584        so the version is shown; (c) stop "make test" echoing "./RunTest".
1585    
1586     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1587    
1588     9. The prototype for memmove() for systems that don't have it was using
1589        size_t, but the inclusion of the header that defines size_t was later. I've
1590        moved the #includes for the C headers earlier to avoid this.
1591    
1592    10. Added some adjustments to the code to make it easier to compiler on certain
1593        special systems:
1594    
1595          (a) Some "const" qualifiers were missing.
1596          (b) Added the macro EXPORT before all exported functions; by default this
1597              is defined to be empty.
1598          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1599              that it reads its output file name as an argument instead of writing
1600              to the standard output and assuming this can be redirected.
1601    
1602    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1603        class containing characters with values greater than 255, PCRE compilation
1604        went into a loop.
1605    
1606    12. A recursive reference to a subpattern that was within another subpattern
1607        that had a minimum quantifier of zero caused PCRE to crash. For example,
1608        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1609        recursion. If the recursively-called subpattern itself had a zero repeat,
1610        that was OK.
1611    
1612    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1613        buffer into which it was copied (for escape processing) was still set at
1614        1024, so long lines caused crashes.
1615    
1616    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1617        "internal error: code overflow...". This applied to any character class
1618        that was followed by a possessive quantifier.
1619    
1620    15. Modified the Makefile to add libpcre.la as a prerequisite for
1621        libpcreposix.la because I was told this is needed for a parallel build to
1622        work.
1623    
1624    16. If a pattern that contained .* following optional items at the start was
1625        studied, the wrong optimizing data was generated, leading to matching
1626        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1627        matching string must start with a or b or c. The correct conclusion for
1628        this pattern is that a match can start with any character.
1629    
1630    
1631    Version 4.4 13-Aug-03
1632    ---------------------
1633    
1634     1. In UTF-8 mode, a character class containing characters with values between
1635        127 and 255 was not handled correctly if the compiled pattern was studied.
1636        In fixing this, I have also improved the studying algorithm for such
1637        classes (slightly).
1638    
1639     2. Three internal functions had redundant arguments passed to them. Removal
1640        might give a very teeny performance improvement.
1641    
1642     3. Documentation bug: the value of the capture_top field in a callout is *one
1643        more than* the number of the hightest numbered captured substring.
1644    
1645     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1646        in incorrectly linking with a previously installed version. They now link
1647        explicitly with libpcre.la.
1648    
1649     5. configure.in no longer needs to recognize Cygwin specially.
1650    
1651     6. A problem in pcre.in for Windows platforms is fixed.
1652    
1653     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1654        pcretest, it used to include the size of the study block as part of its
1655        output. Unfortunately, the structure contains a field that has a different
1656        size on different hardware architectures. This meant that the tests that
1657        showed this size failed. As the block is currently always of a fixed size,
1658        this information isn't actually particularly useful in pcretest output, so
1659        I have just removed it.
1660    
1661     8. Three pre-processor statements accidentally did not start in column 1.
1662        Sadly, there are *still* compilers around that complain, even though
1663        standard C has not required this for well over a decade. Sigh.
1664    
1665     9. In pcretest, the code for checking callouts passed small integers in the
1666        callout_data field, which is a void * field. However, some picky compilers
1667        complained about the casts involved for this on 64-bit systems. Now
1668        pcretest passes the address of the small integer instead, which should get
1669        rid of the warnings.
1670    
1671    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1672        both compile and run time, and gives an error if an invalid UTF-8 sequence
1673        is found. There is a option for disabling this check in cases where the
1674        string is known to be correct and/or the maximum performance is wanted.
1675    
1676    11. In response to a bug report, I changed one line in Makefile.in from
1677    
1678            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1679        to
1680            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1681    
1682        to look similar to other lines, but I have no way of telling whether this
1683        is the right thing to do, as I do not use Windows. No doubt I'll get told
1684        if it's wrong...
1685    
1686    
1687    Version 4.3 21-May-03
1688    ---------------------
1689    
1690    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1691       Makefile.
1692    
1693    2. Some refactoring to improve the quality of the code:
1694    
1695       (i)   The utf8_table... variables are now declared "const".
1696    
1697       (ii)  The code for \cx, which used the "case flipping" table to upper case
1698             lower case letters, now just substracts 32. This is ASCII-specific,
1699             but the whole concept of \cx is ASCII-specific, so it seems
1700             reasonable.
1701    
1702       (iii) PCRE was using its character types table to recognize decimal and
1703             hexadecimal digits in the pattern. This is silly, because it handles
1704             only 0-9, a-f, and A-F, but the character types table is locale-
1705             specific, which means strange things might happen. A private
1706             table is now used for this - though it costs 256 bytes, a table is
1707             much faster than multiple explicit tests. Of course, the standard
1708             character types table is still used for matching digits in subject
1709             strings against \d.
1710    
1711       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1712             ending in _t are). So I've renamed it as ESC_tee.
1713    
1714    3. The first argument for regexec() in the POSIX wrapper should have been
1715       defined as "const".
1716    
1717    4. Changed pcretest to use malloc() for its buffers so that they can be
1718       Electric Fenced for debugging.
1719    
1720    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1721       to read one or more bytes before the start of the subject string. Often this
1722       had no effect on PCRE's behaviour, but in some circumstances it could
1723       provoke a segmentation fault.
