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revision 81 by nigel, Sat Feb 24 21:40:59 2007 UTC revision 325 by ph10, Sat Mar 8 17:13:02 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    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12        pre-7.6 versions, which defined a global no_arg variable instead of putting
13        it in the RE class.
14    
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
17    
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
19    
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
22    
23        (2) If there was more than one level of directory, the subdirectories were
24            skipped unless they satisfied the include/exclude conditions. This is
25            inconsistent with GNU grep (and could even be seen as contrary to the
26            pcregrep specification - which I improved to make it absolutely clear).
27            The action now is always to scan all levels of directory, and just
28            apply the include/exclude patterns to regular files.
29    
30    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31        --exclude_dir in the tests to avoid scanning .svn directories.
32    
33    
34    Version 7.6 28-Jan-08
35    ---------------------
36    
37    1.  A character class containing a very large number of characters with
38        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
39        overflow.
40    
41    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
42        HAVE_LONG_LONG is not defined.
43    
44    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
45        bring them up to date and include new features. This patch includes:
46    
47        - Fixed PH's badly added libz and libbz2 support.
48        - Fixed a problem with static linking.
49        - Added pcredemo. [But later removed - see 7 below.]
50        - Fixed dftables problem and added an option.
51        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
52            HAVE_LONG_LONG.
53        - Added readline support for pcretest.
54        - Added an listing of the option settings after cmake has run.
55    
56    4.  A user submitted a patch to Makefile that makes it easy to create
57        "pcre.dll" under mingw when using Configure/Make. I added stuff to
58        Makefile.am that cause it to include this special target, without
59        affecting anything else. Note that the same mingw target plus all
60        the other distribution libraries and programs are now supported
61        when configuring with CMake (see 6 below) instead of with
62        Configure/Make.
63    
64    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
65        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
66        exported in the Windows port". It has not yet been confirmed that the patch
67        solves the problem, but it does no harm.
68    
69    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
70        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
71        with CMake, and also correct the comment about stack recursion.
72    
73    7.  Remove the automatic building of pcredemo from the ./configure system and
74        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
75        of a program that users should build themselves after PCRE is installed, so
76        building it automatically is not really right. What is more, it gave
77        trouble in some build environments.
78    
79    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
80    
81    
82    Version 7.5 10-Jan-08
83    ---------------------
84    
85    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
86        values in parens when parsing an RE using the C++ wrapper."
87    
88    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
89        Characters greater than 255 were excluded from the class instead of being
90        included.
91    
92    3.  The same bug as (2) above applied to negated POSIX classes such as
93        [:^space:].
94    
95    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
96        defined or documented. It seems to have been a typo for PCRE_STATIC, so
97        I have changed it.
98    
99    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
100        first named subpattern) and a construct such as (?&a) would reference the
101        first named subpattern whose name started with "a" (in other words, the
102        length check was missing). Both these problems are fixed. "Subpattern name
103        expected" is now given for (?&) (a zero-length name), and this patch also
104        makes it give the same error for \k'' (previously it complained that that
105        was a reference to a non-existent subpattern).
106    
107    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
108        this is right because (?- can be followed by option settings as well as by
109        digits. I have, however, made the messages clearer.
110    
111    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
112        than the number used in the conditional) now cause a compile-time error.
113        This is actually not compatible with Perl, which accepts such patterns, but
114        treats the conditional as always being FALSE (as PCRE used to), but it
115        seems to me that giving a diagnostic is better.
116    
117    8.  Change "alphameric" to the more common word "alphanumeric" in comments
118        and messages.
119    
120    9.  Fix two occurrences of "backslash" in comments that should have been
121        "backspace".
122    
123    10. Remove two redundant lines of code that can never be obeyed (their function
124        was moved elsewhere).
125    
126    11. The program that makes PCRE's Unicode character property table had a bug
127        which caused it to generate incorrect table entries for sequences of
128        characters that have the same character type, but are in different scripts.
129        It amalgamated them into a single range, with the script of the first of
130        them. In other words, some characters were in the wrong script. There were
131        thirteen such cases, affecting characters in the following ranges:
132    
133          U+002b0 - U+002c1
134          U+0060c - U+0060d
135          U+0061e - U+00612
136          U+0064b - U+0065e
137          U+0074d - U+0076d
138          U+01800 - U+01805
139          U+01d00 - U+01d77
140          U+01d9b - U+01dbf
141          U+0200b - U+0200f
142          U+030fc - U+030fe
143          U+03260 - U+0327f
144          U+0fb46 - U+0fbb1
145          U+10450 - U+1049d
146    
147    12. The -o option (show only the matching part of a line) for pcregrep was not
148        compatible with GNU grep in that, if there was more than one match in a
149        line, it showed only the first of them. It now behaves in the same way as
150        GNU grep.
151    
152    13. If the -o and -v options were combined for pcregrep, it printed a blank
153        line for every non-matching line. GNU grep prints nothing, and pcregrep now
154        does the same. The return code can be used to tell if there were any
155        non-matching lines.
156    
157    14. Added --file-offsets and --line-offsets to pcregrep.
158    
159    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
160        infinitely looping recursion. The bug was that positive lookaheads were not
161        being skipped when checking for a possible empty match (negative lookaheads
162        and both kinds of lookbehind were skipped).
163    
164    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
165        inclusion of <windows.h> to before rather than after the definition of
166        INVALID_FILE_ATTRIBUTES (patch from David Byron).
167    
168    17. Specifying a possessive quantifier with a specific limit for a Unicode
169        character property caused pcre_compile() to compile bad code, which led at
170        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
171        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
172        caused the error; without that there was no problem.
173    
174    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
175    
176    19. Added --enable-pcretest-libreadline.
177    
178    20. In pcrecpp.cc, the variable 'count' was incremented twice in
179        RE::GlobalReplace(). As a result, the number of replacements returned was
180        double what it should be. I removed one of the increments, but Craig sent a
181        later patch that removed the other one (the right fix) and added unit tests
182        that check the return values (which was not done before).
183    
184    21. Several CMake things:
185    
186        (1) Arranged that, when cmake is used on Unix, the libraries end up with
187            the names libpcre and libpcreposix, not just pcre and pcreposix.
188    
189        (2) The above change means that pcretest and pcregrep are now correctly
190            linked with the newly-built libraries, not previously installed ones.
