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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 (where
36        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    
42    Version 7.3 28-Aug-07
43    ---------------------
44    
45     1. In the rejigging of the build system that eventually resulted in 7.1, the
46        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
47        brackets there is not right, since it causes compilers to look for an
48        installed pcre.h, not the version that is in the source that is being
49        compiled (which of course may be different). I have changed it back to:
50    
51          #include "pcre.h"
52    
53        I have a vague recollection that the change was concerned with compiling in
54        different directories, but in the new build system, that is taken care of
55        by the VPATH setting the Makefile.
56    
57     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
58        when the subject happened to end in the byte 0x85 (e.g. if the last
59        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
60        characters but of course it shouldn't be taken as a newline when it is part
61        of another character. The bug was that, for an unlimited repeat of . in
62        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
63        characters when looking for a newline.
64    
65     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
66    
67     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
68        in debug output.
69    
70     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
71        long printing in the pcrecpp unittest when running under MinGW.
72    
73     6. ESC_K was left out of the EBCDIC table.
74    
75     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
76        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
77        limit also applies to "virtual nesting" when a pattern is recursive, and in
78        this case 1000 isn't so big. I have been able to remove this limit at the
79        expense of backing off one optimization in certain circumstances. Normally,
80        when pcre_exec() would call its internal match() function recursively and
81        immediately return the result unconditionally, it uses a "tail recursion"
82        feature to save stack. However, when a subpattern that can match an empty
83        string has an unlimited repetition quantifier, it no longer makes this
84        optimization. That gives it a stack frame in which to save the data for
85        checking that an empty string has been matched. Previously this was taken
86        from the 1000-entry workspace that had been reserved. So now there is no
87        explicit limit, but more stack is used.
88    
89     8. Applied Daniel's patches to solve problems with the import/export magic
90        syntax that is required for Windows, and which was going wrong for the
91        pcreposix and pcrecpp parts of the library. These were overlooked when this
92        problem was solved for the main library.
93    
94     9. There were some crude static tests to avoid integer overflow when computing
95        the size of patterns that contain repeated groups with explicit upper
96        limits. As the maximum quantifier is 65535, the maximum group length was
97        set at 30,000 so that the product of these two numbers did not overflow a
98        32-bit integer. However, it turns out that people want to use groups that
99        are longer than 30,000 bytes (though not repeat them that many times).
100        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
101        made it possible to implement the integer overflow checks in a much more
102        dynamic way, which I have now done. The artificial limitation on group
103        length has been removed - we now have only the limit on the total length of
104        the compiled pattern, which depends on the LINK_SIZE setting.
105    
106    10. Fixed a bug in the documentation for get/copy named substring when
107        duplicate names are permitted. If none of the named substrings are set, the
108        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
109        empty string.
110    
111    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
112        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
113        because the ] is interpreted as the first data character and the
114        terminating ] is not found. PCRE has been made compatible with Perl in this
115        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
116        cause memory overwriting.
117    
118    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
119        string has been matched (to stop an infinite loop). It was not recognizing
120        a conditional subpattern that could match an empty string if that
121        subpattern was within another subpattern. For example, it looped when
122        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
123        condition was not nested. This bug has been fixed.
124    
125    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
126        past the start of the subject in the presence of bytes with the top bit
127        set, for example "\x8aBCD".
128    
129    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
130        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
131    
132    14. Optimized (?!) to (*FAIL).
133    
134    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
135        This restricts code points to be within the range 0 to 0x10FFFF, excluding
136        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
137        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
138        does: it's just the validity check that is more restrictive.
139    
140    16. Inserted checks for integer overflows during escape sequence (backslash)
141        processing, and also fixed erroneous offset values for syntax errors during
142        backslash processing.
143    
144    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
145        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
146    
147    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
148        caused an overrun.
149    
150    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
151        something other than just ASCII characters) inside a group that had an
152        unlimited repeat caused a loop at compile time (while checking to see
153        whether the group could match an empty string).
154    
155    20. Debugging a pattern containing \p or \P could cause a crash. For example,
156        [\P{Any}] did so. (Error in the code for printing property names.)
157    
158    21. An orphan \E inside a character class could cause a crash.
159    
160    22. A repeated capturing bracket such as (A)? could cause a wild memory
161        reference during compilation.
162    
163    23. There are several functions in pcre_compile() that scan along a compiled
164        expression for various reasons (e.g. to see if it's fixed length for look
165        behind). There were bugs in these functions when a repeated \p or \P was
166        present in the pattern. These operators have additional parameters compared
167        with \d, etc, and these were not being taken into account when moving along
168        the compiled data. Specifically:
169    
170        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
171            length.
172    
173        (b) An item such as \pL+ within a repeated group could cause crashes or
174            loops.
175    
176        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
177            "reference to non-existent subpattern" error.
178    
179        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
180    
181    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
182        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
183    
184    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
185    
186    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
187        character were causing crashes (broken optimization).
188    
189    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
190        \p or \P) caused a compile-time loop.
191    
192    28. More problems have arisen in unanchored patterns when CRLF is a valid line
193        break. For example, the unstudied pattern [\r\n]A does not match the string
194        "\r\nA" because change 7.0/46 below moves the current point on by two
195        characters after failing to match at the start. However, the pattern \nA
196        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
197        the same is true. There doesn't seem any very clean way out of this, but
198        what I have chosen to do makes the common cases work: PCRE now takes note
199        of whether there can be an explicit match for \r or \n anywhere in the
200        pattern, and if so, 7.0/46 no longer applies. As part of this change,
201        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
202        pattern has explicit CR or LF references.
203    
204    29. Added (*CR) etc for changing newline setting at start of pattern.
205    
206    
207    Version 7.2 19-Jun-07
208    ---------------------
209    
210     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
211        which is apparently normally available under Windows.
212    
213     2. Re-jig the pcregrep tests with different newline settings in an attempt
214        to make them independent of the local environment's newline setting.
215    
216     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
217    
218     4. Some of the "internals" tests were previously cut out when the link size
219        was not 2, because the output contained actual offsets. The recent new
220        "Z" feature of pcretest means that these can be cut out, making the tests
221        usable with all link sizes.
222    
223     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
224        stack recursion. This gives a massive performance boost under BSD, but just
225        a small improvement under Linux. However, it saves one field in the frame
226        in all cases.
227    
228     6. Added more features from the forthcoming Perl 5.10:
229    
230        (a) (?-n) (where n is a string of digits) is a relative subroutine or
231            recursion call. It refers to the nth most recently opened parentheses.
232    
233        (b) (?+n) is also a relative subroutine call; it refers to the nth next
234            to be opened parentheses.
235    
236        (c) Conditions that refer to capturing parentheses can be specified
237            relatively, for example, (?(-2)... or (?(+3)...
238    
239        (d) \K resets the start of the current match so that everything before
240            is not part of it.
241    
242        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
243    
244        (f) \g{name} is another synonym - part of Perl 5.10's unification of
245            reference syntax.
246    
247        (g) (?| introduces a group in which the numbering of parentheses in each
248            alternative starts with the same number.
249    
250        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
251    
252     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
253        PCRE_INFO_JCHANGED.
254    
255     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
256        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
257        for detecting groups that can match an empty string.
258    
259     9. A pattern with a very large number of alternatives (more than several
260        hundred) was running out of internal workspace during the pre-compile
261        phase, where pcre_compile() figures out how much memory will be needed. A
262        bit of new cunning has reduced the workspace needed for groups with
263        alternatives. The 1000-alternative test pattern now uses 12 bytes of
264        workspace instead of running out of the 4096 that are available.
265    
266    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
267    
268    11. Applied patch from Google to remove an optimization that didn't quite work.
269        The report of the bug said:
270    
271          pcrecpp::RE("a*").FullMatch("aaa") matches, while
272          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
273          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
274    
275    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
276        it matched the wrong number of bytes.
277    
278    
279    Version 7.1 24-Apr-07
280    ---------------------
281    
282     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
283        that is more "standard", making use of automake and other Autotools. There
284        is some re-arrangement of the files and adjustment of comments consequent
285        on this.
286    
287     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
288        for recursive directory scanning broke on some systems because the files
289        are not scanned in any specific order and on different systems the order
290        was different. A call to "sort" has been inserted into RunGrepTest for the
291        approprate test as a short-term fix. In the longer term there may be an
292        alternative.
293    
294     3. I had an email from Eric Raymond about problems translating some of PCRE's
295        man pages to HTML (despite the fact that I distribute HTML pages, some
296        people do their own conversions for various reasons). The problems
297        concerned the use of low-level troff macros .br and .in. I have therefore
298        removed all such uses from the man pages (some were redundant, some could
299        be replaced by .nf/.fi pairs). The 132html script that I use to generate
300        HTML has been updated to handle .nf/.fi and to complain if it encounters
301        .br or .in.
302    
303     4. Updated comments in configure.ac that get placed in config.h.in and also
304        arranged for config.h to be included in the distribution, with the name
305        config.h.generic, for the benefit of those who have to compile without
306        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
307    
308     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
309        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
310        makevp.bat for the current PCRE, using the additional files
311        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
312    
313     6. A Windows user reported a minor discrepancy with test 2, which turned out
314        to be caused by a trailing space on an input line that had got lost in his
315        copy. The trailing space was an accident, so I've just removed it.
316    
317     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
318        that is needed.
319    
320     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
321        as "const" (a) because they are and (b) because it helps the PHP
322        maintainers who have recently made a script to detect big data structures
323        in the php code that should be moved to the .rodata section. I remembered
324        to update Builducptable as well, so it won't revert if ucptable.h is ever
325        re-created.
326    
327     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
328        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
329        order to be able to cut out the UTF-8 tables in the latter when UTF-8
330        support is not required. This saves 1.5-2K of code, which is important in
331        some applications.
332    
333        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
334        so as not to refer to the tables, even though these functions will never be
335        called when UTF-8 support is disabled. Otherwise there are problems with a
336        shared library.
337    
338    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
339    
340        (a) It was defining its arguments as char * instead of void *.
341    
342        (b) It was assuming that all moves were upwards in memory; this was true
343            a long time ago when I wrote it, but is no longer the case.
344    
345        The emulated memove() is provided for those environments that have neither
346        memmove() nor bcopy(). I didn't think anyone used it these days, but that
347        is clearly not the case, as these two bugs were recently reported.
348    
349    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
350        and Detrail to create the HTML documentation, the .txt form of the man
351        pages, and it removes trailing spaces from listed files. It also creates
352        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
353        case, it wraps all the #defines with #ifndefs. This script should be run
354        before "make dist".
355    
356    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
357        with Unicode property support.
358    
359        (a) For a maximizing quantifier, if the two different cases of the
360            character were of different lengths in their UTF-8 codings (there are
361            some cases like this - I found 11), and the matching function had to
362            back up over a mixture of the two cases, it incorrectly assumed they
363            were both the same length.
364    
365        (b) When PCRE was configured to use the heap rather than the stack for
366            recursion during matching, it was not correctly preserving the data for
367            the other case of a UTF-8 character when checking ahead for a match
368            while processing a minimizing repeat. If the check also involved
369            matching a wide character, but failed, corruption could cause an
370            erroneous result when trying to check for a repeat of the original
371            character.
372    
373    13. Some tidying changes to the testing mechanism:
374    
375        (a) The RunTest script now detects the internal link size and whether there
376            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
377            values substituted by "configure". (The RunGrepTest script already did
378            this for UTF-8.) The configure.ac script no longer substitutes the
379            relevant variables.
380    
381        (b) The debugging options /B and /D in pcretest show the compiled bytecode
382            with length and offset values. This means that the output is different
383            for different internal link sizes. Test 2 is skipped for link sizes
384            other than 2 because of this, bypassing the problem. Unfortunately,
385            there was also a test in test 3 (the locale tests) that used /B and
386            failed for link sizes other than 2. Rather than cut the whole test out,
387            I have added a new /Z option to pcretest that replaces the length and
388            offset values with spaces. This is now used to make test 3 independent
389            of link size. (Test 2 will be tidied up later.)
390    
391    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
392        segmentation fault instead of returning the appropriate error message.
393    
394    15. In multiline mode when the newline sequence was set to "any", the pattern
395        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
396        This doesn't seem right; it now treats the CRLF combination as the line
397        ending, and so does not match in that case. It's only a pattern such as ^$
398        that would hit this one: something like ^ABC$ would have failed after \r
399        and then tried again after \r\n.
