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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 259 by ph10, Wed Sep 19 09:52:44 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 when the
36        windows.h file is present (where different names are used). [This was
37        reversed later after testing - see 16 below.]
38    
39    8.  Changed all #include <config.h> to #include "config.h". There were also
40        some further <pcre.h> cases that I changed to "pcre.h".
41    
42    9.  When pcregrep was used with the --colour option, it missed the line ending
43        sequence off the lines that it output.
44    
45    10. It was pointed out to me that arrays of string pointers cause lots of
46        relocations when a shared library is dynamically loaded. A technique of
47        using a single long string with a table of offsets can drastically reduce
48        these. I have refactored PCRE in four places to do this. The result is
49        dramatic:
50    
51          Originally:                          290
52          After changing UCP table:            187
53          After changing error message table:   43
54          After changing table of "verbs"       36
55          After changing table of Posix names   22
56    
57        Thanks to the folks working on Gregex for glib for this insight.
58    
59    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
60        unicode-properties was also set.
61    
62    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
63    
64    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
65        checked only for CRLF.
66    
67    14. Added casts to pcretest.c to avoid compiler warnings.
68    
69    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
70    
71    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
72        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
73        entirely. This removes changes made in 7 above.
74    
75    
76    Version 7.3 28-Aug-07
77    ---------------------
78    
79     1. In the rejigging of the build system that eventually resulted in 7.1, the
80        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
81        brackets there is not right, since it causes compilers to look for an
82        installed pcre.h, not the version that is in the source that is being
83        compiled (which of course may be different). I have changed it back to:
84    
85          #include "pcre.h"
86    
87        I have a vague recollection that the change was concerned with compiling in
88        different directories, but in the new build system, that is taken care of
89        by the VPATH setting the Makefile.
90    
91     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
92        when the subject happened to end in the byte 0x85 (e.g. if the last
93        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
94        characters but of course it shouldn't be taken as a newline when it is part
95        of another character. The bug was that, for an unlimited repeat of . in
96        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
97        characters when looking for a newline.
98    
99     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
100    
101     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
102        in debug output.
103    
104     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
105        long printing in the pcrecpp unittest when running under MinGW.
106    
107     6. ESC_K was left out of the EBCDIC table.
108    
109     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
110        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
111        limit also applies to "virtual nesting" when a pattern is recursive, and in
112        this case 1000 isn't so big. I have been able to remove this limit at the
113        expense of backing off one optimization in certain circumstances. Normally,
114        when pcre_exec() would call its internal match() function recursively and
115        immediately return the result unconditionally, it uses a "tail recursion"
116        feature to save stack. However, when a subpattern that can match an empty
117        string has an unlimited repetition quantifier, it no longer makes this
118        optimization. That gives it a stack frame in which to save the data for
119        checking that an empty string has been matched. Previously this was taken
120        from the 1000-entry workspace that had been reserved. So now there is no
121        explicit limit, but more stack is used.
122    
123     8. Applied Daniel's patches to solve problems with the import/export magic
124        syntax that is required for Windows, and which was going wrong for the
125        pcreposix and pcrecpp parts of the library. These were overlooked when this
126        problem was solved for the main library.
127    
128     9. There were some crude static tests to avoid integer overflow when computing
129        the size of patterns that contain repeated groups with explicit upper
130        limits. As the maximum quantifier is 65535, the maximum group length was
131        set at 30,000 so that the product of these two numbers did not overflow a
132        32-bit integer. However, it turns out that people want to use groups that
133        are longer than 30,000 bytes (though not repeat them that many times).
134        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
135        made it possible to implement the integer overflow checks in a much more
136        dynamic way, which I have now done. The artificial limitation on group
137        length has been removed - we now have only the limit on the total length of
138        the compiled pattern, which depends on the LINK_SIZE setting.
139    
140    10. Fixed a bug in the documentation for get/copy named substring when
141        duplicate names are permitted. If none of the named substrings are set, the
142        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
143        empty string.
144    
145    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
146        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
147        because the ] is interpreted as the first data character and the
148        terminating ] is not found. PCRE has been made compatible with Perl in this
149        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
150        cause memory overwriting.
151    
152    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
153        string has been matched (to stop an infinite loop). It was not recognizing
154        a conditional subpattern that could match an empty string if that
155        subpattern was within another subpattern. For example, it looped when
156        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
157        condition was not nested. This bug has been fixed.
158    
159    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
160        past the start of the subject in the presence of bytes with the top bit
161        set, for example "\x8aBCD".
162    
163    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
164        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
165    
166    14. Optimized (?!) to (*FAIL).
167    
168    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
169        This restricts code points to be within the range 0 to 0x10FFFF, excluding
170        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
171        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
172        does: it's just the validity check that is more restrictive.
173    
174    16. Inserted checks for integer overflows during escape sequence (backslash)
175        processing, and also fixed erroneous offset values for syntax errors during
176        backslash processing.
177    
178    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
179        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
180    
181    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
182        caused an overrun.
183    
184    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
185        something other than just ASCII characters) inside a group that had an
186        unlimited repeat caused a loop at compile time (while checking to see
187        whether the group could match an empty string).
188    
189    20. Debugging a pattern containing \p or \P could cause a crash. For example,
190        [\P{Any}] did so. (Error in the code for printing property names.)
191    
192    21. An orphan \E inside a character class could cause a crash.
193    
194    22. A repeated capturing bracket such as (A)? could cause a wild memory
195        reference during compilation.
