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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 333 by ph10, Thu Apr 10 19:55:57 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. (See also #8 below.)
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. (Subsequently also a second patch to fix the
42        first patch. And a third patch - this was a messy problem.)
43    
44    9.  Applied Craig's patch to remove the use of push_back().
45    
46    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
47        matching function regexec().
48    
49    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
50        which, however, unlike Perl's \g{...}, are subroutine calls, not back
51        references. PCRE supports relative numbers with this syntax (I don't think
52        Oniguruma does).
53    
54    
55    Version 7.6 28-Jan-08
56    ---------------------
57    
58    1.  A character class containing a very large number of characters with
59        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
60        overflow.
61    
62    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
63        HAVE_LONG_LONG is not defined.
64    
65    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
66        bring them up to date and include new features. This patch includes:
67    
68        - Fixed PH's badly added libz and libbz2 support.
69        - Fixed a problem with static linking.
70        - Added pcredemo. [But later removed - see 7 below.]
71        - Fixed dftables problem and added an option.
72        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
73            HAVE_LONG_LONG.
74        - Added readline support for pcretest.
75        - Added an listing of the option settings after cmake has run.
76    
77    4.  A user submitted a patch to Makefile that makes it easy to create
78        "pcre.dll" under mingw when using Configure/Make. I added stuff to
79        Makefile.am that cause it to include this special target, without
80        affecting anything else. Note that the same mingw target plus all
81        the other distribution libraries and programs are now supported
82        when configuring with CMake (see 6 below) instead of with
83        Configure/Make.
84    
85    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
86        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
87        exported in the Windows port". It has not yet been confirmed that the patch
88        solves the problem, but it does no harm.
89    
90    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
91        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
92        with CMake, and also correct the comment about stack recursion.
93    
94    7.  Remove the automatic building of pcredemo from the ./configure system and
95        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
96        of a program that users should build themselves after PCRE is installed, so
97        building it automatically is not really right. What is more, it gave
98        trouble in some build environments.
99    
100    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
101    
102    
103    Version 7.5 10-Jan-08
104    ---------------------
105    
106    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
107        values in parens when parsing an RE using the C++ wrapper."
108    
109    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
110        Characters greater than 255 were excluded from the class instead of being
111        included.
112    
113    3.  The same bug as (2) above applied to negated POSIX classes such as
114        [:^space:].
115    
116    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
117        defined or documented. It seems to have been a typo for PCRE_STATIC, so
118        I have changed it.
119    
120    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
121        first named subpattern) and a construct such as (?&a) would reference the
122        first named subpattern whose name started with "a" (in other words, the
123        length check was missing). Both these problems are fixed. "Subpattern name
124        expected" is now given for (?&) (a zero-length name), and this patch also
125        makes it give the same error for \k'' (previously it complained that that
126        was a reference to a non-existent subpattern).
127    
128    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
129        this is right because (?- can be followed by option settings as well as by
130        digits. I have, however, made the messages clearer.
131    
132    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
133        than the number used in the conditional) now cause a compile-time error.
134        This is actually not compatible with Perl, which accepts such patterns, but
135        treats the conditional as always being FALSE (as PCRE used to), but it
136        seems to me that giving a diagnostic is better.
137    
138    8.  Change "alphameric" to the more common word "alphanumeric" in comments
139        and messages.
140    
141    9.  Fix two occurrences of "backslash" in comments that should have been
142        "backspace".
143    
144    10. Remove two redundant lines of code that can never be obeyed (their function
145        was moved elsewhere).
146    
147    11. The program that makes PCRE's Unicode character property table had a bug
148        which caused it to generate incorrect table entries for sequences of
149        characters that have the same character type, but are in different scripts.
150        It amalgamated them into a single range, with the script of the first of
151        them. In other words, some characters were in the wrong script. There were
152        thirteen such cases, affecting characters in the following ranges:
153    
154          U+002b0 - U+002c1
155          U+0060c - U+0060d
156          U+0061e - U+00612
157          U+0064b - U+0065e
158          U+0074d - U+0076d
159          U+01800 - U+01805
160          U+01d00 - U+01d77
161          U+01d9b - U+01dbf
162          U+0200b - U+0200f
163          U+030fc - U+030fe
164          U+03260 - U+0327f
165          U+0fb46 - U+0fbb1
166          U+10450 - U+1049d
167    
168    12. The -o option (show only the matching part of a line) for pcregrep was not
169        compatible with GNU grep in that, if there was more than one match in a
170        line, it showed only the first of them. It now behaves in the same way as
171        GNU grep.
172    
173    13. If the -o and -v options were combined for pcregrep, it printed a blank
174        line for every non-matching line. GNU grep prints nothing, and pcregrep now
175        does the same. The return code can be used to tell if there were any
176        non-matching lines.
177    
178    14. Added --file-offsets and --line-offsets to pcregrep.
179    
180    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
181        infinitely looping recursion. The bug was that positive lookaheads were not
182        being skipped when checking for a possible empty match (negative lookaheads
183        and both kinds of lookbehind were skipped).
184    
185    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
186        inclusion of <windows.h> to before rather than after the definition of
187        INVALID_FILE_ATTRIBUTES (patch from David Byron).
188    
189    17. Specifying a possessive quantifier with a specific limit for a Unicode
190        character property caused pcre_compile() to compile bad code, which led at
191        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
192        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
193        caused the error; without that there was no problem.
194    
195    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
196    
197    19. Added --enable-pcretest-libreadline.
198    
199    20. In pcrecpp.cc, the variable 'count' was incremented twice in
200        RE::GlobalReplace(). As a result, the number of replacements returned was
201        double what it should be. I removed one of the increments, but Craig sent a
202        later patch that removed the other one (the right fix) and added unit tests
203        that check the return values (which was not done before).
204    
205    21. Several CMake things:
206    
207        (1) Arranged that, when cmake is used on Unix, the libraries end up with
208            the names libpcre and libpcreposix, not just pcre and pcreposix.
209    
210        (2) The above change means that pcretest and pcregrep are now correctly
211            linked with the newly-built libraries, not previously installed ones.
212    
213        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
214    
215    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
216        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
217        UTF-8 newline character). The key issue is that the pattern starts .*;
218        this means that the match must be either at the beginning, or after a
219        newline. The bug was in the code for advancing after a failed match and
220        checking that the new position followed a newline. It was not taking
221        account of UTF-8 characters correctly.
