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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 295 by ph10, Mon Dec 31 17:00:24 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.5 31-Dec-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. Added --file-offsets and --line-offsets to pcregrep.
80    
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
85    
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
89    
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
95    
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97    
98    19. Added --enable-pcretest-libreadline.
99    
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I have removed one of the increments.
103    
104    21. Several CMake things:
105    
106        (1) Arranged that, when cmake is used on Unix, the libraries end up with
107            the names libpcre and libpcreposix, not just pcre and pcreposix.
108    
109        (2) The above change means that pcretest and pcregrep are now correctly
110            linked with the newly-built libraries, not previously installed ones.
111    
112        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
113    
114    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
115        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
116        UTF-8 newline character). The key issue is that the pattern starts .*;
117        this means that the match must be either at the beginning, or after a
118        newline. The bug was in the code for advancing after a failed match and
119        checking that the new position followed a newline. It was not taking
120        account of UTF-8 characters correctly.
121    
122    23. PCRE was behaving differently from Perl in the way it recognized POSIX
123        character classes. PCRE was not treating the sequence [:...:] as a
124        character class unless the ... were all letters. Perl, however, seems to
125        allow any characters between [: and :], though of course it rejects as
126        unknown any "names" that contain non-letters, because all the known class
127        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
128        for example, whereas PCRE did not - it did not recognize a POSIX character
129        class. This seemed a bit dangerous, so the code has been changed to be
130        closer to Perl. The behaviour is not identical to Perl, because PCRE will
131        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
132        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
133        Perl does, and where it didn't before.
134    
135    
136    Version 7.4 21-Sep-07
137    ---------------------
138    
139    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
140        means that a class such as [\s] counted as "explicit reference to CR or
141        LF". That isn't really right - the whole point of the change was to try to
142        help when there was an actual mention of one of the two characters. So now
143        the change happens only if \r or \n (or a literal CR or LF) character is
144        encountered.
145    
146    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
147        of both had grown to the point where there were only 3 bits left.
148        Fortunately, there was spare space in the data structure, and so I have
149        moved the internal flags into a new 16-bit field to free up more option
150        bits.
151    
152    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
153        but did not set the internal JCHANGED flag - either of these is enough to
154        control the way the "get" function works - but the PCRE_INFO_JCHANGED
155        facility is supposed to tell if (?J) was ever used, so now (?J) at the
156        start sets both bits.
157    
158    4.  Added options (at build time, compile time, exec time) to change \R from
159        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
160    
161    5.  doc/pcresyntax.html was missing from the distribution.
162    
163    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
164        compatibility, even though it is no longer used.
165    
166    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
167        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
168        windows.h file is present (where different names are used). [This was
169        reversed later after testing - see 16 below.]
170    
171    8.  Changed all #include <config.h> to #include "config.h". There were also
172        some further <pcre.h> cases that I changed to "pcre.h".
173    
174    9.  When pcregrep was used with the --colour option, it missed the line ending
175        sequence off the lines that it output.
176    
177    10. It was pointed out to me that arrays of string pointers cause lots of
178        relocations when a shared library is dynamically loaded. A technique of
179        using a single long string with a table of offsets can drastically reduce
180        these. I have refactored PCRE in four places to do this. The result is
181        dramatic:
182    
183          Originally:                          290
184          After changing UCP table:            187
185          After changing error message table:   43
186          After changing table of "verbs"       36
187          After changing table of Posix names   22
188    
189        Thanks to the folks working on Gregex for glib for this insight.
190    
191    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
192        unicode-properties was also set.
193    
194    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
195    
196    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
197        checked only for CRLF.
198    
199    14. Added casts to pcretest.c to avoid compiler warnings.
200    
201    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
202    
203    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
204        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
205        entirely. This removes changes made in 7 above.
206    
207    17. The CMake files have been updated, and there is now more information about
208        building with CMake in the NON-UNIX-USE document.
209    
210    
211    Version 7.3 28-Aug-07
212    ---------------------
213    
214     1. In the rejigging of the build system that eventually resulted in 7.1, the
215        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
216        brackets there is not right, since it causes compilers to look for an
217        installed pcre.h, not the version that is in the source that is being
218        compiled (which of course may be different). I have changed it back to:
219    
220          #include "pcre.h"
221    
222        I have a vague recollection that the change was concerned with compiling in
223        different directories, but in the new build system, that is taken care of
224        by the VPATH setting the Makefile.
225    
226     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
227        when the subject happened to end in the byte 0x85 (e.g. if the last
228        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
229        characters but of course it shouldn't be taken as a newline when it is part
230        of another character. The bug was that, for an unlimited repeat of . in
231        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
232        characters when looking for a newline.
233    
234     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
235    
236     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
237        in debug output.
238    
239     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
240        long printing in the pcrecpp unittest when running under MinGW.
241    
242     6. ESC_K was left out of the EBCDIC table.
243    
244     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
245        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
246        limit also applies to "virtual nesting" when a pattern is recursive, and in
247        this case 1000 isn't so big. I have been able to remove this limit at the
248        expense of backing off one optimization in certain circumstances. Normally,
249        when pcre_exec() would call its internal match() function recursively and
250        immediately return the result unconditionally, it uses a "tail recursion"
251        feature to save stack. However, when a subpattern that can match an empty
252        string has an unlimited repetition quantifier, it no longer makes this
253        optimization. That gives it a stack frame in which to save the data for
254        checking that an empty string has been matched. Previously this was taken
255        from the 1000-entry workspace that had been reserved. So now there is no
256        explicit limit, but more stack is used.
257    
258     8. Applied Daniel's patches to solve problems with the import/export magic
259        syntax that is required for Windows, and which was going wrong for the
260        pcreposix and pcrecpp parts of the library. These were overlooked when this
261        problem was solved for the main library.