1724    
1725    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1726       to try to read one or more bytes before the start of the subject string.
1727    
1728    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1729       UTF-8 support could misbehave in various ways if the subject string
1730       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1731       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1732       back over UTF-8 characters.)
1733    
1734    
1735    Version 4.2 14-Apr-03
1736    ---------------------
1737    
1738    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1739    
1740    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1741         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1742         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1743         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1744         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1745           and BUILD_EXEEXT
1746         Note: automatic setting of the BUILD variables is not yet working
1747         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1748           compile-time but not at link-time
1749         [LINK]: use for linking executables only
1750         make different versions for Windows and non-Windows
1751         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1752           libraries
1753         [LINK_FOR_BUILD]: new variable
1754         [OBJEXT]: use throughout
1755         [EXEEXT]: use throughout
1756         <winshared>: new target
1757         <wininstall>: new target
1758         <dftables.o>: use native compiler
1759         <dftables>: use native linker
1760         <install>: handle Windows platform correctly
1761         <clean>: ditto
1762         <check>: ditto
1763         copy DLL to top builddir before testing
1764    
1765       As part of these changes, -no-undefined was removed again. This was reported
1766       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1767       in any case.
1768    
1769    3. Some tidies to get rid of compiler warnings:
1770    
1771       . In the match_data structure, match_limit was an unsigned long int, whereas
1772         match_call_count was an int. I've made them both unsigned long ints.
1773    
1774       . In pcretest the fact that a const uschar * doesn't automatically cast to
1775         a void * provoked a warning.
1776    
1777       . Turning on some more compiler warnings threw up some "shadow" variables
1778         and a few more missing casts.
1779    
1780    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1781       option, a class that contained a single character with a value between 128
1782       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1783    
1784    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1785       option, a class that contained several characters, but with at least one
1786       whose value was between 128 and 255 caused PCRE to crash.
1787    
1788    
1789    Version 4.1 12-Mar-03
1790    ---------------------
1791    
1792    1. Compiling with gcc -pedantic found a couple of places where casts were
1793    needed, and a string in dftables.c that was longer than standard compilers are
1794    required to support.
1795    
1796    2. Compiling with Sun's compiler found a few more places where the code could
1797    be tidied up in order to avoid warnings.
1798    
1799    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1800    first of these names is deprecated in the latest Autoconf in favour of the name
1801    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1802    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1803    analogy I have changed it to CFLAGS_FOR_BUILD.
1804    
1805    4. Added -no-undefined to the linking command in the Makefile, because this is
1806    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1807    linking step for the pcreposix library.
1808    
1809    5. PCRE was failing to diagnose the case of two named groups with the same
1810    name.
1811    
1812    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1813    literal character that is needed in the subject for a match, and scans along to
1814    ensure that it is present before embarking on the full matching process. This
1815    saves time in cases of nested unlimited repeats that are never going to match.
1816    Problem: the scan can take a lot of time if the subject is very long (e.g.
1817    megabytes), thus penalizing straightforward matches. It is now done only if the
1818    amount of subject to be scanned is less than 1000 bytes.
1819    
1820    7. A lesser problem with the same optimization is that it was recording the
1821    first character of an anchored pattern as "needed", thus provoking a search
1822    right along the subject, even when the first match of the pattern was going to
1823    fail. The "needed" character is now not set for anchored patterns, unless it
1824    follows something in the pattern that is of non-fixed length. Thus, it still
1825    fulfils its original purpose of finding quick non-matches in cases of nested
1826    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1827    
1828    
1829    Version 4.0 17-Feb-03
1830    ---------------------
1831    
1832    1. If a comment in an extended regex that started immediately after a meta-item
1833    extended to the end of string, PCRE compiled incorrect data. This could lead to
1834    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1835    
1836    2. Moved to autoconf 2.53 and libtool 1.4.2.
1837    
1838    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1839    the special perltest8 script is no longer needed - all the tests can be run
1840    from a single perltest script.
1841    
1842    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1843    by \s. It has now been removed in PCRE. This means it isn't recognized as
1844    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1845    class [:space:] *does* include VT, thereby creating a mess.
1846    
1847    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1848    space and tab.
1849    
1850    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1851    its new features into the main test script, reducing the number of scripts.
1852    
1853    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1854    were backward compatible, and made the (?i) apply to the whole pattern, as if
1855    /i were given. Now it behaves more logically, and applies the option setting
1856    only to what follows. PCRE has been changed to follow suit. However, if it
1857    finds options settings right at the start of the pattern, it extracts them into
1858    the global options, as before. Thus, they show up in the info data.
1859    
1860    8. Added support for the \Q...\E escape sequence. Characters in between are
1861    treated as literals. This is slightly different from Perl in that $ and @ are
1862    also handled as literals inside the quotes. In Perl, they will cause variable
1863    interpolation. Note the following examples:
1864    
1865        Pattern            PCRE matches      Perl matches
1866    
1867        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1868        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1869        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1870    
1871    For compatibility with Perl, \Q...\E sequences are recognized inside character
1872    classes as well as outside them.
1873    
1874    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1875    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1876    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1877    signed/unsigned warnings.
