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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 244 by ph10, Fri Sep 14 09:14:24 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.4 10-Sep-07
5    ---------------------
6    
7    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
8        means that a class such as [\s] counted as "explicit reference to CR or
9        LF". That isn't really right - the whole point of the change was to try to
10        help when there was an actual mention of one of the two characters. So now
11        the change happens only if \r or \n (or a literal CR or LF) character is
12        encountered.
13    
14    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
15        of both had grown to the point where there were only 3 bits left.
16        Fortunately, there was spare space in the data structure, and so I have
17        moved the internal flags into a new 16-bit field to free up more option
18        bits.
19    
20    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
21        but did not set the internal JCHANGED flag - either of these is enough to
22        control the way the "get" function works - but the PCRE_INFO_JCHANGED
23        facility is supposed to tell if (?J) was ever used, so now (?J) at the
24        start sets both bits.
25    
26    4.  Added options (at build time, compile time, exec time) to change \R from
27        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
28    
29    5.  doc/pcresyntax.html was missing from the distribution.
30    
31    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
32        compatibility, even though it is no longer used.
33    
34    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
35        strtoull to pcrecpp.cc to select the available functions in WIN32 (where
36        different names are used).
37    
38    8.  Changed all #include <config.h> to #include "config.h". There were also
39        some further <pcre.h> cases that I changed to "pcre.h".
40    
41    9.  When pcregrep was used with the --colour option, it missed the line ending
42        sequence off the lines that it output.
43    
44    10. It was pointed out to me that arrays of string pointers cause lots of
45        relocations when a shared library is dynamically loaded. A technique of
46        using a single long string with a table of offsets can drastically reduce
47        these. I have refactored PCRE in four places to do this. The result is
48        dramatic:
49    
50          Originally:                          290
51          After changing UCP table:            187
52          After changing error message table:   43
53          After changing table of "verbs"       36
54          After changing table of Posix names   22
55    
56        Thanks to the folks working on Gregex for glib for this insight.
57    
58    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
59        unicode-properties was also set.
60    
61    
62    Version 7.3 28-Aug-07
63    ---------------------
64    
65     1. In the rejigging of the build system that eventually resulted in 7.1, the
66        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
67        brackets there is not right, since it causes compilers to look for an
68        installed pcre.h, not the version that is in the source that is being
69        compiled (which of course may be different). I have changed it back to:
70    
71          #include "pcre.h"
72    
73        I have a vague recollection that the change was concerned with compiling in
74        different directories, but in the new build system, that is taken care of
75        by the VPATH setting the Makefile.
76    
77     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
78        when the subject happened to end in the byte 0x85 (e.g. if the last
79        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
80        characters but of course it shouldn't be taken as a newline when it is part
81        of another character. The bug was that, for an unlimited repeat of . in
82        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
83        characters when looking for a newline.
84    
85     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
86    
87     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
88        in debug output.
89    
90     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
91        long printing in the pcrecpp unittest when running under MinGW.
92    
93     6. ESC_K was left out of the EBCDIC table.
94    
95     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
96        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
97        limit also applies to "virtual nesting" when a pattern is recursive, and in
98        this case 1000 isn't so big. I have been able to remove this limit at the
99        expense of backing off one optimization in certain circumstances. Normally,
100        when pcre_exec() would call its internal match() function recursively and
101        immediately return the result unconditionally, it uses a "tail recursion"
102        feature to save stack. However, when a subpattern that can match an empty
103        string has an unlimited repetition quantifier, it no longer makes this
104        optimization. That gives it a stack frame in which to save the data for
105        checking that an empty string has been matched. Previously this was taken
106        from the 1000-entry workspace that had been reserved. So now there is no
107        explicit limit, but more stack is used.
108    
109     8. Applied Daniel's patches to solve problems with the import/export magic
110        syntax that is required for Windows, and which was going wrong for the
111        pcreposix and pcrecpp parts of the library. These were overlooked when this
112        problem was solved for the main library.
113    
114     9. There were some crude static tests to avoid integer overflow when computing
115        the size of patterns that contain repeated groups with explicit upper
116        limits. As the maximum quantifier is 65535, the maximum group length was
117        set at 30,000 so that the product of these two numbers did not overflow a
118        32-bit integer. However, it turns out that people want to use groups that
119        are longer than 30,000 bytes (though not repeat them that many times).
120        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
121        made it possible to implement the integer overflow checks in a much more
122        dynamic way, which I have now done. The artificial limitation on group
123        length has been removed - we now have only the limit on the total length of
124        the compiled pattern, which depends on the LINK_SIZE setting.
125    
126    10. Fixed a bug in the documentation for get/copy named substring when
127        duplicate names are permitted. If none of the named substrings are set, the
128        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
129        empty string.
130    
131    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
132        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
133        because the ] is interpreted as the first data character and the
134        terminating ] is not found. PCRE has been made compatible with Perl in this
135        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
136        cause memory overwriting.
137    
138    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
139        string has been matched (to stop an infinite loop). It was not recognizing
140        a conditional subpattern that could match an empty string if that
141        subpattern was within another subpattern. For example, it looped when
142        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
143        condition was not nested. This bug has been fixed.
144    
145    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
146        past the start of the subject in the presence of bytes with the top bit
147        set, for example "\x8aBCD".
148    
149    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
150        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
151    
152    14. Optimized (?!) to (*FAIL).
153    
154    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
155        This restricts code points to be within the range 0 to 0x10FFFF, excluding
156        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
157        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
158        does: it's just the validity check that is more restrictive.
