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revision 150 by ph10, Tue Apr 17 08:22:40 2007 UTC revision 319 by ph10, Mon Jan 28 15:27:45 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 7.6 28-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. [But later removed - see 7 below.]
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 create
27        "pcre.dll" under mingw when using Configure/Make. I added stuff to
28        Makefile.am that cause it to include this special target, without
29        affecting anything else. Note that the same mingw target plus all
30        the other distribution libraries and programs are now supported
31        when configuring with CMake (see 6 below) instead of with
32        Configure/Make.
33    
34    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
35        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
36        exported in the Windows port". It has not yet been confirmed that the patch
37        solves the problem, but it does no harm.
38    
39    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
40        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
41        with CMake, and also correct the comment about stack recursion.
42    
43    7.  Remove the automatic building of pcredemo from the ./configure system and
44        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
45        of a program that users should build themselves after PCRE is installed, so
46        building it automatically is not really right. What is more, it gave
47        trouble in some build environments.
48    
49    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
50    
51    
52    Version 7.5 10-Jan-08
53    ---------------------
54    
55    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
56        values in parens when parsing an RE using the C++ wrapper."
57    
58    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
59        Characters greater than 255 were excluded from the class instead of being
60        included.
61    
62    3.  The same bug as (2) above applied to negated POSIX classes such as
63        [:^space:].
64    
65    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
66        defined or documented. It seems to have been a typo for PCRE_STATIC, so
67        I have changed it.
68    
69    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
70        first named subpattern) and a construct such as (?&a) would reference the
71        first named subpattern whose name started with "a" (in other words, the
72        length check was missing). Both these problems are fixed. "Subpattern name
73        expected" is now given for (?&) (a zero-length name), and this patch also
74        makes it give the same error for \k'' (previously it complained that that
75        was a reference to a non-existent subpattern).
76    
77    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
78        this is right because (?- can be followed by option settings as well as by
79        digits. I have, however, made the messages clearer.
80    
81    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
82        than the number used in the conditional) now cause a compile-time error.
83        This is actually not compatible with Perl, which accepts such patterns, but
84        treats the conditional as always being FALSE (as PCRE used to), but it
85        seems to me that giving a diagnostic is better.
86    
87    8.  Change "alphameric" to the more common word "alphanumeric" in comments
88        and messages.
89    
90    9.  Fix two occurrences of "backslash" in comments that should have been
91        "backspace".
92    
93    10. Remove two redundant lines of code that can never be obeyed (their function
94        was moved elsewhere).
95    
96    11. The program that makes PCRE's Unicode character property table had a bug
97        which caused it to generate incorrect table entries for sequences of
98        characters that have the same character type, but are in different scripts.
99        It amalgamated them into a single range, with the script of the first of
100        them. In other words, some characters were in the wrong script. There were
101        thirteen such cases, affecting characters in the following ranges:
102    
103          U+002b0 - U+002c1
104          U+0060c - U+0060d
105          U+0061e - U+00612
106          U+0064b - U+0065e
107          U+0074d - U+0076d
108          U+01800 - U+01805
109          U+01d00 - U+01d77
110          U+01d9b - U+01dbf
111          U+0200b - U+0200f
112          U+030fc - U+030fe
113          U+03260 - U+0327f
114          U+0fb46 - U+0fbb1
115          U+10450 - U+1049d
116    
117    12. The -o option (show only the matching part of a line) for pcregrep was not
118        compatible with GNU grep in that, if there was more than one match in a
119        line, it showed only the first of them. It now behaves in the same way as
120        GNU grep.
121    
122    13. If the -o and -v options were combined for pcregrep, it printed a blank
123        line for every non-matching line. GNU grep prints nothing, and pcregrep now
124        does the same. The return code can be used to tell if there were any
125        non-matching lines.
126    
127    14. Added --file-offsets and --line-offsets to pcregrep.
128    
129    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
130        infinitely looping recursion. The bug was that positive lookaheads were not
131        being skipped when checking for a possible empty match (negative lookaheads
132        and both kinds of lookbehind were skipped).
133    
134    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
135        inclusion of <windows.h> to before rather than after the definition of
136        INVALID_FILE_ATTRIBUTES (patch from David Byron).
137    
138    17. Specifying a possessive quantifier with a specific limit for a Unicode
139        character property caused pcre_compile() to compile bad code, which led at
140        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
141        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
142        caused the error; without that there was no problem.
