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revision 81 by nigel, Sat Feb 24 21:40:59 2007 UTC revision 321 by ph10, Wed Mar 5 17:10:45 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.7 05-Mar-08
5    ---------------------
6    
7    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
8        a string to a long long, pretend we don't even have a long long." This is
9        done by checking for the strtoq, strtoll, and _strtoi64 functions.
10    
11    
12    Version 7.6 28-Jan-08
13    ---------------------
14    
15    1.  A character class containing a very large number of characters with
16        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
17        overflow.
18    
19    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
20        HAVE_LONG_LONG is not defined.
21    
22    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
23        bring them up to date and include new features. This patch includes:
24    
25        - Fixed PH's badly added libz and libbz2 support.
26        - Fixed a problem with static linking.
27        - Added pcredemo. [But later removed - see 7 below.]
28        - Fixed dftables problem and added an option.
29        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
30            HAVE_LONG_LONG.
31        - Added readline support for pcretest.
32        - Added an listing of the option settings after cmake has run.
33    
34    4.  A user submitted a patch to Makefile that makes it easy to create
35        "pcre.dll" under mingw when using Configure/Make. I added stuff to
36        Makefile.am that cause it to include this special target, without
37        affecting anything else. Note that the same mingw target plus all
38        the other distribution libraries and programs are now supported
39        when configuring with CMake (see 6 below) instead of with
40        Configure/Make.
41    
42    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
43        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
44        exported in the Windows port". It has not yet been confirmed that the patch
45        solves the problem, but it does no harm.
46    
47    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
48        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
49        with CMake, and also correct the comment about stack recursion.
50    
51    7.  Remove the automatic building of pcredemo from the ./configure system and
52        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
53        of a program that users should build themselves after PCRE is installed, so
54        building it automatically is not really right. What is more, it gave
55        trouble in some build environments.
56    
57    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
58    
59    
60    Version 7.5 10-Jan-08
61    ---------------------
62    
63    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
64        values in parens when parsing an RE using the C++ wrapper."
65    
66    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
67        Characters greater than 255 were excluded from the class instead of being
68        included.
69    
70    3.  The same bug as (2) above applied to negated POSIX classes such as
71        [:^space:].
72    
73    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
74        defined or documented. It seems to have been a typo for PCRE_STATIC, so
75        I have changed it.
76    
77    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
78        first named subpattern) and a construct such as (?&a) would reference the
79        first named subpattern whose name started with "a" (in other words, the
80        length check was missing). Both these problems are fixed. "Subpattern name
81        expected" is now given for (?&) (a zero-length name), and this patch also
82        makes it give the same error for \k'' (previously it complained that that
83        was a reference to a non-existent subpattern).
84    
85    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
86        this is right because (?- can be followed by option settings as well as by
87        digits. I have, however, made the messages clearer.
88    
89    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
90        than the number used in the conditional) now cause a compile-time error.
91        This is actually not compatible with Perl, which accepts such patterns, but
92        treats the conditional as always being FALSE (as PCRE used to), but it
93        seems to me that giving a diagnostic is better.
94    
95    8.  Change "alphameric" to the more common word "alphanumeric" in comments
96        and messages.
97    
98    9.  Fix two occurrences of "backslash" in comments that should have been
99        "backspace".
100    
101    10. Remove two redundant lines of code that can never be obeyed (their function
102        was moved elsewhere).
103    
104    11. The program that makes PCRE's Unicode character property table had a bug
105        which caused it to generate incorrect table entries for sequences of
106        characters that have the same character type, but are in different scripts.
107        It amalgamated them into a single range, with the script of the first of
108        them. In other words, some characters were in the wrong script. There were
109        thirteen such cases, affecting characters in the following ranges:
110    
111          U+002b0 - U+002c1
112          U+0060c - U+0060d
113          U+0061e - U+00612
114          U+0064b - U+0065e
115          U+0074d - U+0076d
116          U+01800 - U+01805
117          U+01d00 - U+01d77
118          U+01d9b - U+01dbf
119          U+0200b - U+0200f
120          U+030fc - U+030fe
121          U+03260 - U+0327f
122          U+0fb46 - U+0fbb1
123          U+10450 - U+1049d
124    
125    12. The -o option (show only the matching part of a line) for pcregrep was not
126        compatible with GNU grep in that, if there was more than one match in a
127        line, it showed only the first of them. It now behaves in the same way as
128        GNU grep.
129    
130    13. If the -o and -v options were combined for pcregrep, it printed a blank
131        line for every non-matching line. GNU grep prints nothing, and pcregrep now
132        does the same. The return code can be used to tell if there were any
133        non-matching lines.
134    
135    14. Added --file-offsets and --line-offsets to pcregrep.
136    
137    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
138        infinitely looping recursion. The bug was that positive lookaheads were not
139        being skipped when checking for a possible empty match (negative lookaheads
140        and both kinds of lookbehind were skipped).
141    
142    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
143        inclusion of <windows.h> to before rather than after the definition of
144        INVALID_FILE_ATTRIBUTES (patch from David Byron).
145    
146    17. Specifying a possessive quantifier with a specific limit for a Unicode
147        character property caused pcre_compile() to compile bad code, which led at
148        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
149        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
150        caused the error; without that there was no problem.
151    
152    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
153    
154    19. Added --enable-pcretest-libreadline.
155    
156    20. In pcrecpp.cc, the variable 'count' was incremented twice in
157        RE::GlobalReplace(). As a result, the number of replacements returned was
158        double what it should be. I removed one of the increments, but Craig sent a
159        later patch that removed the other one (the right fix) and added unit tests
160        that check the return values (which was not done before).
161    
162    21. Several CMake things:
163    
164        (1) Arranged that, when cmake is used on Unix, the libraries end up with
165            the names libpcre and libpcreposix, not just pcre and pcreposix.
166    
167        (2) The above change means that pcretest and pcregrep are now correctly
168            linked with the newly-built libraries, not previously installed ones.
169    
170        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
171    
172    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
173        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
174        UTF-8 newline character). The key issue is that the pattern starts .*;
175        this means that the match must be either at the beginning, or after a
176        newline. The bug was in the code for advancing after a failed match and
177        checking that the new position followed a newline. It was not taking
178        account of UTF-8 characters correctly.
