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1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 nigel 5
5 nigel 31 Version 2.04 18-Feb-99
6     ----------------------
7    
8     1. For parenthesized subpatterns with repeats whose minimum was zero, the
9     computation of the store needed to hold the pattern was incorrect (too large).
10     If such patterns were nested a few deep, this could multiply and become a real
11     problem.
12    
13     2. Added /M option to pcretest to show the memory requirement of a specific
14     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
15    
16     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
17     compiled in such a way that the backtracking after subsequent failure was
18     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
19     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
20    
21    
22 nigel 29 Version 2.03 02-Feb-99
23     ----------------------
24    
25     1. Fixed typo and small mistake in man page.
26    
27 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
28     LICENCE file containing the conditions.
29 nigel 29
30     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
31     Perl, that is the internal \ allows the delimiter to be included in the
32     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
33     the final delimiter, add \ to the end of the pattern (to test the error).
34    
35     4. Added the convenience functions for extracting substrings after a successful
36     match. Updated pcretest to make it able to test these functions.
37    
38    
39 nigel 27 Version 2.02 14-Jan-99
40     ----------------------
41    
42     1. Initialized the working variables associated with each extraction so that
43     their saving and restoring doesn't refer to uninitialized store.
44    
45     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
46     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
47     fix the problem.
48    
49     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
50     calls, and wasn't printing the correct value for compiling calls. Increased the
51     default value of LOOPREPEAT, and the number of significant figures in the
52     times.
53    
54     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
55    
56     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
57     a building problem on Windows NT with a FAT file system.
58    
59    
60 nigel 25 Version 2.01 21-Oct-98
61     ----------------------
62    
63     1. Changed the API for pcre_compile() to allow for the provision of a pointer
64     to character tables built by pcre_maketables() in the current locale. If NULL
65     is passed, the default tables are used.
66    
67    
68 nigel 23 Version 2.00 24-Sep-98
69 nigel 21 ----------------------
70    
71 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
72     it any more.
73    
74     2. Allow quantification of (?>) groups, and make it work correctly.
75    
76     3. The first character computation wasn't working for (?>) groups.
77    
78     4. Correct the implementation of \Z (it is permitted to match on the \n at the
79     end of the subject) and add 5.005's \z, which really does match only at the
80     very end of the subject.
81    
82     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
83    
84     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
85     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
86     localized options. All options to pcre_study() were also removed.
87    
88     7. Add other new features from 5.005:
89    
90     $(?<= positive lookbehind
91     $(?<! negative lookbehind
92     (?imsx-imsx) added the unsetting capability
93     such a setting is global if at outer level; local otherwise
94     (?imsx-imsx:) non-capturing groups with option setting
95     (?(cond)re|re) conditional pattern matching
96    
97     A backreference to itself in a repeated group matches the previous
98     captured string.
99    
100     8. General tidying up of studying (both automatic and via "study")
101     consequential on the addition of new assertions.
102    
103     9. As in 5.005, unlimited repeated groups that could match an empty substring
104     are no longer faulted at compile time. Instead, the loop is forcibly broken at
105     runtime if any iteration does actually match an empty substring.
106    
107     10. Include the RunTest script in the distribution.
108    
109     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
110     discrepancies, some of which were old and were also with respect to 5.004. They
111     have now been fixed.
112    
113    
114     Version 1.09 28-Apr-98
115     ----------------------
116    
117 nigel 21 1. A negated single character class followed by a quantifier with a minimum
118     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
119     program crashes, or just wrong answers. This did not apply to negated classes
120     containing more than one character, or to minima other than one.
121    
122    
123 nigel 19 Version 1.08 27-Mar-98
124     ----------------------
125    
126     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
127    
128     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
129     latter must appear before anything that relies on it in the pattern.
130    
131    
132 nigel 17 Version 1.07 16-Feb-98
133     ----------------------
134    
135     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
136     repeat of a potentially empty string).
137    
138    
139 nigel 15 Version 1.06 23-Jan-98
140     ----------------------
141    
142     1. Added Markus Oberhumer's little patches for C++.
143    
144     2. Literal strings longer than 255 characters were broken.
