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Revision 365 - (hide annotations) (download)
Fri Jul 11 17:06:55 2008 UTC (6 years, 3 months ago) by ph10
File size: 159129 byte(s)
Further fixes for bumpalong processing in UTF-8 mode.

1 nigel 3 ChangeLog for PCRE
2     ------------------
3    
4 ph10 349 Version 8.0 02 Jul-08
5     ---------------------
6    
7     1. Replaced UCP searching code with optimized version as implemented for Ad
8     Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9 ph10 351 stage table and inline lookup instead of a function, giving speed ups of 2
10     to 5 times on some simple patterns that I tested. Permission was given to
11     distribute the MultiStage2.py script that generates the tables (it's not in
12     the tarball, but is in the Subversion repository).
13 ph10 349
14 ph10 351 2. Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15     scripts.
16 ph10 358
17 ph10 353 3. Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18     a group with a zero qualifier. The result of the study could be incorrect,
19 ph10 358 or the function might crash, depending on the pattern.
20    
21     4. Caseless matching was not working for non-ASCII characters in back
22 ph10 354 references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23 ph10 358 It now works when Unicode Property Support is available.
24    
25 ph10 355 5. In pcretest, an escape such as \x{de} in the data was always generating
26     a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27     non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28 ph10 358 truncation.
29 ph10 349
30 ph10 358 6. Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
31    
32 ph10 357 7. Added two (int) casts to pcregrep when printing the difference of two
33     pointers, in case they are 64-bit values.
34 ph10 358
35     8. Added comments about Mac OS X stack usage to the pcrestack man page and to
36     test 2 if it fails.
37 ph10 359
38     9. Added PCRE_CALL_CONVENTION just before the names of all exported functions,
39     and a #define of that name to empty if it is not externally set. This is to
40     allow users of MSVC to set it if necessary.
41    
42     10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
43     the convenience functions in the pcre_get.c source file.
44 ph10 360
45     11. An option change at the start of a pattern that had top-level alternatives
46     could cause overwriting and/or a crash. This command provoked a crash in
47     some environments:
48    
49     printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
50    
51     This potential security problem was recorded as CVE-2008-2371.
52 ph10 361
53     12. For a pattern where the match had to start at the beginning or immediately
54     after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
55     pcre_dfa_exec() could read past the end of the passed subject if there was
56     no match. To help with detecting such bugs (e.g. with valgrind), I modified
57     pcretest so that it places the subject at the end of its malloc-ed buffer.
58 ph10 364
59     13. The change to pcretest in 12 above threw up a couple more cases when pcre_
60     exec() might read past the end of the data buffer in UTF-8 mode.
61    
62     14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
63     the data contained the byte 0x85 as part of a UTF-8 character within its
64 ph10 365 first line. This applied both to normal and DFA matching.
65 ph10 351
66 ph10 357
67 ph10 347 Version 7.7 07-May-08
68 ph10 321 ---------------------
69    
70     1. Applied Craig's patch to sort out a long long problem: "If we can't convert
71 ph10 345 a string to a long long, pretend we don't even have a long long." This is
72 ph10 321 done by checking for the strtoq, strtoll, and _strtoi64 functions.
73 ph10 345
74 ph10 322 2. Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
75     pre-7.6 versions, which defined a global no_arg variable instead of putting
76 ph10 332 it in the RE class. (See also #8 below.)
77 ph10 345
78     3. Remove a line of dead code, identified by coverity and reported by Nuno
79     Lopes.
80    
81 ph10 324 4. Fixed two related pcregrep bugs involving -r with --include or --exclude:
82 ph10 321
83 ph10 324 (1) The include/exclude patterns were being applied to the whole pathnames
84 ph10 345 of files, instead of just to the final components.
85    
86 ph10 324 (2) If there was more than one level of directory, the subdirectories were
87     skipped unless they satisfied the include/exclude conditions. This is
88     inconsistent with GNU grep (and could even be seen as contrary to the
89     pcregrep specification - which I improved to make it absolutely clear).
90     The action now is always to scan all levels of directory, and just
91     apply the include/exclude patterns to regular files.
92 ph10 345
93 ph10 325 5. Added the --include_dir and --exclude_dir patterns to pcregrep, and used
94 ph10 345 --exclude_dir in the tests to avoid scanning .svn directories.
95    
96 ph10 326 6. Applied Craig's patch to the QuoteMeta function so that it escapes the
97 ph10 345 NUL character as backslash + 0 rather than backslash + NUL, because PCRE
98 ph10 326 doesn't support NULs in patterns.
99 ph10 345
100     7. Added some missing "const"s to declarations of static tables in
101     pcre_compile.c and pcre_dfa_exec.c.
102    
103 ph10 328 8. Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
104 ph10 329 caused by fix #2 above. (Subsequently also a second patch to fix the
105 ph10 345 first patch. And a third patch - this was a messy problem.)
106 ph10 321
107 ph10 345 9. Applied Craig's patch to remove the use of push_back().
108    
109 ph10 332 10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
110     matching function regexec().
111 ph10 345
112     11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
113     which, however, unlike Perl's \g{...}, are subroutine calls, not back
114 ph10 333 references. PCRE supports relative numbers with this syntax (I don't think
115     Oniguruma does).
116 ph10 345
117     12. Previously, a group with a zero repeat such as (...){0} was completely
118 ph10 335 omitted from the compiled regex. However, this means that if the group
119     was called as a subroutine from elsewhere in the pattern, things went wrong
120 ph10 345 (an internal error was given). Such groups are now left in the compiled
121     pattern, with a new opcode that causes them to be skipped at execution
122 ph10 335 time.
123 ph10 345
124 ph10 341 13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
125     to the way PCRE behaves:
126 ph10 345
127 ph10 336 (a) A lone ] character is dis-allowed (Perl treats it as data).
128 ph10 345
129     (b) A back reference to an unmatched subpattern matches an empty string
130 ph10 336 (Perl fails the current match path).
131 ph10 345
132 ph10 341 (c) A data ] in a character class must be notated as \] because if the
133 ph10 345 first data character in a class is ], it defines an empty class. (In
134 ph10 341 Perl it is not possible to have an empty class.) The empty class []
135     never matches; it forces failure and is equivalent to (*FAIL) or (?!).
136     The negative empty class [^] matches any one character, independently
137     of the DOTALL setting.
138 ph10 345
139     14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
140 ph10 340 non-existent subpattern following a character class starting with ']' and
141     containing () gave an internal compiling error instead of "reference to
142     non-existent subpattern". Fortunately, when the pattern did exist, the
143 ph10 345 compiled code was correct. (When scanning forwards to check for the
144 ph10 340 existencd of the subpattern, it was treating the data ']' as terminating
145 ph10 345 the class, so got the count wrong. When actually compiling, the reference
146 ph10 340 was subsequently set up correctly.)
147 ph10 345
148 ph10 341 15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
149 ph10 345 it was being rejected as not supported by pcre_dfa_exec(), even though
150     other assertions are supported. I have made pcre_dfa_exec() support
151     (*FAIL).
152    
153 ph10 342 16. The implementation of 13c above involved the invention of a new opcode,
154 ph10 345 OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
155     cannot be changed at match time, I realized I could make a small
156     improvement to matching performance by compiling OP_ALLANY instead of
157     OP_ANY for "." when DOTALL was set, and then removing the runtime tests
158     on the OP_ANY path.
159    
160     17. Compiling pcretest on Windows with readline support failed without the
161 ph10 343 following two fixes: (1) Make the unistd.h include conditional on
162 ph10 345 HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
163    
164 ph10 344 18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
165 ph10 345 ncurses library to be included for pcretest when ReadLine support is
166     requested, but also to allow for it to be overridden. This patch came from
167     Daniel Bergström.
168 ph10 347
169 ph10 346 19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
170 ph10 347 as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
171     any errors with the current Unicode tables. Thanks to Peter Kankowski for
172     spotting this.
173 ph10 324
174 ph10 332
175 ph10 319 Version 7.6 28-Jan-08
176 ph10 300 ---------------------
177    
178 ph10 302 1. A character class containing a very large number of characters with
179     codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
180     overflow.
181 ph10 309
182     2. Patch to cut out the "long long" test in pcrecpp_unittest when
183     HAVE_LONG_LONG is not defined.
184    
185 ph10 303 3. Applied Christian Ehrlicher's patch to update the CMake build files to
186 ph10 304 bring them up to date and include new features. This patch includes:
187 ph10 309
188 ph10 304 - Fixed PH's badly added libz and libbz2 support.
189     - Fixed a problem with static linking.
190 ph10 312 - Added pcredemo. [But later removed - see 7 below.]
191 ph10 304 - Fixed dftables problem and added an option.
192     - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
193     HAVE_LONG_LONG.
194     - Added readline support for pcretest.
195 ph10 309 - Added an listing of the option settings after cmake has run.
196    
197 ph10 314 4. A user submitted a patch to Makefile that makes it easy to create
198     "pcre.dll" under mingw when using Configure/Make. I added stuff to
199     Makefile.am that cause it to include this special target, without
200     affecting anything else. Note that the same mingw target plus all
201     the other distribution libraries and programs are now supported
202     when configuring with CMake (see 6 below) instead of with
203     Configure/Make.
204 ph10 309
205 ph10 308 5. Applied Craig's patch that moves no_arg into the RE class in the C++ code.
206     This is an attempt to solve the reported problem "pcrecpp::no_arg is not
207 ph10 309 exported in the Windows port". It has not yet been confirmed that the patch
208     solves the problem, but it does no harm.
209 ph10 313
210 ph10 311 6. Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
211 ph10 319 NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
212 ph10 314 with CMake, and also correct the comment about stack recursion.
213 ph10 313
214 ph10 312 7. Remove the automatic building of pcredemo from the ./configure system and
215 ph10 313 from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
216     of a program that users should build themselves after PCRE is installed, so
217     building it automatically is not really right. What is more, it gave
218 ph10 312 trouble in some build environments.
219 ph10 300
220 ph10 319 8. Further tidies to CMakeLists.txt from Sheri and Christian.
221 ph10 308
222 ph10 319
223 ph10 298 Version 7.5 10-Jan-08
224 ph10 263 ---------------------
225    
226     1. Applied a patch from Craig: "This patch makes it possible to 'ignore'
227     values in parens when parsing an RE using the C++ wrapper."
228 ph10 286
229 ph10 264 2. Negative specials like \S did not work in character classes in UTF-8 mode.
230     Characters greater than 255 were excluded from the class instead of being
231     included.
232 ph10 286
233     3. The same bug as (2) above applied to negated POSIX classes such as
234 ph10 265 [:^space:].
235 ph10 286
236 ph10 267 4. PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
237     defined or documented. It seems to have been a typo for PCRE_STATIC, so
238 ph10 286 I have changed it.
239    
240 ph10 268 5. The construct (?&) was not diagnosed as a syntax error (it referenced the
241 ph10 286 first named subpattern) and a construct such as (?&a) would reference the
242     first named subpattern whose name started with "a" (in other words, the
243 ph10 272 length check was missing). Both these problems are fixed. "Subpattern name
244     expected" is now given for (?&) (a zero-length name), and this patch also
245     makes it give the same error for \k'' (previously it complained that that
246     was a reference to a non-existent subpattern).
247 ph10 286
248 ph10 269 6. The erroneous patterns (?+-a) and (?-+a) give different error messages;
249 ph10 286 this is right because (?- can be followed by option settings as well as by
250 ph10 269 digits. I have, however, made the messages clearer.
251 ph10 286
252 ph10 270 7. Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
253     than the number used in the conditional) now cause a compile-time error.
254     This is actually not compatible with Perl, which accepts such patterns, but
255     treats the conditional as always being FALSE (as PCRE used to), but it
256     seems to me that giving a diagnostic is better.
257 ph10 286
258 ph10 274 8. Change "alphameric" to the more common word "alphanumeric" in comments
259 ph10 275 and messages.
260 ph10 286
261     9. Fix two occurrences of "backslash" in comments that should have been
262     "backspace".
263    
264     10. Remove two redundant lines of code that can never be obeyed (their function
265     was moved elsewhere).
266    
267     11. The program that makes PCRE's Unicode character property table had a bug
268     which caused it to generate incorrect table entries for sequences of
269 ph10 277 characters that have the same character type, but are in different scripts.
270 ph10 286 It amalgamated them into a single range, with the script of the first of
271 ph10 277 them. In other words, some characters were in the wrong script. There were
272     thirteen such cases, affecting characters in the following ranges:
273 ph10 286
274 ph10 277 U+002b0 - U+002c1
275     U+0060c - U+0060d
276 ph10 286 U+0061e - U+00612
277 ph10 277 U+0064b - U+0065e
278     U+0074d - U+0076d
279     U+01800 - U+01805
280     U+01d00 - U+01d77
281     U+01d9b - U+01dbf
282     U+0200b - U+0200f
283     U+030fc - U+030fe
284     U+03260 - U+0327f
285     U+0fb46 - U+0fbb1
286     U+10450 - U+1049d
287 ph10 286
288 ph10 279 12. The -o option (show only the matching part of a line) for pcregrep was not
289     compatible with GNU grep in that, if there was more than one match in a
290     line, it showed only the first of them. It now behaves in the same way as
291     GNU grep.
292 ph10 286
293     13. If the -o and -v options were combined for pcregrep, it printed a blank
294     line for every non-matching line. GNU grep prints nothing, and pcregrep now
295     does the same. The return code can be used to tell if there were any
296     non-matching lines.
297    
298 ph10 289 14. Added --file-offsets and --line-offsets to pcregrep.
299    
300     15. The pattern (?=something)(?R) was not being diagnosed as a potentially
301 ph10 282 infinitely looping recursion. The bug was that positive lookaheads were not
302 ph10 286 being skipped when checking for a possible empty match (negative lookaheads
303     and both kinds of lookbehind were skipped).
304    
305 ph10 289 16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
306 ph10 284 inclusion of <windows.h> to before rather than after the definition of
307     INVALID_FILE_ATTRIBUTES (patch from David Byron).
308 ph10 263
309 ph10 289 17. Specifying a possessive quantifier with a specific limit for a Unicode
310 ph10 286 character property caused pcre_compile() to compile bad code, which led at
311     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
312     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
313     caused the error; without that there was no problem.
314 ph10 263
315 ph10 289 18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
316 ph10 286
317 ph10 289 19. Added --enable-pcretest-libreadline.
318 ph10 286
319 ph10 289 20. In pcrecpp.cc, the variable 'count' was incremented twice in
320 ph10 288 RE::GlobalReplace(). As a result, the number of replacements returned was
321 ph10 298 double what it should be. I removed one of the increments, but Craig sent a
322     later patch that removed the other one (the right fix) and added unit tests
323     that check the return values (which was not done before).
324 ph10 292
325 ph10 291 21. Several CMake things:
326 ph10 287
327 ph10 291 (1) Arranged that, when cmake is used on Unix, the libraries end up with
328 ph10 292 the names libpcre and libpcreposix, not just pcre and pcreposix.
329 ph10 288
330 ph10 292 (2) The above change means that pcretest and pcregrep are now correctly
331     linked with the newly-built libraries, not previously installed ones.
332 ph10 291
333 ph10 292 (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
334 ph10 298
335     22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
336     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
337     UTF-8 newline character). The key issue is that the pattern starts .*;
338     this means that the match must be either at the beginning, or after a
339     newline. The bug was in the code for advancing after a failed match and
340     checking that the new position followed a newline. It was not taking
341 ph10 294 account of UTF-8 characters correctly.
342 ph10 298
343     23. PCRE was behaving differently from Perl in the way it recognized POSIX
344     character classes. PCRE was not treating the sequence [:...:] as a
345     character class unless the ... were all letters. Perl, however, seems to
346     allow any characters between [: and :], though of course it rejects as
347     unknown any "names" that contain non-letters, because all the known class
348     names consist only of letters. Thus, Perl gives an error for [[:1234:]],
349     for example, whereas PCRE did not - it did not recognize a POSIX character
350     class. This seemed a bit dangerous, so the code has been changed to be
351     closer to Perl. The behaviour is not identical to Perl, because PCRE will
352     diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
353     treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
354     Perl does, and where it didn't before.
355    
356 ph10 296 24. Rewrite so as to remove the single use of %n from pcregrep because in some
357     Windows environments %n is disabled by default.
358 ph10 292
359    
360 ph10 260 Version 7.4 21-Sep-07
361 ph10 230 ---------------------
362    
363     1. Change 7.3/28 was implemented for classes by looking at the bitmap. This
364 ph10 231 means that a class such as [\s] counted as "explicit reference to CR or
365     LF". That isn't really right - the whole point of the change was to try to
366     help when there was an actual mention of one of the two characters. So now
367     the change happens only if \r or \n (or a literal CR or LF) character is
368 ph10 230 encountered.