262    
263     9. There were some crude static tests to avoid integer overflow when computing
264        the size of patterns that contain repeated groups with explicit upper
265        limits. As the maximum quantifier is 65535, the maximum group length was
266        set at 30,000 so that the product of these two numbers did not overflow a
267        32-bit integer. However, it turns out that people want to use groups that
268        are longer than 30,000 bytes (though not repeat them that many times).
269        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
270        made it possible to implement the integer overflow checks in a much more
271        dynamic way, which I have now done. The artificial limitation on group
272        length has been removed - we now have only the limit on the total length of
273        the compiled pattern, which depends on the LINK_SIZE setting.
274    
275    10. Fixed a bug in the documentation for get/copy named substring when
276        duplicate names are permitted. If none of the named substrings are set, the
277        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
278        empty string.
279    
280    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
281        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
282        because the ] is interpreted as the first data character and the
283        terminating ] is not found. PCRE has been made compatible with Perl in this
284        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
285        cause memory overwriting.
286    
287    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
288        string has been matched (to stop an infinite loop). It was not recognizing
289        a conditional subpattern that could match an empty string if that
290        subpattern was within another subpattern. For example, it looped when
291        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
292        condition was not nested. This bug has been fixed.
293    
294    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
295        past the start of the subject in the presence of bytes with the top bit
296        set, for example "\x8aBCD".
297    
298    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
299        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
300    
301    14. Optimized (?!) to (*FAIL).
302    
303    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
304        This restricts code points to be within the range 0 to 0x10FFFF, excluding
305        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
306        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
307        does: it's just the validity check that is more restrictive.
308    
309    16. Inserted checks for integer overflows during escape sequence (backslash)
310        processing, and also fixed erroneous offset values for syntax errors during
311        backslash processing.
312    
313    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
314        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
315    
316    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
317        caused an overrun.
318    
319    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
320        something other than just ASCII characters) inside a group that had an
321        unlimited repeat caused a loop at compile time (while checking to see
322        whether the group could match an empty string).
323    
324    20. Debugging a pattern containing \p or \P could cause a crash. For example,
325        [\P{Any}] did so. (Error in the code for printing property names.)
326    
327    21. An orphan \E inside a character class could cause a crash.
328    
329    22. A repeated capturing bracket such as (A)? could cause a wild memory
330        reference during compilation.
331    
332    23. There are several functions in pcre_compile() that scan along a compiled
333        expression for various reasons (e.g. to see if it's fixed length for look
334        behind). There were bugs in these functions when a repeated \p or \P was
335        present in the pattern. These operators have additional parameters compared
336        with \d, etc, and these were not being taken into account when moving along
337        the compiled data. Specifically:
338    
339        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
340            length.
341    
342        (b) An item such as \pL+ within a repeated group could cause crashes or
343            loops.
344    
345        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
346            "reference to non-existent subpattern" error.
347    
348        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
349    
350    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
351        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
352    
353    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
354    
355    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
356        character were causing crashes (broken optimization).
357    
358    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
359        \p or \P) caused a compile-time loop.
360    
361    28. More problems have arisen in unanchored patterns when CRLF is a valid line
362        break. For example, the unstudied pattern [\r\n]A does not match the string
363        "\r\nA" because change 7.0/46 below moves the current point on by two
364        characters after failing to match at the start. However, the pattern \nA
365        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
366        the same is true. There doesn't seem any very clean way out of this, but
367        what I have chosen to do makes the common cases work: PCRE now takes note
368        of whether there can be an explicit match for \r or \n anywhere in the
369        pattern, and if so, 7.0/46 no longer applies. As part of this change,
370        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
371        pattern has explicit CR or LF references.
372    
373    29. Added (*CR) etc for changing newline setting at start of pattern.
374    
375    
376    Version 7.2 19-Jun-07
377    ---------------------
378    
379     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
380        which is apparently normally available under Windows.
381    
382     2. Re-jig the pcregrep tests with different newline settings in an attempt
383        to make them independent of the local environment's newline setting.
384    
385     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
386    
387     4. Some of the "internals" tests were previously cut out when the link size
388        was not 2, because the output contained actual offsets. The recent new
389        "Z" feature of pcretest means that these can be cut out, making the tests
390        usable with all link sizes.
391    
392     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
393        stack recursion. This gives a massive performance boost under BSD, but just
394        a small improvement under Linux. However, it saves one field in the frame
395        in all cases.
396    
397     6. Added more features from the forthcoming Perl 5.10:
398    
399        (a) (?-n) (where n is a string of digits) is a relative subroutine or
400            recursion call. It refers to the nth most recently opened parentheses.
401    
402        (b) (?+n) is also a relative subroutine call; it refers to the nth next
403            to be opened parentheses.
404    
405        (c) Conditions that refer to capturing parentheses can be specified
406            relatively, for example, (?(-2)... or (?(+3)...
407    
408        (d) \K resets the start of the current match so that everything before
409            is not part of it.
410    
411        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
412    
413        (f) \g{name} is another synonym - part of Perl 5.10's unification of
414            reference syntax.
415    
416        (g) (?| introduces a group in which the numbering of parentheses in each
417            alternative starts with the same number.
418    
419        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
420    
421     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
422        PCRE_INFO_JCHANGED.
423    
424     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
425        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
426        for detecting groups that can match an empty string.
427    
428     9. A pattern with a very large number of alternatives (more than several
429        hundred) was running out of internal workspace during the pre-compile
430        phase, where pcre_compile() figures out how much memory will be needed. A
431        bit of new cunning has reduced the workspace needed for groups with
432        alternatives. The 1000-alternative test pattern now uses 12 bytes of
433        workspace instead of running out of the 4096 that are available.
434    
435    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
436    
437    11. Applied patch from Google to remove an optimization that didn't quite work.