191    
192        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
193    
194    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
195        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
196        UTF-8 newline character). The key issue is that the pattern starts .*;
197        this means that the match must be either at the beginning, or after a
198        newline. The bug was in the code for advancing after a failed match and
199        checking that the new position followed a newline. It was not taking
200        account of UTF-8 characters correctly.
201    
202    23. PCRE was behaving differently from Perl in the way it recognized POSIX
203        character classes. PCRE was not treating the sequence [:...:] as a
204        character class unless the ... were all letters. Perl, however, seems to
205        allow any characters between [: and :], though of course it rejects as
206        unknown any "names" that contain non-letters, because all the known class
207        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
208        for example, whereas PCRE did not - it did not recognize a POSIX character
209        class. This seemed a bit dangerous, so the code has been changed to be
210        closer to Perl. The behaviour is not identical to Perl, because PCRE will
211        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
212        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
213        Perl does, and where it didn't before.
214    
215    24. Rewrite so as to remove the single use of %n from pcregrep because in some
216        Windows environments %n is disabled by default.
217    
218    
219    Version 7.4 21-Sep-07
220    ---------------------
221    
222    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
223        means that a class such as [\s] counted as "explicit reference to CR or
224        LF". That isn't really right - the whole point of the change was to try to
225        help when there was an actual mention of one of the two characters. So now
226        the change happens only if \r or \n (or a literal CR or LF) character is
227        encountered.
228    
229    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
230        of both had grown to the point where there were only 3 bits left.
231        Fortunately, there was spare space in the data structure, and so I have
232        moved the internal flags into a new 16-bit field to free up more option
233        bits.
234    
235    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
236        but did not set the internal JCHANGED flag - either of these is enough to
237        control the way the "get" function works - but the PCRE_INFO_JCHANGED
238        facility is supposed to tell if (?J) was ever used, so now (?J) at the
239        start sets both bits.
240    
241    4.  Added options (at build time, compile time, exec time) to change \R from
242        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
243    
244    5.  doc/pcresyntax.html was missing from the distribution.
245    
246    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
247        compatibility, even though it is no longer used.
248    
249    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
250        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
251        windows.h file is present (where different names are used). [This was
252        reversed later after testing - see 16 below.]
253    
254    8.  Changed all #include <config.h> to #include "config.h". There were also
255        some further <pcre.h> cases that I changed to "pcre.h".
256    
257    9.  When pcregrep was used with the --colour option, it missed the line ending
258        sequence off the lines that it output.
259    
260    10. It was pointed out to me that arrays of string pointers cause lots of
261        relocations when a shared library is dynamically loaded. A technique of
262        using a single long string with a table of offsets can drastically reduce
263        these. I have refactored PCRE in four places to do this. The result is
264        dramatic:
265    
266          Originally:                          290
267          After changing UCP table:            187
268          After changing error message table:   43
269          After changing table of "verbs"       36
270          After changing table of Posix names   22
271    
272        Thanks to the folks working on Gregex for glib for this insight.
273    
274    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
275        unicode-properties was also set.
276    
277    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
278    
279    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
280        checked only for CRLF.
281    
282    14. Added casts to pcretest.c to avoid compiler warnings.
283    
284    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
285    
286    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
287        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
288        entirely. This removes changes made in 7 above.
289    
290    17. The CMake files have been updated, and there is now more information about
291        building with CMake in the NON-UNIX-USE document.
292    
293    
294    Version 7.3 28-Aug-07
295    ---------------------
296    
297     1. In the rejigging of the build system that eventually resulted in 7.1, the
298        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
299        brackets there is not right, since it causes compilers to look for an
300        installed pcre.h, not the version that is in the source that is being
301        compiled (which of course may be different). I have changed it back to:
302    
303          #include "pcre.h"
304    
305        I have a vague recollection that the change was concerned with compiling in
306        different directories, but in the new build system, that is taken care of
307        by the VPATH setting the Makefile.
308    
309     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
310        when the subject happened to end in the byte 0x85 (e.g. if the last
311        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
312        characters but of course it shouldn't be taken as a newline when it is part
313        of another character. The bug was that, for an unlimited repeat of . in
314        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
315        characters when looking for a newline.
316    
317     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
318    
319     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
320        in debug output.
321    
322     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
323        long printing in the pcrecpp unittest when running under MinGW.
324    
325     6. ESC_K was left out of the EBCDIC table.
326    
327     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
328        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
329        limit also applies to "virtual nesting" when a pattern is recursive, and in
330        this case 1000 isn't so big. I have been able to remove this limit at the
331        expense of backing off one optimization in certain circumstances. Normally,
332        when pcre_exec() would call its internal match() function recursively and
333        immediately return the result unconditionally, it uses a "tail recursion"
334        feature to save stack. However, when a subpattern that can match an empty
335        string has an unlimited repetition quantifier, it no longer makes this
336        optimization. That gives it a stack frame in which to save the data for
337        checking that an empty string has been matched. Previously this was taken
338        from the 1000-entry workspace that had been reserved. So now there is no
339        explicit limit, but more stack is used.
340    
341     8. Applied Daniel's patches to solve problems with the import/export magic
342        syntax that is required for Windows, and which was going wrong for the
343        pcreposix and pcrecpp parts of the library. These were overlooked when this
344        problem was solved for the main library.
345    
346     9. There were some crude static tests to avoid integer overflow when computing
347        the size of patterns that contain repeated groups with explicit upper
348        limits. As the maximum quantifier is 65535, the maximum group length was
349        set at 30,000 so that the product of these two numbers did not overflow a
350        32-bit integer. However, it turns out that people want to use groups that
351        are longer than 30,000 bytes (though not repeat them that many times).
352        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
353        made it possible to implement the integer overflow checks in a much more
354        dynamic way, which I have now done. The artificial limitation on group
355        length has been removed - we now have only the limit on the total length of
356        the compiled pattern, which depends on the LINK_SIZE setting.
357    
358    10. Fixed a bug in the documentation for get/copy named substring when
359        duplicate names are permitted. If none of the named substrings are set, the
360        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
361        empty string.
362    
363    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
364        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
365        because the ] is interpreted as the first data character and the
366        terminating ] is not found. PCRE has been made compatible with Perl in this
367        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
368        cause memory overwriting.
369    
370    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
371        string has been matched (to stop an infinite loop). It was not recognizing
372        a conditional subpattern that could match an empty string if that
373        subpattern was within another subpattern. For example, it looped when
374        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
375        condition was not nested. This bug has been fixed.
