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revision 31 by nigel, Sat Feb 24 21:38:57 2007 UTC revision 300 by ph10, Mon Jan 14 19:43:19 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.6 14-Jan-08
5    ---------------------
6    
7    1.  A class with a very large number of characters with codepoints greater
8        than 255 (in UTF-8 mode, of course), caused a buffer overflow.
9    
10    
11    Version 7.5 10-Jan-08
12    ---------------------
13    
14    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
15        values in parens when parsing an RE using the C++ wrapper."
16    
17    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
18        Characters greater than 255 were excluded from the class instead of being
19        included.
20    
21    3.  The same bug as (2) above applied to negated POSIX classes such as
22        [:^space:].
23    
24    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
25        defined or documented. It seems to have been a typo for PCRE_STATIC, so
26        I have changed it.
27    
28    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
29        first named subpattern) and a construct such as (?&a) would reference the
30        first named subpattern whose name started with "a" (in other words, the
31        length check was missing). Both these problems are fixed. "Subpattern name
32        expected" is now given for (?&) (a zero-length name), and this patch also
33        makes it give the same error for \k'' (previously it complained that that
34        was a reference to a non-existent subpattern).
35    
36    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
37        this is right because (?- can be followed by option settings as well as by
38        digits. I have, however, made the messages clearer.
39    
40    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
41        than the number used in the conditional) now cause a compile-time error.
42        This is actually not compatible with Perl, which accepts such patterns, but
43        treats the conditional as always being FALSE (as PCRE used to), but it
44        seems to me that giving a diagnostic is better.
45    
46    8.  Change "alphameric" to the more common word "alphanumeric" in comments
47        and messages.
48    
49    9.  Fix two occurrences of "backslash" in comments that should have been
50        "backspace".
51    
52    10. Remove two redundant lines of code that can never be obeyed (their function
53        was moved elsewhere).
54    
55    11. The program that makes PCRE's Unicode character property table had a bug
56        which caused it to generate incorrect table entries for sequences of
57        characters that have the same character type, but are in different scripts.
58        It amalgamated them into a single range, with the script of the first of
59        them. In other words, some characters were in the wrong script. There were
60        thirteen such cases, affecting characters in the following ranges:
61    
62          U+002b0 - U+002c1
63          U+0060c - U+0060d
64          U+0061e - U+00612
65          U+0064b - U+0065e
66          U+0074d - U+0076d
67          U+01800 - U+01805
68          U+01d00 - U+01d77
69          U+01d9b - U+01dbf
70          U+0200b - U+0200f
71          U+030fc - U+030fe
72          U+03260 - U+0327f
73          U+0fb46 - U+0fbb1
74          U+10450 - U+1049d
75    
76    12. The -o option (show only the matching part of a line) for pcregrep was not
77        compatible with GNU grep in that, if there was more than one match in a
78        line, it showed only the first of them. It now behaves in the same way as
79        GNU grep.
80    
81    13. If the -o and -v options were combined for pcregrep, it printed a blank
82        line for every non-matching line. GNU grep prints nothing, and pcregrep now
83        does the same. The return code can be used to tell if there were any
84        non-matching lines.
85    
86    14. Added --file-offsets and --line-offsets to pcregrep.
87    
88    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
89        infinitely looping recursion. The bug was that positive lookaheads were not
90        being skipped when checking for a possible empty match (negative lookaheads
91        and both kinds of lookbehind were skipped).
92    
93    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
94        inclusion of <windows.h> to before rather than after the definition of
95        INVALID_FILE_ATTRIBUTES (patch from David Byron).
96    
97    17. Specifying a possessive quantifier with a specific limit for a Unicode
98        character property caused pcre_compile() to compile bad code, which led at
99        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
100        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
101        caused the error; without that there was no problem.
102    
103    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
104    
105    19. Added --enable-pcretest-libreadline.
106    
107    20. In pcrecpp.cc, the variable 'count' was incremented twice in
108        RE::GlobalReplace(). As a result, the number of replacements returned was
109        double what it should be. I removed one of the increments, but Craig sent a
110        later patch that removed the other one (the right fix) and added unit tests
111        that check the return values (which was not done before).
112    
113    21. Several CMake things:
114    
115        (1) Arranged that, when cmake is used on Unix, the libraries end up with
116            the names libpcre and libpcreposix, not just pcre and pcreposix.
117    
118        (2) The above change means that pcretest and pcregrep are now correctly
119            linked with the newly-built libraries, not previously installed ones.
120    
121        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
122    
123    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
124        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
125        UTF-8 newline character). The key issue is that the pattern starts .*;
126        this means that the match must be either at the beginning, or after a
127        newline. The bug was in the code for advancing after a failed match and
128        checking that the new position followed a newline. It was not taking
129        account of UTF-8 characters correctly.
130    
131    23. PCRE was behaving differently from Perl in the way it recognized POSIX
132        character classes. PCRE was not treating the sequence [:...:] as a
133        character class unless the ... were all letters. Perl, however, seems to
134        allow any characters between [: and :], though of course it rejects as
135        unknown any "names" that contain non-letters, because all the known class
136        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
137        for example, whereas PCRE did not - it did not recognize a POSIX character
138        class. This seemed a bit dangerous, so the code has been changed to be
139        closer to Perl. The behaviour is not identical to Perl, because PCRE will
140        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
141        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
142        Perl does, and where it didn't before.
143    
144    24. Rewrite so as to remove the single use of %n from pcregrep because in some
145        Windows environments %n is disabled by default.
146    
147    
148    Version 7.4 21-Sep-07
149    ---------------------
150    
151    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
152        means that a class such as [\s] counted as "explicit reference to CR or
153        LF". That isn't really right - the whole point of the change was to try to
154        help when there was an actual mention of one of the two characters. So now
155        the change happens only if \r or \n (or a literal CR or LF) character is
156        encountered.
157    
158    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
159        of both had grown to the point where there were only 3 bits left.
160        Fortunately, there was spare space in the data structure, and so I have
161        moved the internal flags into a new 16-bit field to free up more option
162        bits.
163    
164    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
165        but did not set the internal JCHANGED flag - either of these is enough to
166        control the way the "get" function works - but the PCRE_INFO_JCHANGED
167        facility is supposed to tell if (?J) was ever used, so now (?J) at the
168        start sets both bits.
169    
170    4.  Added options (at build time, compile time, exec time) to change \R from
171        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
172    
173    5.  doc/pcresyntax.html was missing from the distribution.
174    
175    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
176        compatibility, even though it is no longer used.
177    
178    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
179        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
180        windows.h file is present (where different names are used). [This was
181        reversed later after testing - see 16 below.]
182    
183    8.  Changed all #include <config.h> to #include "config.h". There were also
184        some further <pcre.h> cases that I changed to "pcre.h".
185    
186    9.  When pcregrep was used with the --colour option, it missed the line ending
187        sequence off the lines that it output.
188    
189    10. It was pointed out to me that arrays of string pointers cause lots of
190        relocations when a shared library is dynamically loaded. A technique of
191        using a single long string with a table of offsets can drastically reduce
192        these. I have refactored PCRE in four places to do this. The result is
193        dramatic:
194    
195          Originally:                          290
196          After changing UCP table:            187
197          After changing error message table:   43
198          After changing table of "verbs"       36
199          After changing table of Posix names   22
200    
201        Thanks to the folks working on Gregex for glib for this insight.
202    
203    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
204        unicode-properties was also set.
205    
206    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
207    
208    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
209        checked only for CRLF.
210    
211    14. Added casts to pcretest.c to avoid compiler warnings.
212    
213    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
214    
215    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
216        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
217        entirely. This removes changes made in 7 above.
218    
219    17. The CMake files have been updated, and there is now more information about
220        building with CMake in the NON-UNIX-USE document.
221    
222    
223    Version 7.3 28-Aug-07
224    ---------------------
225    
226     1. In the rejigging of the build system that eventually resulted in 7.1, the
227        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
228        brackets there is not right, since it causes compilers to look for an
229        installed pcre.h, not the version that is in the source that is being
230        compiled (which of course may be different). I have changed it back to:
231    
232          #include "pcre.h"
233    
234        I have a vague recollection that the change was concerned with compiling in
235        different directories, but in the new build system, that is taken care of
236        by the VPATH setting the Makefile.
237    
238     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
239        when the subject happened to end in the byte 0x85 (e.g. if the last
240        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
241        characters but of course it shouldn't be taken as a newline when it is part
242        of another character. The bug was that, for an unlimited repeat of . in
243        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
244        characters when looking for a newline.
245    
246     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
247    
248     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
249        in debug output.
250    
251     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
252        long printing in the pcrecpp unittest when running under MinGW.
253    
254     6. ESC_K was left out of the EBCDIC table.
255    
256     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
257        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
258        limit also applies to "virtual nesting" when a pattern is recursive, and in
259        this case 1000 isn't so big. I have been able to remove this limit at the
260        expense of backing off one optimization in certain circumstances. Normally,
261        when pcre_exec() would call its internal match() function recursively and
262        immediately return the result unconditionally, it uses a "tail recursion"
263        feature to save stack. However, when a subpattern that can match an empty
264        string has an unlimited repetition quantifier, it no longer makes this
265        optimization. That gives it a stack frame in which to save the data for
266        checking that an empty string has been matched. Previously this was taken
267        from the 1000-entry workspace that had been reserved. So now there is no
268        explicit limit, but more stack is used.
269    
270     8. Applied Daniel's patches to solve problems with the import/export magic
271        syntax that is required for Windows, and which was going wrong for the
272        pcreposix and pcrecpp parts of the library. These were overlooked when this
273        problem was solved for the main library.
274    
275     9. There were some crude static tests to avoid integer overflow when computing
276        the size of patterns that contain repeated groups with explicit upper
277        limits. As the maximum quantifier is 65535, the maximum group length was
278        set at 30,000 so that the product of these two numbers did not overflow a
279        32-bit integer. However, it turns out that people want to use groups that
280        are longer than 30,000 bytes (though not repeat them that many times).
281        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
282        made it possible to implement the integer overflow checks in a much more
283        dynamic way, which I have now done. The artificial limitation on group
284        length has been removed - we now have only the limit on the total length of
285        the compiled pattern, which depends on the LINK_SIZE setting.
286    
287    10. Fixed a bug in the documentation for get/copy named substring when
288        duplicate names are permitted. If none of the named substrings are set, the
289        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
290        empty string.
291    
292    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
293        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
294        because the ] is interpreted as the first data character and the
295        terminating ] is not found. PCRE has been made compatible with Perl in this
296        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
297        cause memory overwriting.
298    
299    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
300        string has been matched (to stop an infinite loop). It was not recognizing
301        a conditional subpattern that could match an empty string if that
302        subpattern was within another subpattern. For example, it looped when
303        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
304        condition was not nested. This bug has been fixed.
305    
306    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
307        past the start of the subject in the presence of bytes with the top bit
308        set, for example "\x8aBCD".
309    
310    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
311        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
312    
313    14. Optimized (?!) to (*FAIL).
314    
315    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
316        This restricts code points to be within the range 0 to 0x10FFFF, excluding
317        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
318        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
319        does: it's just the validity check that is more restrictive.
320    
321    16. Inserted checks for integer overflows during escape sequence (backslash)
322        processing, and also fixed erroneous offset values for syntax errors during
323        backslash processing.
324    
325    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
326        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
327    
328    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
329        caused an overrun.
330    
331    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
332        something other than just ASCII characters) inside a group that had an
333        unlimited repeat caused a loop at compile time (while checking to see
334        whether the group could match an empty string).
335    
336    20. Debugging a pattern containing \p or \P could cause a crash. For example,
337        [\P{Any}] did so. (Error in the code for printing property names.)
338    
339    21. An orphan \E inside a character class could cause a crash.
340    
341    22. A repeated capturing bracket such as (A)? could cause a wild memory
342        reference during compilation.
343    
344    23. There are several functions in pcre_compile() that scan along a compiled
345        expression for various reasons (e.g. to see if it's fixed length for look
346        behind). There were bugs in these functions when a repeated \p or \P was
347        present in the pattern. These operators have additional parameters compared
348        with \d, etc, and these were not being taken into account when moving along
349        the compiled data. Specifically:
350    
351        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
352            length.