196    
197    23. There are several functions in pcre_compile() that scan along a compiled
198        expression for various reasons (e.g. to see if it's fixed length for look
199        behind). There were bugs in these functions when a repeated \p or \P was
200        present in the pattern. These operators have additional parameters compared
201        with \d, etc, and these were not being taken into account when moving along
202        the compiled data. Specifically:
203    
204        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
205            length.
206    
207        (b) An item such as \pL+ within a repeated group could cause crashes or
208            loops.
209    
210        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
211            "reference to non-existent subpattern" error.
212    
213        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
214    
215    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
216        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
217    
218    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
219    
220    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
221        character were causing crashes (broken optimization).
222    
223    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
224        \p or \P) caused a compile-time loop.
225    
226    28. More problems have arisen in unanchored patterns when CRLF is a valid line
227        break. For example, the unstudied pattern [\r\n]A does not match the string
228        "\r\nA" because change 7.0/46 below moves the current point on by two
229        characters after failing to match at the start. However, the pattern \nA
230        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
231        the same is true. There doesn't seem any very clean way out of this, but
232        what I have chosen to do makes the common cases work: PCRE now takes note
233        of whether there can be an explicit match for \r or \n anywhere in the
234        pattern, and if so, 7.0/46 no longer applies. As part of this change,
235        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
236        pattern has explicit CR or LF references.
237    
238    29. Added (*CR) etc for changing newline setting at start of pattern.
239    
240    
241    Version 7.2 19-Jun-07
242    ---------------------
243    
244     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
245        which is apparently normally available under Windows.
246    
247     2. Re-jig the pcregrep tests with different newline settings in an attempt
248        to make them independent of the local environment's newline setting.
249    
250     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
251    
252     4. Some of the "internals" tests were previously cut out when the link size
253        was not 2, because the output contained actual offsets. The recent new
254        "Z" feature of pcretest means that these can be cut out, making the tests
255        usable with all link sizes.
256    
257     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
258        stack recursion. This gives a massive performance boost under BSD, but just
259        a small improvement under Linux. However, it saves one field in the frame
260        in all cases.
261    
262     6. Added more features from the forthcoming Perl 5.10:
263    
264        (a) (?-n) (where n is a string of digits) is a relative subroutine or
265            recursion call. It refers to the nth most recently opened parentheses.
266    
267        (b) (?+n) is also a relative subroutine call; it refers to the nth next
268            to be opened parentheses.
269    
270        (c) Conditions that refer to capturing parentheses can be specified
271            relatively, for example, (?(-2)... or (?(+3)...
272    
273        (d) \K resets the start of the current match so that everything before
274            is not part of it.
275    
276        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
277    
278        (f) \g{name} is another synonym - part of Perl 5.10's unification of
279            reference syntax.
280    
281        (g) (?| introduces a group in which the numbering of parentheses in each
282            alternative starts with the same number.
283    
284        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
285    
286     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
287        PCRE_INFO_JCHANGED.
288    
289     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
290        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
291        for detecting groups that can match an empty string.
292    
293     9. A pattern with a very large number of alternatives (more than several
294        hundred) was running out of internal workspace during the pre-compile
295        phase, where pcre_compile() figures out how much memory will be needed. A
296        bit of new cunning has reduced the workspace needed for groups with
297        alternatives. The 1000-alternative test pattern now uses 12 bytes of
298        workspace instead of running out of the 4096 that are available.
299    
300    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
301    
302    11. Applied patch from Google to remove an optimization that didn't quite work.
303        The report of the bug said:
304    
305          pcrecpp::RE("a*").FullMatch("aaa") matches, while
306          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
307          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
308    
309    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
310        it matched the wrong number of bytes.
311    
312    
313    Version 7.1 24-Apr-07
314    ---------------------
315    
316     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
317        that is more "standard", making use of automake and other Autotools. There
318        is some re-arrangement of the files and adjustment of comments consequent
319        on this.
320    
321     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
322        for recursive directory scanning broke on some systems because the files
323        are not scanned in any specific order and on different systems the order
324        was different. A call to "sort" has been inserted into RunGrepTest for the
325        approprate test as a short-term fix. In the longer term there may be an
326        alternative.
327    
328     3. I had an email from Eric Raymond about problems translating some of PCRE's
329        man pages to HTML (despite the fact that I distribute HTML pages, some
330        people do their own conversions for various reasons). The problems
331        concerned the use of low-level troff macros .br and .in. I have therefore
332        removed all such uses from the man pages (some were redundant, some could
333        be replaced by .nf/.fi pairs). The 132html script that I use to generate
334        HTML has been updated to handle .nf/.fi and to complain if it encounters
335        .br or .in.
336    
337     4. Updated comments in configure.ac that get placed in config.h.in and also
338        arranged for config.h to be included in the distribution, with the name
339        config.h.generic, for the benefit of those who have to compile without
340        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
341    
342     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
343        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
344        makevp.bat for the current PCRE, using the additional files
345        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
346    
347     6. A Windows user reported a minor discrepancy with test 2, which turned out
348        to be caused by a trailing space on an input line that had got lost in his
349        copy. The trailing space was an accident, so I've just removed it.
350    
351     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
352        that is needed.
353    
354     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
355        as "const" (a) because they are and (b) because it helps the PHP
356        maintainers who have recently made a script to detect big data structures
357        in the php code that should be moved to the .rodata section. I remembered
358        to update Builducptable as well, so it won't revert if ucptable.h is ever
359        re-created.
