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

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