353    
354        (b) An item such as \pL+ within a repeated group could cause crashes or
355            loops.
356    
357        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
358            "reference to non-existent subpattern" error.
359    
360        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
361    
362    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
363        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
364    
365    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
366    
367    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
368        character were causing crashes (broken optimization).
369    
370    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
371        \p or \P) caused a compile-time loop.
372    
373    28. More problems have arisen in unanchored patterns when CRLF is a valid line
374        break. For example, the unstudied pattern [\r\n]A does not match the string
375        "\r\nA" because change 7.0/46 below moves the current point on by two
376        characters after failing to match at the start. However, the pattern \nA
377        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
378        the same is true. There doesn't seem any very clean way out of this, but
379        what I have chosen to do makes the common cases work: PCRE now takes note
380        of whether there can be an explicit match for \r or \n anywhere in the
381        pattern, and if so, 7.0/46 no longer applies. As part of this change,
382        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
383        pattern has explicit CR or LF references.
384    
385    29. Added (*CR) etc for changing newline setting at start of pattern.
386    
387    
388    Version 7.2 19-Jun-07
389    ---------------------
390    
391     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
392        which is apparently normally available under Windows.
393    
394     2. Re-jig the pcregrep tests with different newline settings in an attempt
395        to make them independent of the local environment's newline setting.
396    
397     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
398    
399     4. Some of the "internals" tests were previously cut out when the link size
400        was not 2, because the output contained actual offsets. The recent new
401        "Z" feature of pcretest means that these can be cut out, making the tests
402        usable with all link sizes.
403    
404     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
405        stack recursion. This gives a massive performance boost under BSD, but just
406        a small improvement under Linux. However, it saves one field in the frame
407        in all cases.
408    
409     6. Added more features from the forthcoming Perl 5.10:
410    
411        (a) (?-n) (where n is a string of digits) is a relative subroutine or
412            recursion call. It refers to the nth most recently opened parentheses.
413    
414        (b) (?+n) is also a relative subroutine call; it refers to the nth next
415            to be opened parentheses.
416    
417        (c) Conditions that refer to capturing parentheses can be specified
418            relatively, for example, (?(-2)... or (?(+3)...
419    
420        (d) \K resets the start of the current match so that everything before
421            is not part of it.
422    
423        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
424    
425        (f) \g{name} is another synonym - part of Perl 5.10's unification of
426            reference syntax.
427    
428        (g) (?| introduces a group in which the numbering of parentheses in each
429            alternative starts with the same number.
430    
431        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
432    
433     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
434        PCRE_INFO_JCHANGED.
435    
436     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
437        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
438        for detecting groups that can match an empty string.
439    
440     9. A pattern with a very large number of alternatives (more than several
441        hundred) was running out of internal workspace during the pre-compile
442        phase, where pcre_compile() figures out how much memory will be needed. A
443        bit of new cunning has reduced the workspace needed for groups with
444        alternatives. The 1000-alternative test pattern now uses 12 bytes of
445        workspace instead of running out of the 4096 that are available.
446    
447    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
448    
449    11. Applied patch from Google to remove an optimization that didn't quite work.
450        The report of the bug said:
451    
452          pcrecpp::RE("a*").FullMatch("aaa") matches, while
453          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
454          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
455    
456    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
457        it matched the wrong number of bytes.
458    
459    
460    Version 7.1 24-Apr-07
461    ---------------------
462    
463     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
464        that is more "standard", making use of automake and other Autotools. There
465        is some re-arrangement of the files and adjustment of comments consequent
466        on this.
467    
468     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
469        for recursive directory scanning broke on some systems because the files
470        are not scanned in any specific order and on different systems the order
471        was different. A call to "sort" has been inserted into RunGrepTest for the
472        approprate test as a short-term fix. In the longer term there may be an
473        alternative.
474    
475     3. I had an email from Eric Raymond about problems translating some of PCRE's
476        man pages to HTML (despite the fact that I distribute HTML pages, some
477        people do their own conversions for various reasons). The problems
478        concerned the use of low-level troff macros .br and .in. I have therefore
479        removed all such uses from the man pages (some were redundant, some could
480        be replaced by .nf/.fi pairs). The 132html script that I use to generate
481        HTML has been updated to handle .nf/.fi and to complain if it encounters
482        .br or .in.
483    
484     4. Updated comments in configure.ac that get placed in config.h.in and also
485        arranged for config.h to be included in the distribution, with the name
486        config.h.generic, for the benefit of those who have to compile without
487        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
488    
489     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
490        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
491        makevp.bat for the current PCRE, using the additional files
492        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
493    
494     6. A Windows user reported a minor discrepancy with test 2, which turned out
495        to be caused by a trailing space on an input line that had got lost in his
496        copy. The trailing space was an accident, so I've just removed it.
497    
498     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
499        that is needed.
500    
501     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
502        as "const" (a) because they are and (b) because it helps the PHP
503        maintainers who have recently made a script to detect big data structures
504        in the php code that should be moved to the .rodata section. I remembered
505        to update Builducptable as well, so it won't revert if ucptable.h is ever
506        re-created.
507    
508     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
509        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
510        order to be able to cut out the UTF-8 tables in the latter when UTF-8
511        support is not required. This saves 1.5-2K of code, which is important in
512        some applications.
513    
514        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
515        so as not to refer to the tables, even though these functions will never be
516        called when UTF-8 support is disabled. Otherwise there are problems with a
517        shared library.
518    
519    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
520    
521        (a) It was defining its arguments as char * instead of void *.
522    
523        (b) It was assuming that all moves were upwards in memory; this was true
524            a long time ago when I wrote it, but is no longer the case.
525    
526        The emulated memove() is provided for those environments that have neither
527        memmove() nor bcopy(). I didn't think anyone used it these days, but that
528        is clearly not the case, as these two bugs were recently reported.
529    
530    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
531        and Detrail to create the HTML documentation, the .txt form of the man
532        pages, and it removes trailing spaces from listed files. It also creates
533        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
534        case, it wraps all the #defines with #ifndefs. This script should be run
535        before "make dist".
536    
537    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
538        with Unicode property support.
539    
540        (a) For a maximizing quantifier, if the two different cases of the
541            character were of different lengths in their UTF-8 codings (there are
542            some cases like this - I found 11), and the matching function had to
543            back up over a mixture of the two cases, it incorrectly assumed they
544            were both the same length.
545    
546        (b) When PCRE was configured to use the heap rather than the stack for
547            recursion during matching, it was not correctly preserving the data for
548            the other case of a UTF-8 character when checking ahead for a match
549            while processing a minimizing repeat. If the check also involved
550            matching a wide character, but failed, corruption could cause an
551            erroneous result when trying to check for a repeat of the original
552            character.
553    
554    13. Some tidying changes to the testing mechanism:
555    
556        (a) The RunTest script now detects the internal link size and whether there
557            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
558            values substituted by "configure". (The RunGrepTest script already did
559            this for UTF-8.) The configure.ac script no longer substitutes the
560            relevant variables.
561    
562        (b) The debugging options /B and /D in pcretest show the compiled bytecode
563            with length and offset values. This means that the output is different
564            for different internal link sizes. Test 2 is skipped for link sizes
565            other than 2 because of this, bypassing the problem. Unfortunately,
566            there was also a test in test 3 (the locale tests) that used /B and
567            failed for link sizes other than 2. Rather than cut the whole test out,
568            I have added a new /Z option to pcretest that replaces the length and
569            offset values with spaces. This is now used to make test 3 independent
570            of link size. (Test 2 will be tidied up later.)
571    
572    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
573        segmentation fault instead of returning the appropriate error message.
574    
575    15. In multiline mode when the newline sequence was set to "any", the pattern
576        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
577        This doesn't seem right; it now treats the CRLF combination as the line
578        ending, and so does not match in that case. It's only a pattern such as ^$
579        that would hit this one: something like ^ABC$ would have failed after \r
580        and then tried again after \r\n.
581    
582    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
583        in an attempt to make files that differ only in their line terminators
584        compare equal. This works on Linux.
585    
586    17. Under certain error circumstances pcregrep might try to free random memory
587        as it exited. This is now fixed, thanks to valgrind.
588    
589    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
590        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
591        was because its rules for how to advance for /g after matching an empty
592        string at the end of a line did not allow for this case. They now check for
593        it specially.
594    
595    20. pcretest is supposed to handle patterns and data of any length, by
596        extending its buffers when necessary. It was getting this wrong when the
597        buffer for a data line had to be extended.
598    
599    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
600        CRLF as a newline sequence.
601    
602    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
603        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
604        I have nevertheless tidied it up.
605    
606    23. Added some casts to kill warnings from HP-UX ia64 compiler.
607    
608    24. Added a man page for pcre-config.
609    
610    
611    Version 7.0 19-Dec-06
612    ---------------------
613    
614     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
615        moving to gcc 4.1.1.
616    
617     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
618        sys/time.h, which is documented as needed for this function. It doesn't
619        seem to matter on Linux, but it showed up on some releases of OS X.
620    
621     3. It seems that there are systems where bytes whose values are greater than
622        127 match isprint() in the "C" locale. The "C" locale should be the
623        default when a C program starts up. In most systems, only ASCII printing
624        characters match isprint(). This difference caused the output from pcretest
625        to vary, making some of the tests fail. I have changed pcretest so that:
626    
627        (a) When it is outputting text in the compiled version of a pattern, bytes
628            other than 32-126 are always shown as hex escapes.
629    
630        (b) When it is outputting text that is a matched part of a subject string,
631            it does the same, unless a different locale has been set for the match
632            (using the /L modifier). In this case, it uses isprint() to decide.
633    
634     4. Fixed a major bug that caused incorrect computation of the amount of memory
635        required for a compiled pattern when options that changed within the
636        pattern affected the logic of the preliminary scan that determines the
637        length. The relevant options are -x, and -i in UTF-8 mode. The result was
638        that the computed length was too small. The symptoms of this bug were
639        either the PCRE error "internal error: code overflow" from pcre_compile(),
640        or a glibc crash with a message such as "pcretest: free(): invalid next
641        size (fast)". Examples of patterns that provoked this bug (shown in
642        pcretest format) are:
643    
644          /(?-x: )/x
645          /(?x)(?-x: \s*#\s*)/
646          /((?i)[\x{c0}])/8
647          /(?i:[\x{c0}])/8
648    
649        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
650        is now done differently.
651    
652     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
653        wrapper classes; (b) implement a new function in the C++ scanner that is
654        more efficient than the old way of doing things because it avoids levels of
655        recursion in the regex matching; (c) add a paragraph to the documentation
656        for the FullMatch() function.
657    
658     6. The escape sequence \n was being treated as whatever was defined as
659        "newline". Not only was this contrary to the documentation, which states
660        that \n is character 10 (hex 0A), but it also went horribly wrong when
661        "newline" was defined as CRLF. This has been fixed.
662    
663     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
664        was being set to -1 for the "end of line" case (supposedly a value that no
665        character can have). Though this value is never used (the check for end of
666        line is "zero bytes in current character"), it caused compiler complaints.
667        I've changed it to 0xffffffff.
668    
669     8. In pcre_version.c, the version string was being built by a sequence of
670        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
671        string (as it is for production releases) called a macro with an empty
672        argument. The C standard says the result of this is undefined. The gcc
673        compiler treats it as an empty string (which was what was wanted) but it is
674        reported that Visual C gives an error. The source has been hacked around to
675        avoid this problem.
676    
677     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
678        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
679        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
680        of them did).
681    
682    10. Originally, pcretest opened its input and output without "b"; then I was
683        told that "b" was needed in some environments, so it was added for release
684        5.0 to both the input and output. (It makes no difference on Unix-like
685        systems.) Later I was told that it is wrong for the input on Windows. I've
686        now abstracted the modes into two macros, to make it easier to fiddle with
687        them, and removed "b" from the input mode under Windows.
688    
689    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
690    
691    12. Added -help and --help to pcretest as an official way of being reminded
692        of the options.
693    
694    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
695        and pcrecpp.cc because they annoy compilers at high warning levels.
696    
697    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
698    
699    15. Fixed an occurrence of == in configure.ac that should have been = (shell
700        scripts are not C programs :-) and which was not noticed because it works
701        on Linux.