145    
146    
147 nigel 13 Version 1.05 23-Dec-97
148     ----------------------
149    
150     1. Negated character classes containing more than one character were failing if
151     PCRE_CASELESS was set at run time.
152    
153    
154 nigel 11 Version 1.04 19-Dec-97
155     ----------------------
156    
157     1. Corrected the man page, where some "const" qualifiers had been omitted.
158    
159     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
160     input syntax.
161    
162     3. Fixed memory leak which occurred when a regex with back references was
163     matched with an offsets vector that wasn't big enough. The temporary memory
164     that is used in this case wasn't being freed if the match failed.
165    
166     4. Tidied pcretest to ensure it frees memory that it gets.
167    
168     5. Temporary memory was being obtained in the case where the passed offsets
169     vector was exactly big enough.
170    
171     6. Corrected definition of offsetof() from change 5 below.
172    
173     7. I had screwed up change 6 below and broken the rules for the use of
174     setjmp(). Now fixed.
175    
176    
177 nigel 9 Version 1.03 18-Dec-97
178     ----------------------
179    
180     1. A erroneous regex with a missing opening parenthesis was correctly
181     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
182     on some systems.
183    
184     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
185     it was reported that one broken compiler failed on the former because "code" is
186     also an independent variable.
187    
188     3. The erroneous regex a[]b caused an array overrun reference.
189    
190     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
191     fail on data ending with that character. (It was going on too far, and checking
192     the next character, typically a binary zero.) This was specific to the
193     optimized code for single-character negative classes.
194    
195     5. Added a contributed patch from the TIN world which does the following:
196    
197     + Add an undef for memmove, in case the the system defines a macro for it.
198    
199     + Add a definition of offsetof(), in case there isn't one. (I don't know
200     the reason behind this - offsetof() is part of the ANSI standard - but
201     it does no harm).
202    
203     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
204     most of the places where whitespace preceded '#'. I have given up and
205     allowed the remaining 2 cases to be at the margin.
206    
207     + Rename some variables in pcre to eliminate shadowing. This seems very
208     pedantic, but does no harm, of course.
209    
210     6. Moved the call to setjmp() into its own function, to get rid of warnings
211     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
212    
213     7. Constructs such as \d{8,} were compiling into the equivalent of
214 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
215 nigel 9 outcome, but in this particular case used more store than had been allocated,
216     which caused the bug to be discovered because it threw up an internal error.
217    
218     8. The debugging code in both pcre and pcretest for outputting the compiled
219     form of a regex was going wrong in the case of back references followed by
220     curly-bracketed repeats.
221    
222    
223 nigel 7 Version 1.02 12-Dec-97
224     ----------------------
225    
226     1. Typos in pcre.3 and comments in the source fixed.
227    
228     2. Applied a contributed patch to get rid of places where it used to remove
229     'const' from variables, and fixed some signed/unsigned and uninitialized
230     variable warnings.
231    
232     3. Added the "runtest" target to Makefile.
233    
234     4. Set default compiler flag to -O2 rather than just -O.
235    
236    
237 nigel 5 Version 1.01 19-Nov-97
238     ----------------------
239    
240     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
241     like /([ab]*)*/, that is, for classes with more than one character in them.
242    
243     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
244     as /((?>a*))*/ (a PCRE_EXTRA facility).
245    
246    
247     Version 1.00 18-Nov-97
248     ----------------------
249    
250     1. Added compile-time macros to support systems such as SunOS4 which don't have
251     memmove() or strerror() but have other things that can be used instead.
252    
253     2. Arranged that "make clean" removes the executables.
254    
255    
256 nigel 3 Version 0.99 27-Oct-97
257     ----------------------
258    
259     1. Fixed bug in code for optimizing classes with only one character. It was
260     initializing a 32-byte map regardless, which could cause it to run off the end
261     of the memory it had got.
262    
263     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
264    
265    
266     Version 0.98 22-Oct-97
267     ----------------------
268    
269     1. Fixed bug in code for handling temporary memory usage when there are more
270     back references than supplied space in the ovector. This could cause segfaults.
271    
272    
273     Version 0.97 21-Oct-97
274     ----------------------
275    
276     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
277    
278     2. Optimized negated single characters not to use a bit map.
279    
280     3. Brought error texts together as macro definitions; clarified some of them;
281     fixed one that was wrong - it said "range out of order" when it meant "invalid
282     escape sequence".