400    
401    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
402        in an attempt to make files that differ only in their line terminators
403        compare equal. This works on Linux.
404    
405    17. Under certain error circumstances pcregrep might try to free random memory
406        as it exited. This is now fixed, thanks to valgrind.
407    
408    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
409        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
410        was because its rules for how to advance for /g after matching an empty
411        string at the end of a line did not allow for this case. They now check for
412        it specially.
413    
414    20. pcretest is supposed to handle patterns and data of any length, by
415        extending its buffers when necessary. It was getting this wrong when the
416        buffer for a data line had to be extended.
417    
418    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
419        CRLF as a newline sequence.
420    
421    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
422        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
423        I have nevertheless tidied it up.
424    
425    23. Added some casts to kill warnings from HP-UX ia64 compiler.
426    
427    24. Added a man page for pcre-config.
428    
429    
430    Version 7.0 19-Dec-06
431    ---------------------
432    
433     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
434        moving to gcc 4.1.1.
435    
436     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
437        sys/time.h, which is documented as needed for this function. It doesn't
438        seem to matter on Linux, but it showed up on some releases of OS X.
439    
440     3. It seems that there are systems where bytes whose values are greater than
441        127 match isprint() in the "C" locale. The "C" locale should be the
442        default when a C program starts up. In most systems, only ASCII printing
443        characters match isprint(). This difference caused the output from pcretest
444        to vary, making some of the tests fail. I have changed pcretest so that:
445    
446        (a) When it is outputting text in the compiled version of a pattern, bytes
447            other than 32-126 are always shown as hex escapes.
448    
449        (b) When it is outputting text that is a matched part of a subject string,
450            it does the same, unless a different locale has been set for the match
451            (using the /L modifier). In this case, it uses isprint() to decide.
452    
453     4. Fixed a major bug that caused incorrect computation of the amount of memory
454        required for a compiled pattern when options that changed within the
455        pattern affected the logic of the preliminary scan that determines the
456        length. The relevant options are -x, and -i in UTF-8 mode. The result was
457        that the computed length was too small. The symptoms of this bug were
458        either the PCRE error "internal error: code overflow" from pcre_compile(),
459        or a glibc crash with a message such as "pcretest: free(): invalid next
460        size (fast)". Examples of patterns that provoked this bug (shown in
461        pcretest format) are:
462    
463          /(?-x: )/x
464          /(?x)(?-x: \s*#\s*)/
465          /((?i)[\x{c0}])/8
466          /(?i:[\x{c0}])/8
467    
468        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
469        is now done differently.
470    
471     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
472        wrapper classes; (b) implement a new function in the C++ scanner that is
473        more efficient than the old way of doing things because it avoids levels of
474        recursion in the regex matching; (c) add a paragraph to the documentation
475        for the FullMatch() function.
476    
477     6. The escape sequence \n was being treated as whatever was defined as
478        "newline". Not only was this contrary to the documentation, which states
479        that \n is character 10 (hex 0A), but it also went horribly wrong when
480        "newline" was defined as CRLF. This has been fixed.
481    
482     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
483        was being set to -1 for the "end of line" case (supposedly a value that no
484        character can have). Though this value is never used (the check for end of
485        line is "zero bytes in current character"), it caused compiler complaints.
486        I've changed it to 0xffffffff.
487    
488     8. In pcre_version.c, the version string was being built by a sequence of
489        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
490        string (as it is for production releases) called a macro with an empty
491        argument. The C standard says the result of this is undefined. The gcc
492        compiler treats it as an empty string (which was what was wanted) but it is
493        reported that Visual C gives an error. The source has been hacked around to
494        avoid this problem.
495    
496     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
497        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
498        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
499        of them did).
500    
501    10. Originally, pcretest opened its input and output without "b"; then I was
502        told that "b" was needed in some environments, so it was added for release
503        5.0 to both the input and output. (It makes no difference on Unix-like
504        systems.) Later I was told that it is wrong for the input on Windows. I've
505        now abstracted the modes into two macros, to make it easier to fiddle with
506        them, and removed "b" from the input mode under Windows.
507    
508    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
509    
510    12. Added -help and --help to pcretest as an official way of being reminded
511        of the options.
512    
513    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
514        and pcrecpp.cc because they annoy compilers at high warning levels.
515    
516    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
517    
518    15. Fixed an occurrence of == in configure.ac that should have been = (shell
519        scripts are not C programs :-) and which was not noticed because it works
520        on Linux.
521    
522    16. pcretest is supposed to handle any length of pattern and data line (as one
523        line or as a continued sequence of lines) by extending its input buffer if
524        necessary. This feature was broken for very long pattern lines, leading to
525        a string of junk being passed to pcre_compile() if the pattern was longer
526        than about 50K.
527    
528    17. I have done a major re-factoring of the way pcre_compile() computes the
529        amount of memory needed for a compiled pattern. Previously, there was code
530        that made a preliminary scan of the pattern in order to do this. That was
531        OK when PCRE was new, but as the facilities have expanded, it has become
532        harder and harder to keep it in step with the real compile phase, and there
533        have been a number of bugs (see for example, 4 above). I have now found a
534        cunning way of running the real compile function in a "fake" mode that
535        enables it to compute how much memory it would need, while actually only
536        ever using a few hundred bytes of working memory and without too many
537        tests of the mode. This should make future maintenance and development
538        easier. A side effect of this work is that the limit of 200 on the nesting
539        depth of parentheses has been removed (though this was never a serious
540        limitation, I suspect). However, there is a downside: pcre_compile() now
541        runs more slowly than before (30% or more, depending on the pattern). I
542        hope this isn't a big issue. There is no effect on runtime performance.
543    
544    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
545        newline (only possible for the last line of a file) and it was a
546        pattern that set a locale (followed by /Lsomething), pcretest crashed.
547    
548    19. Added additional timing features to pcretest. (1) The -tm option now times
549        matching only, not compiling. (2) Both -t and -tm can be followed, as a
550        separate command line item, by a number that specifies the number of
551        repeats to use when timing. The default is 50000; this gives better
552        precision, but takes uncomfortably long for very large patterns.
553    
554    20. Extended pcre_study() to be more clever in cases where a branch of a
555        subpattern has no definite first character. For example, (a*|b*)[cd] would
556        previously give no result from pcre_study(). Now it recognizes that the
557        first character must be a, b, c, or d.
558    
559    21. There was an incorrect error "recursive call could loop indefinitely" if
560        a subpattern (or the entire pattern) that was being tested for matching an
561        empty string contained only one non-empty item after a nested subpattern.
562        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
563        incorrectly, because the \d was being skipped in the check.
564    
565    22. The pcretest program now has a new pattern option /B and a command line
566        option -b, which is equivalent to adding /B to every pattern. This causes
567        it to show the compiled bytecode, without the additional information that
568        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
569        is the same as /B/I).
570    
571    23. A new optimization is now able automatically to treat some sequences such
572        as a*b as a*+b. More specifically, if something simple (such as a character
573        or a simple class like \d) has an unlimited quantifier, and is followed by
574        something that cannot possibly match the quantified thing, the quantifier
575        is automatically "possessified".
576    
577    24. A recursive reference to a subpattern whose number was greater than 39
578        went wrong under certain circumstances in UTF-8 mode. This bug could also
579        have affected the operation of pcre_study().
580    
581    25. Realized that a little bit of performance could be had by replacing
582        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
583    
584    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
585    
586    27. Possessive quantifiers such as a++ were previously implemented by turning
587        them into atomic groups such as ($>a+). Now they have their own opcodes,
588        which improves performance. This includes the automatically created ones
589        from 23 above.
590    
591    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
592        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
593        the first matched character to be a colon. This applied both to named and
594        numbered groups.
595    
596    29. The ucpinternal.h header file was missing its idempotency #ifdef.
597    
598    30. I was sent a "project" file called libpcre.a.dev which I understand makes
599        building PCRE on Windows easier, so I have included it in the distribution.
600    
601    31. There is now a check in pcretest against a ridiculously large number being
602        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
603        loop, the loop is abandoned.
604    
605    32. Forward references to subpatterns in conditions such as (?(2)...) where
606        subpattern 2 is defined later cause pcre_compile() to search forwards in
607        the pattern for the relevant set of parentheses. This search went wrong
608        when there were unescaped parentheses in a character class, parentheses
609        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
610    
611    33. "Subroutine" calls and backreferences were previously restricted to
612        referencing subpatterns earlier in the regex. This restriction has now
613        been removed.
614    
615    34. Added a number of extra features that are going to be in Perl 5.10. On the
616        whole, these are just syntactic alternatives for features that PCRE had
617        previously implemented using the Python syntax or my own invention. The
618        other formats are all retained for compatibility.
619    
620        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
621            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
622            also .NET compatible.
623    
624        (b) A recursion or subroutine call to a named group can now be defined as
625            (?&name) as well as (?P>name).
626    
627        (c) A backreference to a named group can now be defined as \k<name> or
628            \k'name' as well as (?P=name). The new forms, as well as being in Perl
629            5.10, are also .NET compatible.
630    
631        (d) A conditional reference to a named group can now use the syntax
632            (?(<name>) or (?('name') as well as (?(name).
633    
634        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
635            groups (named and numbered) that are never evaluated inline, but can be
636            called as "subroutines" from elsewhere. In effect, the DEFINE condition
637            is always false. There may be only one alternative in such a group.
638    
639        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
640            as the simple (?(R). The condition is true only if the most recent
641            recursion is that of the given number or name. It does not search out
642            through the entire recursion stack.
643    
644        (g) The escape \gN or \g{N} has been added, where N is a positive or
645            negative number, specifying an absolute or relative reference.
646    
647    35. Tidied to get rid of some further signed/unsigned compiler warnings and
648        some "unreachable code" warnings.
649    
650    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
651        things, this adds five new scripts.
652    
653    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
654        There were also incompatibilities regarding the handling of \Q..\E inside
655        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
656        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
657    
658    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
659        matches an empty string, and forcibly breaks the loop. There were bugs in
660        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
661        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
662        separate and independent bugs (that affected different cases) have been
663        fixed.
664    
665    39. Refactored the code to abolish the use of different opcodes for small
666        capturing bracket numbers. This is a tidy that I avoided doing when I
667        removed the limit on the number of capturing brackets for 3.5 back in 2001.
668        The new approach is not only tidier, it makes it possible to reduce the
669        memory needed to fix the previous bug (38).
670    
671    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
672        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
673        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
674        mode.
675    
676    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
677        report.
678    
679    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
680        copy construction and assignment in the C++ wrapper.
681    
682    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
683        couple of bugs that could have given wrong results in the "--newline=crlf"
684        case.
685    
686    44. Added a number of casts and did some reorganization of signed/unsigned int
687        variables following suggestions from Dair Grant. Also renamed the variable
688        "this" as "item" because it is a C++ keyword.
689    
690    45. Arranged for dftables to add
691    
692          #include "pcre_internal.h"
693    
694        to pcre_chartables.c because without it, gcc 4.x may remove the array
695        definition from the final binary if PCRE is built into a static library and
696        dead code stripping is activated.
697    
698    46. For an unanchored pattern, if a match attempt fails at the start of a
699        newline sequence, and the newline setting is CRLF or ANY, and the next two
700        characters are CRLF, advance by two characters instead of one.
701    
702    
703    Version 6.7 04-Jul-06
704    ---------------------
705    
706     1. In order to handle tests when input lines are enormously long, pcretest has
707        been re-factored so that it automatically extends its buffers when
708        necessary. The code is crude, but this _is_ just a test program. The
709        default size has been increased from 32K to 50K.
710    
711     2. The code in pcre_study() was using the value of the re argument before
712        testing it for NULL. (Of course, in any sensible call of the function, it
713        won't be NULL.)
714    
715     3. The memmove() emulation function in pcre_internal.h, which is used on
716        systems that lack both memmove() and bcopy() - that is, hardly ever -
717        was missing a "static" storage class specifier.
718    
719     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
720        containing an extended class (one that cannot be represented by a bitmap
721        because it contains high-valued characters or Unicode property items, e.g.
722        [\pZ]). Almost always one would set UTF-8 mode when processing such a
723        pattern, but PCRE should not loop if you do not (it no longer does).