702    
703    16. pcretest is supposed to handle any length of pattern and data line (as one
704        line or as a continued sequence of lines) by extending its input buffer if
705        necessary. This feature was broken for very long pattern lines, leading to
706        a string of junk being passed to pcre_compile() if the pattern was longer
707        than about 50K.
708    
709    17. I have done a major re-factoring of the way pcre_compile() computes the
710        amount of memory needed for a compiled pattern. Previously, there was code
711        that made a preliminary scan of the pattern in order to do this. That was
712        OK when PCRE was new, but as the facilities have expanded, it has become
713        harder and harder to keep it in step with the real compile phase, and there
714        have been a number of bugs (see for example, 4 above). I have now found a
715        cunning way of running the real compile function in a "fake" mode that
716        enables it to compute how much memory it would need, while actually only
717        ever using a few hundred bytes of working memory and without too many
718        tests of the mode. This should make future maintenance and development
719        easier. A side effect of this work is that the limit of 200 on the nesting
720        depth of parentheses has been removed (though this was never a serious
721        limitation, I suspect). However, there is a downside: pcre_compile() now
722        runs more slowly than before (30% or more, depending on the pattern). I
723        hope this isn't a big issue. There is no effect on runtime performance.
724    
725    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
726        newline (only possible for the last line of a file) and it was a
727        pattern that set a locale (followed by /Lsomething), pcretest crashed.
728    
729    19. Added additional timing features to pcretest. (1) The -tm option now times
730        matching only, not compiling. (2) Both -t and -tm can be followed, as a
731        separate command line item, by a number that specifies the number of
732        repeats to use when timing. The default is 50000; this gives better
733        precision, but takes uncomfortably long for very large patterns.
734    
735    20. Extended pcre_study() to be more clever in cases where a branch of a
736        subpattern has no definite first character. For example, (a*|b*)[cd] would
737        previously give no result from pcre_study(). Now it recognizes that the
738        first character must be a, b, c, or d.
739    
740    21. There was an incorrect error "recursive call could loop indefinitely" if
741        a subpattern (or the entire pattern) that was being tested for matching an
742        empty string contained only one non-empty item after a nested subpattern.
743        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
744        incorrectly, because the \d was being skipped in the check.
745    
746    22. The pcretest program now has a new pattern option /B and a command line
747        option -b, which is equivalent to adding /B to every pattern. This causes
748        it to show the compiled bytecode, without the additional information that
749        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
750        is the same as /B/I).
751    
752    23. A new optimization is now able automatically to treat some sequences such
753        as a*b as a*+b. More specifically, if something simple (such as a character
754        or a simple class like \d) has an unlimited quantifier, and is followed by
755        something that cannot possibly match the quantified thing, the quantifier
756        is automatically "possessified".
757    
758    24. A recursive reference to a subpattern whose number was greater than 39
759        went wrong under certain circumstances in UTF-8 mode. This bug could also
760        have affected the operation of pcre_study().
761    
762    25. Realized that a little bit of performance could be had by replacing
763        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
764    
765    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
766    
767    27. Possessive quantifiers such as a++ were previously implemented by turning
768        them into atomic groups such as ($>a+). Now they have their own opcodes,
769        which improves performance. This includes the automatically created ones
770        from 23 above.
771    
772    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
773        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
774        the first matched character to be a colon. This applied both to named and
775        numbered groups.
776    
777    29. The ucpinternal.h header file was missing its idempotency #ifdef.
778    
779    30. I was sent a "project" file called libpcre.a.dev which I understand makes
780        building PCRE on Windows easier, so I have included it in the distribution.
781    
782    31. There is now a check in pcretest against a ridiculously large number being
783        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
784        loop, the loop is abandoned.
785    
786    32. Forward references to subpatterns in conditions such as (?(2)...) where
787        subpattern 2 is defined later cause pcre_compile() to search forwards in
788        the pattern for the relevant set of parentheses. This search went wrong
789        when there were unescaped parentheses in a character class, parentheses
790        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
791    
792    33. "Subroutine" calls and backreferences were previously restricted to
793        referencing subpatterns earlier in the regex. This restriction has now
794        been removed.
795    
796    34. Added a number of extra features that are going to be in Perl 5.10. On the
797        whole, these are just syntactic alternatives for features that PCRE had
798        previously implemented using the Python syntax or my own invention. The
799        other formats are all retained for compatibility.
800    
801        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
802            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
803            also .NET compatible.
804    
805        (b) A recursion or subroutine call to a named group can now be defined as
806            (?&name) as well as (?P>name).
807    
808        (c) A backreference to a named group can now be defined as \k<name> or
809            \k'name' as well as (?P=name). The new forms, as well as being in Perl
810            5.10, are also .NET compatible.
811    
812        (d) A conditional reference to a named group can now use the syntax
813            (?(<name>) or (?('name') as well as (?(name).
814    
815        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
816            groups (named and numbered) that are never evaluated inline, but can be
817            called as "subroutines" from elsewhere. In effect, the DEFINE condition
818            is always false. There may be only one alternative in such a group.
819    
820        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
821            as the simple (?(R). The condition is true only if the most recent
822            recursion is that of the given number or name. It does not search out
823            through the entire recursion stack.
824    
825        (g) The escape \gN or \g{N} has been added, where N is a positive or
826            negative number, specifying an absolute or relative reference.
827    
828    35. Tidied to get rid of some further signed/unsigned compiler warnings and
829        some "unreachable code" warnings.
830    
831    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
832        things, this adds five new scripts.
833    
834    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
835        There were also incompatibilities regarding the handling of \Q..\E inside
836        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
837        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
838    
839    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
840        matches an empty string, and forcibly breaks the loop. There were bugs in
841        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
842        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
843        separate and independent bugs (that affected different cases) have been
844        fixed.
845    
846    39. Refactored the code to abolish the use of different opcodes for small
847        capturing bracket numbers. This is a tidy that I avoided doing when I
848        removed the limit on the number of capturing brackets for 3.5 back in 2001.
849        The new approach is not only tidier, it makes it possible to reduce the
850        memory needed to fix the previous bug (38).
851    
852    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
853        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
854        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
855        mode.
856    
857    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
858        report.
859    
860    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
861        copy construction and assignment in the C++ wrapper.
862    
863    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
864        couple of bugs that could have given wrong results in the "--newline=crlf"
865        case.
866    
867    44. Added a number of casts and did some reorganization of signed/unsigned int
868        variables following suggestions from Dair Grant. Also renamed the variable
869        "this" as "item" because it is a C++ keyword.
870    
871    45. Arranged for dftables to add
872    
873          #include "pcre_internal.h"
874    
875        to pcre_chartables.c because without it, gcc 4.x may remove the array
876        definition from the final binary if PCRE is built into a static library and
877        dead code stripping is activated.
878    
879    46. For an unanchored pattern, if a match attempt fails at the start of a
880        newline sequence, and the newline setting is CRLF or ANY, and the next two
881        characters are CRLF, advance by two characters instead of one.
882    
883    
884    Version 6.7 04-Jul-06
885    ---------------------
886    
887     1. In order to handle tests when input lines are enormously long, pcretest has
888        been re-factored so that it automatically extends its buffers when
889        necessary. The code is crude, but this _is_ just a test program. The
890        default size has been increased from 32K to 50K.
891    
892     2. The code in pcre_study() was using the value of the re argument before
893        testing it for NULL. (Of course, in any sensible call of the function, it
894        won't be NULL.)
895    
896     3. The memmove() emulation function in pcre_internal.h, which is used on
897        systems that lack both memmove() and bcopy() - that is, hardly ever -
898        was missing a "static" storage class specifier.
899    
900     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
901        containing an extended class (one that cannot be represented by a bitmap
902        because it contains high-valued characters or Unicode property items, e.g.
903        [\pZ]). Almost always one would set UTF-8 mode when processing such a
904        pattern, but PCRE should not loop if you do not (it no longer does).
905        [Detail: two cases were found: (a) a repeated subpattern containing an
906        extended class; (b) a recursive reference to a subpattern that followed a
907        previous extended class. It wasn't skipping over the extended class
908        correctly when UTF-8 mode was not set.]
909    
910     5. A negated single-character class was not being recognized as fixed-length
911        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
912        compile error "lookbehind assertion is not fixed length".
913    
914     6. The RunPerlTest auxiliary script was showing an unexpected difference
915        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
916        write a Perl script that can interpret lines of an input file either as
917        byte characters or as UTF-8, which is what "perltest" was being required to
918        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
919        can't do is switch easily at run time between having the "use utf8;" pragma
920        or not. In the end, I fudged it by using the RunPerlTest script to insert
921        "use utf8;" explicitly for the UTF-8 tests.
922    
923     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
924        the end of the subject string, contrary to the documentation and to what
925        Perl does. This was true of both matching functions. Now it matches only at
926        the start of the subject and immediately after *internal* newlines.
927    
928     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
929        a pointer to an int instead of a pointer to an unsigned long int. This
930        caused problems on 64-bit systems.
931    
932     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
933        instance of the 'standard' template library not being so standard".
934    
935    10. There was no check on the number of named subpatterns nor the maximum
936        length of a subpattern name. The product of these values is used to compute
937        the size of the memory block for a compiled pattern. By supplying a very
938        long subpattern name and a large number of named subpatterns, the size
939        computation could be caused to overflow. This is now prevented by limiting
940        the length of names to 32 characters, and the number of named subpatterns
941        to 10,000.
942    
943    11. Subpatterns that are repeated with specific counts have to be replicated in
944        the compiled pattern. The size of memory for this was computed from the
945        length of the subpattern and the repeat count. The latter is limited to
946        65535, but there was no limit on the former, meaning that integer overflow
947        could in principle occur. The compiled length of a repeated subpattern is
948        now limited to 30,000 bytes in order to prevent this.
949    
950    12. Added the optional facility to have named substrings with the same name.
951    
952    13. Added the ability to use a named substring as a condition, using the
953        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
954        are numbers (not recommended). Forward references are permitted.
955    
956    14. Added forward references in named backreferences (if you see what I mean).
957    
958    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
959        pattern could run off the end of the subject. For example, the pattern
960        "(?s)(.{1,5})"8 did this with the subject "ab".
961    
962    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
963        PCRE_CASELESS was set when matching characters that were quantified with ?
964        or *.
965    
966    17. A character class other than a single negated character that had a minimum
967        but no maximum quantifier - for example [ab]{6,} - was not handled
968        correctly by pce_dfa_exec(). It would match only one character.
969    
970    18. A valid (though odd) pattern that looked like a POSIX character
971        class but used an invalid character after [ (for example [[,abc,]]) caused
972        pcre_compile() to give the error "Failed: internal error: code overflow" or
973        in some cases to crash with a glibc free() error. This could even happen if
974        the pattern terminated after [[ but there just happened to be a sequence of
975        letters, a binary zero, and a closing ] in the memory that followed.
976    
977    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
978        over the years. Originally (before any Unicode support), just the bottom 8
979        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
980        output from "man perlunicode" includes this:
981    
982          The regular expression compiler produces polymorphic opcodes.  That
983          is, the pattern adapts to the data and automatically switches to
984          the Unicode character scheme when presented with Unicode data--or
985          instead uses a traditional byte scheme when presented with byte
986          data.
987    
988        Sadly, a wide octal escape does not cause a switch, and in a string with
989        no other multibyte characters, these octal escapes are treated as before.
990        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
991        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
992        Unicode string.
993    
994        I have not perpetrated such confusion in PCRE. Up till now, it took just
995        the bottom 8 bits, as in old Perl. I have now made octal escapes with
996        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
997        translate to the appropriate multibyte character.
998    
999    29. Applied some refactoring to reduce the number of warnings from Microsoft
1000        and Borland compilers. This has included removing the fudge introduced
1001        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1002        a warning about an unused variable.
1003    
1004    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1005        characters since release 4.0, because Perl (from release 5.004) does not.
1006        [Or at least, is documented not to: some releases seem to be in conflict
1007        with the documentation.] However, when a pattern was studied with
1008        pcre_study() and all its branches started with \s, PCRE still included VT
1009        as a possible starting character. Of course, this did no harm; it just
1010        caused an unnecessary match attempt.
