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

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