724        [Detail: two cases were found: (a) a repeated subpattern containing an
725        extended class; (b) a recursive reference to a subpattern that followed a
726        previous extended class. It wasn't skipping over the extended class
727        correctly when UTF-8 mode was not set.]
728    
729     5. A negated single-character class was not being recognized as fixed-length
730        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
731        compile error "lookbehind assertion is not fixed length".
732    
733     6. The RunPerlTest auxiliary script was showing an unexpected difference
734        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
735        write a Perl script that can interpret lines of an input file either as
736        byte characters or as UTF-8, which is what "perltest" was being required to
737        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
738        can't do is switch easily at run time between having the "use utf8;" pragma
739        or not. In the end, I fudged it by using the RunPerlTest script to insert
740        "use utf8;" explicitly for the UTF-8 tests.
741    
742     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
743        the end of the subject string, contrary to the documentation and to what
744        Perl does. This was true of both matching functions. Now it matches only at
745        the start of the subject and immediately after *internal* newlines.
746    
747     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
748        a pointer to an int instead of a pointer to an unsigned long int. This
749        caused problems on 64-bit systems.
750    
751     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
752        instance of the 'standard' template library not being so standard".
753    
754    10. There was no check on the number of named subpatterns nor the maximum
755        length of a subpattern name. The product of these values is used to compute
756        the size of the memory block for a compiled pattern. By supplying a very
757        long subpattern name and a large number of named subpatterns, the size
758        computation could be caused to overflow. This is now prevented by limiting
759        the length of names to 32 characters, and the number of named subpatterns
760        to 10,000.
761    
762    11. Subpatterns that are repeated with specific counts have to be replicated in
763        the compiled pattern. The size of memory for this was computed from the
764        length of the subpattern and the repeat count. The latter is limited to
765        65535, but there was no limit on the former, meaning that integer overflow
766        could in principle occur. The compiled length of a repeated subpattern is
767        now limited to 30,000 bytes in order to prevent this.
768    
769    12. Added the optional facility to have named substrings with the same name.
770    
771    13. Added the ability to use a named substring as a condition, using the
772        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
773        are numbers (not recommended). Forward references are permitted.
774    
775    14. Added forward references in named backreferences (if you see what I mean).
776    
777    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
778        pattern could run off the end of the subject. For example, the pattern
779        "(?s)(.{1,5})"8 did this with the subject "ab".
780    
781    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
782        PCRE_CASELESS was set when matching characters that were quantified with ?
783        or *.
784    
785    17. A character class other than a single negated character that had a minimum
786        but no maximum quantifier - for example [ab]{6,} - was not handled
787        correctly by pce_dfa_exec(). It would match only one character.
788    
789    18. A valid (though odd) pattern that looked like a POSIX character
790        class but used an invalid character after [ (for example [[,abc,]]) caused
791        pcre_compile() to give the error "Failed: internal error: code overflow" or
792        in some cases to crash with a glibc free() error. This could even happen if
793        the pattern terminated after [[ but there just happened to be a sequence of
794        letters, a binary zero, and a closing ] in the memory that followed.
795    
796    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
797        over the years. Originally (before any Unicode support), just the bottom 8
798        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
799        output from "man perlunicode" includes this:
800    
801          The regular expression compiler produces polymorphic opcodes.  That
802          is, the pattern adapts to the data and automatically switches to
803          the Unicode character scheme when presented with Unicode data--or
804          instead uses a traditional byte scheme when presented with byte
805          data.
806    
807        Sadly, a wide octal escape does not cause a switch, and in a string with
808        no other multibyte characters, these octal escapes are treated as before.
809        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
810        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
811        Unicode string.
812    
813        I have not perpetrated such confusion in PCRE. Up till now, it took just
814        the bottom 8 bits, as in old Perl. I have now made octal escapes with
815        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
816        translate to the appropriate multibyte character.
817    
818    29. Applied some refactoring to reduce the number of warnings from Microsoft
819        and Borland compilers. This has included removing the fudge introduced
820        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
821        a warning about an unused variable.
822    
823    21. PCRE has not included VT (character 0x0b) in the set of whitespace
824        characters since release 4.0, because Perl (from release 5.004) does not.
825        [Or at least, is documented not to: some releases seem to be in conflict
826        with the documentation.] However, when a pattern was studied with
827        pcre_study() and all its branches started with \s, PCRE still included VT
828        as a possible starting character. Of course, this did no harm; it just
829        caused an unnecessary match attempt.
830    
831    22. Removed a now-redundant internal flag bit that recorded the fact that case
832        dependency changed within the pattern. This was once needed for "required
833        byte" processing, but is no longer used. This recovers a now-scarce options
834        bit. Also moved the least significant internal flag bit to the most-
835        significant bit of the word, which was not previously used (hangover from
836        the days when it was an int rather than a uint) to free up another bit for
837        the future.
838    
839    23. Added support for CRLF line endings as well as CR and LF. As well as the
840        default being selectable at build time, it can now be changed at runtime
841        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
842        specify that it is scanning data with non-default line endings.
843    
844    24. Changed the definition of CXXLINK to make it agree with the definition of
845        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
846    
847    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
848        recursions. This makes a big different to stack usage for some patterns.
849    
850    26. If a subpattern containing a named recursion or subroutine reference such
851        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
852        the space required for the compiled pattern went wrong and gave too small a
853        value. Depending on the environment, this could lead to "Failed: internal
854        error: code overflow at offset 49" or "glibc detected double free or
855        corruption" errors.
856    
857    27. Applied patches from Google (a) to support the new newline modes and (b) to
858        advance over multibyte UTF-8 characters in GlobalReplace.
859    
860    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
861        difference for some implementation of PCRE in some Windows version.
862    
863    29. Added some extra testing facilities to pcretest:
864    
865        \q<number>   in a data line sets the "match limit" value
866        \Q<number>   in a data line sets the "match recursion limt" value
867        -S <number>  sets the stack size, where <number> is in megabytes
868    
869        The -S option isn't available for Windows.
870    
871    
872    Version 6.6 06-Feb-06
873    ---------------------
874    
875     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
876        in pcreposix.h. I have copied the definition from pcre.h.
877    
878     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
879        because pcre.h is no longer a built file.
880    
881     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
882        not normally included in the compiled code.
883    
884    
885    Version 6.5 01-Feb-06
886    ---------------------
887    
888     1. When using the partial match feature with pcre_dfa_exec(), it was not
889        anchoring the second and subsequent partial matches at the new starting
890        point. This could lead to incorrect results. For example, with the pattern
891        /1234/, partially matching against "123" and then "a4" gave a match.
892    
893     2. Changes to pcregrep:
894    
895        (a) All non-match returns from pcre_exec() were being treated as failures
896            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
897            error message is output. Some extra information is given for the
898            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
899            probably the only errors that are likely to be caused by users (by
900            specifying a regex that has nested indefinite repeats, for instance).
901            If there are more than 20 of these errors, pcregrep is abandoned.
902    
903        (b) A binary zero was treated as data while matching, but terminated the
904            output line if it was written out. This has been fixed: binary zeroes
905            are now no different to any other data bytes.
906    
907        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
908            used to set a locale for matching. The --locale=xxxx long option has
909            been added (no short equivalent) to specify a locale explicitly on the
910            pcregrep command, overriding the environment variables.
911    
912        (d) When -B was used with -n, some line numbers in the output were one less
913            than they should have been.
914    
915        (e) Added the -o (--only-matching) option.
916    
917        (f) If -A or -C was used with -c (count only), some lines of context were
918            accidentally printed for the final match.
919    
920        (g) Added the -H (--with-filename) option.
921    
922        (h) The combination of options -rh failed to suppress file names for files
923            that were found from directory arguments.
924    
925        (i) Added the -D (--devices) and -d (--directories) options.
926    
927        (j) Added the -F (--fixed-strings) option.
928    
929        (k) Allow "-" to be used as a file name for -f as well as for a data file.
930    
931        (l) Added the --colo(u)r option.
932    
933        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
934            is not present by default.
935    
936     3. A nasty bug was discovered in the handling of recursive patterns, that is,
937        items such as (?R) or (?1), when the recursion could match a number of
938        alternatives. If it matched one of the alternatives, but subsequently,
939        outside the recursion, there was a failure, the code tried to back up into
940        the recursion. However, because of the way PCRE is implemented, this is not
941        possible, and the result was an incorrect result from the match.
942    
943        In order to prevent this happening, the specification of recursion has
944        been changed so that all such subpatterns are automatically treated as
945        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
946    
947     4. I had overlooked the fact that, in some locales, there are characters for
948        which isalpha() is true but neither isupper() nor islower() are true. In
949        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
950        and ordfeminine) are like this. This affected the treatment of \w and \W
951        when they appeared in character classes, but not when they appeared outside
952        a character class. The bit map for "word" characters is now created
953        separately from the results of isalnum() instead of just taking it from the
954        upper, lower, and digit maps. (Plus the underscore character, of course.)
955    
956     5. The above bug also affected the handling of POSIX character classes such as
957        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
958        permanent tables. Instead, the bit maps for such a class were previously
959        created as the appropriate unions of the upper, lower, and digit bitmaps.
960        Now they are created by subtraction from the [[:word:]] class, which has
961        its own bitmap.
962    
963     6. The [[:blank:]] character class matches horizontal, but not vertical space.
964        It is created by subtracting the vertical space characters (\x09, \x0a,
965        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
966        subtraction was done in the overall bitmap for a character class, meaning
967        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
968        be recognized. This bug has been fixed.
969    
970     7. Patches from the folks at Google:
971    
972          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
973          real life, but is still worth protecting against".
974    
975          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
976          regular expressions".
977    
978          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
979          have it.
980    
981          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
982          "configure" and the latter not, in order to fix a problem somebody had
983          with compiling the Arg class on HP-UX.
984    
985          (e) Improve the error-handling of the C++ wrapper a little bit.
986    
987          (f) New tests for checking recursion limiting.
988    
989     8. The pcre_memmove() function, which is used only if the environment does not
990        have a standard memmove() function (and is therefore rarely compiled),
991        contained two bugs: (a) use of int instead of size_t, and (b) it was not
992        returning a result (though PCRE never actually uses the result).
993    
994     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
995        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
996        returned instead of calling malloc() with an overflowing number that would
997        most likely cause subsequent chaos.
998    
999    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1000    
1001    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1002        with this option is matched, the nmatch and pmatch options of regexec() are
1003        ignored.
1004    
1005    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1006        provided in case anyone wants to the the POSIX interface with UTF-8
1007        strings.
1008    
1009    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1010        C++ linking (needed for some HP-UX environments).
1011    
1012    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1013        (unused parameter) and in the pcre_printint() function (omitted "default"
1014        switch label when the default is to do nothing).
1015    
1016    15. Added some code to make it possible, when PCRE is compiled as a C++
1017        library, to replace subject pointers for pcre_exec() with a smart pointer
1018        class, thus making it possible to process discontinuous strings.
1019    
1020    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1021        much the same function. They were added by different people who were trying
1022        to make PCRE easy to compile on non-Unix systems. It has been suggested
1023        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1024        for compiling on Windows systems. I have therefore replaced it with
1025        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1026        defaults to "extern" for C or "extern C" for C++, which works fine on
1027        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1028        SCOPE with something explicit in config.h. In addition:
1029    
1030        (a) pcreposix.h still had just "extern" instead of either of these macros;
1031            I have replaced it with PCRE_DATA_SCOPE.
1032    
1033        (b) Functions such as _pcre_xclass(), which are internal to the library,
1034            but external in the C sense, all had PCRE_EXPORT in their definitions.
1035            This is apparently wrong for the Windows case, so I have removed it.
1036            (It makes no difference on Unix-like systems.)
1037    
1038    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1039        of recursive calls to match(). This is different to MATCH_LIMIT because
1040        that limits the total number of calls to match(), not all of which increase
1041        the depth of recursion. Limiting the recursion depth limits the amount of
1042        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1043        when PCRE is compiled, and changed at run time. A patch from Google adds
1044        this functionality to the C++ interface.
1045    
1046    18. Changes to the handling of Unicode character properties:
1047    
1048        (a) Updated the table to Unicode 4.1.0.
1049    
1050        (b) Recognize characters that are not in the table as "Cn" (undefined).