376    
377    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
378        past the start of the subject in the presence of bytes with the top bit
379        set, for example "\x8aBCD".
380    
381    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
382        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
383    
384    14. Optimized (?!) to (*FAIL).
385    
386    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
387        This restricts code points to be within the range 0 to 0x10FFFF, excluding
388        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
389        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
390        does: it's just the validity check that is more restrictive.
391    
392    16. Inserted checks for integer overflows during escape sequence (backslash)
393        processing, and also fixed erroneous offset values for syntax errors during
394        backslash processing.
395    
396    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
397        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
398    
399    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
400        caused an overrun.
401    
402    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
403        something other than just ASCII characters) inside a group that had an
404        unlimited repeat caused a loop at compile time (while checking to see
405        whether the group could match an empty string).
406    
407    20. Debugging a pattern containing \p or \P could cause a crash. For example,
408        [\P{Any}] did so. (Error in the code for printing property names.)
409    
410    21. An orphan \E inside a character class could cause a crash.
411    
412    22. A repeated capturing bracket such as (A)? could cause a wild memory
413        reference during compilation.
414    
415    23. There are several functions in pcre_compile() that scan along a compiled
416        expression for various reasons (e.g. to see if it's fixed length for look
417        behind). There were bugs in these functions when a repeated \p or \P was
418        present in the pattern. These operators have additional parameters compared
419        with \d, etc, and these were not being taken into account when moving along
420        the compiled data. Specifically:
421    
422        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
423            length.
424    
425        (b) An item such as \pL+ within a repeated group could cause crashes or
426            loops.
427    
428        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
429            "reference to non-existent subpattern" error.
430    
431        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
432    
433    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
434        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
435    
436    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
437    
438    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
439        character were causing crashes (broken optimization).
440    
441    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
442        \p or \P) caused a compile-time loop.
443    
444    28. More problems have arisen in unanchored patterns when CRLF is a valid line
445        break. For example, the unstudied pattern [\r\n]A does not match the string
446        "\r\nA" because change 7.0/46 below moves the current point on by two
447        characters after failing to match at the start. However, the pattern \nA
448        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
449        the same is true. There doesn't seem any very clean way out of this, but
450        what I have chosen to do makes the common cases work: PCRE now takes note
451        of whether there can be an explicit match for \r or \n anywhere in the
452        pattern, and if so, 7.0/46 no longer applies. As part of this change,
453        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
454        pattern has explicit CR or LF references.
455    
456    29. Added (*CR) etc for changing newline setting at start of pattern.
457    
458    
459    Version 7.2 19-Jun-07
460    ---------------------
461    
462     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
463        which is apparently normally available under Windows.
464    
465     2. Re-jig the pcregrep tests with different newline settings in an attempt
466        to make them independent of the local environment's newline setting.
467    
468     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
469    
470     4. Some of the "internals" tests were previously cut out when the link size
471        was not 2, because the output contained actual offsets. The recent new
472        "Z" feature of pcretest means that these can be cut out, making the tests
473        usable with all link sizes.
474    
475     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
476        stack recursion. This gives a massive performance boost under BSD, but just
477        a small improvement under Linux. However, it saves one field in the frame
478        in all cases.
479    
480     6. Added more features from the forthcoming Perl 5.10:
481    
482        (a) (?-n) (where n is a string of digits) is a relative subroutine or
483            recursion call. It refers to the nth most recently opened parentheses.
484    
485        (b) (?+n) is also a relative subroutine call; it refers to the nth next
486            to be opened parentheses.
487    
488        (c) Conditions that refer to capturing parentheses can be specified
489            relatively, for example, (?(-2)... or (?(+3)...
490    
491        (d) \K resets the start of the current match so that everything before
492            is not part of it.
493    
494        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
495    
496        (f) \g{name} is another synonym - part of Perl 5.10's unification of
497            reference syntax.
498    
499        (g) (?| introduces a group in which the numbering of parentheses in each
500            alternative starts with the same number.
501    
502        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
503    
504     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
505        PCRE_INFO_JCHANGED.
506    
507     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
508        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
509        for detecting groups that can match an empty string.
510    
511     9. A pattern with a very large number of alternatives (more than several
512        hundred) was running out of internal workspace during the pre-compile
513        phase, where pcre_compile() figures out how much memory will be needed. A
514        bit of new cunning has reduced the workspace needed for groups with
515        alternatives. The 1000-alternative test pattern now uses 12 bytes of
516        workspace instead of running out of the 4096 that are available.
517    
518    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
519    
520    11. Applied patch from Google to remove an optimization that didn't quite work.
521        The report of the bug said:
522    
523          pcrecpp::RE("a*").FullMatch("aaa") matches, while
524          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
525          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
526    
527    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
528        it matched the wrong number of bytes.
529    
530    
531    Version 7.1 24-Apr-07
532    ---------------------
533    
534     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
535        that is more "standard", making use of automake and other Autotools. There
536        is some re-arrangement of the files and adjustment of comments consequent
537        on this.
538    
539     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
540        for recursive directory scanning broke on some systems because the files
541        are not scanned in any specific order and on different systems the order
542        was different. A call to "sort" has been inserted into RunGrepTest for the
543        approprate test as a short-term fix. In the longer term there may be an
544        alternative.
545    
546     3. I had an email from Eric Raymond about problems translating some of PCRE's
547        man pages to HTML (despite the fact that I distribute HTML pages, some
548        people do their own conversions for various reasons). The problems
549        concerned the use of low-level troff macros .br and .in. I have therefore
550        removed all such uses from the man pages (some were redundant, some could
551        be replaced by .nf/.fi pairs). The 132html script that I use to generate
552        HTML has been updated to handle .nf/.fi and to complain if it encounters
553        .br or .in.
554    
555     4. Updated comments in configure.ac that get placed in config.h.in and also
556        arranged for config.h to be included in the distribution, with the name
557        config.h.generic, for the benefit of those who have to compile without
558        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
559    
560     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
561        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
562        makevp.bat for the current PCRE, using the additional files
563        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
564    
565     6. A Windows user reported a minor discrepancy with test 2, which turned out
566        to be caused by a trailing space on an input line that had got lost in his
567        copy. The trailing space was an accident, so I've just removed it.
568    
569     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
570        that is needed.