369 ph10 231
370     2. The 32-bit options word was also used for 6 internal flags, but the numbers
371     of both had grown to the point where there were only 3 bits left.
372     Fortunately, there was spare space in the data structure, and so I have
373     moved the internal flags into a new 16-bit field to free up more option
374 ph10 230 bits.
375 ph10 231
376     3. The appearance of (?J) at the start of a pattern set the DUPNAMES option,
377     but did not set the internal JCHANGED flag - either of these is enough to
378     control the way the "get" function works - but the PCRE_INFO_JCHANGED
379     facility is supposed to tell if (?J) was ever used, so now (?J) at the
380 ph10 230 start sets both bits.
381    
382 ph10 231 4. Added options (at build time, compile time, exec time) to change \R from
383     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
384 ph10 230
385 ph10 243 5. doc/pcresyntax.html was missing from the distribution.
386    
387     6. Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
388 ph10 233 compatibility, even though it is no longer used.
389 ph10 243
390     7. Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
391 ph10 254 strtoull to pcrecpp.cc to select the available functions in WIN32 when the
392 ph10 259 windows.h file is present (where different names are used). [This was
393 ph10 257 reversed later after testing - see 16 below.]
394 ph10 243
395     8. Changed all #include <config.h> to #include "config.h". There were also
396 ph10 236 some further <pcre.h> cases that I changed to "pcre.h".
397 ph10 243
398 ph10 239 9. When pcregrep was used with the --colour option, it missed the line ending
399 ph10 243 sequence off the lines that it output.
400    
401     10. It was pointed out to me that arrays of string pointers cause lots of
402     relocations when a shared library is dynamically loaded. A technique of
403     using a single long string with a table of offsets can drastically reduce
404     these. I have refactored PCRE in four places to do this. The result is
405 ph10 240 dramatic:
406 ph10 243
407 ph10 240 Originally: 290
408     After changing UCP table: 187
409 ph10 243 After changing error message table: 43
410 ph10 240 After changing table of "verbs" 36
411     After changing table of Posix names 22
412 ph10 243
413 ph10 240 Thanks to the folks working on Gregex for glib for this insight.
414 ph10 247
415 ph10 244 11. --disable-stack-for-recursion caused compiling to fail unless -enable-
416 ph10 247 unicode-properties was also set.
417    
418 ph10 248 12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
419 ph10 231
420 ph10 253 13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
421     checked only for CRLF.
422 ph10 233
423 ph10 259 14. Added casts to pcretest.c to avoid compiler warnings.
424    
425 ph10 256 15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
426 ph10 253
427 ph10 257 16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
428 ph10 259 and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
429     entirely. This removes changes made in 7 above.
430 ph10 256
431 ph10 261 17. The CMake files have been updated, and there is now more information about
432     building with CMake in the NON-UNIX-USE document.
433 ph10 257
434 ph10 261
435 ph10 228 Version 7.3 28-Aug-07
436 ph10 157 ---------------------
437    
438 ph10 189 1. In the rejigging of the build system that eventually resulted in 7.1, the
439     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
440     brackets there is not right, since it causes compilers to look for an
441     installed pcre.h, not the version that is in the source that is being
442     compiled (which of course may be different). I have changed it back to:
443 ph10 197
444 ph10 189 #include "pcre.h"
445 ph10 197
446     I have a vague recollection that the change was concerned with compiling in
447     different directories, but in the new build system, that is taken care of
448     by the VPATH setting the Makefile.
449    
450 ph10 190 2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
451     when the subject happened to end in the byte 0x85 (e.g. if the last
452     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
453     characters but of course it shouldn't be taken as a newline when it is part
454     of another character. The bug was that, for an unlimited repeat of . in
455     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
456     characters when looking for a newline.
457 ph10 197
458     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
459    
460     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
461     in debug output.
462    
463 ph10 201 5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
464     long printing in the pcrecpp unittest when running under MinGW.
465 ph10 189
466 ph10 197 6. ESC_K was left out of the EBCDIC table.
467 ph10 189
468 ph10 197 7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
469     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
470     limit also applies to "virtual nesting" when a pattern is recursive, and in
471     this case 1000 isn't so big. I have been able to remove this limit at the
472     expense of backing off one optimization in certain circumstances. Normally,
473     when pcre_exec() would call its internal match() function recursively and
474     immediately return the result unconditionally, it uses a "tail recursion"
475     feature to save stack. However, when a subpattern that can match an empty
476     string has an unlimited repetition quantifier, it no longer makes this
477     optimization. That gives it a stack frame in which to save the data for
478     checking that an empty string has been matched. Previously this was taken
479     from the 1000-entry workspace that had been reserved. So now there is no
480     explicit limit, but more stack is used.
481 ph10 189
482 ph10 200 8. Applied Daniel's patches to solve problems with the import/export magic
483     syntax that is required for Windows, and which was going wrong for the
484     pcreposix and pcrecpp parts of the library. These were overlooked when this
485     problem was solved for the main library.
486 ph10 197
487 ph10 202 9. There were some crude static tests to avoid integer overflow when computing
488     the size of patterns that contain repeated groups with explicit upper
489     limits. As the maximum quantifier is 65535, the maximum group length was
490     set at 30,000 so that the product of these two numbers did not overflow a
491     32-bit integer. However, it turns out that people want to use groups that
492     are longer than 30,000 bytes (though not repeat them that many times).
493     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
494     made it possible to implement the integer overflow checks in a much more
495     dynamic way, which I have now done. The artificial limitation on group
496     length has been removed - we now have only the limit on the total length of
497     the compiled pattern, which depends on the LINK_SIZE setting.
498 ph10 208
499     10. Fixed a bug in the documentation for get/copy named substring when
500     duplicate names are permitted. If none of the named substrings are set, the
501     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
502     empty string.
503    
504     11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
505     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
506     because the ] is interpreted as the first data character and the
507     terminating ] is not found. PCRE has been made compatible with Perl in this
508     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
509     cause memory overwriting.
510    
511 ph10 206 10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
512     string has been matched (to stop an infinite loop). It was not recognizing
513 ph10 208 a conditional subpattern that could match an empty string if that
514 ph10 206 subpattern was within another subpattern. For example, it looped when
515 ph10 208 trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the
516 ph10 206 condition was not nested. This bug has been fixed.
517 ph10 208
518 ph10 207 12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
519     past the start of the subject in the presence of bytes with the top bit
520     set, for example "\x8aBCD".
521 ph10 211
522 ph10 210 13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
523     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
524 ph10 200
525 ph10 211 14. Optimized (?!) to (*FAIL).
526 ph10 202
527 ph10 212 15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
528     This restricts code points to be within the range 0 to 0x10FFFF, excluding
529     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
530     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
531     does: it's just the validity check that is more restrictive.
532 ph10 220
533     16. Inserted checks for integer overflows during escape sequence (backslash)
534     processing, and also fixed erroneous offset values for syntax errors during
535     backslash processing.
536    
537 ph10 214 17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
538 ph10 220 for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
539    
540 ph10 215 18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
541     caused an overrun.
542 ph10 220
543     19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
544     something other than just ASCII characters) inside a group that had an
545     unlimited repeat caused a loop at compile time (while checking to see
546     whether the group could match an empty string).
547    
548 ph10 217 20. Debugging a pattern containing \p or \P could cause a crash. For example,
549     [\P{Any}] did so. (Error in the code for printing property names.)
550 ph10 210
551 ph10 220 21. An orphan \E inside a character class could cause a crash.
552    
553     22. A repeated capturing bracket such as (A)? could cause a wild memory
554 ph10 218 reference during compilation.
555 ph10 220
556     23. There are several functions in pcre_compile() that scan along a compiled
557     expression for various reasons (e.g. to see if it's fixed length for look
558 ph10 218 behind). There were bugs in these functions when a repeated \p or \P was
559 ph10 220 present in the pattern. These operators have additional parameters compared
560     with \d, etc, and these were not being taken into account when moving along
561 ph10 218 the compiled data. Specifically:
562 ph10 220
563     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
564     length.
565    
566     (b) An item such as \pL+ within a repeated group could cause crashes or
567 ph10 218 loops.
568 ph10 220
569 ph10 218 (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
570 ph10 220 "reference to non-existent subpattern" error.
571    
572 ph10 221 (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
573    
574 ph10 219 24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
575 ph10 220 characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
576 ph10 211
577 ph10 222 25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
578 ph10 218
579 ph10 227 26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
580 ph10 223 character were causing crashes (broken optimization).
581 ph10 227
582 ph10 224 27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
583 ph10 227 \p or \P) caused a compile-time loop.
584    
585 ph10 226 28. More problems have arisen in unanchored patterns when CRLF is a valid line
586     break. For example, the unstudied pattern [\r\n]A does not match the string
587     "\r\nA" because change 7.0/46 below moves the current point on by two
588     characters after failing to match at the start. However, the pattern \nA
589 ph10 227 *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
590     the same is true. There doesn't seem any very clean way out of this, but
591     what I have chosen to do makes the common cases work: PCRE now takes note
592     of whether there can be an explicit match for \r or \n anywhere in the
593     pattern, and if so, 7.0/46 no longer applies. As part of this change,
594     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
595     pattern has explicit CR or LF references.
596 ph10 222
597 ph10 227 29. Added (*CR) etc for changing newline setting at start of pattern.
598 ph10 223
599 ph10 227
600 ph10 189 Version 7.2 19-Jun-07
601     ---------------------
602    
603 ph10 157 1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
604     which is apparently normally available under Windows.
605 ph10 159
606     2. Re-jig the pcregrep tests with different newline settings in an attempt
607     to make them independent of the local environment's newline setting.
608 ph10 157
609 ph10 160 3. Add code to configure.ac to remove -g from the CFLAGS default settings.
610 ph10 165
611 ph10 161 4. Some of the "internals" tests were previously cut out when the link size
612     was not 2, because the output contained actual offsets. The recent new
613 ph10 165 "Z" feature of pcretest means that these can be cut out, making the tests
614     usable with all link sizes.
615    
616 ph10 164 5. Implemented Stan Switzer's goto replacement for longjmp() when not using
617     stack recursion. This gives a massive performance boost under BSD, but just
618 ph10 165 a small improvement under Linux. However, it saves one field in the frame
619 ph10 164 in all cases.
620 ph10 172
621 ph10 166 6. Added more features from the forthcoming Perl 5.10:
622 ph10 172
623 ph10 166 (a) (?-n) (where n is a string of digits) is a relative subroutine or
624     recursion call. It refers to the nth most recently opened parentheses.
625 ph10 172
626 ph10 166 (b) (?+n) is also a relative subroutine call; it refers to the nth next
627 ph10 172 to be opened parentheses.
628    
629     (c) Conditions that refer to capturing parentheses can be specified
630 ph10 167 relatively, for example, (?(-2)... or (?(+3)...
631 ph10 172
632 ph10 168 (d) \K resets the start of the current match so that everything before
633 ph10 172 is not part of it.
634    
635 ph10 171 (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
636 ph10 172
637 ph10 171 (f) \g{name} is another synonym - part of Perl 5.10's unification of
638 ph10 172 reference syntax.
639 ph10 182
640 ph10 175 (g) (?| introduces a group in which the numbering of parentheses in each
641 ph10 182 alternative starts with the same number.
642 ph10 172
643 ph10 182 (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
644    
645 ph10 172 7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
646     PCRE_INFO_JCHANGED.
647    
648     8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not
649     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
650 ph10 170 for detecting groups that can match an empty string.
651 ph10 159
652 ph10 172 9. A pattern with a very large number of alternatives (more than several
653     hundred) was running out of internal workspace during the pre-compile
654     phase, where pcre_compile() figures out how much memory will be needed. A
655     bit of new cunning has reduced the workspace needed for groups with
656     alternatives. The 1000-alternative test pattern now uses 12 bytes of
657     workspace instead of running out of the 4096 that are available.
658 ph10 182
659 ph10 176 10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
660 ph10 172
661 ph10 179 11. Applied patch from Google to remove an optimization that didn't quite work.
662     The report of the bug said:
663 ph10 182
664 ph10 179 pcrecpp::RE("a*").FullMatch("aaa") matches, while
665     pcrecpp::RE("a*?").FullMatch("aaa") does not, and
666 ph10 182 pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
667 ph10 185
668 ph10 184 12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
669 ph10 185 it matched the wrong number of bytes.
670 ph10 172
671 ph10 179
672 ph10 155 Version 7.1 24-Apr-07
673 ph10 98 ---------------------
674    
675 ph10 111 1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
676 ph10 122 that is more "standard", making use of automake and other Autotools. There
677 ph10 99 is some re-arrangement of the files and adjustment of comments consequent
678     on this.
679 ph10 111
680     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
681     for recursive directory scanning broke on some systems because the files
682     are not scanned in any specific order and on different systems the order
683     was different. A call to "sort" has been inserted into RunGrepTest for the
684     approprate test as a short-term fix. In the longer term there may be an
685 ph10 100 alternative.
686 ph10 111
687 ph10 100 3. I had an email from Eric Raymond about problems translating some of PCRE's
688 ph10 111 man pages to HTML (despite the fact that I distribute HTML pages, some
689     people do their own conversions for various reasons). The problems
690     concerned the use of low-level troff macros .br and .in. I have therefore
691     removed all such uses from the man pages (some were redundant, some could
692 ph10 113 be replaced by .nf/.fi pairs). The 132html script that I use to generate
693     HTML has been updated to handle .nf/.fi and to complain if it encounters
694     .br or .in.
695 ph10 111
696 ph10 100 4. Updated comments in configure.ac that get placed in config.h.in and also
697 ph10 123 arranged for config.h to be included in the distribution, with the name
698 ph10 111 config.h.generic, for the benefit of those who have to compile without
699     Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
700    
701     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
702     Weber: (1) pcre_internal.h was missing some function renames; (2) updated
703 ph10 127 makevp.bat for the current PCRE, using the additional files
704 ph10 135 makevp_c.txt, makevp_l.txt, and pcregexp.pas.
705 ph10 111
706     6. A Windows user reported a minor discrepancy with test 2, which turned out
707     to be caused by a trailing space on an input line that had got lost in his
708 ph10 102 copy. The trailing space was an accident, so I've just removed it.
709 ph10 111
710 ph10 104 7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
711 ph10 111 that is needed.
712    
713 ph10 105 8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
714     as "const" (a) because they are and (b) because it helps the PHP
715     maintainers who have recently made a script to detect big data structures
716 ph10 111 in the php code that should be moved to the .rodata section. I remembered
717     to update Builducptable as well, so it won't revert if ucptable.h is ever
718 ph10 105 re-created.
719 ph10 111
720     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
721 ph10 107 pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
722 ph10 111 order to be able to cut out the UTF-8 tables in the latter when UTF-8
723     support is not required. This saves 1.5-2K of code, which is important in
724 ph10 107 some applications.
725 ph10 111
726 ph10 110 Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
727 ph10 111 so as not to refer to the tables, even though these functions will never be
728     called when UTF-8 support is disabled. Otherwise there are problems with a
729     shared library.
730    
731 ph10 118 10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
732    
733     (a) It was defining its arguments as char * instead of void *.
734    
735 ph10 123 (b) It was assuming that all moves were upwards in memory; this was true
736     a long time ago when I wrote it, but is no longer the case.
737    
738 ph10 118 The emulated memove() is provided for those environments that have neither
739 ph10 123 memmove() nor bcopy(). I didn't think anyone used it these days, but that
740 ph10 118 is clearly not the case, as these two bugs were recently reported.
741 ph10 123
742 ph10 111 11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
743 ph10 123 and Detrail to create the HTML documentation, the .txt form of the man
744     pages, and it removes trailing spaces from listed files. It also creates
745     pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
746     case, it wraps all the #defines with #ifndefs. This script should be run
747 ph10 111 before "make dist".
748 ph10 123
749 ph10 115 12. Fixed two fairly obscure bugs concerned with quantified caseless matching
750     with Unicode property support.
751 ph10 123
752     (a) For a maximizing quantifier, if the two different cases of the
753     character were of different lengths in their UTF-8 codings (there are
754     some cases like this - I found 11), and the matching function had to
755 ph10 115 back up over a mixture of the two cases, it incorrectly assumed they
756     were both the same length.
757 ph10 123
758     (b) When PCRE was configured to use the heap rather than the stack for
759     recursion during matching, it was not correctly preserving the data for
760     the other case of a UTF-8 character when checking ahead for a match
761     while processing a minimizing repeat. If the check also involved
762 ph10 115 matching a wide character, but failed, corruption could cause an
763     erroneous result when trying to check for a repeat of the original
764     character.
