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

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