360    
361     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
362        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
363        order to be able to cut out the UTF-8 tables in the latter when UTF-8
364        support is not required. This saves 1.5-2K of code, which is important in
365        some applications.
366    
367        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
368        so as not to refer to the tables, even though these functions will never be
369        called when UTF-8 support is disabled. Otherwise there are problems with a
370        shared library.
371    
372    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
373    
374        (a) It was defining its arguments as char * instead of void *.
375    
376        (b) It was assuming that all moves were upwards in memory; this was true
377            a long time ago when I wrote it, but is no longer the case.
378    
379        The emulated memove() is provided for those environments that have neither
380        memmove() nor bcopy(). I didn't think anyone used it these days, but that
381        is clearly not the case, as these two bugs were recently reported.
382    
383    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
384        and Detrail to create the HTML documentation, the .txt form of the man
385        pages, and it removes trailing spaces from listed files. It also creates
386        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
387        case, it wraps all the #defines with #ifndefs. This script should be run
388        before "make dist".
389    
390    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
391        with Unicode property support.
392    
393        (a) For a maximizing quantifier, if the two different cases of the
394            character were of different lengths in their UTF-8 codings (there are
395            some cases like this - I found 11), and the matching function had to
396            back up over a mixture of the two cases, it incorrectly assumed they
397            were both the same length.
398    
399        (b) When PCRE was configured to use the heap rather than the stack for
400            recursion during matching, it was not correctly preserving the data for
401            the other case of a UTF-8 character when checking ahead for a match
402            while processing a minimizing repeat. If the check also involved
403            matching a wide character, but failed, corruption could cause an
404            erroneous result when trying to check for a repeat of the original
405            character.
406    
407    13. Some tidying changes to the testing mechanism:
408    
409        (a) The RunTest script now detects the internal link size and whether there
410            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
411            values substituted by "configure". (The RunGrepTest script already did
412            this for UTF-8.) The configure.ac script no longer substitutes the
413            relevant variables.
414    
415        (b) The debugging options /B and /D in pcretest show the compiled bytecode
416            with length and offset values. This means that the output is different
417            for different internal link sizes. Test 2 is skipped for link sizes
418            other than 2 because of this, bypassing the problem. Unfortunately,
419            there was also a test in test 3 (the locale tests) that used /B and
420            failed for link sizes other than 2. Rather than cut the whole test out,
421            I have added a new /Z option to pcretest that replaces the length and
422            offset values with spaces. This is now used to make test 3 independent
423            of link size. (Test 2 will be tidied up later.)
424    
425    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
426        segmentation fault instead of returning the appropriate error message.
427    
428    15. In multiline mode when the newline sequence was set to "any", the pattern
429        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
430        This doesn't seem right; it now treats the CRLF combination as the line
431        ending, and so does not match in that case. It's only a pattern such as ^$
432        that would hit this one: something like ^ABC$ would have failed after \r
433        and then tried again after \r\n.
434    
435    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
436        in an attempt to make files that differ only in their line terminators
437        compare equal. This works on Linux.
438    
439    17. Under certain error circumstances pcregrep might try to free random memory
440        as it exited. This is now fixed, thanks to valgrind.
441    
442    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
443        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
444        was because its rules for how to advance for /g after matching an empty
445        string at the end of a line did not allow for this case. They now check for
446        it specially.
447    
448    20. pcretest is supposed to handle patterns and data of any length, by
449        extending its buffers when necessary. It was getting this wrong when the
450        buffer for a data line had to be extended.
451    
452    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
453        CRLF as a newline sequence.
454    
455    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
456        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
457        I have nevertheless tidied it up.
458    
459    23. Added some casts to kill warnings from HP-UX ia64 compiler.
460    
461    24. Added a man page for pcre-config.
462    
463    
464    Version 7.0 19-Dec-06
465    ---------------------
466    
467     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
468        moving to gcc 4.1.1.
469    
470     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
471        sys/time.h, which is documented as needed for this function. It doesn't
472        seem to matter on Linux, but it showed up on some releases of OS X.
473    
474     3. It seems that there are systems where bytes whose values are greater than
475        127 match isprint() in the "C" locale. The "C" locale should be the
476        default when a C program starts up. In most systems, only ASCII printing
477        characters match isprint(). This difference caused the output from pcretest
478        to vary, making some of the tests fail. I have changed pcretest so that:
479    
480        (a) When it is outputting text in the compiled version of a pattern, bytes
481            other than 32-126 are always shown as hex escapes.
482    
483        (b) When it is outputting text that is a matched part of a subject string,
484            it does the same, unless a different locale has been set for the match
485            (using the /L modifier). In this case, it uses isprint() to decide.
486    
487     4. Fixed a major bug that caused incorrect computation of the amount of memory
488        required for a compiled pattern when options that changed within the
489        pattern affected the logic of the preliminary scan that determines the
490        length. The relevant options are -x, and -i in UTF-8 mode. The result was
491        that the computed length was too small. The symptoms of this bug were
492        either the PCRE error "internal error: code overflow" from pcre_compile(),
493        or a glibc crash with a message such as "pcretest: free(): invalid next
494        size (fast)". Examples of patterns that provoked this bug (shown in
495        pcretest format) are:
496    
497          /(?-x: )/x
498          /(?x)(?-x: \s*#\s*)/
499          /((?i)[\x{c0}])/8
500          /(?i:[\x{c0}])/8
501    
502        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
503        is now done differently.
