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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.6 21-Jan-08
5    ---------------------
6    
7    1.  A character class containing a very large number of characters with
8        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9        overflow.
10    
11    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
12        HAVE_LONG_LONG is not defined.
13    
14    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
15        bring them up to date and include new features. This patch includes:
16    
17        - Fixed PH's badly added libz and libbz2 support.
18        - Fixed a problem with static linking.
19        - Added pcredemo.
20        - Fixed dftables problem and added an option.
21        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
22            HAVE_LONG_LONG.
23        - Added readline support for pcretest.
24        - Added an listing of the option settings after cmake has run.
25    
26    4.  A user submitted a patch to Makefile that makes it easy to created a dll
27        under mingw. I added stuff to Makefile.am that cause it to include this
28        special target, without affecting anything else.
29    
30    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
31        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
32        exported in the Windows port". It has not yet been confirmed that the patch
33        solves the problem, but it does no harm.
34    
35    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
36        NON_STANDARD_LIB_SUFFIX and correct the comment about stack recursion.
37    
38    
39    Version 7.5 10-Jan-08
40    ---------------------
41    
42    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
43        values in parens when parsing an RE using the C++ wrapper."
44    
45    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
46        Characters greater than 255 were excluded from the class instead of being
47        included.
48    
49    3.  The same bug as (2) above applied to negated POSIX classes such as
50        [:^space:].
51    
52    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
53        defined or documented. It seems to have been a typo for PCRE_STATIC, so
54        I have changed it.
55    
56    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
57        first named subpattern) and a construct such as (?&a) would reference the
58        first named subpattern whose name started with "a" (in other words, the
59        length check was missing). Both these problems are fixed. "Subpattern name
60        expected" is now given for (?&) (a zero-length name), and this patch also
61        makes it give the same error for \k'' (previously it complained that that
62        was a reference to a non-existent subpattern).
63    
64    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
65        this is right because (?- can be followed by option settings as well as by
66        digits. I have, however, made the messages clearer.
67    
68    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
69        than the number used in the conditional) now cause a compile-time error.
70        This is actually not compatible with Perl, which accepts such patterns, but
71        treats the conditional as always being FALSE (as PCRE used to), but it
72        seems to me that giving a diagnostic is better.
73    
74    8.  Change "alphameric" to the more common word "alphanumeric" in comments
75        and messages.
76    
77    9.  Fix two occurrences of "backslash" in comments that should have been
78        "backspace".
79    
80    10. Remove two redundant lines of code that can never be obeyed (their function
81        was moved elsewhere).
82    
83    11. The program that makes PCRE's Unicode character property table had a bug
84        which caused it to generate incorrect table entries for sequences of
85        characters that have the same character type, but are in different scripts.
86        It amalgamated them into a single range, with the script of the first of
87        them. In other words, some characters were in the wrong script. There were
88        thirteen such cases, affecting characters in the following ranges:
89    
90          U+002b0 - U+002c1
91          U+0060c - U+0060d
92          U+0061e - U+00612
93          U+0064b - U+0065e
94          U+0074d - U+0076d
95          U+01800 - U+01805
96          U+01d00 - U+01d77
97          U+01d9b - U+01dbf
98          U+0200b - U+0200f
99          U+030fc - U+030fe
100          U+03260 - U+0327f
101          U+0fb46 - U+0fbb1
102          U+10450 - U+1049d
103    
104    12. The -o option (show only the matching part of a line) for pcregrep was not
105        compatible with GNU grep in that, if there was more than one match in a
106        line, it showed only the first of them. It now behaves in the same way as
107        GNU grep.
108    
109    13. If the -o and -v options were combined for pcregrep, it printed a blank
110        line for every non-matching line. GNU grep prints nothing, and pcregrep now
111        does the same. The return code can be used to tell if there were any
112        non-matching lines.
113    
114    14. Added --file-offsets and --line-offsets to pcregrep.
115    
116    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
117        infinitely looping recursion. The bug was that positive lookaheads were not
118        being skipped when checking for a possible empty match (negative lookaheads
119        and both kinds of lookbehind were skipped).