571    
572     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
573        as "const" (a) because they are and (b) because it helps the PHP
574        maintainers who have recently made a script to detect big data structures
575        in the php code that should be moved to the .rodata section. I remembered
576        to update Builducptable as well, so it won't revert if ucptable.h is ever
577        re-created.
578    
579     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
580        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
581        order to be able to cut out the UTF-8 tables in the latter when UTF-8
582        support is not required. This saves 1.5-2K of code, which is important in
583        some applications.
584    
585        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
586        so as not to refer to the tables, even though these functions will never be
587        called when UTF-8 support is disabled. Otherwise there are problems with a
588        shared library.
589    
590    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
591    
592        (a) It was defining its arguments as char * instead of void *.
593    
594        (b) It was assuming that all moves were upwards in memory; this was true
595            a long time ago when I wrote it, but is no longer the case.
596    
597        The emulated memove() is provided for those environments that have neither
598        memmove() nor bcopy(). I didn't think anyone used it these days, but that
599        is clearly not the case, as these two bugs were recently reported.
600    
601    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
602        and Detrail to create the HTML documentation, the .txt form of the man
603        pages, and it removes trailing spaces from listed files. It also creates
604        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
605        case, it wraps all the #defines with #ifndefs. This script should be run
606        before "make dist".
607    
608    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
609        with Unicode property support.
610    
611        (a) For a maximizing quantifier, if the two different cases of the
612            character were of different lengths in their UTF-8 codings (there are
613            some cases like this - I found 11), and the matching function had to
614            back up over a mixture of the two cases, it incorrectly assumed they
615            were both the same length.
616    
617        (b) When PCRE was configured to use the heap rather than the stack for
618            recursion during matching, it was not correctly preserving the data for
619            the other case of a UTF-8 character when checking ahead for a match
620            while processing a minimizing repeat. If the check also involved
621            matching a wide character, but failed, corruption could cause an
622            erroneous result when trying to check for a repeat of the original
623            character.
624    
625    13. Some tidying changes to the testing mechanism:
626    
627        (a) The RunTest script now detects the internal link size and whether there
628            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
629            values substituted by "configure". (The RunGrepTest script already did
630            this for UTF-8.) The configure.ac script no longer substitutes the
631            relevant variables.
632    
633        (b) The debugging options /B and /D in pcretest show the compiled bytecode
634            with length and offset values. This means that the output is different
635            for different internal link sizes. Test 2 is skipped for link sizes
636            other than 2 because of this, bypassing the problem. Unfortunately,
637            there was also a test in test 3 (the locale tests) that used /B and
638            failed for link sizes other than 2. Rather than cut the whole test out,
639            I have added a new /Z option to pcretest that replaces the length and
640            offset values with spaces. This is now used to make test 3 independent
641            of link size. (Test 2 will be tidied up later.)
642    
643    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
644        segmentation fault instead of returning the appropriate error message.
645    
646    15. In multiline mode when the newline sequence was set to "any", the pattern
647        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
648        This doesn't seem right; it now treats the CRLF combination as the line
649        ending, and so does not match in that case. It's only a pattern such as ^$
650        that would hit this one: something like ^ABC$ would have failed after \r
651        and then tried again after \r\n.
652    
653    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
654        in an attempt to make files that differ only in their line terminators
655        compare equal. This works on Linux.
656    
657    17. Under certain error circumstances pcregrep might try to free random memory
658        as it exited. This is now fixed, thanks to valgrind.
659    
660    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
661        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
662        was because its rules for how to advance for /g after matching an empty
663        string at the end of a line did not allow for this case. They now check for
664        it specially.
665    
666    20. pcretest is supposed to handle patterns and data of any length, by
667        extending its buffers when necessary. It was getting this wrong when the
668        buffer for a data line had to be extended.
669    
670    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
671        CRLF as a newline sequence.
672    
673    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
674        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
675        I have nevertheless tidied it up.
676    
677    23. Added some casts to kill warnings from HP-UX ia64 compiler.
678    
679    24. Added a man page for pcre-config.
680    
681    
682    Version 7.0 19-Dec-06
683    ---------------------
684    
685     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
686        moving to gcc 4.1.1.
687    
688     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
689        sys/time.h, which is documented as needed for this function. It doesn't
690        seem to matter on Linux, but it showed up on some releases of OS X.
691    
692     3. It seems that there are systems where bytes whose values are greater than
693        127 match isprint() in the "C" locale. The "C" locale should be the
694        default when a C program starts up. In most systems, only ASCII printing
695        characters match isprint(). This difference caused the output from pcretest
696        to vary, making some of the tests fail. I have changed pcretest so that:
697    
698        (a) When it is outputting text in the compiled version of a pattern, bytes
699            other than 32-126 are always shown as hex escapes.
700    
701        (b) When it is outputting text that is a matched part of a subject string,
702            it does the same, unless a different locale has been set for the match
703            (using the /L modifier). In this case, it uses isprint() to decide.
704    
705     4. Fixed a major bug that caused incorrect computation of the amount of memory
706        required for a compiled pattern when options that changed within the
707        pattern affected the logic of the preliminary scan that determines the
708        length. The relevant options are -x, and -i in UTF-8 mode. The result was
709        that the computed length was too small. The symptoms of this bug were
710        either the PCRE error "internal error: code overflow" from pcre_compile(),
711        or a glibc crash with a message such as "pcretest: free(): invalid next
712        size (fast)". Examples of patterns that provoked this bug (shown in
713        pcretest format) are:
714    
715          /(?-x: )/x
716          /(?x)(?-x: \s*#\s*)/
717          /((?i)[\x{c0}])/8
718          /(?i:[\x{c0}])/8
719    
720        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
721        is now done differently.
722    
723     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
724        wrapper classes; (b) implement a new function in the C++ scanner that is
725        more efficient than the old way of doing things because it avoids levels of
726        recursion in the regex matching; (c) add a paragraph to the documentation
727        for the FullMatch() function.
728    
729     6. The escape sequence \n was being treated as whatever was defined as
730        "newline". Not only was this contrary to the documentation, which states
731        that \n is character 10 (hex 0A), but it also went horribly wrong when
732        "newline" was defined as CRLF. This has been fixed.
733    
734     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
735        was being set to -1 for the "end of line" case (supposedly a value that no
736        character can have). Though this value is never used (the check for end of
737        line is "zero bytes in current character"), it caused compiler complaints.