504    
505     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
506        wrapper classes; (b) implement a new function in the C++ scanner that is
507        more efficient than the old way of doing things because it avoids levels of
508        recursion in the regex matching; (c) add a paragraph to the documentation
509        for the FullMatch() function.
510    
511     6. The escape sequence \n was being treated as whatever was defined as
512        "newline". Not only was this contrary to the documentation, which states
513        that \n is character 10 (hex 0A), but it also went horribly wrong when
514        "newline" was defined as CRLF. This has been fixed.
515    
516     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
517        was being set to -1 for the "end of line" case (supposedly a value that no
518        character can have). Though this value is never used (the check for end of
519        line is "zero bytes in current character"), it caused compiler complaints.
520        I've changed it to 0xffffffff.
521    
522     8. In pcre_version.c, the version string was being built by a sequence of
523        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
524        string (as it is for production releases) called a macro with an empty
525        argument. The C standard says the result of this is undefined. The gcc
526        compiler treats it as an empty string (which was what was wanted) but it is
527        reported that Visual C gives an error. The source has been hacked around to
528        avoid this problem.
529    
530     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
531        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
532        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
533        of them did).
534    
535    10. Originally, pcretest opened its input and output without "b"; then I was
536        told that "b" was needed in some environments, so it was added for release
537        5.0 to both the input and output. (It makes no difference on Unix-like
538        systems.) Later I was told that it is wrong for the input on Windows. I've
539        now abstracted the modes into two macros, to make it easier to fiddle with
540        them, and removed "b" from the input mode under Windows.
541    
542    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
543    
544    12. Added -help and --help to pcretest as an official way of being reminded
545        of the options.
546    
547    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
548        and pcrecpp.cc because they annoy compilers at high warning levels.
549    
550    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
551    
552    15. Fixed an occurrence of == in configure.ac that should have been = (shell
553        scripts are not C programs :-) and which was not noticed because it works
554        on Linux.
555    
556    16. pcretest is supposed to handle any length of pattern and data line (as one
557        line or as a continued sequence of lines) by extending its input buffer if
558        necessary. This feature was broken for very long pattern lines, leading to
559        a string of junk being passed to pcre_compile() if the pattern was longer
560        than about 50K.
561    
562    17. I have done a major re-factoring of the way pcre_compile() computes the
563        amount of memory needed for a compiled pattern. Previously, there was code
564        that made a preliminary scan of the pattern in order to do this. That was
565        OK when PCRE was new, but as the facilities have expanded, it has become
566        harder and harder to keep it in step with the real compile phase, and there
567        have been a number of bugs (see for example, 4 above). I have now found a
568        cunning way of running the real compile function in a "fake" mode that
569        enables it to compute how much memory it would need, while actually only
570        ever using a few hundred bytes of working memory and without too many
571        tests of the mode. This should make future maintenance and development
572        easier. A side effect of this work is that the limit of 200 on the nesting
573        depth of parentheses has been removed (though this was never a serious
574        limitation, I suspect). However, there is a downside: pcre_compile() now
575        runs more slowly than before (30% or more, depending on the pattern). I
576        hope this isn't a big issue. There is no effect on runtime performance.
577    
578    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
579        newline (only possible for the last line of a file) and it was a
580        pattern that set a locale (followed by /Lsomething), pcretest crashed.
581    
582    19. Added additional timing features to pcretest. (1) The -tm option now times
583        matching only, not compiling. (2) Both -t and -tm can be followed, as a
584        separate command line item, by a number that specifies the number of
585        repeats to use when timing. The default is 50000; this gives better
586        precision, but takes uncomfortably long for very large patterns.
587    
588    20. Extended pcre_study() to be more clever in cases where a branch of a
589        subpattern has no definite first character. For example, (a*|b*)[cd] would
590        previously give no result from pcre_study(). Now it recognizes that the
591        first character must be a, b, c, or d.
592    
593    21. There was an incorrect error "recursive call could loop indefinitely" if
594        a subpattern (or the entire pattern) that was being tested for matching an
595        empty string contained only one non-empty item after a nested subpattern.
596        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
597        incorrectly, because the \d was being skipped in the check.
598    
599    22. The pcretest program now has a new pattern option /B and a command line
600        option -b, which is equivalent to adding /B to every pattern. This causes
601        it to show the compiled bytecode, without the additional information that
602        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
603        is the same as /B/I).
604    
605    23. A new optimization is now able automatically to treat some sequences such
606        as a*b as a*+b. More specifically, if something simple (such as a character
607        or a simple class like \d) has an unlimited quantifier, and is followed by
608        something that cannot possibly match the quantified thing, the quantifier
609        is automatically "possessified".
610    
611    24. A recursive reference to a subpattern whose number was greater than 39
612        went wrong under certain circumstances in UTF-8 mode. This bug could also
613        have affected the operation of pcre_study().
614    
615    25. Realized that a little bit of performance could be had by replacing
616        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
617    
618    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
619    
620    27. Possessive quantifiers such as a++ were previously implemented by turning
621        them into atomic groups such as ($>a+). Now they have their own opcodes,
622        which improves performance. This includes the automatically created ones
623        from 23 above.
624    
625    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
626        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
627        the first matched character to be a colon. This applied both to named and
628        numbered groups.
629    
630    29. The ucpinternal.h header file was missing its idempotency #ifdef.
631    
632    30. I was sent a "project" file called libpcre.a.dev which I understand makes
633        building PCRE on Windows easier, so I have included it in the distribution.