1011    
1012    22. Removed a now-redundant internal flag bit that recorded the fact that case
1013        dependency changed within the pattern. This was once needed for "required
1014        byte" processing, but is no longer used. This recovers a now-scarce options
1015        bit. Also moved the least significant internal flag bit to the most-
1016        significant bit of the word, which was not previously used (hangover from
1017        the days when it was an int rather than a uint) to free up another bit for
1018        the future.
1019    
1020    23. Added support for CRLF line endings as well as CR and LF. As well as the
1021        default being selectable at build time, it can now be changed at runtime
1022        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1023        specify that it is scanning data with non-default line endings.
1024    
1025    24. Changed the definition of CXXLINK to make it agree with the definition of
1026        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1027    
1028    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1029        recursions. This makes a big different to stack usage for some patterns.
1030    
1031    26. If a subpattern containing a named recursion or subroutine reference such
1032        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1033        the space required for the compiled pattern went wrong and gave too small a
1034        value. Depending on the environment, this could lead to "Failed: internal
1035        error: code overflow at offset 49" or "glibc detected double free or
1036        corruption" errors.
1037    
1038    27. Applied patches from Google (a) to support the new newline modes and (b) to
1039        advance over multibyte UTF-8 characters in GlobalReplace.
1040    
1041    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1042        difference for some implementation of PCRE in some Windows version.
1043    
1044    29. Added some extra testing facilities to pcretest:
1045    
1046        \q<number>   in a data line sets the "match limit" value
1047        \Q<number>   in a data line sets the "match recursion limt" value
1048        -S <number>  sets the stack size, where <number> is in megabytes
1049    
1050        The -S option isn't available for Windows.
1051    
1052    
1053    Version 6.6 06-Feb-06
1054    ---------------------
1055    
1056     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1057        in pcreposix.h. I have copied the definition from pcre.h.
1058    
1059     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1060        because pcre.h is no longer a built file.
1061    
1062     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1063        not normally included in the compiled code.
1064    
1065    
1066    Version 6.5 01-Feb-06
1067    ---------------------
1068    
1069     1. When using the partial match feature with pcre_dfa_exec(), it was not
1070        anchoring the second and subsequent partial matches at the new starting
1071        point. This could lead to incorrect results. For example, with the pattern
1072        /1234/, partially matching against "123" and then "a4" gave a match.
1073    
1074     2. Changes to pcregrep:
1075    
1076        (a) All non-match returns from pcre_exec() were being treated as failures
1077            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1078            error message is output. Some extra information is given for the
1079            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1080            probably the only errors that are likely to be caused by users (by
1081            specifying a regex that has nested indefinite repeats, for instance).
1082            If there are more than 20 of these errors, pcregrep is abandoned.
1083    
1084        (b) A binary zero was treated as data while matching, but terminated the
1085            output line if it was written out. This has been fixed: binary zeroes
1086            are now no different to any other data bytes.
1087    
1088        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1089            used to set a locale for matching. The --locale=xxxx long option has
1090            been added (no short equivalent) to specify a locale explicitly on the
1091            pcregrep command, overriding the environment variables.
1092    
1093        (d) When -B was used with -n, some line numbers in the output were one less
1094            than they should have been.
1095    
1096        (e) Added the -o (--only-matching) option.
1097    
1098        (f) If -A or -C was used with -c (count only), some lines of context were
1099            accidentally printed for the final match.
1100    
1101        (g) Added the -H (--with-filename) option.
1102    
1103        (h) The combination of options -rh failed to suppress file names for files
1104            that were found from directory arguments.
1105    
1106        (i) Added the -D (--devices) and -d (--directories) options.
1107    
1108        (j) Added the -F (--fixed-strings) option.
1109    
1110        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1111    
1112        (l) Added the --colo(u)r option.
1113    
1114        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1115            is not present by default.
1116    
1117     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1118        items such as (?R) or (?1), when the recursion could match a number of
1119        alternatives. If it matched one of the alternatives, but subsequently,
1120        outside the recursion, there was a failure, the code tried to back up into
1121        the recursion. However, because of the way PCRE is implemented, this is not
1122        possible, and the result was an incorrect result from the match.
1123    
1124        In order to prevent this happening, the specification of recursion has
1125        been changed so that all such subpatterns are automatically treated as
1126        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1127    
1128     4. I had overlooked the fact that, in some locales, there are characters for
1129        which isalpha() is true but neither isupper() nor islower() are true. In
1130        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1131        and ordfeminine) are like this. This affected the treatment of \w and \W
1132        when they appeared in character classes, but not when they appeared outside
1133        a character class. The bit map for "word" characters is now created
1134        separately from the results of isalnum() instead of just taking it from the
1135        upper, lower, and digit maps. (Plus the underscore character, of course.)
1136    
1137     5. The above bug also affected the handling of POSIX character classes such as
1138        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1139        permanent tables. Instead, the bit maps for such a class were previously
1140        created as the appropriate unions of the upper, lower, and digit bitmaps.
1141        Now they are created by subtraction from the [[:word:]] class, which has
1142        its own bitmap.
1143    
1144     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1145        It is created by subtracting the vertical space characters (\x09, \x0a,
1146        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1147        subtraction was done in the overall bitmap for a character class, meaning
1148        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1149        be recognized. This bug has been fixed.
1150    
1151     7. Patches from the folks at Google:
1152    
1153          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1154          real life, but is still worth protecting against".
1155    
1156          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1157          regular expressions".
1158    
1159          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1160          have it.
1161    
1162          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1163          "configure" and the latter not, in order to fix a problem somebody had
1164          with compiling the Arg class on HP-UX.
1165    
1166          (e) Improve the error-handling of the C++ wrapper a little bit.
1167    
1168          (f) New tests for checking recursion limiting.
1169    
1170     8. The pcre_memmove() function, which is used only if the environment does not
1171        have a standard memmove() function (and is therefore rarely compiled),
1172        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1173        returning a result (though PCRE never actually uses the result).
1174    
1175     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1176        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1177        returned instead of calling malloc() with an overflowing number that would
1178        most likely cause subsequent chaos.
1179    
1180    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1181    
1182    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1183        with this option is matched, the nmatch and pmatch options of regexec() are
1184        ignored.
1185    
1186    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1187        provided in case anyone wants to the the POSIX interface with UTF-8
1188        strings.
1189    
1190    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1191        C++ linking (needed for some HP-UX environments).
1192    
1193    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1194        (unused parameter) and in the pcre_printint() function (omitted "default"
1195        switch label when the default is to do nothing).
1196    
1197    15. Added some code to make it possible, when PCRE is compiled as a C++
1198        library, to replace subject pointers for pcre_exec() with a smart pointer
1199        class, thus making it possible to process discontinuous strings.
1200    
1201    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1202        much the same function. They were added by different people who were trying
1203        to make PCRE easy to compile on non-Unix systems. It has been suggested
1204        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1205        for compiling on Windows systems. I have therefore replaced it with
1206        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1207        defaults to "extern" for C or "extern C" for C++, which works fine on
1208        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1209        SCOPE with something explicit in config.h. In addition:
1210    
1211        (a) pcreposix.h still had just "extern" instead of either of these macros;
1212            I have replaced it with PCRE_DATA_SCOPE.
1213    
1214        (b) Functions such as _pcre_xclass(), which are internal to the library,
1215            but external in the C sense, all had PCRE_EXPORT in their definitions.
1216            This is apparently wrong for the Windows case, so I have removed it.
1217            (It makes no difference on Unix-like systems.)
1218    
1219    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1220        of recursive calls to match(). This is different to MATCH_LIMIT because
1221        that limits the total number of calls to match(), not all of which increase
1222        the depth of recursion. Limiting the recursion depth limits the amount of
1223        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1224        when PCRE is compiled, and changed at run time. A patch from Google adds
1225        this functionality to the C++ interface.
1226    
1227    18. Changes to the handling of Unicode character properties:
1228    
1229        (a) Updated the table to Unicode 4.1.0.
1230    
1231        (b) Recognize characters that are not in the table as "Cn" (undefined).
1232    
1233        (c) I revised the way the table is implemented to a much improved format
1234            which includes recognition of ranges. It now supports the ranges that
1235            are defined in UnicodeData.txt, and it also amalgamates other
1236            characters into ranges. This has reduced the number of entries in the
1237            table from around 16,000 to around 3,000, thus reducing its size
1238            considerably. I realized I did not need to use a tree structure after
1239            all - a binary chop search is just as efficient. Having reduced the
1240            number of entries, I extended their size from 6 bytes to 8 bytes to
1241            allow for more data.
1242    
1243        (d) Added support for Unicode script names via properties such as \p{Han}.
1244    
1245    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1246        matching that character.
1247    
1248    20. When matching a repeated Unicode property with a minimum greater than zero,
1249        (for example \pL{2,}), PCRE could look past the end of the subject if it
1250        reached it while seeking the minimum number of characters. This could
1251        happen only if some of the characters were more than one byte long, because
1252        there is a check for at least the minimum number of bytes.
1253    
1254    21. Refactored the implementation of \p and \P so as to be more general, to
1255        allow for more different types of property in future. This has changed the
1256        compiled form incompatibly. Anybody with saved compiled patterns that use
1257        \p or \P will have to recompile them.
1258    
1259    22. Added "Any" and "L&" to the supported property types.
1260    
1261    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1262        but give a compile time error if the value is greater than 0xff.
1263    
1264    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1265        accidentally not being installed or uninstalled.
1266    
1267    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1268        made were to insert the current release number. This seemed silly, because
1269        it made things harder for people building PCRE on systems that don't run
1270        "configure". I have turned pcre.h into a distributed file, no longer built
1271        by "configure", with the version identification directly included. There is
1272        no longer a pcre.h.in file.
1273    
1274        However, this change necessitated a change to the pcre-config script as
1275        well. It is built from pcre-config.in, and one of the substitutions was the
1276        release number. I have updated configure.ac so that ./configure now finds
1277        the release number by grepping pcre.h.
1278    
1279    26. Added the ability to run the tests under valgrind.
1280    
1281    
1282    Version 6.4 05-Sep-05
1283    ---------------------
1284    
1285     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1286        "--" to be printed when multiple files were scanned, even when none of the
1287        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1288        consider it to be a bug, and have restored the previous behaviour.
1289    
1290     2. A couple of code tidies to get rid of compiler warnings.
1291    
1292     3. The pcretest program used to cheat by referring to symbols in the library
1293        whose names begin with _pcre_. These are internal symbols that are not
1294        really supposed to be visible externally, and in some environments it is
1295        possible to suppress them. The cheating is now confined to including
1296        certain files from the library's source, which is a bit cleaner.
1297    
1298     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1299        file's purpose clearer.
1300    
1301     5. Reorganized pcre_ucp_findchar().
1302    
1303    
1304    Version 6.3 15-Aug-05
1305    ---------------------
1306    
1307     1. The file libpcre.pc.in did not have general read permission in the tarball.
1308    
1309     2. There were some problems when building without C++ support:
1310    
1311        (a) If C++ support was not built, "make install" and "make test" still
1312            tried to test it.
1313    
1314        (b) There were problems when the value of CXX was explicitly set. Some
1315            changes have been made to try to fix these, and ...
1316    
1317        (c) --disable-cpp can now be used to explicitly disable C++ support.
1318    
1319        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1320            backslash in a target when C++ was disabled. This confuses some
1321            versions of "make", apparently. Using an intermediate variable solves
1322            this. (Same for CPP_LOBJ.)
1323    
1324     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1325        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1326        necessary on certain architectures.
1327    
1328     4. Added a setting of -export-symbols-regex to the link command to remove
1329        those symbols that are exported in the C sense, but actually are local
1330        within the library, and not documented. Their names all begin with
1331        "_pcre_". This is not a perfect job, because (a) we have to except some
1332        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1333        available (and never for static libraries). I have made a note to try to
1334        find a way round (a) in the future.
1335    
1336    
1337    Version 6.2 01-Aug-05
1338    ---------------------
1339    
1340     1. There was no test for integer overflow of quantifier values. A construction
1341        such as {1111111111111111} would give undefined results. What is worse, if
1342        a minimum quantifier for a parenthesized subpattern overflowed and became
1343        negative, the calculation of the memory size went wrong. This could have
1344        led to memory overwriting.
1345    
1346     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1347    
1348     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1349        operating environments where this matters.
1350    
1351     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1352        PCRE options from within the C++ wrapper.