1878    
1879    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1880    option for pcretest, so I've replaced it by a simple function that does just
1881    that job.
1882    
1883    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1884    "pcregrep -".
1885    
1886    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1887    Java package. This provides some syntactic sugar for simple cases of what my
1888    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1889    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1890    item, you can use this simplified notation. Note that only makes sense with
1891    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1892    greediness, whatever the setting of the PCRE_UNGREEDY option.
1893    
1894    13. A change of greediness default within a pattern was not taking effect at
1895    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1896    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1897    was abstracted outside.
1898    
1899    14. PCRE now supports the \G assertion. It is true when the current matching
1900    position is at the start point of the match. This differs from \A when the
1901    starting offset is non-zero. Used with the /g option of pcretest (or similar
1902    code), it works in the same way as it does for Perl's /g option. If all
1903    alternatives of a regex begin with \G, the expression is anchored to the start
1904    match position, and the "anchored" flag is set in the compiled expression.
1905    
1906    15. Some bugs concerning the handling of certain option changes within patterns
1907    have been fixed. These applied to options other than (?ims). For example,
1908    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1909    been the other way round. Some of this was related to change 7 above.
1910    
1911    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1912    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1913    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1914    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1915    
1916    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1917    mode. Unlike ".", it always matches newline, whatever the setting of
1918    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1919    assertions. Perl allows it, but it doesn't (in general) work because it can't
1920    calculate the length of the lookbehind. At least, that's the case for Perl
1921    5.8.0 - I've been told they are going to document that it doesn't work in
1922    future.
1923    
1924    18. Added an error diagnosis for escapes that PCRE does not support: these are
1925    \L, \l, \N, \P, \p, \U, \u, and \X.
1926    
1927    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1928    reading past the end of the pattern in cases such as /[abcd/.
1929    
1930    20. PCRE was getting more memory than necessary for patterns with classes that
1931    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1932    
1933    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1934    compiling PCRE for use with Virtual Pascal.
1935    
1936    22. Small fix to the Makefile to make it work properly if the build is done
1937    outside the source tree.
1938    
1939    23. Added a new extension: a condition to go with recursion. If a conditional
1940    subpattern starts with (?(R) the "true" branch is used if recursion has
1941    happened, whereas the "false" branch is used only at the top level.
1942    
1943    24. When there was a very long string of literal characters (over 255 bytes
1944    without UTF support, over 250 bytes with UTF support), the computation of how
1945    much memory was required could be incorrect, leading to segfaults or other
1946    strange effects.
1947    
1948    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1949    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1950    there was a subsequent back reference to those brackets. This meant that, for
1951    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1952    possible to check for precisely this case. All we can do is abandon the
1953    optimization if .* occurs inside capturing brackets when there are any back
1954    references whatsoever. (See below for a better fix that came later.)
1955    
1956    26. The handling of the optimization for finding the first character of a
1957    non-anchored pattern, and for finding a character that is required later in the
1958    match were failing in some cases. This didn't break the matching; it just
1959    failed to optimize when it could. The way this is done has been re-implemented.
1960    
1961    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1962    
1963    28. Added a new feature that provides some of the functionality that Perl
1964    provides with (?{...}). The facility is termed a "callout". The way it is done
1965    in PCRE is for the caller to provide an optional function, by setting
1966    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1967    global variable. By default it is unset, which disables all calling out. To get
1968    the function called, the regex must include (?C) at appropriate points. This
1969    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1970    This provides a means of identifying different callout points. When PCRE
1971    reaches such a point in the regex, if pcre_callout has been set, the external
1972    function is called. It is provided with data in a structure called
1973    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1974    matching continues; if it returns a non-zero value, the match at the current
1975    point fails. However, backtracking will occur if possible. [This was changed
1976    later and other features added - see item 49 below.]
1977    
1978    29. pcretest is upgraded to test the callout functionality. It provides a
1979    callout function that displays information. By default, it shows the start of
1980    the match and the current position in the text. There are some new data escapes
1981    to vary what happens:
1982    
1983        \C+         in addition, show current contents of captured substrings
1984        \C-         do not supply a callout function
1985        \C!n        return 1 when callout number n is reached
1986        \C!n!m      return 1 when callout number n is reached for the mth time
1987    
1988    30. If pcregrep was called with the -l option and just a single file name, it
1989    output "<stdin>" if a match was found, instead of the file name.
1990    
1991    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1992    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1993    pcre_exec(). This saves a malloc/free per call. The default value of
1994    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1995    when configuring.
1996    
1997    32. The default maximum size of a compiled pattern is 64K. There have been a
1998    few cases of people hitting this limit. The code now uses macros to handle the
1999    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2000    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2001    configuring. Tests 2 and 5 work only with 2-byte links because they output
2002    debugging information about compiled patterns.
2003    
2004    33. Internal code re-arrangements:
2005    
2006    (a) Moved the debugging function for printing out a compiled regex into
2007        its own source file (printint.c) and used #include to pull it into
2008        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2009        separate copies.
2010    
2011    (b) Defined the list of op-code names for debugging as a macro in
2012        internal.h so that it is next to the definition of the opcodes.
2013    
2014    (c) Defined a table of op-code lengths for simpler skipping along compiled
2015        code. This is again a macro in internal.h so that it is next to the
2016        definition of the opcodes.
