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

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