738        I've changed it to 0xffffffff.
739    
740     8. In pcre_version.c, the version string was being built by a sequence of
741        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
742        string (as it is for production releases) called a macro with an empty
743        argument. The C standard says the result of this is undefined. The gcc
744        compiler treats it as an empty string (which was what was wanted) but it is
745        reported that Visual C gives an error. The source has been hacked around to
746        avoid this problem.
747    
748     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
749        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
750        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
751        of them did).
752    
753    10. Originally, pcretest opened its input and output without "b"; then I was
754        told that "b" was needed in some environments, so it was added for release
755        5.0 to both the input and output. (It makes no difference on Unix-like
756        systems.) Later I was told that it is wrong for the input on Windows. I've
757        now abstracted the modes into two macros, to make it easier to fiddle with
758        them, and removed "b" from the input mode under Windows.
759    
760    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
761    
762    12. Added -help and --help to pcretest as an official way of being reminded
763        of the options.
764    
765    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
766        and pcrecpp.cc because they annoy compilers at high warning levels.
767    
768    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
769    
770    15. Fixed an occurrence of == in configure.ac that should have been = (shell
771        scripts are not C programs :-) and which was not noticed because it works
772        on Linux.
773    
774    16. pcretest is supposed to handle any length of pattern and data line (as one
775        line or as a continued sequence of lines) by extending its input buffer if
776        necessary. This feature was broken for very long pattern lines, leading to
777        a string of junk being passed to pcre_compile() if the pattern was longer
778        than about 50K.
779    
780    17. I have done a major re-factoring of the way pcre_compile() computes the
781        amount of memory needed for a compiled pattern. Previously, there was code
782        that made a preliminary scan of the pattern in order to do this. That was
783        OK when PCRE was new, but as the facilities have expanded, it has become
784        harder and harder to keep it in step with the real compile phase, and there
785        have been a number of bugs (see for example, 4 above). I have now found a
786        cunning way of running the real compile function in a "fake" mode that
787        enables it to compute how much memory it would need, while actually only
788        ever using a few hundred bytes of working memory and without too many
789        tests of the mode. This should make future maintenance and development
790        easier. A side effect of this work is that the limit of 200 on the nesting
791        depth of parentheses has been removed (though this was never a serious
792        limitation, I suspect). However, there is a downside: pcre_compile() now
793        runs more slowly than before (30% or more, depending on the pattern). I
794        hope this isn't a big issue. There is no effect on runtime performance.
795    
796    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
797        newline (only possible for the last line of a file) and it was a
798        pattern that set a locale (followed by /Lsomething), pcretest crashed.
799    
800    19. Added additional timing features to pcretest. (1) The -tm option now times
801        matching only, not compiling. (2) Both -t and -tm can be followed, as a
802        separate command line item, by a number that specifies the number of
803        repeats to use when timing. The default is 50000; this gives better
804        precision, but takes uncomfortably long for very large patterns.
805    
806    20. Extended pcre_study() to be more clever in cases where a branch of a
807        subpattern has no definite first character. For example, (a*|b*)[cd] would
808        previously give no result from pcre_study(). Now it recognizes that the
809        first character must be a, b, c, or d.
810    
811    21. There was an incorrect error "recursive call could loop indefinitely" if
812        a subpattern (or the entire pattern) that was being tested for matching an
813        empty string contained only one non-empty item after a nested subpattern.
814        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
815        incorrectly, because the \d was being skipped in the check.
816    
817    22. The pcretest program now has a new pattern option /B and a command line
818        option -b, which is equivalent to adding /B to every pattern. This causes
819        it to show the compiled bytecode, without the additional information that
820        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
821        is the same as /B/I).
822    
823    23. A new optimization is now able automatically to treat some sequences such
824        as a*b as a*+b. More specifically, if something simple (such as a character
825        or a simple class like \d) has an unlimited quantifier, and is followed by
826        something that cannot possibly match the quantified thing, the quantifier
827        is automatically "possessified".
828    
829    24. A recursive reference to a subpattern whose number was greater than 39
830        went wrong under certain circumstances in UTF-8 mode. This bug could also
831        have affected the operation of pcre_study().
832    
833    25. Realized that a little bit of performance could be had by replacing
834        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
835    
836    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
837    
838    27. Possessive quantifiers such as a++ were previously implemented by turning
839        them into atomic groups such as ($>a+). Now they have their own opcodes,
840        which improves performance. This includes the automatically created ones
841        from 23 above.
842    
843    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
844        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
845        the first matched character to be a colon. This applied both to named and
846        numbered groups.
847    
848    29. The ucpinternal.h header file was missing its idempotency #ifdef.
849    
850    30. I was sent a "project" file called libpcre.a.dev which I understand makes
851        building PCRE on Windows easier, so I have included it in the distribution.
852    
853    31. There is now a check in pcretest against a ridiculously large number being
854        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
855        loop, the loop is abandoned.
856    
857    32. Forward references to subpatterns in conditions such as (?(2)...) where
858        subpattern 2 is defined later cause pcre_compile() to search forwards in
859        the pattern for the relevant set of parentheses. This search went wrong
860        when there were unescaped parentheses in a character class, parentheses
861        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
862    
863    33. "Subroutine" calls and backreferences were previously restricted to
864        referencing subpatterns earlier in the regex. This restriction has now
865        been removed.
866    
867    34. Added a number of extra features that are going to be in Perl 5.10. On the
868        whole, these are just syntactic alternatives for features that PCRE had
869        previously implemented using the Python syntax or my own invention. The
870        other formats are all retained for compatibility.
871    
872        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
873            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
874            also .NET compatible.
875    
876        (b) A recursion or subroutine call to a named group can now be defined as
877            (?&name) as well as (?P>name).
878    
879        (c) A backreference to a named group can now be defined as \k<name> or
880            \k'name' as well as (?P=name). The new forms, as well as being in Perl
881            5.10, are also .NET compatible.
882    
883        (d) A conditional reference to a named group can now use the syntax
884            (?(<name>) or (?('name') as well as (?(name).
885    
886        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
887            groups (named and numbered) that are never evaluated inline, but can be
888            called as "subroutines" from elsewhere. In effect, the DEFINE condition
889            is always false. There may be only one alternative in such a group.
890    
891        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
892            as the simple (?(R). The condition is true only if the most recent
893            recursion is that of the given number or name. It does not search out
894            through the entire recursion stack.
895    
896        (g) The escape \gN or \g{N} has been added, where N is a positive or
897            negative number, specifying an absolute or relative reference.