634    
635    31. There is now a check in pcretest against a ridiculously large number being
636        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
637        loop, the loop is abandoned.
638    
639    32. Forward references to subpatterns in conditions such as (?(2)...) where
640        subpattern 2 is defined later cause pcre_compile() to search forwards in
641        the pattern for the relevant set of parentheses. This search went wrong
642        when there were unescaped parentheses in a character class, parentheses
643        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
644    
645    33. "Subroutine" calls and backreferences were previously restricted to
646        referencing subpatterns earlier in the regex. This restriction has now
647        been removed.
648    
649    34. Added a number of extra features that are going to be in Perl 5.10. On the
650        whole, these are just syntactic alternatives for features that PCRE had
651        previously implemented using the Python syntax or my own invention. The
652        other formats are all retained for compatibility.
653    
654        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
655            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
656            also .NET compatible.
657    
658        (b) A recursion or subroutine call to a named group can now be defined as
659            (?&name) as well as (?P>name).
660    
661        (c) A backreference to a named group can now be defined as \k<name> or
662            \k'name' as well as (?P=name). The new forms, as well as being in Perl
663            5.10, are also .NET compatible.
664    
665        (d) A conditional reference to a named group can now use the syntax
666            (?(<name>) or (?('name') as well as (?(name).
667    
668        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
669            groups (named and numbered) that are never evaluated inline, but can be
670            called as "subroutines" from elsewhere. In effect, the DEFINE condition
671            is always false. There may be only one alternative in such a group.
672    
673        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
674            as the simple (?(R). The condition is true only if the most recent
675            recursion is that of the given number or name. It does not search out
676            through the entire recursion stack.
677    
678        (g) The escape \gN or \g{N} has been added, where N is a positive or
679            negative number, specifying an absolute or relative reference.
680    
681    35. Tidied to get rid of some further signed/unsigned compiler warnings and
682        some "unreachable code" warnings.
683    
684    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
685        things, this adds five new scripts.
686    
687    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
688        There were also incompatibilities regarding the handling of \Q..\E inside
689        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
690        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
691    
692    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
693        matches an empty string, and forcibly breaks the loop. There were bugs in
694        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
695        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
696        separate and independent bugs (that affected different cases) have been
697        fixed.
698    
699    39. Refactored the code to abolish the use of different opcodes for small
700        capturing bracket numbers. This is a tidy that I avoided doing when I
701        removed the limit on the number of capturing brackets for 3.5 back in 2001.
702        The new approach is not only tidier, it makes it possible to reduce the
703        memory needed to fix the previous bug (38).
704    
705    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
706        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
707        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
708        mode.
709    
710    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
711        report.
712    
713    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
714        copy construction and assignment in the C++ wrapper.
715    
716    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
717        couple of bugs that could have given wrong results in the "--newline=crlf"
718        case.
719    
720    44. Added a number of casts and did some reorganization of signed/unsigned int
721        variables following suggestions from Dair Grant. Also renamed the variable
722        "this" as "item" because it is a C++ keyword.
723    
724    45. Arranged for dftables to add
725    
726          #include "pcre_internal.h"
727    
728        to pcre_chartables.c because without it, gcc 4.x may remove the array
729        definition from the final binary if PCRE is built into a static library and
730        dead code stripping is activated.
731    
732    46. For an unanchored pattern, if a match attempt fails at the start of a
733        newline sequence, and the newline setting is CRLF or ANY, and the next two
734        characters are CRLF, advance by two characters instead of one.
735    
736    
737    Version 6.7 04-Jul-06
738    ---------------------
739    
740     1. In order to handle tests when input lines are enormously long, pcretest has
741        been re-factored so that it automatically extends its buffers when
742        necessary. The code is crude, but this _is_ just a test program. The
743        default size has been increased from 32K to 50K.
744    
745     2. The code in pcre_study() was using the value of the re argument before
746        testing it for NULL. (Of course, in any sensible call of the function, it
747        won't be NULL.)
748    
749     3. The memmove() emulation function in pcre_internal.h, which is used on
750        systems that lack both memmove() and bcopy() - that is, hardly ever -
751        was missing a "static" storage class specifier.
752    
753     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
754        containing an extended class (one that cannot be represented by a bitmap
755        because it contains high-valued characters or Unicode property items, e.g.
756        [\pZ]). Almost always one would set UTF-8 mode when processing such a
757        pattern, but PCRE should not loop if you do not (it no longer does).
758        [Detail: two cases were found: (a) a repeated subpattern containing an
759        extended class; (b) a recursive reference to a subpattern that followed a
760        previous extended class. It wasn't skipping over the extended class
761        correctly when UTF-8 mode was not set.]
762    
763     5. A negated single-character class was not being recognized as fixed-length
764        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
765        compile error "lookbehind assertion is not fixed length".
766    
767     6. The RunPerlTest auxiliary script was showing an unexpected difference
768        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
769        write a Perl script that can interpret lines of an input file either as
770        byte characters or as UTF-8, which is what "perltest" was being required to
771        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
772        can't do is switch easily at run time between having the "use utf8;" pragma
773        or not. In the end, I fudged it by using the RunPerlTest script to insert
774        "use utf8;" explicitly for the UTF-8 tests.
775    
776     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
777        the end of the subject string, contrary to the documentation and to what
778        Perl does. This was true of both matching functions. Now it matches only at
779        the start of the subject and immediately after *internal* newlines.
780    
781     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
782        a pointer to an int instead of a pointer to an unsigned long int. This
783        caused problems on 64-bit systems.