179    
180    23. PCRE was behaving differently from Perl in the way it recognized POSIX
181        character classes. PCRE was not treating the sequence [:...:] as a
182        character class unless the ... were all letters. Perl, however, seems to
183        allow any characters between [: and :], though of course it rejects as
184        unknown any "names" that contain non-letters, because all the known class
185        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
186        for example, whereas PCRE did not - it did not recognize a POSIX character
187        class. This seemed a bit dangerous, so the code has been changed to be
188        closer to Perl. The behaviour is not identical to Perl, because PCRE will
189        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
190        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
191        Perl does, and where it didn't before.
192    
193    24. Rewrite so as to remove the single use of %n from pcregrep because in some
194        Windows environments %n is disabled by default.
195    
196    
197    Version 7.4 21-Sep-07
198    ---------------------
199    
200    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
201        means that a class such as [\s] counted as "explicit reference to CR or
202        LF". That isn't really right - the whole point of the change was to try to
203        help when there was an actual mention of one of the two characters. So now
204        the change happens only if \r or \n (or a literal CR or LF) character is
205        encountered.
206    
207    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
208        of both had grown to the point where there were only 3 bits left.
209        Fortunately, there was spare space in the data structure, and so I have
210        moved the internal flags into a new 16-bit field to free up more option
211        bits.
212    
213    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
214        but did not set the internal JCHANGED flag - either of these is enough to
215        control the way the "get" function works - but the PCRE_INFO_JCHANGED
216        facility is supposed to tell if (?J) was ever used, so now (?J) at the
217        start sets both bits.
218    
219    4.  Added options (at build time, compile time, exec time) to change \R from
220        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
221    
222    5.  doc/pcresyntax.html was missing from the distribution.
223    
224    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
225        compatibility, even though it is no longer used.
226    
227    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
228        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
229        windows.h file is present (where different names are used). [This was
230        reversed later after testing - see 16 below.]
231    
232    8.  Changed all #include <config.h> to #include "config.h". There were also
233        some further <pcre.h> cases that I changed to "pcre.h".
234    
235    9.  When pcregrep was used with the --colour option, it missed the line ending
236        sequence off the lines that it output.
237    
238    10. It was pointed out to me that arrays of string pointers cause lots of
239        relocations when a shared library is dynamically loaded. A technique of
240        using a single long string with a table of offsets can drastically reduce
241        these. I have refactored PCRE in four places to do this. The result is
242        dramatic:
243    
244          Originally:                          290
245          After changing UCP table:            187
246          After changing error message table:   43
247          After changing table of "verbs"       36
248          After changing table of Posix names   22
249    
250        Thanks to the folks working on Gregex for glib for this insight.
251    
252    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
253        unicode-properties was also set.
254    
255    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
256    
257    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
258        checked only for CRLF.
259    
260    14. Added casts to pcretest.c to avoid compiler warnings.
261    
262    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
263    
264    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
265        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
266        entirely. This removes changes made in 7 above.
267    
268    17. The CMake files have been updated, and there is now more information about
269        building with CMake in the NON-UNIX-USE document.
270    
271    
272    Version 7.3 28-Aug-07
273    ---------------------
274    
275     1. In the rejigging of the build system that eventually resulted in 7.1, the
276        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
277        brackets there is not right, since it causes compilers to look for an
278        installed pcre.h, not the version that is in the source that is being
279        compiled (which of course may be different). I have changed it back to:
280    
281          #include "pcre.h"
282    
283        I have a vague recollection that the change was concerned with compiling in
284        different directories, but in the new build system, that is taken care of
285        by the VPATH setting the Makefile.
286    
287     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
288        when the subject happened to end in the byte 0x85 (e.g. if the last
289        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
290        characters but of course it shouldn't be taken as a newline when it is part
291        of another character. The bug was that, for an unlimited repeat of . in
292        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
293        characters when looking for a newline.
294    
295     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
296    
297     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
298        in debug output.
299    
300     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
301        long printing in the pcrecpp unittest when running under MinGW.
302    
303     6. ESC_K was left out of the EBCDIC table.
304    
305     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
306        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
307        limit also applies to "virtual nesting" when a pattern is recursive, and in
308        this case 1000 isn't so big. I have been able to remove this limit at the
309        expense of backing off one optimization in certain circumstances. Normally,
310        when pcre_exec() would call its internal match() function recursively and
311        immediately return the result unconditionally, it uses a "tail recursion"
312        feature to save stack. However, when a subpattern that can match an empty
313        string has an unlimited repetition quantifier, it no longer makes this
314        optimization. That gives it a stack frame in which to save the data for
315        checking that an empty string has been matched. Previously this was taken
316        from the 1000-entry workspace that had been reserved. So now there is no
317        explicit limit, but more stack is used.
318    
319     8. Applied Daniel's patches to solve problems with the import/export magic
320        syntax that is required for Windows, and which was going wrong for the
321        pcreposix and pcrecpp parts of the library. These were overlooked when this
322        problem was solved for the main library.
323    
324     9. There were some crude static tests to avoid integer overflow when computing
325        the size of patterns that contain repeated groups with explicit upper
326        limits. As the maximum quantifier is 65535, the maximum group length was
327        set at 30,000 so that the product of these two numbers did not overflow a
328        32-bit integer. However, it turns out that people want to use groups that
329        are longer than 30,000 bytes (though not repeat them that many times).
330        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
331        made it possible to implement the integer overflow checks in a much more
332        dynamic way, which I have now done. The artificial limitation on group
333        length has been removed - we now have only the limit on the total length of
334        the compiled pattern, which depends on the LINK_SIZE setting.
335    
336    10. Fixed a bug in the documentation for get/copy named substring when
337        duplicate names are permitted. If none of the named substrings are set, the
338        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
339        empty string.
340    
341    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
342        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
343        because the ] is interpreted as the first data character and the
344        terminating ] is not found. PCRE has been made compatible with Perl in this
345        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
346        cause memory overwriting.
347    
348    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
349        string has been matched (to stop an infinite loop). It was not recognizing
350        a conditional subpattern that could match an empty string if that
351        subpattern was within another subpattern. For example, it looped when
352        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
353        condition was not nested. This bug has been fixed.
354    
355    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
356        past the start of the subject in the presence of bytes with the top bit
357        set, for example "\x8aBCD".
358    
359    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
360        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
361    
362    14. Optimized (?!) to (*FAIL).