898    
899    35. Tidied to get rid of some further signed/unsigned compiler warnings and
900        some "unreachable code" warnings.
901    
902    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
903        things, this adds five new scripts.
904    
905    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
906        There were also incompatibilities regarding the handling of \Q..\E inside
907        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
908        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
909    
910    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
911        matches an empty string, and forcibly breaks the loop. There were bugs in
912        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
913        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
914        separate and independent bugs (that affected different cases) have been
915        fixed.
916    
917    39. Refactored the code to abolish the use of different opcodes for small
918        capturing bracket numbers. This is a tidy that I avoided doing when I
919        removed the limit on the number of capturing brackets for 3.5 back in 2001.
920        The new approach is not only tidier, it makes it possible to reduce the
921        memory needed to fix the previous bug (38).
922    
923    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
924        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
925        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
926        mode.
927    
928    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
929        report.
930    
931    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
932        copy construction and assignment in the C++ wrapper.
933    
934    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
935        couple of bugs that could have given wrong results in the "--newline=crlf"
936        case.
937    
938    44. Added a number of casts and did some reorganization of signed/unsigned int
939        variables following suggestions from Dair Grant. Also renamed the variable
940        "this" as "item" because it is a C++ keyword.
941    
942    45. Arranged for dftables to add
943    
944          #include "pcre_internal.h"
945    
946        to pcre_chartables.c because without it, gcc 4.x may remove the array
947        definition from the final binary if PCRE is built into a static library and
948        dead code stripping is activated.
949    
950    46. For an unanchored pattern, if a match attempt fails at the start of a
951        newline sequence, and the newline setting is CRLF or ANY, and the next two
952        characters are CRLF, advance by two characters instead of one.
953    
954    
955    Version 6.7 04-Jul-06
956    ---------------------
957    
958     1. In order to handle tests when input lines are enormously long, pcretest has
959        been re-factored so that it automatically extends its buffers when
960        necessary. The code is crude, but this _is_ just a test program. The
961        default size has been increased from 32K to 50K.
962    
963     2. The code in pcre_study() was using the value of the re argument before
964        testing it for NULL. (Of course, in any sensible call of the function, it
965        won't be NULL.)
966    
967     3. The memmove() emulation function in pcre_internal.h, which is used on
968        systems that lack both memmove() and bcopy() - that is, hardly ever -
969        was missing a "static" storage class specifier.
970    
971     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
972        containing an extended class (one that cannot be represented by a bitmap
973        because it contains high-valued characters or Unicode property items, e.g.
974        [\pZ]). Almost always one would set UTF-8 mode when processing such a
975        pattern, but PCRE should not loop if you do not (it no longer does).
976        [Detail: two cases were found: (a) a repeated subpattern containing an
977        extended class; (b) a recursive reference to a subpattern that followed a
978        previous extended class. It wasn't skipping over the extended class
979        correctly when UTF-8 mode was not set.]
980    
981     5. A negated single-character class was not being recognized as fixed-length
982        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
983        compile error "lookbehind assertion is not fixed length".
984    
985     6. The RunPerlTest auxiliary script was showing an unexpected difference
986        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
987        write a Perl script that can interpret lines of an input file either as
988        byte characters or as UTF-8, which is what "perltest" was being required to
989        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
990        can't do is switch easily at run time between having the "use utf8;" pragma
991        or not. In the end, I fudged it by using the RunPerlTest script to insert
992        "use utf8;" explicitly for the UTF-8 tests.
993    
994     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
995        the end of the subject string, contrary to the documentation and to what
996        Perl does. This was true of both matching functions. Now it matches only at
997        the start of the subject and immediately after *internal* newlines.
998    
999     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1000        a pointer to an int instead of a pointer to an unsigned long int. This
1001        caused problems on 64-bit systems.
1002    
1003     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1004        instance of the 'standard' template library not being so standard".
1005    
1006    10. There was no check on the number of named subpatterns nor the maximum
1007        length of a subpattern name. The product of these values is used to compute
1008        the size of the memory block for a compiled pattern. By supplying a very
1009        long subpattern name and a large number of named subpatterns, the size
1010        computation could be caused to overflow. This is now prevented by limiting
1011        the length of names to 32 characters, and the number of named subpatterns
1012        to 10,000.
1013    
1014    11. Subpatterns that are repeated with specific counts have to be replicated in
1015        the compiled pattern. The size of memory for this was computed from the
1016        length of the subpattern and the repeat count. The latter is limited to
1017        65535, but there was no limit on the former, meaning that integer overflow
1018        could in principle occur. The compiled length of a repeated subpattern is
1019        now limited to 30,000 bytes in order to prevent this.
1020    
1021    12. Added the optional facility to have named substrings with the same name.
1022    
1023    13. Added the ability to use a named substring as a condition, using the
1024        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1025        are numbers (not recommended). Forward references are permitted.
1026    
1027    14. Added forward references in named backreferences (if you see what I mean).
1028    
1029    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1030        pattern could run off the end of the subject. For example, the pattern
1031        "(?s)(.{1,5})"8 did this with the subject "ab".
1032    
1033    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1034        PCRE_CASELESS was set when matching characters that were quantified with ?
1035        or *.
1036    
1037    17. A character class other than a single negated character that had a minimum
1038        but no maximum quantifier - for example [ab]{6,} - was not handled
1039        correctly by pce_dfa_exec(). It would match only one character.
1040    
1041    18. A valid (though odd) pattern that looked like a POSIX character
1042        class but used an invalid character after [ (for example [[,abc,]]) caused
1043        pcre_compile() to give the error "Failed: internal error: code overflow" or
1044        in some cases to crash with a glibc free() error. This could even happen if
1045        the pattern terminated after [[ but there just happened to be a sequence of
1046        letters, a binary zero, and a closing ] in the memory that followed.
1047    
1048    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1049        over the years. Originally (before any Unicode support), just the bottom 8
1050        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1051        output from "man perlunicode" includes this:
1052    
1053          The regular expression compiler produces polymorphic opcodes.  That
1054          is, the pattern adapts to the data and automatically switches to
1055          the Unicode character scheme when presented with Unicode data--or
1056          instead uses a traditional byte scheme when presented with byte
1057          data.
1058    
1059        Sadly, a wide octal escape does not cause a switch, and in a string with
1060        no other multibyte characters, these octal escapes are treated as before.
1061        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1062        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1063        Unicode string.