438        The report of the bug said:
439    
440          pcrecpp::RE("a*").FullMatch("aaa") matches, while
441          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
442          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
443    
444    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
445        it matched the wrong number of bytes.
446    
447    
448    Version 7.1 24-Apr-07
449    ---------------------
450    
451     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
452        that is more "standard", making use of automake and other Autotools. There
453        is some re-arrangement of the files and adjustment of comments consequent
454        on this.
455    
456     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
457        for recursive directory scanning broke on some systems because the files
458        are not scanned in any specific order and on different systems the order
459        was different. A call to "sort" has been inserted into RunGrepTest for the
460        approprate test as a short-term fix. In the longer term there may be an
461        alternative.
462    
463     3. I had an email from Eric Raymond about problems translating some of PCRE's
464        man pages to HTML (despite the fact that I distribute HTML pages, some
465        people do their own conversions for various reasons). The problems
466        concerned the use of low-level troff macros .br and .in. I have therefore
467        removed all such uses from the man pages (some were redundant, some could
468        be replaced by .nf/.fi pairs). The 132html script that I use to generate
469        HTML has been updated to handle .nf/.fi and to complain if it encounters
470        .br or .in.
471    
472     4. Updated comments in configure.ac that get placed in config.h.in and also
473        arranged for config.h to be included in the distribution, with the name
474        config.h.generic, for the benefit of those who have to compile without
475        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
476    
477     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
478        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
479        makevp.bat for the current PCRE, using the additional files
480        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
481    
482     6. A Windows user reported a minor discrepancy with test 2, which turned out
483        to be caused by a trailing space on an input line that had got lost in his
484        copy. The trailing space was an accident, so I've just removed it.
485    
486     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
487        that is needed.
488    
489     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
490        as "const" (a) because they are and (b) because it helps the PHP
491        maintainers who have recently made a script to detect big data structures
492        in the php code that should be moved to the .rodata section. I remembered
493        to update Builducptable as well, so it won't revert if ucptable.h is ever
494        re-created.
495    
496     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
497        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
498        order to be able to cut out the UTF-8 tables in the latter when UTF-8
499        support is not required. This saves 1.5-2K of code, which is important in
500        some applications.
501    
502        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
503        so as not to refer to the tables, even though these functions will never be
504        called when UTF-8 support is disabled. Otherwise there are problems with a
505        shared library.
506    
507    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
508    
509        (a) It was defining its arguments as char * instead of void *.
510    
511        (b) It was assuming that all moves were upwards in memory; this was true
512            a long time ago when I wrote it, but is no longer the case.
513    
514        The emulated memove() is provided for those environments that have neither
515        memmove() nor bcopy(). I didn't think anyone used it these days, but that
516        is clearly not the case, as these two bugs were recently reported.
517    
518    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
519        and Detrail to create the HTML documentation, the .txt form of the man
520        pages, and it removes trailing spaces from listed files. It also creates
521        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
522        case, it wraps all the #defines with #ifndefs. This script should be run
523        before "make dist".
524    
525    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
526        with Unicode property support.
527    
528        (a) For a maximizing quantifier, if the two different cases of the
529            character were of different lengths in their UTF-8 codings (there are
530            some cases like this - I found 11), and the matching function had to
531            back up over a mixture of the two cases, it incorrectly assumed they
532            were both the same length.
533    
534        (b) When PCRE was configured to use the heap rather than the stack for
535            recursion during matching, it was not correctly preserving the data for
536            the other case of a UTF-8 character when checking ahead for a match
537            while processing a minimizing repeat. If the check also involved
538            matching a wide character, but failed, corruption could cause an
539            erroneous result when trying to check for a repeat of the original
540            character.
541    
542    13. Some tidying changes to the testing mechanism:
543    
544        (a) The RunTest script now detects the internal link size and whether there
545            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
546            values substituted by "configure". (The RunGrepTest script already did
547            this for UTF-8.) The configure.ac script no longer substitutes the
548            relevant variables.
549    
550        (b) The debugging options /B and /D in pcretest show the compiled bytecode
551            with length and offset values. This means that the output is different
552            for different internal link sizes. Test 2 is skipped for link sizes
553            other than 2 because of this, bypassing the problem. Unfortunately,
554            there was also a test in test 3 (the locale tests) that used /B and
555            failed for link sizes other than 2. Rather than cut the whole test out,
556            I have added a new /Z option to pcretest that replaces the length and
557            offset values with spaces. This is now used to make test 3 independent
558            of link size. (Test 2 will be tidied up later.)
559    
560    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
561        segmentation fault instead of returning the appropriate error message.
562    
563    15. In multiline mode when the newline sequence was set to "any", the pattern
564        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
565        This doesn't seem right; it now treats the CRLF combination as the line
566        ending, and so does not match in that case. It's only a pattern such as ^$
567        that would hit this one: something like ^ABC$ would have failed after \r
568        and then tried again after \r\n.
569    
570    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
571        in an attempt to make files that differ only in their line terminators
572        compare equal. This works on Linux.
573    
574    17. Under certain error circumstances pcregrep might try to free random memory
575        as it exited. This is now fixed, thanks to valgrind.
576    
577    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
578        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
579        was because its rules for how to advance for /g after matching an empty
580        string at the end of a line did not allow for this case. They now check for
581        it specially.
582    
583    20. pcretest is supposed to handle patterns and data of any length, by
584        extending its buffers when necessary. It was getting this wrong when the
585        buffer for a data line had to be extended.
586    
587    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
588        CRLF as a newline sequence.
589    
590    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
591        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
592        I have nevertheless tidied it up.
593    
594    23. Added some casts to kill warnings from HP-UX ia64 compiler.
595    
596    24. Added a man page for pcre-config.
597    
598    
599    Version 7.0 19-Dec-06
600    ---------------------
601    
602     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
603        moving to gcc 4.1.1.