1353    
1354     5. Named capturing subpatterns were not being correctly counted when a pattern
1355        was compiled. This caused two problems: (a) If there were more than 100
1356        such subpatterns, the calculation of the memory needed for the whole
1357        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1358        back references of the form \12, where the number was greater than 9, were
1359        not recognized as back references, even though there were sufficient
1360        previous subpatterns.
1361    
1362     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1363        versions of gcc, e.g. 2.95.4.
1364    
1365    
1366    Version 6.1 21-Jun-05
1367    ---------------------
1368    
1369     1. There was one reference to the variable "posix" in pcretest.c that was not
1370        surrounded by "#if !defined NOPOSIX".
1371    
1372     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1373        the cross-check on the old pcre_info() function, for the benefit of the
1374        cut-down version of PCRE that is currently imported into Exim.
1375    
1376     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1377        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1378        patterns that start (?i) but I don't think that matters. The use of (?i) is
1379        just an example; this all applies to the other options as well.
1380    
1381     4. Since libtool seems to echo the compile commands it is issuing, the output
1382        from "make" can be reduced a bit by putting "@" in front of each libtool
1383        compile command.
1384    
1385     5. Patch from the folks at Google for configure.in to be a bit more thorough
1386        in checking for a suitable C++ installation before trying to compile the
1387        C++ stuff. This should fix a reported problem when a compiler was present,
1388        but no suitable headers.
1389    
1390     6. The man pages all had just "PCRE" as their title. I have changed them to
1391        be the relevant file name. I have also arranged that these names are
1392        retained in the file doc/pcre.txt, which is a concatenation in text format
1393        of all the man pages except the little individual ones for each function.
1394    
1395     7. The NON-UNIX-USE file had not been updated for the different set of source
1396        files that come with release 6. I also added a few comments about the C++
1397        wrapper.
1398    
1399    
1400    Version 6.0 07-Jun-05
1401    ---------------------
1402    
1403     1. Some minor internal re-organization to help with my DFA experiments.
1404    
1405     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1406        didn't matter for the library itself when fully configured, but did matter
1407        when compiling without UCP support, or within Exim, where the ucp files are
1408        not imported.
1409    
1410     3. Refactoring of the library code to split up the various functions into
1411        different source modules. The addition of the new DFA matching code (see
1412        below) to a single monolithic source would have made it really too
1413        unwieldy, quite apart from causing all the code to be include in a
1414        statically linked application, when only some functions are used. This is
1415        relevant even without the DFA addition now that patterns can be compiled in
1416        one application and matched in another.
1417    
1418        The downside of splitting up is that there have to be some external
1419        functions and data tables that are used internally in different modules of
1420        the library but which are not part of the API. These have all had their
1421        names changed to start with "_pcre_" so that they are unlikely to clash
1422        with other external names.
1423    
1424     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1425        a different (DFA) algorithm. Although it is slower than the original
1426        function, it does have some advantages for certain types of matching
1427        problem.
1428    
1429     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1430        including restarting after a partial match.
1431    
1432     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1433        defined when compiling for Windows was sent to me. I have put it into the
1434        code, though I have no means of testing or verifying it.
1435    
1436     7. Added the pcre_refcount() auxiliary function.
1437    
1438     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1439        match before or at the first newline in the subject string. In pcretest,
1440        the /f option on a pattern can be used to set this.
1441    
1442     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1443        would behave wrongly. This has been present in PCRE since release 4.0.
1444    
1445    10. A number of changes to the pcregrep command:
1446    
1447        (a) Refactored how -x works; insert ^(...)$ instead of setting
1448            PCRE_ANCHORED and checking the length, in preparation for adding
1449            something similar for -w.
1450    
1451        (b) Added the -w (match as a word) option.
1452    
1453        (c) Refactored the way lines are read and buffered so as to have more
1454            than one at a time available.
1455    
1456        (d) Implemented a pcregrep test script.
1457    
1458        (e) Added the -M (multiline match) option. This allows patterns to match
1459            over several lines of the subject. The buffering ensures that at least
1460            8K, or the rest of the document (whichever is the shorter) is available
1461            for matching (and similarly the previous 8K for lookbehind assertions).
1462    
1463        (f) Changed the --help output so that it now says
1464    
1465              -w, --word-regex(p)
1466    
1467            instead of two lines, one with "regex" and the other with "regexp"
1468            because that confused at least one person since the short forms are the
1469            same. (This required a bit of code, as the output is generated
1470            automatically from a table. It wasn't just a text change.)
1471    
1472        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1473            option but starts with a hyphen. Could be a pattern or a path name
1474            starting with a hyphen, for instance.
1475    
1476        (h) "-" can be given as a file name to represent stdin.
1477    
1478        (i) When file names are being printed, "(standard input)" is used for
1479            the standard input, for compatibility with GNU grep. Previously
1480            "<stdin>" was used.
1481    
1482        (j) The option --label=xxx can be used to supply a name to be used for
1483            stdin when file names are being printed. There is no short form.
1484    
1485        (k) Re-factored the options decoding logic because we are going to add
1486            two more options that take data. Such options can now be given in four
1487            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1488    
1489        (l) Added the -A, -B, and -C options for requesting that lines of context
1490            around matches be printed.
1491    
1492        (m) Added the -L option to print the names of files that do not contain
1493            any matching lines, that is, the complement of -l.
1494    
1495        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1496            continue to scan other files.
1497    
1498        (o) The -s option was incorrectly implemented. For compatibility with other
1499            greps, it now suppresses the error message for a non-existent or non-
1500            accessible file (but not the return code). There is a new option called
1501            -q that suppresses the output of matching lines, which was what -s was
1502            previously doing.
1503    
1504        (p) Added --include and --exclude options to specify files for inclusion
1505            and exclusion when recursing.
1506    
1507    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1508        Hopefully, it now does.
1509    
1510    12. Missing cast in pcre_study().
1511    
1512    13. Added an "uninstall" target to the makefile.
1513    
1514    14. Replaced "extern" in the function prototypes in Makefile.in with
1515        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1516        world, but is set differently for Windows.
1517    
1518    15. Added a second compiling function called pcre_compile2(). The only
1519        difference is that it has an extra argument, which is a pointer to an
1520        integer error code. When there is a compile-time failure, this is set
1521        non-zero, in addition to the error test pointer being set to point to an
1522        error message. The new argument may be NULL if no error number is required
1523        (but then you may as well call pcre_compile(), which is now just a
1524        wrapper). This facility is provided because some applications need a
1525        numeric error indication, but it has also enabled me to tidy up the way
1526        compile-time errors are handled in the POSIX wrapper.
1527    
1528    16. Added VPATH=.libs to the makefile; this should help when building with one
1529        prefix path and installing with another. (Or so I'm told by someone who
1530        knows more about this stuff than I do.)
1531    
1532    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1533        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1534        match everything, including newlines. This is not POSIX-compatible, but
1535        somebody wanted the feature. From pcretest it can be activated by using
1536        both the P and the s flags.
1537    
1538    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1539    
1540    19. libpcre.pc was being incorrectly installed as executable.
1541    
1542    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1543        it now also looks for '\r' so that it will work unmodified on Windows.
1544    
1545    21. Added Google's contributed C++ wrapper to the distribution.
1546    
1547    22. Added some untidy missing memory free() calls in pcretest, to keep
1548        Electric Fence happy when testing.
1549    
1550    
1551    
1552    Version 5.0 13-Sep-04
1553    ---------------------
1554    
1555     1. Internal change: literal characters are no longer packed up into items
1556        containing multiple characters in a single byte-string. Each character
1557        is now matched using a separate opcode. However, there may be more than one
1558        byte in the character in UTF-8 mode.
1559    
1560     2. The pcre_callout_block structure has two new fields: pattern_position and
1561        next_item_length. These contain the offset in the pattern to the next match
1562        item, and its length, respectively.
1563    
1564     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1565        insertion of callouts before each pattern item. Added the /C option to
1566        pcretest to make use of this.
1567    
1568     4. On the advice of a Windows user, the lines
1569    
1570          #if defined(_WIN32) || defined(WIN32)
1571          _setmode( _fileno( stdout ), 0x8000 );
1572          #endif  /* defined(_WIN32) || defined(WIN32) */
1573    
1574        have been added to the source of pcretest. This apparently does useful
1575        magic in relation to line terminators.
1576    
1577     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1578        for the benefit of those environments where the "b" makes a difference.
1579    
1580     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1581        to know about it. I have put a hack into configure.in that adds in code
1582        to set GCC=yes if CC=icc. This seems to end up at a point in the
1583        generated configure script that is early enough to affect the setting of
1584        compiler options, which is what is needed, but I have no means of testing
1585        whether it really works. (The user who reported this had patched the
1586        generated configure script, which of course I cannot do.)
1587    
1588        LATER: After change 22 below (new libtool files), the configure script
1589        seems to know about icc (and also ecc). Therefore, I have commented out
1590        this hack in configure.in.
1591    
1592     7. Added support for pkg-config (2 patches were sent in).
1593    
1594     8. Negated POSIX character classes that used a combination of internal tables
1595        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1596        [[:^ascii]]. Typically, they would match almost any characters. The other
1597        POSIX classes were not broken in this way.
1598    
1599     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1600        to find the match, as PCRE was deluded into thinking that the match had to
1601        start at the start point or following a newline. The same bug applied to
1602        patterns with negative forward assertions or any backward assertions
1603        preceding ".*" at the start, unless the pattern required a fixed first
1604        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1605    
1606    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1607        starting at the last subject character, bytes beyond the end of the subject
1608        string were read.
1609    
1610    11. Renamed the variable "class" as "classbits" to make life easier for C++
1611        users. (Previously there was a macro definition, but it apparently wasn't
1612        enough.)
1613    
1614    12. Added the new field "tables" to the extra data so that tables can be passed
1615        in at exec time, or the internal tables can be re-selected. This allows
1616        a compiled regex to be saved and re-used at a later time by a different
1617        program that might have everything at different addresses.
1618    
1619    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1620        -R library as well as a -L library.
1621    
1622    14. The debugging options of pcretest (-d on the command line or D on a
1623        pattern) showed incorrect output for anything following an extended class
1624        that contained multibyte characters and which was followed by a quantifier.
1625    
1626    15. Added optional support for general category Unicode character properties
1627        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1628        support. It adds about 90K to the size of the library. The meanings of the
1629        inbuilt class escapes such as \d and \s have NOT been changed.
1630    
1631    16. Updated pcredemo.c to include calls to free() to release the memory for the
1632        compiled pattern.
1633    
1634    17. The generated file chartables.c was being created in the source directory
1635        instead of in the building directory. This caused the build to fail if the
1636        source directory was different from the building directory, and was
1637        read-only.
1638    
1639    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1640        file. No doubt somebody will tell me if they don't make sense... Also added
1641        Dan Mooney's comments about building on OpenVMS.
1642    
1643    19. Added support for partial matching via the PCRE_PARTIAL option for
1644        pcre_exec() and the \P data escape in pcretest.
1645    
1646    20. Extended pcretest with 3 new pattern features:
1647    
1648        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1649              write the compiled pattern to the file whose name is "rest-of-line".
1650              This is a straight binary dump of the data, with the saved pointer to
1651              the character tables forced to be NULL. The study data, if any, is
1652              written too. After writing, pcretest reads a new pattern.
1653    
1654        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1655              compiled pattern from the given file. There must not be any
1656              occurrences of "<" in the file name (pretty unlikely); if there are,
1657              pcretest will instead treat the initial "<" as a pattern delimiter.
1658              After reading in the pattern, pcretest goes on to read data lines as
1659              usual.
1660    
1661        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1662              and 16-bit fields in a compiled pattern, to simulate a pattern that
1663              was compiled on a host of opposite endianness.
1664    
1665    21. The pcre-exec() function can now cope with patterns that were compiled on
1666        hosts of opposite endianness, with this restriction:
1667    
1668          As for any compiled expression that is saved and used later, the tables
1669          pointer field cannot be preserved; the extra_data field in the arguments
1670          to pcre_exec() should be used to pass in a tables address if a value
1671          other than the default internal tables were used at compile time.