1064    
1065        I have not perpetrated such confusion in PCRE. Up till now, it took just
1066        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1067        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1068        translate to the appropriate multibyte character.
1069    
1070    29. Applied some refactoring to reduce the number of warnings from Microsoft
1071        and Borland compilers. This has included removing the fudge introduced
1072        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1073        a warning about an unused variable.
1074    
1075    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1076        characters since release 4.0, because Perl (from release 5.004) does not.
1077        [Or at least, is documented not to: some releases seem to be in conflict
1078        with the documentation.] However, when a pattern was studied with
1079        pcre_study() and all its branches started with \s, PCRE still included VT
1080        as a possible starting character. Of course, this did no harm; it just
1081        caused an unnecessary match attempt.
1082    
1083    22. Removed a now-redundant internal flag bit that recorded the fact that case
1084        dependency changed within the pattern. This was once needed for "required
1085        byte" processing, but is no longer used. This recovers a now-scarce options
1086        bit. Also moved the least significant internal flag bit to the most-
1087        significant bit of the word, which was not previously used (hangover from
1088        the days when it was an int rather than a uint) to free up another bit for
1089        the future.
1090    
1091    23. Added support for CRLF line endings as well as CR and LF. As well as the
1092        default being selectable at build time, it can now be changed at runtime
1093        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1094        specify that it is scanning data with non-default line endings.
1095    
1096    24. Changed the definition of CXXLINK to make it agree with the definition of
1097        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1098    
1099    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1100        recursions. This makes a big different to stack usage for some patterns.
1101    
1102    26. If a subpattern containing a named recursion or subroutine reference such
1103        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1104        the space required for the compiled pattern went wrong and gave too small a
1105        value. Depending on the environment, this could lead to "Failed: internal
1106        error: code overflow at offset 49" or "glibc detected double free or
1107        corruption" errors.
1108    
1109    27. Applied patches from Google (a) to support the new newline modes and (b) to
1110        advance over multibyte UTF-8 characters in GlobalReplace.
1111    
1112    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1113        difference for some implementation of PCRE in some Windows version.
1114    
1115    29. Added some extra testing facilities to pcretest:
1116    
1117        \q<number>   in a data line sets the "match limit" value
1118        \Q<number>   in a data line sets the "match recursion limt" value
1119        -S <number>  sets the stack size, where <number> is in megabytes
1120    
1121        The -S option isn't available for Windows.
1122    
1123    
1124    Version 6.6 06-Feb-06
1125    ---------------------
1126    
1127     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1128        in pcreposix.h. I have copied the definition from pcre.h.
1129    
1130     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1131        because pcre.h is no longer a built file.
1132    
1133     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1134        not normally included in the compiled code.
1135    
1136    
1137    Version 6.5 01-Feb-06
1138    ---------------------
1139    
1140     1. When using the partial match feature with pcre_dfa_exec(), it was not
1141        anchoring the second and subsequent partial matches at the new starting
1142        point. This could lead to incorrect results. For example, with the pattern
1143        /1234/, partially matching against "123" and then "a4" gave a match.
1144    
1145     2. Changes to pcregrep:
1146    
1147        (a) All non-match returns from pcre_exec() were being treated as failures
1148            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1149            error message is output. Some extra information is given for the
1150            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1151            probably the only errors that are likely to be caused by users (by
1152            specifying a regex that has nested indefinite repeats, for instance).
1153            If there are more than 20 of these errors, pcregrep is abandoned.
1154    
1155        (b) A binary zero was treated as data while matching, but terminated the
1156            output line if it was written out. This has been fixed: binary zeroes
1157            are now no different to any other data bytes.
1158    
1159        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1160            used to set a locale for matching. The --locale=xxxx long option has
1161            been added (no short equivalent) to specify a locale explicitly on the
1162            pcregrep command, overriding the environment variables.
1163    
1164        (d) When -B was used with -n, some line numbers in the output were one less
1165            than they should have been.
1166    
1167        (e) Added the -o (--only-matching) option.
1168    
1169        (f) If -A or -C was used with -c (count only), some lines of context were
1170            accidentally printed for the final match.
1171    
1172        (g) Added the -H (--with-filename) option.
1173    
1174        (h) The combination of options -rh failed to suppress file names for files
1175            that were found from directory arguments.
1176    
1177        (i) Added the -D (--devices) and -d (--directories) options.
1178    
1179        (j) Added the -F (--fixed-strings) option.
1180    
1181        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1182    
1183        (l) Added the --colo(u)r option.
1184    
1185        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1186            is not present by default.
1187    
1188     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1189        items such as (?R) or (?1), when the recursion could match a number of
1190        alternatives. If it matched one of the alternatives, but subsequently,
1191        outside the recursion, there was a failure, the code tried to back up into
1192        the recursion. However, because of the way PCRE is implemented, this is not
1193        possible, and the result was an incorrect result from the match.
1194    
1195        In order to prevent this happening, the specification of recursion has
1196        been changed so that all such subpatterns are automatically treated as
1197        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1198    
1199     4. I had overlooked the fact that, in some locales, there are characters for
1200        which isalpha() is true but neither isupper() nor islower() are true. In
1201        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1202        and ordfeminine) are like this. This affected the treatment of \w and \W
1203        when they appeared in character classes, but not when they appeared outside
1204        a character class. The bit map for "word" characters is now created
1205        separately from the results of isalnum() instead of just taking it from the
1206        upper, lower, and digit maps. (Plus the underscore character, of course.)
1207    
1208     5. The above bug also affected the handling of POSIX character classes such as
1209        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1210        permanent tables. Instead, the bit maps for such a class were previously
1211        created as the appropriate unions of the upper, lower, and digit bitmaps.
1212        Now they are created by subtraction from the [[:word:]] class, which has
1213        its own bitmap.
1214    
1215     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1216        It is created by subtracting the vertical space characters (\x09, \x0a,
1217        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1218        subtraction was done in the overall bitmap for a character class, meaning
1219        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1220        be recognized. This bug has been fixed.
1221    
1222     7. Patches from the folks at Google:
1223    
1224          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1225          real life, but is still worth protecting against".
1226    
1227          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1228          regular expressions".
1229    
1230          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1231          have it.
1232    
1233          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1234          "configure" and the latter not, in order to fix a problem somebody had
1235          with compiling the Arg class on HP-UX.
1236    
1237          (e) Improve the error-handling of the C++ wrapper a little bit.
1238    
1239          (f) New tests for checking recursion limiting.
