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revision 432 by ph10, Wed Sep 2 16:02:56 2009 UTC revision 498 by ph10, Wed Mar 3 19:29:38 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.02 01-Mar-2010
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
8    
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
11    
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
14    
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
17    
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
22    
23    6.  Both MS Visual Studio and Symbian OS have problems with initializing
24        variables to point to external functions. For these systems, therefore,
25        pcre_malloc etc. are now initialized to local functions that call the
26        relevant global functions.
27    
28    7.  There were two entries missing in the vectors called coptable and poptable
29        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
30        I've fixed the data, and added a kludgy way of testing at compile time that
31        the lengths are correct (equal to the number of opcodes).
32    
33    
34    Version 8.01 19-Jan-2010
35    ------------------------
36    
37    1.  If a pattern contained a conditional subpattern with only one branch (in
38        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
39        computed the wrong minimum data length (which is of course zero for such
40        subpatterns). This could cause incorrect "no match" results.
41    
42    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
43        the pattern is reset in the first branch, pcre_compile() failed with
44        "internal error: code overflow at offset...". This happened only when
45        the reset was to the original external option setting. (An optimization
46        abstracts leading options settings into an external setting, which was the
47        cause of this.)
48    
49    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
50        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
51        assertion pattern did not match (meaning that the assertion was true), it
52        was incorrectly treated as false if the SKIP had been reached during the
53        matching. This also applied to assertions used as conditions.
54    
55    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
56        assertion subpattern, including such a pattern used as a condition,
57        unpredictable results occurred, instead of the error return
58        PCRE_ERROR_DFA_UITEM.
59    
60    5.  The C++ GlobalReplace function was not working like Perl for the special
61        situation when an empty string is matched. It now does the fancy magic
62        stuff that is necessary.
63    
64    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
65        removed. (These were left over from very, very early versions of PCRE.)
66    
67    7.  Some cosmetic changes to the code to make life easier when compiling it
68        as part of something else:
69    
70        (a) Change DEBUG to PCRE_DEBUG.
71    
72        (b) In pcre_compile(), rename the member of the "branch_chain" structure
73            called "current" as "current_branch", to prevent a collision with the
74            Linux macro when compiled as a kernel module.
75    
76        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
77            prevent a collision with the Linux macro when compiled as a kernel
78            module.
79    
80    8.  In pcre_compile() there are some checks for integer overflows that used to
81        cast potentially large values to (double). This has been changed to that
82        when building, a check for int64_t is made, and if it is found, it is used
83        instead, thus avoiding the use of floating point arithmetic. (There is no
84        other use of FP in PCRE.) If int64_t is not found, the fallback is to
85        double.
86    
87    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
88        2005 (difference between two addresses compared to an unsigned value).
89    
90    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
91        custom one, because of the following reported problem in Windows:
92    
93          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
94              under Win32.
95          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
96              therefore missing the function definition.
97          - The compiler thus generates a "C" signature for the test function.
98          - The linker fails to find the "C" function.
99          - PCRE fails to configure if asked to do so against libbz2.
100    
101    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
102        messages were output:
103    
104          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
105          rerunning libtoolize, to keep the correct libtool macros in-tree.
106          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
107    
108        I have done both of these things.
109    
110    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
111        most of the time, it *can* run out if it is given a pattern that contains a
112        runaway infinite recursion. I updated the discussion in the pcrestack man
113        page.
114    
115    13. Now that we have gone to the x.xx style of version numbers, the minor
116        version may start with zero. Using 08 or 09 is a bad idea because users
117        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
118        interpreted as invalid octal numbers. I've updated the previous comment in
119        configure.ac, and also added a check that gives an error if 08 or 09 are
120        used.
121    
122    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
123        causing partial matching to fail when the end of the subject matched \W
124        in a UTF-8 pattern where \W was quantified with a minimum of 3.
125    
126    15. There were some discrepancies between the declarations in pcre_internal.h
127        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
128        their definitions. The declarations used "const uschar *" and the
129        definitions used USPTR. Even though USPTR is normally defined as "const
130        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
131        reported that: "This difference in casting confuses some C++ compilers, for
132        example, SunCC recognizes above declarations as different functions and
133        generates broken code for hbpcre." I have changed the declarations to use
134        USPTR.
135    
136    16. GNU libtool is named differently on some systems. The autogen.sh script now
137        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
138        (FreeBSD).
139    
140    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
141        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
142        comment: "Figure out how to create a longlong from a string: strtoll and
143        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
144        instance, but it only takes 2 args instead of 3!"
145    
146    18. A subtle bug concerned with back references has been fixed by a change of
147        specification, with a corresponding code fix. A pattern such as
148        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
149        refers, was giving matches when it shouldn't. For example, xa=xaaa would
150        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
151        same bug. Such groups have to be quantified to be useful, or contained
152        inside another quantified group. (If there's no repetition, the reference
153        can never match.) The problem arises because, having left the group and
154        moved on to the rest of the pattern, a later failure that backtracks into
155        the group uses the captured value from the final iteration of the group
156        rather than the correct earlier one. I have fixed this in PCRE by forcing
157        any group that contains a reference to itself to be an atomic group; that
158        is, there cannot be any backtracking into it once it has completed. This is
159        similar to recursive and subroutine calls.