120    
121    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
122        inclusion of <windows.h> to before rather than after the definition of
123        INVALID_FILE_ATTRIBUTES (patch from David Byron).
124    
125    17. Specifying a possessive quantifier with a specific limit for a Unicode
126        character property caused pcre_compile() to compile bad code, which led at
127        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
128        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
129        caused the error; without that there was no problem.
130    
131    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
132    
133    19. Added --enable-pcretest-libreadline.
134    
135    20. In pcrecpp.cc, the variable 'count' was incremented twice in
136        RE::GlobalReplace(). As a result, the number of replacements returned was
137        double what it should be. I removed one of the increments, but Craig sent a
138        later patch that removed the other one (the right fix) and added unit tests
139        that check the return values (which was not done before).
140    
141    21. Several CMake things:
142    
143        (1) Arranged that, when cmake is used on Unix, the libraries end up with
144            the names libpcre and libpcreposix, not just pcre and pcreposix.
145    
146        (2) The above change means that pcretest and pcregrep are now correctly
147            linked with the newly-built libraries, not previously installed ones.
148    
149        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
150    
151    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
152        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
153        UTF-8 newline character). The key issue is that the pattern starts .*;
154        this means that the match must be either at the beginning, or after a
155        newline. The bug was in the code for advancing after a failed match and
156        checking that the new position followed a newline. It was not taking
157        account of UTF-8 characters correctly.
158    
159    23. PCRE was behaving differently from Perl in the way it recognized POSIX
160        character classes. PCRE was not treating the sequence [:...:] as a
161        character class unless the ... were all letters. Perl, however, seems to
162        allow any characters between [: and :], though of course it rejects as
163        unknown any "names" that contain non-letters, because all the known class
164        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
165        for example, whereas PCRE did not - it did not recognize a POSIX character
166        class. This seemed a bit dangerous, so the code has been changed to be
167        closer to Perl. The behaviour is not identical to Perl, because PCRE will
168        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
169        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
170        Perl does, and where it didn't before.
171    
172    24. Rewrite so as to remove the single use of %n from pcregrep because in some
173        Windows environments %n is disabled by default.
174    
175    
176    Version 7.4 21-Sep-07
177    ---------------------
178    
179    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
180        means that a class such as [\s] counted as "explicit reference to CR or
181        LF". That isn't really right - the whole point of the change was to try to
182        help when there was an actual mention of one of the two characters. So now
183        the change happens only if \r or \n (or a literal CR or LF) character is
184        encountered.
185    
186    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
187        of both had grown to the point where there were only 3 bits left.
188        Fortunately, there was spare space in the data structure, and so I have
189        moved the internal flags into a new 16-bit field to free up more option
190        bits.
191    
192    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
193        but did not set the internal JCHANGED flag - either of these is enough to
194        control the way the "get" function works - but the PCRE_INFO_JCHANGED
195        facility is supposed to tell if (?J) was ever used, so now (?J) at the
196        start sets both bits.
197    
198    4.  Added options (at build time, compile time, exec time) to change \R from
199        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
200    
201    5.  doc/pcresyntax.html was missing from the distribution.
202    
203    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
204        compatibility, even though it is no longer used.
205    
206    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
207        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
208        windows.h file is present (where different names are used). [This was
209        reversed later after testing - see 16 below.]
210    
211    8.  Changed all #include <config.h> to #include "config.h". There were also
212        some further <pcre.h> cases that I changed to "pcre.h".
213    
214    9.  When pcregrep was used with the --colour option, it missed the line ending
215        sequence off the lines that it output.
216    
217    10. It was pointed out to me that arrays of string pointers cause lots of
218        relocations when a shared library is dynamically loaded. A technique of
219        using a single long string with a table of offsets can drastically reduce
220        these. I have refactored PCRE in four places to do this. The result is
221        dramatic:
222    
223          Originally:                          290
224          After changing UCP table:            187
225          After changing error message table:   43
226          After changing table of "verbs"       36
227          After changing table of Posix names   22
228    
229        Thanks to the folks working on Gregex for glib for this insight.
230    
231    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
232        unicode-properties was also set.
233    
234    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
235    
236    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
237        checked only for CRLF.