604    
605     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
606        sys/time.h, which is documented as needed for this function. It doesn't
607        seem to matter on Linux, but it showed up on some releases of OS X.
608    
609     3. It seems that there are systems where bytes whose values are greater than
610        127 match isprint() in the "C" locale. The "C" locale should be the
611        default when a C program starts up. In most systems, only ASCII printing
612        characters match isprint(). This difference caused the output from pcretest
613        to vary, making some of the tests fail. I have changed pcretest so that:
614    
615        (a) When it is outputting text in the compiled version of a pattern, bytes
616            other than 32-126 are always shown as hex escapes.
617    
618        (b) When it is outputting text that is a matched part of a subject string,
619            it does the same, unless a different locale has been set for the match
620            (using the /L modifier). In this case, it uses isprint() to decide.
621    
622     4. Fixed a major bug that caused incorrect computation of the amount of memory
623        required for a compiled pattern when options that changed within the
624        pattern affected the logic of the preliminary scan that determines the
625        length. The relevant options are -x, and -i in UTF-8 mode. The result was
626        that the computed length was too small. The symptoms of this bug were
627        either the PCRE error "internal error: code overflow" from pcre_compile(),
628        or a glibc crash with a message such as "pcretest: free(): invalid next
629        size (fast)". Examples of patterns that provoked this bug (shown in
630        pcretest format) are:
631    
632          /(?-x: )/x
633          /(?x)(?-x: \s*#\s*)/
634          /((?i)[\x{c0}])/8
635          /(?i:[\x{c0}])/8
636    
637        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
638        is now done differently.
639    
640     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
641        wrapper classes; (b) implement a new function in the C++ scanner that is
642        more efficient than the old way of doing things because it avoids levels of
643        recursion in the regex matching; (c) add a paragraph to the documentation
644        for the FullMatch() function.
645    
646     6. The escape sequence \n was being treated as whatever was defined as
647        "newline". Not only was this contrary to the documentation, which states
648        that \n is character 10 (hex 0A), but it also went horribly wrong when
649        "newline" was defined as CRLF. This has been fixed.
650    
651     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
652        was being set to -1 for the "end of line" case (supposedly a value that no
653        character can have). Though this value is never used (the check for end of
654        line is "zero bytes in current character"), it caused compiler complaints.
655        I've changed it to 0xffffffff.
656    
657     8. In pcre_version.c, the version string was being built by a sequence of
658        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
659        string (as it is for production releases) called a macro with an empty
660        argument. The C standard says the result of this is undefined. The gcc
661        compiler treats it as an empty string (which was what was wanted) but it is
662        reported that Visual C gives an error. The source has been hacked around to
663        avoid this problem.
664    
665     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
666        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
667        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
668        of them did).
669    
670    10. Originally, pcretest opened its input and output without "b"; then I was
671        told that "b" was needed in some environments, so it was added for release
672        5.0 to both the input and output. (It makes no difference on Unix-like
673        systems.) Later I was told that it is wrong for the input on Windows. I've
674        now abstracted the modes into two macros, to make it easier to fiddle with
675        them, and removed "b" from the input mode under Windows.
676    
677    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
678    
679    12. Added -help and --help to pcretest as an official way of being reminded
680        of the options.
681    
682    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
683        and pcrecpp.cc because they annoy compilers at high warning levels.
684    
685    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
686    
687    15. Fixed an occurrence of == in configure.ac that should have been = (shell
688        scripts are not C programs :-) and which was not noticed because it works
689        on Linux.
690    
691    16. pcretest is supposed to handle any length of pattern and data line (as one
692        line or as a continued sequence of lines) by extending its input buffer if
693        necessary. This feature was broken for very long pattern lines, leading to
694        a string of junk being passed to pcre_compile() if the pattern was longer
695        than about 50K.
696    
697    17. I have done a major re-factoring of the way pcre_compile() computes the
698        amount of memory needed for a compiled pattern. Previously, there was code
699        that made a preliminary scan of the pattern in order to do this. That was
700        OK when PCRE was new, but as the facilities have expanded, it has become
701        harder and harder to keep it in step with the real compile phase, and there
702        have been a number of bugs (see for example, 4 above). I have now found a
703        cunning way of running the real compile function in a "fake" mode that
704        enables it to compute how much memory it would need, while actually only
705        ever using a few hundred bytes of working memory and without too many
706        tests of the mode. This should make future maintenance and development
707        easier. A side effect of this work is that the limit of 200 on the nesting
708        depth of parentheses has been removed (though this was never a serious
709        limitation, I suspect). However, there is a downside: pcre_compile() now
710        runs more slowly than before (30% or more, depending on the pattern). I
711        hope this isn't a big issue. There is no effect on runtime performance.
712    
713    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
714        newline (only possible for the last line of a file) and it was a
715        pattern that set a locale (followed by /Lsomething), pcretest crashed.
716    
717    19. Added additional timing features to pcretest. (1) The -tm option now times
718        matching only, not compiling. (2) Both -t and -tm can be followed, as a
719        separate command line item, by a number that specifies the number of
720        repeats to use when timing. The default is 50000; this gives better
721        precision, but takes uncomfortably long for very large patterns.
722    
723    20. Extended pcre_study() to be more clever in cases where a branch of a
724        subpattern has no definite first character. For example, (a*|b*)[cd] would
725        previously give no result from pcre_study(). Now it recognizes that the
726        first character must be a, b, c, or d.
727    
728    21. There was an incorrect error "recursive call could loop indefinitely" if
729        a subpattern (or the entire pattern) that was being tested for matching an
730        empty string contained only one non-empty item after a nested subpattern.
731        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
732        incorrectly, because the \d was being skipped in the check.