160    
161    
162    Version 8.00 19-Oct-09
163  ----------------------  ----------------------
164    
165  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
166      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
167      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
168      error.      error.
169    
170  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
171      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
172      in a Windows environment.      in a Windows environment.
173    
174  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
175      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
176      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
177      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
178      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
179      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
180      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
181    
182  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
183      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
184      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
185      the old behaviour.      the old behaviour.
186    
187  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
188      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
189      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
190      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
191    
192  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
193      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
194    
195  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
196      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
197      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
198      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
199      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
200      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
201    
202  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
203      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
204      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
205      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
206      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
207      result.      result.
208    
209  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
210      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
211      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
212      slots in the offset vector, the offsets of the first-encountered partial      slots in the offset vector, the offset of the earliest inspected character
213      match are set in them when PCRE_ERROR_PARTIAL is returned.      for the match and the offset of the end of the subject are set in them when
214        PCRE_ERROR_PARTIAL is returned.
215    
216  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
217      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
218      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
219      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
220      pcre_exec().  
221    11. Partial matching with pcre_exec() is now more intuitive. A partial match
222  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
223      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
224      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
225      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
226      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
227      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
228      final character ended with (*FAIL).  
   
229  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
230      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
231      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
232      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
233      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
234      "sbody" failed.      "sbody" failed. This bug has been fixed.
235    
236  13. Added a pcredemo man page, created automatically from the pcredemo.c file,  13. The string returned by pcre_dfa_exec() after a partial match has been
237      so that the demonstration program is easily available in environments where      changed so that it starts at the first inspected character rather than the
238      PCRE has not been installed from source.      first character of the match. This makes a difference only if the pattern
239        starts with a lookbehind assertion or \b or \B (\K is not supported by
240  14. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,      pcre_dfa_exec()). It's an incompatible change, but it makes the two
241        matching functions compatible, and I think it's the right thing to do.
242    
243    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
244        so that the demonstration program is easily available in environments where
245        PCRE has not been installed from source.
246    
247    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
248      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
249      library.      library.
250    
251  15. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
252      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
253      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
254      these options useful.      these options useful.
255    
256    17. If a caller to the POSIX matching function regexec() passes a non-zero
257        value for nmatch with a NULL value for pmatch, the value of
258        nmatch is forced to zero.
259    
260    18. RunGrepTest did not have a test for the availability of the -u option of
261        the diff command, as RunTest does. It now checks in the same way as
262        RunTest, and also checks for the -b option.
263    
264    19. If an odd number of negated classes containing just a single character
265        interposed, within parentheses, between a forward reference to a named
266        subpattern and the definition of the subpattern, compilation crashed with
267        an internal error, complaining that it could not find the referenced
268        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
269        [The bug was that it was starting one character too far in when skipping
270        over the character class, thus treating the ] as data rather than
271        terminating the class. This meant it could skip too much.]
272    
273    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
274        /g option in pcretest when the pattern contains \K, which makes it possible
275        to have an empty string match not at the start, even when the pattern is
276        anchored. Updated pcretest and pcredemo to use this option.
277    
278    21. If the maximum number of capturing subpatterns in a recursion was greater
279        than the maximum at the outer level, the higher number was returned, but
280        with unset values at the outer level. The correct (outer level) value is
281        now given.
282    
283    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
284        PCRE did not set those parentheses (unlike Perl). I have now found a way to
285        make it do so. The string so far is captured, making this feature
286        compatible with Perl.
287    
288    23. The tests have been re-organized, adding tests 11 and 12, to make it
289        possible to check the Perl 5.10 features against Perl 5.10.
290    
291    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
292        pattern matches a fixed length string. PCRE did not allow this; now it
293        does. Neither allows recursion.
294    
295    25. I finally figured out how to implement a request to provide the minimum
296        length of subject string that was needed in order to match a given pattern.
297        (It was back references and recursion that I had previously got hung up
298        on.) This code has now been added to pcre_study(); it finds a lower bound
299        to the length of subject needed. It is not necessarily the greatest lower
300        bound, but using it to avoid searching strings that are too short does give
301        some useful speed-ups. The value is available to calling programs via
302        pcre_fullinfo().
303    
304    26. While implementing 25, I discovered to my embarrassment that pcretest had
305        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
306        study optimizations had never been tested with that matching function.
307        Oops. What is worse, even when it was passed study data, there was a bug in
308        pcre_dfa_exec() that meant it never actually used it. Double oops. There
309        were also very few tests of studied patterns with pcre_dfa_exec().
310    
311    27. If (?| is used to create subpatterns with duplicate numbers, they are now
312        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
313        on the other side of the coin, they are no longer allowed to have different
314        names, because these cannot be distinguished in PCRE, and this has caused
315        confusion. (This is a difference from Perl.)
316    
317    28. When duplicate subpattern names are present (necessarily with different
318        numbers, as required by 27 above), and a test is made by name in a
319        conditional pattern, either for a subpattern having been matched, or for
320        recursion in such a pattern, all the associated numbered subpatterns are
321        tested, and the overall condition is true if the condition is true for any
322        one of them. This is the way Perl works, and is also more like the way
323        testing by number works.
324    
325    
326  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
327  ---------------------  ---------------------

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