784    
785     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
786        instance of the 'standard' template library not being so standard".
787    
788    10. There was no check on the number of named subpatterns nor the maximum
789        length of a subpattern name. The product of these values is used to compute
790        the size of the memory block for a compiled pattern. By supplying a very
791        long subpattern name and a large number of named subpatterns, the size
792        computation could be caused to overflow. This is now prevented by limiting
793        the length of names to 32 characters, and the number of named subpatterns
794        to 10,000.
795    
796    11. Subpatterns that are repeated with specific counts have to be replicated in
797        the compiled pattern. The size of memory for this was computed from the
798        length of the subpattern and the repeat count. The latter is limited to
799        65535, but there was no limit on the former, meaning that integer overflow
800        could in principle occur. The compiled length of a repeated subpattern is
801        now limited to 30,000 bytes in order to prevent this.
802    
803    12. Added the optional facility to have named substrings with the same name.
804    
805    13. Added the ability to use a named substring as a condition, using the
806        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
807        are numbers (not recommended). Forward references are permitted.
808    
809    14. Added forward references in named backreferences (if you see what I mean).
810    
811    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
812        pattern could run off the end of the subject. For example, the pattern
813        "(?s)(.{1,5})"8 did this with the subject "ab".
814    
815    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
816        PCRE_CASELESS was set when matching characters that were quantified with ?
817        or *.
818    
819    17. A character class other than a single negated character that had a minimum
820        but no maximum quantifier - for example [ab]{6,} - was not handled
821        correctly by pce_dfa_exec(). It would match only one character.
822    
823    18. A valid (though odd) pattern that looked like a POSIX character
824        class but used an invalid character after [ (for example [[,abc,]]) caused
825        pcre_compile() to give the error "Failed: internal error: code overflow" or
826        in some cases to crash with a glibc free() error. This could even happen if
827        the pattern terminated after [[ but there just happened to be a sequence of
828        letters, a binary zero, and a closing ] in the memory that followed.
829    
830    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
831        over the years. Originally (before any Unicode support), just the bottom 8
832        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
833        output from "man perlunicode" includes this:
834    
835          The regular expression compiler produces polymorphic opcodes.  That
836          is, the pattern adapts to the data and automatically switches to
837          the Unicode character scheme when presented with Unicode data--or
838          instead uses a traditional byte scheme when presented with byte
839          data.
840    
841        Sadly, a wide octal escape does not cause a switch, and in a string with
842        no other multibyte characters, these octal escapes are treated as before.
843        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
844        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
845        Unicode string.
846    
847        I have not perpetrated such confusion in PCRE. Up till now, it took just
848        the bottom 8 bits, as in old Perl. I have now made octal escapes with
849        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
850        translate to the appropriate multibyte character.
851    
852    29. Applied some refactoring to reduce the number of warnings from Microsoft
853        and Borland compilers. This has included removing the fudge introduced
854        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
855        a warning about an unused variable.
856    
857    21. PCRE has not included VT (character 0x0b) in the set of whitespace
858        characters since release 4.0, because Perl (from release 5.004) does not.
859        [Or at least, is documented not to: some releases seem to be in conflict
860        with the documentation.] However, when a pattern was studied with
861        pcre_study() and all its branches started with \s, PCRE still included VT
862        as a possible starting character. Of course, this did no harm; it just
863        caused an unnecessary match attempt.
864    
865    22. Removed a now-redundant internal flag bit that recorded the fact that case
866        dependency changed within the pattern. This was once needed for "required
867        byte" processing, but is no longer used. This recovers a now-scarce options
868        bit. Also moved the least significant internal flag bit to the most-
869        significant bit of the word, which was not previously used (hangover from
870        the days when it was an int rather than a uint) to free up another bit for
871        the future.
872    
873    23. Added support for CRLF line endings as well as CR and LF. As well as the
874        default being selectable at build time, it can now be changed at runtime
875        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
876        specify that it is scanning data with non-default line endings.
877    
878    24. Changed the definition of CXXLINK to make it agree with the definition of
879        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
880    
881    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
882        recursions. This makes a big different to stack usage for some patterns.
883    
884    26. If a subpattern containing a named recursion or subroutine reference such
885        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
886        the space required for the compiled pattern went wrong and gave too small a
887        value. Depending on the environment, this could lead to "Failed: internal
888        error: code overflow at offset 49" or "glibc detected double free or
889        corruption" errors.
890    
891    27. Applied patches from Google (a) to support the new newline modes and (b) to
892        advance over multibyte UTF-8 characters in GlobalReplace.
893    
894    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
895        difference for some implementation of PCRE in some Windows version.
896    
897    29. Added some extra testing facilities to pcretest:
898    
899        \q<number>   in a data line sets the "match limit" value
900        \Q<number>   in a data line sets the "match recursion limt" value
901        -S <number>  sets the stack size, where <number> is in megabytes
902    
903        The -S option isn't available for Windows.
904    
905    
906    Version 6.6 06-Feb-06
907    ---------------------
908    
909     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
910        in pcreposix.h. I have copied the definition from pcre.h.
911    
912     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
913        because pcre.h is no longer a built file.
914    
915     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
916        not normally included in the compiled code.
917    
918    
919    Version 6.5 01-Feb-06
920    ---------------------
921    
922     1. When using the partial match feature with pcre_dfa_exec(), it was not
923        anchoring the second and subsequent partial matches at the new starting
924        point. This could lead to incorrect results. For example, with the pattern
925        /1234/, partially matching against "123" and then "a4" gave a match.