733    
734    22. The pcretest program now has a new pattern option /B and a command line
735        option -b, which is equivalent to adding /B to every pattern. This causes
736        it to show the compiled bytecode, without the additional information that
737        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
738        is the same as /B/I).
739    
740    23. A new optimization is now able automatically to treat some sequences such
741        as a*b as a*+b. More specifically, if something simple (such as a character
742        or a simple class like \d) has an unlimited quantifier, and is followed by
743        something that cannot possibly match the quantified thing, the quantifier
744        is automatically "possessified".
745    
746    24. A recursive reference to a subpattern whose number was greater than 39
747        went wrong under certain circumstances in UTF-8 mode. This bug could also
748        have affected the operation of pcre_study().
749    
750    25. Realized that a little bit of performance could be had by replacing
751        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
752    
753    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
754    
755    27. Possessive quantifiers such as a++ were previously implemented by turning
756        them into atomic groups such as ($>a+). Now they have their own opcodes,
757        which improves performance. This includes the automatically created ones
758        from 23 above.
759    
760    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
761        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
762        the first matched character to be a colon. This applied both to named and
763        numbered groups.
764    
765    29. The ucpinternal.h header file was missing its idempotency #ifdef.
766    
767    30. I was sent a "project" file called libpcre.a.dev which I understand makes
768        building PCRE on Windows easier, so I have included it in the distribution.
769    
770    31. There is now a check in pcretest against a ridiculously large number being
771        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
772        loop, the loop is abandoned.
773    
774    32. Forward references to subpatterns in conditions such as (?(2)...) where
775        subpattern 2 is defined later cause pcre_compile() to search forwards in
776        the pattern for the relevant set of parentheses. This search went wrong
777        when there were unescaped parentheses in a character class, parentheses
778        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
779    
780    33. "Subroutine" calls and backreferences were previously restricted to
781        referencing subpatterns earlier in the regex. This restriction has now
782        been removed.
783    
784    34. Added a number of extra features that are going to be in Perl 5.10. On the
785        whole, these are just syntactic alternatives for features that PCRE had
786        previously implemented using the Python syntax or my own invention. The
787        other formats are all retained for compatibility.
788    
789        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
790            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
791            also .NET compatible.
792    
793        (b) A recursion or subroutine call to a named group can now be defined as
794            (?&name) as well as (?P>name).
795    
796        (c) A backreference to a named group can now be defined as \k<name> or
797            \k'name' as well as (?P=name). The new forms, as well as being in Perl
798            5.10, are also .NET compatible.
799    
800        (d) A conditional reference to a named group can now use the syntax
801            (?(<name>) or (?('name') as well as (?(name).
802    
803        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
804            groups (named and numbered) that are never evaluated inline, but can be
805            called as "subroutines" from elsewhere. In effect, the DEFINE condition
806            is always false. There may be only one alternative in such a group.
807    
808        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
809            as the simple (?(R). The condition is true only if the most recent
810            recursion is that of the given number or name. It does not search out
811            through the entire recursion stack.
812    
813        (g) The escape \gN or \g{N} has been added, where N is a positive or
814            negative number, specifying an absolute or relative reference.
815    
816    35. Tidied to get rid of some further signed/unsigned compiler warnings and
817        some "unreachable code" warnings.
818    
819    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
820        things, this adds five new scripts.
821    
822    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
823        There were also incompatibilities regarding the handling of \Q..\E inside
824        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
825        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
826    
827    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
828        matches an empty string, and forcibly breaks the loop. There were bugs in
829        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
830        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
831        separate and independent bugs (that affected different cases) have been
832        fixed.
833    
834    39. Refactored the code to abolish the use of different opcodes for small
835        capturing bracket numbers. This is a tidy that I avoided doing when I
836        removed the limit on the number of capturing brackets for 3.5 back in 2001.
837        The new approach is not only tidier, it makes it possible to reduce the
838        memory needed to fix the previous bug (38).
839    
840    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
841        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
842        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
843        mode.
844    
845    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
846        report.
847    
848    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
849        copy construction and assignment in the C++ wrapper.
850    
851    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
852        couple of bugs that could have given wrong results in the "--newline=crlf"
853        case.
854    
855    44. Added a number of casts and did some reorganization of signed/unsigned int
856        variables following suggestions from Dair Grant. Also renamed the variable
857        "this" as "item" because it is a C++ keyword.
858    
859    45. Arranged for dftables to add
860    
861          #include "pcre_internal.h"
862    
863        to pcre_chartables.c because without it, gcc 4.x may remove the array
864        definition from the final binary if PCRE is built into a static library and
865        dead code stripping is activated.
866    
867    46. For an unanchored pattern, if a match attempt fails at the start of a
868        newline sequence, and the newline setting is CRLF or ANY, and the next two
869        characters are CRLF, advance by two characters instead of one.
870    
871    
872    Version 6.7 04-Jul-06
873    ---------------------
874    
875     1. In order to handle tests when input lines are enormously long, pcretest has
876        been re-factored so that it automatically extends its buffers when
877        necessary. The code is crude, but this _is_ just a test program. The
878        default size has been increased from 32K to 50K.
879    
880     2. The code in pcre_study() was using the value of the re argument before
881        testing it for NULL. (Of course, in any sensible call of the function, it
882        won't be NULL.)
883    
884     3. The memmove() emulation function in pcre_internal.h, which is used on
885        systems that lack both memmove() and bcopy() - that is, hardly ever -
886        was missing a "static" storage class specifier.
887    
888     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
889        containing an extended class (one that cannot be represented by a bitmap
890        because it contains high-valued characters or Unicode property items, e.g.
891        [\pZ]). Almost always one would set UTF-8 mode when processing such a
892        pattern, but PCRE should not loop if you do not (it no longer does).
893        [Detail: two cases were found: (a) a repeated subpattern containing an
894        extended class; (b) a recursive reference to a subpattern that followed a
895        previous extended class. It wasn't skipping over the extended class
896        correctly when UTF-8 mode was not set.]