2017    
2018    34. Added support for recursive calls to individual subpatterns, along the
2019    lines of Robin Houston's patch (but implemented somewhat differently).
2020    
2021    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2022    allow it to read and process whole directories in Win32. This code was
2023    contributed by Lionel Fourquaux; it has not been tested by me.
2024    
2025    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2026    used to name a group. Names consist of alphanumerics and underscores, and must
2027    be unique. Back references use the syntax (?P=name) and recursive calls use
2028    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2029    numbers. The function pcre_fullinfo() can be used after compilation to extract
2030    a name/number map. There are three relevant calls:
2031    
2032      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2033      PCRE_INFO_NAMECOUNT            yields the number of entries
2034      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2035    
2036    The map is a vector of fixed-size entries. The size of each entry depends on
2037    the length of the longest name used. The first two bytes of each entry are the
2038    group number, most significant byte first. There follows the corresponding
2039    name, zero terminated. The names are in alphabetical order.
2040    
2041    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2042    case instead of 255. Making it the same both with and without UTF-8 support
2043    means that the same test output works with both.
2044    
2045    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2046    calling malloc() with a zero argument.
2047    
2048    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2049    optimization. I've improved things by keeping a bitmap of backreferences with
2050    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2051    fact referenced, the optimization can be applied. It is unlikely that a
2052    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2053    the match to follow \n) will appear inside brackets with a number greater than
2054    31, but if it does, any back reference > 31 suppresses the optimization.
2055    
2056    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2057    of disabling numbered capturing parentheses. Any opening parenthesis that is
2058    not followed by ? behaves as if it were followed by ?: but named parentheses
2059    can still be used for capturing (and they will acquire numbers in the usual
2060    way).
2061    
2062    41. Redesigned the return codes from the match() function into yes/no/error so
2063    that errors can be passed back from deep inside the nested calls. A malloc
2064    failure while inside a recursive subpattern call now causes the
2065    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2066    
2067    42. It is now possible to set a limit on the number of times the match()
2068    function is called in a call to pcre_exec(). This facility makes it possible to
2069    limit the amount of recursion and backtracking, though not in a directly
2070    obvious way, because the match() function is used in a number of different
2071    circumstances. The count starts from zero for each position in the subject
2072    string (for non-anchored patterns). The default limit is, for compatibility, a
2073    large number, namely 10 000 000. You can change this in two ways:
2074    
2075    (a) When configuring PCRE before making, you can use --with-match-limit=n
2076        to set a default value for the compiled library.
2077    
2078    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2079        a different value is set. See 45 below.
2080    
2081    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2082    
2083    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2084    of things that can be changed at compile time. The first argument specifies
2085    what is wanted and the second points to where the information is to be placed.
2086    The current list of available information is:
2087    
2088      PCRE_CONFIG_UTF8
2089    
2090    The output is an integer that is set to one if UTF-8 support is available;
2091    otherwise it is set to zero.
2092    
2093      PCRE_CONFIG_NEWLINE
2094    
2095    The output is an integer that it set to the value of the code that is used for
2096    newline. It is either LF (10) or CR (13).
2097    
2098      PCRE_CONFIG_LINK_SIZE
2099    
2100    The output is an integer that contains the number of bytes used for internal
2101    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2102    
2103      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2104    
2105    The output is an integer that contains the threshold above which the POSIX
2106    interface uses malloc() for output vectors. See item 31 above.
2107    
2108      PCRE_CONFIG_MATCH_LIMIT
2109    
2110    The output is an unsigned integer that contains the default limit of the number
2111    of match() calls in a pcre_exec() execution. See 42 above.
2112    
2113    44. pcretest has been upgraded by the addition of the -C option. This causes it
2114    to extract all the available output from the new pcre_config() function, and to
2115    output it. The program then exits immediately.
2116    
2117    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2118    order to support additional features. One way would have been to define
2119    pcre_exec2() (for example) with extra arguments, but this would not have been
2120    extensible, and would also have required all calls to the original function to
2121    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2122    is used for passing in "extra" data from pcre_study().
2123    
2124    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2125    contains the following fields:
2126    
2127      flags         a bitmap indicating which of the following fields are set
2128      study_data    opaque data from pcre_study()
2129      match_limit   a way of specifying a limit on match() calls for a specific
2130                      call to pcre_exec()
2131      callout_data  data for callouts (see 49 below)
2132    
2133    The flag bits are also defined in pcre.h, and are
2134    
2135      PCRE_EXTRA_STUDY_DATA
2136      PCRE_EXTRA_MATCH_LIMIT
2137      PCRE_EXTRA_CALLOUT_DATA
2138    
2139    The pcre_study() function now returns one of these new pcre_extra blocks, with
2140    the actual study data pointed to by the study_data field, and the
2141    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2142    before. That is, this change is entirely upwards-compatible and requires no
2143    change to existing code.
2144    
2145    If you want to pass in additional data to pcre_exec(), you can either place it
2146    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2147    block.
2148    
2149    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2150    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2151    times with different match limits, until it finds the minimum value needed for
2152    pcre_exec() to complete. The value is then output. This can be instructive; for
2153    most simple matches the number is quite small, but for pathological cases it
2154    gets very large very quickly.