159    
160    16. Inserted checks for integer overflows during escape sequence (backslash)
161        processing, and also fixed erroneous offset values for syntax errors during
162        backslash processing.
163    
164    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
165        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
166    
167    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
168        caused an overrun.
169    
170    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
171        something other than just ASCII characters) inside a group that had an
172        unlimited repeat caused a loop at compile time (while checking to see
173        whether the group could match an empty string).
174    
175    20. Debugging a pattern containing \p or \P could cause a crash. For example,
176        [\P{Any}] did so. (Error in the code for printing property names.)
177    
178    21. An orphan \E inside a character class could cause a crash.
179    
180    22. A repeated capturing bracket such as (A)? could cause a wild memory
181        reference during compilation.
182    
183    23. There are several functions in pcre_compile() that scan along a compiled
184        expression for various reasons (e.g. to see if it's fixed length for look
185        behind). There were bugs in these functions when a repeated \p or \P was
186        present in the pattern. These operators have additional parameters compared
187        with \d, etc, and these were not being taken into account when moving along
188        the compiled data. Specifically:
189    
190        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
191            length.
192    
193        (b) An item such as \pL+ within a repeated group could cause crashes or
194            loops.
195    
196        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
197            "reference to non-existent subpattern" error.
198    
199        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
200    
201    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
202        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
203    
204    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
205    
206    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
207        character were causing crashes (broken optimization).
208    
209    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
210        \p or \P) caused a compile-time loop.
211    
212    28. More problems have arisen in unanchored patterns when CRLF is a valid line
213        break. For example, the unstudied pattern [\r\n]A does not match the string
214        "\r\nA" because change 7.0/46 below moves the current point on by two
215        characters after failing to match at the start. However, the pattern \nA
216        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
217        the same is true. There doesn't seem any very clean way out of this, but
218        what I have chosen to do makes the common cases work: PCRE now takes note
219        of whether there can be an explicit match for \r or \n anywhere in the
220        pattern, and if so, 7.0/46 no longer applies. As part of this change,
221        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
222        pattern has explicit CR or LF references.
223    
224    29. Added (*CR) etc for changing newline setting at start of pattern.
225    
226    
227    Version 7.2 19-Jun-07
228    ---------------------
229    
230     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
231        which is apparently normally available under Windows.
232    
233     2. Re-jig the pcregrep tests with different newline settings in an attempt
234        to make them independent of the local environment's newline setting.
235    
236     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
237    
238     4. Some of the "internals" tests were previously cut out when the link size
239        was not 2, because the output contained actual offsets. The recent new
240        "Z" feature of pcretest means that these can be cut out, making the tests
241        usable with all link sizes.
242    
243     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
244        stack recursion. This gives a massive performance boost under BSD, but just
245        a small improvement under Linux. However, it saves one field in the frame
246        in all cases.
247    
248     6. Added more features from the forthcoming Perl 5.10:
249    
250        (a) (?-n) (where n is a string of digits) is a relative subroutine or
251            recursion call. It refers to the nth most recently opened parentheses.
252    
253        (b) (?+n) is also a relative subroutine call; it refers to the nth next
254            to be opened parentheses.
255    
256        (c) Conditions that refer to capturing parentheses can be specified
257            relatively, for example, (?(-2)... or (?(+3)...
258    
259        (d) \K resets the start of the current match so that everything before
260            is not part of it.
261    
262        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
263    
264        (f) \g{name} is another synonym - part of Perl 5.10's unification of
265            reference syntax.
266    
267        (g) (?| introduces a group in which the numbering of parentheses in each
268            alternative starts with the same number.
269    
270        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
271    
272     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
273        PCRE_INFO_JCHANGED.
274    
275     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
276        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
277        for detecting groups that can match an empty string.
278    
279     9. A pattern with a very large number of alternatives (more than several
280        hundred) was running out of internal workspace during the pre-compile
281        phase, where pcre_compile() figures out how much memory will be needed. A
282        bit of new cunning has reduced the workspace needed for groups with
283        alternatives. The 1000-alternative test pattern now uses 12 bytes of
284        workspace instead of running out of the 4096 that are available.
285    
286    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
287    
288    11. Applied patch from Google to remove an optimization that didn't quite work.
289        The report of the bug said:
290    
291          pcrecpp::RE("a*").FullMatch("aaa") matches, while
292          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
293          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
294    
295    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
296        it matched the wrong number of bytes.
297    
298    
299    Version 7.1 24-Apr-07
300    ---------------------
301    
302     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
303        that is more "standard", making use of automake and other Autotools. There
304        is some re-arrangement of the files and adjustment of comments consequent
305        on this.
306    
307     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
308        for recursive directory scanning broke on some systems because the files
309        are not scanned in any specific order and on different systems the order
310        was different. A call to "sort" has been inserted into RunGrepTest for the
311        approprate test as a short-term fix. In the longer term there may be an
312        alternative.
313    
314     3. I had an email from Eric Raymond about problems translating some of PCRE's
315        man pages to HTML (despite the fact that I distribute HTML pages, some
316        people do their own conversions for various reasons). The problems
317        concerned the use of low-level troff macros .br and .in. I have therefore
318        removed all such uses from the man pages (some were redundant, some could
319        be replaced by .nf/.fi pairs). The 132html script that I use to generate
320        HTML has been updated to handle .nf/.fi and to complain if it encounters
321        .br or .in.