765 ph10 123
766 ph10 116 13. Some tidying changes to the testing mechanism:
767 ph10 98
768 ph10 116 (a) The RunTest script now detects the internal link size and whether there
769     is UTF-8 and UCP support by running ./pcretest -C instead of relying on
770 ph10 123 values substituted by "configure". (The RunGrepTest script already did
771     this for UTF-8.) The configure.ac script no longer substitutes the
772     relevant variables.
773    
774 ph10 116 (b) The debugging options /B and /D in pcretest show the compiled bytecode
775     with length and offset values. This means that the output is different
776     for different internal link sizes. Test 2 is skipped for link sizes
777     other than 2 because of this, bypassing the problem. Unfortunately,
778     there was also a test in test 3 (the locale tests) that used /B and
779 ph10 123 failed for link sizes other than 2. Rather than cut the whole test out,
780     I have added a new /Z option to pcretest that replaces the length and
781     offset values with spaces. This is now used to make test 3 independent
782 ph10 122 of link size. (Test 2 will be tidied up later.)
783 ph10 123
784     14. If erroroffset was passed as NULL to pcre_compile, it provoked a
785 ph10 122 segmentation fault instead of returning the appropriate error message.
786 ph10 134
787 ph10 131 15. In multiline mode when the newline sequence was set to "any", the pattern
788 ph10 134 ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
789     This doesn't seem right; it now treats the CRLF combination as the line
790     ending, and so does not match in that case. It's only a pattern such as ^$
791     that would hit this one: something like ^ABC$ would have failed after \r
792     and then tried again after \r\n.
793    
794 ph10 131 16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
795 ph10 134 in an attempt to make files that differ only in their line terminators
796     compare equal. This works on Linux.
797 ph10 142
798 ph10 141 17. Under certain error circumstances pcregrep might try to free random memory
799     as it exited. This is now fixed, thanks to valgrind.
800 ph10 142
801 ph10 141 19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
802 ph10 142 "abc\r\n\r\n", it found an unwanted second match after the second \r. This
803     was because its rules for how to advance for /g after matching an empty
804 ph10 143 string at the end of a line did not allow for this case. They now check for
805     it specially.
806 ph10 150
807     20. pcretest is supposed to handle patterns and data of any length, by
808     extending its buffers when necessary. It was getting this wrong when the
809 ph10 147 buffer for a data line had to be extended.
810 ph10 150
811 ph10 149 21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
812 ph10 150 CRLF as a newline sequence.
813 ph10 152
814 ph10 151 22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
815 ph10 152 out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
816     I have nevertheless tidied it up.
817 ph10 111
818 ph10 152 23. Added some casts to kill warnings from HP-UX ia64 compiler.
819 ph10 123
820 ph10 153 24. Added a man page for pcre-config.
821 ph10 152
822 ph10 153
823 nigel 93 Version 7.0 19-Dec-06
824     ---------------------
825    
826     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
827     moving to gcc 4.1.1.
828    
829     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
830     sys/time.h, which is documented as needed for this function. It doesn't
831     seem to matter on Linux, but it showed up on some releases of OS X.
832    
833     3. It seems that there are systems where bytes whose values are greater than
834     127 match isprint() in the "C" locale. The "C" locale should be the
835     default when a C program starts up. In most systems, only ASCII printing
836     characters match isprint(). This difference caused the output from pcretest
837     to vary, making some of the tests fail. I have changed pcretest so that:
838    
839     (a) When it is outputting text in the compiled version of a pattern, bytes
840     other than 32-126 are always shown as hex escapes.
841    
842     (b) When it is outputting text that is a matched part of a subject string,
843     it does the same, unless a different locale has been set for the match
844     (using the /L modifier). In this case, it uses isprint() to decide.
845    
846     4. Fixed a major bug that caused incorrect computation of the amount of memory
847     required for a compiled pattern when options that changed within the
848     pattern affected the logic of the preliminary scan that determines the
849     length. The relevant options are -x, and -i in UTF-8 mode. The result was
850     that the computed length was too small. The symptoms of this bug were
851     either the PCRE error "internal error: code overflow" from pcre_compile(),
852     or a glibc crash with a message such as "pcretest: free(): invalid next
853     size (fast)". Examples of patterns that provoked this bug (shown in
854     pcretest format) are:
855    
856     /(?-x: )/x
857     /(?x)(?-x: \s*#\s*)/
858     /((?i)[\x{c0}])/8
859     /(?i:[\x{c0}])/8
860    
861     HOWEVER: Change 17 below makes this fix obsolete as the memory computation
862     is now done differently.
863    
864     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
865     wrapper classes; (b) implement a new function in the C++ scanner that is
866     more efficient than the old way of doing things because it avoids levels of
867     recursion in the regex matching; (c) add a paragraph to the documentation
868     for the FullMatch() function.
869    
870     6. The escape sequence \n was being treated as whatever was defined as
871     "newline". Not only was this contrary to the documentation, which states
872     that \n is character 10 (hex 0A), but it also went horribly wrong when
873     "newline" was defined as CRLF. This has been fixed.
874    
875     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
876     was being set to -1 for the "end of line" case (supposedly a value that no
877     character can have). Though this value is never used (the check for end of
878     line is "zero bytes in current character"), it caused compiler complaints.
879     I've changed it to 0xffffffff.
880    
881     8. In pcre_version.c, the version string was being built by a sequence of
882     C macros that, in the event of PCRE_PRERELEASE being defined as an empty
883     string (as it is for production releases) called a macro with an empty
884     argument. The C standard says the result of this is undefined. The gcc
885     compiler treats it as an empty string (which was what was wanted) but it is
886     reported that Visual C gives an error. The source has been hacked around to
887     avoid this problem.
888    
889     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
890     builds of pcretest, and changed the call to _setmode() to use _O_BINARY
891     instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
892     of them did).
893    
894     10. Originally, pcretest opened its input and output without "b"; then I was
895     told that "b" was needed in some environments, so it was added for release
896     5.0 to both the input and output. (It makes no difference on Unix-like
897     systems.) Later I was told that it is wrong for the input on Windows. I've
898     now abstracted the modes into two macros, to make it easier to fiddle with
899     them, and removed "b" from the input mode under Windows.
900    
901     11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
902    
903     12. Added -help and --help to pcretest as an official way of being reminded
904     of the options.
905    
906     13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
907     and pcrecpp.cc because they annoy compilers at high warning levels.
908    
909     14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
910    
911     15. Fixed an occurrence of == in configure.ac that should have been = (shell
912     scripts are not C programs :-) and which was not noticed because it works
913     on Linux.
914    
915     16. pcretest is supposed to handle any length of pattern and data line (as one
916     line or as a continued sequence of lines) by extending its input buffer if
917     necessary. This feature was broken for very long pattern lines, leading to
918     a string of junk being passed to pcre_compile() if the pattern was longer
919     than about 50K.
920    
921     17. I have done a major re-factoring of the way pcre_compile() computes the
922     amount of memory needed for a compiled pattern. Previously, there was code
923     that made a preliminary scan of the pattern in order to do this. That was
924     OK when PCRE was new, but as the facilities have expanded, it has become
925     harder and harder to keep it in step with the real compile phase, and there
926     have been a number of bugs (see for example, 4 above). I have now found a
927     cunning way of running the real compile function in a "fake" mode that
928     enables it to compute how much memory it would need, while actually only
929     ever using a few hundred bytes of working memory and without too many
930     tests of the mode. This should make future maintenance and development
931     easier. A side effect of this work is that the limit of 200 on the nesting
932     depth of parentheses has been removed (though this was never a serious
933     limitation, I suspect). However, there is a downside: pcre_compile() now
934     runs more slowly than before (30% or more, depending on the pattern). I
935     hope this isn't a big issue. There is no effect on runtime performance.
936    
937     18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
938     newline (only possible for the last line of a file) and it was a
939     pattern that set a locale (followed by /Lsomething), pcretest crashed.
940    
941     19. Added additional timing features to pcretest. (1) The -tm option now times
942     matching only, not compiling. (2) Both -t and -tm can be followed, as a
943     separate command line item, by a number that specifies the number of
944     repeats to use when timing. The default is 50000; this gives better
945     precision, but takes uncomfortably long for very large patterns.
946    
947     20. Extended pcre_study() to be more clever in cases where a branch of a
948     subpattern has no definite first character. For example, (a*|b*)[cd] would
949     previously give no result from pcre_study(). Now it recognizes that the
950     first character must be a, b, c, or d.
951    
952     21. There was an incorrect error "recursive call could loop indefinitely" if
953     a subpattern (or the entire pattern) that was being tested for matching an
954     empty string contained only one non-empty item after a nested subpattern.
955     For example, the pattern (?>\x{100}*)\d(?R) provoked this error
956     incorrectly, because the \d was being skipped in the check.
957    
958     22. The pcretest program now has a new pattern option /B and a command line
959     option -b, which is equivalent to adding /B to every pattern. This causes
960     it to show the compiled bytecode, without the additional information that
961     -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
962     is the same as /B/I).
963    
964     23. A new optimization is now able automatically to treat some sequences such
965     as a*b as a*+b. More specifically, if something simple (such as a character
966     or a simple class like \d) has an unlimited quantifier, and is followed by
967     something that cannot possibly match the quantified thing, the quantifier
968     is automatically "possessified".
969    
970     24. A recursive reference to a subpattern whose number was greater than 39
971     went wrong under certain circumstances in UTF-8 mode. This bug could also
972     have affected the operation of pcre_study().
973    
974     25. Realized that a little bit of performance could be had by replacing
975     (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
976    
977     26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
978    
979     27. Possessive quantifiers such as a++ were previously implemented by turning
980     them into atomic groups such as ($>a+). Now they have their own opcodes,
981     which improves performance. This includes the automatically created ones
982     from 23 above.
983    
984     28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
985     lookahead was broken if it was not anchored. PCRE was mistakenly expecting
986     the first matched character to be a colon. This applied both to named and
987     numbered groups.
988    
989     29. The ucpinternal.h header file was missing its idempotency #ifdef.
990    
991     30. I was sent a "project" file called libpcre.a.dev which I understand makes
992     building PCRE on Windows easier, so I have included it in the distribution.
993    
994     31. There is now a check in pcretest against a ridiculously large number being
995     returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
996     loop, the loop is abandoned.
997    
998     32. Forward references to subpatterns in conditions such as (?(2)...) where
999     subpattern 2 is defined later cause pcre_compile() to search forwards in
1000     the pattern for the relevant set of parentheses. This search went wrong
1001     when there were unescaped parentheses in a character class, parentheses
1002     escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1003    
1004     33. "Subroutine" calls and backreferences were previously restricted to
1005     referencing subpatterns earlier in the regex. This restriction has now
1006     been removed.
1007    
1008     34. Added a number of extra features that are going to be in Perl 5.10. On the
1009     whole, these are just syntactic alternatives for features that PCRE had
1010     previously implemented using the Python syntax or my own invention. The
1011     other formats are all retained for compatibility.
1012    
1013     (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1014     as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1015     also .NET compatible.
1016    
1017     (b) A recursion or subroutine call to a named group can now be defined as
1018     (?&name) as well as (?P>name).
1019    
1020     (c) A backreference to a named group can now be defined as \k<name> or
1021     \k'name' as well as (?P=name). The new forms, as well as being in Perl
1022     5.10, are also .NET compatible.
1023    
1024     (d) A conditional reference to a named group can now use the syntax
1025     (?(<name>) or (?('name') as well as (?(name).
1026    
1027     (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1028     groups (named and numbered) that are never evaluated inline, but can be
1029     called as "subroutines" from elsewhere. In effect, the DEFINE condition
1030     is always false. There may be only one alternative in such a group.
1031    
1032     (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1033     as the simple (?(R). The condition is true only if the most recent
1034     recursion is that of the given number or name. It does not search out
1035     through the entire recursion stack.
1036    
1037     (g) The escape \gN or \g{N} has been added, where N is a positive or
1038     negative number, specifying an absolute or relative reference.
1039    
1040     35. Tidied to get rid of some further signed/unsigned compiler warnings and
1041     some "unreachable code" warnings.
1042    
1043     36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1044     things, this adds five new scripts.
1045    
1046     37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1047     There were also incompatibilities regarding the handling of \Q..\E inside
1048     character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1049     hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1050    
1051     38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1052     matches an empty string, and forcibly breaks the loop. There were bugs in
1053     this code in non-simple cases. For a pattern such as ^(a()*)* matched
1054     against aaaa the result was just "a" rather than "aaaa", for example. Two
1055     separate and independent bugs (that affected different cases) have been
1056     fixed.
1057    
1058     39. Refactored the code to abolish the use of different opcodes for small
1059     capturing bracket numbers. This is a tidy that I avoided doing when I
1060     removed the limit on the number of capturing brackets for 3.5 back in 2001.
1061     The new approach is not only tidier, it makes it possible to reduce the
1062     memory needed to fix the previous bug (38).
1063    
1064     40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1065     sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1066     processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1067     mode.
1068    
1069     41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1070     report.
1071    
1072     42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1073     copy construction and assignment in the C++ wrapper.
1074    
1075     43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1076     couple of bugs that could have given wrong results in the "--newline=crlf"
1077     case.
1078    
1079     44. Added a number of casts and did some reorganization of signed/unsigned int
1080     variables following suggestions from Dair Grant. Also renamed the variable
1081     "this" as "item" because it is a C++ keyword.
1082    
1083     45. Arranged for dftables to add
1084    
1085     #include "pcre_internal.h"
1086    
1087     to pcre_chartables.c because without it, gcc 4.x may remove the array
1088     definition from the final binary if PCRE is built into a static library and
1089     dead code stripping is activated.
1090    
1091     46. For an unanchored pattern, if a match attempt fails at the start of a
1092     newline sequence, and the newline setting is CRLF or ANY, and the next two
1093     characters are CRLF, advance by two characters instead of one.
1094    
1095    
1096 nigel 91 Version 6.7 04-Jul-06
1097     ---------------------
1098    
1099     1. In order to handle tests when input lines are enormously long, pcretest has
1100     been re-factored so that it automatically extends its buffers when
1101     necessary. The code is crude, but this _is_ just a test program. The
1102     default size has been increased from 32K to 50K.
1103    
1104     2. The code in pcre_study() was using the value of the re argument before
1105     testing it for NULL. (Of course, in any sensible call of the function, it
1106     won't be NULL.)
1107    
1108     3. The memmove() emulation function in pcre_internal.h, which is used on
1109     systems that lack both memmove() and bcopy() - that is, hardly ever -
1110     was missing a "static" storage class specifier.
1111    
1112     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1113     containing an extended class (one that cannot be represented by a bitmap
1114     because it contains high-valued characters or Unicode property items, e.g.
1115     [\pZ]). Almost always one would set UTF-8 mode when processing such a
1116     pattern, but PCRE should not loop if you do not (it no longer does).
1117     [Detail: two cases were found: (a) a repeated subpattern containing an
1118     extended class; (b) a recursive reference to a subpattern that followed a
1119     previous extended class. It wasn't skipping over the extended class
1120     correctly when UTF-8 mode was not set.]
1121    
1122     5. A negated single-character class was not being recognized as fixed-length
1123     in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1124     compile error "lookbehind assertion is not fixed length".
1125    
1126     6. The RunPerlTest auxiliary script was showing an unexpected difference
1127     between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1128     write a Perl script that can interpret lines of an input file either as
1129     byte characters or as UTF-8, which is what "perltest" was being required to
1130     do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1131     can't do is switch easily at run time between having the "use utf8;" pragma
1132     or not. In the end, I fudged it by using the RunPerlTest script to insert
1133     "use utf8;" explicitly for the UTF-8 tests.
1134    
1135     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1136     the end of the subject string, contrary to the documentation and to what
1137     Perl does. This was true of both matching functions. Now it matches only at
1138     the start of the subject and immediately after *internal* newlines.
1139    
1140     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1141     a pointer to an int instead of a pointer to an unsigned long int. This
1142     caused problems on 64-bit systems.
1143    
1144     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1145     instance of the 'standard' template library not being so standard".
1146    
1147     10. There was no check on the number of named subpatterns nor the maximum
1148     length of a subpattern name. The product of these values is used to compute
1149     the size of the memory block for a compiled pattern. By supplying a very
1150     long subpattern name and a large number of named subpatterns, the size
1151     computation could be caused to overflow. This is now prevented by limiting
1152     the length of names to 32 characters, and the number of named subpatterns
1153     to 10,000.
1154    
1155     11. Subpatterns that are repeated with specific counts have to be replicated in
1156     the compiled pattern. The size of memory for this was computed from the
1157     length of the subpattern and the repeat count. The latter is limited to
1158     65535, but there was no limit on the former, meaning that integer overflow
1159     could in principle occur. The compiled length of a repeated subpattern is
1160     now limited to 30,000 bytes in order to prevent this.
