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revision 17 by nigel, Sat Feb 24 21:38:29 2007 UTC revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC
# Line 2  ChangeLog for PCRE Line 2  ChangeLog for PCRE
2  ------------------  ------------------
5    Version 2.09 14-Sep-99
6    ----------------------
8    1. Add support for the /+ modifier to perltest (to output $` like it does in
9    pcretest).
11    2. Add support for the /g modifier to perltest.
13    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
14    matches null strings.
16    4. Fix perltest so that it doesn't do unwanted things when fed an empty
17    pattern. Perl treats empty patterns specially - it reuses the most recent
18    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
19    effect.
21    5. The POSIX interface was broken in that it was just handing over the POSIX
22    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
23    required a bigger vector, with some working space on the end. This means that
24    the POSIX wrapper now has to get and free some memory, and copy the results.
27    Version 2.08 31-Aug-99
28    ----------------------
30    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
31    trying to match at the startoffset position, but instead was moving forward to
32    the next newline as if a previous match had failed.
34    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
35    and could get into a loop if a null string was matched other than at the start
36    of the subject.
38    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
39    be distinguished at compile time, and for completeness also added PCRE_DATE.
41    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
42    in GnuWin32 environments.
45    Version 2.07 29-Jul-99
46    ----------------------
48    1. The documentation is now supplied in plain text form and HTML as well as in
49    the form of man page sources.
51    2. C++ compilers don't like assigning (void *) values to other pointer types.
52    In particular this affects malloc(). Although there is no problem in Standard
53    C, I've put in casts to keep C++ compilers happy.
55    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
56    should be (const char *).
58    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
59    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
60    However, I haven't made this a standard facility. The documentation doesn't
61    mention it, and the Makefile doesn't support it.
63    5. The Makefile now contains an "install" target, with editable destinations at
64    the top of the file. The pcretest program is not installed.
66    6. pgrep -V now gives the PCRE version number and date.
68    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
69    causing the entire string to be ignored, instead of just the last character.
71    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
72    non-matching string, it can take a very, very long time, even for strings of
73    quite modest length, because of the nested recursion. PCRE now does better in
74    some of these cases. It does this by remembering the last required literal
75    character in the pattern, and pre-searching the subject to ensure it is present
76    before running the real match. In other words, it applies a heuristic to detect
77    some types of certain failure quickly, and in the above example, if presented
78    with a string that has no trailing " it gives "no match" very quickly.
80    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
81    other alternatives are tried instead.
84    Version 2.06 09-Jun-99
85    ----------------------
87    1. Change pcretest's output for amount of store used to show just the code
88    space, because the remainder (the data block) varies in size between 32-bit and
89    64-bit systems.
91    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
92    start matching at. This allows lookbehinds to work when searching for multiple
93    occurrences in a string.
95    3. Added additional options to pcretest for testing multiple occurrences:
97       /+   outputs the rest of the string that follows a match
98       /g   loops for multiple occurrences, using the new startoffset argument
99       /G   loops for multiple occurrences by passing an incremented pointer
101    4. PCRE wasn't doing the "first character" optimization for patterns starting
102    with \b or \B, though it was doing it for other lookbehind assertions. That is,
103    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
104    the letter 'x'. On long subject strings, this gives a significant speed-up.
107    Version 2.05 21-Apr-99
108    ----------------------
110    1. Changed the type of magic_number from int to long int so that it works
111    properly on 16-bit systems.
113    2. Fixed a bug which caused patterns starting with .* not to work correctly
114    when the subject string contained newline characters. PCRE was assuming
115    anchoring for such patterns in all cases, which is not correct because .* will
116    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
117    DOTALL is set at top level; otherwise it knows that patterns starting with .*
118    must be retried after every newline in the subject.
121    Version 2.04 18-Feb-99
122    ----------------------
124    1. For parenthesized subpatterns with repeats whose minimum was zero, the
125    computation of the store needed to hold the pattern was incorrect (too large).
126    If such patterns were nested a few deep, this could multiply and become a real
127    problem.
129    2. Added /M option to pcretest to show the memory requirement of a specific
130    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
132    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
133    compiled in such a way that the backtracking after subsequent failure was
134    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
135    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
138    Version 2.03 02-Feb-99
139    ----------------------
141    1. Fixed typo and small mistake in man page.
143    2. Added 4th condition (GPL supersedes if conflict) and created separate
144    LICENCE file containing the conditions.
146    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
147    Perl, that is the internal \ allows the delimiter to be included in the
148    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
149    the final delimiter, add \ to the end of the pattern (to test the error).
151    4. Added the convenience functions for extracting substrings after a successful
152    match. Updated pcretest to make it able to test these functions.
155    Version 2.02 14-Jan-99
156    ----------------------
158    1. Initialized the working variables associated with each extraction so that
159    their saving and restoring doesn't refer to uninitialized store.
161    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
162    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
163    fix the problem.
165    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
166    calls, and wasn't printing the correct value for compiling calls. Increased the
167    default value of LOOPREPEAT, and the number of significant figures in the
168    times.
170    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
172    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
173    a building problem on Windows NT with a FAT file system.
176    Version 2.01 21-Oct-98
177    ----------------------
179    1. Changed the API for pcre_compile() to allow for the provision of a pointer
180    to character tables built by pcre_maketables() in the current locale. If NULL
181    is passed, the default tables are used.
184    Version 2.00 24-Sep-98
185    ----------------------
187    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
188    it any more.
190    2. Allow quantification of (?>) groups, and make it work correctly.
192    3. The first character computation wasn't working for (?>) groups.
194    4. Correct the implementation of \Z (it is permitted to match on the \n at the
195    end of the subject) and add 5.005's \z, which really does match only at the
196    very end of the subject.
198    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
200    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
201    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
202    localized options. All options to pcre_study() were also removed.
204    7. Add other new features from 5.005:
206       $(?<=           positive lookbehind
207       $(?<!           negative lookbehind
208       (?imsx-imsx)    added the unsetting capability
209                       such a setting is global if at outer level; local otherwise
210       (?imsx-imsx:)   non-capturing groups with option setting
211       (?(cond)re|re)  conditional pattern matching
213       A backreference to itself in a repeated group matches the previous
214       captured string.
216    8. General tidying up of studying (both automatic and via "study")
217    consequential on the addition of new assertions.
219    9. As in 5.005, unlimited repeated groups that could match an empty substring
220    are no longer faulted at compile time. Instead, the loop is forcibly broken at
221    runtime if any iteration does actually match an empty substring.
223    10. Include the RunTest script in the distribution.
225    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
226    discrepancies, some of which were old and were also with respect to 5.004. They
227    have now been fixed.
230    Version 1.09 28-Apr-98
231    ----------------------
233    1. A negated single character class followed by a quantifier with a minimum
234    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
235    program crashes, or just wrong answers. This did not apply to negated classes
236    containing more than one character, or to minima other than one.
239    Version 1.08 27-Mar-98
240    ----------------------
242    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
244    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
245    latter must appear before anything that relies on it in the pattern.
248  Version 1.07 16-Feb-98  Version 1.07 16-Feb-98
249  ----------------------  ----------------------

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