322    
323     4. Updated comments in configure.ac that get placed in config.h.in and also
324        arranged for config.h to be included in the distribution, with the name
325        config.h.generic, for the benefit of those who have to compile without
326        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
327    
328     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
329        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
330        makevp.bat for the current PCRE, using the additional files
331        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
332    
333     6. A Windows user reported a minor discrepancy with test 2, which turned out
334        to be caused by a trailing space on an input line that had got lost in his
335        copy. The trailing space was an accident, so I've just removed it.
336    
337     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
338        that is needed.
339    
340     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
341        as "const" (a) because they are and (b) because it helps the PHP
342        maintainers who have recently made a script to detect big data structures
343        in the php code that should be moved to the .rodata section. I remembered
344        to update Builducptable as well, so it won't revert if ucptable.h is ever
345        re-created.
346    
347     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
348        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
349        order to be able to cut out the UTF-8 tables in the latter when UTF-8
350        support is not required. This saves 1.5-2K of code, which is important in
351        some applications.
352    
353        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
354        so as not to refer to the tables, even though these functions will never be
355        called when UTF-8 support is disabled. Otherwise there are problems with a
356        shared library.
357    
358    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
359    
360        (a) It was defining its arguments as char * instead of void *.
361    
362        (b) It was assuming that all moves were upwards in memory; this was true
363            a long time ago when I wrote it, but is no longer the case.
364    
365        The emulated memove() is provided for those environments that have neither
366        memmove() nor bcopy(). I didn't think anyone used it these days, but that
367        is clearly not the case, as these two bugs were recently reported.
368    
369    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
370        and Detrail to create the HTML documentation, the .txt form of the man
371        pages, and it removes trailing spaces from listed files. It also creates
372        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
373        case, it wraps all the #defines with #ifndefs. This script should be run
374        before "make dist".
375    
376    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
377        with Unicode property support.
378    
379        (a) For a maximizing quantifier, if the two different cases of the
380            character were of different lengths in their UTF-8 codings (there are
381            some cases like this - I found 11), and the matching function had to
382            back up over a mixture of the two cases, it incorrectly assumed they
383            were both the same length.
384    
385        (b) When PCRE was configured to use the heap rather than the stack for
386            recursion during matching, it was not correctly preserving the data for
387            the other case of a UTF-8 character when checking ahead for a match
388            while processing a minimizing repeat. If the check also involved
389            matching a wide character, but failed, corruption could cause an
390            erroneous result when trying to check for a repeat of the original
391            character.
392    
393    13. Some tidying changes to the testing mechanism:
394    
395        (a) The RunTest script now detects the internal link size and whether there
396            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
397            values substituted by "configure". (The RunGrepTest script already did
398            this for UTF-8.) The configure.ac script no longer substitutes the
399            relevant variables.
400    
401        (b) The debugging options /B and /D in pcretest show the compiled bytecode
402            with length and offset values. This means that the output is different
403            for different internal link sizes. Test 2 is skipped for link sizes
404            other than 2 because of this, bypassing the problem. Unfortunately,
405            there was also a test in test 3 (the locale tests) that used /B and
406            failed for link sizes other than 2. Rather than cut the whole test out,
407            I have added a new /Z option to pcretest that replaces the length and
408            offset values with spaces. This is now used to make test 3 independent
409            of link size. (Test 2 will be tidied up later.)
410    
411    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
412        segmentation fault instead of returning the appropriate error message.
413    
414    15. In multiline mode when the newline sequence was set to "any", the pattern
415        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
416        This doesn't seem right; it now treats the CRLF combination as the line
417        ending, and so does not match in that case. It's only a pattern such as ^$
418        that would hit this one: something like ^ABC$ would have failed after \r
419        and then tried again after \r\n.
420    
421    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
422        in an attempt to make files that differ only in their line terminators
423        compare equal. This works on Linux.
424    
425    17. Under certain error circumstances pcregrep might try to free random memory
426        as it exited. This is now fixed, thanks to valgrind.
427    
428    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
429        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
430        was because its rules for how to advance for /g after matching an empty
431        string at the end of a line did not allow for this case. They now check for
432        it specially.
433    
434    20. pcretest is supposed to handle patterns and data of any length, by
435        extending its buffers when necessary. It was getting this wrong when the
436        buffer for a data line had to be extended.
437    
438    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
439        CRLF as a newline sequence.
440    
441    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
442        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
443        I have nevertheless tidied it up.
444    
445    23. Added some casts to kill warnings from HP-UX ia64 compiler.
446    
447    24. Added a man page for pcre-config.
448    
449    
450    Version 7.0 19-Dec-06
451    ---------------------
452    
453     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
454        moving to gcc 4.1.1.
455    
456     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
457        sys/time.h, which is documented as needed for this function. It doesn't
458        seem to matter on Linux, but it showed up on some releases of OS X.
459    
460     3. It seems that there are systems where bytes whose values are greater than
461        127 match isprint() in the "C" locale. The "C" locale should be the
462        default when a C program starts up. In most systems, only ASCII printing
463        characters match isprint(). This difference caused the output from pcretest
464        to vary, making some of the tests fail. I have changed pcretest so that:
465    
466        (a) When it is outputting text in the compiled version of a pattern, bytes
467            other than 32-126 are always shown as hex escapes.
468    
469        (b) When it is outputting text that is a matched part of a subject string,
470            it does the same, unless a different locale has been set for the match
471            (using the /L modifier). In this case, it uses isprint() to decide.