1051    
1052        (c) I revised the way the table is implemented to a much improved format
1053            which includes recognition of ranges. It now supports the ranges that
1054            are defined in UnicodeData.txt, and it also amalgamates other
1055            characters into ranges. This has reduced the number of entries in the
1056            table from around 16,000 to around 3,000, thus reducing its size
1057            considerably. I realized I did not need to use a tree structure after
1058            all - a binary chop search is just as efficient. Having reduced the
1059            number of entries, I extended their size from 6 bytes to 8 bytes to
1060            allow for more data.
1061    
1062        (d) Added support for Unicode script names via properties such as \p{Han}.
1063    
1064    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1065        matching that character.
1066    
1067    20. When matching a repeated Unicode property with a minimum greater than zero,
1068        (for example \pL{2,}), PCRE could look past the end of the subject if it
1069        reached it while seeking the minimum number of characters. This could
1070        happen only if some of the characters were more than one byte long, because
1071        there is a check for at least the minimum number of bytes.
1072    
1073    21. Refactored the implementation of \p and \P so as to be more general, to
1074        allow for more different types of property in future. This has changed the
1075        compiled form incompatibly. Anybody with saved compiled patterns that use
1076        \p or \P will have to recompile them.
1077    
1078    22. Added "Any" and "L&" to the supported property types.
1079    
1080    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1081        but give a compile time error if the value is greater than 0xff.
1082    
1083    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1084        accidentally not being installed or uninstalled.
1085    
1086    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1087        made were to insert the current release number. This seemed silly, because
1088        it made things harder for people building PCRE on systems that don't run
1089        "configure". I have turned pcre.h into a distributed file, no longer built
1090        by "configure", with the version identification directly included. There is
1091        no longer a pcre.h.in file.
1092    
1093        However, this change necessitated a change to the pcre-config script as
1094        well. It is built from pcre-config.in, and one of the substitutions was the
1095        release number. I have updated configure.ac so that ./configure now finds
1096        the release number by grepping pcre.h.
1097    
1098    26. Added the ability to run the tests under valgrind.
1099    
1100    
1101    Version 6.4 05-Sep-05
1102    ---------------------
1103    
1104     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1105        "--" to be printed when multiple files were scanned, even when none of the
1106        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1107        consider it to be a bug, and have restored the previous behaviour.
1108    
1109     2. A couple of code tidies to get rid of compiler warnings.
1110    
1111     3. The pcretest program used to cheat by referring to symbols in the library
1112        whose names begin with _pcre_. These are internal symbols that are not
1113        really supposed to be visible externally, and in some environments it is
1114        possible to suppress them. The cheating is now confined to including
1115        certain files from the library's source, which is a bit cleaner.
1116    
1117     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1118        file's purpose clearer.
1119    
1120     5. Reorganized pcre_ucp_findchar().
1121    
1122    
1123    Version 6.3 15-Aug-05
1124    ---------------------
1125    
1126     1. The file libpcre.pc.in did not have general read permission in the tarball.
1127    
1128     2. There were some problems when building without C++ support:
1129    
1130        (a) If C++ support was not built, "make install" and "make test" still
1131            tried to test it.
1132    
1133        (b) There were problems when the value of CXX was explicitly set. Some
1134            changes have been made to try to fix these, and ...
1135    
1136        (c) --disable-cpp can now be used to explicitly disable C++ support.
1137    
1138        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1139            backslash in a target when C++ was disabled. This confuses some
1140            versions of "make", apparently. Using an intermediate variable solves
1141            this. (Same for CPP_LOBJ.)
1142    
1143     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1144        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1145        necessary on certain architectures.
1146    
1147     4. Added a setting of -export-symbols-regex to the link command to remove
1148        those symbols that are exported in the C sense, but actually are local
1149        within the library, and not documented. Their names all begin with
1150        "_pcre_". This is not a perfect job, because (a) we have to except some
1151        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1152        available (and never for static libraries). I have made a note to try to
1153        find a way round (a) in the future.
1154    
1155    
1156    Version 6.2 01-Aug-05
1157    ---------------------
1158    
1159     1. There was no test for integer overflow of quantifier values. A construction
1160        such as {1111111111111111} would give undefined results. What is worse, if
1161        a minimum quantifier for a parenthesized subpattern overflowed and became
1162        negative, the calculation of the memory size went wrong. This could have
1163        led to memory overwriting.
1164    
1165     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1166    
1167     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1168        operating environments where this matters.
1169    
1170     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1171        PCRE options from within the C++ wrapper.
1172    
1173     5. Named capturing subpatterns were not being correctly counted when a pattern
1174        was compiled. This caused two problems: (a) If there were more than 100
1175        such subpatterns, the calculation of the memory needed for the whole
1176        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1177        back references of the form \12, where the number was greater than 9, were
1178        not recognized as back references, even though there were sufficient
1179        previous subpatterns.
1180    
1181     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1182        versions of gcc, e.g. 2.95.4.
1183    
1184    
1185    Version 6.1 21-Jun-05
1186    ---------------------
1187    
1188     1. There was one reference to the variable "posix" in pcretest.c that was not
1189        surrounded by "#if !defined NOPOSIX".
1190    
1191     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1192        the cross-check on the old pcre_info() function, for the benefit of the
1193        cut-down version of PCRE that is currently imported into Exim.
1194    
1195     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1196        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1197        patterns that start (?i) but I don't think that matters. The use of (?i) is
1198        just an example; this all applies to the other options as well.
1199    
1200     4. Since libtool seems to echo the compile commands it is issuing, the output
1201        from "make" can be reduced a bit by putting "@" in front of each libtool
1202        compile command.
1203    
1204     5. Patch from the folks at Google for configure.in to be a bit more thorough
1205        in checking for a suitable C++ installation before trying to compile the
1206        C++ stuff. This should fix a reported problem when a compiler was present,
1207        but no suitable headers.
1208    
1209     6. The man pages all had just "PCRE" as their title. I have changed them to
1210        be the relevant file name. I have also arranged that these names are
1211        retained in the file doc/pcre.txt, which is a concatenation in text format
1212        of all the man pages except the little individual ones for each function.
1213    
1214     7. The NON-UNIX-USE file had not been updated for the different set of source
1215        files that come with release 6. I also added a few comments about the C++
1216        wrapper.
1217    
1218    
1219    Version 6.0 07-Jun-05
1220    ---------------------
1221    
1222     1. Some minor internal re-organization to help with my DFA experiments.
1223    
1224     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1225        didn't matter for the library itself when fully configured, but did matter
1226        when compiling without UCP support, or within Exim, where the ucp files are
1227        not imported.
1228    
1229     3. Refactoring of the library code to split up the various functions into
1230        different source modules. The addition of the new DFA matching code (see
1231        below) to a single monolithic source would have made it really too
1232        unwieldy, quite apart from causing all the code to be include in a
1233        statically linked application, when only some functions are used. This is
1234        relevant even without the DFA addition now that patterns can be compiled in
1235        one application and matched in another.
1236    
1237        The downside of splitting up is that there have to be some external
1238        functions and data tables that are used internally in different modules of
1239        the library but which are not part of the API. These have all had their
1240        names changed to start with "_pcre_" so that they are unlikely to clash
1241        with other external names.
1242    
1243     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1244        a different (DFA) algorithm. Although it is slower than the original
1245        function, it does have some advantages for certain types of matching
1246        problem.
1247    
1248     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1249        including restarting after a partial match.
1250    
1251     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1252        defined when compiling for Windows was sent to me. I have put it into the
1253        code, though I have no means of testing or verifying it.
1254    
1255     7. Added the pcre_refcount() auxiliary function.
1256    
1257     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1258        match before or at the first newline in the subject string. In pcretest,
1259        the /f option on a pattern can be used to set this.
1260    
1261     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1262        would behave wrongly. This has been present in PCRE since release 4.0.
1263    
1264    10. A number of changes to the pcregrep command:
1265    
1266        (a) Refactored how -x works; insert ^(...)$ instead of setting
1267            PCRE_ANCHORED and checking the length, in preparation for adding
1268            something similar for -w.
1269    
1270        (b) Added the -w (match as a word) option.
1271    
1272        (c) Refactored the way lines are read and buffered so as to have more
1273            than one at a time available.
1274    
1275        (d) Implemented a pcregrep test script.
1276    
1277        (e) Added the -M (multiline match) option. This allows patterns to match
1278            over several lines of the subject. The buffering ensures that at least
1279            8K, or the rest of the document (whichever is the shorter) is available
1280            for matching (and similarly the previous 8K for lookbehind assertions).
1281    
1282        (f) Changed the --help output so that it now says
1283    
1284              -w, --word-regex(p)
1285    
1286            instead of two lines, one with "regex" and the other with "regexp"
1287            because that confused at least one person since the short forms are the
1288            same. (This required a bit of code, as the output is generated
1289            automatically from a table. It wasn't just a text change.)
1290    
1291        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1292            option but starts with a hyphen. Could be a pattern or a path name
1293            starting with a hyphen, for instance.
1294    
1295        (h) "-" can be given as a file name to represent stdin.
1296    
1297        (i) When file names are being printed, "(standard input)" is used for
1298            the standard input, for compatibility with GNU grep. Previously
1299            "<stdin>" was used.
1300    
1301        (j) The option --label=xxx can be used to supply a name to be used for
1302            stdin when file names are being printed. There is no short form.
1303    
1304        (k) Re-factored the options decoding logic because we are going to add
1305            two more options that take data. Such options can now be given in four
1306            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1307    
1308        (l) Added the -A, -B, and -C options for requesting that lines of context
1309            around matches be printed.
1310    
1311        (m) Added the -L option to print the names of files that do not contain
1312            any matching lines, that is, the complement of -l.
1313    
1314        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1315            continue to scan other files.
1316    
1317        (o) The -s option was incorrectly implemented. For compatibility with other
1318            greps, it now suppresses the error message for a non-existent or non-
1319            accessible file (but not the return code). There is a new option called
1320            -q that suppresses the output of matching lines, which was what -s was
1321            previously doing.
1322    
1323        (p) Added --include and --exclude options to specify files for inclusion
1324            and exclusion when recursing.
1325    
1326    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1327        Hopefully, it now does.
1328    
1329    12. Missing cast in pcre_study().
1330    
1331    13. Added an "uninstall" target to the makefile.
1332    
1333    14. Replaced "extern" in the function prototypes in Makefile.in with
1334        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1335        world, but is set differently for Windows.
1336    
1337    15. Added a second compiling function called pcre_compile2(). The only
1338        difference is that it has an extra argument, which is a pointer to an
1339        integer error code. When there is a compile-time failure, this is set
1340        non-zero, in addition to the error test pointer being set to point to an
1341        error message. The new argument may be NULL if no error number is required
1342        (but then you may as well call pcre_compile(), which is now just a
1343        wrapper). This facility is provided because some applications need a
1344        numeric error indication, but it has also enabled me to tidy up the way
1345        compile-time errors are handled in the POSIX wrapper.
1346    
1347    16. Added VPATH=.libs to the makefile; this should help when building with one
1348        prefix path and installing with another. (Or so I'm told by someone who
1349        knows more about this stuff than I do.)
1350    
1351    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1352        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1353        match everything, including newlines. This is not POSIX-compatible, but
1354        somebody wanted the feature. From pcretest it can be activated by using
1355        both the P and the s flags.
1356    
1357    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1358    
1359    19. libpcre.pc was being incorrectly installed as executable.
1360    
1361    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1362        it now also looks for '\r' so that it will work unmodified on Windows.
1363    
1364    21. Added Google's contributed C++ wrapper to the distribution.
1365    
1366    22. Added some untidy missing memory free() calls in pcretest, to keep
1367        Electric Fence happy when testing.
1368    
1369    
1370    
1371    Version 5.0 13-Sep-04
1372    ---------------------
1373    
1374     1. Internal change: literal characters are no longer packed up into items
1375        containing multiple characters in a single byte-string. Each character
1376        is now matched using a separate opcode. However, there may be more than one
1377        byte in the character in UTF-8 mode.
1378    
1379     2. The pcre_callout_block structure has two new fields: pattern_position and
1380        next_item_length. These contain the offset in the pattern to the next match
1381        item, and its length, respectively.
1382    
1383     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1384        insertion of callouts before each pattern item. Added the /C option to
1385        pcretest to make use of this.