363    
364    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
365        This restricts code points to be within the range 0 to 0x10FFFF, excluding
366        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
367        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
368        does: it's just the validity check that is more restrictive.
369    
370    16. Inserted checks for integer overflows during escape sequence (backslash)
371        processing, and also fixed erroneous offset values for syntax errors during
372        backslash processing.
373    
374    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
375        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
376    
377    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
378        caused an overrun.
379    
380    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
381        something other than just ASCII characters) inside a group that had an
382        unlimited repeat caused a loop at compile time (while checking to see
383        whether the group could match an empty string).
384    
385    20. Debugging a pattern containing \p or \P could cause a crash. For example,
386        [\P{Any}] did so. (Error in the code for printing property names.)
387    
388    21. An orphan \E inside a character class could cause a crash.
389    
390    22. A repeated capturing bracket such as (A)? could cause a wild memory
391        reference during compilation.
392    
393    23. There are several functions in pcre_compile() that scan along a compiled
394        expression for various reasons (e.g. to see if it's fixed length for look
395        behind). There were bugs in these functions when a repeated \p or \P was
396        present in the pattern. These operators have additional parameters compared
397        with \d, etc, and these were not being taken into account when moving along
398        the compiled data. Specifically:
399    
400        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
401            length.
402    
403        (b) An item such as \pL+ within a repeated group could cause crashes or
404            loops.
405    
406        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
407            "reference to non-existent subpattern" error.
408    
409        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
410    
411    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
412        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
413    
414    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
415    
416    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
417        character were causing crashes (broken optimization).
418    
419    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
420        \p or \P) caused a compile-time loop.
421    
422    28. More problems have arisen in unanchored patterns when CRLF is a valid line
423        break. For example, the unstudied pattern [\r\n]A does not match the string
424        "\r\nA" because change 7.0/46 below moves the current point on by two
425        characters after failing to match at the start. However, the pattern \nA
426        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
427        the same is true. There doesn't seem any very clean way out of this, but
428        what I have chosen to do makes the common cases work: PCRE now takes note
429        of whether there can be an explicit match for \r or \n anywhere in the
430        pattern, and if so, 7.0/46 no longer applies. As part of this change,
431        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
432        pattern has explicit CR or LF references.
433    
434    29. Added (*CR) etc for changing newline setting at start of pattern.
435    
436    
437    Version 7.2 19-Jun-07
438    ---------------------
439    
440     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
441        which is apparently normally available under Windows.
442    
443     2. Re-jig the pcregrep tests with different newline settings in an attempt
444        to make them independent of the local environment's newline setting.
445    
446     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
447    
448     4. Some of the "internals" tests were previously cut out when the link size
449        was not 2, because the output contained actual offsets. The recent new
450        "Z" feature of pcretest means that these can be cut out, making the tests
451        usable with all link sizes.
452    
453     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
454        stack recursion. This gives a massive performance boost under BSD, but just
455        a small improvement under Linux. However, it saves one field in the frame
456        in all cases.
457    
458     6. Added more features from the forthcoming Perl 5.10:
459    
460        (a) (?-n) (where n is a string of digits) is a relative subroutine or
461            recursion call. It refers to the nth most recently opened parentheses.
462    
463        (b) (?+n) is also a relative subroutine call; it refers to the nth next
464            to be opened parentheses.
465    
466        (c) Conditions that refer to capturing parentheses can be specified
467            relatively, for example, (?(-2)... or (?(+3)...
468    
469        (d) \K resets the start of the current match so that everything before
470            is not part of it.
471    
472        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
473    
474        (f) \g{name} is another synonym - part of Perl 5.10's unification of
475            reference syntax.
476    
477        (g) (?| introduces a group in which the numbering of parentheses in each
478            alternative starts with the same number.
479    
480        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
481    
482     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
483        PCRE_INFO_JCHANGED.
484    
485     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
486        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
487        for detecting groups that can match an empty string.
488    
489     9. A pattern with a very large number of alternatives (more than several
490        hundred) was running out of internal workspace during the pre-compile
491        phase, where pcre_compile() figures out how much memory will be needed. A
492        bit of new cunning has reduced the workspace needed for groups with
493        alternatives. The 1000-alternative test pattern now uses 12 bytes of
494        workspace instead of running out of the 4096 that are available.
495    
496    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
497    
498    11. Applied patch from Google to remove an optimization that didn't quite work.
499        The report of the bug said:
500    
501          pcrecpp::RE("a*").FullMatch("aaa") matches, while
502          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
503          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
504    
505    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
506        it matched the wrong number of bytes.
507    
508    
509    Version 7.1 24-Apr-07
510    ---------------------
511    
512     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
513        that is more "standard", making use of automake and other Autotools. There
514        is some re-arrangement of the files and adjustment of comments consequent
515        on this.
516    
517     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
518        for recursive directory scanning broke on some systems because the files
519        are not scanned in any specific order and on different systems the order
520        was different. A call to "sort" has been inserted into RunGrepTest for the
521        approprate test as a short-term fix. In the longer term there may be an
522        alternative.
523    
524     3. I had an email from Eric Raymond about problems translating some of PCRE's
525        man pages to HTML (despite the fact that I distribute HTML pages, some
526        people do their own conversions for various reasons). The problems
527        concerned the use of low-level troff macros .br and .in. I have therefore
528        removed all such uses from the man pages (some were redundant, some could
529        be replaced by .nf/.fi pairs). The 132html script that I use to generate
530        HTML has been updated to handle .nf/.fi and to complain if it encounters
531        .br or .in.
532    
533     4. Updated comments in configure.ac that get placed in config.h.in and also
534        arranged for config.h to be included in the distribution, with the name
535        config.h.generic, for the benefit of those who have to compile without
536        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
537    
538     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
539        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
540        makevp.bat for the current PCRE, using the additional files
541        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
542    
543     6. A Windows user reported a minor discrepancy with test 2, which turned out
544        to be caused by a trailing space on an input line that had got lost in his
545        copy. The trailing space was an accident, so I've just removed it.
546    
547     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
548        that is needed.
549    
550     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
551        as "const" (a) because they are and (b) because it helps the PHP
552        maintainers who have recently made a script to detect big data structures
553        in the php code that should be moved to the .rodata section. I remembered
554        to update Builducptable as well, so it won't revert if ucptable.h is ever
555        re-created.