472    
473     4. Fixed a major bug that caused incorrect computation of the amount of memory
474        required for a compiled pattern when options that changed within the
475        pattern affected the logic of the preliminary scan that determines the
476        length. The relevant options are -x, and -i in UTF-8 mode. The result was
477        that the computed length was too small. The symptoms of this bug were
478        either the PCRE error "internal error: code overflow" from pcre_compile(),
479        or a glibc crash with a message such as "pcretest: free(): invalid next
480        size (fast)". Examples of patterns that provoked this bug (shown in
481        pcretest format) are:
482    
483          /(?-x: )/x
484          /(?x)(?-x: \s*#\s*)/
485          /((?i)[\x{c0}])/8
486          /(?i:[\x{c0}])/8
487    
488        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
489        is now done differently.
490    
491     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
492        wrapper classes; (b) implement a new function in the C++ scanner that is
493        more efficient than the old way of doing things because it avoids levels of
494        recursion in the regex matching; (c) add a paragraph to the documentation
495        for the FullMatch() function.
496    
497     6. The escape sequence \n was being treated as whatever was defined as
498        "newline". Not only was this contrary to the documentation, which states
499        that \n is character 10 (hex 0A), but it also went horribly wrong when
500        "newline" was defined as CRLF. This has been fixed.
501    
502     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
503        was being set to -1 for the "end of line" case (supposedly a value that no
504        character can have). Though this value is never used (the check for end of
505        line is "zero bytes in current character"), it caused compiler complaints.
506        I've changed it to 0xffffffff.
507    
508     8. In pcre_version.c, the version string was being built by a sequence of
509        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
510        string (as it is for production releases) called a macro with an empty
511        argument. The C standard says the result of this is undefined. The gcc
512        compiler treats it as an empty string (which was what was wanted) but it is
513        reported that Visual C gives an error. The source has been hacked around to
514        avoid this problem.
515    
516     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
517        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
518        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
519        of them did).
520    
521    10. Originally, pcretest opened its input and output without "b"; then I was
522        told that "b" was needed in some environments, so it was added for release
523        5.0 to both the input and output. (It makes no difference on Unix-like
524        systems.) Later I was told that it is wrong for the input on Windows. I've
525        now abstracted the modes into two macros, to make it easier to fiddle with
526        them, and removed "b" from the input mode under Windows.
527    
528    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
529    
530    12. Added -help and --help to pcretest as an official way of being reminded
531        of the options.
532    
533    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
534        and pcrecpp.cc because they annoy compilers at high warning levels.
535    
536    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
537    
538    15. Fixed an occurrence of == in configure.ac that should have been = (shell
539        scripts are not C programs :-) and which was not noticed because it works
540        on Linux.
541    
542    16. pcretest is supposed to handle any length of pattern and data line (as one
543        line or as a continued sequence of lines) by extending its input buffer if
544        necessary. This feature was broken for very long pattern lines, leading to
545        a string of junk being passed to pcre_compile() if the pattern was longer
546        than about 50K.
547    
548    17. I have done a major re-factoring of the way pcre_compile() computes the
549        amount of memory needed for a compiled pattern. Previously, there was code
550        that made a preliminary scan of the pattern in order to do this. That was
551        OK when PCRE was new, but as the facilities have expanded, it has become
552        harder and harder to keep it in step with the real compile phase, and there
553        have been a number of bugs (see for example, 4 above). I have now found a
554        cunning way of running the real compile function in a "fake" mode that
555        enables it to compute how much memory it would need, while actually only
556        ever using a few hundred bytes of working memory and without too many
557        tests of the mode. This should make future maintenance and development
558        easier. A side effect of this work is that the limit of 200 on the nesting
559        depth of parentheses has been removed (though this was never a serious
560        limitation, I suspect). However, there is a downside: pcre_compile() now
561        runs more slowly than before (30% or more, depending on the pattern). I
562        hope this isn't a big issue. There is no effect on runtime performance.
563    
564    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
565        newline (only possible for the last line of a file) and it was a
566        pattern that set a locale (followed by /Lsomething), pcretest crashed.
567    
568    19. Added additional timing features to pcretest. (1) The -tm option now times
569        matching only, not compiling. (2) Both -t and -tm can be followed, as a
570        separate command line item, by a number that specifies the number of
571        repeats to use when timing. The default is 50000; this gives better
572        precision, but takes uncomfortably long for very large patterns.
573    
574    20. Extended pcre_study() to be more clever in cases where a branch of a
575        subpattern has no definite first character. For example, (a*|b*)[cd] would
576        previously give no result from pcre_study(). Now it recognizes that the
577        first character must be a, b, c, or d.
578    
579    21. There was an incorrect error "recursive call could loop indefinitely" if
580        a subpattern (or the entire pattern) that was being tested for matching an
581        empty string contained only one non-empty item after a nested subpattern.
582        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
583        incorrectly, because the \d was being skipped in the check.
584    
585    22. The pcretest program now has a new pattern option /B and a command line
586        option -b, which is equivalent to adding /B to every pattern. This causes
587        it to show the compiled bytecode, without the additional information that
588        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
589        is the same as /B/I).
590    
591    23. A new optimization is now able automatically to treat some sequences such
592        as a*b as a*+b. More specifically, if something simple (such as a character
593        or a simple class like \d) has an unlimited quantifier, and is followed by
594        something that cannot possibly match the quantified thing, the quantifier
595        is automatically "possessified".
596    
597    24. A recursive reference to a subpattern whose number was greater than 39
598        went wrong under certain circumstances in UTF-8 mode. This bug could also
599        have affected the operation of pcre_study().
600    
601    25. Realized that a little bit of performance could be had by replacing
602        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
603    
604    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
605    
606    27. Possessive quantifiers such as a++ were previously implemented by turning
607        them into atomic groups such as ($>a+). Now they have their own opcodes,
608        which improves performance. This includes the automatically created ones
609        from 23 above.