283    
284     4. Changed some char * arguments to const char *.
285    
286     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
287    
288     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
289     pcretest.
290    
291    
292     Version 0.96 16-Oct-97
293     ----------------------
294    
295     1. Added a simple "pgrep" utility to the distribution.
296    
297     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
298     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
299     where "ddd" means "one or more decimal digits".
300    
301     3. Fixed serious bug. If a pattern had a back reference, but the call to
302     pcre_exec() didn't supply a large enough ovector to record the related
303     identifying subpattern, the match always failed. PCRE now remembers the number
304     of the largest back reference, and gets some temporary memory in which to save
305     the offsets during matching if necessary, in order to ensure that
306     backreferences always work.
307    
308     4. Increased the compatibility with Perl in a number of ways:
309    
310     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
311     to request this handling. The option can be set at compile or exec time.
312    
313     (b) $ matches before a terminating newline by default; an option
314     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
315     mode). The option can be set at compile or exec time.
316    
317     (c) The handling of \ followed by a digit other than 0 is now supposed to be
318     the same as Perl's. If the decimal number it represents is less than 10
319     or there aren't that many previous left capturing parentheses, an octal
320     escape is read. Inside a character class, it's always an octal escape,
321     even if it is a single digit.
322    
323     (d) An escaped but undefined alphabetic character is taken as a literal,
324     unless PCRE_EXTRA is set. Currently this just reserves the remaining
325     escapes.
326    
327     (e) {0} is now permitted. (The previous item is removed from the compiled
328     pattern).
329    
330     5. Changed all the names of code files so that the basic parts are no longer
331     than 10 characters, and abolished the teeny "globals.c" file.
332    
333     6. Changed the handling of character classes; they are now done with a 32-byte
334     bit map always.
335    
336     7. Added the -d and /D options to pcretest to make it possible to look at the
337     internals of compilation without having to recompile pcre.
338    
339    
340     Version 0.95 23-Sep-97
341     ----------------------
342    
343     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
344     \x20 at the start of a run of normal characters. These were being treated as
345     real characters, instead of the source characters being re-checked.
346    
347    
348     Version 0.94 18-Sep-97
349     ----------------------
350    
351     1. The functions are now thread-safe, with the caveat that the global variables
352     containing pointers to malloc() and free() or alternative functions are the
353     same for all threads.
354    
355     2. Get pcre_study() to generate a bitmap of initial characters for non-
356     anchored patterns when this is possible, and use it if passed to pcre_exec().
357    
358    
359     Version 0.93 15-Sep-97
360     ----------------------
361    
362     1. /(b)|(:+)/ was computing an incorrect first character.
363    
364     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
365     but not actually doing anything yet.
366    
367     3. Treat "-" characters in classes that cannot be part of ranges as literals,
368     as Perl does (e.g. [-az] or [az-]).
369    
370     4. Set the anchored flag if a branch starts with .* or .*? because that tests
371     all possible positions.
372    
373     5. Split up into different modules to avoid including unneeded functions in a
374     compiled binary. However, compile and exec are still in one module. The "study"
375     function is split off.
376    
377     6. The character tables are now in a separate module whose source is generated
378     by an auxiliary program - but can then be edited by hand if required. There are
379     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
380     toupper() in the code.
381    
382     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
383     make them global. Abolish the function for setting them, as the caller can now
384     set them directly.
385    
386    
387     Version 0.92 11-Sep-97
388     ----------------------
389    
390     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
391     (e.g. /a{1,3}/) was broken (I mis-optimized it).
392    
393     2. Caseless matching was not working in character classes if the characters in
394     the pattern were in upper case.
395    
396     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
397    
398     4. Make PCRE_ANCHORED public and accept as a compile option.
399    
400     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
401     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
402     pass them.
403    
404     6. Give an error if bad option bits passed at compile or run time.
405    
406     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
407     pcretest to cause it to pass that flag.
408    
409     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
410     options, and the first character, if set.
411    
412     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
413    
414    
415     Version 0.91 10-Sep-97
416     ----------------------
417    
418     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
419     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
420    
421     2. PCRE was looping on encountering an indefinitely repeated back reference to
422     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
423     Perl does - treats the match as successful.
424    
425     ****

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