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

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