238    
239    14. Added casts to pcretest.c to avoid compiler warnings.
240    
241    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
242    
243    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
244        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
245        entirely. This removes changes made in 7 above.
246    
247    17. The CMake files have been updated, and there is now more information about
248        building with CMake in the NON-UNIX-USE document.
249    
250    
251    Version 7.3 28-Aug-07
252    ---------------------
253    
254     1. In the rejigging of the build system that eventually resulted in 7.1, the
255        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
256        brackets there is not right, since it causes compilers to look for an
257        installed pcre.h, not the version that is in the source that is being
258        compiled (which of course may be different). I have changed it back to:
259    
260          #include "pcre.h"
261    
262        I have a vague recollection that the change was concerned with compiling in
263        different directories, but in the new build system, that is taken care of
264        by the VPATH setting the Makefile.
265    
266     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
267        when the subject happened to end in the byte 0x85 (e.g. if the last
268        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
269        characters but of course it shouldn't be taken as a newline when it is part
270        of another character. The bug was that, for an unlimited repeat of . in
271        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
272        characters when looking for a newline.
273    
274     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
275    
276     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
277        in debug output.
278    
279     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
280        long printing in the pcrecpp unittest when running under MinGW.
281    
282     6. ESC_K was left out of the EBCDIC table.
283    
284     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
285        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
286        limit also applies to "virtual nesting" when a pattern is recursive, and in
287        this case 1000 isn't so big. I have been able to remove this limit at the
288        expense of backing off one optimization in certain circumstances. Normally,
289        when pcre_exec() would call its internal match() function recursively and
290        immediately return the result unconditionally, it uses a "tail recursion"
291        feature to save stack. However, when a subpattern that can match an empty
292        string has an unlimited repetition quantifier, it no longer makes this
293        optimization. That gives it a stack frame in which to save the data for
294        checking that an empty string has been matched. Previously this was taken
295        from the 1000-entry workspace that had been reserved. So now there is no
296        explicit limit, but more stack is used.
297    
298     8. Applied Daniel's patches to solve problems with the import/export magic
299        syntax that is required for Windows, and which was going wrong for the
300        pcreposix and pcrecpp parts of the library. These were overlooked when this
301        problem was solved for the main library.
302    
303     9. There were some crude static tests to avoid integer overflow when computing
304        the size of patterns that contain repeated groups with explicit upper
305        limits. As the maximum quantifier is 65535, the maximum group length was
306        set at 30,000 so that the product of these two numbers did not overflow a
307        32-bit integer. However, it turns out that people want to use groups that
308        are longer than 30,000 bytes (though not repeat them that many times).
309        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
310        made it possible to implement the integer overflow checks in a much more
311        dynamic way, which I have now done. The artificial limitation on group
312        length has been removed - we now have only the limit on the total length of
313        the compiled pattern, which depends on the LINK_SIZE setting.
314    
315    10. Fixed a bug in the documentation for get/copy named substring when
316        duplicate names are permitted. If none of the named substrings are set, the
317        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
318        empty string.
319    
320    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
321        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
322        because the ] is interpreted as the first data character and the
323        terminating ] is not found. PCRE has been made compatible with Perl in this
324        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
325        cause memory overwriting.
326    
327    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
328        string has been matched (to stop an infinite loop). It was not recognizing
329        a conditional subpattern that could match an empty string if that
330        subpattern was within another subpattern. For example, it looped when
331        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
332        condition was not nested. This bug has been fixed.
333    
334    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
335        past the start of the subject in the presence of bytes with the top bit
336        set, for example "\x8aBCD".
337    
338    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
339        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
340    
341    14. Optimized (?!) to (*FAIL).
342    
343    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
344        This restricts code points to be within the range 0 to 0x10FFFF, excluding
345        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
346        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
347        does: it's just the validity check that is more restrictive.
348    
349    16. Inserted checks for integer overflows during escape sequence (backslash)
350        processing, and also fixed erroneous offset values for syntax errors during
351        backslash processing.
352    
353    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
354        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
355    
356    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
357        caused an overrun.
358    
359    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
360        something other than just ASCII characters) inside a group that had an
361        unlimited repeat caused a loop at compile time (while checking to see
362        whether the group could match an empty string).