1672    
1673    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1674        now diagnosed as an error. Previously, most of the time, a negative number
1675        would have been treated as zero, but if in addition "ovector" was passed as
1676        NULL, a crash could occur.
1677    
1678    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1679        new versions from the libtool 1.5 distribution (the last one is a copy of
1680        a file called libtool.m4). This seems to have fixed the need to patch
1681        "configure" to support Darwin 1.3 (which I used to do). However, I still
1682        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1683        workstation).
1684    
1685    24. Changed the PCRE licence to be the more standard "BSD" licence.
1686    
1687    
1688    Version 4.5 01-Dec-03
1689    ---------------------
1690    
1691     1. There has been some re-arrangement of the code for the match() function so
1692        that it can be compiled in a version that does not call itself recursively.
1693        Instead, it keeps those local variables that need separate instances for
1694        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1695        needs to "recurse". Keeping track of where control must go is done by means
1696        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1697        hide most of the details from the main code, and operates only if
1698        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1699        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1700        operating.
1701    
1702        To make it easier for callers to provide specially tailored get/free
1703        functions for this usage, two new functions, pcre_stack_malloc, and
1704        pcre_stack_free, are used. They are always called in strict stacking order,
1705        and the size of block requested is always the same.
1706    
1707        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1708        PCRE has been compiled to use the stack or the heap for recursion. The
1709        -C option of pcretest uses this to show which version is compiled.
1710    
1711        A new data escape \S, is added to pcretest; it causes the amounts of store
1712        obtained and freed by both kinds of malloc/free at match time to be added
1713        to the output.
1714    
1715     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1716        what's available on my current Linux desktop machine.
1717    
1718     3. When matching a UTF-8 string, the test for a valid string at the start has
1719        been extended. If start_offset is not zero, PCRE now checks that it points
1720        to a byte that is the start of a UTF-8 character. If not, it returns
1721        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1722        this is necessary because there may be backward assertions in the pattern.
1723        When matching the same subject several times, it may save resources to use
1724        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1725    
1726     4. The code for checking the validity of UTF-8 strings has been tightened so
1727        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1728        containing "overlong sequences".
1729    
1730     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1731        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1732        should have been "&", but it just so happened that all the cases this let
1733        through by mistake were picked up later in the function.
1734    
1735     6. I had used a variable called "isblank" - this is a C99 function, causing
1736        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1737    
1738     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1739        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1740        so the version is shown; (c) stop "make test" echoing "./RunTest".
1741    
1742     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1743    
1744     9. The prototype for memmove() for systems that don't have it was using
1745        size_t, but the inclusion of the header that defines size_t was later. I've
1746        moved the #includes for the C headers earlier to avoid this.
1747    
1748    10. Added some adjustments to the code to make it easier to compiler on certain
1749        special systems:
1750    
1751          (a) Some "const" qualifiers were missing.
1752          (b) Added the macro EXPORT before all exported functions; by default this
1753              is defined to be empty.
1754          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1755              that it reads its output file name as an argument instead of writing
1756              to the standard output and assuming this can be redirected.
1757    
1758    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1759        class containing characters with values greater than 255, PCRE compilation
1760        went into a loop.
1761    
1762    12. A recursive reference to a subpattern that was within another subpattern
1763        that had a minimum quantifier of zero caused PCRE to crash. For example,
1764        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1765        recursion. If the recursively-called subpattern itself had a zero repeat,
1766        that was OK.
1767    
1768    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1769        buffer into which it was copied (for escape processing) was still set at
1770        1024, so long lines caused crashes.
1771    
1772    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1773        "internal error: code overflow...". This applied to any character class
1774        that was followed by a possessive quantifier.
1775    
1776    15. Modified the Makefile to add libpcre.la as a prerequisite for
1777        libpcreposix.la because I was told this is needed for a parallel build to
1778        work.
1779    
1780    16. If a pattern that contained .* following optional items at the start was
1781        studied, the wrong optimizing data was generated, leading to matching
1782        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1783        matching string must start with a or b or c. The correct conclusion for
1784        this pattern is that a match can start with any character.
1785    
1786    
1787    Version 4.4 13-Aug-03
1788    ---------------------
1789    
1790     1. In UTF-8 mode, a character class containing characters with values between
1791        127 and 255 was not handled correctly if the compiled pattern was studied.
1792        In fixing this, I have also improved the studying algorithm for such
1793        classes (slightly).
1794    
1795     2. Three internal functions had redundant arguments passed to them. Removal
1796        might give a very teeny performance improvement.
1797    
1798     3. Documentation bug: the value of the capture_top field in a callout is *one
1799        more than* the number of the hightest numbered captured substring.
1800    
1801     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1802        in incorrectly linking with a previously installed version. They now link
1803        explicitly with libpcre.la.
1804    
1805     5. configure.in no longer needs to recognize Cygwin specially.
1806    
1807     6. A problem in pcre.in for Windows platforms is fixed.
1808    
1809     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1810        pcretest, it used to include the size of the study block as part of its
1811        output. Unfortunately, the structure contains a field that has a different
1812        size on different hardware architectures. This meant that the tests that
1813        showed this size failed. As the block is currently always of a fixed size,
1814        this information isn't actually particularly useful in pcretest output, so
1815        I have just removed it.
1816    
1817     8. Three pre-processor statements accidentally did not start in column 1.
1818        Sadly, there are *still* compilers around that complain, even though
1819        standard C has not required this for well over a decade. Sigh.
1820    
1821     9. In pcretest, the code for checking callouts passed small integers in the
1822        callout_data field, which is a void * field. However, some picky compilers
1823        complained about the casts involved for this on 64-bit systems. Now
1824        pcretest passes the address of the small integer instead, which should get
1825        rid of the warnings.
1826    
1827    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1828        both compile and run time, and gives an error if an invalid UTF-8 sequence
1829        is found. There is a option for disabling this check in cases where the
1830        string is known to be correct and/or the maximum performance is wanted.
1831    
1832    11. In response to a bug report, I changed one line in Makefile.in from
1833    
1834            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1835        to
1836            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1837    
1838        to look similar to other lines, but I have no way of telling whether this
1839        is the right thing to do, as I do not use Windows. No doubt I'll get told
1840        if it's wrong...
1841    
1842    
1843    Version 4.3 21-May-03
1844    ---------------------
1845    
1846    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1847       Makefile.
1848    
1849    2. Some refactoring to improve the quality of the code:
1850    
1851       (i)   The utf8_table... variables are now declared "const".
1852    
1853       (ii)  The code for \cx, which used the "case flipping" table to upper case
1854             lower case letters, now just substracts 32. This is ASCII-specific,
1855             but the whole concept of \cx is ASCII-specific, so it seems
1856             reasonable.
1857    
1858       (iii) PCRE was using its character types table to recognize decimal and
1859             hexadecimal digits in the pattern. This is silly, because it handles
1860             only 0-9, a-f, and A-F, but the character types table is locale-
1861             specific, which means strange things might happen. A private
1862             table is now used for this - though it costs 256 bytes, a table is
1863             much faster than multiple explicit tests. Of course, the standard
1864             character types table is still used for matching digits in subject
1865             strings against \d.
1866    
1867       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1868             ending in _t are). So I've renamed it as ESC_tee.
1869    
1870    3. The first argument for regexec() in the POSIX wrapper should have been
1871       defined as "const".
1872    
1873    4. Changed pcretest to use malloc() for its buffers so that they can be
1874       Electric Fenced for debugging.
1875    
1876    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1877       to read one or more bytes before the start of the subject string. Often this
1878       had no effect on PCRE's behaviour, but in some circumstances it could
1879       provoke a segmentation fault.
1880    
1881    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1882       to try to read one or more bytes before the start of the subject string.
1883    
1884    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1885       UTF-8 support could misbehave in various ways if the subject string
1886       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1887       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1888       back over UTF-8 characters.)
1889    
1890    
1891    Version 4.2 14-Apr-03
1892    ---------------------
1893    
1894    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1895    
1896    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
1897         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
1898         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
1899         [WIN_PREFIX]: new variable, "cyg" for Cygwin
1900         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
1901           and BUILD_EXEEXT
1902         Note: automatic setting of the BUILD variables is not yet working
1903         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
1904           compile-time but not at link-time
1905         [LINK]: use for linking executables only
1906         make different versions for Windows and non-Windows
1907         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
1908           libraries
1909         [LINK_FOR_BUILD]: new variable
1910         [OBJEXT]: use throughout
1911         [EXEEXT]: use throughout
1912         <winshared>: new target
1913         <wininstall>: new target
1914         <dftables.o>: use native compiler
1915         <dftables>: use native linker
1916         <install>: handle Windows platform correctly
1917         <clean>: ditto
1918         <check>: ditto
1919         copy DLL to top builddir before testing
1920    
1921       As part of these changes, -no-undefined was removed again. This was reported
1922       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
1923       in any case.
1924    
1925    3. Some tidies to get rid of compiler warnings:
1926    
1927       . In the match_data structure, match_limit was an unsigned long int, whereas
1928         match_call_count was an int. I've made them both unsigned long ints.
1929    
1930       . In pcretest the fact that a const uschar * doesn't automatically cast to
1931         a void * provoked a warning.
1932    
1933       . Turning on some more compiler warnings threw up some "shadow" variables
1934         and a few more missing casts.
1935    
1936    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
1937       option, a class that contained a single character with a value between 128
1938       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
1939    
1940    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
1941       option, a class that contained several characters, but with at least one
1942       whose value was between 128 and 255 caused PCRE to crash.
1943    
1944    
1945    Version 4.1 12-Mar-03
1946    ---------------------
1947    
1948    1. Compiling with gcc -pedantic found a couple of places where casts were
1949    needed, and a string in dftables.c that was longer than standard compilers are
1950    required to support.
1951    
1952    2. Compiling with Sun's compiler found a few more places where the code could
1953    be tidied up in order to avoid warnings.
1954    
1955    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
1956    first of these names is deprecated in the latest Autoconf in favour of the name
1957    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
1958    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
1959    analogy I have changed it to CFLAGS_FOR_BUILD.
1960    
1961    4. Added -no-undefined to the linking command in the Makefile, because this is
1962    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
1963    linking step for the pcreposix library.
1964    
1965    5. PCRE was failing to diagnose the case of two named groups with the same
1966    name.
1967    
1968    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
1969    literal character that is needed in the subject for a match, and scans along to
1970    ensure that it is present before embarking on the full matching process. This
1971    saves time in cases of nested unlimited repeats that are never going to match.
1972    Problem: the scan can take a lot of time if the subject is very long (e.g.
1973    megabytes), thus penalizing straightforward matches. It is now done only if the
1974    amount of subject to be scanned is less than 1000 bytes.
1975    
1976    7. A lesser problem with the same optimization is that it was recording the
1977    first character of an anchored pattern as "needed", thus provoking a search
1978    right along the subject, even when the first match of the pattern was going to
1979    fail. The "needed" character is now not set for anchored patterns, unless it
1980    follows something in the pattern that is of non-fixed length. Thus, it still
1981    fulfils its original purpose of finding quick non-matches in cases of nested
1982    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
1983    
1984    
1985    Version 4.0 17-Feb-03
1986    ---------------------
1987    
1988    1. If a comment in an extended regex that started immediately after a meta-item
1989    extended to the end of string, PCRE compiled incorrect data. This could lead to
1990    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
1991    
1992    2. Moved to autoconf 2.53 and libtool 1.4.2.
1993    
1994    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
1995    the special perltest8 script is no longer needed - all the tests can be run
1996    from a single perltest script.
1997    
1998    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
1999    by \s. It has now been removed in PCRE. This means it isn't recognized as
2000    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2001    class [:space:] *does* include VT, thereby creating a mess.
2002    
2003    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2004    space and tab.
2005    
2006    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2007    its new features into the main test script, reducing the number of scripts.
2008    
2009    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2010    were backward compatible, and made the (?i) apply to the whole pattern, as if
2011    /i were given. Now it behaves more logically, and applies the option setting
2012    only to what follows. PCRE has been changed to follow suit. However, if it
2013    finds options settings right at the start of the pattern, it extracts them into
2014    the global options, as before. Thus, they show up in the info data.