610    
611    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
612        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
613        the first matched character to be a colon. This applied both to named and
614        numbered groups.
615    
616    29. The ucpinternal.h header file was missing its idempotency #ifdef.
617    
618    30. I was sent a "project" file called libpcre.a.dev which I understand makes
619        building PCRE on Windows easier, so I have included it in the distribution.
620    
621    31. There is now a check in pcretest against a ridiculously large number being
622        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
623        loop, the loop is abandoned.
624    
625    32. Forward references to subpatterns in conditions such as (?(2)...) where
626        subpattern 2 is defined later cause pcre_compile() to search forwards in
627        the pattern for the relevant set of parentheses. This search went wrong
628        when there were unescaped parentheses in a character class, parentheses
629        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
630    
631    33. "Subroutine" calls and backreferences were previously restricted to
632        referencing subpatterns earlier in the regex. This restriction has now
633        been removed.
634    
635    34. Added a number of extra features that are going to be in Perl 5.10. On the
636        whole, these are just syntactic alternatives for features that PCRE had
637        previously implemented using the Python syntax or my own invention. The
638        other formats are all retained for compatibility.
639    
640        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
641            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
642            also .NET compatible.
643    
644        (b) A recursion or subroutine call to a named group can now be defined as
645            (?&name) as well as (?P>name).
646    
647        (c) A backreference to a named group can now be defined as \k<name> or
648            \k'name' as well as (?P=name). The new forms, as well as being in Perl
649            5.10, are also .NET compatible.
650    
651        (d) A conditional reference to a named group can now use the syntax
652            (?(<name>) or (?('name') as well as (?(name).
653    
654        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
655            groups (named and numbered) that are never evaluated inline, but can be
656            called as "subroutines" from elsewhere. In effect, the DEFINE condition
657            is always false. There may be only one alternative in such a group.
658    
659        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
660            as the simple (?(R). The condition is true only if the most recent
661            recursion is that of the given number or name. It does not search out
662            through the entire recursion stack.
663    
664        (g) The escape \gN or \g{N} has been added, where N is a positive or
665            negative number, specifying an absolute or relative reference.
666    
667    35. Tidied to get rid of some further signed/unsigned compiler warnings and
668        some "unreachable code" warnings.
669    
670    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
671        things, this adds five new scripts.
672    
673    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
674        There were also incompatibilities regarding the handling of \Q..\E inside
675        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
676        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
677    
678    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
679        matches an empty string, and forcibly breaks the loop. There were bugs in
680        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
681        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
682        separate and independent bugs (that affected different cases) have been
683        fixed.
684    
685    39. Refactored the code to abolish the use of different opcodes for small
686        capturing bracket numbers. This is a tidy that I avoided doing when I
687        removed the limit on the number of capturing brackets for 3.5 back in 2001.
688        The new approach is not only tidier, it makes it possible to reduce the
689        memory needed to fix the previous bug (38).
690    
691    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
692        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
693        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
694        mode.
695    
696    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
697        report.
698    
699    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
700        copy construction and assignment in the C++ wrapper.
701    
702    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
703        couple of bugs that could have given wrong results in the "--newline=crlf"
704        case.
705    
706    44. Added a number of casts and did some reorganization of signed/unsigned int
707        variables following suggestions from Dair Grant. Also renamed the variable
708        "this" as "item" because it is a C++ keyword.
709    
710    45. Arranged for dftables to add
711    
712          #include "pcre_internal.h"
713    
714        to pcre_chartables.c because without it, gcc 4.x may remove the array
715        definition from the final binary if PCRE is built into a static library and
716        dead code stripping is activated.
717    
718    46. For an unanchored pattern, if a match attempt fails at the start of a
719        newline sequence, and the newline setting is CRLF or ANY, and the next two
720        characters are CRLF, advance by two characters instead of one.
721    
722    
723    Version 6.7 04-Jul-06
724    ---------------------
725    
726     1. In order to handle tests when input lines are enormously long, pcretest has
727        been re-factored so that it automatically extends its buffers when
728        necessary. The code is crude, but this _is_ just a test program. The
729        default size has been increased from 32K to 50K.
730    
731     2. The code in pcre_study() was using the value of the re argument before
732        testing it for NULL. (Of course, in any sensible call of the function, it
733        won't be NULL.)
734    
735     3. The memmove() emulation function in pcre_internal.h, which is used on
736        systems that lack both memmove() and bcopy() - that is, hardly ever -
737        was missing a "static" storage class specifier.
738    
739     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
740        containing an extended class (one that cannot be represented by a bitmap
741        because it contains high-valued characters or Unicode property items, e.g.
742        [\pZ]). Almost always one would set UTF-8 mode when processing such a
743        pattern, but PCRE should not loop if you do not (it no longer does).
744        [Detail: two cases were found: (a) a repeated subpattern containing an
745        extended class; (b) a recursive reference to a subpattern that followed a
746        previous extended class. It wasn't skipping over the extended class
747        correctly when UTF-8 mode was not set.]
748    
749     5. A negated single-character class was not being recognized as fixed-length
750        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
751        compile error "lookbehind assertion is not fixed length".
752    
753     6. The RunPerlTest auxiliary script was showing an unexpected difference
754        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
755        write a Perl script that can interpret lines of an input file either as
756        byte characters or as UTF-8, which is what "perltest" was being required to
757        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
758        can't do is switch easily at run time between having the "use utf8;" pragma
759        or not. In the end, I fudged it by using the RunPerlTest script to insert
760        "use utf8;" explicitly for the UTF-8 tests.