363    
364    20. Debugging a pattern containing \p or \P could cause a crash. For example,
365        [\P{Any}] did so. (Error in the code for printing property names.)
366    
367    21. An orphan \E inside a character class could cause a crash.
368    
369    22. A repeated capturing bracket such as (A)? could cause a wild memory
370        reference during compilation.
371    
372    23. There are several functions in pcre_compile() that scan along a compiled
373        expression for various reasons (e.g. to see if it's fixed length for look
374        behind). There were bugs in these functions when a repeated \p or \P was
375        present in the pattern. These operators have additional parameters compared
376        with \d, etc, and these were not being taken into account when moving along
377        the compiled data. Specifically:
378    
379        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
380            length.
381    
382        (b) An item such as \pL+ within a repeated group could cause crashes or
383            loops.
384    
385        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
386            "reference to non-existent subpattern" error.
387    
388        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
389    
390    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
391        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
392    
393    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
394    
395    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
396        character were causing crashes (broken optimization).
397    
398    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
399        \p or \P) caused a compile-time loop.
400    
401    28. More problems have arisen in unanchored patterns when CRLF is a valid line
402        break. For example, the unstudied pattern [\r\n]A does not match the string
403        "\r\nA" because change 7.0/46 below moves the current point on by two
404        characters after failing to match at the start. However, the pattern \nA
405        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
406        the same is true. There doesn't seem any very clean way out of this, but
407        what I have chosen to do makes the common cases work: PCRE now takes note
408        of whether there can be an explicit match for \r or \n anywhere in the
409        pattern, and if so, 7.0/46 no longer applies. As part of this change,
410        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
411        pattern has explicit CR or LF references.
412    
413    29. Added (*CR) etc for changing newline setting at start of pattern.
414    
415    
416    Version 7.2 19-Jun-07
417    ---------------------
418    
419     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
420        which is apparently normally available under Windows.
421    
422     2. Re-jig the pcregrep tests with different newline settings in an attempt
423        to make them independent of the local environment's newline setting.
424    
425     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
426    
427     4. Some of the "internals" tests were previously cut out when the link size
428        was not 2, because the output contained actual offsets. The recent new
429        "Z" feature of pcretest means that these can be cut out, making the tests
430        usable with all link sizes.
431    
432     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
433        stack recursion. This gives a massive performance boost under BSD, but just
434        a small improvement under Linux. However, it saves one field in the frame
435        in all cases.
436    
437     6. Added more features from the forthcoming Perl 5.10:
438    
439        (a) (?-n) (where n is a string of digits) is a relative subroutine or
440            recursion call. It refers to the nth most recently opened parentheses.
441    
442        (b) (?+n) is also a relative subroutine call; it refers to the nth next
443            to be opened parentheses.
444    
445        (c) Conditions that refer to capturing parentheses can be specified
446            relatively, for example, (?(-2)... or (?(+3)...
447    
448        (d) \K resets the start of the current match so that everything before
449            is not part of it.
450    
451        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
452    
453        (f) \g{name} is another synonym - part of Perl 5.10's unification of
454            reference syntax.
455    
456        (g) (?| introduces a group in which the numbering of parentheses in each
457            alternative starts with the same number.
458    
459        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
460    
461     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
462        PCRE_INFO_JCHANGED.
463    
464     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
465        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
466        for detecting groups that can match an empty string.
467    
468     9. A pattern with a very large number of alternatives (more than several
469        hundred) was running out of internal workspace during the pre-compile
470        phase, where pcre_compile() figures out how much memory will be needed. A
471        bit of new cunning has reduced the workspace needed for groups with
472        alternatives. The 1000-alternative test pattern now uses 12 bytes of
473        workspace instead of running out of the 4096 that are available.
474    
475    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
476    
477    11. Applied patch from Google to remove an optimization that didn't quite work.
478        The report of the bug said:
479    
480          pcrecpp::RE("a*").FullMatch("aaa") matches, while
481          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
482          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
483    
484    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
485        it matched the wrong number of bytes.
486    
487    
488  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
489  ---------------------  ---------------------
490    

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