926    
927     2. Changes to pcregrep:
928    
929        (a) All non-match returns from pcre_exec() were being treated as failures
930            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
931            error message is output. Some extra information is given for the
932            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
933            probably the only errors that are likely to be caused by users (by
934            specifying a regex that has nested indefinite repeats, for instance).
935            If there are more than 20 of these errors, pcregrep is abandoned.
936    
937        (b) A binary zero was treated as data while matching, but terminated the
938            output line if it was written out. This has been fixed: binary zeroes
939            are now no different to any other data bytes.
940    
941        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
942            used to set a locale for matching. The --locale=xxxx long option has
943            been added (no short equivalent) to specify a locale explicitly on the
944            pcregrep command, overriding the environment variables.
945    
946        (d) When -B was used with -n, some line numbers in the output were one less
947            than they should have been.
948    
949        (e) Added the -o (--only-matching) option.
950    
951        (f) If -A or -C was used with -c (count only), some lines of context were
952            accidentally printed for the final match.
953    
954        (g) Added the -H (--with-filename) option.
955    
956        (h) The combination of options -rh failed to suppress file names for files
957            that were found from directory arguments.
958    
959        (i) Added the -D (--devices) and -d (--directories) options.
960    
961        (j) Added the -F (--fixed-strings) option.
962    
963        (k) Allow "-" to be used as a file name for -f as well as for a data file.
964    
965        (l) Added the --colo(u)r option.
966    
967        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
968            is not present by default.
969    
970     3. A nasty bug was discovered in the handling of recursive patterns, that is,
971        items such as (?R) or (?1), when the recursion could match a number of
972        alternatives. If it matched one of the alternatives, but subsequently,
973        outside the recursion, there was a failure, the code tried to back up into
974        the recursion. However, because of the way PCRE is implemented, this is not
975        possible, and the result was an incorrect result from the match.
976    
977        In order to prevent this happening, the specification of recursion has
978        been changed so that all such subpatterns are automatically treated as
979        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
980    
981     4. I had overlooked the fact that, in some locales, there are characters for
982        which isalpha() is true but neither isupper() nor islower() are true. In
983        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
984        and ordfeminine) are like this. This affected the treatment of \w and \W
985        when they appeared in character classes, but not when they appeared outside
986        a character class. The bit map for "word" characters is now created
987        separately from the results of isalnum() instead of just taking it from the
988        upper, lower, and digit maps. (Plus the underscore character, of course.)
989    
990     5. The above bug also affected the handling of POSIX character classes such as
991        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
992        permanent tables. Instead, the bit maps for such a class were previously
993        created as the appropriate unions of the upper, lower, and digit bitmaps.
994        Now they are created by subtraction from the [[:word:]] class, which has
995        its own bitmap.
996    
997     6. The [[:blank:]] character class matches horizontal, but not vertical space.
998        It is created by subtracting the vertical space characters (\x09, \x0a,
999        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1000        subtraction was done in the overall bitmap for a character class, meaning
1001        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1002        be recognized. This bug has been fixed.
1003    
1004     7. Patches from the folks at Google:
1005    
1006          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1007          real life, but is still worth protecting against".
1008    
1009          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1010          regular expressions".
1011    
1012          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1013          have it.
1014    
1015          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1016          "configure" and the latter not, in order to fix a problem somebody had
1017          with compiling the Arg class on HP-UX.
1018    
1019          (e) Improve the error-handling of the C++ wrapper a little bit.
1020    
1021          (f) New tests for checking recursion limiting.
1022    
1023     8. The pcre_memmove() function, which is used only if the environment does not
1024        have a standard memmove() function (and is therefore rarely compiled),
1025        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1026        returning a result (though PCRE never actually uses the result).
1027    
1028     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1029        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1030        returned instead of calling malloc() with an overflowing number that would
1031        most likely cause subsequent chaos.
1032    
1033    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1034    
1035    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1036        with this option is matched, the nmatch and pmatch options of regexec() are
1037        ignored.
1038    
1039    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1040        provided in case anyone wants to the the POSIX interface with UTF-8
1041        strings.
1042    
1043    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1044        C++ linking (needed for some HP-UX environments).
1045    
1046    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1047        (unused parameter) and in the pcre_printint() function (omitted "default"
1048        switch label when the default is to do nothing).
1049    
1050    15. Added some code to make it possible, when PCRE is compiled as a C++
1051        library, to replace subject pointers for pcre_exec() with a smart pointer
1052        class, thus making it possible to process discontinuous strings.
1053    
1054    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1055        much the same function. They were added by different people who were trying
1056        to make PCRE easy to compile on non-Unix systems. It has been suggested
1057        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1058        for compiling on Windows systems. I have therefore replaced it with
1059        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1060        defaults to "extern" for C or "extern C" for C++, which works fine on
1061        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1062        SCOPE with something explicit in config.h. In addition:
1063    
1064        (a) pcreposix.h still had just "extern" instead of either of these macros;
1065            I have replaced it with PCRE_DATA_SCOPE.
1066    
1067        (b) Functions such as _pcre_xclass(), which are internal to the library,
1068            but external in the C sense, all had PCRE_EXPORT in their definitions.
1069            This is apparently wrong for the Windows case, so I have removed it.
1070            (It makes no difference on Unix-like systems.)