222    
223    23. PCRE was behaving differently from Perl in the way it recognized POSIX
224        character classes. PCRE was not treating the sequence [:...:] as a
225        character class unless the ... were all letters. Perl, however, seems to
226        allow any characters between [: and :], though of course it rejects as
227        unknown any "names" that contain non-letters, because all the known class
228        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
229        for example, whereas PCRE did not - it did not recognize a POSIX character
230        class. This seemed a bit dangerous, so the code has been changed to be
231        closer to Perl. The behaviour is not identical to Perl, because PCRE will
232        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
233        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
234        Perl does, and where it didn't before.
235    
236    24. Rewrite so as to remove the single use of %n from pcregrep because in some
237        Windows environments %n is disabled by default.
238    
239    
240    Version 7.4 21-Sep-07
241    ---------------------
242    
243    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
244        means that a class such as [\s] counted as "explicit reference to CR or
245        LF". That isn't really right - the whole point of the change was to try to
246        help when there was an actual mention of one of the two characters. So now
247        the change happens only if \r or \n (or a literal CR or LF) character is
248        encountered.
249    
250    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
251        of both had grown to the point where there were only 3 bits left.
252        Fortunately, there was spare space in the data structure, and so I have
253        moved the internal flags into a new 16-bit field to free up more option
254        bits.
255    
256    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
257        but did not set the internal JCHANGED flag - either of these is enough to
258        control the way the "get" function works - but the PCRE_INFO_JCHANGED
259        facility is supposed to tell if (?J) was ever used, so now (?J) at the
260        start sets both bits.
261    
262    4.  Added options (at build time, compile time, exec time) to change \R from
263        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
264    
265    5.  doc/pcresyntax.html was missing from the distribution.
266    
267    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
268        compatibility, even though it is no longer used.
269    
270    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
271        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
272        windows.h file is present (where different names are used). [This was
273        reversed later after testing - see 16 below.]
274    
275    8.  Changed all #include <config.h> to #include "config.h". There were also
276        some further <pcre.h> cases that I changed to "pcre.h".
277    
278    9.  When pcregrep was used with the --colour option, it missed the line ending
279        sequence off the lines that it output.
280    
281    10. It was pointed out to me that arrays of string pointers cause lots of
282        relocations when a shared library is dynamically loaded. A technique of
283        using a single long string with a table of offsets can drastically reduce
284        these. I have refactored PCRE in four places to do this. The result is
285        dramatic:
286    
287          Originally:                          290
288          After changing UCP table:            187
289          After changing error message table:   43
290          After changing table of "verbs"       36
291          After changing table of Posix names   22
292    
293        Thanks to the folks working on Gregex for glib for this insight.
294    
295    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
296        unicode-properties was also set.
297    
298    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
299    
300    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
301        checked only for CRLF.
302    
303    14. Added casts to pcretest.c to avoid compiler warnings.
304    
305    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
306    
307    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
308        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
309        entirely. This removes changes made in 7 above.
310    
311    17. The CMake files have been updated, and there is now more information about
312        building with CMake in the NON-UNIX-USE document.
313    
314    
315    Version 7.3 28-Aug-07
316    ---------------------
317    
318     1. In the rejigging of the build system that eventually resulted in 7.1, the
319        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
320        brackets there is not right, since it causes compilers to look for an
321        installed pcre.h, not the version that is in the source that is being
322        compiled (which of course may be different). I have changed it back to:
323    
324          #include "pcre.h"
325    
326        I have a vague recollection that the change was concerned with compiling in
327        different directories, but in the new build system, that is taken care of
328        by the VPATH setting the Makefile.
329    
330     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
331        when the subject happened to end in the byte 0x85 (e.g. if the last
332        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
333        characters but of course it shouldn't be taken as a newline when it is part
334        of another character. The bug was that, for an unlimited repeat of . in
335        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
336        characters when looking for a newline.
337    
338     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
339    
340     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
341        in debug output.
342    
343     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
344        long printing in the pcrecpp unittest when running under MinGW.
345    
346     6. ESC_K was left out of the EBCDIC table.
347    
348     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
349        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
350        limit also applies to "virtual nesting" when a pattern is recursive, and in
351        this case 1000 isn't so big. I have been able to remove this limit at the
352        expense of backing off one optimization in certain circumstances. Normally,
353        when pcre_exec() would call its internal match() function recursively and
354        immediately return the result unconditionally, it uses a "tail recursion"
355        feature to save stack. However, when a subpattern that can match an empty
356        string has an unlimited repetition quantifier, it no longer makes this
357        optimization. That gives it a stack frame in which to save the data for
358        checking that an empty string has been matched. Previously this was taken
359        from the 1000-entry workspace that had been reserved. So now there is no
360        explicit limit, but more stack is used.
361    
362     8. Applied Daniel's patches to solve problems with the import/export magic
363        syntax that is required for Windows, and which was going wrong for the
364        pcreposix and pcrecpp parts of the library. These were overlooked when this
365        problem was solved for the main library.
366    
367     9. There were some crude static tests to avoid integer overflow when computing
368        the size of patterns that contain repeated groups with explicit upper
369        limits. As the maximum quantifier is 65535, the maximum group length was
370        set at 30,000 so that the product of these two numbers did not overflow a
371        32-bit integer. However, it turns out that people want to use groups that
372        are longer than 30,000 bytes (though not repeat them that many times).
373        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
374        made it possible to implement the integer overflow checks in a much more
375        dynamic way, which I have now done. The artificial limitation on group
376        length has been removed - we now have only the limit on the total length of
377        the compiled pattern, which depends on the LINK_SIZE setting.
378    
379    10. Fixed a bug in the documentation for get/copy named substring when
380        duplicate names are permitted. If none of the named substrings are set, the
381        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
382        empty string.
383    
384    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
385        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
386        because the ] is interpreted as the first data character and the
387        terminating ] is not found. PCRE has been made compatible with Perl in this
388        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
389        cause memory overwriting.
390    
391    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
392        string has been matched (to stop an infinite loop). It was not recognizing
393        a conditional subpattern that could match an empty string if that
394        subpattern was within another subpattern. For example, it looped when
395        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
396        condition was not nested. This bug has been fixed.
397    
398    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
399        past the start of the subject in the presence of bytes with the top bit
400        set, for example "\x8aBCD".
401    
402    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
403        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
404    
405    14. Optimized (?!) to (*FAIL).
406    
407    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
408        This restricts code points to be within the range 0 to 0x10FFFF, excluding
409        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
410        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
411        does: it's just the validity check that is more restrictive.