143    
144    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
145    
146    19. Added --enable-pcretest-libreadline.
147    
148    20. In pcrecpp.cc, the variable 'count' was incremented twice in
149        RE::GlobalReplace(). As a result, the number of replacements returned was
150        double what it should be. I removed one of the increments, but Craig sent a
151        later patch that removed the other one (the right fix) and added unit tests
152        that check the return values (which was not done before).
153    
154    21. Several CMake things:
155    
156        (1) Arranged that, when cmake is used on Unix, the libraries end up with
157            the names libpcre and libpcreposix, not just pcre and pcreposix.
158    
159        (2) The above change means that pcretest and pcregrep are now correctly
160            linked with the newly-built libraries, not previously installed ones.
161    
162        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
163    
164    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
165        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
166        UTF-8 newline character). The key issue is that the pattern starts .*;
167        this means that the match must be either at the beginning, or after a
168        newline. The bug was in the code for advancing after a failed match and
169        checking that the new position followed a newline. It was not taking
170        account of UTF-8 characters correctly.
171    
172    23. PCRE was behaving differently from Perl in the way it recognized POSIX
173        character classes. PCRE was not treating the sequence [:...:] as a
174        character class unless the ... were all letters. Perl, however, seems to
175        allow any characters between [: and :], though of course it rejects as
176        unknown any "names" that contain non-letters, because all the known class
177        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
178        for example, whereas PCRE did not - it did not recognize a POSIX character
179        class. This seemed a bit dangerous, so the code has been changed to be
180        closer to Perl. The behaviour is not identical to Perl, because PCRE will
181        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
182        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
183        Perl does, and where it didn't before.
184    
185    24. Rewrite so as to remove the single use of %n from pcregrep because in some
186        Windows environments %n is disabled by default.
187    
188    
189    Version 7.4 21-Sep-07
190    ---------------------
191    
192    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
193        means that a class such as [\s] counted as "explicit reference to CR or
194        LF". That isn't really right - the whole point of the change was to try to
195        help when there was an actual mention of one of the two characters. So now
196        the change happens only if \r or \n (or a literal CR or LF) character is
197        encountered.
198    
199    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
200        of both had grown to the point where there were only 3 bits left.
201        Fortunately, there was spare space in the data structure, and so I have
202        moved the internal flags into a new 16-bit field to free up more option
203        bits.
204    
205    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
206        but did not set the internal JCHANGED flag - either of these is enough to
207        control the way the "get" function works - but the PCRE_INFO_JCHANGED
208        facility is supposed to tell if (?J) was ever used, so now (?J) at the
209        start sets both bits.
210    
211    4.  Added options (at build time, compile time, exec time) to change \R from
212        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
213    
214    5.  doc/pcresyntax.html was missing from the distribution.
215    
216    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
217        compatibility, even though it is no longer used.
218    
219    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
220        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
221        windows.h file is present (where different names are used). [This was
222        reversed later after testing - see 16 below.]
223    
224    8.  Changed all #include <config.h> to #include "config.h". There were also
225        some further <pcre.h> cases that I changed to "pcre.h".
226    
227    9.  When pcregrep was used with the --colour option, it missed the line ending
228        sequence off the lines that it output.
229    
230    10. It was pointed out to me that arrays of string pointers cause lots of
231        relocations when a shared library is dynamically loaded. A technique of
232        using a single long string with a table of offsets can drastically reduce
233        these. I have refactored PCRE in four places to do this. The result is
234        dramatic:
235    
236          Originally:                          290
237          After changing UCP table:            187
238          After changing error message table:   43
239          After changing table of "verbs"       36
240          After changing table of Posix names   22
241    
242        Thanks to the folks working on Gregex for glib for this insight.
243    
244    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
245        unicode-properties was also set.
246    
247    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
248    
249    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
250        checked only for CRLF.
251    
252    14. Added casts to pcretest.c to avoid compiler warnings.
253    
254    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
255    
256    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
257        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
258        entirely. This removes changes made in 7 above.
259    
260    17. The CMake files have been updated, and there is now more information about
261        building with CMake in the NON-UNIX-USE document.