1386    
1387     4. On the advice of a Windows user, the lines
1388    
1389          #if defined(_WIN32) || defined(WIN32)
1390          _setmode( _fileno( stdout ), 0x8000 );
1391          #endif  /* defined(_WIN32) || defined(WIN32) */
1392    
1393        have been added to the source of pcretest. This apparently does useful
1394        magic in relation to line terminators.
1395    
1396     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1397        for the benefit of those environments where the "b" makes a difference.
1398    
1399     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1400        to know about it. I have put a hack into configure.in that adds in code
1401        to set GCC=yes if CC=icc. This seems to end up at a point in the
1402        generated configure script that is early enough to affect the setting of
1403        compiler options, which is what is needed, but I have no means of testing
1404        whether it really works. (The user who reported this had patched the
1405        generated configure script, which of course I cannot do.)
1406    
1407        LATER: After change 22 below (new libtool files), the configure script
1408        seems to know about icc (and also ecc). Therefore, I have commented out
1409        this hack in configure.in.
1410    
1411     7. Added support for pkg-config (2 patches were sent in).
1412    
1413     8. Negated POSIX character classes that used a combination of internal tables
1414        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1415        [[:^ascii]]. Typically, they would match almost any characters. The other
1416        POSIX classes were not broken in this way.
1417    
1418     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1419        to find the match, as PCRE was deluded into thinking that the match had to
1420        start at the start point or following a newline. The same bug applied to
1421        patterns with negative forward assertions or any backward assertions
1422        preceding ".*" at the start, unless the pattern required a fixed first
1423        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1424    
1425    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1426        starting at the last subject character, bytes beyond the end of the subject
1427        string were read.
1428    
1429    11. Renamed the variable "class" as "classbits" to make life easier for C++
1430        users. (Previously there was a macro definition, but it apparently wasn't
1431        enough.)
1432    
1433    12. Added the new field "tables" to the extra data so that tables can be passed
1434        in at exec time, or the internal tables can be re-selected. This allows
1435        a compiled regex to be saved and re-used at a later time by a different
1436        program that might have everything at different addresses.
1437    
1438    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1439        -R library as well as a -L library.
1440    
1441    14. The debugging options of pcretest (-d on the command line or D on a
1442        pattern) showed incorrect output for anything following an extended class
1443        that contained multibyte characters and which was followed by a quantifier.
1444    
1445    15. Added optional support for general category Unicode character properties
1446        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1447        support. It adds about 90K to the size of the library. The meanings of the
1448        inbuilt class escapes such as \d and \s have NOT been changed.
1449    
1450    16. Updated pcredemo.c to include calls to free() to release the memory for the
1451        compiled pattern.
1452    
1453    17. The generated file chartables.c was being created in the source directory
1454        instead of in the building directory. This caused the build to fail if the
1455        source directory was different from the building directory, and was
1456        read-only.
1457    
1458    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1459        file. No doubt somebody will tell me if they don't make sense... Also added
1460        Dan Mooney's comments about building on OpenVMS.
1461    
1462    19. Added support for partial matching via the PCRE_PARTIAL option for
1463        pcre_exec() and the \P data escape in pcretest.
1464    
1465    20. Extended pcretest with 3 new pattern features:
1466    
1467        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1468              write the compiled pattern to the file whose name is "rest-of-line".
1469              This is a straight binary dump of the data, with the saved pointer to
1470              the character tables forced to be NULL. The study data, if any, is
1471              written too. After writing, pcretest reads a new pattern.
1472    
1473        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1474              compiled pattern from the given file. There must not be any
1475              occurrences of "<" in the file name (pretty unlikely); if there are,
1476              pcretest will instead treat the initial "<" as a pattern delimiter.
1477              After reading in the pattern, pcretest goes on to read data lines as
1478              usual.
1479    
1480        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1481              and 16-bit fields in a compiled pattern, to simulate a pattern that
1482              was compiled on a host of opposite endianness.
1483    
1484    21. The pcre-exec() function can now cope with patterns that were compiled on
1485        hosts of opposite endianness, with this restriction:
1486    
1487          As for any compiled expression that is saved and used later, the tables
1488          pointer field cannot be preserved; the extra_data field in the arguments
1489          to pcre_exec() should be used to pass in a tables address if a value
1490          other than the default internal tables were used at compile time.
1491    
1492    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1493        now diagnosed as an error. Previously, most of the time, a negative number
1494        would have been treated as zero, but if in addition "ovector" was passed as
1495        NULL, a crash could occur.
1496    
1497    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1498        new versions from the libtool 1.5 distribution (the last one is a copy of
1499        a file called libtool.m4). This seems to have fixed the need to patch
1500        "configure" to support Darwin 1.3 (which I used to do). However, I still
1501        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1502        workstation).
1503    
1504    24. Changed the PCRE licence to be the more standard "BSD" licence.
1505    
1506    
1507    Version 4.5 01-Dec-03
1508    ---------------------
1509    
1510     1. There has been some re-arrangement of the code for the match() function so
1511        that it can be compiled in a version that does not call itself recursively.
1512        Instead, it keeps those local variables that need separate instances for
1513        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1514        needs to "recurse". Keeping track of where control must go is done by means
1515        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1516        hide most of the details from the main code, and operates only if
1517        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1518        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1519        operating.
1520    
1521        To make it easier for callers to provide specially tailored get/free
1522        functions for this usage, two new functions, pcre_stack_malloc, and
1523        pcre_stack_free, are used. They are always called in strict stacking order,
1524        and the size of block requested is always the same.
1525    
1526        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1527        PCRE has been compiled to use the stack or the heap for recursion. The
1528        -C option of pcretest uses this to show which version is compiled.
1529    
1530        A new data escape \S, is added to pcretest; it causes the amounts of store
1531        obtained and freed by both kinds of malloc/free at match time to be added
1532        to the output.
1533    
1534     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1535        what's available on my current Linux desktop machine.
1536    
1537     3. When matching a UTF-8 string, the test for a valid string at the start has
1538        been extended. If start_offset is not zero, PCRE now checks that it points
1539        to a byte that is the start of a UTF-8 character. If not, it returns
1540        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1541        this is necessary because there may be backward assertions in the pattern.
1542        When matching the same subject several times, it may save resources to use
1543        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1544    
1545     4. The code for checking the validity of UTF-8 strings has been tightened so
1546        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1547        containing "overlong sequences".
1548    
1549     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1550        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1551        should have been "&", but it just so happened that all the cases this let
1552        through by mistake were picked up later in the function.
1553    
1554     6. I had used a variable called "isblank" - this is a C99 function, causing
1555        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1556    
1557     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1558        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1559        so the version is shown; (c) stop "make test" echoing "./RunTest".
1560    
1561     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1562    
1563     9. The prototype for memmove() for systems that don't have it was using
1564        size_t, but the inclusion of the header that defines size_t was later. I've
1565        moved the #includes for the C headers earlier to avoid this.
1566    
1567    10. Added some adjustments to the code to make it easier to compiler on certain
1568        special systems:
1569    
1570          (a) Some "const" qualifiers were missing.
1571          (b) Added the macro EXPORT before all exported functions; by default this
1572              is defined to be empty.
1573          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1574              that it reads its output file name as an argument instead of writing
1575              to the standard output and assuming this can be redirected.
1576    
1577    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1578        class containing characters with values greater than 255, PCRE compilation
1579        went into a loop.
1580    
1581    12. A recursive reference to a subpattern that was within another subpattern
1582        that had a minimum quantifier of zero caused PCRE to crash. For example,
1583        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1584        recursion. If the recursively-called subpattern itself had a zero repeat,
1585        that was OK.
1586    
1587    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1588        buffer into which it was copied (for escape processing) was still set at
1589        1024, so long lines caused crashes.
1590    
1591    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1592        "internal error: code overflow...". This applied to any character class
1593        that was followed by a possessive quantifier.
1594    
1595    15. Modified the Makefile to add libpcre.la as a prerequisite for
1596        libpcreposix.la because I was told this is needed for a parallel build to
1597        work.
1598    
1599    16. If a pattern that contained .* following optional items at the start was
1600        studied, the wrong optimizing data was generated, leading to matching
1601        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1602        matching string must start with a or b or c. The correct conclusion for
1603        this pattern is that a match can start with any character.
1604    
1605    
1606    Version 4.4 13-Aug-03
1607    ---------------------
1608    
1609     1. In UTF-8 mode, a character class containing characters with values between
1610        127 and 255 was not handled correctly if the compiled pattern was studied.
1611        In fixing this, I have also improved the studying algorithm for such
1612        classes (slightly).
1613    
1614     2. Three internal functions had redundant arguments passed to them. Removal
1615        might give a very teeny performance improvement.
1616    
1617     3. Documentation bug: the value of the capture_top field in a callout is *one
1618        more than* the number of the hightest numbered captured substring.
1619    
1620     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1621        in incorrectly linking with a previously installed version. They now link
1622        explicitly with libpcre.la.
1623    
1624     5. configure.in no longer needs to recognize Cygwin specially.
1625    
1626     6. A problem in pcre.in for Windows platforms is fixed.
1627    
1628     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1629        pcretest, it used to include the size of the study block as part of its
1630        output. Unfortunately, the structure contains a field that has a different
1631        size on different hardware architectures. This meant that the tests that
1632        showed this size failed. As the block is currently always of a fixed size,
1633        this information isn't actually particularly useful in pcretest output, so
1634        I have just removed it.
1635    
1636     8. Three pre-processor statements accidentally did not start in column 1.
1637        Sadly, there are *still* compilers around that complain, even though
1638        standard C has not required this for well over a decade. Sigh.
1639    
1640     9. In pcretest, the code for checking callouts passed small integers in the
1641        callout_data field, which is a void * field. However, some picky compilers
1642        complained about the casts involved for this on 64-bit systems. Now
1643        pcretest passes the address of the small integer instead, which should get
1644        rid of the warnings.
1645    
1646    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1647        both compile and run time, and gives an error if an invalid UTF-8 sequence
1648        is found. There is a option for disabling this check in cases where the
1649        string is known to be correct and/or the maximum performance is wanted.
1650    
1651    11. In response to a bug report, I changed one line in Makefile.in from
1652    
1653            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1654        to
1655            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1656    
1657        to look similar to other lines, but I have no way of telling whether this
1658        is the right thing to do, as I do not use Windows. No doubt I'll get told
1659        if it's wrong...
1660    
1661    
1662    Version 4.3 21-May-03
1663    ---------------------
1664    
1665    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1666       Makefile.
1667    
1668    2. Some refactoring to improve the quality of the code:
1669    
1670       (i)   The utf8_table... variables are now declared "const".
1671    
1672       (ii)  The code for \cx, which used the "case flipping" table to upper case
1673             lower case letters, now just substracts 32. This is ASCII-specific,
1674             but the whole concept of \cx is ASCII-specific, so it seems
1675             reasonable.
1676    
1677       (iii) PCRE was using its character types table to recognize decimal and
1678             hexadecimal digits in the pattern. This is silly, because it handles
1679             only 0-9, a-f, and A-F, but the character types table is locale-
1680             specific, which means strange things might happen. A private
1681             table is now used for this - though it costs 256 bytes, a table is
1682             much faster than multiple explicit tests. Of course, the standard
1683             character types table is still used for matching digits in subject
1684             strings against \d.
1685    
1686       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1687             ending in _t are). So I've renamed it as ESC_tee.
1688    
1689    3. The first argument for regexec() in the POSIX wrapper should have been
1690       defined as "const".
1691    
1692    4. Changed pcretest to use malloc() for its buffers so that they can be
1693       Electric Fenced for debugging.
1694    
1695    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1696       to read one or more bytes before the start of the subject string. Often this
1697       had no effect on PCRE's behaviour, but in some circumstances it could
1698       provoke a segmentation fault.
1699    
1700    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1701       to try to read one or more bytes before the start of the subject string.
1702    
1703    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1704       UTF-8 support could misbehave in various ways if the subject string
1705       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1706       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1707       back over UTF-8 characters.)