412    
413    16. Inserted checks for integer overflows during escape sequence (backslash)
414        processing, and also fixed erroneous offset values for syntax errors during
415        backslash processing.
416    
417    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
418        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
419    
420    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
421        caused an overrun.
422    
423    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
424        something other than just ASCII characters) inside a group that had an
425        unlimited repeat caused a loop at compile time (while checking to see
426        whether the group could match an empty string).
427    
428    20. Debugging a pattern containing \p or \P could cause a crash. For example,
429        [\P{Any}] did so. (Error in the code for printing property names.)
430    
431    21. An orphan \E inside a character class could cause a crash.
432    
433    22. A repeated capturing bracket such as (A)? could cause a wild memory
434        reference during compilation.
435    
436    23. There are several functions in pcre_compile() that scan along a compiled
437        expression for various reasons (e.g. to see if it's fixed length for look
438        behind). There were bugs in these functions when a repeated \p or \P was
439        present in the pattern. These operators have additional parameters compared
440        with \d, etc, and these were not being taken into account when moving along
441        the compiled data. Specifically:
442    
443        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
444            length.
445    
446        (b) An item such as \pL+ within a repeated group could cause crashes or
447            loops.
448    
449        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
450            "reference to non-existent subpattern" error.
451    
452        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
453    
454    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
455        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
456    
457    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
458    
459    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
460        character were causing crashes (broken optimization).
461    
462    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
463        \p or \P) caused a compile-time loop.
464    
465    28. More problems have arisen in unanchored patterns when CRLF is a valid line
466        break. For example, the unstudied pattern [\r\n]A does not match the string
467        "\r\nA" because change 7.0/46 below moves the current point on by two
468        characters after failing to match at the start. However, the pattern \nA
469        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
470        the same is true. There doesn't seem any very clean way out of this, but
471        what I have chosen to do makes the common cases work: PCRE now takes note
472        of whether there can be an explicit match for \r or \n anywhere in the
473        pattern, and if so, 7.0/46 no longer applies. As part of this change,
474        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
475        pattern has explicit CR or LF references.
476    
477    29. Added (*CR) etc for changing newline setting at start of pattern.
478    
479    
480    Version 7.2 19-Jun-07
481    ---------------------
482    
483     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
484        which is apparently normally available under Windows.
485    
486     2. Re-jig the pcregrep tests with different newline settings in an attempt
487        to make them independent of the local environment's newline setting.
488    
489     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
490    
491     4. Some of the "internals" tests were previously cut out when the link size
492        was not 2, because the output contained actual offsets. The recent new
493        "Z" feature of pcretest means that these can be cut out, making the tests
494        usable with all link sizes.
495    
496     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
497        stack recursion. This gives a massive performance boost under BSD, but just
498        a small improvement under Linux. However, it saves one field in the frame
499        in all cases.
500    
501     6. Added more features from the forthcoming Perl 5.10:
502    
503        (a) (?-n) (where n is a string of digits) is a relative subroutine or
504            recursion call. It refers to the nth most recently opened parentheses.
505    
506        (b) (?+n) is also a relative subroutine call; it refers to the nth next
507            to be opened parentheses.
508    
509        (c) Conditions that refer to capturing parentheses can be specified
510            relatively, for example, (?(-2)... or (?(+3)...
511    
512        (d) \K resets the start of the current match so that everything before
513            is not part of it.
514    
515        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
516    
517        (f) \g{name} is another synonym - part of Perl 5.10's unification of
518            reference syntax.
519    
520        (g) (?| introduces a group in which the numbering of parentheses in each
521            alternative starts with the same number.
522    
523        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
524    
525     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
526        PCRE_INFO_JCHANGED.
527    
528     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
529        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
530        for detecting groups that can match an empty string.
531    
532     9. A pattern with a very large number of alternatives (more than several
533        hundred) was running out of internal workspace during the pre-compile
534        phase, where pcre_compile() figures out how much memory will be needed. A
535        bit of new cunning has reduced the workspace needed for groups with
536        alternatives. The 1000-alternative test pattern now uses 12 bytes of
537        workspace instead of running out of the 4096 that are available.
538    
539    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
540    
541    11. Applied patch from Google to remove an optimization that didn't quite work.
542        The report of the bug said:
543    
544          pcrecpp::RE("a*").FullMatch("aaa") matches, while
545          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
546          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
547    
548    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
549        it matched the wrong number of bytes.
550    
551    
552    Version 7.1 24-Apr-07
553    ---------------------
554    
555     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
556        that is more "standard", making use of automake and other Autotools. There
557        is some re-arrangement of the files and adjustment of comments consequent
558        on this.
559    
560     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
561        for recursive directory scanning broke on some systems because the files
562        are not scanned in any specific order and on different systems the order
563        was different. A call to "sort" has been inserted into RunGrepTest for the
564        approprate test as a short-term fix. In the longer term there may be an
565        alternative.
566    
567     3. I had an email from Eric Raymond about problems translating some of PCRE's
568        man pages to HTML (despite the fact that I distribute HTML pages, some
569        people do their own conversions for various reasons). The problems
570        concerned the use of low-level troff macros .br and .in. I have therefore
571        removed all such uses from the man pages (some were redundant, some could
572        be replaced by .nf/.fi pairs). The 132html script that I use to generate
573        HTML has been updated to handle .nf/.fi and to complain if it encounters
574        .br or .in.
575    
576     4. Updated comments in configure.ac that get placed in config.h.in and also
577        arranged for config.h to be included in the distribution, with the name
578        config.h.generic, for the benefit of those who have to compile without
579        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
580    
581     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
582        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
583        makevp.bat for the current PCRE, using the additional files
584        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
585    
586     6. A Windows user reported a minor discrepancy with test 2, which turned out
587        to be caused by a trailing space on an input line that had got lost in his
588        copy. The trailing space was an accident, so I've just removed it.
589    
590     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
591        that is needed.
592    
593     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
594        as "const" (a) because they are and (b) because it helps the PHP
595        maintainers who have recently made a script to detect big data structures
596        in the php code that should be moved to the .rodata section. I remembered
597        to update Builducptable as well, so it won't revert if ucptable.h is ever
598        re-created.
599    
600     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
601        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
602        order to be able to cut out the UTF-8 tables in the latter when UTF-8
603        support is not required. This saves 1.5-2K of code, which is important in
604        some applications.
605    
606        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
607        so as not to refer to the tables, even though these functions will never be
608        called when UTF-8 support is disabled. Otherwise there are problems with a
609        shared library.