262    
263    
264    Version 7.3 28-Aug-07
265    ---------------------
266    
267     1. In the rejigging of the build system that eventually resulted in 7.1, the
268        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
269        brackets there is not right, since it causes compilers to look for an
270        installed pcre.h, not the version that is in the source that is being
271        compiled (which of course may be different). I have changed it back to:
272    
273          #include "pcre.h"
274    
275        I have a vague recollection that the change was concerned with compiling in
276        different directories, but in the new build system, that is taken care of
277        by the VPATH setting the Makefile.
278    
279     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
280        when the subject happened to end in the byte 0x85 (e.g. if the last
281        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
282        characters but of course it shouldn't be taken as a newline when it is part
283        of another character. The bug was that, for an unlimited repeat of . in
284        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
285        characters when looking for a newline.
286    
287     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
288    
289     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
290        in debug output.
291    
292     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
293        long printing in the pcrecpp unittest when running under MinGW.
294    
295     6. ESC_K was left out of the EBCDIC table.
296    
297     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
298        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
299        limit also applies to "virtual nesting" when a pattern is recursive, and in
300        this case 1000 isn't so big. I have been able to remove this limit at the
301        expense of backing off one optimization in certain circumstances. Normally,
302        when pcre_exec() would call its internal match() function recursively and
303        immediately return the result unconditionally, it uses a "tail recursion"
304        feature to save stack. However, when a subpattern that can match an empty
305        string has an unlimited repetition quantifier, it no longer makes this
306        optimization. That gives it a stack frame in which to save the data for
307        checking that an empty string has been matched. Previously this was taken
308        from the 1000-entry workspace that had been reserved. So now there is no
309        explicit limit, but more stack is used.
310    
311     8. Applied Daniel's patches to solve problems with the import/export magic
312        syntax that is required for Windows, and which was going wrong for the
313        pcreposix and pcrecpp parts of the library. These were overlooked when this
314        problem was solved for the main library.
315    
316     9. There were some crude static tests to avoid integer overflow when computing
317        the size of patterns that contain repeated groups with explicit upper
318        limits. As the maximum quantifier is 65535, the maximum group length was
319        set at 30,000 so that the product of these two numbers did not overflow a
320        32-bit integer. However, it turns out that people want to use groups that
321        are longer than 30,000 bytes (though not repeat them that many times).
322        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
323        made it possible to implement the integer overflow checks in a much more
324        dynamic way, which I have now done. The artificial limitation on group
325        length has been removed - we now have only the limit on the total length of
326        the compiled pattern, which depends on the LINK_SIZE setting.
327    
328    10. Fixed a bug in the documentation for get/copy named substring when
329        duplicate names are permitted. If none of the named substrings are set, the
330        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
331        empty string.
332    
333    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
334        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
335        because the ] is interpreted as the first data character and the
336        terminating ] is not found. PCRE has been made compatible with Perl in this
337        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
338        cause memory overwriting.
339    
340    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
341        string has been matched (to stop an infinite loop). It was not recognizing
342        a conditional subpattern that could match an empty string if that
343        subpattern was within another subpattern. For example, it looped when
344        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
345        condition was not nested. This bug has been fixed.
346    
347    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
348        past the start of the subject in the presence of bytes with the top bit
349        set, for example "\x8aBCD".
350    
351    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
352        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
353    
354    14. Optimized (?!) to (*FAIL).
355    
356    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
357        This restricts code points to be within the range 0 to 0x10FFFF, excluding
358        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
359        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
360        does: it's just the validity check that is more restrictive.
361    
362    16. Inserted checks for integer overflows during escape sequence (backslash)
363        processing, and also fixed erroneous offset values for syntax errors during
364        backslash processing.
365    
366    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
367        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
368    
369    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
370        caused an overrun.
371    
372    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
373        something other than just ASCII characters) inside a group that had an
374        unlimited repeat caused a loop at compile time (while checking to see
375        whether the group could match an empty string).
376    
377    20. Debugging a pattern containing \p or \P could cause a crash. For example,
378        [\P{Any}] did so. (Error in the code for printing property names.)
379    
380    21. An orphan \E inside a character class could cause a crash.
381    
382    22. A repeated capturing bracket such as (A)? could cause a wild memory
383        reference during compilation.