761    
762     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
763        the end of the subject string, contrary to the documentation and to what
764        Perl does. This was true of both matching functions. Now it matches only at
765        the start of the subject and immediately after *internal* newlines.
766    
767     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
768        a pointer to an int instead of a pointer to an unsigned long int. This
769        caused problems on 64-bit systems.
770    
771     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
772        instance of the 'standard' template library not being so standard".
773    
774    10. There was no check on the number of named subpatterns nor the maximum
775        length of a subpattern name. The product of these values is used to compute
776        the size of the memory block for a compiled pattern. By supplying a very
777        long subpattern name and a large number of named subpatterns, the size
778        computation could be caused to overflow. This is now prevented by limiting
779        the length of names to 32 characters, and the number of named subpatterns
780        to 10,000.
781    
782    11. Subpatterns that are repeated with specific counts have to be replicated in
783        the compiled pattern. The size of memory for this was computed from the
784        length of the subpattern and the repeat count. The latter is limited to
785        65535, but there was no limit on the former, meaning that integer overflow
786        could in principle occur. The compiled length of a repeated subpattern is
787        now limited to 30,000 bytes in order to prevent this.
788    
789    12. Added the optional facility to have named substrings with the same name.
790    
791    13. Added the ability to use a named substring as a condition, using the
792        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
793        are numbers (not recommended). Forward references are permitted.
794    
795    14. Added forward references in named backreferences (if you see what I mean).
796    
797    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
798        pattern could run off the end of the subject. For example, the pattern
799        "(?s)(.{1,5})"8 did this with the subject "ab".
800    
801    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
802        PCRE_CASELESS was set when matching characters that were quantified with ?
803        or *.
804    
805    17. A character class other than a single negated character that had a minimum
806        but no maximum quantifier - for example [ab]{6,} - was not handled
807        correctly by pce_dfa_exec(). It would match only one character.
808    
809    18. A valid (though odd) pattern that looked like a POSIX character
810        class but used an invalid character after [ (for example [[,abc,]]) caused
811        pcre_compile() to give the error "Failed: internal error: code overflow" or
812        in some cases to crash with a glibc free() error. This could even happen if
813        the pattern terminated after [[ but there just happened to be a sequence of
814        letters, a binary zero, and a closing ] in the memory that followed.
815    
816    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
817        over the years. Originally (before any Unicode support), just the bottom 8
818        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
819        output from "man perlunicode" includes this:
820    
821          The regular expression compiler produces polymorphic opcodes.  That
822          is, the pattern adapts to the data and automatically switches to
823          the Unicode character scheme when presented with Unicode data--or
824          instead uses a traditional byte scheme when presented with byte
825          data.
826    
827        Sadly, a wide octal escape does not cause a switch, and in a string with
828        no other multibyte characters, these octal escapes are treated as before.
829        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
830        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
831        Unicode string.
832    
833        I have not perpetrated such confusion in PCRE. Up till now, it took just
834        the bottom 8 bits, as in old Perl. I have now made octal escapes with
835        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
836        translate to the appropriate multibyte character.
837    
838    29. Applied some refactoring to reduce the number of warnings from Microsoft
839        and Borland compilers. This has included removing the fudge introduced
840        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
841        a warning about an unused variable.
842    
843    21. PCRE has not included VT (character 0x0b) in the set of whitespace
844        characters since release 4.0, because Perl (from release 5.004) does not.
845        [Or at least, is documented not to: some releases seem to be in conflict
846        with the documentation.] However, when a pattern was studied with
847        pcre_study() and all its branches started with \s, PCRE still included VT
848        as a possible starting character. Of course, this did no harm; it just
849        caused an unnecessary match attempt.
850    
851    22. Removed a now-redundant internal flag bit that recorded the fact that case
852        dependency changed within the pattern. This was once needed for "required
853        byte" processing, but is no longer used. This recovers a now-scarce options
854        bit. Also moved the least significant internal flag bit to the most-
855        significant bit of the word, which was not previously used (hangover from
856        the days when it was an int rather than a uint) to free up another bit for
857        the future.
858    
859    23. Added support for CRLF line endings as well as CR and LF. As well as the
860        default being selectable at build time, it can now be changed at runtime
861        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
862        specify that it is scanning data with non-default line endings.
863    
864    24. Changed the definition of CXXLINK to make it agree with the definition of
865        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
866    
867    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
868        recursions. This makes a big different to stack usage for some patterns.
869    
870    26. If a subpattern containing a named recursion or subroutine reference such
871        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
872        the space required for the compiled pattern went wrong and gave too small a
873        value. Depending on the environment, this could lead to "Failed: internal
874        error: code overflow at offset 49" or "glibc detected double free or
875        corruption" errors.
876    
877    27. Applied patches from Google (a) to support the new newline modes and (b) to
878        advance over multibyte UTF-8 characters in GlobalReplace.
879    
880    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
881        difference for some implementation of PCRE in some Windows version.
882    
883    29. Added some extra testing facilities to pcretest:
884    
885        \q<number>   in a data line sets the "match limit" value
886        \Q<number>   in a data line sets the "match recursion limt" value
887        -S <number>  sets the stack size, where <number> is in megabytes
888    
889        The -S option isn't available for Windows.
890    
891    
892    Version 6.6 06-Feb-06
893    ---------------------
894    
895     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
896        in pcreposix.h. I have copied the definition from pcre.h.
897    
898     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
899        because pcre.h is no longer a built file.
900    
901     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
902        not normally included in the compiled code.