610    
611    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
612    
613        (a) It was defining its arguments as char * instead of void *.
614    
615        (b) It was assuming that all moves were upwards in memory; this was true
616            a long time ago when I wrote it, but is no longer the case.
617    
618        The emulated memove() is provided for those environments that have neither
619        memmove() nor bcopy(). I didn't think anyone used it these days, but that
620        is clearly not the case, as these two bugs were recently reported.
621    
622    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
623        and Detrail to create the HTML documentation, the .txt form of the man
624        pages, and it removes trailing spaces from listed files. It also creates
625        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
626        case, it wraps all the #defines with #ifndefs. This script should be run
627        before "make dist".
628    
629    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
630        with Unicode property support.
631    
632        (a) For a maximizing quantifier, if the two different cases of the
633            character were of different lengths in their UTF-8 codings (there are
634            some cases like this - I found 11), and the matching function had to
635            back up over a mixture of the two cases, it incorrectly assumed they
636            were both the same length.
637    
638        (b) When PCRE was configured to use the heap rather than the stack for
639            recursion during matching, it was not correctly preserving the data for
640            the other case of a UTF-8 character when checking ahead for a match
641            while processing a minimizing repeat. If the check also involved
642            matching a wide character, but failed, corruption could cause an
643            erroneous result when trying to check for a repeat of the original
644            character.
645    
646    13. Some tidying changes to the testing mechanism:
647    
648        (a) The RunTest script now detects the internal link size and whether there
649            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
650            values substituted by "configure". (The RunGrepTest script already did
651            this for UTF-8.) The configure.ac script no longer substitutes the
652            relevant variables.
653    
654        (b) The debugging options /B and /D in pcretest show the compiled bytecode
655            with length and offset values. This means that the output is different
656            for different internal link sizes. Test 2 is skipped for link sizes
657            other than 2 because of this, bypassing the problem. Unfortunately,
658            there was also a test in test 3 (the locale tests) that used /B and
659            failed for link sizes other than 2. Rather than cut the whole test out,
660            I have added a new /Z option to pcretest that replaces the length and
661            offset values with spaces. This is now used to make test 3 independent
662            of link size. (Test 2 will be tidied up later.)
663    
664    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
665        segmentation fault instead of returning the appropriate error message.
666    
667    15. In multiline mode when the newline sequence was set to "any", the pattern
668        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
669        This doesn't seem right; it now treats the CRLF combination as the line
670        ending, and so does not match in that case. It's only a pattern such as ^$
671        that would hit this one: something like ^ABC$ would have failed after \r
672        and then tried again after \r\n.
673    
674    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
675        in an attempt to make files that differ only in their line terminators
676        compare equal. This works on Linux.
677    
678    17. Under certain error circumstances pcregrep might try to free random memory
679        as it exited. This is now fixed, thanks to valgrind.
680    
681    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
682        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
683        was because its rules for how to advance for /g after matching an empty
684        string at the end of a line did not allow for this case. They now check for
685        it specially.
686    
687    20. pcretest is supposed to handle patterns and data of any length, by
688        extending its buffers when necessary. It was getting this wrong when the
689        buffer for a data line had to be extended.
690    
691    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
692        CRLF as a newline sequence.
693    
694    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
695        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
696        I have nevertheless tidied it up.
697    
698    23. Added some casts to kill warnings from HP-UX ia64 compiler.
699    
700    24. Added a man page for pcre-config.
701    
702    
703    Version 7.0 19-Dec-06
704    ---------------------
705    
706     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
707        moving to gcc 4.1.1.
708    
709     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
710        sys/time.h, which is documented as needed for this function. It doesn't
711        seem to matter on Linux, but it showed up on some releases of OS X.
712    
713     3. It seems that there are systems where bytes whose values are greater than
714        127 match isprint() in the "C" locale. The "C" locale should be the
715        default when a C program starts up. In most systems, only ASCII printing
716        characters match isprint(). This difference caused the output from pcretest
717        to vary, making some of the tests fail. I have changed pcretest so that:
718    
719        (a) When it is outputting text in the compiled version of a pattern, bytes
720            other than 32-126 are always shown as hex escapes.
721    
722        (b) When it is outputting text that is a matched part of a subject string,
723            it does the same, unless a different locale has been set for the match
724            (using the /L modifier). In this case, it uses isprint() to decide.
725    
726     4. Fixed a major bug that caused incorrect computation of the amount of memory
727        required for a compiled pattern when options that changed within the
728        pattern affected the logic of the preliminary scan that determines the
729        length. The relevant options are -x, and -i in UTF-8 mode. The result was
730        that the computed length was too small. The symptoms of this bug were
731        either the PCRE error "internal error: code overflow" from pcre_compile(),
732        or a glibc crash with a message such as "pcretest: free(): invalid next
733        size (fast)". Examples of patterns that provoked this bug (shown in
734        pcretest format) are:
735    
736          /(?-x: )/x
737          /(?x)(?-x: \s*#\s*)/
738          /((?i)[\x{c0}])/8
739          /(?i:[\x{c0}])/8
740    
741        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
742        is now done differently.
743    
744     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
745        wrapper classes; (b) implement a new function in the C++ scanner that is
746        more efficient than the old way of doing things because it avoids levels of
747        recursion in the regex matching; (c) add a paragraph to the documentation
748        for the FullMatch() function.
749    
750     6. The escape sequence \n was being treated as whatever was defined as
751        "newline". Not only was this contrary to the documentation, which states
752        that \n is character 10 (hex 0A), but it also went horribly wrong when
753        "newline" was defined as CRLF. This has been fixed.
754    
755     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
756        was being set to -1 for the "end of line" case (supposedly a value that no
757        character can have). Though this value is never used (the check for end of
758        line is "zero bytes in current character"), it caused compiler complaints.
759        I've changed it to 0xffffffff.
760    
761     8. In pcre_version.c, the version string was being built by a sequence of
762        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
763        string (as it is for production releases) called a macro with an empty
764        argument. The C standard says the result of this is undefined. The gcc
765        compiler treats it as an empty string (which was what was wanted) but it is
766        reported that Visual C gives an error. The source has been hacked around to
767        avoid this problem.
768    
769     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
770        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
771        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
772        of them did).
773    
774    10. Originally, pcretest opened its input and output without "b"; then I was
775        told that "b" was needed in some environments, so it was added for release
776        5.0 to both the input and output. (It makes no difference on Unix-like
777        systems.) Later I was told that it is wrong for the input on Windows. I've
778        now abstracted the modes into two macros, to make it easier to fiddle with
779        them, and removed "b" from the input mode under Windows.