2155    
2156    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2157    returns the size of the data block pointed to by the study_data field in a
2158    pcre_extra block, that is, the value that was passed as the argument to
2159    pcre_malloc() when PCRE was getting memory in which to place the information
2160    created by pcre_study(). The fourth argument should point to a size_t variable.
2161    pcretest has been extended so that this information is shown after a successful
2162    pcre_study() call when information about the compiled regex is being displayed.
2163    
2164    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2165    because what follows is always an absolute path. (Later: it turns out that this
2166    is more than cosmetic for MinGW, because it doesn't like empty path
2167    components.)
2168    
2169    49. Some changes have been made to the callout feature (see 28 above):
2170    
2171    (i)  A callout function now has three choices for what it returns:
2172    
2173           0  =>  success, carry on matching
2174         > 0  =>  failure at this point, but backtrack if possible
2175         < 0  =>  serious error, return this value from pcre_exec()
2176    
2177         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2178         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2179         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2180         use by callout functions. It will never be used by PCRE itself.
2181    
2182    (ii) The pcre_extra structure (see 45 above) has a void * field called
2183         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2184         pcre_callout_block structure has a field of the same name. The contents of
2185         the field passed in the pcre_extra structure are passed to the callout
2186         function in the corresponding field in the callout block. This makes it
2187         easier to use the same callout-containing regex from multiple threads. For
2188         testing, the pcretest program has a new data escape
2189    
2190           \C*n        pass the number n (may be negative) as callout_data
2191    
2192         If the callout function in pcretest receives a non-zero value as
2193         callout_data, it returns that value.
2194    
2195    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2196    there were some redundant $(CFLAGS) in commands that are now specified as
2197    $(LINK), which already includes $(CFLAGS).
2198    
2199    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2200    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2201    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2202    one-byte characters throughout. Note that case-insensitive matching applies
2203    only to characters whose values are less than 256. PCRE doesn't support the
2204    notion of cases for higher-valued characters.
2205    
2206    (i)   A character class whose characters are all within 0-255 is handled as
2207          a bit map, and the map is inverted for negative classes. Previously, a
2208          character > 255 always failed to match such a class; however it should
2209          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2210    
2211    (ii)  A negated character class with a single character < 255 is coded as
2212          "not this character" (OP_NOT). This wasn't working properly when the test
2213          character was multibyte, either singly or repeated.
2214    
2215    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2216          mode, for example: \x{100}{2,3}.
2217    
2218    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2219          singly or repeated) now correctly test multibyte characters. However,
2220          PCRE doesn't recognize any characters with values greater than 255 as
2221          digits, spaces, or word characters. Such characters always match \D, \S,
2222          and \W, and never match \d, \s, or \w.
2223    
2224    (v)   Classes may now contain characters and character ranges with values
2225          greater than 255. For example: [ab\x{100}-\x{400}].
2226    
2227    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2228          PCRE in UTF-8 mode.
2229    
2230    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2231    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2232    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2233    value.)
2234    
2235    53. The single man page has become too large. I have therefore split it up into
2236    a number of separate man pages. These also give rise to individual HTML pages;
2237    these are now put in a separate directory, and there is an index.html page that
2238    lists them all. Some hyperlinking between the pages has been installed.
2239    
2240    54. Added convenience functions for handling named capturing parentheses.
2241    
2242    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2243    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2244    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2245    are faulted.
2246    
2247    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2248    calling configure. These values are used when compiling the dftables.c program
2249    which is run to generate the source of the default character tables. They
2250    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2251    you will need to set these values.
2252    
2253    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2254    
2255    
2256    Version 3.9 02-Jan-02
2257    ---------------------
2258    
2259    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2260    
2261    2. If --disable-static was given, the building process failed when trying to
2262    build pcretest and pcregrep. (For some reason it was using libtool to compile
2263    them, which is not right, as they aren't part of the library.)
2264    
2265    
2266    Version 3.8 18-Dec-01
2267    ---------------------
2268    
2269    1. The experimental UTF-8 code was completely screwed up. It was packing the
2270    bytes in the wrong order. How dumb can you get?
2271    
2272    
2273    Version 3.7 29-Oct-01
2274    ---------------------
2275    
2276    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2277    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2278    this didn't happen under Solaris 8, where I normally test things.
2279    
2280    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2281    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2282    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2283    this fix an hour or so after the initial 3.7 release.)
2284    
2285    
2286    Version 3.6 23-Oct-01
2287    ---------------------
2288    
2289    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2290    offsets passed as NULL with zero offset count.
2291    
2292    2. The config.guess and config.sub files had not been updated when I moved to
2293    the latest autoconf.
2294    
2295    
2296    Version 3.5 15-Aug-01
2297    ---------------------
2298    
2299    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2300    had been forgotten.
2301    
2302    2. By using declared but undefined structures, we can avoid using "void"
2303    definitions in pcre.h while keeping the internal definitions of the structures
2304    private.
2305    
2306    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2307    user point of view, this means that both static and shared libraries are built
2308    by default, but this can be individually controlled. More of the work of
2309    handling this static/shared cases is now inside libtool instead of PCRE's make
2310    file.