1161    
1162     12. Added the optional facility to have named substrings with the same name.
1163    
1164     13. Added the ability to use a named substring as a condition, using the
1165     Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1166     are numbers (not recommended). Forward references are permitted.
1167    
1168     14. Added forward references in named backreferences (if you see what I mean).
1169    
1170     15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1171     pattern could run off the end of the subject. For example, the pattern
1172     "(?s)(.{1,5})"8 did this with the subject "ab".
1173    
1174     16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1175     PCRE_CASELESS was set when matching characters that were quantified with ?
1176     or *.
1177    
1178     17. A character class other than a single negated character that had a minimum
1179     but no maximum quantifier - for example [ab]{6,} - was not handled
1180     correctly by pce_dfa_exec(). It would match only one character.
1181    
1182     18. A valid (though odd) pattern that looked like a POSIX character
1183     class but used an invalid character after [ (for example [[,abc,]]) caused
1184     pcre_compile() to give the error "Failed: internal error: code overflow" or
1185     in some cases to crash with a glibc free() error. This could even happen if
1186     the pattern terminated after [[ but there just happened to be a sequence of
1187     letters, a binary zero, and a closing ] in the memory that followed.
1188    
1189     19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1190     over the years. Originally (before any Unicode support), just the bottom 8
1191     bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1192     output from "man perlunicode" includes this:
1193    
1194     The regular expression compiler produces polymorphic opcodes. That
1195     is, the pattern adapts to the data and automatically switches to
1196     the Unicode character scheme when presented with Unicode data--or
1197     instead uses a traditional byte scheme when presented with byte
1198     data.
1199    
1200     Sadly, a wide octal escape does not cause a switch, and in a string with
1201     no other multibyte characters, these octal escapes are treated as before.
1202     Thus, in Perl, the pattern /\500/ actually matches \100 but the pattern
1203     /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1204     Unicode string.
1205    
1206     I have not perpetrated such confusion in PCRE. Up till now, it took just
1207     the bottom 8 bits, as in old Perl. I have now made octal escapes with
1208     values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1209     translate to the appropriate multibyte character.
1210    
1211     29. Applied some refactoring to reduce the number of warnings from Microsoft
1212     and Borland compilers. This has included removing the fudge introduced
1213     seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1214     a warning about an unused variable.
1215    
1216     21. PCRE has not included VT (character 0x0b) in the set of whitespace
1217     characters since release 4.0, because Perl (from release 5.004) does not.
1218     [Or at least, is documented not to: some releases seem to be in conflict
1219     with the documentation.] However, when a pattern was studied with
1220     pcre_study() and all its branches started with \s, PCRE still included VT
1221     as a possible starting character. Of course, this did no harm; it just
1222     caused an unnecessary match attempt.
1223    
1224     22. Removed a now-redundant internal flag bit that recorded the fact that case
1225     dependency changed within the pattern. This was once needed for "required
1226     byte" processing, but is no longer used. This recovers a now-scarce options
1227     bit. Also moved the least significant internal flag bit to the most-
1228     significant bit of the word, which was not previously used (hangover from
1229     the days when it was an int rather than a uint) to free up another bit for
1230     the future.
1231    
1232     23. Added support for CRLF line endings as well as CR and LF. As well as the
1233     default being selectable at build time, it can now be changed at runtime
1234     via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1235     specify that it is scanning data with non-default line endings.
1236    
1237     24. Changed the definition of CXXLINK to make it agree with the definition of
1238     LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1239    
1240     25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1241     recursions. This makes a big different to stack usage for some patterns.
1242    
1243     26. If a subpattern containing a named recursion or subroutine reference such
1244     as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1245     the space required for the compiled pattern went wrong and gave too small a
1246     value. Depending on the environment, this could lead to "Failed: internal
1247     error: code overflow at offset 49" or "glibc detected double free or
1248     corruption" errors.
1249    
1250     27. Applied patches from Google (a) to support the new newline modes and (b) to
1251     advance over multibyte UTF-8 characters in GlobalReplace.
1252    
1253     28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1254     difference for some implementation of PCRE in some Windows version.
1255    
1256     29. Added some extra testing facilities to pcretest:
1257    
1258     \q<number> in a data line sets the "match limit" value
1259     \Q<number> in a data line sets the "match recursion limt" value
1260     -S <number> sets the stack size, where <number> is in megabytes
1261    
1262     The -S option isn't available for Windows.
1263    
1264    
1265 nigel 89 Version 6.6 06-Feb-06
1266     ---------------------
1267    
1268     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1269     in pcreposix.h. I have copied the definition from pcre.h.
1270    
1271     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1272     because pcre.h is no longer a built file.
1273    
1274     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1275     not normally included in the compiled code.
1276    
1277    
1278 nigel 87 Version 6.5 01-Feb-06
1279     ---------------------
1280    
1281     1. When using the partial match feature with pcre_dfa_exec(), it was not
1282     anchoring the second and subsequent partial matches at the new starting
1283     point. This could lead to incorrect results. For example, with the pattern
1284     /1234/, partially matching against "123" and then "a4" gave a match.
1285    
1286     2. Changes to pcregrep:
1287    
1288     (a) All non-match returns from pcre_exec() were being treated as failures
1289     to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1290     error message is output. Some extra information is given for the
1291     PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1292     probably the only errors that are likely to be caused by users (by
1293     specifying a regex that has nested indefinite repeats, for instance).
1294     If there are more than 20 of these errors, pcregrep is abandoned.
1295    
1296     (b) A binary zero was treated as data while matching, but terminated the
1297     output line if it was written out. This has been fixed: binary zeroes
1298     are now no different to any other data bytes.
1299    
1300     (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1301     used to set a locale for matching. The --locale=xxxx long option has
1302     been added (no short equivalent) to specify a locale explicitly on the
1303     pcregrep command, overriding the environment variables.
1304    
1305     (d) When -B was used with -n, some line numbers in the output were one less
1306     than they should have been.
1307    
1308     (e) Added the -o (--only-matching) option.
1309    
1310     (f) If -A or -C was used with -c (count only), some lines of context were
1311     accidentally printed for the final match.
1312    
1313     (g) Added the -H (--with-filename) option.
1314    
1315     (h) The combination of options -rh failed to suppress file names for files
1316     that were found from directory arguments.
1317    
1318     (i) Added the -D (--devices) and -d (--directories) options.
1319    
1320     (j) Added the -F (--fixed-strings) option.
1321    
1322     (k) Allow "-" to be used as a file name for -f as well as for a data file.
1323    
1324     (l) Added the --colo(u)r option.
1325    
1326     (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1327     is not present by default.
1328    
1329     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1330     items such as (?R) or (?1), when the recursion could match a number of
1331     alternatives. If it matched one of the alternatives, but subsequently,
1332     outside the recursion, there was a failure, the code tried to back up into
1333     the recursion. However, because of the way PCRE is implemented, this is not
1334     possible, and the result was an incorrect result from the match.
1335    
1336     In order to prevent this happening, the specification of recursion has
1337     been changed so that all such subpatterns are automatically treated as
1338     atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1339    
1340     4. I had overlooked the fact that, in some locales, there are characters for
1341     which isalpha() is true but neither isupper() nor islower() are true. In
1342     the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1343     and ordfeminine) are like this. This affected the treatment of \w and \W
1344     when they appeared in character classes, but not when they appeared outside
1345     a character class. The bit map for "word" characters is now created
1346     separately from the results of isalnum() instead of just taking it from the
1347     upper, lower, and digit maps. (Plus the underscore character, of course.)
1348    
1349     5. The above bug also affected the handling of POSIX character classes such as
1350     [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1351     permanent tables. Instead, the bit maps for such a class were previously
1352     created as the appropriate unions of the upper, lower, and digit bitmaps.
1353     Now they are created by subtraction from the [[:word:]] class, which has
1354     its own bitmap.
1355    
1356     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1357     It is created by subtracting the vertical space characters (\x09, \x0a,
1358     \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1359     subtraction was done in the overall bitmap for a character class, meaning
1360     that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1361     be recognized. This bug has been fixed.
1362    
1363     7. Patches from the folks at Google:
1364    
1365     (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1366     real life, but is still worth protecting against".
1367    
1368     (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1369     regular expressions".
1370    
1371     (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1372     have it.
1373    
1374     (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1375     "configure" and the latter not, in order to fix a problem somebody had
1376     with compiling the Arg class on HP-UX.
1377    
1378     (e) Improve the error-handling of the C++ wrapper a little bit.
1379    
1380     (f) New tests for checking recursion limiting.
1381    
1382     8. The pcre_memmove() function, which is used only if the environment does not
1383     have a standard memmove() function (and is therefore rarely compiled),
1384     contained two bugs: (a) use of int instead of size_t, and (b) it was not
1385     returning a result (though PCRE never actually uses the result).
1386    
1387     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1388     large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1389     returned instead of calling malloc() with an overflowing number that would
1390     most likely cause subsequent chaos.
1391    
1392     10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1393    
1394     11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1395     with this option is matched, the nmatch and pmatch options of regexec() are
1396     ignored.
1397    
1398     12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1399     provided in case anyone wants to the the POSIX interface with UTF-8
1400     strings.
1401    
1402     13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1403     C++ linking (needed for some HP-UX environments).
1404    
1405     14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1406     (unused parameter) and in the pcre_printint() function (omitted "default"
1407     switch label when the default is to do nothing).
1408    
1409     15. Added some code to make it possible, when PCRE is compiled as a C++
1410     library, to replace subject pointers for pcre_exec() with a smart pointer
1411     class, thus making it possible to process discontinuous strings.
1412    
1413     16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1414     much the same function. They were added by different people who were trying
1415     to make PCRE easy to compile on non-Unix systems. It has been suggested
1416     that PCRE_EXPORT be abolished now that there is more automatic apparatus
1417     for compiling on Windows systems. I have therefore replaced it with
1418     PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1419     defaults to "extern" for C or "extern C" for C++, which works fine on
1420     Unix-like systems. It is now possible to override the value of PCRE_DATA_
1421     SCOPE with something explicit in config.h. In addition:
1422    
1423     (a) pcreposix.h still had just "extern" instead of either of these macros;
1424     I have replaced it with PCRE_DATA_SCOPE.
1425    
1426     (b) Functions such as _pcre_xclass(), which are internal to the library,
1427     but external in the C sense, all had PCRE_EXPORT in their definitions.
1428     This is apparently wrong for the Windows case, so I have removed it.
1429     (It makes no difference on Unix-like systems.)
1430    
1431     17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1432     of recursive calls to match(). This is different to MATCH_LIMIT because
1433     that limits the total number of calls to match(), not all of which increase
1434     the depth of recursion. Limiting the recursion depth limits the amount of
1435     stack (or heap if NO_RECURSE is set) that is used. The default can be set
1436     when PCRE is compiled, and changed at run time. A patch from Google adds
1437     this functionality to the C++ interface.
1438    
1439     18. Changes to the handling of Unicode character properties:
1440    
1441     (a) Updated the table to Unicode 4.1.0.
1442    
1443     (b) Recognize characters that are not in the table as "Cn" (undefined).
1444    
1445     (c) I revised the way the table is implemented to a much improved format
1446     which includes recognition of ranges. It now supports the ranges that
1447     are defined in UnicodeData.txt, and it also amalgamates other
1448     characters into ranges. This has reduced the number of entries in the
1449     table from around 16,000 to around 3,000, thus reducing its size
1450     considerably. I realized I did not need to use a tree structure after
1451     all - a binary chop search is just as efficient. Having reduced the
1452     number of entries, I extended their size from 6 bytes to 8 bytes to
1453     allow for more data.
1454    
1455     (d) Added support for Unicode script names via properties such as \p{Han}.
1456    
1457     19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1458     matching that character.
1459    
1460     20. When matching a repeated Unicode property with a minimum greater than zero,
1461     (for example \pL{2,}), PCRE could look past the end of the subject if it
1462     reached it while seeking the minimum number of characters. This could
1463     happen only if some of the characters were more than one byte long, because
1464     there is a check for at least the minimum number of bytes.
1465    
1466     21. Refactored the implementation of \p and \P so as to be more general, to
1467     allow for more different types of property in future. This has changed the
1468     compiled form incompatibly. Anybody with saved compiled patterns that use
1469     \p or \P will have to recompile them.
1470    
1471     22. Added "Any" and "L&" to the supported property types.
1472    
1473     23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1474     but give a compile time error if the value is greater than 0xff.
1475    
1476     24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1477     accidentally not being installed or uninstalled.
1478    
1479     25. The pcre.h file was built from pcre.h.in, but the only changes that were
1480     made were to insert the current release number. This seemed silly, because
1481     it made things harder for people building PCRE on systems that don't run
1482     "configure". I have turned pcre.h into a distributed file, no longer built
1483     by "configure", with the version identification directly included. There is
1484     no longer a pcre.h.in file.
1485    
1486     However, this change necessitated a change to the pcre-config script as
1487     well. It is built from pcre-config.in, and one of the substitutions was the
1488     release number. I have updated configure.ac so that ./configure now finds
1489     the release number by grepping pcre.h.
1490    
1491     26. Added the ability to run the tests under valgrind.
1492    
1493    
1494 nigel 85 Version 6.4 05-Sep-05
1495     ---------------------
1496    
1497     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1498     "--" to be printed when multiple files were scanned, even when none of the
1499     -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1500     consider it to be a bug, and have restored the previous behaviour.
1501    
1502     2. A couple of code tidies to get rid of compiler warnings.
1503    
1504     3. The pcretest program used to cheat by referring to symbols in the library
1505     whose names begin with _pcre_. These are internal symbols that are not
1506     really supposed to be visible externally, and in some environments it is
1507     possible to suppress them. The cheating is now confined to including
1508     certain files from the library's source, which is a bit cleaner.
1509    
1510     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1511     file's purpose clearer.
1512    
1513     5. Reorganized pcre_ucp_findchar().
1514    
1515    
1516 nigel 83 Version 6.3 15-Aug-05
1517     ---------------------
1518    
1519     1. The file libpcre.pc.in did not have general read permission in the tarball.
1520    
1521     2. There were some problems when building without C++ support:
1522    
1523     (a) If C++ support was not built, "make install" and "make test" still
1524     tried to test it.
1525    
1526     (b) There were problems when the value of CXX was explicitly set. Some
1527     changes have been made to try to fix these, and ...
1528    
1529     (c) --disable-cpp can now be used to explicitly disable C++ support.
1530    
1531     (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1532     backslash in a target when C++ was disabled. This confuses some
1533     versions of "make", apparently. Using an intermediate variable solves
1534     this. (Same for CPP_LOBJ.)
1535    
1536     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1537     (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1538     necessary on certain architectures.
1539    
1540     4. Added a setting of -export-symbols-regex to the link command to remove
1541     those symbols that are exported in the C sense, but actually are local
1542     within the library, and not documented. Their names all begin with
1543     "_pcre_". This is not a perfect job, because (a) we have to except some
1544     symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1545     available (and never for static libraries). I have made a note to try to
1546     find a way round (a) in the future.
1547    
1548    
1549 nigel 81 Version 6.2 01-Aug-05
1550     ---------------------
1551    
1552     1. There was no test for integer overflow of quantifier values. A construction
1553     such as {1111111111111111} would give undefined results. What is worse, if
1554     a minimum quantifier for a parenthesized subpattern overflowed and became
1555     negative, the calculation of the memory size went wrong. This could have
1556     led to memory overwriting.
1557    
1558     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1559    
1560     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1561     operating environments where this matters.
1562    
1563     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1564     PCRE options from within the C++ wrapper.
1565    
1566     5. Named capturing subpatterns were not being correctly counted when a pattern
1567     was compiled. This caused two problems: (a) If there were more than 100
1568     such subpatterns, the calculation of the memory needed for the whole
1569     compiled pattern went wrong, leading to an overflow error. (b) Numerical
1570     back references of the form \12, where the number was greater than 9, were
1571     not recognized as back references, even though there were sufficient
1572     previous subpatterns.
1573    
1574     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1575     versions of gcc, e.g. 2.95.4.
1576    
1577    
1578 nigel 79 Version 6.1 21-Jun-05
1579     ---------------------
1580    
1581     1. There was one reference to the variable "posix" in pcretest.c that was not
1582     surrounded by "#if !defined NOPOSIX".
1583    
1584     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1585     the cross-check on the old pcre_info() function, for the benefit of the
1586     cut-down version of PCRE that is currently imported into Exim.
1587    
1588     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1589     allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1590     patterns that start (?i) but I don't think that matters. The use of (?i) is
1591     just an example; this all applies to the other options as well.