1071    
1072    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1073        of recursive calls to match(). This is different to MATCH_LIMIT because
1074        that limits the total number of calls to match(), not all of which increase
1075        the depth of recursion. Limiting the recursion depth limits the amount of
1076        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1077        when PCRE is compiled, and changed at run time. A patch from Google adds
1078        this functionality to the C++ interface.
1079    
1080    18. Changes to the handling of Unicode character properties:
1081    
1082        (a) Updated the table to Unicode 4.1.0.
1083    
1084        (b) Recognize characters that are not in the table as "Cn" (undefined).
1085    
1086        (c) I revised the way the table is implemented to a much improved format
1087            which includes recognition of ranges. It now supports the ranges that
1088            are defined in UnicodeData.txt, and it also amalgamates other
1089            characters into ranges. This has reduced the number of entries in the
1090            table from around 16,000 to around 3,000, thus reducing its size
1091            considerably. I realized I did not need to use a tree structure after
1092            all - a binary chop search is just as efficient. Having reduced the
1093            number of entries, I extended their size from 6 bytes to 8 bytes to
1094            allow for more data.
1095    
1096        (d) Added support for Unicode script names via properties such as \p{Han}.
1097    
1098    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1099        matching that character.
1100    
1101    20. When matching a repeated Unicode property with a minimum greater than zero,
1102        (for example \pL{2,}), PCRE could look past the end of the subject if it
1103        reached it while seeking the minimum number of characters. This could
1104        happen only if some of the characters were more than one byte long, because
1105        there is a check for at least the minimum number of bytes.
1106    
1107    21. Refactored the implementation of \p and \P so as to be more general, to
1108        allow for more different types of property in future. This has changed the
1109        compiled form incompatibly. Anybody with saved compiled patterns that use
1110        \p or \P will have to recompile them.
1111    
1112    22. Added "Any" and "L&" to the supported property types.
1113    
1114    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1115        but give a compile time error if the value is greater than 0xff.
1116    
1117    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1118        accidentally not being installed or uninstalled.
1119    
1120    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1121        made were to insert the current release number. This seemed silly, because
1122        it made things harder for people building PCRE on systems that don't run
1123        "configure". I have turned pcre.h into a distributed file, no longer built
1124        by "configure", with the version identification directly included. There is
1125        no longer a pcre.h.in file.
1126    
1127        However, this change necessitated a change to the pcre-config script as
1128        well. It is built from pcre-config.in, and one of the substitutions was the
1129        release number. I have updated configure.ac so that ./configure now finds
1130        the release number by grepping pcre.h.
1131    
1132    26. Added the ability to run the tests under valgrind.
1133    
1134    
1135    Version 6.4 05-Sep-05
1136    ---------------------
1137    
1138     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1139        "--" to be printed when multiple files were scanned, even when none of the
1140        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1141        consider it to be a bug, and have restored the previous behaviour.
1142    
1143     2. A couple of code tidies to get rid of compiler warnings.
1144    
1145     3. The pcretest program used to cheat by referring to symbols in the library
1146        whose names begin with _pcre_. These are internal symbols that are not
1147        really supposed to be visible externally, and in some environments it is
1148        possible to suppress them. The cheating is now confined to including
1149        certain files from the library's source, which is a bit cleaner.
1150    
1151     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1152        file's purpose clearer.
1153    
1154     5. Reorganized pcre_ucp_findchar().
1155    
1156    
1157    Version 6.3 15-Aug-05
1158    ---------------------
1159    
1160     1. The file libpcre.pc.in did not have general read permission in the tarball.
1161    
1162     2. There were some problems when building without C++ support:
1163    
1164        (a) If C++ support was not built, "make install" and "make test" still
1165            tried to test it.
1166    
1167        (b) There were problems when the value of CXX was explicitly set. Some
1168            changes have been made to try to fix these, and ...
1169    
1170        (c) --disable-cpp can now be used to explicitly disable C++ support.
1171    
1172        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1173            backslash in a target when C++ was disabled. This confuses some
1174            versions of "make", apparently. Using an intermediate variable solves
1175            this. (Same for CPP_LOBJ.)
1176    
1177     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1178        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1179        necessary on certain architectures.
1180    
1181     4. Added a setting of -export-symbols-regex to the link command to remove
1182        those symbols that are exported in the C sense, but actually are local
1183        within the library, and not documented. Their names all begin with
1184        "_pcre_". This is not a perfect job, because (a) we have to except some
1185        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1186        available (and never for static libraries). I have made a note to try to
1187        find a way round (a) in the future.
1188    
1189    
1190    Version 6.2 01-Aug-05
1191    ---------------------
1192    
1193     1. There was no test for integer overflow of quantifier values. A construction
1194        such as {1111111111111111} would give undefined results. What is worse, if
1195        a minimum quantifier for a parenthesized subpattern overflowed and became
1196        negative, the calculation of the memory size went wrong. This could have
1197        led to memory overwriting.
1198    
1199     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1200    
1201     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1202        operating environments where this matters.
1203    
1204     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1205        PCRE options from within the C++ wrapper.
1206    
1207     5. Named capturing subpatterns were not being correctly counted when a pattern
1208        was compiled. This caused two problems: (a) If there were more than 100
1209        such subpatterns, the calculation of the memory needed for the whole
1210        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1211        back references of the form \12, where the number was greater than 9, were
1212        not recognized as back references, even though there were sufficient
1213        previous subpatterns.
1214    
1215     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1216        versions of gcc, e.g. 2.95.4.
1217    
1218    
1219  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1220  ---------------------  ---------------------
1221    

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