2311    
2312    4. The pcretest utility is now installed along with pcregrep because it is
2313    useful for users (to test regexs) and by doing this, it automatically gets
2314    relinked by libtool. The documentation has been turned into a man page, so
2315    there are now .1, .txt, and .html versions in /doc.
2316    
2317    5. Upgrades to pcregrep:
2318       (i)   Added long-form option names like gnu grep.
2319       (ii)  Added --help to list all options with an explanatory phrase.
2320       (iii) Added -r, --recursive to recurse into sub-directories.
2321       (iv)  Added -f, --file to read patterns from a file.
2322    
2323    6. pcre_exec() was referring to its "code" argument before testing that
2324    argument for NULL (and giving an error if it was NULL).
2325    
2326    7. Upgraded Makefile.in to allow for compiling in a different directory from
2327    the source directory.
2328    
2329    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2330    options bits, the pointer it was passed was to an int instead of to an unsigned
2331    long int. This mattered only on 64-bit systems.
2332    
2333    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2334    generated) instead of pcre.in, which it its source. Also made the same change
2335    in several of the .c files.
2336    
2337    10. A new release of gcc defines printf() as a macro, which broke pcretest
2338    because it had an ifdef in the middle of a string argument for printf(). Fixed
2339    by using separate calls to printf().
2340    
2341    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2342    script, to force use of CR or LF instead of \n in the source. On non-Unix
2343    systems, the value can be set in config.h.
2344    
2345    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2346    absolute limit. Changed the text of the error message to make this clear, and
2347    likewise updated the man page.
2348    
2349    13. The limit of 99 on the number of capturing subpatterns has been removed.
2350    The new limit is 65535, which I hope will not be a "real" limit.
2351    
2352    
2353    Version 3.4 22-Aug-00
2354    ---------------------
2355    
2356    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2357    
2358    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2359    
2360    
2361    Version 3.3 01-Aug-00
2362    ---------------------
2363    
2364    1. If an octal character was given, but the value was greater than \377, it
2365    was not getting masked to the least significant bits, as documented. This could
2366    lead to crashes in some systems.
2367    
2368    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2369    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2370    
2371    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2372    These just pass their arguments on to (pcre_free)(), but they are provided
2373    because some uses of PCRE bind it to non-C systems that can call its functions,
2374    but cannot call free() or pcre_free() directly.
2375    
2376    4. Add "make test" as a synonym for "make check". Corrected some comments in
2377    the Makefile.
2378    
2379    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2380    Makefile.
2381    
2382    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2383    command called pgrep for grepping around the active processes.
2384    
2385    7. Added the beginnings of support for UTF-8 character strings.
2386    
2387    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2388    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2389    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2390    out for the ar command.)
2391    
2392    
2393    Version 3.2 12-May-00
2394    ---------------------
2395    
2396    This is purely a bug fixing release.
2397    
2398    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2399    of ZA. This was just one example of several cases that could provoke this bug,
2400    which was introduced by change 9 of version 2.00. The code for breaking
2401    infinite loops after an iteration that matches an empty string was't working
2402    correctly.
2403    
2404    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2405    when matched against abbab (for example). After matching an empty string, it
2406    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2407    caused it to match further down the string than it should.
2408    
2409    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2410    was there because it doesn't seem to be needed, and it causes trouble on some
2411    systems, as it is not a Standard C header. It has been removed.
2412    
2413    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2414    were reported on the Macintosh. The changes were from
2415    
2416      while ((c = *(++ptr)) != 0 && c != '\n');
2417    to
2418      while ((c = *(++ptr)) != 0 && c != '\n') ;
2419    
2420    Totally extraordinary, but if that's what it takes...
2421    
2422    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2423    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2424    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2425    assumes the way PCRE uses memmove() (always moving upwards).
2426    
2427    6. PCRE is being used in one environment where strchr() is not available. There
2428    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2429    faster code anyway.
2430    
2431    
2432    Version 3.1 09-Feb-00
2433    ---------------------
2434    
2435    The only change in this release is the fixing of some bugs in Makefile.in for
2436    the "install" target:
2437    
2438    (1) It was failing to install pcreposix.h.
2439    
2440    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2441    
2442    
2443    Version 3.0 01-Feb-00
2444    ---------------------
2445    
2446    1. Add support for the /+ modifier to perltest (to output $` like it does in
2447    pcretest).
2448    
2449    2. Add support for the /g modifier to perltest.
2450    
2451    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2452    matches null strings.
2453    
2454    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2455    pattern. Perl treats empty patterns specially - it reuses the most recent
2456    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2457    effect.
2458    
2459    5. The POSIX interface was broken in that it was just handing over the POSIX
2460    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2461    required a bigger vector, with some working space on the end. This means that
2462    the POSIX wrapper now has to get and free some memory, and copy the results.
2463    
2464    6. Added some simple autoconf support, placing the test data and the
2465    documentation in separate directories, re-organizing some of the
2466    information files, and making it build pcre-config (a GNU standard). Also added
2467    libtool support for building PCRE as a shared library, which is now the
2468    default.
2469    
2470    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2471    09 are not valid octal constants. Single digits will be used for minor values
2472    less than 10.
2473    
2474    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2475    existing programs that set these in the POSIX interface can use PCRE without
2476    modification.