1592    
1593     4. Since libtool seems to echo the compile commands it is issuing, the output
1594     from "make" can be reduced a bit by putting "@" in front of each libtool
1595     compile command.
1596    
1597     5. Patch from the folks at Google for configure.in to be a bit more thorough
1598     in checking for a suitable C++ installation before trying to compile the
1599     C++ stuff. This should fix a reported problem when a compiler was present,
1600     but no suitable headers.
1601    
1602     6. The man pages all had just "PCRE" as their title. I have changed them to
1603     be the relevant file name. I have also arranged that these names are
1604     retained in the file doc/pcre.txt, which is a concatenation in text format
1605     of all the man pages except the little individual ones for each function.
1606    
1607     7. The NON-UNIX-USE file had not been updated for the different set of source
1608     files that come with release 6. I also added a few comments about the C++
1609     wrapper.
1610    
1611    
1612 nigel 77 Version 6.0 07-Jun-05
1613     ---------------------
1614    
1615     1. Some minor internal re-organization to help with my DFA experiments.
1616    
1617     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1618     didn't matter for the library itself when fully configured, but did matter
1619     when compiling without UCP support, or within Exim, where the ucp files are
1620     not imported.
1621    
1622     3. Refactoring of the library code to split up the various functions into
1623     different source modules. The addition of the new DFA matching code (see
1624     below) to a single monolithic source would have made it really too
1625     unwieldy, quite apart from causing all the code to be include in a
1626     statically linked application, when only some functions are used. This is
1627     relevant even without the DFA addition now that patterns can be compiled in
1628     one application and matched in another.
1629    
1630     The downside of splitting up is that there have to be some external
1631     functions and data tables that are used internally in different modules of
1632     the library but which are not part of the API. These have all had their
1633     names changed to start with "_pcre_" so that they are unlikely to clash
1634     with other external names.
1635    
1636     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1637     a different (DFA) algorithm. Although it is slower than the original
1638     function, it does have some advantages for certain types of matching
1639     problem.
1640    
1641     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1642     including restarting after a partial match.
1643    
1644     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1645     defined when compiling for Windows was sent to me. I have put it into the
1646     code, though I have no means of testing or verifying it.
1647    
1648     7. Added the pcre_refcount() auxiliary function.
1649    
1650     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1651     match before or at the first newline in the subject string. In pcretest,
1652     the /f option on a pattern can be used to set this.
1653    
1654     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1655     would behave wrongly. This has been present in PCRE since release 4.0.
1656    
1657     10. A number of changes to the pcregrep command:
1658    
1659     (a) Refactored how -x works; insert ^(...)$ instead of setting
1660     PCRE_ANCHORED and checking the length, in preparation for adding
1661     something similar for -w.
1662    
1663     (b) Added the -w (match as a word) option.
1664    
1665     (c) Refactored the way lines are read and buffered so as to have more
1666     than one at a time available.
1667    
1668     (d) Implemented a pcregrep test script.
1669    
1670     (e) Added the -M (multiline match) option. This allows patterns to match
1671     over several lines of the subject. The buffering ensures that at least
1672     8K, or the rest of the document (whichever is the shorter) is available
1673     for matching (and similarly the previous 8K for lookbehind assertions).
1674    
1675     (f) Changed the --help output so that it now says
1676    
1677     -w, --word-regex(p)
1678    
1679     instead of two lines, one with "regex" and the other with "regexp"
1680     because that confused at least one person since the short forms are the
1681     same. (This required a bit of code, as the output is generated
1682     automatically from a table. It wasn't just a text change.)
1683    
1684     (g) -- can be used to terminate pcregrep options if the next thing isn't an
1685     option but starts with a hyphen. Could be a pattern or a path name
1686     starting with a hyphen, for instance.
1687    
1688     (h) "-" can be given as a file name to represent stdin.
1689    
1690     (i) When file names are being printed, "(standard input)" is used for
1691     the standard input, for compatibility with GNU grep. Previously
1692     "<stdin>" was used.
1693    
1694     (j) The option --label=xxx can be used to supply a name to be used for
1695     stdin when file names are being printed. There is no short form.
1696    
1697     (k) Re-factored the options decoding logic because we are going to add
1698     two more options that take data. Such options can now be given in four
1699     different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1700    
1701     (l) Added the -A, -B, and -C options for requesting that lines of context
1702     around matches be printed.
1703    
1704     (m) Added the -L option to print the names of files that do not contain
1705     any matching lines, that is, the complement of -l.
1706    
1707     (n) The return code is 2 if any file cannot be opened, but pcregrep does
1708     continue to scan other files.
1709    
1710     (o) The -s option was incorrectly implemented. For compatibility with other
1711     greps, it now suppresses the error message for a non-existent or non-
1712     accessible file (but not the return code). There is a new option called
1713     -q that suppresses the output of matching lines, which was what -s was
1714     previously doing.
1715    
1716     (p) Added --include and --exclude options to specify files for inclusion
1717     and exclusion when recursing.
1718    
1719     11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1720     Hopefully, it now does.
1721    
1722     12. Missing cast in pcre_study().
1723    
1724     13. Added an "uninstall" target to the makefile.
1725    
1726     14. Replaced "extern" in the function prototypes in Makefile.in with
1727     "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1728     world, but is set differently for Windows.
1729    
1730     15. Added a second compiling function called pcre_compile2(). The only
1731     difference is that it has an extra argument, which is a pointer to an
1732     integer error code. When there is a compile-time failure, this is set
1733     non-zero, in addition to the error test pointer being set to point to an
1734     error message. The new argument may be NULL if no error number is required
1735     (but then you may as well call pcre_compile(), which is now just a
1736     wrapper). This facility is provided because some applications need a
1737     numeric error indication, but it has also enabled me to tidy up the way
1738     compile-time errors are handled in the POSIX wrapper.
1739    
1740     16. Added VPATH=.libs to the makefile; this should help when building with one
1741     prefix path and installing with another. (Or so I'm told by someone who
1742     knows more about this stuff than I do.)
1743    
1744     17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1745     passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1746     match everything, including newlines. This is not POSIX-compatible, but
1747     somebody wanted the feature. From pcretest it can be activated by using
1748     both the P and the s flags.
1749    
1750     18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1751    
1752     19. libpcre.pc was being incorrectly installed as executable.
1753    
1754     20. A couple of places in pcretest check for end-of-line by looking for '\n';
1755     it now also looks for '\r' so that it will work unmodified on Windows.
1756    
1757     21. Added Google's contributed C++ wrapper to the distribution.
1758    
1759     22. Added some untidy missing memory free() calls in pcretest, to keep
1760     Electric Fence happy when testing.
1761    
1762    
1763    
1764 nigel 75 Version 5.0 13-Sep-04
1765     ---------------------
1766    
1767     1. Internal change: literal characters are no longer packed up into items
1768     containing multiple characters in a single byte-string. Each character
1769     is now matched using a separate opcode. However, there may be more than one
1770     byte in the character in UTF-8 mode.
1771    
1772     2. The pcre_callout_block structure has two new fields: pattern_position and
1773     next_item_length. These contain the offset in the pattern to the next match
1774     item, and its length, respectively.
1775    
1776     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1777     insertion of callouts before each pattern item. Added the /C option to
1778     pcretest to make use of this.
1779    
1780     4. On the advice of a Windows user, the lines
1781    
1782     #if defined(_WIN32) || defined(WIN32)
1783     _setmode( _fileno( stdout ), 0x8000 );
1784     #endif /* defined(_WIN32) || defined(WIN32) */
1785    
1786     have been added to the source of pcretest. This apparently does useful
1787     magic in relation to line terminators.
1788    
1789     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1790     for the benefit of those environments where the "b" makes a difference.
1791    
1792     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1793     to know about it. I have put a hack into configure.in that adds in code
1794     to set GCC=yes if CC=icc. This seems to end up at a point in the
1795     generated configure script that is early enough to affect the setting of
1796     compiler options, which is what is needed, but I have no means of testing
1797     whether it really works. (The user who reported this had patched the
1798     generated configure script, which of course I cannot do.)
1799    
1800     LATER: After change 22 below (new libtool files), the configure script
1801     seems to know about icc (and also ecc). Therefore, I have commented out
1802     this hack in configure.in.
1803    
1804     7. Added support for pkg-config (2 patches were sent in).
1805    
1806     8. Negated POSIX character classes that used a combination of internal tables
1807     were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1808     [[:^ascii]]. Typically, they would match almost any characters. The other
1809     POSIX classes were not broken in this way.
1810    
1811     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1812     to find the match, as PCRE was deluded into thinking that the match had to
1813     start at the start point or following a newline. The same bug applied to
1814     patterns with negative forward assertions or any backward assertions
1815     preceding ".*" at the start, unless the pattern required a fixed first
1816     character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1817    
1818     10. In UTF-8 mode, when moving forwards in the subject after a failed match
1819     starting at the last subject character, bytes beyond the end of the subject
1820     string were read.
1821    
1822     11. Renamed the variable "class" as "classbits" to make life easier for C++
1823     users. (Previously there was a macro definition, but it apparently wasn't
1824     enough.)
1825    
1826     12. Added the new field "tables" to the extra data so that tables can be passed
1827     in at exec time, or the internal tables can be re-selected. This allows
1828     a compiled regex to be saved and re-used at a later time by a different
1829     program that might have everything at different addresses.
1830    
1831     13. Modified the pcre-config script so that, when run on Solaris, it shows a
1832     -R library as well as a -L library.
1833    
1834     14. The debugging options of pcretest (-d on the command line or D on a
1835     pattern) showed incorrect output for anything following an extended class
1836     that contained multibyte characters and which was followed by a quantifier.
1837    
1838     15. Added optional support for general category Unicode character properties
1839     via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1840     support. It adds about 90K to the size of the library. The meanings of the
1841     inbuilt class escapes such as \d and \s have NOT been changed.
1842    
1843     16. Updated pcredemo.c to include calls to free() to release the memory for the
1844     compiled pattern.
1845    
1846     17. The generated file chartables.c was being created in the source directory
1847     instead of in the building directory. This caused the build to fail if the
1848     source directory was different from the building directory, and was
1849     read-only.
1850    
1851     18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1852     file. No doubt somebody will tell me if they don't make sense... Also added
1853     Dan Mooney's comments about building on OpenVMS.
1854    
1855     19. Added support for partial matching via the PCRE_PARTIAL option for
1856     pcre_exec() and the \P data escape in pcretest.
1857    
1858     20. Extended pcretest with 3 new pattern features:
1859    
1860     (i) A pattern option of the form ">rest-of-line" causes pcretest to
1861     write the compiled pattern to the file whose name is "rest-of-line".
1862     This is a straight binary dump of the data, with the saved pointer to
1863     the character tables forced to be NULL. The study data, if any, is
1864     written too. After writing, pcretest reads a new pattern.
1865    
1866     (ii) If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1867     compiled pattern from the given file. There must not be any
1868     occurrences of "<" in the file name (pretty unlikely); if there are,
1869     pcretest will instead treat the initial "<" as a pattern delimiter.
1870     After reading in the pattern, pcretest goes on to read data lines as
1871     usual.
1872    
1873     (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1874     and 16-bit fields in a compiled pattern, to simulate a pattern that
1875     was compiled on a host of opposite endianness.
1876    
1877     21. The pcre-exec() function can now cope with patterns that were compiled on
1878     hosts of opposite endianness, with this restriction:
1879    
1880     As for any compiled expression that is saved and used later, the tables
1881     pointer field cannot be preserved; the extra_data field in the arguments
1882     to pcre_exec() should be used to pass in a tables address if a value
1883     other than the default internal tables were used at compile time.
1884    
1885     22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1886     now diagnosed as an error. Previously, most of the time, a negative number
1887     would have been treated as zero, but if in addition "ovector" was passed as
1888     NULL, a crash could occur.
1889    
1890     23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1891     new versions from the libtool 1.5 distribution (the last one is a copy of
1892     a file called libtool.m4). This seems to have fixed the need to patch
1893     "configure" to support Darwin 1.3 (which I used to do). However, I still
1894     had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1895     workstation).
1896    
1897     24. Changed the PCRE licence to be the more standard "BSD" licence.
1898    
1899    
1900 nigel 73 Version 4.5 01-Dec-03
1901     ---------------------
1902    
1903     1. There has been some re-arrangement of the code for the match() function so
1904     that it can be compiled in a version that does not call itself recursively.
1905     Instead, it keeps those local variables that need separate instances for
1906     each "recursion" in a frame on the heap, and gets/frees frames whenever it
1907     needs to "recurse". Keeping track of where control must go is done by means
1908     of setjmp/longjmp. The whole thing is implemented by a set of macros that
1909     hide most of the details from the main code, and operates only if
1910     NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1911     "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1912     operating.
1913    
1914     To make it easier for callers to provide specially tailored get/free
1915     functions for this usage, two new functions, pcre_stack_malloc, and
1916     pcre_stack_free, are used. They are always called in strict stacking order,
1917     and the size of block requested is always the same.
1918    
1919     The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1920     PCRE has been compiled to use the stack or the heap for recursion. The
1921     -C option of pcretest uses this to show which version is compiled.
1922    
1923     A new data escape \S, is added to pcretest; it causes the amounts of store
1924     obtained and freed by both kinds of malloc/free at match time to be added
1925     to the output.
1926    
1927     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1928     what's available on my current Linux desktop machine.
1929    
1930     3. When matching a UTF-8 string, the test for a valid string at the start has
1931     been extended. If start_offset is not zero, PCRE now checks that it points
1932     to a byte that is the start of a UTF-8 character. If not, it returns
1933     PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1934     this is necessary because there may be backward assertions in the pattern.
1935     When matching the same subject several times, it may save resources to use
1936     PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1937    
1938     4. The code for checking the validity of UTF-8 strings has been tightened so
1939     that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1940     containing "overlong sequences".
1941    
1942     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1943     I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1944     should have been "&", but it just so happened that all the cases this let
1945     through by mistake were picked up later in the function.
1946    
1947     6. I had used a variable called "isblank" - this is a C99 function, causing
1948     some compilers to warn. To avoid this, I renamed it (as "blankclass").
1949    
1950     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1951     prompting; (b) run "./pcretest /dev/null" at the start of the test script
1952     so the version is shown; (c) stop "make test" echoing "./RunTest".
1953    
1954     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1955    
1956     9. The prototype for memmove() for systems that don't have it was using
1957     size_t, but the inclusion of the header that defines size_t was later. I've
1958     moved the #includes for the C headers earlier to avoid this.
1959    
1960     10. Added some adjustments to the code to make it easier to compiler on certain
1961     special systems:
1962    
1963     (a) Some "const" qualifiers were missing.
1964     (b) Added the macro EXPORT before all exported functions; by default this
1965     is defined to be empty.
1966     (c) Changed the dftables auxiliary program (that builds chartables.c) so
1967     that it reads its output file name as an argument instead of writing
1968     to the standard output and assuming this can be redirected.
1969    
1970     11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1971     class containing characters with values greater than 255, PCRE compilation
1972     went into a loop.
1973    
1974     12. A recursive reference to a subpattern that was within another subpattern
1975     that had a minimum quantifier of zero caused PCRE to crash. For example,
1976     (x(y(?2))z)? provoked this bug with a subject that got as far as the
1977     recursion. If the recursively-called subpattern itself had a zero repeat,
1978     that was OK.
1979    
1980     13. In pcretest, the buffer for reading a data line was set at 30K, but the
1981     buffer into which it was copied (for escape processing) was still set at
1982     1024, so long lines caused crashes.
1983    
1984     14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1985     "internal error: code overflow...". This applied to any character class
1986     that was followed by a possessive quantifier.
1987    
1988     15. Modified the Makefile to add libpcre.la as a prerequisite for
1989     libpcreposix.la because I was told this is needed for a parallel build to
1990     work.
1991    
1992     16. If a pattern that contained .* following optional items at the start was
1993     studied, the wrong optimizing data was generated, leading to matching
1994     errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1995     matching string must start with a or b or c. The correct conclusion for
1996     this pattern is that a match can start with any character.
1997    
1998    
1999 nigel 71 Version 4.4 13-Aug-03
2000     ---------------------
2001    
2002     1. In UTF-8 mode, a character class containing characters with values between
2003     127 and 255 was not handled correctly if the compiled pattern was studied.
2004     In fixing this, I have also improved the studying algorithm for such
2005     classes (slightly).
2006    
2007     2. Three internal functions had redundant arguments passed to them. Removal
2008     might give a very teeny performance improvement.
2009    
2010     3. Documentation bug: the value of the capture_top field in a callout is *one
2011     more than* the number of the hightest numbered captured substring.