1708    
1709    
1710    Version 4.2 14-Apr-03
1711    ---------------------
1712    
1713    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1714    
1715    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1716         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1717         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1718         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1719         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1720           and BUILD_EXEEXT
1721         Note: automatic setting of the BUILD variables is not yet working
1722         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1723           compile-time but not at link-time
1724         [LINK]: use for linking executables only
1725         make different versions for Windows and non-Windows
1726         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1727           libraries
1728         [LINK_FOR_BUILD]: new variable
1729         [OBJEXT]: use throughout
1730         [EXEEXT]: use throughout
1731         <winshared>: new target
1732         <wininstall>: new target
1733         <dftables.o>: use native compiler
1734         <dftables>: use native linker
1735         <install>: handle Windows platform correctly
1736         <clean>: ditto
1737         <check>: ditto
1738         copy DLL to top builddir before testing
1739    
1740       As part of these changes, -no-undefined was removed again. This was reported
1741       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1742       in any case.
1743    
1744    3. Some tidies to get rid of compiler warnings:
1745    
1746       . In the match_data structure, match_limit was an unsigned long int, whereas
1747         match_call_count was an int. I've made them both unsigned long ints.
1748    
1749       . In pcretest the fact that a const uschar * doesn't automatically cast to
1750         a void * provoked a warning.
1751    
1752       . Turning on some more compiler warnings threw up some "shadow" variables
1753         and a few more missing casts.
1754    
1755    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1756       option, a class that contained a single character with a value between 128
1757       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1758    
1759    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1760       option, a class that contained several characters, but with at least one
1761       whose value was between 128 and 255 caused PCRE to crash.
1762    
1763    
1764    Version 4.1 12-Mar-03
1765    ---------------------
1766    
1767    1. Compiling with gcc -pedantic found a couple of places where casts were
1768    needed, and a string in dftables.c that was longer than standard compilers are
1769    required to support.
1770    
1771    2. Compiling with Sun's compiler found a few more places where the code could
1772    be tidied up in order to avoid warnings.
1773    
1774    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1775    first of these names is deprecated in the latest Autoconf in favour of the name
1776    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1777    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1778    analogy I have changed it to CFLAGS_FOR_BUILD.
1779    
1780    4. Added -no-undefined to the linking command in the Makefile, because this is
1781    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1782    linking step for the pcreposix library.
1783    
1784    5. PCRE was failing to diagnose the case of two named groups with the same
1785    name.
1786    
1787    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1788    literal character that is needed in the subject for a match, and scans along to
1789    ensure that it is present before embarking on the full matching process. This
1790    saves time in cases of nested unlimited repeats that are never going to match.
1791    Problem: the scan can take a lot of time if the subject is very long (e.g.
1792    megabytes), thus penalizing straightforward matches. It is now done only if the
1793    amount of subject to be scanned is less than 1000 bytes.
1794    
1795    7. A lesser problem with the same optimization is that it was recording the
1796    first character of an anchored pattern as "needed", thus provoking a search
1797    right along the subject, even when the first match of the pattern was going to
1798    fail. The "needed" character is now not set for anchored patterns, unless it
1799    follows something in the pattern that is of non-fixed length. Thus, it still
1800    fulfils its original purpose of finding quick non-matches in cases of nested
1801    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1802    
1803    
1804    Version 4.0 17-Feb-03
1805    ---------------------
1806    
1807    1. If a comment in an extended regex that started immediately after a meta-item
1808    extended to the end of string, PCRE compiled incorrect data. This could lead to
1809    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1810    
1811    2. Moved to autoconf 2.53 and libtool 1.4.2.
1812    
1813    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1814    the special perltest8 script is no longer needed - all the tests can be run
1815    from a single perltest script.
1816    
1817    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1818    by \s. It has now been removed in PCRE. This means it isn't recognized as
1819    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
1820    class [:space:] *does* include VT, thereby creating a mess.
1821    
1822    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
1823    space and tab.
1824    
1825    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
1826    its new features into the main test script, reducing the number of scripts.
1827    
1828    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
1829    were backward compatible, and made the (?i) apply to the whole pattern, as if
1830    /i were given. Now it behaves more logically, and applies the option setting
1831    only to what follows. PCRE has been changed to follow suit. However, if it
1832    finds options settings right at the start of the pattern, it extracts them into
1833    the global options, as before. Thus, they show up in the info data.
1834    
1835    8. Added support for the \Q...\E escape sequence. Characters in between are
1836    treated as literals. This is slightly different from Perl in that $ and @ are
1837    also handled as literals inside the quotes. In Perl, they will cause variable
1838    interpolation. Note the following examples:
1839    
1840        Pattern            PCRE matches      Perl matches
1841    
1842        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
1843        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
1844        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
1845    
1846    For compatibility with Perl, \Q...\E sequences are recognized inside character
1847    classes as well as outside them.
1848    
1849    9. Re-organized 3 code statements in pcretest to avoid "overflow in
1850    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
1851    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
1852    signed/unsigned warnings.
1853    
1854    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
1855    option for pcretest, so I've replaced it by a simple function that does just
1856    that job.
1857    
1858    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
1859    "pcregrep -".
1860    
1861    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
1862    Java package. This provides some syntactic sugar for simple cases of what my
1863    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
1864    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
1865    item, you can use this simplified notation. Note that only makes sense with
1866    greedy quantifiers. Consequently, the use of the possessive quantifier forces
1867    greediness, whatever the setting of the PCRE_UNGREEDY option.
1868    
1869    13. A change of greediness default within a pattern was not taking effect at
1870    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
1871    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
1872    was abstracted outside.
1873    
1874    14. PCRE now supports the \G assertion. It is true when the current matching
1875    position is at the start point of the match. This differs from \A when the
1876    starting offset is non-zero. Used with the /g option of pcretest (or similar
1877    code), it works in the same way as it does for Perl's /g option. If all
1878    alternatives of a regex begin with \G, the expression is anchored to the start
1879    match position, and the "anchored" flag is set in the compiled expression.
1880    
1881    15. Some bugs concerning the handling of certain option changes within patterns
1882    have been fixed. These applied to options other than (?ims). For example,
1883    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
1884    been the other way round. Some of this was related to change 7 above.
1885    
1886    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
1887    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
1888    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
1889    POSIX classes only within a class (e.g. /[[:alpha:]]/).
1890    
1891    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
1892    mode. Unlike ".", it always matches newline, whatever the setting of
1893    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
1894    assertions. Perl allows it, but it doesn't (in general) work because it can't
1895    calculate the length of the lookbehind. At least, that's the case for Perl
1896    5.8.0 - I've been told they are going to document that it doesn't work in
1897    future.
1898    
1899    18. Added an error diagnosis for escapes that PCRE does not support: these are
1900    \L, \l, \N, \P, \p, \U, \u, and \X.
1901    
1902    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
1903    reading past the end of the pattern in cases such as /[abcd/.
1904    
1905    20. PCRE was getting more memory than necessary for patterns with classes that
1906    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
1907    
1908    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
1909    compiling PCRE for use with Virtual Pascal.
1910    
1911    22. Small fix to the Makefile to make it work properly if the build is done
1912    outside the source tree.
1913    
1914    23. Added a new extension: a condition to go with recursion. If a conditional
1915    subpattern starts with (?(R) the "true" branch is used if recursion has
1916    happened, whereas the "false" branch is used only at the top level.
1917    
1918    24. When there was a very long string of literal characters (over 255 bytes
1919    without UTF support, over 250 bytes with UTF support), the computation of how
1920    much memory was required could be incorrect, leading to segfaults or other
1921    strange effects.
1922    
1923    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
1924    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
1925    there was a subsequent back reference to those brackets. This meant that, for
1926    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
1927    possible to check for precisely this case. All we can do is abandon the
1928    optimization if .* occurs inside capturing brackets when there are any back
1929    references whatsoever. (See below for a better fix that came later.)
1930    
1931    26. The handling of the optimization for finding the first character of a
1932    non-anchored pattern, and for finding a character that is required later in the
1933    match were failing in some cases. This didn't break the matching; it just
1934    failed to optimize when it could. The way this is done has been re-implemented.
1935    
1936    27. Fixed typo in error message for invalid (?R item (it said "(?p").
1937    
1938    28. Added a new feature that provides some of the functionality that Perl
1939    provides with (?{...}). The facility is termed a "callout". The way it is done
1940    in PCRE is for the caller to provide an optional function, by setting
1941    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
1942    global variable. By default it is unset, which disables all calling out. To get
1943    the function called, the regex must include (?C) at appropriate points. This
1944    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
1945    This provides a means of identifying different callout points. When PCRE
1946    reaches such a point in the regex, if pcre_callout has been set, the external
1947    function is called. It is provided with data in a structure called
1948    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
1949    matching continues; if it returns a non-zero value, the match at the current
1950    point fails. However, backtracking will occur if possible. [This was changed
1951    later and other features added - see item 49 below.]
1952    
1953    29. pcretest is upgraded to test the callout functionality. It provides a
1954    callout function that displays information. By default, it shows the start of
1955    the match and the current position in the text. There are some new data escapes
1956    to vary what happens:
1957    
1958        \C+         in addition, show current contents of captured substrings
1959        \C-         do not supply a callout function
1960        \C!n        return 1 when callout number n is reached
1961        \C!n!m      return 1 when callout number n is reached for the mth time
1962    
1963    30. If pcregrep was called with the -l option and just a single file name, it
1964    output "<stdin>" if a match was found, instead of the file name.
1965    
1966    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
1967    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
1968    pcre_exec(). This saves a malloc/free per call. The default value of
1969    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
1970    when configuring.
1971    
1972    32. The default maximum size of a compiled pattern is 64K. There have been a
1973    few cases of people hitting this limit. The code now uses macros to handle the
1974    storing of links as offsets within the compiled pattern. It defaults to 2-byte
1975    links, but this can be changed to 3 or 4 bytes by --with-link-size when
1976    configuring. Tests 2 and 5 work only with 2-byte links because they output
1977    debugging information about compiled patterns.
1978    
1979    33. Internal code re-arrangements:
1980    
1981    (a) Moved the debugging function for printing out a compiled regex into
1982        its own source file (printint.c) and used #include to pull it into
1983        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
1984        separate copies.
1985    
1986    (b) Defined the list of op-code names for debugging as a macro in
1987        internal.h so that it is next to the definition of the opcodes.
1988    
1989    (c) Defined a table of op-code lengths for simpler skipping along compiled
1990        code. This is again a macro in internal.h so that it is next to the
1991        definition of the opcodes.
1992    
1993    34. Added support for recursive calls to individual subpatterns, along the
1994    lines of Robin Houston's patch (but implemented somewhat differently).
1995    
1996    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
1997    allow it to read and process whole directories in Win32. This code was
1998    contributed by Lionel Fourquaux; it has not been tested by me.
1999    
2000    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2001    used to name a group. Names consist of alphanumerics and underscores, and must
2002    be unique. Back references use the syntax (?P=name) and recursive calls use
2003    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2004    numbers. The function pcre_fullinfo() can be used after compilation to extract
2005    a name/number map. There are three relevant calls:
2006    
2007      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2008      PCRE_INFO_NAMECOUNT            yields the number of entries
2009      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2010    
2011    The map is a vector of fixed-size entries. The size of each entry depends on
2012    the length of the longest name used. The first two bytes of each entry are the
2013    group number, most significant byte first. There follows the corresponding
2014    name, zero terminated. The names are in alphabetical order.
2015    
2016    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2017    case instead of 255. Making it the same both with and without UTF-8 support
2018    means that the same test output works with both.
2019    
2020    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2021    calling malloc() with a zero argument.
2022    
2023    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2024    optimization. I've improved things by keeping a bitmap of backreferences with
2025    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2026    fact referenced, the optimization can be applied. It is unlikely that a
2027    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2028    the match to follow \n) will appear inside brackets with a number greater than
2029    31, but if it does, any back reference > 31 suppresses the optimization.
2030    
2031    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2032    of disabling numbered capturing parentheses. Any opening parenthesis that is
2033    not followed by ? behaves as if it were followed by ?: but named parentheses
2034    can still be used for capturing (and they will acquire numbers in the usual
2035    way).
2036    
2037    41. Redesigned the return codes from the match() function into yes/no/error so
2038    that errors can be passed back from deep inside the nested calls. A malloc
2039    failure while inside a recursive subpattern call now causes the
2040    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2041    
2042    42. It is now possible to set a limit on the number of times the match()
2043    function is called in a call to pcre_exec(). This facility makes it possible to
2044    limit the amount of recursion and backtracking, though not in a directly
2045    obvious way, because the match() function is used in a number of different
2046    circumstances. The count starts from zero for each position in the subject
2047    string (for non-anchored patterns). The default limit is, for compatibility, a
2048    large number, namely 10 000 000. You can change this in two ways:
2049    
2050    (a) When configuring PCRE before making, you can use --with-match-limit=n
2051        to set a default value for the compiled library.