1240    
1241     8. The pcre_memmove() function, which is used only if the environment does not
1242        have a standard memmove() function (and is therefore rarely compiled),
1243        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1244        returning a result (though PCRE never actually uses the result).
1245    
1246     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1247        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1248        returned instead of calling malloc() with an overflowing number that would
1249        most likely cause subsequent chaos.
1250    
1251    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1252    
1253    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1254        with this option is matched, the nmatch and pmatch options of regexec() are
1255        ignored.
1256    
1257    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1258        provided in case anyone wants to the the POSIX interface with UTF-8
1259        strings.
1260    
1261    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1262        C++ linking (needed for some HP-UX environments).
1263    
1264    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1265        (unused parameter) and in the pcre_printint() function (omitted "default"
1266        switch label when the default is to do nothing).
1267    
1268    15. Added some code to make it possible, when PCRE is compiled as a C++
1269        library, to replace subject pointers for pcre_exec() with a smart pointer
1270        class, thus making it possible to process discontinuous strings.
1271    
1272    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1273        much the same function. They were added by different people who were trying
1274        to make PCRE easy to compile on non-Unix systems. It has been suggested
1275        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1276        for compiling on Windows systems. I have therefore replaced it with
1277        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1278        defaults to "extern" for C or "extern C" for C++, which works fine on
1279        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1280        SCOPE with something explicit in config.h. In addition:
1281    
1282        (a) pcreposix.h still had just "extern" instead of either of these macros;
1283            I have replaced it with PCRE_DATA_SCOPE.
1284    
1285        (b) Functions such as _pcre_xclass(), which are internal to the library,
1286            but external in the C sense, all had PCRE_EXPORT in their definitions.
1287            This is apparently wrong for the Windows case, so I have removed it.
1288            (It makes no difference on Unix-like systems.)
1289    
1290    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1291        of recursive calls to match(). This is different to MATCH_LIMIT because
1292        that limits the total number of calls to match(), not all of which increase
1293        the depth of recursion. Limiting the recursion depth limits the amount of
1294        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1295        when PCRE is compiled, and changed at run time. A patch from Google adds
1296        this functionality to the C++ interface.
1297    
1298    18. Changes to the handling of Unicode character properties:
1299    
1300        (a) Updated the table to Unicode 4.1.0.
1301    
1302        (b) Recognize characters that are not in the table as "Cn" (undefined).
1303    
1304        (c) I revised the way the table is implemented to a much improved format
1305            which includes recognition of ranges. It now supports the ranges that
1306            are defined in UnicodeData.txt, and it also amalgamates other
1307            characters into ranges. This has reduced the number of entries in the
1308            table from around 16,000 to around 3,000, thus reducing its size
1309            considerably. I realized I did not need to use a tree structure after
1310            all - a binary chop search is just as efficient. Having reduced the
1311            number of entries, I extended their size from 6 bytes to 8 bytes to
1312            allow for more data.
1313    
1314        (d) Added support for Unicode script names via properties such as \p{Han}.
1315    
1316    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1317        matching that character.
1318    
1319    20. When matching a repeated Unicode property with a minimum greater than zero,
1320        (for example \pL{2,}), PCRE could look past the end of the subject if it
1321        reached it while seeking the minimum number of characters. This could
1322        happen only if some of the characters were more than one byte long, because
1323        there is a check for at least the minimum number of bytes.
1324    
1325    21. Refactored the implementation of \p and \P so as to be more general, to
1326        allow for more different types of property in future. This has changed the
1327        compiled form incompatibly. Anybody with saved compiled patterns that use
1328        \p or \P will have to recompile them.
1329    
1330    22. Added "Any" and "L&" to the supported property types.
1331    
1332    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1333        but give a compile time error if the value is greater than 0xff.
1334    
1335    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1336        accidentally not being installed or uninstalled.
1337    
1338    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1339        made were to insert the current release number. This seemed silly, because
1340        it made things harder for people building PCRE on systems that don't run
1341        "configure". I have turned pcre.h into a distributed file, no longer built
1342        by "configure", with the version identification directly included. There is
1343        no longer a pcre.h.in file.
1344    
1345        However, this change necessitated a change to the pcre-config script as
1346        well. It is built from pcre-config.in, and one of the substitutions was the
1347        release number. I have updated configure.ac so that ./configure now finds
1348        the release number by grepping pcre.h.
1349    
1350    26. Added the ability to run the tests under valgrind.
1351    
1352    
1353    Version 6.4 05-Sep-05
1354    ---------------------
1355    
1356     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1357        "--" to be printed when multiple files were scanned, even when none of the
1358        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1359        consider it to be a bug, and have restored the previous behaviour.
1360    
1361     2. A couple of code tidies to get rid of compiler warnings.
1362    
1363     3. The pcretest program used to cheat by referring to symbols in the library
1364        whose names begin with _pcre_. These are internal symbols that are not
1365        really supposed to be visible externally, and in some environments it is
1366        possible to suppress them. The cheating is now confined to including
1367        certain files from the library's source, which is a bit cleaner.
1368    
1369     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1370        file's purpose clearer.
1371    
1372     5. Reorganized pcre_ucp_findchar().
1373    
1374    
1375    Version 6.3 15-Aug-05
1376    ---------------------
1377    
1378     1. The file libpcre.pc.in did not have general read permission in the tarball.
1379    
1380     2. There were some problems when building without C++ support:
1381    
1382        (a) If C++ support was not built, "make install" and "make test" still
1383            tried to test it.
1384    
1385        (b) There were problems when the value of CXX was explicitly set. Some
1386            changes have been made to try to fix these, and ...
1387    
1388        (c) --disable-cpp can now be used to explicitly disable C++ support.
1389    
1390        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1391            backslash in a target when C++ was disabled. This confuses some
1392            versions of "make", apparently. Using an intermediate variable solves
1393            this. (Same for CPP_LOBJ.)
1394    
1395     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1396        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1397        necessary on certain architectures.
1398    
1399     4. Added a setting of -export-symbols-regex to the link command to remove
1400        those symbols that are exported in the C sense, but actually are local
1401        within the library, and not documented. Their names all begin with
1402        "_pcre_". This is not a perfect job, because (a) we have to except some
1403        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1404        available (and never for static libraries). I have made a note to try to
1405        find a way round (a) in the future.
1406    
1407    
1408  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
1409  ---------------------  ---------------------
1410    

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