2012    
2013     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2014     in incorrectly linking with a previously installed version. They now link
2015     explicitly with libpcre.la.
2016    
2017     5. configure.in no longer needs to recognize Cygwin specially.
2018    
2019     6. A problem in pcre.in for Windows platforms is fixed.
2020    
2021     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2022     pcretest, it used to include the size of the study block as part of its
2023     output. Unfortunately, the structure contains a field that has a different
2024     size on different hardware architectures. This meant that the tests that
2025     showed this size failed. As the block is currently always of a fixed size,
2026     this information isn't actually particularly useful in pcretest output, so
2027     I have just removed it.
2028    
2029     8. Three pre-processor statements accidentally did not start in column 1.
2030     Sadly, there are *still* compilers around that complain, even though
2031     standard C has not required this for well over a decade. Sigh.
2032    
2033     9. In pcretest, the code for checking callouts passed small integers in the
2034     callout_data field, which is a void * field. However, some picky compilers
2035     complained about the casts involved for this on 64-bit systems. Now
2036     pcretest passes the address of the small integer instead, which should get
2037     rid of the warnings.
2038    
2039     10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2040     both compile and run time, and gives an error if an invalid UTF-8 sequence
2041     is found. There is a option for disabling this check in cases where the
2042     string is known to be correct and/or the maximum performance is wanted.
2043    
2044     11. In response to a bug report, I changed one line in Makefile.in from
2045    
2046     -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2047     to
2048     -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2049    
2050     to look similar to other lines, but I have no way of telling whether this
2051     is the right thing to do, as I do not use Windows. No doubt I'll get told
2052     if it's wrong...
2053    
2054    
2055 nigel 69 Version 4.3 21-May-03
2056     ---------------------
2057    
2058     1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2059     Makefile.
2060    
2061     2. Some refactoring to improve the quality of the code:
2062    
2063     (i) The utf8_table... variables are now declared "const".
2064    
2065     (ii) The code for \cx, which used the "case flipping" table to upper case
2066     lower case letters, now just substracts 32. This is ASCII-specific,
2067     but the whole concept of \cx is ASCII-specific, so it seems
2068     reasonable.
2069    
2070     (iii) PCRE was using its character types table to recognize decimal and
2071     hexadecimal digits in the pattern. This is silly, because it handles
2072     only 0-9, a-f, and A-F, but the character types table is locale-
2073     specific, which means strange things might happen. A private
2074     table is now used for this - though it costs 256 bytes, a table is
2075     much faster than multiple explicit tests. Of course, the standard
2076     character types table is still used for matching digits in subject
2077     strings against \d.
2078    
2079     (iv) Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2080     ending in _t are). So I've renamed it as ESC_tee.
2081    
2082     3. The first argument for regexec() in the POSIX wrapper should have been
2083     defined as "const".
2084    
2085     4. Changed pcretest to use malloc() for its buffers so that they can be
2086     Electric Fenced for debugging.
2087    
2088     5. There were several places in the code where, in UTF-8 mode, PCRE would try
2089     to read one or more bytes before the start of the subject string. Often this
2090     had no effect on PCRE's behaviour, but in some circumstances it could
2091     provoke a segmentation fault.
2092    
2093     6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2094     to try to read one or more bytes before the start of the subject string.
2095    
2096     7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2097     UTF-8 support could misbehave in various ways if the subject string
2098     contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2099     area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2100     back over UTF-8 characters.)
2101    
2102    
2103 nigel 67 Version 4.2 14-Apr-03
2104     ---------------------
2105    
2106     1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2107    
2108     2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2109     [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2110     [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2111     [WIN_PREFIX]: new variable, "cyg" for Cygwin
2112     * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2113     and BUILD_EXEEXT
2114     Note: automatic setting of the BUILD variables is not yet working
2115     set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2116     compile-time but not at link-time
2117     [LINK]: use for linking executables only
2118     make different versions for Windows and non-Windows
2119     [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2120     libraries
2121     [LINK_FOR_BUILD]: new variable
2122     [OBJEXT]: use throughout
2123     [EXEEXT]: use throughout
2124     <winshared>: new target
2125     <wininstall>: new target
2126     <dftables.o>: use native compiler
2127     <dftables>: use native linker
2128     <install>: handle Windows platform correctly
2129     <clean>: ditto
2130     <check>: ditto
2131     copy DLL to top builddir before testing
2132    
2133     As part of these changes, -no-undefined was removed again. This was reported
2134     to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2135     in any case.
2136    
2137     3. Some tidies to get rid of compiler warnings:
2138    
2139     . In the match_data structure, match_limit was an unsigned long int, whereas
2140     match_call_count was an int. I've made them both unsigned long ints.
2141    
2142     . In pcretest the fact that a const uschar * doesn't automatically cast to
2143     a void * provoked a warning.
2144    
2145     . Turning on some more compiler warnings threw up some "shadow" variables
2146     and a few more missing casts.
2147    
2148     4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2149     option, a class that contained a single character with a value between 128
2150     and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2151    
2152     5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2153     option, a class that contained several characters, but with at least one
2154     whose value was between 128 and 255 caused PCRE to crash.
2155    
2156    
2157 nigel 65 Version 4.1 12-Mar-03
2158     ---------------------
2159 nigel 63
2160 nigel 65 1. Compiling with gcc -pedantic found a couple of places where casts were
2161     needed, and a string in dftables.c that was longer than standard compilers are
2162     required to support.
2163    
2164     2. Compiling with Sun's compiler found a few more places where the code could
2165     be tidied up in order to avoid warnings.
2166    
2167     3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2168     first of these names is deprecated in the latest Autoconf in favour of the name
2169     CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2170     compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2171     analogy I have changed it to CFLAGS_FOR_BUILD.
2172    
2173     4. Added -no-undefined to the linking command in the Makefile, because this is
2174     apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2175     linking step for the pcreposix library.
2176    
2177     5. PCRE was failing to diagnose the case of two named groups with the same
2178     name.
2179    
2180     6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2181     literal character that is needed in the subject for a match, and scans along to
2182     ensure that it is present before embarking on the full matching process. This
2183     saves time in cases of nested unlimited repeats that are never going to match.
2184     Problem: the scan can take a lot of time if the subject is very long (e.g.
2185     megabytes), thus penalizing straightforward matches. It is now done only if the
2186     amount of subject to be scanned is less than 1000 bytes.
2187    
2188     7. A lesser problem with the same optimization is that it was recording the
2189     first character of an anchored pattern as "needed", thus provoking a search
2190     right along the subject, even when the first match of the pattern was going to
2191     fail. The "needed" character is now not set for anchored patterns, unless it
2192     follows something in the pattern that is of non-fixed length. Thus, it still
2193     fulfils its original purpose of finding quick non-matches in cases of nested
2194     unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2195    
2196    
2197     Version 4.0 17-Feb-03
2198     ---------------------
2199    
2200 nigel 63 1. If a comment in an extended regex that started immediately after a meta-item
2201     extended to the end of string, PCRE compiled incorrect data. This could lead to
2202     all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2203    
2204     2. Moved to autoconf 2.53 and libtool 1.4.2.
2205    
2206     3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2207     the special perltest8 script is no longer needed - all the tests can be run
2208     from a single perltest script.
2209    
2210     4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2211     by \s. It has now been removed in PCRE. This means it isn't recognized as
2212     whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2213     class [:space:] *does* include VT, thereby creating a mess.
2214    
2215     5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2216     space and tab.
2217    
2218     6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2219     its new features into the main test script, reducing the number of scripts.
2220    
2221     7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2222     were backward compatible, and made the (?i) apply to the whole pattern, as if
2223     /i were given. Now it behaves more logically, and applies the option setting
2224     only to what follows. PCRE has been changed to follow suit. However, if it
2225     finds options settings right at the start of the pattern, it extracts them into
2226     the global options, as before. Thus, they show up in the info data.
2227    
2228     8. Added support for the \Q...\E escape sequence. Characters in between are
2229     treated as literals. This is slightly different from Perl in that $ and @ are
2230     also handled as literals inside the quotes. In Perl, they will cause variable
2231     interpolation. Note the following examples:
2232    
2233     Pattern PCRE matches Perl matches
2234    
2235     \Qabc$xyz\E abc$xyz abc followed by the contents of $xyz
2236     \Qabc\$xyz\E abc\$xyz abc\$xyz
2237     \Qabc\E\$\Qxyz\E abc$xyz abc$xyz
2238    
2239     For compatibility with Perl, \Q...\E sequences are recognized inside character
2240     classes as well as outside them.
2241    
2242     9. Re-organized 3 code statements in pcretest to avoid "overflow in
2243     floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2244     (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2245     signed/unsigned warnings.
2246    
2247     10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2248     option for pcretest, so I've replaced it by a simple function that does just
2249     that job.
2250    
2251     11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2252     "pcregrep -".
2253    
2254     12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2255     Java package. This provides some syntactic sugar for simple cases of what my
2256     documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2257     as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2258     item, you can use this simplified notation. Note that only makes sense with
2259     greedy quantifiers. Consequently, the use of the possessive quantifier forces
2260     greediness, whatever the setting of the PCRE_UNGREEDY option.
2261    
2262     13. A change of greediness default within a pattern was not taking effect at
2263     the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2264     subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2265     was abstracted outside.
2266    
2267     14. PCRE now supports the \G assertion. It is true when the current matching
2268     position is at the start point of the match. This differs from \A when the
2269     starting offset is non-zero. Used with the /g option of pcretest (or similar
2270     code), it works in the same way as it does for Perl's /g option. If all
2271     alternatives of a regex begin with \G, the expression is anchored to the start
2272     match position, and the "anchored" flag is set in the compiled expression.
2273    
2274     15. Some bugs concerning the handling of certain option changes within patterns
2275     have been fixed. These applied to options other than (?ims). For example,
2276     "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2277     been the other way round. Some of this was related to change 7 above.
2278    
2279     16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2280     features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2281     and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2282     POSIX classes only within a class (e.g. /[[:alpha:]]/).
2283    
2284     17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2285     mode. Unlike ".", it always matches newline, whatever the setting of
2286     PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2287     assertions. Perl allows it, but it doesn't (in general) work because it can't
2288     calculate the length of the lookbehind. At least, that's the case for Perl
2289     5.8.0 - I've been told they are going to document that it doesn't work in
2290     future.
2291    
2292     18. Added an error diagnosis for escapes that PCRE does not support: these are
2293     \L, \l, \N, \P, \p, \U, \u, and \X.
2294    
2295     19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2296     reading past the end of the pattern in cases such as /[abcd/.
2297    
2298     20. PCRE was getting more memory than necessary for patterns with classes that
2299     contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2300    
2301     21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2302     compiling PCRE for use with Virtual Pascal.
2303    
2304     22. Small fix to the Makefile to make it work properly if the build is done
2305     outside the source tree.
2306    
2307     23. Added a new extension: a condition to go with recursion. If a conditional
2308     subpattern starts with (?(R) the "true" branch is used if recursion has
2309     happened, whereas the "false" branch is used only at the top level.
2310    
2311     24. When there was a very long string of literal characters (over 255 bytes
2312     without UTF support, over 250 bytes with UTF support), the computation of how
2313     much memory was required could be incorrect, leading to segfaults or other
2314     strange effects.
2315    
2316     25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2317     start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2318     there was a subsequent back reference to those brackets. This meant that, for
2319     example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2320     possible to check for precisely this case. All we can do is abandon the
2321     optimization if .* occurs inside capturing brackets when there are any back
2322     references whatsoever. (See below for a better fix that came later.)
2323    
2324     26. The handling of the optimization for finding the first character of a
2325     non-anchored pattern, and for finding a character that is required later in the
2326     match were failing in some cases. This didn't break the matching; it just
2327     failed to optimize when it could. The way this is done has been re-implemented.
2328    
2329     27. Fixed typo in error message for invalid (?R item (it said "(?p").
2330    
2331     28. Added a new feature that provides some of the functionality that Perl
2332     provides with (?{...}). The facility is termed a "callout". The way it is done
2333     in PCRE is for the caller to provide an optional function, by setting
2334     pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2335     global variable. By default it is unset, which disables all calling out. To get
2336     the function called, the regex must include (?C) at appropriate points. This
2337     is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2338     This provides a means of identifying different callout points. When PCRE
2339     reaches such a point in the regex, if pcre_callout has been set, the external
2340     function is called. It is provided with data in a structure called
2341     pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2342     matching continues; if it returns a non-zero value, the match at the current
2343     point fails. However, backtracking will occur if possible. [This was changed
2344     later and other features added - see item 49 below.]
2345    
2346     29. pcretest is upgraded to test the callout functionality. It provides a
2347     callout function that displays information. By default, it shows the start of
2348     the match and the current position in the text. There are some new data escapes
2349     to vary what happens:
2350    
2351     \C+ in addition, show current contents of captured substrings
2352     \C- do not supply a callout function
2353     \C!n return 1 when callout number n is reached
2354     \C!n!m return 1 when callout number n is reached for the mth time
2355    
2356     30. If pcregrep was called with the -l option and just a single file name, it
2357     output "<stdin>" if a match was found, instead of the file name.
2358    
2359     31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2360     slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2361     pcre_exec(). This saves a malloc/free per call. The default value of
2362     POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2363     when configuring.
2364    
2365     32. The default maximum size of a compiled pattern is 64K. There have been a
2366     few cases of people hitting this limit. The code now uses macros to handle the
2367     storing of links as offsets within the compiled pattern. It defaults to 2-byte
2368     links, but this can be changed to 3 or 4 bytes by --with-link-size when
2369     configuring. Tests 2 and 5 work only with 2-byte links because they output
2370     debugging information about compiled patterns.
2371    
2372     33. Internal code re-arrangements:
2373    
2374     (a) Moved the debugging function for printing out a compiled regex into
2375     its own source file (printint.c) and used #include to pull it into
2376     pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2377     separate copies.
2378    
2379     (b) Defined the list of op-code names for debugging as a macro in
2380     internal.h so that it is next to the definition of the opcodes.
2381    
2382     (c) Defined a table of op-code lengths for simpler skipping along compiled
2383     code. This is again a macro in internal.h so that it is next to the
2384     definition of the opcodes.
2385    
2386     34. Added support for recursive calls to individual subpatterns, along the
2387     lines of Robin Houston's patch (but implemented somewhat differently).
2388    
2389     35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2390     allow it to read and process whole directories in Win32. This code was
2391     contributed by Lionel Fourquaux; it has not been tested by me.
2392    
2393     36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2394     used to name a group. Names consist of alphanumerics and underscores, and must
2395     be unique. Back references use the syntax (?P=name) and recursive calls use
2396     (?P>name) which is a PCRE extension to the Python extension. Groups still have
2397     numbers. The function pcre_fullinfo() can be used after compilation to extract
2398     a name/number map. There are three relevant calls:
2399    
2400     PCRE_INFO_NAMEENTRYSIZE yields the size of each entry in the map
2401     PCRE_INFO_NAMECOUNT yields the number of entries
2402     PCRE_INFO_NAMETABLE yields a pointer to the map.
2403    
2404     The map is a vector of fixed-size entries. The size of each entry depends on
2405     the length of the longest name used. The first two bytes of each entry are the
2406     group number, most significant byte first. There follows the corresponding
2407     name, zero terminated. The names are in alphabetical order.
2408    
2409     37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2410     case instead of 255. Making it the same both with and without UTF-8 support
2411     means that the same test output works with both.
2412    
2413     38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2414     calling malloc() with a zero argument.
2415    
2416     39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2417     optimization. I've improved things by keeping a bitmap of backreferences with
2418     numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2419     fact referenced, the optimization can be applied. It is unlikely that a
2420     relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2421     the match to follow \n) will appear inside brackets with a number greater than
2422     31, but if it does, any back reference > 31 suppresses the optimization.
2423    
2424     40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2425     of disabling numbered capturing parentheses. Any opening parenthesis that is
2426     not followed by ? behaves as if it were followed by ?: but named parentheses
2427     can still be used for capturing (and they will acquire numbers in the usual
2428     way).
2429    
2430     41. Redesigned the return codes from the match() function into yes/no/error so
2431     that errors can be passed back from deep inside the nested calls. A malloc
2432     failure while inside a recursive subpattern call now causes the
2433     PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2434    
2435     42. It is now possible to set a limit on the number of times the match()
2436     function is called in a call to pcre_exec(). This facility makes it possible to
2437     limit the amount of recursion and backtracking, though not in a directly
2438     obvious way, because the match() function is used in a number of different
2439     circumstances. The count starts from zero for each position in the subject
2440     string (for non-anchored patterns). The default limit is, for compatibility, a
2441     large number, namely 10 000 000. You can change this in two ways:
2442    
2443     (a) When configuring PCRE before making, you can use --with-match-limit=n
2444     to set a default value for the compiled library.
