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

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