384    
385    23. There are several functions in pcre_compile() that scan along a compiled
386        expression for various reasons (e.g. to see if it's fixed length for look
387        behind). There were bugs in these functions when a repeated \p or \P was
388        present in the pattern. These operators have additional parameters compared
389        with \d, etc, and these were not being taken into account when moving along
390        the compiled data. Specifically:
391    
392        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
393            length.
394    
395        (b) An item such as \pL+ within a repeated group could cause crashes or
396            loops.
397    
398        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
399            "reference to non-existent subpattern" error.
400    
401        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
402    
403    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
404        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
405    
406    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
407    
408    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
409        character were causing crashes (broken optimization).
410    
411    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
412        \p or \P) caused a compile-time loop.
413    
414    28. More problems have arisen in unanchored patterns when CRLF is a valid line
415        break. For example, the unstudied pattern [\r\n]A does not match the string
416        "\r\nA" because change 7.0/46 below moves the current point on by two
417        characters after failing to match at the start. However, the pattern \nA
418        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
419        the same is true. There doesn't seem any very clean way out of this, but
420        what I have chosen to do makes the common cases work: PCRE now takes note
421        of whether there can be an explicit match for \r or \n anywhere in the
422        pattern, and if so, 7.0/46 no longer applies. As part of this change,
423        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
424        pattern has explicit CR or LF references.
425    
426    29. Added (*CR) etc for changing newline setting at start of pattern.
427    
428    
429    Version 7.2 19-Jun-07
430    ---------------------
431    
432     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
433        which is apparently normally available under Windows.
434    
435     2. Re-jig the pcregrep tests with different newline settings in an attempt
436        to make them independent of the local environment's newline setting.
437    
438     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
439    
440     4. Some of the "internals" tests were previously cut out when the link size
441        was not 2, because the output contained actual offsets. The recent new
442        "Z" feature of pcretest means that these can be cut out, making the tests
443        usable with all link sizes.
444    
445     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
446        stack recursion. This gives a massive performance boost under BSD, but just
447        a small improvement under Linux. However, it saves one field in the frame
448        in all cases.
449    
450     6. Added more features from the forthcoming Perl 5.10:
451    
452        (a) (?-n) (where n is a string of digits) is a relative subroutine or
453            recursion call. It refers to the nth most recently opened parentheses.
454    
455        (b) (?+n) is also a relative subroutine call; it refers to the nth next
456            to be opened parentheses.
457    
458        (c) Conditions that refer to capturing parentheses can be specified
459            relatively, for example, (?(-2)... or (?(+3)...
460    
461        (d) \K resets the start of the current match so that everything before
462            is not part of it.
463    
464        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
465    
466        (f) \g{name} is another synonym - part of Perl 5.10's unification of
467            reference syntax.
468    
469        (g) (?| introduces a group in which the numbering of parentheses in each
470            alternative starts with the same number.
471    
472        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
473    
474     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
475        PCRE_INFO_JCHANGED.
476    
477     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
478        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
479        for detecting groups that can match an empty string.
480    
481     9. A pattern with a very large number of alternatives (more than several
482        hundred) was running out of internal workspace during the pre-compile
483        phase, where pcre_compile() figures out how much memory will be needed. A
484        bit of new cunning has reduced the workspace needed for groups with
485        alternatives. The 1000-alternative test pattern now uses 12 bytes of
486        workspace instead of running out of the 4096 that are available.
487    
488    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
489    
490    11. Applied patch from Google to remove an optimization that didn't quite work.
491        The report of the bug said:
492    
493          pcrecpp::RE("a*").FullMatch("aaa") matches, while
494          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
495          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
496    
497    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
498        it matched the wrong number of bytes.
499    
500    
501    Version 7.1 24-Apr-07
502  ---------------------  ---------------------
503    
504   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 143  Version 7.1 12-Mar-07 Line 640  Version 7.1 12-Mar-07
640  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
641      CRLF as a newline sequence.      CRLF as a newline sequence.
642    
643    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
644        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
645        I have nevertheless tidied it up.
646    
647    23. Added some casts to kill warnings from HP-UX ia64 compiler.
648    
649    24. Added a man page for pcre-config.
650    
651    
652  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
653  ---------------------  ---------------------

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