903    
904    
905    Version 6.5 01-Feb-06
906    ---------------------
907    
908     1. When using the partial match feature with pcre_dfa_exec(), it was not
909        anchoring the second and subsequent partial matches at the new starting
910        point. This could lead to incorrect results. For example, with the pattern
911        /1234/, partially matching against "123" and then "a4" gave a match.
912    
913     2. Changes to pcregrep:
914    
915        (a) All non-match returns from pcre_exec() were being treated as failures
916            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
917            error message is output. Some extra information is given for the
918            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
919            probably the only errors that are likely to be caused by users (by
920            specifying a regex that has nested indefinite repeats, for instance).
921            If there are more than 20 of these errors, pcregrep is abandoned.
922    
923        (b) A binary zero was treated as data while matching, but terminated the
924            output line if it was written out. This has been fixed: binary zeroes
925            are now no different to any other data bytes.
926    
927        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
928            used to set a locale for matching. The --locale=xxxx long option has
929            been added (no short equivalent) to specify a locale explicitly on the
930            pcregrep command, overriding the environment variables.
931    
932        (d) When -B was used with -n, some line numbers in the output were one less
933            than they should have been.
934    
935        (e) Added the -o (--only-matching) option.
936    
937        (f) If -A or -C was used with -c (count only), some lines of context were
938            accidentally printed for the final match.
939    
940        (g) Added the -H (--with-filename) option.
941    
942        (h) The combination of options -rh failed to suppress file names for files
943            that were found from directory arguments.
944    
945        (i) Added the -D (--devices) and -d (--directories) options.
946    
947        (j) Added the -F (--fixed-strings) option.
948    
949        (k) Allow "-" to be used as a file name for -f as well as for a data file.
950    
951        (l) Added the --colo(u)r option.
952    
953        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
954            is not present by default.
955    
956     3. A nasty bug was discovered in the handling of recursive patterns, that is,
957        items such as (?R) or (?1), when the recursion could match a number of
958        alternatives. If it matched one of the alternatives, but subsequently,
959        outside the recursion, there was a failure, the code tried to back up into
960        the recursion. However, because of the way PCRE is implemented, this is not
961        possible, and the result was an incorrect result from the match.
962    
963        In order to prevent this happening, the specification of recursion has
964        been changed so that all such subpatterns are automatically treated as
965        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
966    
967     4. I had overlooked the fact that, in some locales, there are characters for
968        which isalpha() is true but neither isupper() nor islower() are true. In
969        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
970        and ordfeminine) are like this. This affected the treatment of \w and \W
971        when they appeared in character classes, but not when they appeared outside
972        a character class. The bit map for "word" characters is now created
973        separately from the results of isalnum() instead of just taking it from the
974        upper, lower, and digit maps. (Plus the underscore character, of course.)
975    
976     5. The above bug also affected the handling of POSIX character classes such as
977        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
978        permanent tables. Instead, the bit maps for such a class were previously
979        created as the appropriate unions of the upper, lower, and digit bitmaps.
980        Now they are created by subtraction from the [[:word:]] class, which has
981        its own bitmap.
982    
983     6. The [[:blank:]] character class matches horizontal, but not vertical space.
984        It is created by subtracting the vertical space characters (\x09, \x0a,
985        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
986        subtraction was done in the overall bitmap for a character class, meaning
987        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
988        be recognized. This bug has been fixed.
989    
990     7. Patches from the folks at Google:
991    
992          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
993          real life, but is still worth protecting against".
994    
995          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
996          regular expressions".
997    
998          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
999          have it.
1000    
1001          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1002          "configure" and the latter not, in order to fix a problem somebody had
1003          with compiling the Arg class on HP-UX.
1004    
1005          (e) Improve the error-handling of the C++ wrapper a little bit.
1006    
1007          (f) New tests for checking recursion limiting.
1008    
1009     8. The pcre_memmove() function, which is used only if the environment does not
1010        have a standard memmove() function (and is therefore rarely compiled),
1011        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1012        returning a result (though PCRE never actually uses the result).
1013    
1014     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1015        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1016        returned instead of calling malloc() with an overflowing number that would
1017        most likely cause subsequent chaos.
1018    
1019    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1020    
1021    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1022        with this option is matched, the nmatch and pmatch options of regexec() are
1023        ignored.
1024    
1025    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1026        provided in case anyone wants to the the POSIX interface with UTF-8
1027        strings.
1028    
1029    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1030        C++ linking (needed for some HP-UX environments).
1031    
1032    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1033        (unused parameter) and in the pcre_printint() function (omitted "default"
1034        switch label when the default is to do nothing).
1035    
1036    15. Added some code to make it possible, when PCRE is compiled as a C++
1037        library, to replace subject pointers for pcre_exec() with a smart pointer
1038        class, thus making it possible to process discontinuous strings.
1039    
1040    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1041        much the same function. They were added by different people who were trying
1042        to make PCRE easy to compile on non-Unix systems. It has been suggested
1043        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1044        for compiling on Windows systems. I have therefore replaced it with
1045        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1046        defaults to "extern" for C or "extern C" for C++, which works fine on
1047        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1048        SCOPE with something explicit in config.h. In addition:
1049    
1050        (a) pcreposix.h still had just "extern" instead of either of these macros;
1051            I have replaced it with PCRE_DATA_SCOPE.
1052    
1053        (b) Functions such as _pcre_xclass(), which are internal to the library,
1054            but external in the C sense, all had PCRE_EXPORT in their definitions.
1055            This is apparently wrong for the Windows case, so I have removed it.
1056            (It makes no difference on Unix-like systems.)