556    
557     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
558        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
559        order to be able to cut out the UTF-8 tables in the latter when UTF-8
560        support is not required. This saves 1.5-2K of code, which is important in
561        some applications.
562    
563        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
564        so as not to refer to the tables, even though these functions will never be
565        called when UTF-8 support is disabled. Otherwise there are problems with a
566        shared library.
567    
568    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
569    
570        (a) It was defining its arguments as char * instead of void *.
571    
572        (b) It was assuming that all moves were upwards in memory; this was true
573            a long time ago when I wrote it, but is no longer the case.
574    
575        The emulated memove() is provided for those environments that have neither
576        memmove() nor bcopy(). I didn't think anyone used it these days, but that
577        is clearly not the case, as these two bugs were recently reported.
578    
579    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
580        and Detrail to create the HTML documentation, the .txt form of the man
581        pages, and it removes trailing spaces from listed files. It also creates
582        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
583        case, it wraps all the #defines with #ifndefs. This script should be run
584        before "make dist".
585    
586    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
587        with Unicode property support.
588    
589        (a) For a maximizing quantifier, if the two different cases of the
590            character were of different lengths in their UTF-8 codings (there are
591            some cases like this - I found 11), and the matching function had to
592            back up over a mixture of the two cases, it incorrectly assumed they
593            were both the same length.
594    
595        (b) When PCRE was configured to use the heap rather than the stack for
596            recursion during matching, it was not correctly preserving the data for
597            the other case of a UTF-8 character when checking ahead for a match
598            while processing a minimizing repeat. If the check also involved
599            matching a wide character, but failed, corruption could cause an
600            erroneous result when trying to check for a repeat of the original
601            character.
602    
603    13. Some tidying changes to the testing mechanism:
604    
605        (a) The RunTest script now detects the internal link size and whether there
606            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
607            values substituted by "configure". (The RunGrepTest script already did
608            this for UTF-8.) The configure.ac script no longer substitutes the
609            relevant variables.
610    
611        (b) The debugging options /B and /D in pcretest show the compiled bytecode
612            with length and offset values. This means that the output is different
613            for different internal link sizes. Test 2 is skipped for link sizes
614            other than 2 because of this, bypassing the problem. Unfortunately,
615            there was also a test in test 3 (the locale tests) that used /B and
616            failed for link sizes other than 2. Rather than cut the whole test out,
617            I have added a new /Z option to pcretest that replaces the length and
618            offset values with spaces. This is now used to make test 3 independent
619            of link size. (Test 2 will be tidied up later.)
620    
621    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
622        segmentation fault instead of returning the appropriate error message.
623    
624    15. In multiline mode when the newline sequence was set to "any", the pattern
625        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
626        This doesn't seem right; it now treats the CRLF combination as the line
627        ending, and so does not match in that case. It's only a pattern such as ^$
628        that would hit this one: something like ^ABC$ would have failed after \r
629        and then tried again after \r\n.
630    
631    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
632        in an attempt to make files that differ only in their line terminators
633        compare equal. This works on Linux.
634    
635    17. Under certain error circumstances pcregrep might try to free random memory
636        as it exited. This is now fixed, thanks to valgrind.
637    
638    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
639        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
640        was because its rules for how to advance for /g after matching an empty
641        string at the end of a line did not allow for this case. They now check for
642        it specially.
643    
644    20. pcretest is supposed to handle patterns and data of any length, by
645        extending its buffers when necessary. It was getting this wrong when the
646        buffer for a data line had to be extended.
647    
648    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
649        CRLF as a newline sequence.
650    
651    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
652        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
653        I have nevertheless tidied it up.
654    
655    23. Added some casts to kill warnings from HP-UX ia64 compiler.
656    
657    24. Added a man page for pcre-config.
658    
659    
660    Version 7.0 19-Dec-06
661    ---------------------
662    
663     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
664        moving to gcc 4.1.1.
665    
666     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
667        sys/time.h, which is documented as needed for this function. It doesn't
668        seem to matter on Linux, but it showed up on some releases of OS X.
669    
670     3. It seems that there are systems where bytes whose values are greater than
671        127 match isprint() in the "C" locale. The "C" locale should be the
672        default when a C program starts up. In most systems, only ASCII printing
673        characters match isprint(). This difference caused the output from pcretest
674        to vary, making some of the tests fail. I have changed pcretest so that:
675    
676        (a) When it is outputting text in the compiled version of a pattern, bytes
677            other than 32-126 are always shown as hex escapes.
678    
679        (b) When it is outputting text that is a matched part of a subject string,
680            it does the same, unless a different locale has been set for the match
681            (using the /L modifier). In this case, it uses isprint() to decide.
682    
683     4. Fixed a major bug that caused incorrect computation of the amount of memory
684        required for a compiled pattern when options that changed within the
685        pattern affected the logic of the preliminary scan that determines the
686        length. The relevant options are -x, and -i in UTF-8 mode. The result was
687        that the computed length was too small. The symptoms of this bug were
688        either the PCRE error "internal error: code overflow" from pcre_compile(),
689        or a glibc crash with a message such as "pcretest: free(): invalid next
690        size (fast)". Examples of patterns that provoked this bug (shown in
691        pcretest format) are:
692    
693          /(?-x: )/x
694          /(?x)(?-x: \s*#\s*)/
695          /((?i)[\x{c0}])/8
696          /(?i:[\x{c0}])/8
697    
698        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
699        is now done differently.
700    
701     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
702        wrapper classes; (b) implement a new function in the C++ scanner that is
703        more efficient than the old way of doing things because it avoids levels of
704        recursion in the regex matching; (c) add a paragraph to the documentation
705        for the FullMatch() function.
706    
707     6. The escape sequence \n was being treated as whatever was defined as
708        "newline". Not only was this contrary to the documentation, which states
709        that \n is character 10 (hex 0A), but it also went horribly wrong when
710        "newline" was defined as CRLF. This has been fixed.
711    
712     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
713        was being set to -1 for the "end of line" case (supposedly a value that no
714        character can have). Though this value is never used (the check for end of
715        line is "zero bytes in current character"), it caused compiler complaints.
716        I've changed it to 0xffffffff.
717    
718     8. In pcre_version.c, the version string was being built by a sequence of
719        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
720        string (as it is for production releases) called a macro with an empty
721        argument. The C standard says the result of this is undefined. The gcc
722        compiler treats it as an empty string (which was what was wanted) but it is
723        reported that Visual C gives an error. The source has been hacked around to
724        avoid this problem.