780    
781    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
782    
783    12. Added -help and --help to pcretest as an official way of being reminded
784        of the options.
785    
786    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
787        and pcrecpp.cc because they annoy compilers at high warning levels.
788    
789    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
790    
791    15. Fixed an occurrence of == in configure.ac that should have been = (shell
792        scripts are not C programs :-) and which was not noticed because it works
793        on Linux.
794    
795    16. pcretest is supposed to handle any length of pattern and data line (as one
796        line or as a continued sequence of lines) by extending its input buffer if
797        necessary. This feature was broken for very long pattern lines, leading to
798        a string of junk being passed to pcre_compile() if the pattern was longer
799        than about 50K.
800    
801    17. I have done a major re-factoring of the way pcre_compile() computes the
802        amount of memory needed for a compiled pattern. Previously, there was code
803        that made a preliminary scan of the pattern in order to do this. That was
804        OK when PCRE was new, but as the facilities have expanded, it has become
805        harder and harder to keep it in step with the real compile phase, and there
806        have been a number of bugs (see for example, 4 above). I have now found a
807        cunning way of running the real compile function in a "fake" mode that
808        enables it to compute how much memory it would need, while actually only
809        ever using a few hundred bytes of working memory and without too many
810        tests of the mode. This should make future maintenance and development
811        easier. A side effect of this work is that the limit of 200 on the nesting
812        depth of parentheses has been removed (though this was never a serious
813        limitation, I suspect). However, there is a downside: pcre_compile() now
814        runs more slowly than before (30% or more, depending on the pattern). I
815        hope this isn't a big issue. There is no effect on runtime performance.
816    
817    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
818        newline (only possible for the last line of a file) and it was a
819        pattern that set a locale (followed by /Lsomething), pcretest crashed.
820    
821    19. Added additional timing features to pcretest. (1) The -tm option now times
822        matching only, not compiling. (2) Both -t and -tm can be followed, as a
823        separate command line item, by a number that specifies the number of
824        repeats to use when timing. The default is 50000; this gives better
825        precision, but takes uncomfortably long for very large patterns.
826    
827    20. Extended pcre_study() to be more clever in cases where a branch of a
828        subpattern has no definite first character. For example, (a*|b*)[cd] would
829        previously give no result from pcre_study(). Now it recognizes that the
830        first character must be a, b, c, or d.
831    
832    21. There was an incorrect error "recursive call could loop indefinitely" if
833        a subpattern (or the entire pattern) that was being tested for matching an
834        empty string contained only one non-empty item after a nested subpattern.
835        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
836        incorrectly, because the \d was being skipped in the check.
837    
838    22. The pcretest program now has a new pattern option /B and a command line
839        option -b, which is equivalent to adding /B to every pattern. This causes
840        it to show the compiled bytecode, without the additional information that
841        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
842        is the same as /B/I).
843    
844    23. A new optimization is now able automatically to treat some sequences such
845        as a*b as a*+b. More specifically, if something simple (such as a character
846        or a simple class like \d) has an unlimited quantifier, and is followed by
847        something that cannot possibly match the quantified thing, the quantifier
848        is automatically "possessified".
849    
850    24. A recursive reference to a subpattern whose number was greater than 39
851        went wrong under certain circumstances in UTF-8 mode. This bug could also
852        have affected the operation of pcre_study().
853    
854    25. Realized that a little bit of performance could be had by replacing
855        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
856    
857    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
858    
859    27. Possessive quantifiers such as a++ were previously implemented by turning
860        them into atomic groups such as ($>a+). Now they have their own opcodes,
861        which improves performance. This includes the automatically created ones
862        from 23 above.
863    
864    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
865        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
866        the first matched character to be a colon. This applied both to named and
867        numbered groups.
868    
869    29. The ucpinternal.h header file was missing its idempotency #ifdef.
870    
871    30. I was sent a "project" file called libpcre.a.dev which I understand makes
872        building PCRE on Windows easier, so I have included it in the distribution.
873    
874    31. There is now a check in pcretest against a ridiculously large number being
875        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
876        loop, the loop is abandoned.
877    
878    32. Forward references to subpatterns in conditions such as (?(2)...) where
879        subpattern 2 is defined later cause pcre_compile() to search forwards in
880        the pattern for the relevant set of parentheses. This search went wrong
881        when there were unescaped parentheses in a character class, parentheses
882        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
883    
884    33. "Subroutine" calls and backreferences were previously restricted to
885        referencing subpatterns earlier in the regex. This restriction has now
886        been removed.
887    
888    34. Added a number of extra features that are going to be in Perl 5.10. On the
889        whole, these are just syntactic alternatives for features that PCRE had
890        previously implemented using the Python syntax or my own invention. The
891        other formats are all retained for compatibility.
892    
893        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
894            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
895            also .NET compatible.
896    
897        (b) A recursion or subroutine call to a named group can now be defined as
898            (?&name) as well as (?P>name).
899    
900        (c) A backreference to a named group can now be defined as \k<name> or
901            \k'name' as well as (?P=name). The new forms, as well as being in Perl
902            5.10, are also .NET compatible.
903    
904        (d) A conditional reference to a named group can now use the syntax
905            (?(<name>) or (?('name') as well as (?(name).
906    
907        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
908            groups (named and numbered) that are never evaluated inline, but can be
909            called as "subroutines" from elsewhere. In effect, the DEFINE condition
910            is always false. There may be only one alternative in such a group.
911    
912        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
913            as the simple (?(R). The condition is true only if the most recent
914            recursion is that of the given number or name. It does not search out
915            through the entire recursion stack.
916    
917        (g) The escape \gN or \g{N} has been added, where N is a positive or
918            negative number, specifying an absolute or relative reference.
919    
920    35. Tidied to get rid of some further signed/unsigned compiler warnings and
921        some "unreachable code" warnings.
922    
923    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
924        things, this adds five new scripts.
925    
926    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
927        There were also incompatibilities regarding the handling of \Q..\E inside
928        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
929        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
930    
931    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
932        matches an empty string, and forcibly breaks the loop. There were bugs in
933        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
934        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
935        separate and independent bugs (that affected different cases) have been
936        fixed.
937    
938    39. Refactored the code to abolish the use of different opcodes for small
939        capturing bracket numbers. This is a tidy that I avoided doing when I
940        removed the limit on the number of capturing brackets for 3.5 back in 2001.
941        The new approach is not only tidier, it makes it possible to reduce the
942        memory needed to fix the previous bug (38).