2445    
2446     (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2447     a different value is set. See 45 below.
2448    
2449     If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2450    
2451     43. Added a new function pcre_config(int, void *) to enable run-time extraction
2452     of things that can be changed at compile time. The first argument specifies
2453     what is wanted and the second points to where the information is to be placed.
2454     The current list of available information is:
2455    
2456     PCRE_CONFIG_UTF8
2457    
2458     The output is an integer that is set to one if UTF-8 support is available;
2459     otherwise it is set to zero.
2460    
2461     PCRE_CONFIG_NEWLINE
2462    
2463     The output is an integer that it set to the value of the code that is used for
2464     newline. It is either LF (10) or CR (13).
2465    
2466     PCRE_CONFIG_LINK_SIZE
2467    
2468     The output is an integer that contains the number of bytes used for internal
2469     linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2470    
2471     PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2472    
2473     The output is an integer that contains the threshold above which the POSIX
2474     interface uses malloc() for output vectors. See item 31 above.
2475    
2476     PCRE_CONFIG_MATCH_LIMIT
2477    
2478     The output is an unsigned integer that contains the default limit of the number
2479     of match() calls in a pcre_exec() execution. See 42 above.
2480    
2481     44. pcretest has been upgraded by the addition of the -C option. This causes it
2482     to extract all the available output from the new pcre_config() function, and to
2483     output it. The program then exits immediately.
2484    
2485     45. A need has arisen to pass over additional data with calls to pcre_exec() in
2486     order to support additional features. One way would have been to define
2487     pcre_exec2() (for example) with extra arguments, but this would not have been
2488     extensible, and would also have required all calls to the original function to
2489     be mapped to the new one. Instead, I have chosen to extend the mechanism that
2490     is used for passing in "extra" data from pcre_study().
2491    
2492     The pcre_extra structure is now exposed and defined in pcre.h. It currently
2493     contains the following fields:
2494    
2495     flags a bitmap indicating which of the following fields are set
2496     study_data opaque data from pcre_study()
2497     match_limit a way of specifying a limit on match() calls for a specific
2498     call to pcre_exec()
2499     callout_data data for callouts (see 49 below)
2500    
2501     The flag bits are also defined in pcre.h, and are
2502    
2503     PCRE_EXTRA_STUDY_DATA
2504     PCRE_EXTRA_MATCH_LIMIT
2505     PCRE_EXTRA_CALLOUT_DATA
2506    
2507     The pcre_study() function now returns one of these new pcre_extra blocks, with
2508     the actual study data pointed to by the study_data field, and the
2509     PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2510     before. That is, this change is entirely upwards-compatible and requires no
2511     change to existing code.
2512    
2513     If you want to pass in additional data to pcre_exec(), you can either place it
2514     in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2515     block.
2516    
2517     46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2518     data string contains the escape sequence \M, pcretest calls pcre_exec() several
2519     times with different match limits, until it finds the minimum value needed for
2520     pcre_exec() to complete. The value is then output. This can be instructive; for
2521     most simple matches the number is quite small, but for pathological cases it
2522     gets very large very quickly.
2523    
2524     47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2525     returns the size of the data block pointed to by the study_data field in a
2526     pcre_extra block, that is, the value that was passed as the argument to
2527     pcre_malloc() when PCRE was getting memory in which to place the information
2528     created by pcre_study(). The fourth argument should point to a size_t variable.
2529     pcretest has been extended so that this information is shown after a successful
2530     pcre_study() call when information about the compiled regex is being displayed.
2531    
2532     48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2533     because what follows is always an absolute path. (Later: it turns out that this
2534     is more than cosmetic for MinGW, because it doesn't like empty path
2535     components.)
2536    
2537     49. Some changes have been made to the callout feature (see 28 above):
2538    
2539     (i) A callout function now has three choices for what it returns:
2540    
2541     0 => success, carry on matching
2542     > 0 => failure at this point, but backtrack if possible
2543     < 0 => serious error, return this value from pcre_exec()
2544    
2545     Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2546     values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2547     "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2548     use by callout functions. It will never be used by PCRE itself.
2549    
2550     (ii) The pcre_extra structure (see 45 above) has a void * field called
2551     callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2552     pcre_callout_block structure has a field of the same name. The contents of
2553     the field passed in the pcre_extra structure are passed to the callout
2554     function in the corresponding field in the callout block. This makes it
2555     easier to use the same callout-containing regex from multiple threads. For
2556     testing, the pcretest program has a new data escape
2557    
2558     \C*n pass the number n (may be negative) as callout_data
2559    
2560     If the callout function in pcretest receives a non-zero value as
2561     callout_data, it returns that value.
2562    
2563     50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2564     there were some redundant $(CFLAGS) in commands that are now specified as
2565     $(LINK), which already includes $(CFLAGS).
2566    
2567     51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2568     has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2569     with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2570     one-byte characters throughout. Note that case-insensitive matching applies
2571     only to characters whose values are less than 256. PCRE doesn't support the
2572     notion of cases for higher-valued characters.
2573    
2574     (i) A character class whose characters are all within 0-255 is handled as
2575     a bit map, and the map is inverted for negative classes. Previously, a
2576     character > 255 always failed to match such a class; however it should
2577     match if the class was a negative one (e.g. [^ab]). This has been fixed.
2578    
2579     (ii) A negated character class with a single character < 255 is coded as
2580     "not this character" (OP_NOT). This wasn't working properly when the test
2581     character was multibyte, either singly or repeated.
2582    
2583     (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2584     mode, for example: \x{100}{2,3}.
2585    
2586     (iv) The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2587     singly or repeated) now correctly test multibyte characters. However,
2588     PCRE doesn't recognize any characters with values greater than 255 as
2589     digits, spaces, or word characters. Such characters always match \D, \S,
2590     and \W, and never match \d, \s, or \w.
2591    
2592     (v) Classes may now contain characters and character ranges with values
2593     greater than 255. For example: [ab\x{100}-\x{400}].
2594    
2595     (vi) pcregrep now has a --utf-8 option (synonym -u) which makes it call
2596     PCRE in UTF-8 mode.
2597    
2598     52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2599     PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2600     retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2601     value.)
2602    
2603     53. The single man page has become too large. I have therefore split it up into
2604     a number of separate man pages. These also give rise to individual HTML pages;
2605     these are now put in a separate directory, and there is an index.html page that
2606     lists them all. Some hyperlinking between the pages has been installed.
2607    
2608     54. Added convenience functions for handling named capturing parentheses.
2609    
2610     55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2611     aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2612     true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2613     are faulted.
2614    
2615     56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2616     calling configure. These values are used when compiling the dftables.c program
2617     which is run to generate the source of the default character tables. They
2618     default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2619     you will need to set these values.
2620    
2621     57. Updated the building process for Windows DLL, as provided by Fred Cox.
2622    
2623    
2624     Version 3.9 02-Jan-02
2625 nigel 61 ---------------------
2626    
2627     1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2628    
2629     2. If --disable-static was given, the building process failed when trying to
2630     build pcretest and pcregrep. (For some reason it was using libtool to compile
2631     them, which is not right, as they aren't part of the library.)
2632    
2633    
2634 nigel 59 Version 3.8 18-Dec-01
2635     ---------------------
2636    
2637     1. The experimental UTF-8 code was completely screwed up. It was packing the
2638     bytes in the wrong order. How dumb can you get?
2639    
2640    
2641 nigel 57 Version 3.7 29-Oct-01
2642     ---------------------
2643    
2644     1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2645     This caused pcretest, when used on the test data, to segfault. Unfortunately,
2646     this didn't happen under Solaris 8, where I normally test things.
2647    
2648 nigel 59 2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2649     doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2650     isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2651     this fix an hour or so after the initial 3.7 release.)
2652 nigel 57
2653 nigel 59
2654 nigel 55 Version 3.6 23-Oct-01
2655     ---------------------
2656    
2657     1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2658     offsets passed as NULL with zero offset count.
2659    
2660     2. The config.guess and config.sub files had not been updated when I moved to
2661     the latest autoconf.
2662    
2663    
2664 nigel 53 Version 3.5 15-Aug-01
2665     ---------------------
2666 nigel 5
2667 nigel 53 1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2668     had been forgotten.
2669    
2670     2. By using declared but undefined structures, we can avoid using "void"
2671     definitions in pcre.h while keeping the internal definitions of the structures
2672     private.
2673    
2674     3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2675     user point of view, this means that both static and shared libraries are built
2676     by default, but this can be individually controlled. More of the work of
2677     handling this static/shared cases is now inside libtool instead of PCRE's make
2678     file.
2679    
2680     4. The pcretest utility is now installed along with pcregrep because it is
2681     useful for users (to test regexs) and by doing this, it automatically gets
2682     relinked by libtool. The documentation has been turned into a man page, so
2683     there are now .1, .txt, and .html versions in /doc.
2684    
2685     5. Upgrades to pcregrep:
2686     (i) Added long-form option names like gnu grep.
2687     (ii) Added --help to list all options with an explanatory phrase.
2688     (iii) Added -r, --recursive to recurse into sub-directories.
2689     (iv) Added -f, --file to read patterns from a file.
2690    
2691     6. pcre_exec() was referring to its "code" argument before testing that
2692     argument for NULL (and giving an error if it was NULL).
2693    
2694     7. Upgraded Makefile.in to allow for compiling in a different directory from
2695     the source directory.
2696    
2697     8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2698     options bits, the pointer it was passed was to an int instead of to an unsigned
2699     long int. This mattered only on 64-bit systems.
2700    
2701     9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2702     generated) instead of pcre.in, which it its source. Also made the same change
2703     in several of the .c files.
2704    
2705     10. A new release of gcc defines printf() as a macro, which broke pcretest
2706     because it had an ifdef in the middle of a string argument for printf(). Fixed
2707     by using separate calls to printf().
2708    
2709     11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2710     script, to force use of CR or LF instead of \n in the source. On non-Unix
2711     systems, the value can be set in config.h.
2712    
2713     12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2714     absolute limit. Changed the text of the error message to make this clear, and
2715     likewise updated the man page.
2716    
2717     13. The limit of 99 on the number of capturing subpatterns has been removed.
2718     The new limit is 65535, which I hope will not be a "real" limit.
2719    
2720    
2721 nigel 51 Version 3.4 22-Aug-00
2722     ---------------------
2723    
2724     1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2725    
2726     2. Diagnose condition (?(0) as an error instead of crashing on matching.
2727    
2728    
2729 nigel 49 Version 3.3 01-Aug-00
2730     ---------------------
2731    
2732     1. If an octal character was given, but the value was greater than \377, it
2733     was not getting masked to the least significant bits, as documented. This could
2734     lead to crashes in some systems.
2735    
2736     2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2737     the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2738    
2739     3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2740     These just pass their arguments on to (pcre_free)(), but they are provided
2741     because some uses of PCRE bind it to non-C systems that can call its functions,
2742     but cannot call free() or pcre_free() directly.
2743    
2744     4. Add "make test" as a synonym for "make check". Corrected some comments in
2745     the Makefile.
2746    
2747     5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2748     Makefile.
2749    
2750     6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2751     command called pgrep for grepping around the active processes.
2752    
2753     7. Added the beginnings of support for UTF-8 character strings.
2754    
2755     8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2756     RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2757     the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2758     out for the ar command.)
2759    
2760    
2761 nigel 47 Version 3.2 12-May-00
2762     ---------------------
2763    
2764     This is purely a bug fixing release.
2765    
2766     1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2767     of ZA. This was just one example of several cases that could provoke this bug,
2768     which was introduced by change 9 of version 2.00. The code for breaking
2769     infinite loops after an iteration that matches an empty string was't working
2770     correctly.
2771    
2772     2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2773     when matched against abbab (for example). After matching an empty string, it
2774     wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2775     caused it to match further down the string than it should.
2776    
2777     3. The code contained an inclusion of sys/types.h. It isn't clear why this
2778     was there because it doesn't seem to be needed, and it causes trouble on some
2779     systems, as it is not a Standard C header. It has been removed.
2780    
2781     4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2782     were reported on the Macintosh. The changes were from
2783    
2784     while ((c = *(++ptr)) != 0 && c != '\n');
2785     to
2786     while ((c = *(++ptr)) != 0 && c != '\n') ;
2787    
2788     Totally extraordinary, but if that's what it takes...
2789    
2790     5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2791     available. Added HAVE_BCOPY and an autoconf test for it; if neither
2792     HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2793     assumes the way PCRE uses memmove() (always moving upwards).
2794    
2795     6. PCRE is being used in one environment where strchr() is not available. There
2796     was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2797     faster code anyway.
2798    
2799    
2800 nigel 45 Version 3.1 09-Feb-00
2801     ---------------------
2802    
2803     The only change in this release is the fixing of some bugs in Makefile.in for
2804     the "install" target:
2805    
2806     (1) It was failing to install pcreposix.h.
2807    
2808     (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2809    
2810    
2811 nigel 43 Version 3.0 01-Feb-00
2812     ---------------------
2813 nigel 41
2814     1. Add support for the /+ modifier to perltest (to output $` like it does in
2815     pcretest).
2816    
2817     2. Add support for the /g modifier to perltest.
2818    
2819     3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2820     matches null strings.
2821    
2822     4. Fix perltest so that it doesn't do unwanted things when fed an empty
2823     pattern. Perl treats empty patterns specially - it reuses the most recent
2824     pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2825     effect.
2826    
2827     5. The POSIX interface was broken in that it was just handing over the POSIX
2828     captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2829     required a bigger vector, with some working space on the end. This means that
2830     the POSIX wrapper now has to get and free some memory, and copy the results.
2831    
2832 nigel 43 6. Added some simple autoconf support, placing the test data and the
2833     documentation in separate directories, re-organizing some of the
2834     information files, and making it build pcre-config (a GNU standard). Also added
2835     libtool support for building PCRE as a shared library, which is now the
2836     default.
2837 nigel 41
2838 nigel 43 7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2839     09 are not valid octal constants. Single digits will be used for minor values
2840     less than 10.
2841    
2842     8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2843     existing programs that set these in the POSIX interface can use PCRE without
2844     modification.
2845    
2846     9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2847     return all that pcre_info() returns, plus additional data. The pcre_info()
2848     function is retained for compatibility, but is considered to be obsolete.
2849    
2850     10. Added experimental recursion feature (?R) to handle one common case that
2851     Perl 5.6 will be able to do with (?p{...}).
2852    
2853     11. Added support for POSIX character classes like [:alpha:], which Perl is
2854     adopting.
2855    
2856    
2857 nigel 39 Version 2.08 31-Aug-99
2858     ----------------------
2859    
2860     1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2861     trying to match at the startoffset position, but instead was moving forward to
2862     the next newline as if a previous match had failed.
2863    
2864     2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2865     and could get into a loop if a null string was matched other than at the start
2866     of the subject.
2867    
2868     3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2869     be distinguished at compile time, and for completeness also added PCRE_DATE.
2870    
2871     5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2872     in GnuWin32 environments.
2873    
2874    
2875 nigel 37 Version 2.07 29-Jul-99
2876     ----------------------
2877    
2878     1. The documentation is now supplied in plain text form and HTML as well as in
2879     the form of man page sources.
2880    
2881     2. C++ compilers don't like assigning (void *) values to other pointer types.
2882     In particular this affects malloc(). Although there is no problem in Standard
2883     C, I've put in casts to keep C++ compilers happy.
2884    
2885     3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2886     should be (const char *).
2887    
2888     4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2889     be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2890     However, I haven't made this a standard facility. The documentation doesn't
2891     mention it, and the Makefile doesn't support it.
2892    
2893     5. The Makefile now contains an "install" target, with editable destinations at
2894     the top of the file. The pcretest program is not installed.
2895    
2896     6. pgrep -V now gives the PCRE version number and date.
2897    
2898     7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2899     causing the entire string to be ignored, instead of just the last character.
2900    
2901     8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2902     non-matching string, it can take a very, very long time, even for strings of
2903     quite modest length, because of the nested recursion. PCRE now does better in
2904     some of these cases. It does this by remembering the last required literal
2905     character in the pattern, and pre-searching the subject to ensure it is present
2906     before running the real match. In other words, it applies a heuristic to detect
2907     some types of certain failure quickly, and in the above example, if presented
2908     with a string that has no trailing " it gives "no match" very quickly.
2909    
2910     9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2911     other alternatives are tried instead.
2912    
2913    
2914 nigel 35 Version 2.06 09-Jun-99
2915     ----------------------
2916    
2917     1. Change pcretest's output for amount of store used to show just the code
2918     space, because the remainder (the data block) varies in size between 32-bit and
2919     64-bit systems.