725    
726     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
727        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
728        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
729        of them did).
730    
731    10. Originally, pcretest opened its input and output without "b"; then I was
732        told that "b" was needed in some environments, so it was added for release
733        5.0 to both the input and output. (It makes no difference on Unix-like
734        systems.) Later I was told that it is wrong for the input on Windows. I've
735        now abstracted the modes into two macros, to make it easier to fiddle with
736        them, and removed "b" from the input mode under Windows.
737    
738    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
739    
740    12. Added -help and --help to pcretest as an official way of being reminded
741        of the options.
742    
743    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
744        and pcrecpp.cc because they annoy compilers at high warning levels.
745    
746    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
747    
748    15. Fixed an occurrence of == in configure.ac that should have been = (shell
749        scripts are not C programs :-) and which was not noticed because it works
750        on Linux.
751    
752    16. pcretest is supposed to handle any length of pattern and data line (as one
753        line or as a continued sequence of lines) by extending its input buffer if
754        necessary. This feature was broken for very long pattern lines, leading to
755        a string of junk being passed to pcre_compile() if the pattern was longer
756        than about 50K.
757    
758    17. I have done a major re-factoring of the way pcre_compile() computes the
759        amount of memory needed for a compiled pattern. Previously, there was code
760        that made a preliminary scan of the pattern in order to do this. That was
761        OK when PCRE was new, but as the facilities have expanded, it has become
762        harder and harder to keep it in step with the real compile phase, and there
763        have been a number of bugs (see for example, 4 above). I have now found a
764        cunning way of running the real compile function in a "fake" mode that
765        enables it to compute how much memory it would need, while actually only
766        ever using a few hundred bytes of working memory and without too many
767        tests of the mode. This should make future maintenance and development
768        easier. A side effect of this work is that the limit of 200 on the nesting
769        depth of parentheses has been removed (though this was never a serious
770        limitation, I suspect). However, there is a downside: pcre_compile() now
771        runs more slowly than before (30% or more, depending on the pattern). I
772        hope this isn't a big issue. There is no effect on runtime performance.
773    
774    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
775        newline (only possible for the last line of a file) and it was a
776        pattern that set a locale (followed by /Lsomething), pcretest crashed.
777    
778    19. Added additional timing features to pcretest. (1) The -tm option now times
779        matching only, not compiling. (2) Both -t and -tm can be followed, as a
780        separate command line item, by a number that specifies the number of
781        repeats to use when timing. The default is 50000; this gives better
782        precision, but takes uncomfortably long for very large patterns.
783    
784    20. Extended pcre_study() to be more clever in cases where a branch of a
785        subpattern has no definite first character. For example, (a*|b*)[cd] would
786        previously give no result from pcre_study(). Now it recognizes that the
787        first character must be a, b, c, or d.
788    
789    21. There was an incorrect error "recursive call could loop indefinitely" if
790        a subpattern (or the entire pattern) that was being tested for matching an
791        empty string contained only one non-empty item after a nested subpattern.
792        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
793        incorrectly, because the \d was being skipped in the check.
794    
795    22. The pcretest program now has a new pattern option /B and a command line
796        option -b, which is equivalent to adding /B to every pattern. This causes
797        it to show the compiled bytecode, without the additional information that
798        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
799        is the same as /B/I).
800    
801    23. A new optimization is now able automatically to treat some sequences such
802        as a*b as a*+b. More specifically, if something simple (such as a character
803        or a simple class like \d) has an unlimited quantifier, and is followed by
804        something that cannot possibly match the quantified thing, the quantifier
805        is automatically "possessified".
806    
807    24. A recursive reference to a subpattern whose number was greater than 39
808        went wrong under certain circumstances in UTF-8 mode. This bug could also
809        have affected the operation of pcre_study().
810    
811    25. Realized that a little bit of performance could be had by replacing
812        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
813    
814    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
815    
816    27. Possessive quantifiers such as a++ were previously implemented by turning
817        them into atomic groups such as ($>a+). Now they have their own opcodes,
818        which improves performance. This includes the automatically created ones
819        from 23 above.
820    
821    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
822        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
823        the first matched character to be a colon. This applied both to named and
824        numbered groups.
825    
826    29. The ucpinternal.h header file was missing its idempotency #ifdef.
827    
828    30. I was sent a "project" file called libpcre.a.dev which I understand makes
829        building PCRE on Windows easier, so I have included it in the distribution.
830    
831    31. There is now a check in pcretest against a ridiculously large number being
832        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
833        loop, the loop is abandoned.
834    
835    32. Forward references to subpatterns in conditions such as (?(2)...) where
836        subpattern 2 is defined later cause pcre_compile() to search forwards in
837        the pattern for the relevant set of parentheses. This search went wrong
838        when there were unescaped parentheses in a character class, parentheses
839        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
840    
841    33. "Subroutine" calls and backreferences were previously restricted to
842        referencing subpatterns earlier in the regex. This restriction has now
843        been removed.
844    
845    34. Added a number of extra features that are going to be in Perl 5.10. On the
846        whole, these are just syntactic alternatives for features that PCRE had
847        previously implemented using the Python syntax or my own invention. The
848        other formats are all retained for compatibility.
849    
850        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
851            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
852            also .NET compatible.
853    
854        (b) A recursion or subroutine call to a named group can now be defined as
855            (?&name) as well as (?P>name).
856    
857        (c) A backreference to a named group can now be defined as \k<name> or
858            \k'name' as well as (?P=name). The new forms, as well as being in Perl
859            5.10, are also .NET compatible.
860    
861        (d) A conditional reference to a named group can now use the syntax
862            (?(<name>) or (?('name') as well as (?(name).
863    
864        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
865            groups (named and numbered) that are never evaluated inline, but can be
866            called as "subroutines" from elsewhere. In effect, the DEFINE condition
867            is always false. There may be only one alternative in such a group.
868    
869        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
870            as the simple (?(R). The condition is true only if the most recent
871            recursion is that of the given number or name. It does not search out
872            through the entire recursion stack.
873    
874        (g) The escape \gN or \g{N} has been added, where N is a positive or
875            negative number, specifying an absolute or relative reference.
876    
877    35. Tidied to get rid of some further signed/unsigned compiler warnings and
878        some "unreachable code" warnings.