943    
944    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
945        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
946        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
947        mode.
948    
949    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
950        report.
951    
952    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
953        copy construction and assignment in the C++ wrapper.
954    
955    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
956        couple of bugs that could have given wrong results in the "--newline=crlf"
957        case.
958    
959    44. Added a number of casts and did some reorganization of signed/unsigned int
960        variables following suggestions from Dair Grant. Also renamed the variable
961        "this" as "item" because it is a C++ keyword.
962    
963    45. Arranged for dftables to add
964    
965          #include "pcre_internal.h"
966    
967        to pcre_chartables.c because without it, gcc 4.x may remove the array
968        definition from the final binary if PCRE is built into a static library and
969        dead code stripping is activated.
970    
971    46. For an unanchored pattern, if a match attempt fails at the start of a
972        newline sequence, and the newline setting is CRLF or ANY, and the next two
973        characters are CRLF, advance by two characters instead of one.
974    
975    
976    Version 6.7 04-Jul-06
977    ---------------------
978    
979     1. In order to handle tests when input lines are enormously long, pcretest has
980        been re-factored so that it automatically extends its buffers when
981        necessary. The code is crude, but this _is_ just a test program. The
982        default size has been increased from 32K to 50K.
983    
984     2. The code in pcre_study() was using the value of the re argument before
985        testing it for NULL. (Of course, in any sensible call of the function, it
986        won't be NULL.)
987    
988     3. The memmove() emulation function in pcre_internal.h, which is used on
989        systems that lack both memmove() and bcopy() - that is, hardly ever -
990        was missing a "static" storage class specifier.
991    
992     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
993        containing an extended class (one that cannot be represented by a bitmap
994        because it contains high-valued characters or Unicode property items, e.g.
995        [\pZ]). Almost always one would set UTF-8 mode when processing such a
996        pattern, but PCRE should not loop if you do not (it no longer does).
997        [Detail: two cases were found: (a) a repeated subpattern containing an
998        extended class; (b) a recursive reference to a subpattern that followed a
999        previous extended class. It wasn't skipping over the extended class
1000        correctly when UTF-8 mode was not set.]
1001    
1002     5. A negated single-character class was not being recognized as fixed-length
1003        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1004        compile error "lookbehind assertion is not fixed length".
1005    
1006     6. The RunPerlTest auxiliary script was showing an unexpected difference
1007        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1008        write a Perl script that can interpret lines of an input file either as
1009        byte characters or as UTF-8, which is what "perltest" was being required to
1010        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1011        can't do is switch easily at run time between having the "use utf8;" pragma
1012        or not. In the end, I fudged it by using the RunPerlTest script to insert
1013        "use utf8;" explicitly for the UTF-8 tests.
1014    
1015     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1016        the end of the subject string, contrary to the documentation and to what
1017        Perl does. This was true of both matching functions. Now it matches only at
1018        the start of the subject and immediately after *internal* newlines.
1019    
1020     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1021        a pointer to an int instead of a pointer to an unsigned long int. This
1022        caused problems on 64-bit systems.
1023    
1024     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1025        instance of the 'standard' template library not being so standard".
1026    
1027    10. There was no check on the number of named subpatterns nor the maximum
1028        length of a subpattern name. The product of these values is used to compute
1029        the size of the memory block for a compiled pattern. By supplying a very
1030        long subpattern name and a large number of named subpatterns, the size
1031        computation could be caused to overflow. This is now prevented by limiting
1032        the length of names to 32 characters, and the number of named subpatterns
1033        to 10,000.
1034    
1035    11. Subpatterns that are repeated with specific counts have to be replicated in
1036        the compiled pattern. The size of memory for this was computed from the
1037        length of the subpattern and the repeat count. The latter is limited to
1038        65535, but there was no limit on the former, meaning that integer overflow
1039        could in principle occur. The compiled length of a repeated subpattern is
1040        now limited to 30,000 bytes in order to prevent this.
1041    
1042    12. Added the optional facility to have named substrings with the same name.
1043    
1044    13. Added the ability to use a named substring as a condition, using the
1045        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1046        are numbers (not recommended). Forward references are permitted.
1047    
1048    14. Added forward references in named backreferences (if you see what I mean).
1049    
1050    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1051        pattern could run off the end of the subject. For example, the pattern
1052        "(?s)(.{1,5})"8 did this with the subject "ab".
1053    
1054    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1055        PCRE_CASELESS was set when matching characters that were quantified with ?
1056        or *.
1057    
1058    17. A character class other than a single negated character that had a minimum
1059        but no maximum quantifier - for example [ab]{6,} - was not handled
1060        correctly by pce_dfa_exec(). It would match only one character.
1061    
1062    18. A valid (though odd) pattern that looked like a POSIX character
1063        class but used an invalid character after [ (for example [[,abc,]]) caused
1064        pcre_compile() to give the error "Failed: internal error: code overflow" or
1065        in some cases to crash with a glibc free() error. This could even happen if
1066        the pattern terminated after [[ but there just happened to be a sequence of
1067        letters, a binary zero, and a closing ] in the memory that followed.
1068    
1069    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1070        over the years. Originally (before any Unicode support), just the bottom 8
1071        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1072        output from "man perlunicode" includes this:
1073    
1074          The regular expression compiler produces polymorphic opcodes.  That
1075          is, the pattern adapts to the data and automatically switches to
1076          the Unicode character scheme when presented with Unicode data--or
1077          instead uses a traditional byte scheme when presented with byte
1078          data.
1079    
1080        Sadly, a wide octal escape does not cause a switch, and in a string with
1081        no other multibyte characters, these octal escapes are treated as before.
1082        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1083        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1084        Unicode string.
1085    
1086        I have not perpetrated such confusion in PCRE. Up till now, it took just
1087        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1088        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1089        translate to the appropriate multibyte character.
1090    
1091    29. Applied some refactoring to reduce the number of warnings from Microsoft
1092        and Borland compilers. This has included removing the fudge introduced
1093        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1094        a warning about an unused variable.
1095    
1096    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1097        characters since release 4.0, because Perl (from release 5.004) does not.
1098        [Or at least, is documented not to: some releases seem to be in conflict
1099        with the documentation.] However, when a pattern was studied with
1100        pcre_study() and all its branches started with \s, PCRE still included VT
1101        as a possible starting character. Of course, this did no harm; it just
1102        caused an unnecessary match attempt.