2015    
2016    8. Added support for the \Q...\E escape sequence. Characters in between are
2017    treated as literals. This is slightly different from Perl in that $ and @ are
2018    also handled as literals inside the quotes. In Perl, they will cause variable
2019    interpolation. Note the following examples:
2020    
2021        Pattern            PCRE matches      Perl matches
2022    
2023        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2024        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2025        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2026    
2027    For compatibility with Perl, \Q...\E sequences are recognized inside character
2028    classes as well as outside them.
2029    
2030    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2031    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2032    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2033    signed/unsigned warnings.
2034    
2035    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2036    option for pcretest, so I've replaced it by a simple function that does just
2037    that job.
2038    
2039    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2040    "pcregrep -".
2041    
2042    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2043    Java package. This provides some syntactic sugar for simple cases of what my
2044    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2045    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2046    item, you can use this simplified notation. Note that only makes sense with
2047    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2048    greediness, whatever the setting of the PCRE_UNGREEDY option.
2049    
2050    13. A change of greediness default within a pattern was not taking effect at
2051    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2052    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2053    was abstracted outside.
2054    
2055    14. PCRE now supports the \G assertion. It is true when the current matching
2056    position is at the start point of the match. This differs from \A when the
2057    starting offset is non-zero. Used with the /g option of pcretest (or similar
2058    code), it works in the same way as it does for Perl's /g option. If all
2059    alternatives of a regex begin with \G, the expression is anchored to the start
2060    match position, and the "anchored" flag is set in the compiled expression.
2061    
2062    15. Some bugs concerning the handling of certain option changes within patterns
2063    have been fixed. These applied to options other than (?ims). For example,
2064    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2065    been the other way round. Some of this was related to change 7 above.
2066    
2067    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2068    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2069    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2070    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2071    
2072    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2073    mode. Unlike ".", it always matches newline, whatever the setting of
2074    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2075    assertions. Perl allows it, but it doesn't (in general) work because it can't
2076    calculate the length of the lookbehind. At least, that's the case for Perl
2077    5.8.0 - I've been told they are going to document that it doesn't work in
2078    future.
2079    
2080    18. Added an error diagnosis for escapes that PCRE does not support: these are
2081    \L, \l, \N, \P, \p, \U, \u, and \X.
2082    
2083    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2084    reading past the end of the pattern in cases such as /[abcd/.
2085    
2086    20. PCRE was getting more memory than necessary for patterns with classes that
2087    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2088    
2089    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2090    compiling PCRE for use with Virtual Pascal.
2091    
2092    22. Small fix to the Makefile to make it work properly if the build is done
2093    outside the source tree.
2094    
2095    23. Added a new extension: a condition to go with recursion. If a conditional
2096    subpattern starts with (?(R) the "true" branch is used if recursion has
2097    happened, whereas the "false" branch is used only at the top level.
2098    
2099    24. When there was a very long string of literal characters (over 255 bytes
2100    without UTF support, over 250 bytes with UTF support), the computation of how
2101    much memory was required could be incorrect, leading to segfaults or other
2102    strange effects.
2103    
2104    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2105    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2106    there was a subsequent back reference to those brackets. This meant that, for
2107    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2108    possible to check for precisely this case. All we can do is abandon the
2109    optimization if .* occurs inside capturing brackets when there are any back
2110    references whatsoever. (See below for a better fix that came later.)
2111    
2112    26. The handling of the optimization for finding the first character of a
2113    non-anchored pattern, and for finding a character that is required later in the
2114    match were failing in some cases. This didn't break the matching; it just
2115    failed to optimize when it could. The way this is done has been re-implemented.
2116    
2117    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2118    
2119    28. Added a new feature that provides some of the functionality that Perl
2120    provides with (?{...}). The facility is termed a "callout". The way it is done
2121    in PCRE is for the caller to provide an optional function, by setting
2122    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2123    global variable. By default it is unset, which disables all calling out. To get
2124    the function called, the regex must include (?C) at appropriate points. This
2125    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2126    This provides a means of identifying different callout points. When PCRE
2127    reaches such a point in the regex, if pcre_callout has been set, the external
2128    function is called. It is provided with data in a structure called
2129    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2130    matching continues; if it returns a non-zero value, the match at the current
2131    point fails. However, backtracking will occur if possible. [This was changed
2132    later and other features added - see item 49 below.]
2133    
2134    29. pcretest is upgraded to test the callout functionality. It provides a
2135    callout function that displays information. By default, it shows the start of
2136    the match and the current position in the text. There are some new data escapes
2137    to vary what happens:
2138    
2139        \C+         in addition, show current contents of captured substrings
2140        \C-         do not supply a callout function
2141        \C!n        return 1 when callout number n is reached
2142        \C!n!m      return 1 when callout number n is reached for the mth time
2143    
2144    30. If pcregrep was called with the -l option and just a single file name, it
2145    output "<stdin>" if a match was found, instead of the file name.
2146    
2147    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2148    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2149    pcre_exec(). This saves a malloc/free per call. The default value of
2150    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2151    when configuring.
2152    
2153    32. The default maximum size of a compiled pattern is 64K. There have been a
2154    few cases of people hitting this limit. The code now uses macros to handle the
2155    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2156    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2157    configuring. Tests 2 and 5 work only with 2-byte links because they output
2158    debugging information about compiled patterns.
2159    
2160    33. Internal code re-arrangements:
2161    
2162    (a) Moved the debugging function for printing out a compiled regex into
2163        its own source file (printint.c) and used #include to pull it into
2164        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2165        separate copies.
2166    
2167    (b) Defined the list of op-code names for debugging as a macro in
2168        internal.h so that it is next to the definition of the opcodes.
2169    
2170    (c) Defined a table of op-code lengths for simpler skipping along compiled
2171        code. This is again a macro in internal.h so that it is next to the
2172        definition of the opcodes.
2173    
2174    34. Added support for recursive calls to individual subpatterns, along the
2175    lines of Robin Houston's patch (but implemented somewhat differently).
2176    
2177    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2178    allow it to read and process whole directories in Win32. This code was
2179    contributed by Lionel Fourquaux; it has not been tested by me.
2180    
2181    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2182    used to name a group. Names consist of alphanumerics and underscores, and must
2183    be unique. Back references use the syntax (?P=name) and recursive calls use
2184    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2185    numbers. The function pcre_fullinfo() can be used after compilation to extract
2186    a name/number map. There are three relevant calls:
2187    
2188      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2189      PCRE_INFO_NAMECOUNT            yields the number of entries
2190      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2191    
2192    The map is a vector of fixed-size entries. The size of each entry depends on
2193    the length of the longest name used. The first two bytes of each entry are the
2194    group number, most significant byte first. There follows the corresponding
2195    name, zero terminated. The names are in alphabetical order.
2196    
2197    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2198    case instead of 255. Making it the same both with and without UTF-8 support
2199    means that the same test output works with both.
2200    
2201    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2202    calling malloc() with a zero argument.
2203    
2204    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2205    optimization. I've improved things by keeping a bitmap of backreferences with
2206    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2207    fact referenced, the optimization can be applied. It is unlikely that a
2208    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2209    the match to follow \n) will appear inside brackets with a number greater than
2210    31, but if it does, any back reference > 31 suppresses the optimization.
2211    
2212    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2213    of disabling numbered capturing parentheses. Any opening parenthesis that is
2214    not followed by ? behaves as if it were followed by ?: but named parentheses
2215    can still be used for capturing (and they will acquire numbers in the usual
2216    way).
2217    
2218    41. Redesigned the return codes from the match() function into yes/no/error so
2219    that errors can be passed back from deep inside the nested calls. A malloc
2220    failure while inside a recursive subpattern call now causes the
2221    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2222    
2223    42. It is now possible to set a limit on the number of times the match()
2224    function is called in a call to pcre_exec(). This facility makes it possible to
2225    limit the amount of recursion and backtracking, though not in a directly
2226    obvious way, because the match() function is used in a number of different
2227    circumstances. The count starts from zero for each position in the subject
2228    string (for non-anchored patterns). The default limit is, for compatibility, a
2229    large number, namely 10 000 000. You can change this in two ways:
2230    
2231    (a) When configuring PCRE before making, you can use --with-match-limit=n
2232        to set a default value for the compiled library.
2233    
2234    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2235        a different value is set. See 45 below.
2236    
2237    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2238    
2239    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2240    of things that can be changed at compile time. The first argument specifies
2241    what is wanted and the second points to where the information is to be placed.
2242    The current list of available information is:
2243    
2244      PCRE_CONFIG_UTF8
2245    
2246    The output is an integer that is set to one if UTF-8 support is available;
2247    otherwise it is set to zero.
2248    
2249      PCRE_CONFIG_NEWLINE
2250    
2251    The output is an integer that it set to the value of the code that is used for
2252    newline. It is either LF (10) or CR (13).
2253    
2254      PCRE_CONFIG_LINK_SIZE
2255    
2256    The output is an integer that contains the number of bytes used for internal
2257    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2258    
2259      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2260    
2261    The output is an integer that contains the threshold above which the POSIX
2262    interface uses malloc() for output vectors. See item 31 above.
2263    
2264      PCRE_CONFIG_MATCH_LIMIT
2265    
2266    The output is an unsigned integer that contains the default limit of the number
2267    of match() calls in a pcre_exec() execution. See 42 above.
2268    
2269    44. pcretest has been upgraded by the addition of the -C option. This causes it
2270    to extract all the available output from the new pcre_config() function, and to
2271    output it. The program then exits immediately.
2272    
2273    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2274    order to support additional features. One way would have been to define
2275    pcre_exec2() (for example) with extra arguments, but this would not have been
2276    extensible, and would also have required all calls to the original function to
2277    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2278    is used for passing in "extra" data from pcre_study().
2279    
2280    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2281    contains the following fields:
2282    
2283      flags         a bitmap indicating which of the following fields are set
2284      study_data    opaque data from pcre_study()
2285      match_limit   a way of specifying a limit on match() calls for a specific
2286                      call to pcre_exec()
2287      callout_data  data for callouts (see 49 below)
2288    
2289    The flag bits are also defined in pcre.h, and are
2290    
2291      PCRE_EXTRA_STUDY_DATA
2292      PCRE_EXTRA_MATCH_LIMIT
2293      PCRE_EXTRA_CALLOUT_DATA
2294    
2295    The pcre_study() function now returns one of these new pcre_extra blocks, with
2296    the actual study data pointed to by the study_data field, and the
2297    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2298    before. That is, this change is entirely upwards-compatible and requires no
2299    change to existing code.
2300    
2301    If you want to pass in additional data to pcre_exec(), you can either place it
2302    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2303    block.
2304    
2305    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2306    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2307    times with different match limits, until it finds the minimum value needed for
2308    pcre_exec() to complete. The value is then output. This can be instructive; for
2309    most simple matches the number is quite small, but for pathological cases it
2310    gets very large very quickly.
2311    
2312    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2313    returns the size of the data block pointed to by the study_data field in a
2314    pcre_extra block, that is, the value that was passed as the argument to
2315    pcre_malloc() when PCRE was getting memory in which to place the information
2316    created by pcre_study(). The fourth argument should point to a size_t variable.
2317    pcretest has been extended so that this information is shown after a successful
2318    pcre_study() call when information about the compiled regex is being displayed.
2319    
2320    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2321    because what follows is always an absolute path. (Later: it turns out that this
2322    is more than cosmetic for MinGW, because it doesn't like empty path
2323    components.)
2324    
2325    49. Some changes have been made to the callout feature (see 28 above):
2326    
2327    (i)  A callout function now has three choices for what it returns:
2328    
2329           0  =>  success, carry on matching
2330         > 0  =>  failure at this point, but backtrack if possible
2331         < 0  =>  serious error, return this value from pcre_exec()
2332    
2333         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2334         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2335         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2336         use by callout functions. It will never be used by PCRE itself.
2337    
2338    (ii) The pcre_extra structure (see 45 above) has a void * field called
2339         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2340         pcre_callout_block structure has a field of the same name. The contents of
2341         the field passed in the pcre_extra structure are passed to the callout
2342         function in the corresponding field in the callout block. This makes it
2343         easier to use the same callout-containing regex from multiple threads. For
2344         testing, the pcretest program has a new data escape
2345    
2346           \C*n        pass the number n (may be negative) as callout_data
2347    
2348         If the callout function in pcretest receives a non-zero value as
2349         callout_data, it returns that value.
