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

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