2477    
2478    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2479    return all that pcre_info() returns, plus additional data. The pcre_info()
2480    function is retained for compatibility, but is considered to be obsolete.
2481    
2482    10. Added experimental recursion feature (?R) to handle one common case that
2483    Perl 5.6 will be able to do with (?p{...}).
2484    
2485    11. Added support for POSIX character classes like [:alpha:], which Perl is
2486    adopting.
2487    
2488    
2489    Version 2.08 31-Aug-99
2490    ----------------------
2491    
2492    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2493    trying to match at the startoffset position, but instead was moving forward to
2494    the next newline as if a previous match had failed.
2495    
2496    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2497    and could get into a loop if a null string was matched other than at the start
2498    of the subject.
2499    
2500    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2501    be distinguished at compile time, and for completeness also added PCRE_DATE.
2502    
2503    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2504    in GnuWin32 environments.
2505    
2506    
2507    Version 2.07 29-Jul-99
2508    ----------------------
2509    
2510    1. The documentation is now supplied in plain text form and HTML as well as in
2511    the form of man page sources.
2512    
2513    2. C++ compilers don't like assigning (void *) values to other pointer types.
2514    In particular this affects malloc(). Although there is no problem in Standard
2515    C, I've put in casts to keep C++ compilers happy.
2516    
2517    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2518    should be (const char *).
2519    
2520    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2521    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2522    However, I haven't made this a standard facility. The documentation doesn't
2523    mention it, and the Makefile doesn't support it.
2524    
2525    5. The Makefile now contains an "install" target, with editable destinations at
2526    the top of the file. The pcretest program is not installed.
2527    
2528    6. pgrep -V now gives the PCRE version number and date.
2529    
2530    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2531    causing the entire string to be ignored, instead of just the last character.
2532    
2533    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2534    non-matching string, it can take a very, very long time, even for strings of
2535    quite modest length, because of the nested recursion. PCRE now does better in
2536    some of these cases. It does this by remembering the last required literal
2537    character in the pattern, and pre-searching the subject to ensure it is present
2538    before running the real match. In other words, it applies a heuristic to detect
2539    some types of certain failure quickly, and in the above example, if presented
2540    with a string that has no trailing " it gives "no match" very quickly.
2541    
2542    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2543    other alternatives are tried instead.
2544    
2545    
2546    Version 2.06 09-Jun-99
2547    ----------------------
2548    
2549    1. Change pcretest's output for amount of store used to show just the code
2550    space, because the remainder (the data block) varies in size between 32-bit and
2551    64-bit systems.
2552    
2553    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2554    start matching at. This allows lookbehinds to work when searching for multiple
2555    occurrences in a string.
2556    
2557    3. Added additional options to pcretest for testing multiple occurrences:
2558    
2559       /+   outputs the rest of the string that follows a match
2560       /g   loops for multiple occurrences, using the new startoffset argument
2561       /G   loops for multiple occurrences by passing an incremented pointer
2562    
2563    4. PCRE wasn't doing the "first character" optimization for patterns starting
2564    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2565    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2566    the letter 'x'. On long subject strings, this gives a significant speed-up.
2567    
2568    
2569    Version 2.05 21-Apr-99
2570    ----------------------
2571    
2572    1. Changed the type of magic_number from int to long int so that it works
2573    properly on 16-bit systems.
2574    
2575    2. Fixed a bug which caused patterns starting with .* not to work correctly
2576    when the subject string contained newline characters. PCRE was assuming
2577    anchoring for such patterns in all cases, which is not correct because .* will
2578    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2579    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2580    must be retried after every newline in the subject.
2581    
2582    
2583    Version 2.04 18-Feb-99
2584    ----------------------
2585    
2586    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2587    computation of the store needed to hold the pattern was incorrect (too large).
2588    If such patterns were nested a few deep, this could multiply and become a real
2589    problem.
2590    
2591    2. Added /M option to pcretest to show the memory requirement of a specific
2592    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2593    
2594    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2595    compiled in such a way that the backtracking after subsequent failure was
2596    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2597    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2598    
2599    
2600    Version 2.03 02-Feb-99
2601    ----------------------
2602    
2603    1. Fixed typo and small mistake in man page.
2604    
2605    2. Added 4th condition (GPL supersedes if conflict) and created separate
2606    LICENCE file containing the conditions.
2607    
2608    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2609    Perl, that is the internal \ allows the delimiter to be included in the
2610    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2611    the final delimiter, add \ to the end of the pattern (to test the error).
2612    
2613    4. Added the convenience functions for extracting substrings after a successful
2614    match. Updated pcretest to make it able to test these functions.
2615    
2616    
2617    Version 2.02 14-Jan-99
2618    ----------------------
2619    
2620    1. Initialized the working variables associated with each extraction so that
2621    their saving and restoring doesn't refer to uninitialized store.
2622    
2623    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2624    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2625    fix the problem.
2626    
2627    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2628    calls, and wasn't printing the correct value for compiling calls. Increased the
2629    default value of LOOPREPEAT, and the number of significant figures in the
2630    times.
2631    
2632    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2633    
2634    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2635    a building problem on Windows NT with a FAT file system.
2636    
2637    
2638    Version 2.01 21-Oct-98
2639    ----------------------
2640    
2641    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2642    to character tables built by pcre_maketables() in the current locale. If NULL
2643    is passed, the default tables are used.