1103    
1104    22. Removed a now-redundant internal flag bit that recorded the fact that case
1105        dependency changed within the pattern. This was once needed for "required
1106        byte" processing, but is no longer used. This recovers a now-scarce options
1107        bit. Also moved the least significant internal flag bit to the most-
1108        significant bit of the word, which was not previously used (hangover from
1109        the days when it was an int rather than a uint) to free up another bit for
1110        the future.
1111    
1112    23. Added support for CRLF line endings as well as CR and LF. As well as the
1113        default being selectable at build time, it can now be changed at runtime
1114        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1115        specify that it is scanning data with non-default line endings.
1116    
1117    24. Changed the definition of CXXLINK to make it agree with the definition of
1118        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1119    
1120    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1121        recursions. This makes a big different to stack usage for some patterns.
1122    
1123    26. If a subpattern containing a named recursion or subroutine reference such
1124        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1125        the space required for the compiled pattern went wrong and gave too small a
1126        value. Depending on the environment, this could lead to "Failed: internal
1127        error: code overflow at offset 49" or "glibc detected double free or
1128        corruption" errors.
1129    
1130    27. Applied patches from Google (a) to support the new newline modes and (b) to
1131        advance over multibyte UTF-8 characters in GlobalReplace.
1132    
1133    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1134        difference for some implementation of PCRE in some Windows version.
1135    
1136    29. Added some extra testing facilities to pcretest:
1137    
1138        \q<number>   in a data line sets the "match limit" value
1139        \Q<number>   in a data line sets the "match recursion limt" value
1140        -S <number>  sets the stack size, where <number> is in megabytes
1141    
1142        The -S option isn't available for Windows.
1143    
1144    
1145    Version 6.6 06-Feb-06
1146    ---------------------
1147    
1148     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1149        in pcreposix.h. I have copied the definition from pcre.h.
1150    
1151     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1152        because pcre.h is no longer a built file.
1153    
1154     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1155        not normally included in the compiled code.
1156    
1157    
1158    Version 6.5 01-Feb-06
1159    ---------------------
1160    
1161     1. When using the partial match feature with pcre_dfa_exec(), it was not
1162        anchoring the second and subsequent partial matches at the new starting
1163        point. This could lead to incorrect results. For example, with the pattern
1164        /1234/, partially matching against "123" and then "a4" gave a match.
1165    
1166     2. Changes to pcregrep:
1167    
1168        (a) All non-match returns from pcre_exec() were being treated as failures
1169            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1170            error message is output. Some extra information is given for the
1171            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1172            probably the only errors that are likely to be caused by users (by
1173            specifying a regex that has nested indefinite repeats, for instance).
1174            If there are more than 20 of these errors, pcregrep is abandoned.
1175    
1176        (b) A binary zero was treated as data while matching, but terminated the
1177            output line if it was written out. This has been fixed: binary zeroes
1178            are now no different to any other data bytes.
1179    
1180        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1181            used to set a locale for matching. The --locale=xxxx long option has
1182            been added (no short equivalent) to specify a locale explicitly on the
1183            pcregrep command, overriding the environment variables.
1184    
1185        (d) When -B was used with -n, some line numbers in the output were one less
1186            than they should have been.
1187    
1188        (e) Added the -o (--only-matching) option.
1189    
1190        (f) If -A or -C was used with -c (count only), some lines of context were
1191            accidentally printed for the final match.
1192    
1193        (g) Added the -H (--with-filename) option.
1194    
1195        (h) The combination of options -rh failed to suppress file names for files
1196            that were found from directory arguments.
1197    
1198        (i) Added the -D (--devices) and -d (--directories) options.
1199    
1200        (j) Added the -F (--fixed-strings) option.
1201    
1202        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1203    
1204        (l) Added the --colo(u)r option.
1205    
1206        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1207            is not present by default.
1208    
1209     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1210        items such as (?R) or (?1), when the recursion could match a number of
1211        alternatives. If it matched one of the alternatives, but subsequently,
1212        outside the recursion, there was a failure, the code tried to back up into
1213        the recursion. However, because of the way PCRE is implemented, this is not
1214        possible, and the result was an incorrect result from the match.
1215    
1216        In order to prevent this happening, the specification of recursion has
1217        been changed so that all such subpatterns are automatically treated as
1218        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1219    
1220     4. I had overlooked the fact that, in some locales, there are characters for
1221        which isalpha() is true but neither isupper() nor islower() are true. In
1222        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1223        and ordfeminine) are like this. This affected the treatment of \w and \W
1224        when they appeared in character classes, but not when they appeared outside
1225        a character class. The bit map for "word" characters is now created
1226        separately from the results of isalnum() instead of just taking it from the
1227        upper, lower, and digit maps. (Plus the underscore character, of course.)
1228    
1229     5. The above bug also affected the handling of POSIX character classes such as
1230        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1231        permanent tables. Instead, the bit maps for such a class were previously
1232        created as the appropriate unions of the upper, lower, and digit bitmaps.
1233        Now they are created by subtraction from the [[:word:]] class, which has
1234        its own bitmap.
1235    
1236     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1237        It is created by subtracting the vertical space characters (\x09, \x0a,
1238        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1239        subtraction was done in the overall bitmap for a character class, meaning
1240        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1241        be recognized. This bug has been fixed.
1242    
1243     7. Patches from the folks at Google:
1244    
1245          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1246          real life, but is still worth protecting against".
1247    
1248          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1249          regular expressions".
1250    
1251          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1252          have it.
1253    
1254          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1255          "configure" and the latter not, in order to fix a problem somebody had
1256          with compiling the Arg class on HP-UX.
1257    
1258          (e) Improve the error-handling of the C++ wrapper a little bit.
1259    
1260          (f) New tests for checking recursion limiting.
1261    
1262     8. The pcre_memmove() function, which is used only if the environment does not
1263        have a standard memmove() function (and is therefore rarely compiled),
1264        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1265        returning a result (though PCRE never actually uses the result).
1266    
1267     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1268        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1269        returned instead of calling malloc() with an overflowing number that would
1270        most likely cause subsequent chaos.
1271    
1272    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1273    
1274    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1275        with this option is matched, the nmatch and pmatch options of regexec() are
1276        ignored.
1277    
1278    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1279        provided in case anyone wants to the the POSIX interface with UTF-8
1280        strings.
1281    
1282    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1283        C++ linking (needed for some HP-UX environments).
1284    
1285    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1286        (unused parameter) and in the pcre_printint() function (omitted "default"
1287        switch label when the default is to do nothing).