897    
898     5. A negated single-character class was not being recognized as fixed-length
899        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
900        compile error "lookbehind assertion is not fixed length".
901    
902     6. The RunPerlTest auxiliary script was showing an unexpected difference
903        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
904        write a Perl script that can interpret lines of an input file either as
905        byte characters or as UTF-8, which is what "perltest" was being required to
906        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
907        can't do is switch easily at run time between having the "use utf8;" pragma
908        or not. In the end, I fudged it by using the RunPerlTest script to insert
909        "use utf8;" explicitly for the UTF-8 tests.
910    
911     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
912        the end of the subject string, contrary to the documentation and to what
913        Perl does. This was true of both matching functions. Now it matches only at
914        the start of the subject and immediately after *internal* newlines.
915    
916     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
917        a pointer to an int instead of a pointer to an unsigned long int. This
918        caused problems on 64-bit systems.
919    
920     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
921        instance of the 'standard' template library not being so standard".
922    
923    10. There was no check on the number of named subpatterns nor the maximum
924        length of a subpattern name. The product of these values is used to compute
925        the size of the memory block for a compiled pattern. By supplying a very
926        long subpattern name and a large number of named subpatterns, the size
927        computation could be caused to overflow. This is now prevented by limiting
928        the length of names to 32 characters, and the number of named subpatterns
929        to 10,000.
930    
931    11. Subpatterns that are repeated with specific counts have to be replicated in
932        the compiled pattern. The size of memory for this was computed from the
933        length of the subpattern and the repeat count. The latter is limited to
934        65535, but there was no limit on the former, meaning that integer overflow
935        could in principle occur. The compiled length of a repeated subpattern is
936        now limited to 30,000 bytes in order to prevent this.
937    
938    12. Added the optional facility to have named substrings with the same name.
939    
940    13. Added the ability to use a named substring as a condition, using the
941        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
942        are numbers (not recommended). Forward references are permitted.
943    
944    14. Added forward references in named backreferences (if you see what I mean).
945    
946    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
947        pattern could run off the end of the subject. For example, the pattern
948        "(?s)(.{1,5})"8 did this with the subject "ab".
949    
950    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
951        PCRE_CASELESS was set when matching characters that were quantified with ?
952        or *.
953    
954    17. A character class other than a single negated character that had a minimum
955        but no maximum quantifier - for example [ab]{6,} - was not handled
956        correctly by pce_dfa_exec(). It would match only one character.
957    
958    18. A valid (though odd) pattern that looked like a POSIX character
959        class but used an invalid character after [ (for example [[,abc,]]) caused
960        pcre_compile() to give the error "Failed: internal error: code overflow" or
961        in some cases to crash with a glibc free() error. This could even happen if
962        the pattern terminated after [[ but there just happened to be a sequence of
963        letters, a binary zero, and a closing ] in the memory that followed.
964    
965    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
966        over the years. Originally (before any Unicode support), just the bottom 8
967        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
968        output from "man perlunicode" includes this:
969    
970          The regular expression compiler produces polymorphic opcodes.  That
971          is, the pattern adapts to the data and automatically switches to
972          the Unicode character scheme when presented with Unicode data--or
973          instead uses a traditional byte scheme when presented with byte
974          data.
975    
976        Sadly, a wide octal escape does not cause a switch, and in a string with
977        no other multibyte characters, these octal escapes are treated as before.
978        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
979        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
980        Unicode string.
981    
982        I have not perpetrated such confusion in PCRE. Up till now, it took just
983        the bottom 8 bits, as in old Perl. I have now made octal escapes with
984        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
985        translate to the appropriate multibyte character.
986    
987    29. Applied some refactoring to reduce the number of warnings from Microsoft
988        and Borland compilers. This has included removing the fudge introduced
989        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
990        a warning about an unused variable.
991    
992    21. PCRE has not included VT (character 0x0b) in the set of whitespace
993        characters since release 4.0, because Perl (from release 5.004) does not.
994        [Or at least, is documented not to: some releases seem to be in conflict
995        with the documentation.] However, when a pattern was studied with
996        pcre_study() and all its branches started with \s, PCRE still included VT
997        as a possible starting character. Of course, this did no harm; it just
998        caused an unnecessary match attempt.
999    
1000    22. Removed a now-redundant internal flag bit that recorded the fact that case
1001        dependency changed within the pattern. This was once needed for "required
1002        byte" processing, but is no longer used. This recovers a now-scarce options
1003        bit. Also moved the least significant internal flag bit to the most-
1004        significant bit of the word, which was not previously used (hangover from
1005        the days when it was an int rather than a uint) to free up another bit for
1006        the future.
1007    
1008    23. Added support for CRLF line endings as well as CR and LF. As well as the
1009        default being selectable at build time, it can now be changed at runtime
1010        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1011        specify that it is scanning data with non-default line endings.
1012    
1013    24. Changed the definition of CXXLINK to make it agree with the definition of
1014        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1015    
1016    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1017        recursions. This makes a big different to stack usage for some patterns.
1018    
1019    26. If a subpattern containing a named recursion or subroutine reference such
1020        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1021        the space required for the compiled pattern went wrong and gave too small a
1022        value. Depending on the environment, this could lead to "Failed: internal
1023        error: code overflow at offset 49" or "glibc detected double free or
1024        corruption" errors.
1025    
1026    27. Applied patches from Google (a) to support the new newline modes and (b) to
1027        advance over multibyte UTF-8 characters in GlobalReplace.
1028    
1029    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1030        difference for some implementation of PCRE in some Windows version.