2350    
2351    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2352    there were some redundant $(CFLAGS) in commands that are now specified as
2353    $(LINK), which already includes $(CFLAGS).
2354    
2355    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2356    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2357    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2358    one-byte characters throughout. Note that case-insensitive matching applies
2359    only to characters whose values are less than 256. PCRE doesn't support the
2360    notion of cases for higher-valued characters.
2361    
2362    (i)   A character class whose characters are all within 0-255 is handled as
2363          a bit map, and the map is inverted for negative classes. Previously, a
2364          character > 255 always failed to match such a class; however it should
2365          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2366    
2367    (ii)  A negated character class with a single character < 255 is coded as
2368          "not this character" (OP_NOT). This wasn't working properly when the test
2369          character was multibyte, either singly or repeated.
2370    
2371    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2372          mode, for example: \x{100}{2,3}.
2373    
2374    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2375          singly or repeated) now correctly test multibyte characters. However,
2376          PCRE doesn't recognize any characters with values greater than 255 as
2377          digits, spaces, or word characters. Such characters always match \D, \S,
2378          and \W, and never match \d, \s, or \w.
2379    
2380    (v)   Classes may now contain characters and character ranges with values
2381          greater than 255. For example: [ab\x{100}-\x{400}].
2382    
2383    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2384          PCRE in UTF-8 mode.
2385    
2386    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2387    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2388    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2389    value.)
2390    
2391    53. The single man page has become too large. I have therefore split it up into
2392    a number of separate man pages. These also give rise to individual HTML pages;
2393    these are now put in a separate directory, and there is an index.html page that
2394    lists them all. Some hyperlinking between the pages has been installed.
2395    
2396    54. Added convenience functions for handling named capturing parentheses.
2397    
2398    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2399    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2400    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2401    are faulted.
2402    
2403    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2404    calling configure. These values are used when compiling the dftables.c program
2405    which is run to generate the source of the default character tables. They
2406    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2407    you will need to set these values.
2408    
2409    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2410    
2411    
2412    Version 3.9 02-Jan-02
2413    ---------------------
2414    
2415    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2416    
2417    2. If --disable-static was given, the building process failed when trying to
2418    build pcretest and pcregrep. (For some reason it was using libtool to compile
2419    them, which is not right, as they aren't part of the library.)
2420    
2421    
2422    Version 3.8 18-Dec-01
2423    ---------------------
2424    
2425    1. The experimental UTF-8 code was completely screwed up. It was packing the
2426    bytes in the wrong order. How dumb can you get?
2427    
2428    
2429    Version 3.7 29-Oct-01
2430    ---------------------
2431    
2432    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2433    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2434    this didn't happen under Solaris 8, where I normally test things.
2435    
2436    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2437    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2438    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2439    this fix an hour or so after the initial 3.7 release.)
2440    
2441    
2442    Version 3.6 23-Oct-01
2443    ---------------------
2444    
2445    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2446    offsets passed as NULL with zero offset count.
2447    
2448    2. The config.guess and config.sub files had not been updated when I moved to
2449    the latest autoconf.
2450    
2451    
2452    Version 3.5 15-Aug-01
2453    ---------------------
2454    
2455    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2456    had been forgotten.
2457    
2458    2. By using declared but undefined structures, we can avoid using "void"
2459    definitions in pcre.h while keeping the internal definitions of the structures
2460    private.
2461    
2462    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2463    user point of view, this means that both static and shared libraries are built
2464    by default, but this can be individually controlled. More of the work of
2465    handling this static/shared cases is now inside libtool instead of PCRE's make
2466    file.
2467    
2468    4. The pcretest utility is now installed along with pcregrep because it is
2469    useful for users (to test regexs) and by doing this, it automatically gets
2470    relinked by libtool. The documentation has been turned into a man page, so
2471    there are now .1, .txt, and .html versions in /doc.
2472    
2473    5. Upgrades to pcregrep:
2474       (i)   Added long-form option names like gnu grep.
2475       (ii)  Added --help to list all options with an explanatory phrase.
2476       (iii) Added -r, --recursive to recurse into sub-directories.
2477       (iv)  Added -f, --file to read patterns from a file.
2478    
2479    6. pcre_exec() was referring to its "code" argument before testing that
2480    argument for NULL (and giving an error if it was NULL).
2481    
2482    7. Upgraded Makefile.in to allow for compiling in a different directory from
2483    the source directory.
2484    
2485    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2486    options bits, the pointer it was passed was to an int instead of to an unsigned
2487    long int. This mattered only on 64-bit systems.
2488    
2489    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2490    generated) instead of pcre.in, which it its source. Also made the same change
2491    in several of the .c files.
2492    
2493    10. A new release of gcc defines printf() as a macro, which broke pcretest
2494    because it had an ifdef in the middle of a string argument for printf(). Fixed
2495    by using separate calls to printf().
2496    
2497    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2498    script, to force use of CR or LF instead of \n in the source. On non-Unix
2499    systems, the value can be set in config.h.
2500    
2501    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2502    absolute limit. Changed the text of the error message to make this clear, and
2503    likewise updated the man page.
2504    
2505    13. The limit of 99 on the number of capturing subpatterns has been removed.
2506    The new limit is 65535, which I hope will not be a "real" limit.
2507    
2508    
2509    Version 3.4 22-Aug-00
2510    ---------------------
2511    
2512    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2513    
2514    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2515    
2516    
2517    Version 3.3 01-Aug-00
2518    ---------------------
2519    
2520    1. If an octal character was given, but the value was greater than \377, it
2521    was not getting masked to the least significant bits, as documented. This could
2522    lead to crashes in some systems.
2523    
2524    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2525    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2526    
2527    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2528    These just pass their arguments on to (pcre_free)(), but they are provided
2529    because some uses of PCRE bind it to non-C systems that can call its functions,
2530    but cannot call free() or pcre_free() directly.
2531    
2532    4. Add "make test" as a synonym for "make check". Corrected some comments in
2533    the Makefile.
2534    
2535    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2536    Makefile.
2537    
2538    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2539    command called pgrep for grepping around the active processes.
2540    
2541    7. Added the beginnings of support for UTF-8 character strings.
2542    
2543    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2544    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2545    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2546    out for the ar command.)
2547    
2548    
2549    Version 3.2 12-May-00
2550    ---------------------
2551    
2552    This is purely a bug fixing release.
2553    
2554    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2555    of ZA. This was just one example of several cases that could provoke this bug,
2556    which was introduced by change 9 of version 2.00. The code for breaking
2557    infinite loops after an iteration that matches an empty string was't working
2558    correctly.
2559    
2560    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2561    when matched against abbab (for example). After matching an empty string, it
2562    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2563    caused it to match further down the string than it should.
2564    
2565    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2566    was there because it doesn't seem to be needed, and it causes trouble on some
2567    systems, as it is not a Standard C header. It has been removed.
2568    
2569    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2570    were reported on the Macintosh. The changes were from
2571    
2572      while ((c = *(++ptr)) != 0 && c != '\n');
2573    to
2574      while ((c = *(++ptr)) != 0 && c != '\n') ;
2575    
2576    Totally extraordinary, but if that's what it takes...
2577    
2578    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2579    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2580    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2581    assumes the way PCRE uses memmove() (always moving upwards).
2582    
2583    6. PCRE is being used in one environment where strchr() is not available. There
2584    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2585    faster code anyway.
2586    
2587    
2588    Version 3.1 09-Feb-00
2589    ---------------------
2590    
2591    The only change in this release is the fixing of some bugs in Makefile.in for
2592    the "install" target:
2593    
2594    (1) It was failing to install pcreposix.h.
2595    
2596    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2597    
2598    
2599    Version 3.0 01-Feb-00
2600    ---------------------
2601    
2602    1. Add support for the /+ modifier to perltest (to output $` like it does in
2603    pcretest).
2604    
2605    2. Add support for the /g modifier to perltest.
2606    
2607    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2608    matches null strings.
2609    
2610    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2611    pattern. Perl treats empty patterns specially - it reuses the most recent
2612    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2613    effect.
2614    
2615    5. The POSIX interface was broken in that it was just handing over the POSIX
2616    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2617    required a bigger vector, with some working space on the end. This means that
2618    the POSIX wrapper now has to get and free some memory, and copy the results.
2619    
2620    6. Added some simple autoconf support, placing the test data and the
2621    documentation in separate directories, re-organizing some of the
2622    information files, and making it build pcre-config (a GNU standard). Also added
2623    libtool support for building PCRE as a shared library, which is now the
2624    default.
2625    
2626    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2627    09 are not valid octal constants. Single digits will be used for minor values
2628    less than 10.
2629    
2630    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2631    existing programs that set these in the POSIX interface can use PCRE without
2632    modification.
2633    
2634    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2635    return all that pcre_info() returns, plus additional data. The pcre_info()
2636    function is retained for compatibility, but is considered to be obsolete.
2637    
2638    10. Added experimental recursion feature (?R) to handle one common case that
2639    Perl 5.6 will be able to do with (?p{...}).
2640    
2641    11. Added support for POSIX character classes like [:alpha:], which Perl is
2642    adopting.
2643    
2644    
2645    Version 2.08 31-Aug-99
2646    ----------------------
2647    
2648    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2649    trying to match at the startoffset position, but instead was moving forward to
2650    the next newline as if a previous match had failed.
2651    
2652    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2653    and could get into a loop if a null string was matched other than at the start
2654    of the subject.
2655    
2656    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2657    be distinguished at compile time, and for completeness also added PCRE_DATE.
2658    
2659    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2660    in GnuWin32 environments.
2661    
2662    
2663    Version 2.07 29-Jul-99
2664    ----------------------
2665    
2666    1. The documentation is now supplied in plain text form and HTML as well as in
2667    the form of man page sources.
2668    
2669    2. C++ compilers don't like assigning (void *) values to other pointer types.
2670    In particular this affects malloc(). Although there is no problem in Standard
2671    C, I've put in casts to keep C++ compilers happy.
2672    
2673    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2674    should be (const char *).
2675    
2676    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2677    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2678    However, I haven't made this a standard facility. The documentation doesn't
2679    mention it, and the Makefile doesn't support it.
2680    
2681    5. The Makefile now contains an "install" target, with editable destinations at
2682    the top of the file. The pcretest program is not installed.
2683    
2684    6. pgrep -V now gives the PCRE version number and date.
2685    
2686    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2687    causing the entire string to be ignored, instead of just the last character.
2688    
2689    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2690    non-matching string, it can take a very, very long time, even for strings of
2691    quite modest length, because of the nested recursion. PCRE now does better in
2692    some of these cases. It does this by remembering the last required literal
2693    character in the pattern, and pre-searching the subject to ensure it is present
2694    before running the real match. In other words, it applies a heuristic to detect
2695    some types of certain failure quickly, and in the above example, if presented
2696    with a string that has no trailing " it gives "no match" very quickly.
2697    
2698    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2699    other alternatives are tried instead.
2700    
2701    
2702    Version 2.06 09-Jun-99
2703    ----------------------
2704    
2705    1. Change pcretest's output for amount of store used to show just the code
2706    space, because the remainder (the data block) varies in size between 32-bit and
2707    64-bit systems.
2708    
2709    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2710    start matching at. This allows lookbehinds to work when searching for multiple
2711    occurrences in a string.
2712    
2713    3. Added additional options to pcretest for testing multiple occurrences:
2714    
2715       /+   outputs the rest of the string that follows a match
2716       /g   loops for multiple occurrences, using the new startoffset argument
2717       /G   loops for multiple occurrences by passing an incremented pointer
2718    
2719    4. PCRE wasn't doing the "first character" optimization for patterns starting
2720    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2721    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2722    the letter 'x'. On long subject strings, this gives a significant speed-up.
2723    
2724    
2725    Version 2.05 21-Apr-99
2726    ----------------------
2727    
2728    1. Changed the type of magic_number from int to long int so that it works
2729    properly on 16-bit systems.
2730    
2731    2. Fixed a bug which caused patterns starting with .* not to work correctly
2732    when the subject string contained newline characters. PCRE was assuming
2733    anchoring for such patterns in all cases, which is not correct because .* will
2734    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2735    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2736    must be retried after every newline in the subject.
2737    
2738    
2739  Version 2.04 18-Feb-99  Version 2.04 18-Feb-99
2740  ----------------------  ----------------------

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