2644    
2645    
2646    Version 2.00 24-Sep-98
2647    ----------------------
2648    
2649    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2650    it any more.
2651    
2652    2. Allow quantification of (?>) groups, and make it work correctly.
2653    
2654    3. The first character computation wasn't working for (?>) groups.
2655    
2656    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2657    end of the subject) and add 5.005's \z, which really does match only at the
2658    very end of the subject.
2659    
2660    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2661    
2662    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2663    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2664    localized options. All options to pcre_study() were also removed.
2665    
2666    7. Add other new features from 5.005:
2667    
2668       $(?<=           positive lookbehind
2669       $(?<!           negative lookbehind
2670       (?imsx-imsx)    added the unsetting capability
2671                       such a setting is global if at outer level; local otherwise
2672       (?imsx-imsx:)   non-capturing groups with option setting
2673       (?(cond)re|re)  conditional pattern matching
2674    
2675       A backreference to itself in a repeated group matches the previous
2676       captured string.
2677    
2678    8. General tidying up of studying (both automatic and via "study")
2679    consequential on the addition of new assertions.
2680    
2681    9. As in 5.005, unlimited repeated groups that could match an empty substring
2682    are no longer faulted at compile time. Instead, the loop is forcibly broken at
2683    runtime if any iteration does actually match an empty substring.
2684    
2685    10. Include the RunTest script in the distribution.
2686    
2687    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2688    discrepancies, some of which were old and were also with respect to 5.004. They
2689    have now been fixed.
2690    
2691    
2692    Version 1.09 28-Apr-98
2693    ----------------------
2694    
2695    1. A negated single character class followed by a quantifier with a minimum
2696    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
2697    program crashes, or just wrong answers. This did not apply to negated classes
2698    containing more than one character, or to minima other than one.
2699    
2700    
2701    Version 1.08 27-Mar-98
2702    ----------------------
2703    
2704    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2705    
2706    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2707    latter must appear before anything that relies on it in the pattern.
2708    
2709    
2710    Version 1.07 16-Feb-98
2711    ----------------------
2712    
2713    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2714    repeat of a potentially empty string).
2715    
2716    
2717    Version 1.06 23-Jan-98
2718    ----------------------
2719    
2720    1. Added Markus Oberhumer's little patches for C++.
2721    
2722    2. Literal strings longer than 255 characters were broken.
2723    
2724    
2725    Version 1.05 23-Dec-97
2726    ----------------------
2727    
2728    1. Negated character classes containing more than one character were failing if
2729    PCRE_CASELESS was set at run time.
2730    
2731    
2732    Version 1.04 19-Dec-97
2733    ----------------------
2734    
2735    1. Corrected the man page, where some "const" qualifiers had been omitted.
2736    
2737    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2738    input syntax.
2739    
2740    3. Fixed memory leak which occurred when a regex with back references was
2741    matched with an offsets vector that wasn't big enough. The temporary memory
2742    that is used in this case wasn't being freed if the match failed.
2743    
2744    4. Tidied pcretest to ensure it frees memory that it gets.
2745    
2746    5. Temporary memory was being obtained in the case where the passed offsets
2747    vector was exactly big enough.
2748    
2749    6. Corrected definition of offsetof() from change 5 below.
2750    
2751    7. I had screwed up change 6 below and broken the rules for the use of
2752    setjmp(). Now fixed.
2753    
2754    
2755    Version 1.03 18-Dec-97
2756    ----------------------
2757    
2758    1. A erroneous regex with a missing opening parenthesis was correctly
2759    diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2760    on some systems.
2761    
2762    2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2763    it was reported that one broken compiler failed on the former because "code" is
2764    also an independent variable.
2765    
2766    3. The erroneous regex a[]b caused an array overrun reference.
2767    
2768    4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2769    fail on data ending with that character. (It was going on too far, and checking
2770    the next character, typically a binary zero.) This was specific to the
2771    optimized code for single-character negative classes.
2772    
2773    5. Added a contributed patch from the TIN world which does the following:
2774    
2775      + Add an undef for memmove, in case the the system defines a macro for it.
2776    
2777      + Add a definition of offsetof(), in case there isn't one. (I don't know
2778        the reason behind this - offsetof() is part of the ANSI standard - but
2779        it does no harm).
2780    
2781      + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2782        most of the places where whitespace preceded '#'. I have given up and
2783        allowed the remaining 2 cases to be at the margin.
2784    
2785      + Rename some variables in pcre to eliminate shadowing. This seems very
2786        pedantic, but does no harm, of course.
2787    
2788    6. Moved the call to setjmp() into its own function, to get rid of warnings
2789    from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2790    
2791    7. Constructs such as \d{8,} were compiling into the equivalent of
2792    \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2793    outcome, but in this particular case used more store than had been allocated,
2794    which caused the bug to be discovered because it threw up an internal error.
2795    
2796    8. The debugging code in both pcre and pcretest for outputting the compiled
2797    form of a regex was going wrong in the case of back references followed by
2798    curly-bracketed repeats.
2799    
2800    
2801  Version 1.02 12-Dec-97  Version 1.02 12-Dec-97
2802  ----------------------  ----------------------

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