2052    
2053    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2054        a different value is set. See 45 below.
2055    
2056    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2057    
2058    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2059    of things that can be changed at compile time. The first argument specifies
2060    what is wanted and the second points to where the information is to be placed.
2061    The current list of available information is:
2062    
2063      PCRE_CONFIG_UTF8
2064    
2065    The output is an integer that is set to one if UTF-8 support is available;
2066    otherwise it is set to zero.
2067    
2068      PCRE_CONFIG_NEWLINE
2069    
2070    The output is an integer that it set to the value of the code that is used for
2071    newline. It is either LF (10) or CR (13).
2072    
2073      PCRE_CONFIG_LINK_SIZE
2074    
2075    The output is an integer that contains the number of bytes used for internal
2076    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2077    
2078      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2079    
2080    The output is an integer that contains the threshold above which the POSIX
2081    interface uses malloc() for output vectors. See item 31 above.
2082    
2083      PCRE_CONFIG_MATCH_LIMIT
2084    
2085    The output is an unsigned integer that contains the default limit of the number
2086    of match() calls in a pcre_exec() execution. See 42 above.
2087    
2088    44. pcretest has been upgraded by the addition of the -C option. This causes it
2089    to extract all the available output from the new pcre_config() function, and to
2090    output it. The program then exits immediately.
2091    
2092    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2093    order to support additional features. One way would have been to define
2094    pcre_exec2() (for example) with extra arguments, but this would not have been
2095    extensible, and would also have required all calls to the original function to
2096    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2097    is used for passing in "extra" data from pcre_study().
2098    
2099    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2100    contains the following fields:
2101    
2102      flags         a bitmap indicating which of the following fields are set
2103      study_data    opaque data from pcre_study()
2104      match_limit   a way of specifying a limit on match() calls for a specific
2105                      call to pcre_exec()
2106      callout_data  data for callouts (see 49 below)
2107    
2108    The flag bits are also defined in pcre.h, and are
2109    
2110      PCRE_EXTRA_STUDY_DATA
2111      PCRE_EXTRA_MATCH_LIMIT
2112      PCRE_EXTRA_CALLOUT_DATA
2113    
2114    The pcre_study() function now returns one of these new pcre_extra blocks, with
2115    the actual study data pointed to by the study_data field, and the
2116    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2117    before. That is, this change is entirely upwards-compatible and requires no
2118    change to existing code.
2119    
2120    If you want to pass in additional data to pcre_exec(), you can either place it
2121    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2122    block.
2123    
2124    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2125    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2126    times with different match limits, until it finds the minimum value needed for
2127    pcre_exec() to complete. The value is then output. This can be instructive; for
2128    most simple matches the number is quite small, but for pathological cases it
2129    gets very large very quickly.
2130    
2131    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2132    returns the size of the data block pointed to by the study_data field in a
2133    pcre_extra block, that is, the value that was passed as the argument to
2134    pcre_malloc() when PCRE was getting memory in which to place the information
2135    created by pcre_study(). The fourth argument should point to a size_t variable.
2136    pcretest has been extended so that this information is shown after a successful
2137    pcre_study() call when information about the compiled regex is being displayed.
2138    
2139    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2140    because what follows is always an absolute path. (Later: it turns out that this
2141    is more than cosmetic for MinGW, because it doesn't like empty path
2142    components.)
2143    
2144    49. Some changes have been made to the callout feature (see 28 above):
2145    
2146    (i)  A callout function now has three choices for what it returns:
2147    
2148           0  =>  success, carry on matching
2149         > 0  =>  failure at this point, but backtrack if possible
2150         < 0  =>  serious error, return this value from pcre_exec()
2151    
2152         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2153         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2154         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2155         use by callout functions. It will never be used by PCRE itself.
2156    
2157    (ii) The pcre_extra structure (see 45 above) has a void * field called
2158         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2159         pcre_callout_block structure has a field of the same name. The contents of
2160         the field passed in the pcre_extra structure are passed to the callout
2161         function in the corresponding field in the callout block. This makes it
2162         easier to use the same callout-containing regex from multiple threads. For
2163         testing, the pcretest program has a new data escape
2164    
2165           \C*n        pass the number n (may be negative) as callout_data
2166    
2167         If the callout function in pcretest receives a non-zero value as
2168         callout_data, it returns that value.
2169    
2170    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2171    there were some redundant $(CFLAGS) in commands that are now specified as
2172    $(LINK), which already includes $(CFLAGS).
2173    
2174    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2175    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2176    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2177    one-byte characters throughout. Note that case-insensitive matching applies
2178    only to characters whose values are less than 256. PCRE doesn't support the
2179    notion of cases for higher-valued characters.
2180    
2181    (i)   A character class whose characters are all within 0-255 is handled as
2182          a bit map, and the map is inverted for negative classes. Previously, a
2183          character > 255 always failed to match such a class; however it should
2184          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2185    
2186    (ii)  A negated character class with a single character < 255 is coded as
2187          "not this character" (OP_NOT). This wasn't working properly when the test
2188          character was multibyte, either singly or repeated.
2189    
2190    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2191          mode, for example: \x{100}{2,3}.
2192    
2193    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2194          singly or repeated) now correctly test multibyte characters. However,
2195          PCRE doesn't recognize any characters with values greater than 255 as
2196          digits, spaces, or word characters. Such characters always match \D, \S,
2197          and \W, and never match \d, \s, or \w.
2198    
2199    (v)   Classes may now contain characters and character ranges with values
2200          greater than 255. For example: [ab\x{100}-\x{400}].
2201    
2202    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2203          PCRE in UTF-8 mode.
2204    
2205    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2206    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2207    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2208    value.)
2209    
2210    53. The single man page has become too large. I have therefore split it up into
2211    a number of separate man pages. These also give rise to individual HTML pages;
2212    these are now put in a separate directory, and there is an index.html page that
2213    lists them all. Some hyperlinking between the pages has been installed.
2214    
2215    54. Added convenience functions for handling named capturing parentheses.
2216    
2217    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2218    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2219    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2220    are faulted.
2221    
2222    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2223    calling configure. These values are used when compiling the dftables.c program
2224    which is run to generate the source of the default character tables. They
2225    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2226    you will need to set these values.
2227    
2228    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2229    
2230    
2231    Version 3.9 02-Jan-02
2232    ---------------------
2233    
2234    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2235    
2236    2. If --disable-static was given, the building process failed when trying to
2237    build pcretest and pcregrep. (For some reason it was using libtool to compile
2238    them, which is not right, as they aren't part of the library.)
2239    
2240    
2241    Version 3.8 18-Dec-01
2242    ---------------------
2243    
2244    1. The experimental UTF-8 code was completely screwed up. It was packing the
2245    bytes in the wrong order. How dumb can you get?
2246    
2247    
2248    Version 3.7 29-Oct-01
2249    ---------------------
2250    
2251    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2252    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2253    this didn't happen under Solaris 8, where I normally test things.
2254    
2255    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2256    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2257    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2258    this fix an hour or so after the initial 3.7 release.)
2259    
2260    
2261    Version 3.6 23-Oct-01
2262    ---------------------
2263    
2264    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2265    offsets passed as NULL with zero offset count.
2266    
2267    2. The config.guess and config.sub files had not been updated when I moved to
2268    the latest autoconf.
2269    
2270    
2271    Version 3.5 15-Aug-01
2272    ---------------------
2273    
2274    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2275    had been forgotten.
2276    
2277    2. By using declared but undefined structures, we can avoid using "void"
2278    definitions in pcre.h while keeping the internal definitions of the structures
2279    private.
2280    
2281    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2282    user point of view, this means that both static and shared libraries are built
2283    by default, but this can be individually controlled. More of the work of
2284    handling this static/shared cases is now inside libtool instead of PCRE's make
2285    file.
2286    
2287    4. The pcretest utility is now installed along with pcregrep because it is
2288    useful for users (to test regexs) and by doing this, it automatically gets
2289    relinked by libtool. The documentation has been turned into a man page, so
2290    there are now .1, .txt, and .html versions in /doc.
2291    
2292    5. Upgrades to pcregrep:
2293       (i)   Added long-form option names like gnu grep.
2294       (ii)  Added --help to list all options with an explanatory phrase.
2295       (iii) Added -r, --recursive to recurse into sub-directories.
2296       (iv)  Added -f, --file to read patterns from a file.
2297    
2298    6. pcre_exec() was referring to its "code" argument before testing that
2299    argument for NULL (and giving an error if it was NULL).
2300    
2301    7. Upgraded Makefile.in to allow for compiling in a different directory from
2302    the source directory.
2303    
2304    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2305    options bits, the pointer it was passed was to an int instead of to an unsigned
2306    long int. This mattered only on 64-bit systems.
2307    
2308    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2309    generated) instead of pcre.in, which it its source. Also made the same change
2310    in several of the .c files.
2311    
2312    10. A new release of gcc defines printf() as a macro, which broke pcretest
2313    because it had an ifdef in the middle of a string argument for printf(). Fixed
2314    by using separate calls to printf().
2315    
2316    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2317    script, to force use of CR or LF instead of \n in the source. On non-Unix
2318    systems, the value can be set in config.h.
2319    
2320    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2321    absolute limit. Changed the text of the error message to make this clear, and
2322    likewise updated the man page.
2323    
2324    13. The limit of 99 on the number of capturing subpatterns has been removed.
2325    The new limit is 65535, which I hope will not be a "real" limit.
2326    
2327    
2328    Version 3.4 22-Aug-00
2329    ---------------------
2330    
2331    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2332    
2333    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2334    
2335    
2336    Version 3.3 01-Aug-00
2337    ---------------------
2338    
2339    1. If an octal character was given, but the value was greater than \377, it
2340    was not getting masked to the least significant bits, as documented. This could
2341    lead to crashes in some systems.
2342    
2343    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2344    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2345    
2346    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2347    These just pass their arguments on to (pcre_free)(), but they are provided
2348    because some uses of PCRE bind it to non-C systems that can call its functions,
2349    but cannot call free() or pcre_free() directly.
2350    
2351    4. Add "make test" as a synonym for "make check". Corrected some comments in
2352    the Makefile.
2353    
2354    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2355    Makefile.
2356    
2357    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2358    command called pgrep for grepping around the active processes.
2359    
2360    7. Added the beginnings of support for UTF-8 character strings.
2361    
2362    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2363    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2364    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2365    out for the ar command.)
2366    
2367    
2368    Version 3.2 12-May-00
2369    ---------------------
2370    
2371    This is purely a bug fixing release.
2372    
2373    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2374    of ZA. This was just one example of several cases that could provoke this bug,
2375    which was introduced by change 9 of version 2.00. The code for breaking
2376    infinite loops after an iteration that matches an empty string was't working
2377    correctly.
2378    
2379    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2380    when matched against abbab (for example). After matching an empty string, it
2381    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2382    caused it to match further down the string than it should.
2383    
2384    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2385    was there because it doesn't seem to be needed, and it causes trouble on some
2386    systems, as it is not a Standard C header. It has been removed.
2387    
2388    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2389    were reported on the Macintosh. The changes were from
2390    
2391      while ((c = *(++ptr)) != 0 && c != '\n');
2392    to
2393      while ((c = *(++ptr)) != 0 && c != '\n') ;
2394    
2395    Totally extraordinary, but if that's what it takes...
2396    
2397    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2398    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2399    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2400    assumes the way PCRE uses memmove() (always moving upwards).
2401    
2402    6. PCRE is being used in one environment where strchr() is not available. There
2403    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2404    faster code anyway.
2405    
2406    
2407    Version 3.1 09-Feb-00
2408    ---------------------
2409    
2410    The only change in this release is the fixing of some bugs in Makefile.in for
2411    the "install" target:
2412    
2413    (1) It was failing to install pcreposix.h.
2414    
2415    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2416    
2417    
2418    Version 3.0 01-Feb-00
2419    ---------------------
2420    
2421    1. Add support for the /+ modifier to perltest (to output $` like it does in
2422    pcretest).