879    
880    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
881        things, this adds five new scripts.
882    
883    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
884        There were also incompatibilities regarding the handling of \Q..\E inside
885        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
886        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
887    
888    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
889        matches an empty string, and forcibly breaks the loop. There were bugs in
890        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
891        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
892        separate and independent bugs (that affected different cases) have been
893        fixed.
894    
895    39. Refactored the code to abolish the use of different opcodes for small
896        capturing bracket numbers. This is a tidy that I avoided doing when I
897        removed the limit on the number of capturing brackets for 3.5 back in 2001.
898        The new approach is not only tidier, it makes it possible to reduce the
899        memory needed to fix the previous bug (38).
900    
901    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
902        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
903        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
904        mode.
905    
906    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
907        report.
908    
909    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
910        copy construction and assignment in the C++ wrapper.
911    
912    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
913        couple of bugs that could have given wrong results in the "--newline=crlf"
914        case.
915    
916    44. Added a number of casts and did some reorganization of signed/unsigned int
917        variables following suggestions from Dair Grant. Also renamed the variable
918        "this" as "item" because it is a C++ keyword.
919    
920    45. Arranged for dftables to add
921    
922          #include "pcre_internal.h"
923    
924        to pcre_chartables.c because without it, gcc 4.x may remove the array
925        definition from the final binary if PCRE is built into a static library and
926        dead code stripping is activated.
927    
928    46. For an unanchored pattern, if a match attempt fails at the start of a
929        newline sequence, and the newline setting is CRLF or ANY, and the next two
930        characters are CRLF, advance by two characters instead of one.
931    
932    
933    Version 6.7 04-Jul-06
934    ---------------------
935    
936     1. In order to handle tests when input lines are enormously long, pcretest has
937        been re-factored so that it automatically extends its buffers when
938        necessary. The code is crude, but this _is_ just a test program. The
939        default size has been increased from 32K to 50K.
940    
941     2. The code in pcre_study() was using the value of the re argument before
942        testing it for NULL. (Of course, in any sensible call of the function, it
943        won't be NULL.)
944    
945     3. The memmove() emulation function in pcre_internal.h, which is used on
946        systems that lack both memmove() and bcopy() - that is, hardly ever -
947        was missing a "static" storage class specifier.
948    
949     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
950        containing an extended class (one that cannot be represented by a bitmap
951        because it contains high-valued characters or Unicode property items, e.g.
952        [\pZ]). Almost always one would set UTF-8 mode when processing such a
953        pattern, but PCRE should not loop if you do not (it no longer does).
954        [Detail: two cases were found: (a) a repeated subpattern containing an
955        extended class; (b) a recursive reference to a subpattern that followed a
956        previous extended class. It wasn't skipping over the extended class
957        correctly when UTF-8 mode was not set.]
958    
959     5. A negated single-character class was not being recognized as fixed-length
960        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
961        compile error "lookbehind assertion is not fixed length".
962    
963     6. The RunPerlTest auxiliary script was showing an unexpected difference
964        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
965        write a Perl script that can interpret lines of an input file either as
966        byte characters or as UTF-8, which is what "perltest" was being required to
967        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
968        can't do is switch easily at run time between having the "use utf8;" pragma
969        or not. In the end, I fudged it by using the RunPerlTest script to insert
970        "use utf8;" explicitly for the UTF-8 tests.
971    
972     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
973        the end of the subject string, contrary to the documentation and to what
974        Perl does. This was true of both matching functions. Now it matches only at
975        the start of the subject and immediately after *internal* newlines.
976    
977     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
978        a pointer to an int instead of a pointer to an unsigned long int. This
979        caused problems on 64-bit systems.
980    
981     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
982        instance of the 'standard' template library not being so standard".
983    
984    10. There was no check on the number of named subpatterns nor the maximum
985        length of a subpattern name. The product of these values is used to compute
986        the size of the memory block for a compiled pattern. By supplying a very
987        long subpattern name and a large number of named subpatterns, the size
988        computation could be caused to overflow. This is now prevented by limiting
989        the length of names to 32 characters, and the number of named subpatterns
990        to 10,000.
991    
992    11. Subpatterns that are repeated with specific counts have to be replicated in
993        the compiled pattern. The size of memory for this was computed from the
994        length of the subpattern and the repeat count. The latter is limited to
995        65535, but there was no limit on the former, meaning that integer overflow
996        could in principle occur. The compiled length of a repeated subpattern is
997        now limited to 30,000 bytes in order to prevent this.
998    
999    12. Added the optional facility to have named substrings with the same name.
1000    
1001    13. Added the ability to use a named substring as a condition, using the
1002        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1003        are numbers (not recommended). Forward references are permitted.
1004    
1005    14. Added forward references in named backreferences (if you see what I mean).
1006    
1007    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1008        pattern could run off the end of the subject. For example, the pattern
1009        "(?s)(.{1,5})"8 did this with the subject "ab".
1010    
1011    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1012        PCRE_CASELESS was set when matching characters that were quantified with ?
1013        or *.
1014    
1015    17. A character class other than a single negated character that had a minimum
1016        but no maximum quantifier - for example [ab]{6,} - was not handled
1017        correctly by pce_dfa_exec(). It would match only one character.
1018    
1019    18. A valid (though odd) pattern that looked like a POSIX character
1020        class but used an invalid character after [ (for example [[,abc,]]) caused
1021        pcre_compile() to give the error "Failed: internal error: code overflow" or
1022        in some cases to crash with a glibc free() error. This could even happen if
1023        the pattern terminated after [[ but there just happened to be a sequence of
1024        letters, a binary zero, and a closing ] in the memory that followed.
1025    
1026    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1027        over the years. Originally (before any Unicode support), just the bottom 8
1028        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1029        output from "man perlunicode" includes this:
1030    
1031          The regular expression compiler produces polymorphic opcodes.  That
1032          is, the pattern adapts to the data and automatically switches to
1033          the Unicode character scheme when presented with Unicode data--or
1034          instead uses a traditional byte scheme when presented with byte
1035          data.
1036    
1037        Sadly, a wide octal escape does not cause a switch, and in a string with
1038        no other multibyte characters, these octal escapes are treated as before.
1039        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1040        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1041        Unicode string.
1042    
1043        I have not perpetrated such confusion in PCRE. Up till now, it took just
1044        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1045        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1046        translate to the appropriate multibyte character.