1031    
1032    29. Added some extra testing facilities to pcretest:
1033    
1034        \q<number>   in a data line sets the "match limit" value
1035        \Q<number>   in a data line sets the "match recursion limt" value
1036        -S <number>  sets the stack size, where <number> is in megabytes
1037    
1038        The -S option isn't available for Windows.
1039    
1040    
1041    Version 6.6 06-Feb-06
1042    ---------------------
1043    
1044     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1045        in pcreposix.h. I have copied the definition from pcre.h.
1046    
1047     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1048        because pcre.h is no longer a built file.
1049    
1050     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1051        not normally included in the compiled code.
1052    
1053    
1054    Version 6.5 01-Feb-06
1055    ---------------------
1056    
1057     1. When using the partial match feature with pcre_dfa_exec(), it was not
1058        anchoring the second and subsequent partial matches at the new starting
1059        point. This could lead to incorrect results. For example, with the pattern
1060        /1234/, partially matching against "123" and then "a4" gave a match.
1061    
1062     2. Changes to pcregrep:
1063    
1064        (a) All non-match returns from pcre_exec() were being treated as failures
1065            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1066            error message is output. Some extra information is given for the
1067            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1068            probably the only errors that are likely to be caused by users (by
1069            specifying a regex that has nested indefinite repeats, for instance).
1070            If there are more than 20 of these errors, pcregrep is abandoned.
1071    
1072        (b) A binary zero was treated as data while matching, but terminated the
1073            output line if it was written out. This has been fixed: binary zeroes
1074            are now no different to any other data bytes.
1075    
1076        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1077            used to set a locale for matching. The --locale=xxxx long option has
1078            been added (no short equivalent) to specify a locale explicitly on the
1079            pcregrep command, overriding the environment variables.
1080    
1081        (d) When -B was used with -n, some line numbers in the output were one less
1082            than they should have been.
1083    
1084        (e) Added the -o (--only-matching) option.
1085    
1086        (f) If -A or -C was used with -c (count only), some lines of context were
1087            accidentally printed for the final match.
1088    
1089        (g) Added the -H (--with-filename) option.
1090    
1091        (h) The combination of options -rh failed to suppress file names for files
1092            that were found from directory arguments.
1093    
1094        (i) Added the -D (--devices) and -d (--directories) options.
1095    
1096        (j) Added the -F (--fixed-strings) option.
1097    
1098        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1099    
1100        (l) Added the --colo(u)r option.
1101    
1102        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1103            is not present by default.
1104    
1105     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1106        items such as (?R) or (?1), when the recursion could match a number of
1107        alternatives. If it matched one of the alternatives, but subsequently,
1108        outside the recursion, there was a failure, the code tried to back up into
1109        the recursion. However, because of the way PCRE is implemented, this is not
1110        possible, and the result was an incorrect result from the match.
1111    
1112        In order to prevent this happening, the specification of recursion has
1113        been changed so that all such subpatterns are automatically treated as
1114        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1115    
1116     4. I had overlooked the fact that, in some locales, there are characters for
1117        which isalpha() is true but neither isupper() nor islower() are true. In
1118        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1119        and ordfeminine) are like this. This affected the treatment of \w and \W
1120        when they appeared in character classes, but not when they appeared outside
1121        a character class. The bit map for "word" characters is now created
1122        separately from the results of isalnum() instead of just taking it from the
1123        upper, lower, and digit maps. (Plus the underscore character, of course.)
1124    
1125     5. The above bug also affected the handling of POSIX character classes such as
1126        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1127        permanent tables. Instead, the bit maps for such a class were previously
1128        created as the appropriate unions of the upper, lower, and digit bitmaps.
1129        Now they are created by subtraction from the [[:word:]] class, which has
1130        its own bitmap.
1131    
1132     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1133        It is created by subtracting the vertical space characters (\x09, \x0a,
1134        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1135        subtraction was done in the overall bitmap for a character class, meaning
1136        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1137        be recognized. This bug has been fixed.
1138    
1139     7. Patches from the folks at Google:
1140    
1141          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1142          real life, but is still worth protecting against".
1143    
1144          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1145          regular expressions".
1146    
1147          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1148          have it.
1149    
1150          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1151          "configure" and the latter not, in order to fix a problem somebody had
1152          with compiling the Arg class on HP-UX.
1153    
1154          (e) Improve the error-handling of the C++ wrapper a little bit.
1155    
1156          (f) New tests for checking recursion limiting.
1157    
1158     8. The pcre_memmove() function, which is used only if the environment does not
1159        have a standard memmove() function (and is therefore rarely compiled),
1160        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1161        returning a result (though PCRE never actually uses the result).
1162    
1163     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1164        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1165        returned instead of calling malloc() with an overflowing number that would
1166        most likely cause subsequent chaos.
1167    
1168    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1169    
1170    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1171        with this option is matched, the nmatch and pmatch options of regexec() are
1172        ignored.
1173    
1174    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1175        provided in case anyone wants to the the POSIX interface with UTF-8
1176        strings.
1177    
1178    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1179        C++ linking (needed for some HP-UX environments).
1180    
1181    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1182        (unused parameter) and in the pcre_printint() function (omitted "default"
1183        switch label when the default is to do nothing).
1184    
1185    15. Added some code to make it possible, when PCRE is compiled as a C++
1186        library, to replace subject pointers for pcre_exec() with a smart pointer
1187        class, thus making it possible to process discontinuous strings.
1188    
1189    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1190        much the same function. They were added by different people who were trying
1191        to make PCRE easy to compile on non-Unix systems. It has been suggested
1192        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1193        for compiling on Windows systems. I have therefore replaced it with
1194        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1195        defaults to "extern" for C or "extern C" for C++, which works fine on
1196        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1197        SCOPE with something explicit in config.h. In addition:
1198    
1199        (a) pcreposix.h still had just "extern" instead of either of these macros;
1200            I have replaced it with PCRE_DATA_SCOPE.
1201    
1202        (b) Functions such as _pcre_xclass(), which are internal to the library,
1203            but external in the C sense, all had PCRE_EXPORT in their definitions.