1288    
1289    15. Added some code to make it possible, when PCRE is compiled as a C++
1290        library, to replace subject pointers for pcre_exec() with a smart pointer
1291        class, thus making it possible to process discontinuous strings.
1292    
1293    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1294        much the same function. They were added by different people who were trying
1295        to make PCRE easy to compile on non-Unix systems. It has been suggested
1296        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1297        for compiling on Windows systems. I have therefore replaced it with
1298        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1299        defaults to "extern" for C or "extern C" for C++, which works fine on
1300        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1301        SCOPE with something explicit in config.h. In addition:
1302    
1303        (a) pcreposix.h still had just "extern" instead of either of these macros;
1304            I have replaced it with PCRE_DATA_SCOPE.
1305    
1306        (b) Functions such as _pcre_xclass(), which are internal to the library,
1307            but external in the C sense, all had PCRE_EXPORT in their definitions.
1308            This is apparently wrong for the Windows case, so I have removed it.
1309            (It makes no difference on Unix-like systems.)
1310    
1311    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1312        of recursive calls to match(). This is different to MATCH_LIMIT because
1313        that limits the total number of calls to match(), not all of which increase
1314        the depth of recursion. Limiting the recursion depth limits the amount of
1315        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1316        when PCRE is compiled, and changed at run time. A patch from Google adds
1317        this functionality to the C++ interface.
1318    
1319    18. Changes to the handling of Unicode character properties:
1320    
1321        (a) Updated the table to Unicode 4.1.0.
1322    
1323        (b) Recognize characters that are not in the table as "Cn" (undefined).
1324    
1325        (c) I revised the way the table is implemented to a much improved format
1326            which includes recognition of ranges. It now supports the ranges that
1327            are defined in UnicodeData.txt, and it also amalgamates other
1328            characters into ranges. This has reduced the number of entries in the
1329            table from around 16,000 to around 3,000, thus reducing its size
1330            considerably. I realized I did not need to use a tree structure after
1331            all - a binary chop search is just as efficient. Having reduced the
1332            number of entries, I extended their size from 6 bytes to 8 bytes to
1333            allow for more data.
1334    
1335        (d) Added support for Unicode script names via properties such as \p{Han}.
1336    
1337    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1338        matching that character.
1339    
1340    20. When matching a repeated Unicode property with a minimum greater than zero,
1341        (for example \pL{2,}), PCRE could look past the end of the subject if it
1342        reached it while seeking the minimum number of characters. This could
1343        happen only if some of the characters were more than one byte long, because
1344        there is a check for at least the minimum number of bytes.
1345    
1346    21. Refactored the implementation of \p and \P so as to be more general, to
1347        allow for more different types of property in future. This has changed the
1348        compiled form incompatibly. Anybody with saved compiled patterns that use
1349        \p or \P will have to recompile them.
1350    
1351    22. Added "Any" and "L&" to the supported property types.
1352    
1353    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1354        but give a compile time error if the value is greater than 0xff.
1355    
1356    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1357        accidentally not being installed or uninstalled.
1358    
1359    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1360        made were to insert the current release number. This seemed silly, because
1361        it made things harder for people building PCRE on systems that don't run
1362        "configure". I have turned pcre.h into a distributed file, no longer built
1363        by "configure", with the version identification directly included. There is
1364        no longer a pcre.h.in file.
1365    
1366        However, this change necessitated a change to the pcre-config script as
1367        well. It is built from pcre-config.in, and one of the substitutions was the
1368        release number. I have updated configure.ac so that ./configure now finds
1369        the release number by grepping pcre.h.
1370    
1371    26. Added the ability to run the tests under valgrind.
1372    
1373    
1374    Version 6.4 05-Sep-05
1375    ---------------------
1376    
1377     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1378        "--" to be printed when multiple files were scanned, even when none of the
1379        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1380        consider it to be a bug, and have restored the previous behaviour.
1381    
1382     2. A couple of code tidies to get rid of compiler warnings.
1383    
1384     3. The pcretest program used to cheat by referring to symbols in the library
1385        whose names begin with _pcre_. These are internal symbols that are not
1386        really supposed to be visible externally, and in some environments it is
1387        possible to suppress them. The cheating is now confined to including
1388        certain files from the library's source, which is a bit cleaner.
1389    
1390     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1391        file's purpose clearer.
1392    
1393     5. Reorganized pcre_ucp_findchar().
1394    
1395    
1396    Version 6.3 15-Aug-05
1397    ---------------------
1398    
1399     1. The file libpcre.pc.in did not have general read permission in the tarball.
1400    
1401     2. There were some problems when building without C++ support:
1402    
1403        (a) If C++ support was not built, "make install" and "make test" still
1404            tried to test it.
1405    
1406        (b) There were problems when the value of CXX was explicitly set. Some
1407            changes have been made to try to fix these, and ...
1408    
1409        (c) --disable-cpp can now be used to explicitly disable C++ support.
1410    
1411        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1412            backslash in a target when C++ was disabled. This confuses some
1413            versions of "make", apparently. Using an intermediate variable solves
1414            this. (Same for CPP_LOBJ.)
1415    
1416     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1417        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1418        necessary on certain architectures.
1419    
1420     4. Added a setting of -export-symbols-regex to the link command to remove
1421        those symbols that are exported in the C sense, but actually are local
1422        within the library, and not documented. Their names all begin with
1423        "_pcre_". This is not a perfect job, because (a) we have to except some
1424        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1425        available (and never for static libraries). I have made a note to try to
1426        find a way round (a) in the future.
1427    
1428    
1429    Version 6.2 01-Aug-05
1430    ---------------------
1431    
1432     1. There was no test for integer overflow of quantifier values. A construction
1433        such as {1111111111111111} would give undefined results. What is worse, if
1434        a minimum quantifier for a parenthesized subpattern overflowed and became
1435        negative, the calculation of the memory size went wrong. This could have
1436        led to memory overwriting.
1437    
1438     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1439    
1440     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1441        operating environments where this matters.
1442    
1443     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1444        PCRE options from within the C++ wrapper.
1445    
1446     5. Named capturing subpatterns were not being correctly counted when a pattern
1447        was compiled. This caused two problems: (a) If there were more than 100
1448        such subpatterns, the calculation of the memory needed for the whole
1449        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1450        back references of the form \12, where the number was greater than 9, were
1451        not recognized as back references, even though there were sufficient
1452        previous subpatterns.
1453    
1454     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1455        versions of gcc, e.g. 2.95.4.
1456    
1457    
1458  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1459  ---------------------  ---------------------
1460    

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