2423    
2424    2. Add support for the /g modifier to perltest.
2425    
2426    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2427    matches null strings.
2428    
2429    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2430    pattern. Perl treats empty patterns specially - it reuses the most recent
2431    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2432    effect.
2433    
2434    5. The POSIX interface was broken in that it was just handing over the POSIX
2435    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2436    required a bigger vector, with some working space on the end. This means that
2437    the POSIX wrapper now has to get and free some memory, and copy the results.
2438    
2439    6. Added some simple autoconf support, placing the test data and the
2440    documentation in separate directories, re-organizing some of the
2441    information files, and making it build pcre-config (a GNU standard). Also added
2442    libtool support for building PCRE as a shared library, which is now the
2443    default.
2444    
2445    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2446    09 are not valid octal constants. Single digits will be used for minor values
2447    less than 10.
2448    
2449    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2450    existing programs that set these in the POSIX interface can use PCRE without
2451    modification.
2452    
2453    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2454    return all that pcre_info() returns, plus additional data. The pcre_info()
2455    function is retained for compatibility, but is considered to be obsolete.
2456    
2457    10. Added experimental recursion feature (?R) to handle one common case that
2458    Perl 5.6 will be able to do with (?p{...}).
2459    
2460    11. Added support for POSIX character classes like [:alpha:], which Perl is
2461    adopting.
2462    
2463    
2464    Version 2.08 31-Aug-99
2465    ----------------------
2466    
2467    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2468    trying to match at the startoffset position, but instead was moving forward to
2469    the next newline as if a previous match had failed.
2470    
2471    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2472    and could get into a loop if a null string was matched other than at the start
2473    of the subject.
2474    
2475    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2476    be distinguished at compile time, and for completeness also added PCRE_DATE.
2477    
2478    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2479    in GnuWin32 environments.
2480    
2481    
2482    Version 2.07 29-Jul-99
2483    ----------------------
2484    
2485    1. The documentation is now supplied in plain text form and HTML as well as in
2486    the form of man page sources.
2487    
2488    2. C++ compilers don't like assigning (void *) values to other pointer types.
2489    In particular this affects malloc(). Although there is no problem in Standard
2490    C, I've put in casts to keep C++ compilers happy.
2491    
2492    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2493    should be (const char *).
2494    
2495    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2496    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2497    However, I haven't made this a standard facility. The documentation doesn't
2498    mention it, and the Makefile doesn't support it.
2499    
2500    5. The Makefile now contains an "install" target, with editable destinations at
2501    the top of the file. The pcretest program is not installed.
2502    
2503    6. pgrep -V now gives the PCRE version number and date.
2504    
2505    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2506    causing the entire string to be ignored, instead of just the last character.
2507    
2508    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2509    non-matching string, it can take a very, very long time, even for strings of
2510    quite modest length, because of the nested recursion. PCRE now does better in
2511    some of these cases. It does this by remembering the last required literal
2512    character in the pattern, and pre-searching the subject to ensure it is present
2513    before running the real match. In other words, it applies a heuristic to detect
2514    some types of certain failure quickly, and in the above example, if presented
2515    with a string that has no trailing " it gives "no match" very quickly.
2516    
2517    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2518    other alternatives are tried instead.
2519    
2520    
2521    Version 2.06 09-Jun-99
2522    ----------------------
2523    
2524    1. Change pcretest's output for amount of store used to show just the code
2525    space, because the remainder (the data block) varies in size between 32-bit and
2526    64-bit systems.
2527    
2528    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2529    start matching at. This allows lookbehinds to work when searching for multiple
2530    occurrences in a string.
2531    
2532    3. Added additional options to pcretest for testing multiple occurrences:
2533    
2534       /+   outputs the rest of the string that follows a match
2535       /g   loops for multiple occurrences, using the new startoffset argument
2536       /G   loops for multiple occurrences by passing an incremented pointer
2537    
2538    4. PCRE wasn't doing the "first character" optimization for patterns starting
2539    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2540    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2541    the letter 'x'. On long subject strings, this gives a significant speed-up.
2542    
2543    
2544    Version 2.05 21-Apr-99
2545    ----------------------
2546    
2547    1. Changed the type of magic_number from int to long int so that it works
2548    properly on 16-bit systems.
2549    
2550    2. Fixed a bug which caused patterns starting with .* not to work correctly
2551    when the subject string contained newline characters. PCRE was assuming
2552    anchoring for such patterns in all cases, which is not correct because .* will
2553    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2554    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2555    must be retried after every newline in the subject.
2556    
2557    
2558    Version 2.04 18-Feb-99
2559    ----------------------
2560    
2561    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2562    computation of the store needed to hold the pattern was incorrect (too large).
2563    If such patterns were nested a few deep, this could multiply and become a real
2564    problem.
2565    
2566    2. Added /M option to pcretest to show the memory requirement of a specific
2567    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2568    
2569    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2570    compiled in such a way that the backtracking after subsequent failure was
2571    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2572    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2573    
2574    
2575    Version 2.03 02-Feb-99
2576    ----------------------
2577    
2578    1. Fixed typo and small mistake in man page.
2579    
2580    2. Added 4th condition (GPL supersedes if conflict) and created separate
2581    LICENCE file containing the conditions.
2582    
2583    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2584    Perl, that is the internal \ allows the delimiter to be included in the
2585    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2586    the final delimiter, add \ to the end of the pattern (to test the error).
2587    
2588    4. Added the convenience functions for extracting substrings after a successful
2589    match. Updated pcretest to make it able to test these functions.
2590    
2591    
2592    Version 2.02 14-Jan-99
2593    ----------------------
2594    
2595    1. Initialized the working variables associated with each extraction so that
2596    their saving and restoring doesn't refer to uninitialized store.
2597    
2598    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2599    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2600    fix the problem.
2601    
2602    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2603    calls, and wasn't printing the correct value for compiling calls. Increased the
2604    default value of LOOPREPEAT, and the number of significant figures in the
2605    times.
2606    
2607    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2608    
2609    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2610    a building problem on Windows NT with a FAT file system.
2611    
2612    
2613    Version 2.01 21-Oct-98
2614    ----------------------
2615    
2616    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2617    to character tables built by pcre_maketables() in the current locale. If NULL
2618    is passed, the default tables are used.
2619    
2620    
2621    Version 2.00 24-Sep-98
2622    ----------------------
2623    
2624    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2625    it any more.
2626    
2627    2. Allow quantification of (?>) groups, and make it work correctly.
2628    
2629    3. The first character computation wasn't working for (?>) groups.
2630    
2631    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2632    end of the subject) and add 5.005's \z, which really does match only at the
2633    very end of the subject.
2634    
2635    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2636    
2637    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
2638    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
2639    localized options. All options to pcre_study() were also removed.
2640    
2641    7. Add other new features from 5.005:
2642    
2643       $(?<=           positive lookbehind
2644       $(?<!           negative lookbehind
2645       (?imsx-imsx)    added the unsetting capability
2646                       such a setting is global if at outer level; local otherwise
2647       (?imsx-imsx:)   non-capturing groups with option setting
2648       (?(cond)re|re)  conditional pattern matching
2649    
2650       A backreference to itself in a repeated group matches the previous
2651       captured string.
2652    
2653    8. General tidying up of studying (both automatic and via "study")
2654    consequential on the addition of new assertions.
2655    
2656    9. As in 5.005, unlimited repeated groups that could match an empty substring
2657    are no longer faulted at compile time. Instead, the loop is forcibly broken at
2658    runtime if any iteration does actually match an empty substring.
2659    
2660    10. Include the RunTest script in the distribution.
2661    
2662    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
2663    discrepancies, some of which were old and were also with respect to 5.004. They
2664    have now been fixed.
2665    
2666    
2667    Version 1.09 28-Apr-98
2668    ----------------------
2669    
2670    1. A negated single character class followed by a quantifier with a minimum
2671    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
2672    program crashes, or just wrong answers. This did not apply to negated classes
2673    containing more than one character, or to minima other than one.
2674    
2675    
2676    Version 1.08 27-Mar-98
2677    ----------------------
2678    
2679    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
2680    
2681    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
2682    latter must appear before anything that relies on it in the pattern.
2683    
2684    
2685    Version 1.07 16-Feb-98
2686    ----------------------
2687    
2688    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
2689    repeat of a potentially empty string).
2690    
2691    
2692    Version 1.06 23-Jan-98
2693    ----------------------
2694    
2695    1. Added Markus Oberhumer's little patches for C++.
2696    
2697    2. Literal strings longer than 255 characters were broken.
2698    
2699    
2700    Version 1.05 23-Dec-97
2701    ----------------------
2702    
2703    1. Negated character classes containing more than one character were failing if
2704    PCRE_CASELESS was set at run time.
2705    
2706    
2707    Version 1.04 19-Dec-97
2708    ----------------------
2709    
2710    1. Corrected the man page, where some "const" qualifiers had been omitted.
2711    
2712    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
2713    input syntax.
2714    
2715    3. Fixed memory leak which occurred when a regex with back references was
2716    matched with an offsets vector that wasn't big enough. The temporary memory
2717    that is used in this case wasn't being freed if the match failed.
2718    
2719    4. Tidied pcretest to ensure it frees memory that it gets.
2720    
2721    5. Temporary memory was being obtained in the case where the passed offsets
2722    vector was exactly big enough.
2723    
2724    6. Corrected definition of offsetof() from change 5 below.
2725    
2726    7. I had screwed up change 6 below and broken the rules for the use of
2727    setjmp(). Now fixed.
2728    
2729    
2730    Version 1.03 18-Dec-97
2731    ----------------------
2732    
2733    1. A erroneous regex with a missing opening parenthesis was correctly
2734    diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
2735    on some systems.
2736    
2737    2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
2738    it was reported that one broken compiler failed on the former because "code" is
2739    also an independent variable.
2740    
2741    3. The erroneous regex a[]b caused an array overrun reference.
2742    
2743    4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
2744    fail on data ending with that character. (It was going on too far, and checking
2745    the next character, typically a binary zero.) This was specific to the
2746    optimized code for single-character negative classes.
2747    
2748    5. Added a contributed patch from the TIN world which does the following:
2749    
2750      + Add an undef for memmove, in case the the system defines a macro for it.
2751    
2752      + Add a definition of offsetof(), in case there isn't one. (I don't know
2753        the reason behind this - offsetof() is part of the ANSI standard - but
2754        it does no harm).
2755    
2756      + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
2757        most of the places where whitespace preceded '#'. I have given up and
2758        allowed the remaining 2 cases to be at the margin.
2759    
2760      + Rename some variables in pcre to eliminate shadowing. This seems very
2761        pedantic, but does no harm, of course.
2762    
2763    6. Moved the call to setjmp() into its own function, to get rid of warnings
2764    from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
2765    
2766    7. Constructs such as \d{8,} were compiling into the equivalent of
2767    \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
2768    outcome, but in this particular case used more store than had been allocated,
2769    which caused the bug to be discovered because it threw up an internal error.
2770    
2771    8. The debugging code in both pcre and pcretest for outputting the compiled
2772    form of a regex was going wrong in the case of back references followed by
2773    curly-bracketed repeats.
2774    
2775    
2776    Version 1.02 12-Dec-97
2777    ----------------------
2778    
2779    1. Typos in pcre.3 and comments in the source fixed.
2780    
2781    2. Applied a contributed patch to get rid of places where it used to remove
2782    'const' from variables, and fixed some signed/unsigned and uninitialized
2783    variable warnings.
2784    
2785    3. Added the "runtest" target to Makefile.
2786    
2787    4. Set default compiler flag to -O2 rather than just -O.
2788    
2789    
2790    Version 1.01 19-Nov-97
2791    ----------------------
2792    
2793    1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
2794    like /([ab]*)*/, that is, for classes with more than one character in them.
2795    
2796    2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
2797    as /((?>a*))*/ (a PCRE_EXTRA facility).
2798    
2799    
2800    Version 1.00 18-Nov-97
2801    ----------------------
2802    
2803    1. Added compile-time macros to support systems such as SunOS4 which don't have
2804    memmove() or strerror() but have other things that can be used instead.
2805    
2806    2. Arranged that "make clean" removes the executables.
2807    
2808    
2809  Version 0.99 27-Oct-97  Version 0.99 27-Oct-97
2810  ----------------------  ----------------------
2811    

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