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revision 19 by nigel, Sat Feb 24 21:38:33 2007 UTC revision 37 by nigel, Sat Feb 24 21:39:09 2007 UTC
# Line 2  ChangeLog for PCRE Line 2  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    
5    Version 2.07 29-Jul-99
6    ----------------------
7    
8    1. The documentation is now supplied in plain text form and HTML as well as in
9    the form of man page sources.
10    
11    2. C++ compilers don't like assigning (void *) values to other pointer types.
12    In particular this affects malloc(). Although there is no problem in Standard
13    C, I've put in casts to keep C++ compilers happy.
14    
15    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
16    should be (const char *).
17    
18    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
19    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
20    However, I haven't made this a standard facility. The documentation doesn't
21    mention it, and the Makefile doesn't support it.
22    
23    5. The Makefile now contains an "install" target, with editable destinations at
24    the top of the file. The pcretest program is not installed.
25    
26    6. pgrep -V now gives the PCRE version number and date.
27    
28    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
29    causing the entire string to be ignored, instead of just the last character.
30    
31    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
32    non-matching string, it can take a very, very long time, even for strings of
33    quite modest length, because of the nested recursion. PCRE now does better in
34    some of these cases. It does this by remembering the last required literal
35    character in the pattern, and pre-searching the subject to ensure it is present
36    before running the real match. In other words, it applies a heuristic to detect
37    some types of certain failure quickly, and in the above example, if presented
38    with a string that has no trailing " it gives "no match" very quickly.
39    
40    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
41    other alternatives are tried instead.
42    
43    
44    Version 2.06 09-Jun-99
45    ----------------------
46    
47    1. Change pcretest's output for amount of store used to show just the code
48    space, because the remainder (the data block) varies in size between 32-bit and
49    64-bit systems.
50    
51    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
52    start matching at. This allows lookbehinds to work when searching for multiple
53    occurrences in a string.
54    
55    3. Added additional options to pcretest for testing multiple occurrences:
56    
57       /+   outputs the rest of the string that follows a match
58       /g   loops for multiple occurrences, using the new startoffset argument
59       /G   loops for multiple occurrences by passing an incremented pointer
60    
61    4. PCRE wasn't doing the "first character" optimization for patterns starting
62    with \b or \B, though it was doing it for other lookbehind assertions. That is,
63    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
64    the letter 'x'. On long subject strings, this gives a significant speed-up.
65    
66    
67    Version 2.05 21-Apr-99
68    ----------------------
69    
70    1. Changed the type of magic_number from int to long int so that it works
71    properly on 16-bit systems.
72    
73    2. Fixed a bug which caused patterns starting with .* not to work correctly
74    when the subject string contained newline characters. PCRE was assuming
75    anchoring for such patterns in all cases, which is not correct because .* will
76    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
77    DOTALL is set at top level; otherwise it knows that patterns starting with .*
78    must be retried after every newline in the subject.
79    
80    
81    Version 2.04 18-Feb-99
82    ----------------------
83    
84    1. For parenthesized subpatterns with repeats whose minimum was zero, the
85    computation of the store needed to hold the pattern was incorrect (too large).
86    If such patterns were nested a few deep, this could multiply and become a real
87    problem.
88    
89    2. Added /M option to pcretest to show the memory requirement of a specific
90    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
91    
92    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
93    compiled in such a way that the backtracking after subsequent failure was
94    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
95    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
96    
97    
98    Version 2.03 02-Feb-99
99    ----------------------
100    
101    1. Fixed typo and small mistake in man page.
102    
103    2. Added 4th condition (GPL supersedes if conflict) and created separate
104    LICENCE file containing the conditions.
105    
106    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
107    Perl, that is the internal \ allows the delimiter to be included in the
108    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
109    the final delimiter, add \ to the end of the pattern (to test the error).
110    
111    4. Added the convenience functions for extracting substrings after a successful
112    match. Updated pcretest to make it able to test these functions.
113    
114    
115    Version 2.02 14-Jan-99
116    ----------------------
117    
118    1. Initialized the working variables associated with each extraction so that
119    their saving and restoring doesn't refer to uninitialized store.
120    
121    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
122    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
123    fix the problem.
124    
125    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
126    calls, and wasn't printing the correct value for compiling calls. Increased the
127    default value of LOOPREPEAT, and the number of significant figures in the
128    times.
129    
130    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
131    
132    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
133    a building problem on Windows NT with a FAT file system.
134    
135    
136    Version 2.01 21-Oct-98
137    ----------------------
138    
139    1. Changed the API for pcre_compile() to allow for the provision of a pointer
140    to character tables built by pcre_maketables() in the current locale. If NULL
141    is passed, the default tables are used.
142    
143    
144    Version 2.00 24-Sep-98
145    ----------------------
146    
147    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
148    it any more.
149    
150    2. Allow quantification of (?>) groups, and make it work correctly.
151    
152    3. The first character computation wasn't working for (?>) groups.
153    
154    4. Correct the implementation of \Z (it is permitted to match on the \n at the
155    end of the subject) and add 5.005's \z, which really does match only at the
156    very end of the subject.
157    
158    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
159    
160    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
161    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
162    localized options. All options to pcre_study() were also removed.
163    
164    7. Add other new features from 5.005:
165    
166       $(?<=           positive lookbehind
167       $(?<!           negative lookbehind
168       (?imsx-imsx)    added the unsetting capability
169                       such a setting is global if at outer level; local otherwise
170       (?imsx-imsx:)   non-capturing groups with option setting
171       (?(cond)re|re)  conditional pattern matching
172    
173       A backreference to itself in a repeated group matches the previous
174       captured string.
175    
176    8. General tidying up of studying (both automatic and via "study")
177    consequential on the addition of new assertions.
178    
179    9. As in 5.005, unlimited repeated groups that could match an empty substring
180    are no longer faulted at compile time. Instead, the loop is forcibly broken at
181    runtime if any iteration does actually match an empty substring.
182    
183    10. Include the RunTest script in the distribution.
184    
185    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
186    discrepancies, some of which were old and were also with respect to 5.004. They
187    have now been fixed.
188    
189    
190    Version 1.09 28-Apr-98
191    ----------------------
192    
193    1. A negated single character class followed by a quantifier with a minimum
194    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
195    program crashes, or just wrong answers. This did not apply to negated classes
196    containing more than one character, or to minima other than one.
197    
198    
199  Version 1.08 27-Mar-98  Version 1.08 27-Mar-98
200  ----------------------  ----------------------
201    

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