1057    
1058    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1059        of recursive calls to match(). This is different to MATCH_LIMIT because
1060        that limits the total number of calls to match(), not all of which increase
1061        the depth of recursion. Limiting the recursion depth limits the amount of
1062        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1063        when PCRE is compiled, and changed at run time. A patch from Google adds
1064        this functionality to the C++ interface.
1065    
1066    18. Changes to the handling of Unicode character properties:
1067    
1068        (a) Updated the table to Unicode 4.1.0.
1069    
1070        (b) Recognize characters that are not in the table as "Cn" (undefined).
1071    
1072        (c) I revised the way the table is implemented to a much improved format
1073            which includes recognition of ranges. It now supports the ranges that
1074            are defined in UnicodeData.txt, and it also amalgamates other
1075            characters into ranges. This has reduced the number of entries in the
1076            table from around 16,000 to around 3,000, thus reducing its size
1077            considerably. I realized I did not need to use a tree structure after
1078            all - a binary chop search is just as efficient. Having reduced the
1079            number of entries, I extended their size from 6 bytes to 8 bytes to
1080            allow for more data.
1081    
1082        (d) Added support for Unicode script names via properties such as \p{Han}.
1083    
1084    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1085        matching that character.
1086    
1087    20. When matching a repeated Unicode property with a minimum greater than zero,
1088        (for example \pL{2,}), PCRE could look past the end of the subject if it
1089        reached it while seeking the minimum number of characters. This could
1090        happen only if some of the characters were more than one byte long, because
1091        there is a check for at least the minimum number of bytes.
1092    
1093    21. Refactored the implementation of \p and \P so as to be more general, to
1094        allow for more different types of property in future. This has changed the
1095        compiled form incompatibly. Anybody with saved compiled patterns that use
1096        \p or \P will have to recompile them.
1097    
1098    22. Added "Any" and "L&" to the supported property types.
1099    
1100    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1101        but give a compile time error if the value is greater than 0xff.
1102    
1103    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1104        accidentally not being installed or uninstalled.
1105    
1106    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1107        made were to insert the current release number. This seemed silly, because
1108        it made things harder for people building PCRE on systems that don't run
1109        "configure". I have turned pcre.h into a distributed file, no longer built
1110        by "configure", with the version identification directly included. There is
1111        no longer a pcre.h.in file.
1112    
1113        However, this change necessitated a change to the pcre-config script as
1114        well. It is built from pcre-config.in, and one of the substitutions was the
1115        release number. I have updated configure.ac so that ./configure now finds
1116        the release number by grepping pcre.h.
1117    
1118    26. Added the ability to run the tests under valgrind.
1119    
1120    
1121    Version 6.4 05-Sep-05
1122    ---------------------
1123    
1124     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1125        "--" to be printed when multiple files were scanned, even when none of the
1126        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1127        consider it to be a bug, and have restored the previous behaviour.
1128    
1129     2. A couple of code tidies to get rid of compiler warnings.
1130    
1131     3. The pcretest program used to cheat by referring to symbols in the library
1132        whose names begin with _pcre_. These are internal symbols that are not
1133        really supposed to be visible externally, and in some environments it is
1134        possible to suppress them. The cheating is now confined to including
1135        certain files from the library's source, which is a bit cleaner.
1136    
1137     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1138        file's purpose clearer.
1139    
1140     5. Reorganized pcre_ucp_findchar().
1141    
1142    
1143    Version 6.3 15-Aug-05
1144    ---------------------
1145    
1146     1. The file libpcre.pc.in did not have general read permission in the tarball.
1147    
1148     2. There were some problems when building without C++ support:
1149    
1150        (a) If C++ support was not built, "make install" and "make test" still
1151            tried to test it.
1152    
1153        (b) There were problems when the value of CXX was explicitly set. Some
1154            changes have been made to try to fix these, and ...
1155    
1156        (c) --disable-cpp can now be used to explicitly disable C++ support.
1157    
1158        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1159            backslash in a target when C++ was disabled. This confuses some
1160            versions of "make", apparently. Using an intermediate variable solves
1161            this. (Same for CPP_LOBJ.)
1162    
1163     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1164        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1165        necessary on certain architectures.
1166    
1167     4. Added a setting of -export-symbols-regex to the link command to remove
1168        those symbols that are exported in the C sense, but actually are local
1169        within the library, and not documented. Their names all begin with
1170        "_pcre_". This is not a perfect job, because (a) we have to except some
1171        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1172        available (and never for static libraries). I have made a note to try to
1173        find a way round (a) in the future.
1174    
1175    
1176    Version 6.2 01-Aug-05
1177    ---------------------
1178    
1179     1. There was no test for integer overflow of quantifier values. A construction
1180        such as {1111111111111111} would give undefined results. What is worse, if
1181        a minimum quantifier for a parenthesized subpattern overflowed and became
1182        negative, the calculation of the memory size went wrong. This could have
1183        led to memory overwriting.
1184    
1185     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1186    
1187     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1188        operating environments where this matters.
1189    
1190     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1191        PCRE options from within the C++ wrapper.
1192    
1193     5. Named capturing subpatterns were not being correctly counted when a pattern
1194        was compiled. This caused two problems: (a) If there were more than 100
1195        such subpatterns, the calculation of the memory needed for the whole
1196        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1197        back references of the form \12, where the number was greater than 9, were
1198        not recognized as back references, even though there were sufficient
1199        previous subpatterns.
1200    
1201     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1202        versions of gcc, e.g. 2.95.4.
1203    
1204    
1205  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1206  ---------------------  ---------------------
1207    

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