1204            This is apparently wrong for the Windows case, so I have removed it.
1205            (It makes no difference on Unix-like systems.)
1206    
1207    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1208        of recursive calls to match(). This is different to MATCH_LIMIT because
1209        that limits the total number of calls to match(), not all of which increase
1210        the depth of recursion. Limiting the recursion depth limits the amount of
1211        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1212        when PCRE is compiled, and changed at run time. A patch from Google adds
1213        this functionality to the C++ interface.
1214    
1215    18. Changes to the handling of Unicode character properties:
1216    
1217        (a) Updated the table to Unicode 4.1.0.
1218    
1219        (b) Recognize characters that are not in the table as "Cn" (undefined).
1220    
1221        (c) I revised the way the table is implemented to a much improved format
1222            which includes recognition of ranges. It now supports the ranges that
1223            are defined in UnicodeData.txt, and it also amalgamates other
1224            characters into ranges. This has reduced the number of entries in the
1225            table from around 16,000 to around 3,000, thus reducing its size
1226            considerably. I realized I did not need to use a tree structure after
1227            all - a binary chop search is just as efficient. Having reduced the
1228            number of entries, I extended their size from 6 bytes to 8 bytes to
1229            allow for more data.
1230    
1231        (d) Added support for Unicode script names via properties such as \p{Han}.
1232    
1233    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1234        matching that character.
1235    
1236    20. When matching a repeated Unicode property with a minimum greater than zero,
1237        (for example \pL{2,}), PCRE could look past the end of the subject if it
1238        reached it while seeking the minimum number of characters. This could
1239        happen only if some of the characters were more than one byte long, because
1240        there is a check for at least the minimum number of bytes.
1241    
1242    21. Refactored the implementation of \p and \P so as to be more general, to
1243        allow for more different types of property in future. This has changed the
1244        compiled form incompatibly. Anybody with saved compiled patterns that use
1245        \p or \P will have to recompile them.
1246    
1247    22. Added "Any" and "L&" to the supported property types.
1248    
1249    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1250        but give a compile time error if the value is greater than 0xff.
1251    
1252    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1253        accidentally not being installed or uninstalled.
1254    
1255    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1256        made were to insert the current release number. This seemed silly, because
1257        it made things harder for people building PCRE on systems that don't run
1258        "configure". I have turned pcre.h into a distributed file, no longer built
1259        by "configure", with the version identification directly included. There is
1260        no longer a pcre.h.in file.
1261    
1262        However, this change necessitated a change to the pcre-config script as
1263        well. It is built from pcre-config.in, and one of the substitutions was the
1264        release number. I have updated configure.ac so that ./configure now finds
1265        the release number by grepping pcre.h.
1266    
1267    26. Added the ability to run the tests under valgrind.
1268    
1269    
1270    Version 6.4 05-Sep-05
1271    ---------------------
1272    
1273     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1274        "--" to be printed when multiple files were scanned, even when none of the
1275        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1276        consider it to be a bug, and have restored the previous behaviour.
1277    
1278     2. A couple of code tidies to get rid of compiler warnings.
1279    
1280     3. The pcretest program used to cheat by referring to symbols in the library
1281        whose names begin with _pcre_. These are internal symbols that are not
1282        really supposed to be visible externally, and in some environments it is
1283        possible to suppress them. The cheating is now confined to including
1284        certain files from the library's source, which is a bit cleaner.
1285    
1286     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1287        file's purpose clearer.
1288    
1289     5. Reorganized pcre_ucp_findchar().
1290    
1291    
1292    Version 6.3 15-Aug-05
1293    ---------------------
1294    
1295     1. The file libpcre.pc.in did not have general read permission in the tarball.
1296    
1297     2. There were some problems when building without C++ support:
1298    
1299        (a) If C++ support was not built, "make install" and "make test" still
1300            tried to test it.
1301    
1302        (b) There were problems when the value of CXX was explicitly set. Some
1303            changes have been made to try to fix these, and ...
1304    
1305        (c) --disable-cpp can now be used to explicitly disable C++ support.
1306    
1307        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1308            backslash in a target when C++ was disabled. This confuses some
1309            versions of "make", apparently. Using an intermediate variable solves
1310            this. (Same for CPP_LOBJ.)
1311    
1312     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1313        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1314        necessary on certain architectures.
1315    
1316     4. Added a setting of -export-symbols-regex to the link command to remove
1317        those symbols that are exported in the C sense, but actually are local
1318        within the library, and not documented. Their names all begin with
1319        "_pcre_". This is not a perfect job, because (a) we have to except some
1320        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1321        available (and never for static libraries). I have made a note to try to
1322        find a way round (a) in the future.
1323    
1324    
1325    Version 6.2 01-Aug-05
1326    ---------------------
1327    
1328     1. There was no test for integer overflow of quantifier values. A construction
1329        such as {1111111111111111} would give undefined results. What is worse, if
1330        a minimum quantifier for a parenthesized subpattern overflowed and became
1331        negative, the calculation of the memory size went wrong. This could have
1332        led to memory overwriting.
1333    
1334     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1335    
1336     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1337        operating environments where this matters.
1338    
1339     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1340        PCRE options from within the C++ wrapper.
1341    
1342     5. Named capturing subpatterns were not being correctly counted when a pattern
1343        was compiled. This caused two problems: (a) If there were more than 100
1344        such subpatterns, the calculation of the memory needed for the whole
1345        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1346        back references of the form \12, where the number was greater than 9, were
1347        not recognized as back references, even though there were sufficient
1348        previous subpatterns.
1349    
1350     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1351        versions of gcc, e.g. 2.95.4.
1352    
1353    
1354  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1355  ---------------------  ---------------------
1356    

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