2920    
2921     2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2922     start matching at. This allows lookbehinds to work when searching for multiple
2923     occurrences in a string.
2924    
2925     3. Added additional options to pcretest for testing multiple occurrences:
2926    
2927     /+ outputs the rest of the string that follows a match
2928     /g loops for multiple occurrences, using the new startoffset argument
2929     /G loops for multiple occurrences by passing an incremented pointer
2930    
2931     4. PCRE wasn't doing the "first character" optimization for patterns starting
2932     with \b or \B, though it was doing it for other lookbehind assertions. That is,
2933     it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2934     the letter 'x'. On long subject strings, this gives a significant speed-up.
2935    
2936    
2937 nigel 33 Version 2.05 21-Apr-99
2938     ----------------------
2939    
2940     1. Changed the type of magic_number from int to long int so that it works
2941     properly on 16-bit systems.
2942    
2943     2. Fixed a bug which caused patterns starting with .* not to work correctly
2944     when the subject string contained newline characters. PCRE was assuming
2945     anchoring for such patterns in all cases, which is not correct because .* will
2946     not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2947     DOTALL is set at top level; otherwise it knows that patterns starting with .*
2948     must be retried after every newline in the subject.
2949    
2950    
2951 nigel 31 Version 2.04 18-Feb-99
2952     ----------------------
2953    
2954     1. For parenthesized subpatterns with repeats whose minimum was zero, the
2955     computation of the store needed to hold the pattern was incorrect (too large).
2956     If such patterns were nested a few deep, this could multiply and become a real
2957     problem.
2958    
2959     2. Added /M option to pcretest to show the memory requirement of a specific
2960     pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2961    
2962     3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2963     compiled in such a way that the backtracking after subsequent failure was
2964     pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2965     ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2966    
2967    
2968 nigel 29 Version 2.03 02-Feb-99
2969     ----------------------
2970    
2971     1. Fixed typo and small mistake in man page.
2972    
2973 nigel 31 2. Added 4th condition (GPL supersedes if conflict) and created separate
2974     LICENCE file containing the conditions.
2975 nigel 29
2976     3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2977     Perl, that is the internal \ allows the delimiter to be included in the
2978     pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2979     the final delimiter, add \ to the end of the pattern (to test the error).
2980    
2981     4. Added the convenience functions for extracting substrings after a successful
2982     match. Updated pcretest to make it able to test these functions.
2983    
2984    
2985 nigel 27 Version 2.02 14-Jan-99
2986     ----------------------
2987    
2988     1. Initialized the working variables associated with each extraction so that
2989     their saving and restoring doesn't refer to uninitialized store.
2990    
2991     2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2992     compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2993     fix the problem.
2994    
2995     3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2996     calls, and wasn't printing the correct value for compiling calls. Increased the
2997     default value of LOOPREPEAT, and the number of significant figures in the
2998     times.
2999    
3000     4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3001    
3002     5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3003     a building problem on Windows NT with a FAT file system.
3004    
3005    
3006 nigel 25 Version 2.01 21-Oct-98
3007     ----------------------
3008    
3009     1. Changed the API for pcre_compile() to allow for the provision of a pointer
3010     to character tables built by pcre_maketables() in the current locale. If NULL
3011     is passed, the default tables are used.
3012    
3013    
3014 nigel 23 Version 2.00 24-Sep-98
3015 nigel 21 ----------------------
3016    
3017 nigel 23 1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3018     it any more.
3019    
3020     2. Allow quantification of (?>) groups, and make it work correctly.
3021    
3022     3. The first character computation wasn't working for (?>) groups.
3023    
3024     4. Correct the implementation of \Z (it is permitted to match on the \n at the
3025     end of the subject) and add 5.005's \z, which really does match only at the
3026     very end of the subject.
3027    
3028     5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3029    
3030     6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3031     DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3032     localized options. All options to pcre_study() were also removed.
3033    
3034     7. Add other new features from 5.005:
3035    
3036     $(?<= positive lookbehind
3037     $(?<! negative lookbehind
3038     (?imsx-imsx) added the unsetting capability
3039     such a setting is global if at outer level; local otherwise
3040     (?imsx-imsx:) non-capturing groups with option setting
3041     (?(cond)re|re) conditional pattern matching
3042    
3043     A backreference to itself in a repeated group matches the previous
3044     captured string.
3045    
3046     8. General tidying up of studying (both automatic and via "study")
3047     consequential on the addition of new assertions.
3048    
3049     9. As in 5.005, unlimited repeated groups that could match an empty substring
3050     are no longer faulted at compile time. Instead, the loop is forcibly broken at
3051     runtime if any iteration does actually match an empty substring.
3052    
3053     10. Include the RunTest script in the distribution.
3054    
3055     11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3056     discrepancies, some of which were old and were also with respect to 5.004. They
3057     have now been fixed.
3058    
3059    
3060     Version 1.09 28-Apr-98
3061     ----------------------
3062    
3063 nigel 21 1. A negated single character class followed by a quantifier with a minimum
3064     value of one (e.g. [^x]{1,6} ) was not compiled correctly. This could lead to
3065     program crashes, or just wrong answers. This did not apply to negated classes
3066     containing more than one character, or to minima other than one.
3067    
3068    
3069 nigel 19 Version 1.08 27-Mar-98
3070     ----------------------
3071    
3072     1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3073    
3074     2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3075     latter must appear before anything that relies on it in the pattern.
3076    
3077    
3078 nigel 17 Version 1.07 16-Feb-98
3079     ----------------------
3080    
3081     1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3082     repeat of a potentially empty string).
3083    
3084    
3085 nigel 15 Version 1.06 23-Jan-98
3086     ----------------------
3087    
3088     1. Added Markus Oberhumer's little patches for C++.
3089    
3090     2. Literal strings longer than 255 characters were broken.
3091    
3092    
3093 nigel 13 Version 1.05 23-Dec-97
3094     ----------------------
3095    
3096     1. Negated character classes containing more than one character were failing if
3097     PCRE_CASELESS was set at run time.
3098    
3099    
3100 nigel 11 Version 1.04 19-Dec-97
3101     ----------------------
3102    
3103     1. Corrected the man page, where some "const" qualifiers had been omitted.
3104    
3105     2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3106     input syntax.
3107    
3108     3. Fixed memory leak which occurred when a regex with back references was
3109     matched with an offsets vector that wasn't big enough. The temporary memory
3110     that is used in this case wasn't being freed if the match failed.
3111    
3112     4. Tidied pcretest to ensure it frees memory that it gets.
3113    
3114     5. Temporary memory was being obtained in the case where the passed offsets
3115     vector was exactly big enough.
3116    
3117     6. Corrected definition of offsetof() from change 5 below.
3118    
3119     7. I had screwed up change 6 below and broken the rules for the use of
3120     setjmp(). Now fixed.
3121    
3122    
3123 nigel 9 Version 1.03 18-Dec-97
3124     ----------------------
3125    
3126     1. A erroneous regex with a missing opening parenthesis was correctly
3127     diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3128     on some systems.
3129    
3130     2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3131     it was reported that one broken compiler failed on the former because "code" is
3132     also an independent variable.
3133    
3134     3. The erroneous regex a[]b caused an array overrun reference.
3135    
3136     4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3137     fail on data ending with that character. (It was going on too far, and checking
3138     the next character, typically a binary zero.) This was specific to the
3139     optimized code for single-character negative classes.
3140    
3141     5. Added a contributed patch from the TIN world which does the following:
3142    
3143     + Add an undef for memmove, in case the the system defines a macro for it.
3144    
3145     + Add a definition of offsetof(), in case there isn't one. (I don't know
3146     the reason behind this - offsetof() is part of the ANSI standard - but
3147     it does no harm).
3148    
3149     + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3150     most of the places where whitespace preceded '#'. I have given up and
3151     allowed the remaining 2 cases to be at the margin.
3152    
3153     + Rename some variables in pcre to eliminate shadowing. This seems very
3154     pedantic, but does no harm, of course.
3155    
3156     6. Moved the call to setjmp() into its own function, to get rid of warnings
3157     from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3158    
3159     7. Constructs such as \d{8,} were compiling into the equivalent of
3160 nigel 11 \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3161 nigel 9 outcome, but in this particular case used more store than had been allocated,
3162     which caused the bug to be discovered because it threw up an internal error.
3163    
3164     8. The debugging code in both pcre and pcretest for outputting the compiled
3165     form of a regex was going wrong in the case of back references followed by
3166     curly-bracketed repeats.
3167    
3168    
3169 nigel 7 Version 1.02 12-Dec-97
3170     ----------------------
3171    
3172     1. Typos in pcre.3 and comments in the source fixed.
3173    
3174     2. Applied a contributed patch to get rid of places where it used to remove
3175     'const' from variables, and fixed some signed/unsigned and uninitialized
3176     variable warnings.
3177    
3178     3. Added the "runtest" target to Makefile.
3179    
3180     4. Set default compiler flag to -O2 rather than just -O.
3181    
3182    
3183 nigel 5 Version 1.01 19-Nov-97
3184     ----------------------
3185    
3186     1. PCRE was failing to diagnose unlimited repeat of empty string for patterns
3187     like /([ab]*)*/, that is, for classes with more than one character in them.
3188    
3189     2. Likewise, it wasn't diagnosing patterns with "once-only" subpatterns, such
3190     as /((?>a*))*/ (a PCRE_EXTRA facility).
3191    
3192    
3193     Version 1.00 18-Nov-97
3194     ----------------------
3195    
3196     1. Added compile-time macros to support systems such as SunOS4 which don't have
3197     memmove() or strerror() but have other things that can be used instead.
3198    
3199     2. Arranged that "make clean" removes the executables.
3200    
3201    
3202 nigel 3 Version 0.99 27-Oct-97
3203     ----------------------
3204    
3205     1. Fixed bug in code for optimizing classes with only one character. It was
3206     initializing a 32-byte map regardless, which could cause it to run off the end
3207     of the memory it had got.
3208    
3209     2. Added, conditional on PCRE_EXTRA, the proposed (?>REGEX) construction.
3210    
3211    
3212     Version 0.98 22-Oct-97
3213     ----------------------
3214    
3215     1. Fixed bug in code for handling temporary memory usage when there are more
3216     back references than supplied space in the ovector. This could cause segfaults.
3217    
3218    
3219     Version 0.97 21-Oct-97
3220     ----------------------
3221    
3222     1. Added the \X "cut" facility, conditional on PCRE_EXTRA.
3223    
3224     2. Optimized negated single characters not to use a bit map.
3225    
3226     3. Brought error texts together as macro definitions; clarified some of them;
3227     fixed one that was wrong - it said "range out of order" when it meant "invalid
3228     escape sequence".
3229    
3230     4. Changed some char * arguments to const char *.
3231    
3232     5. Added PCRE_NOTBOL and PCRE_NOTEOL (from POSIX).
3233    
3234     6. Added the POSIX-style API wrapper in pcreposix.a and testing facilities in
3235     pcretest.
3236    
3237    
3238     Version 0.96 16-Oct-97
3239     ----------------------
3240    
3241     1. Added a simple "pgrep" utility to the distribution.
3242    
3243     2. Fixed an incompatibility with Perl: "{" is now treated as a normal character
3244     unless it appears in one of the precise forms "{ddd}", "{ddd,}", or "{ddd,ddd}"
3245     where "ddd" means "one or more decimal digits".
3246    
3247     3. Fixed serious bug. If a pattern had a back reference, but the call to
3248     pcre_exec() didn't supply a large enough ovector to record the related
3249     identifying subpattern, the match always failed. PCRE now remembers the number
3250     of the largest back reference, and gets some temporary memory in which to save
3251     the offsets during matching if necessary, in order to ensure that
3252     backreferences always work.
3253    
3254     4. Increased the compatibility with Perl in a number of ways:
3255    
3256     (a) . no longer matches \n by default; an option PCRE_DOTALL is provided
3257     to request this handling. The option can be set at compile or exec time.
3258    
3259     (b) $ matches before a terminating newline by default; an option
3260     PCRE_DOLLAR_ENDONLY is provided to override this (but not in multiline
3261     mode). The option can be set at compile or exec time.
3262    
3263     (c) The handling of \ followed by a digit other than 0 is now supposed to be
3264     the same as Perl's. If the decimal number it represents is less than 10
3265     or there aren't that many previous left capturing parentheses, an octal
3266     escape is read. Inside a character class, it's always an octal escape,
3267     even if it is a single digit.
3268    
3269     (d) An escaped but undefined alphabetic character is taken as a literal,
3270     unless PCRE_EXTRA is set. Currently this just reserves the remaining
3271     escapes.
3272    
3273     (e) {0} is now permitted. (The previous item is removed from the compiled
3274     pattern).
3275    
3276     5. Changed all the names of code files so that the basic parts are no longer
3277     than 10 characters, and abolished the teeny "globals.c" file.
3278    
3279     6. Changed the handling of character classes; they are now done with a 32-byte
3280     bit map always.
3281    
3282     7. Added the -d and /D options to pcretest to make it possible to look at the
3283     internals of compilation without having to recompile pcre.
3284    
3285    
3286     Version 0.95 23-Sep-97
3287     ----------------------
3288    
3289     1. Fixed bug in pre-pass concerning escaped "normal" characters such as \x5c or
3290     \x20 at the start of a run of normal characters. These were being treated as
3291     real characters, instead of the source characters being re-checked.
3292    
3293    
3294     Version 0.94 18-Sep-97
3295     ----------------------
3296    
3297     1. The functions are now thread-safe, with the caveat that the global variables
3298     containing pointers to malloc() and free() or alternative functions are the
3299     same for all threads.
3300    
3301     2. Get pcre_study() to generate a bitmap of initial characters for non-
3302     anchored patterns when this is possible, and use it if passed to pcre_exec().
3303    
3304    
3305     Version 0.93 15-Sep-97
3306     ----------------------
3307    
3308     1. /(b)|(:+)/ was computing an incorrect first character.
3309    
3310     2. Add pcre_study() to the API and the passing of pcre_extra to pcre_exec(),
3311     but not actually doing anything yet.
3312    
3313     3. Treat "-" characters in classes that cannot be part of ranges as literals,
3314     as Perl does (e.g. [-az] or [az-]).
3315    
3316     4. Set the anchored flag if a branch starts with .* or .*? because that tests
3317     all possible positions.
3318    
3319     5. Split up into different modules to avoid including unneeded functions in a
3320     compiled binary. However, compile and exec are still in one module. The "study"
3321     function is split off.
3322    
3323     6. The character tables are now in a separate module whose source is generated
3324     by an auxiliary program - but can then be edited by hand if required. There are
3325     now no calls to isalnum(), isspace(), isdigit(), isxdigit(), tolower() or
3326     toupper() in the code.
3327    
3328     7. Turn the malloc/free funtions variables into pcre_malloc and pcre_free and
3329     make them global. Abolish the function for setting them, as the caller can now
3330     set them directly.
3331    
3332    
3333     Version 0.92 11-Sep-97
3334     ----------------------
3335    
3336     1. A repeat with a fixed maximum and a minimum of 1 for an ordinary character
3337     (e.g. /a{1,3}/) was broken (I mis-optimized it).
3338    
3339     2. Caseless matching was not working in character classes if the characters in
3340     the pattern were in upper case.
3341    
3342     3. Make ranges like [W-c] work in the same way as Perl for caseless matching.
3343    
3344     4. Make PCRE_ANCHORED public and accept as a compile option.
3345    
3346     5. Add an options word to pcre_exec() and accept PCRE_ANCHORED and
3347     PCRE_CASELESS at run time. Add escapes \A and \I to pcretest to cause it to
3348     pass them.
3349    
3350     6. Give an error if bad option bits passed at compile or run time.
3351    
3352     7. Add PCRE_MULTILINE at compile and exec time, and (?m) as well. Add \M to
3353     pcretest to cause it to pass that flag.
3354    
3355     8. Add pcre_info(), to get the number of identifying subpatterns, the stored
3356     options, and the first character, if set.
3357    
3358     9. Recognize C+ or C{n,m} where n >= 1 as providing a fixed starting character.
3359    
3360    
3361     Version 0.91 10-Sep-97
3362     ----------------------
3363    
3364     1. PCRE was failing to diagnose unlimited repeats of subpatterns that could
3365     match the empty string as in /(a*)*/. It was looping and ultimately crashing.
3366    
3367     2. PCRE was looping on encountering an indefinitely repeated back reference to
3368     a subpattern that had matched an empty string, e.g. /(a|)\1*/. It now does what
3369     Perl does - treats the match as successful.
3370    
3371     ****

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