1047    
1048    29. Applied some refactoring to reduce the number of warnings from Microsoft
1049        and Borland compilers. This has included removing the fudge introduced
1050        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1051        a warning about an unused variable.
1052    
1053    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1054        characters since release 4.0, because Perl (from release 5.004) does not.
1055        [Or at least, is documented not to: some releases seem to be in conflict
1056        with the documentation.] However, when a pattern was studied with
1057        pcre_study() and all its branches started with \s, PCRE still included VT
1058        as a possible starting character. Of course, this did no harm; it just
1059        caused an unnecessary match attempt.
1060    
1061    22. Removed a now-redundant internal flag bit that recorded the fact that case
1062        dependency changed within the pattern. This was once needed for "required
1063        byte" processing, but is no longer used. This recovers a now-scarce options
1064        bit. Also moved the least significant internal flag bit to the most-
1065        significant bit of the word, which was not previously used (hangover from
1066        the days when it was an int rather than a uint) to free up another bit for
1067        the future.
1068    
1069    23. Added support for CRLF line endings as well as CR and LF. As well as the
1070        default being selectable at build time, it can now be changed at runtime
1071        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1072        specify that it is scanning data with non-default line endings.
1073    
1074    24. Changed the definition of CXXLINK to make it agree with the definition of
1075        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1076    
1077    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1078        recursions. This makes a big different to stack usage for some patterns.
1079    
1080    26. If a subpattern containing a named recursion or subroutine reference such
1081        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1082        the space required for the compiled pattern went wrong and gave too small a
1083        value. Depending on the environment, this could lead to "Failed: internal
1084        error: code overflow at offset 49" or "glibc detected double free or
1085        corruption" errors.
1086    
1087    27. Applied patches from Google (a) to support the new newline modes and (b) to
1088        advance over multibyte UTF-8 characters in GlobalReplace.
1089    
1090    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1091        difference for some implementation of PCRE in some Windows version.
1092    
1093    29. Added some extra testing facilities to pcretest:
1094    
1095        \q<number>   in a data line sets the "match limit" value
1096        \Q<number>   in a data line sets the "match recursion limt" value
1097        -S <number>  sets the stack size, where <number> is in megabytes
1098    
1099        The -S option isn't available for Windows.
1100    
1101    
1102    Version 6.6 06-Feb-06
1103    ---------------------
1104    
1105     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1106        in pcreposix.h. I have copied the definition from pcre.h.
1107    
1108     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1109        because pcre.h is no longer a built file.
1110    
1111     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1112        not normally included in the compiled code.
1113    
1114    
1115    Version 6.5 01-Feb-06
1116    ---------------------
1117    
1118     1. When using the partial match feature with pcre_dfa_exec(), it was not
1119        anchoring the second and subsequent partial matches at the new starting
1120        point. This could lead to incorrect results. For example, with the pattern
1121        /1234/, partially matching against "123" and then "a4" gave a match.
1122    
1123     2. Changes to pcregrep:
1124    
1125        (a) All non-match returns from pcre_exec() were being treated as failures
1126            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1127            error message is output. Some extra information is given for the
1128            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1129            probably the only errors that are likely to be caused by users (by
1130            specifying a regex that has nested indefinite repeats, for instance).
1131            If there are more than 20 of these errors, pcregrep is abandoned.
1132    
1133        (b) A binary zero was treated as data while matching, but terminated the
1134            output line if it was written out. This has been fixed: binary zeroes
1135            are now no different to any other data bytes.
1136    
1137        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1138            used to set a locale for matching. The --locale=xxxx long option has
1139            been added (no short equivalent) to specify a locale explicitly on the
1140            pcregrep command, overriding the environment variables.
1141    
1142        (d) When -B was used with -n, some line numbers in the output were one less
1143            than they should have been.
1144    
1145        (e) Added the -o (--only-matching) option.
1146    
1147        (f) If -A or -C was used with -c (count only), some lines of context were
1148            accidentally printed for the final match.
1149    
1150        (g) Added the -H (--with-filename) option.
1151    
1152        (h) The combination of options -rh failed to suppress file names for files
1153            that were found from directory arguments.
1154    
1155        (i) Added the -D (--devices) and -d (--directories) options.
1156    
1157        (j) Added the -F (--fixed-strings) option.
1158    
1159        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1160    
1161        (l) Added the --colo(u)r option.
1162    
1163        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1164            is not present by default.
1165    
1166     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1167        items such as (?R) or (?1), when the recursion could match a number of
1168        alternatives. If it matched one of the alternatives, but subsequently,
1169        outside the recursion, there was a failure, the code tried to back up into
1170        the recursion. However, because of the way PCRE is implemented, this is not
1171        possible, and the result was an incorrect result from the match.
1172    
1173        In order to prevent this happening, the specification of recursion has
1174        been changed so that all such subpatterns are automatically treated as
1175        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1176    
1177     4. I had overlooked the fact that, in some locales, there are characters for
1178        which isalpha() is true but neither isupper() nor islower() are true. In
1179        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1180        and ordfeminine) are like this. This affected the treatment of \w and \W
1181        when they appeared in character classes, but not when they appeared outside
1182        a character class. The bit map for "word" characters is now created
1183        separately from the results of isalnum() instead of just taking it from the
1184        upper, lower, and digit maps. (Plus the underscore character, of course.)
1185    
1186     5. The above bug also affected the handling of POSIX character classes such as
1187        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1188        permanent tables. Instead, the bit maps for such a class were previously
1189        created as the appropriate unions of the upper, lower, and digit bitmaps.
1190        Now they are created by subtraction from the [[:word:]] class, which has
1191        its own bitmap.
1192    
1193     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1194        It is created by subtracting the vertical space characters (\x09, \x0a,
1195        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1196        subtraction was done in the overall bitmap for a character class, meaning
1197        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1198        be recognized. This bug has been fixed.
1199    
1200     7. Patches from the folks at Google:
1201    
1202          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1203          real life, but is still worth protecting against".
1204    
1205          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1206          regular expressions".
1207    
1208          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1209          have it.
1210    
1211          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1212          "configure" and the latter not, in order to fix a problem somebody had
1213          with compiling the Arg class on HP-UX.
1214    
1215          (e) Improve the error-handling of the C++ wrapper a little bit.
1216    
1217          (f) New tests for checking recursion limiting.
1218    
1219     8. The pcre_memmove() function, which is used only if the environment does not
1220        have a standard memmove() function (and is therefore rarely compiled),
1221        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1222        returning a result (though PCRE never actually uses the result).
1223    
1224     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1225        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1226        returned instead of calling malloc() with an overflowing number that would
1227        most likely cause subsequent chaos.
1228    
1229    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1230    
1231    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1232        with this option is matched, the nmatch and pmatch options of regexec() are
1233        ignored.
1234    
1235    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1236        provided in case anyone wants to the the POSIX interface with UTF-8
1237        strings.
1238    
1239    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1240        C++ linking (needed for some HP-UX environments).
1241    
1242    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1243        (unused parameter) and in the pcre_printint() function (omitted "default"
1244        switch label when the default is to do nothing).
1245    
1246    15. Added some code to make it possible, when PCRE is compiled as a C++
1247        library, to replace subject pointers for pcre_exec() with a smart pointer
1248        class, thus making it possible to process discontinuous strings.
1249    
1250    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1251        much the same function. They were added by different people who were trying
1252        to make PCRE easy to compile on non-Unix systems. It has been suggested
1253        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1254        for compiling on Windows systems. I have therefore replaced it with
1255        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1256        defaults to "extern" for C or "extern C" for C++, which works fine on
1257        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1258        SCOPE with something explicit in config.h. In addition:
1259    
1260        (a) pcreposix.h still had just "extern" instead of either of these macros;
1261            I have replaced it with PCRE_DATA_SCOPE.
1262    
1263        (b) Functions such as _pcre_xclass(), which are internal to the library,
1264            but external in the C sense, all had PCRE_EXPORT in their definitions.
1265            This is apparently wrong for the Windows case, so I have removed it.
1266            (It makes no difference on Unix-like systems.)
1267    
1268    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1269        of recursive calls to match(). This is different to MATCH_LIMIT because
1270        that limits the total number of calls to match(), not all of which increase
1271        the depth of recursion. Limiting the recursion depth limits the amount of
1272        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1273        when PCRE is compiled, and changed at run time. A patch from Google adds
1274        this functionality to the C++ interface.
1275    
1276    18. Changes to the handling of Unicode character properties:
1277    
1278        (a) Updated the table to Unicode 4.1.0.
1279    
1280        (b) Recognize characters that are not in the table as "Cn" (undefined).
1281    
1282        (c) I revised the way the table is implemented to a much improved format
1283            which includes recognition of ranges. It now supports the ranges that
1284            are defined in UnicodeData.txt, and it also amalgamates other
1285            characters into ranges. This has reduced the number of entries in the
1286            table from around 16,000 to around 3,000, thus reducing its size
1287            considerably. I realized I did not need to use a tree structure after
1288            all - a binary chop search is just as efficient. Having reduced the
1289            number of entries, I extended their size from 6 bytes to 8 bytes to
1290            allow for more data.
1291    
1292        (d) Added support for Unicode script names via properties such as \p{Han}.
1293    
1294    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1295        matching that character.
1296    
1297    20. When matching a repeated Unicode property with a minimum greater than zero,
1298        (for example \pL{2,}), PCRE could look past the end of the subject if it
1299        reached it while seeking the minimum number of characters. This could
1300        happen only if some of the characters were more than one byte long, because
1301        there is a check for at least the minimum number of bytes.
1302    
1303    21. Refactored the implementation of \p and \P so as to be more general, to
1304        allow for more different types of property in future. This has changed the
1305        compiled form incompatibly. Anybody with saved compiled patterns that use
1306        \p or \P will have to recompile them.
1307    
1308    22. Added "Any" and "L&" to the supported property types.
1309    
1310    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1311        but give a compile time error if the value is greater than 0xff.
1312    
1313    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1314        accidentally not being installed or uninstalled.
1315    
1316    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1317        made were to insert the current release number. This seemed silly, because
1318        it made things harder for people building PCRE on systems that don't run
1319        "configure". I have turned pcre.h into a distributed file, no longer built
1320        by "configure", with the version identification directly included. There is
1321        no longer a pcre.h.in file.
1322    
1323        However, this change necessitated a change to the pcre-config script as
1324        well. It is built from pcre-config.in, and one of the substitutions was the
1325        release number. I have updated configure.ac so that ./configure now finds
1326        the release number by grepping pcre.h.
1327    
1328    26. Added the ability to run the tests under valgrind.
1329    
1330    
1331    Version 6.4 05-Sep-05
1332    ---------------------
1333    
1334     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1335        "--" to be printed when multiple files were scanned, even when none of the
1336        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1337        consider it to be a bug, and have restored the previous behaviour.
1338    
1339     2. A couple of code tidies to get rid of compiler warnings.
1340    
1341     3. The pcretest program used to cheat by referring to symbols in the library
1342        whose names begin with _pcre_. These are internal symbols that are not
1343        really supposed to be visible externally, and in some environments it is
1344        possible to suppress them. The cheating is now confined to including
1345        certain files from the library's source, which is a bit cleaner.
1346    
1347     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1348        file's purpose clearer.
1349    
1350     5. Reorganized pcre_ucp_findchar().
1351    
1352    
1353    Version 6.3 15-Aug-05
1354    ---------------------
1355    
1356     1. The file libpcre.pc.in did not have general read permission in the tarball.
1357    
1358     2. There were some problems when building without C++ support:
1359    
1360        (a) If C++ support was not built, "make install" and "make test" still
1361            tried to test it.
1362    
1363        (b) There were problems when the value of CXX was explicitly set. Some
1364            changes have been made to try to fix these, and ...
1365    
1366        (c) --disable-cpp can now be used to explicitly disable C++ support.
1367    
1368        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1369            backslash in a target when C++ was disabled. This confuses some
1370            versions of "make", apparently. Using an intermediate variable solves
1371            this. (Same for CPP_LOBJ.)
1372    
1373     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1374        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1375        necessary on certain architectures.
1376    
1377     4. Added a setting of -export-symbols-regex to the link command to remove
1378        those symbols that are exported in the C sense, but actually are local
1379        within the library, and not documented. Their names all begin with
1380        "_pcre_". This is not a perfect job, because (a) we have to except some
1381        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1382        available (and never for static libraries). I have made a note to try to
1383        find a way round (a) in the future.
1384    
1385    
1386  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
1387  ---------------------  ---------------------
1388    

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